WO2001064109A1

WO2001064109A1 - Ultrasonic medical device and associated method

Info

Publication number: WO2001064109A1
Application number: PCT/US2001/006199
Authority: WO
Inventors: Peter J. Wilk; Timothy J. Nohara; Peter T. Weber
Original assignee: Wilk Ultrasound Of Canada, Inc.
Priority date: 2000-02-28
Filing date: 2001-02-26
Publication date: 2001-09-07
Also published as: EP1259166A1; US20050020918A1; US8235907B2; US7597665B2; AU2001238701A1; US20080228077A1; US7497828B1

Abstract

A medical system includes a carrier (100) an multiplicity of electromechanical transducers (126) mounted to the carrier (100), the transducers (126) being disposable in effective pressure-wave-transmitting contact with a patient. Energization componentry is operatively connected to a first plurality of the transducers for supplying the same with electrical signals of at least one pre-established ultrasonic frequency to produce first pressure waves in the patient. A control unit (140) is operatively connected to the energization componentry and includes an electronic analyzer operatively connected to a second plurality of the transducers for performing electronic 3D volumetric data acquisition and imaging of internal tissue structures of the patient by analyzing signals generated by the second plurality of the transducers in response to second pressure waves produced at the internal tissue structures in response to the first pressure waves. The control unit (140) includes a phased array signal processing circuitry for effectuating an electronic scanning of the internal tissue structures.

Description

ULTRASONIC MEDICAL DEVICE AND ASSOCIATED METHOD

BACKGROUND OF THE INVENTION

This invention relates to a device or system for use in medical diagnoses and treatment.

The device or system is especially useful for medical imaging purposes to enable a visual

inspection of internal tissue structures.

In recent years, the escalation of medical costs has captured substantial media and

regulatory attention. One reason for the escalating costs is the ever increasing use of expensive

machines and testing techniques. Computed assisted tomography (CAT scanning), magnetic

resonance imaging (MRI) and some radiological techniques have been in the forefront of

contributing to mounting medical costs. In addition to being expensive, these devices are heavy

and bulky, making them ill suited to transport.

In this age of rapidly escalating medical costs, minimally invasive operations have

become the method of choice for diagnosis and treatment. In many cases, endoscopic,

laparoscopic and radiographic techniques have superseded older diagnostic and therapeutic

surgical techniques.

Ultrasonic imaging tools are not uncommon in medical offices. These existing devices

invariably include a probe provided at a distal or free end with an ultrasonic transducer. The

operator moves the probe over a skin surface of a patient while viewing images generated on a

video monitor. Upon detecting an image containing information of interest, the operator presses

a button to record the image.

The images produced during a conventional ultrasonic scanning procedure are not easily decipherable. Even physicians intimately familiar with internal tissue structures of human beings

find it difficult to read conventional ultrasonically generated images without substantial training.

Conventional ultrasound images are two-dimensional (2D) and represent a cross-sectional

cut or plane through internal tissues. The data needed for these 2D images are acquired

electronically using the probe. The probe scans electronically in a single lateral or length

dimension to scan a beam and hence is referred to as a one-dimensional (ID) transducer array;

and the second dimension in a 2D image is the range or depth dimension (i.e into the body).

Interest in three-dimensional (3D) ultrasound imaging is increasing rapidly, notwithstanding the

fact that presently, it is not possible to obtain electronic 3D volumetric data acquisition.

Electronic 3D volumetric data acquisition requires a probe that can electronically scan in a width

dimension as well as a length dimension (i.e. the probe must incorporate a 2D transducer array).

Such probes are not currently available, and are not expected to be in the near future due to

multiplicative complexities known to those skilled in the art in implementing a 2D transducer

array, However, 1.5D transducer arrays are available. These arrays scan only in one dimension

(i.e. the length dimension) as the ID transducer arrays; however, they include a few additional

rows of transducer elements in the width dimension giving the appearance of a rectangular 2D

array. The purpose of the few additional rows (where each row is effectively a ID array

consisting typically of approximately 100 transducer elements) of elements is to provide better

focus in the width dimension as a function of depth.

OBJECTS OF THE INVENTION

An object of the present invention is to provide an imaging device or system which is relatively inexpensive and easy to transport.

It is another object of the present invention to provide an alternative to conventional

medical imaging systems.

A further object of the present invention is to provide a medical imaging system which

exhibits reduced costs over conventional imaging systems such as CAT scanners and MRI

machines.

A particular object of the present invention is to provide a medical imaging system which

can be used during the performance of so-called minimally invasive medical operations.

It is an additional object of the present invention to provide a medical imaging system

which is portable.

Another object of the present invention is to provide a medical operating method which

provides real time imaging in a cost effective manner.

A particular object of the present invention is to provide electronic, three-dimensional

(3D) volumetric data acquisition using an ultrasonic imaging device or system. Another object

of the present invention is to provide both conventional two-dimensional (2D) image and 3D

image processing.

These and other objects of the present invention will be apparent from the drawings and

descriptions herein.

SUMMARY OF THE INVENTION

A medical system comprises, in accordance with the present invention, a carrier and a

multiplicity of electromechanical transducers mounted to the carrier, the transducers being disposable in effective pressure-wave-transmitting contact with a patient. Energization

componentry is operatively connected to a first plurality of the transducers for supplying the

same with electrical signals of at least one pre-established ultrasonic frequency to produce first

pressure waves in the patient. A control unit is operatively connected to the energization

componentry and includes an electronic analyzer operatively connected to a second plurality of

the transducers for performing electronic 3D volumetric data acquisition and imaging (which

includes determining three-dimensional shapes) of internal tissue structures of the patient by analyzing signals generated by the second plurality of the transducers in response to second

pressure waves produced at the internal tissue structures in response to the first pressure waves.

The control unit includes phased-array signal processing circuitry for effectuating an electronic scanning of the internal tissue structures which facilitates one-dimensional (vector), 2D (planar)

and 3D (volume) data acquisition. Vector data acquisition is a special case of planar data

acquisition, which is a special case of volume data acquisition.

In a specific embodiment of the invention, the carrier is rigid. More specifically, the

carrier comprises a plurality of rigid modular substrates rigidly connected to one another, each of the substrates holding a plurality of the transducers. The modular substrates are off-the-shelf components such as the 1.5D (or 1.75D) transducer arrays found in conventional, premium probes, with on the order of 100 piezoelectric transducers (or elements) disposed in a tightly packed line along a length dimension of the substrate. Inter-element spacing is typically one wavelength or less to support full scanning along the length dimension. A width dimension of a

modular substrate carries substantially fewer (e.g. less than 10) piezoelectric transducers. Both the inter-element spacing and element size along the width dimension is typically a few or

several wavelengths. The electronic scanning of internal tissue structures of a patient along the

length dimension is performed conventionally by the control unit. The control unit also provides

electronic scanning of internal tissue structures of a patient in the width dimensions of the

modular substrates, where the density of the transducers is low, using a procedure unique to the

present invention which is described in detail below. The rigid carrier may be planar (flat) or

curved in its shape so as to be conformal to a patient's body.

The carrier may be provided with a fluid-filled flexible bag disposable in contact with the

patient for facilitating transmission of the first pressure waves into the patient from the first

plurality of transducers and reception of the second pressure waves by the second plurality of

transducers.

In accordance with a feature of the present invention, the phased-array signal processing

circuitry includes switching circuitry or other means operatively connected to the energization

componentry for independently varying the time-delays or phases of the electrical signals across

the first plurality of the transducers to effectuate an electronic scanning of the internal tissue

structures of the patient by the first pressure waves. Alternatively or additionally, the phased-

array signal processing circuitry includes switching circuitry or other means for varying sampling

times or phases of the second pressure waves received at the second plurality of the transducers

and further includes combining circuitry for combining the sampled signals to effectuate an

electronic scanning of the second pressure waves by the second plurality of transducers. The

effect of the aforementioned phased-array signal processing circuitry is to dynamically focus the pressure waves into spatially directed beams of energy and to provide electronic sequential beam

scanning and/or beam steering in order to interrogate the internal tissue structures of the patient.

The principles of sequential beam scanning and beam steering are known to those skilled in the

art.

The transmitting transducers may be used also for receiving. However, there may be

transducers which are dedicated to one task or the other.

In accordance with another feature of the present invention, the control unit includes

circuitry operatively connected to the energization componentry for varying the frequency to

facilitate collection of three-dimensional structural data pertaining to tissue structures at different

depths in the patient.

A system in accordance with the present invention is generally useful in the generation of

2D and 3D images of internal tissue structures of a living being such as a human medical patient.

To that end, at least one display is operatively connected to the electronic analyzer for providing

an image of the internal tissue structures of the patient.

A related medical method comprises, in accordance with the present invention, (a)

placing a carrier holding a multiplicity of electromechanical transducers and a patient adjacent to

one another so that the transducers are disposed in effective pressure-wave-transmitting contact

with the patient, (b) supplying a first plurality of the transducers with electrical signals of at least

one pre-established ultrasonic frequency to produce first pressure waves in the patient, (c)

receiving, via a second plurality of the transducers, second pressure waves produced at internal

tissue structures of the patient in response to the first pressure waves, and (d) performing electronic 3D volumetric data acquisition and imaging (which includes determining three-

dimensional shapes) of the internal tissue structures by analyzing signals generated by the second

plurality of the transducers in response to the second pressure waves. At least one of the

supplying and receiving steps is executed to effectuate electronic scanning of the internal tissue

structures.

The electronic scanning may be accomplished by varying the time delays or phases of the

electrical signals across the first plurality of the transducers to effectuate a phased-array

electronic scanning of internal tissues of the patient by the first pressure waves. Alternatively or

additionally, the electronic scanning is accomplished by varying sampling times or phases of the

second plurality of the transducers to effectuate an electronic scanning of the second pressure

waves by the second plurality of transducers. In the former case, the varying of the time delay or

phase of the electrical signals may include operating switching circuitry operatively connected to

the first plurality of the transducers. In the latter case, the varying of the time delay or phase of

the electrical signals may include operating switching circuitry operatively connected to the

second plurality of the transducers.

The method preferably further comprises disposing a flexible fluid-filled bag between the

patient and the carrier and transmitting the first pressure waves and receiving the second pressure

waves through the fluid filled flexible bag. The flexible bag ensures positive pressure wave

transmission and reception and effectively conforms the ultrasonic system to the irregular body

profile of the patient.

A medical system comprises, in accordance with another conceptualization of the present invention, a carrier, a multiplicity of electromechanical transducers mounted to the carrier, and

energization componentry operatively connected to a first plurality of the transducers for

supplying the same with electrical signals of at least one pre-established ultrasonic frequency to

produce first pressure waves in the patient. The system further comprises a control unit

operatively connected to the energization componentry for operating the same to produce the first

pressure waves in the patient. The control unit includes an electronic analyzer operatively

connected to a second plurality of the transducers for performing electronic 3D volumetric data

acquisition and imaging of internal tissues of the patient by analyzing signals generated by the

second plurality of the transducers in response to second pressure waves produced at internal tissues of the patient in response to the first pressure waves. The control unit is operatively

connected to the second plurality of the transducers to gather and organize data from the second plurality of the transducers so that the second plurality of transducers define a plurality of data gathering apertures which are unique to this invention. A subset of the second plurality of the

transducers is used in each data gathering aperture. Data can be gathered from the defined data gathering apertures sequentially in time or simultaneously. Electronic scanning is performed by

each data gathering aperture to interrogate and acquire structural data from a desired spatial

region. The control unit includes coherent aperture combining (CAC) circuitry for coherently

combining structural data from the respective data gathering apertures, which is a unique feature of this invention. The resultant effective increase in total aperture size improves the resolution capability of the imaging system. The control unit may also include circuitry for noncoherently combining structural data, which allows extended images to be created without increasing the imaging resolution.

In a particular embodiment of the present invention, the transducers are disposed on or

form rigid substrates in turn movably connected to one another, e.g., via a flexible web carrier.

In this embodiment, the individual substrates form separate data gathering apertures, and the

coherent aperture combining circuitry includes or is connected to position determination

elements for determining relative positions and orientations of the substrates relative to one

another. The position determination elements may include a multiplicity of point scatterers, a

subset of which are visible to (i.e., can be scanned by) each of the substrates in question, the

position determination element further including programmed componentry operatively

connected to the energization componentry for periodically scanning the point scatterers with

first ultrasonic pressure waves and calculating instantaneous positions of the point scatterers as

seen by each substrate in question using the reflected second ultrasonic pressure waves.

Alternatively, the first ultrasonic pressure wave signals received directly by a plurality of distinct

transducers (different from those used to generate the first pressure waves) can be used in place

of point scatterers (and their associated reflected second pressure waves) to calculate the

instantaneous positions of the distinct transducers as seen by each of the substrates in question.

In either case, the position determination elements include circuitry for executing computations

according to a self-cohering algorithm that computes each substrate's relative position and

orientation using the instantaneous position measurements, and adjusts the signals from the

coherently combined apertures so they can be added together constructively.

For medical diagnostic and treatment purposes, at least one display is operatively connected to the electronic analyzer for providing an image of the internal tissue structures of the

patient.

An associated medical method comprises, in accordance with the present invention, (i)

providing a carrier holding a multiplicity of electromechanical transducers forming a plurality of

data gathering apertures, (ii) placing the carrier and a patient adjacent to one another so that the

transducers are disposed in effective pressure-wave-transmitting contact with the patient, (iii)

supplying a first plurality of the transducers with electrical signals of at least one pre-established

ultrasonic frequency to produce first pressure waves in the patient, (iv) receiving, via a second

plurality of the transducers, second pressure waves produced at internal tissue structures of the

patient in response to the first pressure waves, and (v) performing electronic 3D volumetric data

acquisition and imaging (which includes determining three-dimensional shapes) of the internal

tissue structures by analyzing signals generated by the second plurality of the transducers in

response to the second pressure waves.

The carrier may take any of several forms. In one form, the carrier is a flexible web, with

the transducers being individual scalar elements distributed in an array throughout at least a

substantial portion of the web. In this case, the various data gathering apertures are defined by

signal processing: either the first plurality of transducers is energized in groups, or the second

plurality of transducers is sampled (i.e. received) in groups, or both. This electronic grouping of

transducers may be varied from instant to instant, depending on the imaging requirements. In

another form of the carrier, a plurality of rigid carrier substrates are movably attached to one another (e.g., via a flexible web or sheet), each substrate bearing a respective set of scalar

transducer elements. The substrates with their respective transducers easily or conveniently (but

not necessarily) define respective data gathering apertures. In either of these forms of the carrier,

one or both of the steps of transmitting and receiving may include coherently combining

structural data from the respective apertures using CAC. In both cases, a self-cohering algorithm

is used to compute relative positions and orientations of the transducer scalar elements or rigid

carrier substrates, as the case may be, using instantaneous position measurements and to adjust

signals from each coherently combined aperture to enable constructive addition of those signals

from the coherently combined apertures.

The carrier may alternatively take the form of a singular rigid structure constructed using

scalar transducer elements arranged in the likeness of an array, or a rigid form constructed from a

plurality of modular rigid substrates (where each substrate consists of one or more ID or 1.5D

arrays, and where each array contains a plurality of scalar transducer elements) rigidly connected

to one another and arranged in the likeness of an array. In these cases, the positions and

orientations of all transducers relative to each other are known; no calibration or position

determination circuitry is necessary. Signal transmission apertures and data gathering apertures

are formed and used to electronically scan desired regions and electronically acquire 3D

volumetric data. Each signal transmission aperture is formed by grouping a first plurality of

transducer elements and each data gathering aperture is formed by grouping a second plurality of

transducer elements. Coherent aperture combining can be used to combine the structural data

from multiple data gathering apertures without a self-cohering algorithm. Noncoherent combination of structural data from respective apertures may also be performed.

Where CAC is employed to combine structural data from multiple data gathering

apertures and the relative positions and orientations of those apertures are unknown, the coherent

combining of structural data preferentially includes determining relative positions and

orientations of the data gathering apertures relative to one another. Where point scatterers are

visible to transducers on the data gathering apertures , the determining of relative positions and

orientations of these apertures includes periodically scanning, using a plurality of transducer

elements on the respective apertures , of the point scatterers with first ultrasonic pressure waves

and calculating the instantaneous positions of the point scatterers as seen by the respective

plurality of transducer elements using reflected pressure waves. Where a distinct plurality of

transducers are used in place of point scatterers, direct measurements of pressure waves received

by those distinct transducers are used to calculate the instantaneous positions of those distinct

transducers relative to respective plurality of transducers transmitting the first pressure waves. In

either case, the determining of relative positions and orientations of the data gathering apertures

entails executing computations according to a self-cohering algorithm.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram of a medical diagnostic system, which may utilize or incorporate

an ultrasonographic imaging device in accordance with the present invention.

Fig. 2 is a flow-chart diagram illustrating steps in a mode of operation of the diagnostic

system of Fig. 1.

Fig. 3 is a flow-chart diagram illustrating steps in another mode of operation of the diagnostic system of Fig. 1.

Fig. 4 a block diagram of a further medical diagnostic system.

Fig. 5 is a diagram showing the composition of a data string or module used in the system

of Fig. 4.

Fig. 6 is a block diagram of a computerized slide scanning system.

Fig. 7 is a block diagram of a device for measuring a diagnostic parameter and

transmitting the measurement over the telephone lines.

Fig. 8 is a diagram of an ultrasonography device

Fig. 9 is a diagram showing a modification of the device of Fig. 8.

Fig. 10 is a block diagram of an ultrasonographic imaging apparatus similar to the device

of Figs. 8 and 9, for use in diagnostic and therapeutic procedures.

Fig. 11 is a block diagram showing a modification of the apparatus illustrated in Fig. 10.

Fig. 12 is partially a schematic perspective view and partially a block diagram showing

use of an ultrasonographic imaging device in a minimally invasive diagnostic or therapeutic

procedure.

Fig. 13 is a partial schematic perspective view including a block diagram showing use of

an ultrasonographic imaging device in another minimally invasive diagnostic or therapeutic

procedure.

Fig. 14 is a schematic perspective view of yet another ultrasonographic imaging device

which includes a sensor vest in a closed, use configuration.

Fig. 15 is a schematic perspective view of the sensor vest of Fig. 14, showing the vest in an open configuration.

Fig. 16 is partially a schematic perspective view and partially a block diagram of an

ultrasonic diagnostic imaging device.

Fig. 17 is partially a schematic perspective view and partially a block diagram of the

ultrasonic diagnostic imaging device of Fig. 16, showing the device in use with a patient.

Fig. 18 is partially a schematic perspective view and partially a block diagram of another

ultrasonic diagnostic imaging device, showing the device in use with a patient.

Fig. 19 is partially a schematic perspective view and partially a block diagram of the

ultrasonic diagnostic imaging device of Figs. 17 and 18, showing a modification of the device of

those figures.

Fig. 20 is partially a schematic exploded perspective view and partially a block diagram

of an ultrasonographic device or system related to the present invention.

Fig. 21 is a schematic perspective view showing use of the system of Fig. 20 in

performing a laparoscopic operation. Figs. 22 A and 22B are schematic perspective views showing use of another

ultrasonographic device related to the present invention.

Fig. 23 A is a schematic perspective view of a further ultrasonographic device related to

the present invention.

Fig. 23B is a schematic perspective view showing use of the ultrasonographic device of

Fig. 23A.

Fig. 24 is a schematic perspective view of an ultrasonographic device. Fig. 25 is a schematic perspective view of another ultrasonographic device.

Fig. 26 is a schematic perspective view of the ultrasonographic device of Fig. 25,

showing the device in use on a patient.

Fig. 27A is a schematic front elevational view of a video screen display configuration

utilizable in the ultrasonographic device of Figs. 25 and 26.

Fig. 27B is a schematic front elevational view of a further video screen display

configuration utilizable in the ultrasonographic device of Figs. 25 and 26.

Fig. 28 is a schematic partial perspective view of a modification of the ultrasonographic

device of Figs. 25 and 26, showing a mode of use of the device in a surgical treatment or a

diagnostic procedure.

Fig. 29 is partially a schematic perspective view and partially a block diagram of an

ultrasonic imaging system in accordance with the present invention.

Fig. 30 is a schematic perspective view, on a larger scale, of a modular transducer

package or array aperture included in the system of Fig. 29.

Fig. 31 is a diagram of two relative spaced and rotated modular transducer packages or

array apertures similar to that of Fig. 30, showing geometric parameters in a calculation of

relative position and orientation.

Fig. 32 is partially a schematic perspective view and partially a block diagram showing a

modification of the ultrasonic imaging system of Fig. 29.

Fig. 33 is a block diagram of components of a phased-array signal processing circuit

shown in Fig. 32, also showing components from Fig. 29. DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed chiefly to an imaging device and particularly to an

ultrasonographic imaging device utilizable in diagnostic and therapeutic procedures. The

ultrasonographic imaging device of the present invention is described generally hereinafter with

reference to Figs. 8 et seq. The ultrasonographic imaging device, and particularly image

derivation or construction portions thereof, can be employed as an image generating apparatus or

scanner 42 in the medical diagnostic system of Fig. 1 or a diagnostic image generating apparatus

78a, 78b, 78i in the medical diagnostic system of Fig. 4. Alternatively or additionally, the

ultrasonographic imaging device can be employed in carrying out certain minimally invasive

diagnostic or therapeutic operations, examples of which are illustrated schematically in Figs. 12

and 13.

As illustrated in Fig. 1, a medical diagnostic system comprises a device 20 for monitoring

and measuring a biological or physiological parameter. Monitoring and measuring device 20 is

juxtaposable to a patient for collecting individualized medical data about the patient's condition.

Device 20 may take the form of an electronic thermometer, an electronic blood pressure gauge, a

pulmonary function apparatus, a Doppler study apparatus, an EEG machine, an EKG machine, an

EMG machine, or a pressure measurement device, etc., or include a plurality of such

components.

Monitoring and measuring device 20 is connected at an output to a digitizer 22 which

converts normally analog type signals into coded binary pulses and transmits the resulting digital

measurement signal to a computer 24. Digitizer 22 may be incorporated into a housing (not shown) enclosing all or part of the monitoring and measuring device 20. Moreover, digitizer

may be an integral part of monitoring and measuring device 20.

Computer 24 receives instructions and additional input from a keyboard 26. Keyboard 26

is used to feed computer 24 information for identifying the patient, for example, the patient's age,

sex, weight, and known medical history and conditions. Such medical conditions may include

past diseases and genetic predispositions.

Computer 24 is also connected to an external memory 28 and an output device 30 such as

a printer or monitor. Memory 28 stores medical data for a multiplicity of previously diagnosed

medical conditions which are detectable by analysis of data provided by monitoring and

measuring device 20.

As illustrated in Fig. 2, monitoring and measuring device 20 detects a magnitude of a

predetermined biological or physiological parameter in a step 32. Digitizer 22 converts the

detected magnitude into a pre-established digital format in a step 34 and transmits the digital

signal to computer 24 in a step 36. Computer 24 is operated in a step 38 to compare the digitized

data from monitoring and measuring device 20 with the data stored in memory 28 and to derive a

diagnosis as to the patient's condition. The diagnosis is then communicated to the user (operator)

and to the patient via output device 30 in a step 40.

If monitoring and measuring device 20 measures a physiological function characterized

by a plurality of different variables, for example, the electric potential at different points on the

patient's body (EEG, EKG, EMG), these variables may be broken down by computer 24 into one

or more parameters, e.g., a frequency packet. The measured values of the pre-established parameters are then compared with parameter ranges stored in memory 28 for the type of

parameter and the kind of patient, as characterized by sex, age, weight, etc. If the measured

values of the pre-established parameters fall within expected ranges, as stored in memory 28,

then computer 28 communicates a "normalcy" finding via printer 30. If, on the contrary, the measured values of one or more parameters fall outside the normal ranges, then a diagnosis of a

possible medical condition is printed out.

As further illustrated in Fig. 1, the medical diagnostic system may comprise, in addition

to or alternatively to monitoring and measuring device 20, image generating apparatus or scanner 42 for generating in electrically encoded form a visually readable image of an organic part of the

patient. Scanner 42 may take the form of an MRI apparatus, a CAT scanner, an X-ray machine, an ultrasonography apparatus (see Figs. 8-15 and 20), or a video camera with or without

magnification optics for magnifying a sample on a slide. The video camera can be used for

obtaining an image of a portion of a patient's skin.

Scanner 42 is connected via an interface 44 to computer 24. As shown in Fig. 3, scanner 42 obtains an image of a tissue or organ in a step 46. The image is digitized, either by scanner 42 or interface 44 in a step 48, and is transmitted to computer 24 in a step 50. Computer 24 is operated in a step 52 to analyze the image from

scanner 42 and determine specific values for a multiplicity of predetermined parameters. For example, in the event that scanner 42 takes the particular form of a video camera for

dermatological diagnosis, an image of a skin surface of a patient is analyzed by computer 24 to derive such parameters as percentage of skin covered by abnormal condition, the range of sizes of individual ulcers, the range of color variation (e.g., whether bleeding is symptomatic).

The specific values of pre-established parameters calculated by computer 24 from

electrically encoded images transmitted from scanner 42 are compared by computer 24 with

previously determined parameter ranges stored in memory 28. For example, if a pregnant

woman's fetus is being scanned by ultrasonography, the lengths of the fetal appendages, arms,

legs, fingers, etc., are compared with each other and with respective fetal appendage ranges

recorded in memory 28 for the stage of pregnancy, weight of the fetus, and possibly weight of the

mother. In the event that any appendages are missing or are of abnormal length, a diagnosis as to

possible deformity is printed out. Organs internal to the fetus may be similarly examined

automatically by scanner 42 and computer 24. In more advanced stages of pregnancy,

physiological functions such as the heart rate of the fetus may be automatically monitored for

abnormal conditions.

The analysis performed by computer 24 on the image from scanner 42 will depend in part

on the region of the patient's body being scanned. If a woman's breast or a person's cortex is

being monitored for tumorous growths, computer 24 is programmed to separate the tissue image

into regions of different textures. The different textured regions are parameterized as to size,

shape and location and the derived parameters are compared to values in memory 30 to determine

the presence of a tumor. Additional analysis is undertaken to detect lines in an image which may

indicate the presence of an organic body.

A similar analysis is undertaken to evaluate a tissue specimen on a slide. The texture and

line scanning may be repeated at different magnification levels if, for example, the tissue sample is a slice of an organ wall. On a high magnification level, the texture and line analysis can serve

to detect microorganisms in blood.

Memory 28 may store entire images related to different diseases. For example, memory

may store images of skin conditions in the event that scanner 42 takes the form of a video camera

at a dermatological diagnosis and treatment facility. In a step 54 (Fig. 3), computer 24 compares

the image of a patient's skin with previously stored images in memory 28, for example, by

breaking down the current image into sections and overlaying the sections with sections of the

stored images, at variable magnification levels.

In the event that scanner 42 takes the form of an MRI apparatus, a CAT scanner or an

ultrasonographic scanner such as those described hereinafter with references to Figs. 8-15 and 20,

the images stored in memory 28 are of internal organic structures. In step 54 (Fig. 3), computer

24 compares images of a person's internal organs with previously stored organ images in memory

28. Computer 24 partitions the image from the MRI apparatus or CAT scanner into subareas and

overlays the subareas with sections of the stored images, at variable magnification levels.

In a final step 40 (Fig. 3), computer 24 communicates the results of its diagnostic

evaluation to a user or patient.

As illustrated in Fig. 4, a medical diagnostic system comprises a plurality of remote

automated diagnostic stations 60a and 60b connected via respective telecommunications links

62a and 62b to a central computer 64. Each diagnostic station 60a, 60b may take the form shown

in Fig. 1, local computer 24 communicating via link 62a, 62b with central computer 64.

Alternatively, each diagnostic station 60a, 60b may take the form shown in Fig. 4 and include a respective plurality of monitoring and measuring devices 66a, 66b, ... 66n operatively connected

to a local computer 68 via respective digitizer output units 70a, 70b, ... 70n. Computer 68 is fed

instructions and data from a keyboard 72 and communicates diagnostic results via a monitor 74

or printer 76. As discussed hereinabove with reference to monitoring and measuring device 20 of

Fig. 1, each monitoring and measuring device 66a, 66b, ... 66n is juxtaposable to a patient for

collecting individualized medical data about the patient's condition. Monitoring and measuring

devices 66a, 66b, ... 66n may respectively take the form of an electronic thermometer, an

electronic blood pressure gauge, a pulmonary function apparatus, a Doppler study apparatus, an

EEG machine, an EKG machine, an EMG machine, or a pressure measurement device, etc.

Digitizers 70a, 70b, ... 70n convert normally analog type signals into coded binary pulses

and transmit the resulting digital measurement signals to computer 68. Digitizers 70a, 70b, ...

70n may be incorporated into the housings or casing (not shown) enclosing all or part of the

respective monitoring and measuring devices 66a, 66b, ... 66n.

Keyboard 72 is used to feed computer 68 information for identifying the patient, for

example, the patient's age, sex, weight, and known medical history and conditions. Such medical

conditions may include past diseases and genetic predispositions.

As further illustrated in Fig. 4, a plurality of diagnostic image generating apparatuses or

scanners 78a, 78b, ... 78i are also connected to central computer 64 via respective hard-wired or

wireless telecommunications links 80a, 80b, ... 80i. Scanners 78a, 78b, ... 78i each generate in

electrically encoded form a visually readable image of an organic part of the patient. Scanners

78a, 78b, ... 78i may each take the form of an MRI apparatus, a CAT scanner, an X-ray machine, an ultrasonography apparatus (Figs. 8-15 and 20), or a video camera with or without

magnification optics for magnifying a sample on a slide.

Because of the enormous quantity of data necessary for storing images, central computer

64 is connected to a bank of memories 82 at a central storage and information processing facility

84. Diagnosis of patient conditions may be undertaken by central computer 64 alone or in

cooperation with local computers 24 or 68.

As illustrated in Fig. 5, local computers 24 and 68 transmit information to central

computer 64 in data packets or modules each include a first string of binary bits 86 representing

the transmitting station 60a, 60b, a second bit string 88 identifying the patient, a bit group 90

designating the parameter which is being transmitted, another bit group 92 coding the particular

measured value of the parameter, a set of bits 94 identifying the point on the patient at which the

measurement was taken, and another bit set 96 carrying the time and date of the measurement.

Other bit codes may be added as needed.

As shown in Fig. 6, a computerized slide scanning system comprises a slide carrier 100

mountable to a microscope stage and a slide positioning device 102 mechanically linked to the

slide carrier 100 for shifting the carrier along a path determined by a computer 104. Computer

104 may be connected to an optional transport or feed assembly 106 which delivers a series of

slides (not shown) successively to slide carrier 100 and removes the slides after scanning.

Computer 104 is also connected to an optical system 108 for modifying the magnification

power thereof between successive slide scanning phases. Light emerging from optical system

108 is focused thereby onto a charge coupled device ("CCD") 110 connected to computer 104 for feeding digitized video images thereto.

Computer 104 performs a line and texture analysis on the digitized image information

from CCD 110 to determine the presence of different organic structures and microorganisms.

The different textured regions are parameterized as to size, shape and location and the derived

parameters are compared to values in a memory to identify microscopic structures. The texture

and line scanning is repeated at different magnification levels.

Computer 104 may be connected to a keyboard 112, a printer 114, and a modem 16.

Modem 116 forms part of a telecommunications link for connecting computer 104 to a remote

data processing unit such as computer 64 in Fig. 4.

Image generating apparatus 42 in Fig. 1 may take the form of the computerized slide

scanning system of Fig. 6.

As shown in Fig. 7, a device for measuring a diagnostic parameter and transmitting the

measurement over the telephone lines comprises a monitoring and measuring device 118 which

may take the form, for example, of an electronic thermometer, an electronic blood pressure

gauge, a pulmonary function apparatus, a Doppler study apparatus, an EEG machine, an EKG

machine, an EMG machine, or a pressure measurement device, etc., or include a plurality of such

components. Monitoring and measuring device 118 is connected at an output to a digitizer 120

which in turn is coupled to a modulator 122. Modulator 122 modulates a carrier frequency from

a frequency generator 124 with the data arriving from monitoring and measuring device 118 via

digitizer 120 and transmits the modulated signal to an electroacoustic transducer 126 via an

amplifier 128. Transducer 126 is removably attachable via a mounting element 130 to the mouthpiece of a telephone handset (not shown) and generates a pressure wave signal which is

converted by a microphone in the handset mouthpiece back to an electrical signal for

transmission over the telephone lines. Of course, transducer 126 may be omitted and modulator

122 connected directly to a telephone line.

The system of Fig. 7 enables the transmission of specialized medical data directly over

the telephone lines to a central computer (e.g. computer 64 in Fig. 4) which utilizes the incoming

data to perform a diagnostic evaluation on the patient.

Monitoring and measuring device 118 may include traditional medical instrumentation

such as a stethoscope or modern devices such as a CCD.

Fig. 8 shows an ultrasonographic image generating apparatus which may be used in the

medical diagnostic system of Fig. 1 (see reference designation 42) or in the medical diagnostic

system of Fig. 4 (see reference designations 78a, 78b, ... 78i). As will be apparent from the

following descriptions, the ultrasonographic image generating apparatus utilizes ultrasonic

pressure waves to obtain three-dimensional structural information pertaining to a patient's

internal tissues and organs. As shown in Fig. 8, a flexible web 132 carries a plurality of

electromechanical transducers 134 particularly in the form of piezoelectric electroacoustic crystal

elements disposed in a substantially rectangular array. Transducers 134 are each connectable to

an ultrasonic signal generator 136 via a switching circuit or multiplexer 138. Switching circuit

138 is operated by a control unit 140 to connect transducers 134 to signal generator 136 in a

predetermined sequence, depending on the area of a patient's body which is being ultrasonically

scanned. The sequence in which transducers 134 are connected to signal generator 136 may include phase shifts or time delays to implement an electronic scan of the patient's internal

tissues, as discussed below with reference, for example, to Fig. 32.

Web 132 also carries a multiplicity of electromechanical, specifically acoustoelectric,

transducers particularly in the form of transducers or sensors 142 also arranged in a substantially

rectangular array. Sensors 142 are connected to a switching circuit 144 also operated by control

unit 140. An output of switching circuit 144 is connected to a sound or pressure wave analyzer

146 via an amplifier 148.

The sequence in which sensors 142 are connected to pressure wave analyzer 146 may be

such as to enable or facilitate an organization of sensor responses into predetermined groupings

defining respective data gathering apertures. The grouping of sensors 142 may be an instantaneous grouping, varied instant by instant pursuant to real-time imaging requirements. Generally, the larger the apertures (the larger the areas of the respective groupings), the higher the resolution of the three-dimensional ("3D") volumetric data acquisition and of the imaging of

the ultrasonographic system. Where the outputs of sensors 142 are sampled or interrogated in groups so as to form a plurality of data gathering apertures, control unit 140 includes coherent aperture combining circuitry (See Fig. 29) for coherently combining structural data from the

respective apertures. In this case, position determination circuitry in control unit 140 and or

sound analyzer 146 executes computations according to a self-cohering algorithm that computes the relative positions and orientations of the data gathering apertures using instantaneous position measurements and adjusts the signals from the coherently combined apertures so they can be added together constructively. The resultant effective increase in total aperture size improves the resolution capability of the imaging system. Electronic scanning performed by

each data gathering aperture also requires position determination circuitry that computes the

relative positions of the sensors 142 themselves (since they are contained in a flexible web).

Control unit 140 may also include the option of noncoherently combining structural data, which

allows extended images to be created without increasing the imaging resolution.

The sequence in which sensors 142 are connected to analyzer 146 by switching circuit or

multiplexer 144 may include phase shifts or time delays to implement an electronic scan of the

patient's internal tissues, as discussed below.

Electroacoustic transducers 134 and sensors 142 may be implemented in the form of

packaged modular arrays of piezoelectric crystals, as discussed hereinafter with reference to Fig.

29. At the present time, such packages are generally linear arrays of some one hundred or more

piezoelectric crystal elements. Some modified linear arrays contain several linear arrays so that a

transverse or width dimension has up to ten crystal elements.

Fig. 8 shows electroacoustic transducers 134 and sensors 142 as being separate, so that

they perform dedicated generating (i.e., transmitting) and receiving functions, respectively. It is

also possible, however, to provide a multiplicity of piezoelectric electromechanical transducers or

arrays of transducer elements which perform both the transmitting and the receiving functions.

Various combinations of functions are also possible. For example, some transducer arrays may

function as both transmitters and receivers, while other transducer arrays function only as

receivers. The various operating potentialities are discussed in greater detail below with

reference to Fig. 29. Web 132 is draped over or placed around a portion of a patient's body which is to be

monitored ultrasonically. Control unit 140 then energizes signal generator 136 and operates

switching circuit 138 to activate transducers 134 in a predetermined sequence. Each transducer

134 may be a multiple-element aperture. In that case, several piezoelectric elements or scalar

excitation transducers are energized simultaneously with theexcitation waveform where

appropriate phases shifts or time delays are applied to effectuate electronic scanning. Depending

on the transducer or combination of transducers 134 which are activated, control unit 140

operates switching circuit 144 to connect a predetermined sequence of sensors 142 to pressure

wave analyzer 146. Again, each sensor 142 may be a multiple-element aperture, whereby a

plurality of piezeoelectric crystals are monitored simultaneously to receive a reflected pressure

waveform. Pressure wave analyzer 146 and control unit 140 cofunction to provide electronic 3D

volumetric data acquisition and to determine three dimensional structural shapes from the echoes

detected by sensors 142.

Control unit 140 is connected to ultrasonic signal generator 136 for varying the frequency

of the generated signal. Generally, the higher the frequency, the greater the penetration into

organic tissues for focusing purposes. Thus, a range of frequencies is useful for obtaining

sufficient data to construct electrically or digitally encoded three-dimensional models of internal

tissue and organ structures of a patient.

Fig. 9 shows a modified ultrasonography web 150 having a limited number of

electromechanical or electroacoustic transducers 152 and generally the same number and

disposition of electromechanical or acoustoelectric sensors 154 as in web 132. Web 132 or 150 may be substantially smaller than illustrated and may corresponding

carry reduced numbers of transducers 134 and 152 and sensors 142 and 154. Specifically, web

132 or 150, instead of being a sheet large enough to wrap around a torso or arm of a patient, may

take a strip-like form which is periodically moved during use to different, predetermined

locations on the patient. Control unit 140 and pressure wave analyzer 146 are programmed to

detect internal organic structures from the data obtained at the different locations that the web

132 or 150 is juxtaposed to the patient.

Fig. 10 illustrates a modification of the ultrasonography apparatus of Figs. 8 and 9 which

is employable in diagnostic or therapeutic operations involving the insertion of an instrument into

a patient. A control unit 156 for performing operations of control unit 140 is connected at an

output to a video monitor 158. As discussed hereinafter with reference to Figs. 12 and 13, a

diagnostician, surgeon or other medical specialist inserts a distal end of a medical instrument into

a patient in response to video feedback provided by the ultrasonography apparatus including

video monitor 158.

As further illustrated in Fig. 10, an a-c current or ultrasonic signal generator 160 is

connected via a multiplexer or switching circuit 162 to different piezoelectric type

electroacoustic transducers 164 in seriatim. Transducers 164 are mounted in interspaced fashion

to a flexible web 166 which also carries an array of spaced piezoelectric type acoustoelectric transducers 168.

Web 166 is placed adjacent to a skin surface of a patient. In some cases, with any of the

ultrasonic sensing devices described herein, it may be beneficial to provide a layer of fluid (e.g., water, gel) between the skin surface of the patient and the respective transducer carrier (e.g., web

166) to facilitate ultrasonic wave transmission from the electroacoustic transducers to the patient

and from the patient back to the acoustoelectric transducers or sensors. In some specific

embodiments of an ultrasonic imaging device discussed herein, a fluid-filled bag is used to

optimize pressure wave transmission between a transducer carrier and a skin surface of a patient.

Another kind of interface facilitating ultrasonic wave conduction is a moldable solid or semisolid

such as wave-conductive plastic material, known in the art.

In response to the periodic energization of transducers 164, ultrasonic pressure waves are

reflected from internal organic structures of the patient and sensed by acoustoelectric transducers

168. Electrical signals generated by transducers 168 in response to the reflected pressure waves

are fed via a multiplexer or switching circuit 170 to control unit 156.

As discussed hereinabove with reference to control unit 140 in Fig. 8, control unit 156

controls switching circuits 162 and 170 to energize emitting transducers 164 in a predetermined

sequence and to selectively couple receiving transducers 168 in a pre-established sequence to a

pressure wave or ultrasonic frequency analyzer 172 in control unit 156. The sequencing depends

in part on the portion of the patient being monitored.

As further discussed above with reference to Fig. 8, the sequence in which receiving

transducers 168 are sampled or interrogated by switching circuit 170 may organize sensor

response into predetermined groupings defining respective data gathering apertures. Control unit

156 and particularly ultrasonic frequency analyzer 172 thereof operates to coherently combine

structural data from the respective apertures, with the execution of a self-cohering algorithm which computes the relative positions and orientations of receiving transducers 168 (or data

gathering apertures) using instantaneous position measurements and which adjusts the signals

from the coherently combined apertures so they can be added together constructively. The

sequencing of transducer energization or excitation, as well as the sampling of outputs of sensors,

may also be carried out to execute a phased-array-type electronic scan of internal tissues.

In addition to pressure wave or ultrasonic frequency analyzer 172, control unit 156

includes a view selector 174 and a filter stage 176. View selector 174 is operatively connected at

an input to analyzer 172 and at an output to video monitor 158 for selecting an image for display

from among a multiplicity of possible images of the internal organs detected by analyzer 172.

View selector 174 may be provided with an input 178 from a keyboard (not shown) or other

operator interface device for enabling an operator to select a desired view. For example, during

the insertion of a medical diagnostic or treatment instrument into the patient or during

manipulation of that instrument to effect an operation on a targeted internal organ of the patient,

the medical practitioner may sequentially select views from different angles to optimize the

practitioner's perception of the spatial relation between the distal tip of the instrument and the

patient's internal organs.

Filter stage 176 is operatively connected to analyzer 172 and video monitor 158 for

optionally eliminating a selected organ from the displayed image. Filter stage 176 is provided

with an input 180 from a keyboard (not shown) or other operator interface device for enabling an

operator to select an organ for deletion from the displayed image. In one example of the use of

filter stage 176, blood moving through a vessel of the vascular system is deleted to enable viewing of the blood vessel walls on monitor 158. This deletion is easily effected starting from

conventional techniques such as the Doppler detection of moving bodies.

Filter stage 176 may also function to highlight selected organs. The pattern recognition

techniques discussed above are used to detect selected organs. The highlighting may be

implemented exemplarily through color, intensity, cross-hatching, or outlines.

As further illustrated in Fig. 10, control unit 156 is optionally connected at an output to a

frame grabber 182 for selecting a particular image for reproduction in a fixed hard copy via a

printer 184. In addition, as discussed hereinabove with respect to the telecommunications links

80a, 80b ... 80i in Fig. 4, ultrasonically derived real-time image information may be encoded by a

modulator 186 onto a carrier wave sent to a remote location via a wireless transmitter 188.

Fig. 11 depicts the ultrasonography apparatus of Fig. 10 in a form wherein control unit

156 (Fig. 10) is realized as a specially programmed general purpose digital computer 190. A

switching circuit or multiplexer 192 relays signals incoming from respective acoustoelectric

transducers 168 (Fig. 10) in a predetermined intercalated sequence to an analog-to-digital

converter 194, the output of which is stored in a computer memory 196 by a sampling circuit 198

of computer 190. A wave analysis module 200 of computer 190 retrieves the digital data from

memory 196 and processes the data to determine three dimensional organic structures inside a

patient. This three-dimensional structural data is provided to a view selection module 202 for

deriving two-dimensional images for display on monitor 158 (Fig. 10). A filter module 204 is

provided for removing selected organs from the image presented on the visual display or video

monitor 158. Sampling circuit 198, wave analysis module 200, view selection module 202, and filter module 204 are program-modified generic digital circuits of computer 190.

Fig. 12 shows a use of a flexible ultrasonic sensor web 206 which may be any of the

flexible ultrasonic sensor webs described herein, except that web 206 is additionally provided with a plurality of apertures or perforations 208. Upon the placement of web 206 in pressure-

wave transmitting contact with a skin surface of a patient P, elongate diagnostic or therapeutic

instruments such as laparoscopic surgical instruments 210 and 212 are inserted through

respective openings 208 to perform a surgical operation on a designated internal organ of the

patient PI . This operation is effectuated by viewing a real time image of the distal ends of the

instruments 210 and 212 in relation to the patient's internal organic structures as determined by

control unit 156 or computer 190. Generally, the image on monitor 158 is viewed during insertion of instruments 210 and 212 to enable a proper employment of those instruments. Also, the video images on monitor 158 are viewed to enable a proper carrying out of the "laparoscopic"

surgical operation on the designated internal organ of the patient PI . Strictly speaking, this operation is not a laparoscopic operation, since a laparoscope is not used to provide a continuing image of the patient's internal organic structures and the distal ends of instruments 210 and 212.

There are multiple advantages to using sonographic web 206 instead of a laparoscope.

Fewer perforations need be made in the patient for the same number of surgical instruments. In

addition, multiple views of the patient's internal organic structures are possible, rather than a single view through a laparoscope. Generally, these multiple views may differ from one another

by as little as a few degrees of arc. Also, particularly if web 206 is extended essentially around patient PI, viewing angles may be from under the patient where a laparoscopic could not realistically be inserted.

Web 206 may be used to insert tubular instruments such as catheters and drainage tubes,

for example, for thoracentesis and abscess drainage. The tubes or catheters are inserted through

apertures 208 under direct real time observation via monitor 158. In addition to treatment, web 206 may be used to effectuate diagnostic investigations. In

particular, a biopsy instrument 214 may be inserted through an aperture 208 to perform a breast

biopsy, a liver biopsy, a kidney biopsy, or a pleural biopsy.

As illustrated in Fig. 13, a flexible ultrasonic sensor web 216, which may be any of the

flexible ultrasonic sensor webs described herein, may be used in a diagnostic or therapeutic

operation utilizing a flexible endoscope-like instrument 218. Instrument 218 has a steering control 220 for changing the orientation of a distal tip 222 of the instrument. Instrument 218 also has a port 224 connected to an irrigant source 226 and another port 228 connected to a suction source. In addition, instrument 218 is provided a biopsy channel (not shown) through which an

elongate flexible biopsy instrument or surgical instrument 230 is inserted. Instrument 218 is considerably simplified over a conventional endoscope in that instrument 218 does not require fiber-optic light guides for carrying light energy into a patient P2 and image information out of the patient. Instead, visualization of the internal tissues and organ structures of patient P2 is effectuated via monitor 158 and control unit 156 or computer 190. As discussed above with reference to Fig. 12, the sonographic imaging apparatus if web 216 is extended essentially around patient P2, images may be provided from multiple angles, not

merely from the distal tip 222 of instrument 218. View selector 174 and organ filter stage 176 or view selection module 202 and filter

module 204 may function in further ways to facilitate viewing of internal organic structures. In

addition to organ removal and highlighting, discussed above, a zoom capability may be provided.

The zoom or magnification factor is limited only by the resolution of the imaging, which is

determined in part by the frequency of the ultrasonic pressure waves. The resolution of the

imaging is also determined by the sizes of various transducer arrays which function together as

single apertures. Generally, the larger the array, or the more transducers which are energized or

sampled synchronously, then the higher the resolution. As discussed hereinafter with reference

to Fig. 29 et seq., coherent aperture combining is used to increase the sizes of the transducer

array apertures, thereby maximizing image resolution.

Figs. 14 and 15 depict a specialized ultrasonic sensor web 232 in the form of a garment

such as a vest. Sensor vest 232 has arm holes 234 and 236, a neck opening 238 and fasteners 240

for closing the vest about a patient. In addition, sensor vest 232 is provided with a plurality of

elongate chambers 242 which receive fluid for expanding the vest into conformation with a

patient's skin surface, thereby ensuring contact of the vest with a patient's skin surface and

facilitating the transmission of ultrasonic pressure waves to and from ultrasonic transducers 244.

Fig. 14 shows a computer 246, a video monitor 248 and a printer 250 used as described above.

Sensor vest 232 may be understood as a container assembly having fluid-filled chambers

242 with flexible inwardly facing walls (not separately designated) which conform to the patient.

Sensor vest 232 may additionally be provided along an inner side with a conventional interface

medium, whether water, gel, plastic or some other material, which is conducive to the transmission of ultrasonic vibrations across the interface between the patient and the sensor vest.

As illustrated in Fig. 16, an ultrasonography apparatus comprises a container assembly

302 including a substantially rigid plate 304 attached to a flexible bladder or bag 306. Bladder or

bag 306 is filled with a liquid and is sufficiently flexible to substantially conform to a patient

when the container assembly 302 is placed onto a patient PTl, as illustrated in Fig. 17. A liquid

or gel or other interface medium may be deposited on the patient prior to the placement of

container assembly 302 on patient PTl.

Plate 304 is provided with multiple ultrasonic pressure wave generators and receivers 308

as described above with respect to Figs. 8 and 9 and Figs. 14 and 15. Generators and receivers

308 are connected to a computer 310 having essentially the same functional structures and

programming as computer 190 for implementing sequential generator energization and sequential

receiver sampling, as described above. Computer 310 is connected to a monitor 312 for

displaying images of internal organs of patient PTl. Computer 310 has the capability of

alternately displaying organ images from different angles, as discussed above.

Ultrasonic pressure wave generators and receivers 308 may be densely packed and

energized or interrogated as individual elements separately from each other. Coherent aperture

combining is not used in such an operating mode. Alternatively, the ultrasonic pressure wave

receivers 308 may be sampled or interrogated in groups, permitting the formation of a plurality of

data gathering apertures. In that case, computer 310 may coherently combine structural data

from the different apertures to thereby increase focusing power or resolution.

Plate 304 may be formed as a rectangular array of rigid modular substrates rigidly connected to one another, each of the substrates holding a plurality of the transducers. The

modular substrates are off-the-shelf components such as the 1.5D transducer arrays found in

conventional, premium probes, with on the order of 100 piezoelectric transducers (or elements)

disposed in a tightly packed line along a length dimension of the substrate. Inter-element spacing

is typically one wavelength or less to support full scanning along the length dimension. A width

dimension of a modular substrate carries substantially fewer (e.g. less than 10) piezoelectric

transducers. Inter-element spacing along the width dimension is typically a few or several

wavelengths. The electronic scanning of internal tissue structures of a patient along the length

dimension is performed conventionally by computer 310. Computer 310 also provides

present invention which is described in detail hereinafter.

Fig. 18 depicts another ultrasonography apparatus useful for both diagnostic

investigations and minimally invasive surgical operations. The apparatus comprises a container

assembly 314 which includes a fluid-filled sack or bag 316 for receiving a patient PT2. Sack or

bag 316 includes a flexible upper wall 318 which deforms to conform to the patient PT2 upon

placement of the patient onto the bag. Bag 316 is supported on two or more sides by

substantially rigid walls or panels 320 and 322. Panels 320 and 322 are either integral with bag

316 or separable therefrom. Panels 320 and 322, as well as an interconnecting bottom panel 324,

may be provided with multiple ultrasonic pressure wave generators and receivers (not shown) as

described above with respect to Figs. 8 and 9, Figs. 14 and 15, and Fig . 16. These generators and receivers are connected to a computer 326 having essentially the same functional structures

and programming as computer 190 for implementing sequential generator energization and

sequential receiver sampling, as described above. Computer 326 is connected to a monitor 328

for displaying images of internal organs of patient PT2. Computer 326 has the capability of

alternately displaying organ images from different angles, as discussed above.

The ultrasonic pressure wave generators and receivers may be disposed in a wall panel of

bag 316 or may be provided in a separate carrier 330 disposable, for example, between bottom

panel 324 and bag 316, as shown in Fig. 18.

Where the ultrasonic pressure wave generators and'receivers may be densely packed and

receivers may be sampled or interrogated in groups, permitting the formation of a plurality of

data gathering apertures. In that case, computer 326 may coherently combine structural data

from the different apertures to thereby increase focusing power or resolution.

As illustrated in Fig. 19, the ultrasonography apparatus of Fig. 19 may be used in

conjunction with a flexible web or cover sheet 332 identical to web 132, 150, or 206 (Fig. 8, 9, or

12). Web or cover sheet 332 is operatively connected to computer 326 for providing

ultrasonically derived organ position and configuration data to the computer for displaying organ

images on monitor 328. The use of web or sheet 332 enables the disposition of ultrasonic wave

generators and receivers in a 360 arc about a patient PT3 (diagrammatically illustrated in Fig,.

19), thereby facilitating image production. Where web or sheet 332 takes the form of web 206, the sheet is provided with apertures (see Fig. 12 and associated description) for enabling the

introduction of minimally invasive surgical instruments into the patient PT3.

As discussed above, to contact surfaces a liquid, gel or other conductive medium is

applied to facilitate ultrasonic pressure wave transmission over interfaces.

As discussed hereinafter with reference to Fig. 20, video monitor 158 (Figs. 10, 12, and

13) or monitor 328 (Fig. 19) may take the form of a flexible video screen layer attached to web

132, 150, 166 or 206 (Fig. 8, 9, 10, 12) or web 332 (Fig. 19). This modification of the

ultrasonographic imaging devices discussed above is considered to be particularly advantageous

in medical diagnosis and treatment procedures. The web or substrate with the video screen is

disposed on a selected body portion of a patient, for example, the abdomen (Figs. 12 and 21) or a

shoulder (Figs. 22A, 22B) or knee (Fig. 23B), so that the substrate and the video screen layer

substantially conform to the selected body portion and so that the video screen is facing away

from the body portion.

As shown in Fig. 20, an ultrasonographic device or system comprises a flexible substrate

or web 350 which carries a plurality of piezoelectric electroacoustic transducers 352 and a

plurality of piezoelectric acoustoelectric transducers (or receivers) 354. A flexible video screen

356 is attached to substrate or web 350 substantially coextensively therewith. Video screen 356

may be implemented by a plurality of laser diodes (not shown) mounted in a planar array to a

flexible carrier layer (not separately designated). The diodes are protected by a cover sheet (not

separately illustrated) which is connected to the carrier layer. Energization componentry is

operatively connected to the diodes for energizing the diodes in accordance with an incoming video signal to reproduce an image embodied in the video signal. In a video monitor, the laser

diodes are tuned to different frequency ranges, so as to reproduce the image in color. The

protective cover sheet may function also to disperse light emitted by the laser diodes, to generate

a more continuous image.

Substrate or web 350 and video screen 356 comprise an ultrasonic video coverlet or

blanket 358 which may be used with the control hardware depicted in Figs. 10 and 11. Reference

numerals used in Figs. 10 and 11 are repeated in Fig. 20 to designate the same functional

components.

Electroacoustic transducers 352 are connected to a-c or ultrasonic signal generator 160 for

receiving respective a-c signals of variable frequencies. Generator 160 produces frequencies

which are directed to the electroacoustic transducers 352 by switching circuit 162. Pressure

waveforms of different ultrasonic frequencies have different penetration depths and resolutions

and provide enhanced amounts of information to a digital signal processor or computer 360. As

discussed above with reference to computer 190 of Fig. 11, computer 360 is a specially

programmed digital computer wherein functional modules are realized as generic digital

processor circuits operating pursuant to preprogrammed instructions.

As discussed above with reference to Fig. 11, switching circuit or multiplexer 192 relays

signals incoming from respective acoustoelectric transducers 354 in a predetermined intercalated

sequence to analog-to-digital converter 1 4, the output of which is stored in computer memory

196 by sampling circuit 198. Acoustoelectric transducers 354 may be interrogated by

multiplexer 192 and sampling circuit 198 in such a sequence as to enable or facilitate a grouping of transducers 354 to form a plurality of data gathering apertures. Waveform analysis module

200 retrieves the digital 3D volumetric data from memory 196 and processes the data acquired

from the internal tissue structures, thereby determining three dimensional organic structures

inside a patient. Waveform analysis module 200 includes coherent aperture combining circuitry

(see Fig. 29) for coherently combining structural data from the respective apertures. Wave

analysis module 200 also includes position determination circuitry which executes computations

according to a self-cohering algorithm that computes the relative positions and orientations of the

respective apertures using instantaneous position measurements and adjusts the signals from the

coherently combined apertures so they can be added together constructively. Analysis module

200 may also include the option of noncoherently combining structural data, which allows

extended images to be created without increasing the imaging resolution.

The three-dimensional structural data generated by waveform analysis module 200 is

provided to view selection module 202 for deriving two-dimensional images for display on video

screen 256. Filter module 204 serves to remove selected organs, for example, overlying organs,

from the image presented on video screen 356. Sampling circuit 198, wave analysis module 200,

view selection module 202, and filter module 204 are program-modified generic digital circuits

of Computer 360.

Computer 360 contains additional functional modules, for example, an organ highlighter

362 and a supeφosition module 364. The functions of organ highlighter 362 are discussed above

with reference to organ filter 176 and 204 in Figs. 10 and 11. Organ highlighter 362 operates to

provide a different color or intensity or cross-hatching to different parts of an image to highlight a selected image feature. For example, a gall bladder or an appendix may be shown with greater

contrast than surrounding organs, thereby facilitating perception of the highlighted organ on

video screen 356. After organ filter 204 has removed one or more selected organs from an

electronic signal representing or encoding an image of internal organs, highlighter 362 operates

to highlight one or more features of the encoded image.

Supeφosition module 364 effects the insertion of words or other symbols on the image

displayed on video screen 356. Such words or symbols may, for example, be a diagnosis or alert

signal produced by a message generator module 366 of computer 360 in response to a diagnosis

automatically performed by a determination module 368 of computer 360. Module 368 receives the processed image information from waveform analysis module 200 and consults an internal memory 370 in a comparison or pattern recognition procedure to determine whether any organ or internal tissue structure of a patient has an abnormal configuration. The detection of such an

abnormal configuration may be communicated to the physician by selectively removing organs,

by highlighting organs or tissues, or superimposing an alphanumeric message on the displayed

image. Accordingly, message generator 366 may be connected to organ filter 204 and organ highlighter 362, as well as to supeφosition module 364. The communication of an abnormal condition may be alternatively or additionally effectuated by printing a message via a printer 372 or producing an audible message via a speech synthesis circuit 374 and a speaker 376.

As discussed above, the ultrasonically derived three-dimensional structural information from waveform analysis module 200 may be transmitted over a telecommunications link (not shown in Fig. 20) via a modulator 378 and a transmitter 380. The transmitted information may be processed at a remote location, either by a physician or a computer, to generate a diagnosis.

This diagnosis may be encoded in an electrical signal and transmitted from the remote location to

a receiver 382. Receiver 382 is coupled with message generator module 366, which can

communicate the diagnosis or other message as discussed above.

Computer 360 is connected at an output to a video signal generator 384 (which may be

incoφorated into the computer). Video signal generator 384 inserts horizontal and vertical

synchronization signals and transmits the video signal to video screen 356 for displaying an

image of internal patient organs thereon.

Fig. 21 diagrammatically depicts a step in a "laparoscopic" cholecystectomy procedure utilizing the ultrasonographic device or system of Fig. 20. Coverlet or blanket 358 is disposed on the abdomen of a patient P2 in pressure- wave transmitting contact with the skin. The skin is

advantageously wetted with liquid to facilitate ultrasonic pressure wave transmission. Laparoscopic surgical instruments 210 and 212 (same as in Fig 12) are inserted through

respective openings 386 in coverlet or blanket 358 to perform a surgical operation on a gall bladder GB of the patient P2. This operation is effectuated by viewing a real time image of the

distal ends of the instruments 210 and 212 in relation to the patient's internal organic structures as determined by computer 360. Generally, the image on video screen 356 is viewed during insertion of instruments 210 and 212 to enable a proper employment of those instruments.

As illustrated in Fig. 21, the gall bladder GB is highlighted (e.g., with greater contrast in screen intensities) relative to other organs such as the liver LV, the stomach ST and the large intestine LI. One or more of these organs may be deleted entirely by organ filter 204. Computer 360 is instructed as to the desired display features via a keyboard (not illustrated in Fig. 20) or a

voice recognition circuit 388 operatively connected to various modules 202, 204 and 362. (It is

to be noted that speech synthesis circuit 374 and voice recognition circuit 388 enable computer

360 to carry on a conversation with a user. Thus the user may direct the computer to answer

questions about the appearance of certain organs selected by the user.

Generally, the images of the different organs GB, LV, ST and LI, etc., are displayed on

video screen 356 so as to substantially overlie the actual organs of the patient P2. To effectuate

this alignment of image and organ, markers 390, 392, 394 are placed on the patient P2 at

appropriate identifiable locations such as the xyphoid, the umbilicus, the pubis, etc. The markers

are of a shape and material which are easily detected by ultrasonic wave analysis and provide

computer 360 with a reference frame for enabling the alignment of organ images on screen 356

with the corresponding actual organs. During an operation, view selector 202 may be utilized

^■ (via keyboard command or voice recognition circuit 388) to adjust the relative positions of image

and organs to facilitate the performance of an invasive surgical operation. As discussed above

with reference, for example, to Fig.-13, the ultrasonographic device or system of Fig. 20 may be

used in other kinds of procedures.

As illustrated in Fig. 22A, an ultrasonographic coverlet or blanket 396 with attached

video screen (not separately designated) and connected computer 398 has a predefined shape

conforming to a shoulder SH. The coverlet or blanket 396 is flexible and thus deforms upon

motion of the shoulder (Fig. 22B). The coverlet or blanket 396 has a memory so that it returns to

the predefined shape when it is removed from the shoulder SH. The flexibility of the coverlet or * blanket 396 enables the display in real time of a filtered video image showing the shoulder joint

SJ during motion of the shoulder. This facilitates a diagnostic appraisal of the joint.

Fig. 23 A illustrates an ultrasonic video cuff 400 with a computer 402. The cuff is

attachable in pressure- wave transmitting contact to a knee KN, as depicted in Fig. 23B. Cuff 400

conforms to the knee KN and follows the knee during motion thereof. A knee joint KJ is imaged

on the cuff during motion of the knee KN, thereby enabling a physician to study the joint

structure and function during motion. Cuff 400 has a memory and returns to its predefined shape

(Fig. 23 A) after removal from knee KN.

Video screen 356, as well as other video monitors disclosed herein, may be a lenticular

lens video display for presenting a stereographic image to a viewer. The ultrasonic processor,

e.g., computer 190 or 360, operates to display a three-dimensional image of the internal organs

on the lenticular lens video display. 118. Because of the stereoscopic visual input a surgeon is

provided via video display 356, he or she is better able to manipulate instruments 210 and 212

during a surgical procedure.

Electroacoustic transducers 134, 164, 352 in an ulfrasonographic coverlet or blanket 132,

166, 206, 216, 358 as described herein may be used in a therapeutic mode to dissolve clot in the

vascular system. The coverlet or blanket is wrapped around the relevant body part of a patient so

that the electroacoustic transducers surround a target vein or artery. First, a scan is effectuated to

determine the location of the clot. Then, in a clot dissolution step, the electroacoustic transducers

are energized to produce ultrasonic pressure waves of frequencies selected to penetrate to the

location of the clot. With a sufficiently large number of transducers transmitting waves to the clot site simultaneously, the clot is disrupted and forced away from the clot site. It is

recommended that a filter basket be placed in the pertinent blood vessels downstream of the clot

site to prevent any large clot masses from being swept into the brain or the lungs where an

embolism would be dangerous.

The monitors disclosed herein, such as monitors 158, 248, 312, 328 and video screen 356,

may be provided with a lenticular lens array (not shown) for generating a three-dimensional or

stereoscopic display image when provided with a suitable dual video signal. Such a dual signal

may be generated by the waveform analysis computer 190, 310, 326, 360 with appropriate

programming for the view selection module 202 to select two vantage points spaced by an

appropriate distance. Lenticular lens video displays, as well as the operation thereof with input

from two cameras, are disclosed in several U.S. patents, including U.S. Patent No. 4,214,257 to

Yamauchi and U.S. Patent No. 4,164,748 to Nagata, the disclosures of which are hereby

incoφorated by reference.

It is to be noted that any of the ultrasonography devices or systems disclosed herein may

be used in a robotic surgical procedure wherein one or more surgeons are at a remote location

relative to the patient. The performance of robotic surgery under the control of the distant

experts is disclosed in U.S. Patents Nos. 5,217,003 and 5,217,453 to Wilk, the disclosures of

which are hereby incoφorated by reference. Video signals transmitted to the remote location

may be generated by the analysis of ultrasonic waves as disclosed herein.

The ultrasonography devices or systems disclosed herein may be used in conjunction with

other kinds of scanning devices, for example, spectral diagnosis and treatment devices described in U.S. Patents Nos. 5,305,748 to Wilk and 5,482,041 to Wilk et al. (those disclosures

incoφorated by reference herein). It may be possible to incoφorate the electromagnetic wave

generators and sensors of those spectral diagnosis and treatment devices into the coverlet or

blanket of the present invention.

As illustrated in Fig. 24, a medical imaging device comprises a planar firm substrate 404,

a substantially flat video screen 406 provided on the substrate, and a flexible bag 408 connected

to the substrate. Flexible bag 408 contains a fluidic medium such as water or gel capable of

transmitting pressure waves of ultrasonic frequencies and is disposed on a side of the substrate

opposite the video screen. Alternatively and equivalently, bag 408 may be a substantially solid

mass of a deformable material conducive to the transmission of ultrasonic pressure waves.

Certain plastic or polymeric materials known in the art would be suitable for such an application.

As discussed above, a scanner 410 including an ultrasonic waveform generator 412 and a

computer-implemented ultrasonic signal processor 414 are operatively connected to video screen

406 for providing a video signal thereto. The video signal encodes an image of internal tissues of

a patient PT4 upon placement of medium-containing bag 408, subsfrate 404, and video screen

406 against the patient. The images of internal tissues and organs off the patient, including the

stomach SH, the heart HT, the lungs LG, the small intestine SE, and the large intestine LE, are

displayed on screen 406 at positions generally overlying the respective actual tissues and organs

of the patient PT4.

Video screen 406 and subsfrate 404 may be provided with aligned apertures 415 for

enabling the traversal of the video screen and the substrate by medical instruments as discussed above with reference to Fig. 21.

Figs. 25 and 26 show another medical imaging device comprising a flexible bag 416

containing a fluidic medium such as water or gel. A multiplicity of substantially rigid planar

substrates or carrier pads 418 together with respective flat video screens 420 attached thereto are

mounted to an upper surface of bag 416. Bag 416 serves in part to movably mount pads 418 with

their respective video screens 420 to one another so that the orientations or relative angles of the

video screen can be adjusted to conform to a curving surface of a patient PT5, as shown in Fig.

26. Again, a scanner 422 including an ultrasonic waveform generator 424 and a computer-

implemented ultrasonic signal processor 426 is operatively connected to video screens 420 for

providing respective video signals thereto. The video signals encode respective images of

internal tissues of a patient PT5 upon placement of medium-containing bag 416, substrates 418

and video screens 420 against the patient. As illustrated in Fig. 27 A, the video images displayed

on screen 420 may be substantially the same, with differences in the angle of view of a target

organ ORG, depending on the locations and orientations of the respective screens 420.

Alternatively, in an enlarged view, a single image of the target organ ORG may be displayed,

with each screen 420 displaying only a part of the total image. The technology for implementing

these displays over video screens 420 is conventional and well known.

Scanners 410 and 422 are ultrasonic scanners with the same components as other

ultrasonic scanners discussed herein,- for example, with reference to Fig. 21. Briefly, scanners

410 and 422 each includes a plurality of electroacoustic transducers and a plurality of

acoustoelectric transducers disposed in respective arrays in the respective bag 408 or 416 or on substrates 404 and 418 so that ultrasonic pressure waves can travel through the fluidic medium in

the respective bag from the electroacoustic transducers and to the acoustoelectric transducers.

Computers or processors 414 and 426 analyze incoming digitized ultrasonic sensor signals which

are produced in response to ultrasonic pressure waves reflected from various tissue interfaces in

the patient PT4 or PT5. From these incoming ultrasonic sensor signals, computers or processors

414 and 426 determine three-dimensional shapes of tissue interfaces and organs inside the patient

PT4 or PT5.

Accordingly, scanners 410 and 422 include electromechanical transducers, specifically

electroacoustic and acoustoelectric transducers (neither shown), as discussed herein for

generating ultrasonic pressure waves and receiving or detecting reflected pressure waves as

discussed hereinabove. The transducers may be mounted to carrier plates or substrates 404 and

418, maybe incoφorated into flexible bags 408 and 416, or may be disposed in carrier panels

underlying the patient as described hereinabove with reference to Figs.18 and 19. As discussed

below with reference to Figs. 29 et seq., the transducers are possibly incoφorated into rigid

arrays functioning as respective apertures whose signal outputs may be coherently combined to

maximize resolution.

The transducers of scanners 410 and 422 may be densely packed in both length and width

dimensions using inter-element spacings, in both the length and width dimensions, of a

wavelength or less to support full 2D scanning. Alternatively, presently available, off-the-shelf

ID or 1.5D array technology may be used. Processors 414 and 426 may organize the transducers

contained within substrates 404 and 418 into groups or data gathering apertures and coherently combine structural data from the apertures, using CAC, to enhance the attainable resolution. A

self-cohering algorithm is not needed in this case since all aperture locations and orientations are

known. Within each data gathering aperture, electronic scanning is effectuated to interrogate

tissue structures. For the case where data gathering apertures are to be combined from different

substrates, a self-cohering algorithm is needed to process the data from the respective apertures

in the embodiment of Figs. 25 and 26.

As discussed above with reference to Fig. 21, it is recommended that markers be placed

in prespecified locations on the patient to enable or facilitate an alignment of the displayed tissue

representations and the respective underlying actual tissues. The markers are easily recognized

by computer 426 and serve to define a reference frame whereby the positions and the orientations

of the multiple video screens 420 relative to the patient's internal tissues are detectable. Thus,

the position and the orientation of each video screen 420 relative to the internal tissues and

organs of the patient PT5 are determined to enable the display on the video screens 420 of

images of selected target tissues of the patient. The reference markers facilitate the display on

screens 420 of respective views of the same organ or tissues from different angles depending on

the positions and orientations of the various screens 420.

As discussed above, for example, with reference to Figs. 20 and 21, computers or

processor 414 and 426 may include a module 362, typically realized as a programmed general

computer circuit, for highlighting a selected feature of the internal organs of patient PT4 or PT5.

The highlighting is achievable by modifying the color or intensity of the selected feature relative

to the other features in the displayed image, thus providing a visual contrast of the selected feature with respect to the other features of the displayed image. An intensity change may be

effectuated by essentially blacking or whiting out the other portions of the image so that the

selected feature is the only object displayed on the video screen.

The imaging devices of Figs. 24 and 26 are optionally provided with a voice-recognition

circuit 388 and a speech synthesis circuit 374 (Fig. 20) operatively connected to computer or

processor 414 and 426. Advantages and uses of these components are discussed above with

reference to Fig. 20. As further described above, computers or processors 414 and 426 are

possibly programmed for automated diagnosis based on pattern recognition, with the computed

diagnosis being communicated to the user physicians via speech synthesis circuit 374.

As illustrated in Fig. 28, the imaging device of Figs. 26 and 27 is advantageously

provided with a plurality of apertures or passageways 428 extending through bag 416 in the

interstitial spaces between video screens 420. Passageways 428 receive respective tubular

cannulas 430 which extend both through the passageways and respective openings (not shown) in

the skin and abdominal wall of the patient PT5. Medical instruments such as a laparoscopic

forceps 432 are inserted through passageways 428 for performing an operation on internal target

tissues of patient PT5 essentially under direct observation as afforded by video screens 420. The

distal ends of the medical instruments 432, inserted into patient PT5 in the field of view of the

imaging system, are displayed on one or more video screens 420 together with internal target

tissues of the patient. The uses of the imaging device of Figs. 25 and 26 with passageways 428

as illustrated in Fig. 28 are substantially identical to the uses and modes of operation described

above with reference to Figs. 20 and 21. It is to be noted that bag 416 may be replaced by a plurality of bags (not illustrated) all

filled with a fluidic medium through which ultrasonic pressure waves may be transmitted. Each

planar substrate or carrier pad 418 and its respective video screen may be attached to a respective

fluid-filled bag. In this modification of the ultrasonographic device of Figs. 25 and 26, apertures

performing the function of passageways 428 (Fig. 28) are naturally formed as gaps or spaces

between adjacent bags. Separate coupling elements (not illustrated) must be provided between

adjacent video screens 420 for forming an integral structure while enabling at least limited

flexing between adjacent video screens 420.

It is to be additionally understood that substrates 418 may be formed as carrier layers for

active picture elements of video screens 420 and may be visually indistinguishable from the

video screens 420.

The imaging devices of Figs. 24 and 25, 26 may include a transmitter 380 and a receiver

382 (Fig. 20) for operatively connecting scanners 410 and 422 and particularly computers or

processors 414 and 426 to a long-distance hard- wired or wireless telecommunications link. As

pointed out above, image data fransmitted over the telecommunications link to a video monitor at

a remote location will enable observation of the patient's internal tissues by distant specialists

who may also operate on the patients robotically via the telecommunications link.

Where the imaging device of Figs. 25-28 is used to diagnose or treat a limb or a joint,

planar substrates 418 and video screens 420 have sizes and two-dimensional shapes which

facilitate substantial conformity with the limb or joint. To facilitate the use of the imaging device

in invasive surgical procedures, the images provided on video screens 420 may be stereoscopic or holographic. Thus, manipulation of medical instrument 432 so that its distal end engages desired

internal tissues is facilitated. The imaging device thus may include elements for providing a

stereoscopic or holographic image to a viewer, the scanner including means for energizing the

elements to produce the stereoscopic or holographic image.

As illustrated in Fig. 29, another ultrasonic imaging system comprises a flexible substrate

or web 434 carrying a plurality of modular off-the-shelf transducer packages 436 disposed in a

substantially rectangular array. Each package 436 comprises a rigid substrate 437 to which is

mounted a multiplicity of piezoelectric crystal transducer elements 438. Transducer elements

438 are all electromechanical and may be termed "electroacoustic" in the case of excitation or

transmission of ultrasonic pulses and "acoustoelectric" in the case of reception or sensing of

reflected ultrasonic pulses. Transducer packages 436 may incoφorate an arrangement of one or

more off-the-shelf hardware components such as conventional ID and 1.5D arrays as described

elsewhere herein, or may be made up of an arrangement (e.g. a ID or 2D array) of scalar

transducer elements.

As discussed above, web 434 may be provided with or on a fluid-filled flexible bag (not

shown) for enhancing ultrasonic coupling with a curved surface such as a patient. Other,

measures may be utilized for facilitating ultrasonic pressure wave transmission from and to the

transducer elements 438 of the various modular transducer packages 436.

Generally, it is contemplated that the piezoelectric crystal elements 438 of any given

package 436 are energized simultaneously in excitation and reception to effectuate the scanning

of an acoustic beam used to interrogate the desired tissue. Thus, each transducer package 436 functions as a single data gathering aperture. The puφose of this technique is to enhance image

resolution over currently available ID and 1.5D array transducers, and to provide electronic 3D

volumetric data acquisition. Further enhancement is achieved by coherent aperture combining,

discussed below.

Piezoelectric crystal elements 438 are energized by ultrasonic electrical excitation

waveforms produced by a signal generator 440 in response to signals from an acquisition

controller 442. (Data transmission paths are indicated in Fig. 29 by solid line arrows, while

control signal links are indicated in dot-dash lines.) The excitation waveforms from signal

generator 440 are directed to selected packages or apertures 436 by a switching circuit or

multiplexer 444 in response to control signals from acquisition controller 442. The excitation

waveforms are of variable frequency, determined on a continuing basis by acquisition controller

442 and more particularly by a frequency determination module 476 thereof, for optimizing

image resolution at different depths (range) into the patient (for example, to obtain a uniform

resolution along all coordinate axes). Generally, the higher the frequency, the greater the depth

or penetration of effective data acquisition.

The excitation waveforms are generally transmitted as single pulses of short duration, or

bursts of several pulses sent and received one after the otherc. Any one pulse may be directed

to a single package or aperture 436 (single aperture excitation) or to multiple packages or

apertures 436 simultaneously (multiple aperture excitation). Similarly, signal reception may

occur using a single aperture at a given time, or using multiple apertures simultaneously.

Multiplexer 444 is connected to a receiver 446 and is responsive to acquisition controller 442 for selectively connecting the transducer elements 438 of packages or apertures 436 to the

signal generator and the receiver. Receiver 446 dynamically focuses incoming signals to

produce a number of vectors (range lines) of image data. To that end, receiver 446 incoφorates

demodulation circuits (not separately shown) to obtain coherently the received signals. It is to be

noted that multiplexer 444 may be disposed in whole or in part on web 434. Alternatively, the

multiplexer may be located at a workstation.

When different packages (or sets of packages) are used for transmission and reception, the

operating mode is termed "bistatic operation." When the same package (or set of packages) is

used for transmission and reception, the operating mode is termed "monostatic operation."

The coherent aperture combining module 488 can be used to increase the effective size of

the data gathering apertures employed, thereby increasing image resolution. CAC can be

performed using monostatic or bistatic operation. For bistatic operation, a given pulse is

fransmitted, for example, from one aperture, and received simultaneously from two (or more)

apertures. The transmit aperture could be one of the two (or more) apertures used for reception.

The receiver 446 processes the signals received from both apertures and produces two respective,

complex output images. For monostatic operation, two (or more) pulses are needed. On pulse

one, aperture one is used for fransmission and reception. On pulse two, aperture two is used for

fransmission and reception. In this case, the receiver 446 produces two respective complex

output images, but they pertain to two different times (i.e. the two times associated with the two

pulses). The monostatic operating mode has the disadvantage of possible phase shifts in

data received by the second transducer array or aperture, as compared with data received by the first transducer array or aperture, due to a different tissue scattering geometry, and different data

collection times.

The coherent aperture combining module 448 provides its coherently combined data to an image processor 450.

Image processor 450 utilizes the increased resolution data from module 448 (if CAC is

performed) to perform 3D image processing, which includes, as special cases, ID and 2D image

processing as well. 3D image processing can be used to construct three-dimensional models or

analogs of internal tissue structures of a patient during a real time scanning operation. As

discussed above with reference to other embodiments of an ultrasonic imaging system, an image

is constructed by image processor 450 pursuant to instructions entered by a user via a keyboard

452 or other input device and received by a command and confrol unit 454. The constructed

image is displayed on a monitor 456 by command and control unit 454.

During a diagnostic or treatment procedure utilizing the system of Fig. 29, a user requests

an image of a particular organ via input device or keyboard 452. Command and confrol unit 454

inteφrets the request and relays the inteφreted request to acquisition controller 442. Controller

422 queries image processor 450 to determine whether an image of the requested organ is already

stored in an internal memory (not shown) of the image processor. If the data is already obtained

or is obtainable via inteφolation, image processor 450 constructs the requested image, which is

then passed to monitor 456 via command and confrol unit 454. If the data required for imaging

the requested organ is not in memory, acquisition controller 442 determines which transducer

packages or apertures 436 must be excited and which transducer apertures 436 must be used for reception in order to obtain sufficiently high resolution data to form an image of the requested

organ structure. Pursuant to its determination, acquisition controller 442 activates signal

generator 440, multiplexer 444, and receiver 446 to implement the acquisition of the requisite

data. Prior to data collection, acquisition controller 442 accesses a calibration unit 458 to

determine whether a calibration sequence is needed. If so, acquisition controller 442 activates signal generator 440, multiplexer 444 and receiver 446 to conduct an ultrasonic scan for puφoses

of determining the locations and orientations of the various packages or apertures 436 relative to

each other.

Calibration is effectuated by one or both of two techniques. The first technique utilizes

acoustic point scatterers 460 (Fig. 30) such as AIUM phantoms disposed on packages or

apertures 436. Basically, transducer packages or apertures 436 are activated under the control of

acquisition controller 442 to obtain position data on the various point scatterers 460, while module 448 executes a self-cohering algorithm to determine the exact relative positions of the point scatterers, thereby determining the locations and orientations of substrates 437. It is contemplated that phantoms could be embedded in web 434 so that a sufficient number of point

scatterers are always in the image field of the group of apertures requiring registration. The calibration data may be acquired bistatieally (using a single pulse) or monostatically (using two or more pulses), as described above.

Fig. 31 is a diagram illustrating geometric parameters in the first calibration technique.

Two point scatterers or AIUM phantoms are located at points A and B. while fransducer arrays or apertures 462 and 464 are centered at points E and E. Transducer array or aperture 464 is rotated through an angle EAF and translated a distance AF-AE from the position of transducer 462. To

register transducer 464, it is necessary to determine angle EAF and distances AF and AE.

Distances FG, FH, GA, and HB are measured from data produced by transducer array or aperture

464, while distances ED, EC, DA, and CB are measured using data generated via transducer

array or aperture 462. Lengths b, £, and d are easily calculated next. Then, angle DAG is

computed. Subsequently, angles EAD and GAF and lengths AE and AF are determined. Angle

EAF equals angle EAD plus angle DAG plus angle GAF. ( EAF = EAD + DAG + GAF.) The

key to these computations is to recognize that the length of the vector joining two point scatterers

is invariant under coordinate system translations and rotations and hence will be measured the

same from both transducer array or apertures 462 and 464.

Assuming significant signal-to-noise ratios, the cross-range measurements are as good as

the apertures can provide, i.e., one picks the vector position where each point scatterer has

maximum intensity. Azimuthal cenfroiding can be used to further improve the cross-range

accuracy, depending on the size and orientation of the point scatterers relative to the cross-range

resolution of the arrays. To obtain suitable coherent aperture combining results, the range

measurements need to be accurate to the array focusing precision, which is better than 10

microns for premium systems. With sufficient signal-to-noise ratios, such accuracies can be

achieved by range over sampling (i.e., using the highest A D sampling rate available) combined

with range cenfroiding techniques. In addition, the point scatterers could also be fabricated in

pairs (or triplets, etc.) so that their separations are precisely known, which will assist in making

the resulting positioning information more accurate. Pursuant to the second calibration technique, a direct-path self-cohering algorithm is

used. A calibration or reference array or aperture receives a pulsed signal from two or more

arrays, whose positions and orientations are to be calibrated relative to each other. The reference

array is disposed generally on one side of a patient's body while the arrays to be calibrated are

disposed on another side of the body. In a given transverse plane through the patient and a

circumferentially extending array of fransducer apertures 436 , the locations of two points on

each array are needed to position and orient the array. (In a more general procedure, the

locations of three points on each fransducer must be determined.) Solving for the position of a

given point on a given array is a triangulation process using two half apertures of the reference

array. The two points (or phase centers) on each array correspond to two sub-apertures with a

high enough F# in azimuth and elevation to ensure that the calibration array is in the image field.

Let each sub-aperture transmit a pulse (or two pulses in sequence if array element access is not

available) and let the calibration array receive and process the pulse(s) in each of the two sub-

apertures. By measuring the range difference between the two, the position of the array point can

be computed relative to the reference array. It is to be noted that this description assumes that

the reference array and the arrays to be calibrated are nominally in the same elevation plane. The

process is repeated for all fransducer arrays or apertures 436 that are to be positioned relative to

each other. If all of the arrays in the plane are to be calibrated, then different arrays take turns

being the calibration array. Having multiple calibration arrays also allows estimates from

different calibration arrays to be averaged, perhaps making the process more robust to deviations from planarity. Accordingly, in the second calibration technique, the positions of a plurality of

preselected phase centres (associated with subapertures formed using a number of transducer

elements 438) are determined for each package or aperture 436 required to image the requested

organ structure, thereby specifying the location and orientation of those requisite packages or

apertures 436. The preselected phase centres are sequentially or separately energized with at

least one pulse of a predetermined frequency. At least one preselected transducer array, package

or aperture 436 is then polled or sampled using two half-apertures to sense incoming ultrasonic

pressure waves of the predetermined frequency transmitted directly (unreflected, although

perhaps refracted) through the internal tissues of the patient. Of course, bistatic operation and

access to individual fransducer elements in an array (i.e. to form the two half-apertures) are

required for this calibration procedure to work. The array element access requirement could be

eliminated by building reference arrays that consist of two elements joined rigidly (i.e., with

known, fixed separation).

The calibration procedure may be performed at regular intervals, with a periodicity

determined inter alia by such factors as the target region in the patient^-the purpose of the

imaging process, and the processing capacity of image processor 450. For example, image data

collection for a target region in or near the heart should be updated more frequently than image

data collection for a target region in a quiescent limb. Generally, therapeutic invasions require

continuous monitoring to a higher degree than diagnostic procedures.

It is to be noted that calibration may alternatively be effectuated by an auxiliary or

external sensing system different from transducer arrays or apertures 436. These alternative registration systems are not considered germane to the present invention and are not considered

herein.

Coherent aperture combining as implemented by module 448 is an application of

techniques known in the transmission and reception of wireless signals, including

electromagnetic radiation of various frequencies, as in the field of radar. Antenna array

principles are straightforwardly applied to a medical imaging system in order to improve the

spatial resolution provided by extant ultrasound array apertures. In general, the larger the

combined aperture, the better the lateral resolution.

The ulfrasonic imaging systems disclosed herein include appropriate hardware and

software (not illustrated) for signal amplification, analog-to-digital conversion, and focusing.

The advantageousness of these functions, as well as the elements required to perform these

functions, are well known in the conventional ultrasound arts and are not belabored herein.

Fig. 32 depicts transducer hardware which can be used in place of or as a component of

web 434 of Fig. 29. A multiplicity of off-the-shelf transducer packages or apertures 466 are

rigidly connected to each other in a rectangular array to form an ultrasonic sensor platen 468.

This platen or transducer carrier 468 can be used as a component in any of the systems described

above. More particularly, the platen can be used as a component in the construction of web 206

in Fig.12, web 216 in Fig. 13, sensor web 232 in Figs. 14-15, plate 304 in Figs. 16-17, panels

320, 322 and 324 in Figs.18-19, cover sheet 332 in Fig.19, web 350 in Fig.20, blanket 358 in

Fig.21, blanket 396 in Fig. 22N cuff 400 in Fig. 23 A and Fig. 23B, subsfrate 404 in Fig. 24 and

substrates 418 in Figs. 25-26. Pursuant to some of those systems, platen or transducer carrier 468 is provided with a fluid-filled flexible bag ( e.g. 306 in Fig. 18; 316 in Figs. 18 and 19)

disposable in contact with the patient for facilitating transmission of pressure waves into the

patient from transducer packages or apertures 466 and transmission of reflected pressure waves from the patient to receiving transducer packages or apertures 466.

The transducer packages 466 (in platen 468) use 1.5D transducer array technology

found in conventional, premium probes. This technology employs piezoelectric crystal elements

(not shown) whose size along the length dimension is one-wavelength or less, whereas, the size

along the width dimension is typically several wavelengths. Each transducer package 466

contains on the order of 100 elements, tightly packed, along the length (or azimuth) dimension, and only a few (usually less than 10) elements, also tightly packed, along the width (or elevation)

dimension. Due to the fine spacing along the length dimension, each transducer package can be electronically scanned in azimuth; however, in a conventional probe, no scanning is performed in elevation. A unique feature of the present invention is the ability of platen 468 to scan in elevation as well as azimuth using conventional transducer element technology as described above. While full 2D electronic scanning is well understood if the transducer elements are one- wavelength or less in both the length and width dimensions (and in which case many, many more

elements will be needed to tightly pack a specified-size, 2D platen, and similarly, many more receiver channels will also be required, adding dramatically to the cost and practicality of such a

platen), 2D scanning using transducer elements whose feature size is large in the width dimension (as is used herein) is not understood and a unique approach is described below in support of the present invention. As described above, electronic scanning (using phased-array signal processing circuitry) is confined to a data gathering aperture. Platen 468 can be organized

into one or more data gathering apertures where each data gathering aperture is capable of 2D

scanning; and hence, provides electronic 3D volumetric data acquisition of the tissue structures in

the imaging field (i.e. below the skin surface in acoustic contact with the aperture). The

acquisition controller 442 (Fig. 29) is provided with phased-array signal processing circuitry 470

for effectuating the 2D electronic scanning of the internal tissue structures associated with each

data gathering aperture.

As illustrated in Fig. 33, phased-array signal processing circuitry 470 includes a TX

timing module 472 operatively connected to multiplexer or switching circuit 444 for calculating

a set of time delays or phases of electrical signals to be sent to the different transducer packages

or apertures 466 to effectuate a 2D electronic scan of internal tissue structures of a patient by

outgoing pressure waves (i.e. on transmission). The multiplexer or switching circuit 444 imparts

the time delays or phases so computed. Thus, the variations in the time delays or phases of

electrical signals sent to the different transducer packages or apertures 466 is effectuated in part

by multiplexer or switching circuitry 444 under the control of acquisition controller 442 and

more particularly in response to control signals from module 472 of phased-array signal

processing circuitry 470.

As further illustrated in Fig. 33, phased-array signal processing circuitry 470 further

includes an RX timing module 474 operatively connected to multiplexer 444 and receiver 446

and which computes time delays or phases to be used to for effectuating a 2D electronic

scanning of incoming reflected pressure waves by transducer packages or apertures 466. The application of the computed time delays or phases to the received signals is typically performed

in the receiver 446 although it could be distributed between the multiplexer 444 and the receiver

446.

The phased-array signal processing circuitry 470 performs azimuth (i.e. in the length dimension) electronic scanning in a conventional-like manner. If a data gathering aperture

employs a single, off-the-shelf, transducer array, then azimuth scanning (using sequential scanning techniques for a linear array or phased-array scanning for a phased-array) is performed

conventionally. If two or more transducer arrays make up the length dimension of the data

gathering aperture to form a larger effective aperture, then a straightforward extension of

conventional azimuth scanning is applied so that the signals received from each fransducer array

can be coherently added (in the multiplexer 444 or receiver 446) to effect scanning from the larger effective aperture. If scalar transducer elements are employed in the platen 468 rather than

fransducer arrays, again, a straightforward application of conventional scanning techniques can

be applied to effectuate azimuth scanning because the locations of all scalar elements are known. The phased-array signal processing circuitry 470 performs elevation (i.e. in the width dimension) electronic scanning in a non-conventional manner , although conventional principles are applied in terms of the beam focussing techniques used to focus a given voxel (i.e. the image location in the 3D volumetric region being interrogated). This elevation scanning will now be described using as an example the case where the fransducer packages 466 used in platen 468 are 1.5D array substrates, each containing on the order of 100 elements in the length dimension, and

say seven elements in the width. In practice, elevation scanning is not performed with probes containing 1.5D arrays. A typical probe may have a width dimension of say 1 cm and a length

dimension of say 4 cm. When the probe is at a given location, an image slice can be acquired

which is typically about 1 mm thick in the elevation or width dimension, and 4 cm long in the

azimuth or length dimension. The length of the slice in the depth dimension, D cm, relates to the

depth interval in the tissue that is being interrogated. The 1 mm thick image slice is moved

manually by the operator's hand in the elevation dimension. That is, the operator manipulates

the probe by moving it in the elevation dimension, which in turn moves the image slice in a

continuous fashion in the elevation dimension. Consider now the case where platen 468 contains

four 1 cm by 4 cm array subsfrates stacked in the width dimension so that the platen dimension is

4 cm by 4 cm, and assume that a single data gathering aperture is formed from the four substrates

contained within the platen. If conventional scanning techniques are applied independently to

each substrate, then four 1mm by 4cm by D cm image slices can be obtained. Although these

slices do indeed span a volume (i.e. one could argue that electronic 3D data acquisition is

provided), the volume is not useful in practice because there are large gaps (i.e. 9mm in width) of

volumetric data that are missing between adjacent subsfrates. Whereas the total spanned volume

is 4cm x 4cm by D cm, only 10% of that volume can be electronically acquired. Although

individual substrates cannot electronically scan a full set of scanning angles in the elevation

dimension due to the large size of the width dimension of the scalar transducer elements (i.e.

several wavelengths), a small amount of electronic scanning, as much as +/- 10 deg., is

achievable (although not needed nor used in practice with 1.5D probes) without suffering grating

lobes or reduction in gain due to the directivity of the scalar element pattern response. This elevation scanning capability is exploited by phased-array signal processing circuitry 470 to fill

in the gaps in coverage that would otherwise result, thereby truly providing electronic 3D

volumetric data acquisition.

Pursuant to the example in the preceding paragraph, phased-array signal processing

circuitry 470 is programmed to provide full, electronic 3D volumetric data acquisition. Any

given transducer substrate can be scanned upwards or downwards exemplarily 0.1 radians in the

elevation dimension by applying appropriately computed time delays to the seven elements in the

width dimension. It will now be explained how this phased array scanning accommodates or

compensates for the 9 mm gap in the width dimension contained between two adjacent

substrates. At a depth of 5 cm, the beam scanned upwards from the lower subsfrate will intersect

the beam scanned downwards by the upper substrate, thereby providing full coverage (i.e.

completely filling in the gap) for depths greater than five centimetres. The same coordinated

approach is used between other adjacent substrates to acquire the complete 3D volume for

depths greater than 5 cm. Gaps for nearer-in depths are filled by treating the collection of scalar

elements contained in the width dimension of the data gathering aperture (at a given location

along the length of the data gathering aperture) as a single array, and using appropriate sub-

apertures depending on the width interval being interrogated. One can appreciate that by

designing a subaperture so that its phase centre is sufficiently close to the gap in question will

insure that the gap can be filled in (i.e. interrogated by the subaperture). The subaperture

approach also has the advantage that an instantaneous aperture larger than the width dimension (1

cm in this example) of each substrate can be used to increase the elevation resolution, which is

MISSING AT THE TIME OF PUBLICATION

hereinafter) is needed to reduce the acquisition time. The situation is compounded further when

3D volumetric data acquisition is performed. If a full 2D array containing 100 elements closely

spaced in each of the length and width dimensions is used, then about 33 pulses (with the factor

of 3 multiplexing accounted for) are needed for elevation scanning, for each azimuth beam. As a

result, the acquisition time increases proportionately to approximately 220 ms. If multiple pulses

are needed for each vector for multiple depths of focus, the acquisition time further increases

proportionately. For platen 468 utilizing 1.5D array subsfrates, on the order of 10 elevation

beams (i.e., pulses assuming 1 pulse per beam) are needed to fill the 1 cm gap (each slice is about

1 mm thick in the elevation dimension) between adjacent array substrates. Assuming that the

adjacent 1.5D array substrates are operated simultaneously (or near simultaneously), then 330

pulses are needed for 3D volumetric scanning, requiring an acquisition time of 66 ms. Again,

multiple depths of focus will multiply this acquisition time.

The discussion in the preceding paragraph illustrates the need to reduce acquisition time

for full 2D scanning arrays, and for platen 468 of the above example, utilizing 1.5D array

substrates, in certain applications. Conventional azimuth electronic scanning (and by extension,

elevation scanning) transmits pulses sequentially; that is, the first pulse is fransmitted (i.e. first

pressure wave) and received (i.e. second pressure wave) prior to transmitting the next pulse. In

order to reduce the total acquisition time for 3D volumetric data acquisition (which includes 2D

acquisition as a special case as described earlier), several pulses are to be fransmitted in rapid

succession (i.e., one following immediately after the preceding pulse is launched) so that several

pulses are in-flight simultaneously. Each of the in-flight pulses is transmitted with a different transmit beam separated significantly (i.e., in azimuth and/or elevation) from the other transmit

beams associated with the other in-flight pulses. This beam-pulse interleaving technique reduces

(to acceptable levels) the co-beam-pulse interference caused by the other in-flight pulse returns

when forming the receive beams (i.e., vectors) associated with a given in-flight pulse's returns.

Furthermore, the beam-pulse interleaving technique causes the acquisition time to be reduced by

a factor equal to the average number of in-flight-pulses. The selection of beam-pulse sets for use

with this beam-pulse interleaving technique need not be regular, and can be optimized both in

terms of the number of beams per set and their locations (in azimuth, elevation or both) so as to

meet the acquisition time requirements while maintaining specifications on co-beam-pulse

interference rejection. The costs associated with employing the beam-pulse interleaving

technique are an increased minimum depth (range) of operation which corresponds to the total

time taken to transmit the in-flight pulses in rapid succession (which is small in practice), and

increased computational requirements to form the multiple receive beams (vectors) in parallel, in

order to maintain real-time performance.

A variation to the beam pulse interleaving technique described above would cause

successive in-flight pulses to be launched each using a different waveform code (i.e., waveform

pulse interleaving) which varies any or all of the amplitude, frequency or phase of the transmitted

pulse rather than (or in addition to) directing each pulse to different spatial directions or beams.

In this way, the co-waveform pulse interference can be reduced to acceptable levels, thereby

separating the interfering returns from different in-flight pulses. Such approaches are likely to be

more suitable for narrow band systems than for wide band systems. An alternative to the rapid, successive transmission of in-flight pulses each directed using

a different transmit beam is to form a composite transmit beam pattern representing the

supeφosition of the individual beam patterns associated with the in- flight pulses, and

transmitting a single pulse. This alternative approach, however, can suffer from reduced power

directed to the associated beam directions, and hence reduced power on receive.

It is emphasized here that the aforementioned beam-pulse interleaving technique is

applicable to both full 2D scanning arrays as well as those based on 1.5D technology as

described in the instant disclosure. The scanning functionality provided by the beam-pulse

interleaving technique forms part of the phased-array signal processing circuitry 470.

Phased-array signal processing circuitry 470, like acquisition controller 442 as a whole

and other components shown in Fig. 29, is realizable in the form of digital processor circuits

modified by programming to operate transducer packages or apertures 466 as a phased array.

Thus, phased-array signal processing circuitry 470 and the signal processing and control

elements of Fig. 29 are all realizable by a properly programmed digital computer. It should be

noted that the terminology "phased array" used throughout this application is intended to be

applicable to both narrow-band and wide-band waveforms, although, strictly speaking, the term

originates from systems employing narrow-band waveforms where the phase of a signal is varied

to effectuate scanning. It is understood that for wide-band waveforms such as those often

employed in ultrasound systems, it is the time delay of the signals (rather than the phase) that

must be varied across a given data gathering aperture in order to effectuate electronic scanning.

In the instant disclosure, the term "delay" is intended to cover both a phase variation and a time delay as applicable in the use of wide-band waveforms.

It is of interest that imaging occurs in the far field of each individual transducer element

438 and in the near field of package or array aperture 436. The near-field variation of a

wavefront across an aperture 438 is quadratic. As a result, focusing an array aperture in a

phased-array process is achieved by computing and applying the appropriate quadratic time

delays, for the location in question that is being focused. A variety of approaches are known to

those skilled in the art to optimize this process for a given application.

Of course, the physics of ultrasound are well documented and understood. Software for

any of the ultrasonic imaging systems herein entails a straightforward application of the

appropriate wave equations. See , for instance, Principles of Aperture and Array System Design,

B.D. Steinberg, John Wiley, 1976, and Ultrasonic Imaging Using Arrays, Proc. IEEE, Vol. 67,

No. 4, April 1979, pp 484-495.

Although the invention has been described in terms of particular embodiments and

applications, one of ordinary skill in the art, in light of this teaching, can generate additional

embodiments and modifications without departing from the spirit of or exceeding the scope of

the claimed invention. It is to be understood, for instance, that the various processing functions

(e.g., aperture formation, coherent aperture combining, self-cohering algorithm calculation, etc.)

may be performed by a specially programmed general puφose computer as disclosed herein or,

alternatively, by hard wired circuits. Hard wiring may be especially advantageous for various

preprocessing and calibration or position determination computations.

Moreover, it is to be noted that multiple images may be provided on a single video screen, pursuant to conventional windows-type overlay techniques. Thus, one window or video

image may show an organ from one point of view or angle, while another window on the same

screen may show the same organ from a different vantage point. Alternatively, one window may

show a first organ, while another window displays one or more organs underlying the first organ.

In this case, the underlying organs may be shown in phantom line in the first window, while the

overlying organs is shown in phantom lines in the second window. Of course, all such operating

modes apply to multiple video screens as well as to a single screen. Thus, one screen may

display an overlying organ from one angle, while an adjacent organ displays an underlying organ

from a different angle. A display window on a video screen of the present invention may be used

alternatively for the display of textual information pertaining to the tissues and organs displayed

in other video windows. Such information may include diagnostic information determined by

the analyzing computer.

It is to be further noted that the 1.5D transducer arrays discussed herein could be replaced

by so-called 1.75D arrays. Accordingly, the term "1.5D transducer array" as used herein should

be understood to encompass 1.75D fransducer arrays, as well.

Accordingly, it is to be understood that the drawings and descriptions herein are profered

by way of example to facilitate comprehension of the invention and should not be construed to

limit the scope thereof.

Claims

WHAT IS CLAIMED IS:

1. A medical system comprising:

a carrier;

a multiplicity of electromechanical transducers mounted to said carrier, said transducers

being disposable in effective pressure-wave-fransmitting contact with a patient;

energization means operatively connected to a first plurality of said transducers

forsupplying same with electrical signals of at least one pre-established ultrasonic frequency to

produce first pressure waves in the patient; and

a control unit operatively connected to said energization means, said control unit

including an electronic analyzer operatively connected to a second plurality of said fransducers

for performing elecfronic 3D volumetric data acquisition and imaging of internal tissue structures

of the patient by analyzing signals generated by said second plurality of said fransducers in

response to second pressure waves produced at said internal tissue structures in response to said

first pressure waves, said control unit including phased-array signal processing circuitry for

effectuating an elecfronic scanning of the internal tissue structures to facilitate electronic 3D

volumetric data acquisition.

2. The system defined in claim 1 wherein said carrier is rigid.

3. The system defined in claim 2 wherein said carrier comprises a plurality of rigid modular substrates rigidly connected to one another, each of said subsfrates holding a plurality of

said transducers.

4. The system defined in claim 2 wherein said carrier is provided with a fluid-filled

flexible bag disposable in contact with the patient for facilitating transmission of said first

pressure waves into the patient from said first plurality of said transducers and reception of said

second pressure waves by said second plurality of said transducers.

5. The system defined in claim 1 wherein said phased-array signal processing circuitry

include means operatively connected to said energization means for independently varying a time

delay of said electrical signals across said first plurality of transducers to effectuate an electronic

scanning of said internal tissue structures of the patient by said first pressure waves.

6. The system defined in claim 5 wherein said means for varying includes switching

circuitry operatively connected to said first plurality of said fransducers.

7. The system defined in claim 1 wherein said phased-array signal processing circuitry

includes switching circuitry for varying sampling times of said second pressure waves by said

second plurality of said transducers and further including combining circuitry for combining the

sampled signals to effectuate an elecfronic scanning of said second pressure waves by said second

plurality of transducers.

8. The system defined in claim 7 wherein said means for varying includes switching

circuitry.

9. The system defined in claim 1 wherein said second plurality of said transducers

includes transducers different from the transducers in said first plurality of said transducers.

10. The system defined in claim 1 wherein said confrol unit includes circuitry operatively

connected to said energization means for varying said frequency to facilitate collection of three-

dimensional structural data pertaining to tissue structures at different depths in the patient.

11. The system defined in claim 1 wherein said carrier is provided with at least one

chamber for holding a fluid, said transducers being in pressure-wave communication with said

chamber, thereby facilitating pressure wave transmission from said first plurality of said

fransducers to the patient and from the patient to said second plurality of said fransducers.

12. The system defined in claim 1, further comprising at least one display operatively

connected to said analyzer for providing an image of said internal tissue structures of the patient.

13. A medical method comprising:

providing a carrier holding a multiplicity of electromechanical transducers; placing said carrier and a patient adjacent to one another so that said fransducers are

disposed in effective pressure-wave-transmitting contact with the patient;

supplying a first plurality of said transducers with electrical signals of at least one

pre-established ultrasonic frequency to produce first pressure waves in the patient;

receiving, via a second plurality of said transducers, second pressure waves produced at

internal tissue structures of the patient in response to said first pressure waves; and

performing electronic 3D volumetric data acquisition and imaging of said internal tissue

structures by analyzing signals generated by said second plurality of said fransducers in response

to said second pressure waves,

at least one of the supplying and receiving steps being executed to effectuate an electronic

scanning of said internal tissue structures.

14. The method defined in claim 13 wherein the elecfronic scanning is accomplished by

varying a time delay of said electrical signals across said first plurality of said fransducers to

effectuate a phased-array electronic scanning of internal tissues of the patient by said first

pressure waves.

15. The method defined in claim 14 wherein the varying of the time delay of said

electrical signals includes operating switching circuitry operatively connected to said first

plurality of said transducers.

16. The method defined in claim 13 wherein the electronic scanning is accomplished by

varying sampling time or phase of said second plurality of said transducers.

17. The method defined in claim 16 wherein the varying of the sampling time or phase of

said electrical signals includes operating switching circuitry operatively connected to said second

plurality of said fransducers.

18. The method defined in claim 13 wherein said carrier is rigid, further comprising

disposing a flexible fluid-filled bag between the patient and said carrier and fransmitting said first

pressure waves and receiving said second pressure waves through said fluid filled flexible bag

19. The method defined in claim 13, further comprising varying said frequency to

depths in the patient;

20. The method defined in claim 13, further comprising generating an image of the

internal tissues of the patient on at least one display.

21. The method defined in claim 13, further comprising maintaining said fransducers in

substantially fixed positions relative to one another during:

the supplying of said first plurality of said transducers with said electrical signals;

the receiving, via said second plurality of said fransducers, of said second pressure waves; and

the performing of said 3D volumetric data acquisition and imaging of said internal tissue

structures.

22. A medical system comprising:

a carrier;

a multiplicity of electromechanical transducers mounted to said carrier;

energization means operatively connected to a first plurality of said transducers for

supplying same with electrical signals of at least one pre-established ulfrasonic frequency to

produce first pressure waves in the patient; and

a control unit operatively connected to said energization means for operating same to

produce said first pressure waves in the patient, said control unit including an electronic analyzer

operatively connected to a second plurality of said transducers for performing electronic 3D

volumetric data acquisition and imaging of internal tissues of the patient by analyzing signals

generated by said second plurality of said transducers in response to second pressure waves

produced at internal tissues of the patient in response to said first pressure waves, said confrol

unit being operatively connected to said second plurality of said transducers to gather and

organize data from said second plurality of said fransducers so that said second plurality of

fransducers define a plurality of data gathering apertures, said control unit including circuitry for

coherent aperture combining to coherently combine structural data from the respective apertures.

23. The system defined in claim 22 wherein said carrier includes a plurality of rigid

substrates each disposable in pressure-wave transmitting contact with the patient, each of said

substrates carrying a respective plurality of said transducers, each of said substrates carrying at

least one of said second plurality of said transducers so that each of said substrates represents a

respective one of said data gathering apertures.

24. The system defined in claim 23 wherein said substrates are movably connected to one

another, said circuitry including position determination or calibration means for determining

relative positions and orientations of said substrates relative to one another.

25. The system defined in claim 24 wherein said position determination or calibration

means includes a multiplicity of point scatterers, said position determination or calibration means

further including programmed componentry operatively connected to said energization means for

periodically scanning said point scatterers with first ulfrasonic pressure waves and calculating

instantaneous positions of said point scatterers as scanned by each of said subsfrates using second

ulfrasonic pressure waves produced at said point scatterers in response to said first ulfrasonic

pressure waves.

26. The system defined in claim 25 wherein said elecfronic analyzer includes circuit

components for sampling data from said second plurality of said transducers so that at least some

of said transducers form a plurality of data gathering apertures, said confrol unit including coherent aperture combining circuitry for coherently combining structural data from the

respective apertures, said position determination or calibration means including circuitry for

executing a self-cohering algorithm (a)computing relative positions and orientations of said

substrates using instantaneous position measurements and (b) adjusting signals from coherently

combined apertures to enable constructive addition of said signals from said coherently combined

apertures.

27. The system defined in claim 25 wherein said position determination or calibration

means includes means for executing computations according to a self-cohering algorithm.

28. The system defined in claim 24 wherein said position determination or calibration

means includes programmed componentry operatively connected to said energization means for

periodically energizing at some of said fransducers with at least one predetermined electrical

frequency and calculating instantaneous positions of the transducers so energized.

29. The system defined in claim 23, further comprising at least one display operatively

30. The system defined in claim 23 wherein said substrates are connected to one another

via a flexible linkage so that said substrates are extendable at a variable angle with respect to one another.

31. A medical method comprising:

providing a carrier holding a multiplicity of electromechanical transducers defining

respective data gathering apertures; placing said carrier and a patient adjacent to one another so that said transducers are

disposed in effective pressure-wave-transmitting contact with the patient;

supplying a first plurality of said fransducers with electrical signals of at least one

receiving, via a second plurality of said fransducers, second pressure waves produced at

internal tissue structures of the patient in response to said first pressure waves; and performing electronic 3D volumetric data acquisition and imaging of said internal tissue

to said second pressure waves,

at least one of the steps of supplying and receiving including coherently combining structural data from the respective apertures.

32. The method defined in claim 31 wherein said carrier includes a plurality of rigid substrates and wherein the step of coherently combining includes determining relative positions

and orientations of said substrates relative to one another.

33. The method defined in claim 32 wherein each of said substrates is provided with a

plurality of point scatterers, the determining of relative positions and orientations of said

substrates including periodically scanning said point scatterers with ultrasonic pressure waves

and calculating instantaneous positions of said point scatterers.

34. The method defined in claim 33 wherein the determining of relative positions and

orientations of said carriers includes executing computations according to a self-cohering

algorithm.

35. The method defined in claim 32 wherein the determining of relative positions and

orientations of said carriers includes periodically energizing at some of said transducers with at

least one predetermined electrical frequency and calculating instantaneous positions of the

fransducers so energized.

36. The method defined in claim 35 wherein the determining of relative positions and

algorithm.

37. A medical scanning apparatus comprising:

a plurality of 1.5D transducer arrays rigidly connected to one another; and

phased-array signal processing circuitry operatively connected to said 1.5D fransducer arrays, said phased-array signal processing circuitry for operating said transducer arrays and

processing signals therefrom in a coherent aperture combining mode to effectuate an electronic

3D volumetric scan of a patient's internal tissues.

38. The apparatus defined in claim 37 wherein said phased-array signal processing

circuitry includes means for effectuating a 2D scan in elevation and azimuth directions of said

transducer arrays

39. A medical method comprising: disposing a multiplicity of electromechanical fransducers in a predetermined array in

effective pressure-wave-transmitting contact with a patient;

after the disposing of said transducers in contact with the patient, selectively energizing a

first plurality of said transducers to transmit a plurality of ulfrasonic pulses into the patient, said

pulses inducing a generation of reflected pressure waves at internal tissue structures in the patient,

said pulses being transmitted into the patient prior to a return to said fransducers of a substantial

amount of the reflected pressure waves, said pulses being differentially coded to enable detection

of respective series of reflected pressure waves;

receiving, via a second plurality of said fransducers, the reflected pressure waves

produced at the internal tissue structures of the patient in response to said pulses;

decoding the reflected pressure waves to associate the reflected pressure waves with

respective ones of said pulses; and performing electronic 3D volumetric data acquisition and imaging of said internal tissue

structures in part by analyzing the decoded received reflected pressure waves.

40. The method defined in claim 39 wherein the differential coding of said pulses is a

spatial coding.

41. The method defined in claim 40 wherein said pulses are transmitted in respective

different directions into the patient.

40. The method defined in claim 39 wherein said transducers are mounted to a flexible

web, the disposing of said transducers in a predetermined array in effective pressure-wave- transmitting contact with a patient including placing said web in contact with the patient.