US 20100312094 A1
The systems include a display with a User Interface in communication with a circuit, the display is configured to display a patient model/map or model of target anatomical structure. The User Interface is configured to allow a user to select at least one target site (e.g., ablation site) on the model/map whereby scan planes for a corresponding location in 3-D space for the selected target ablation site are pre-set for future use. The circuit can be configured to automatically direct the MRI Scanner to use the pre-set scan planes to obtain MR image data when an intrabody device such as an ablation catheter is at the location that corresponds with the selected target site.
1. An MRI guided system, comprising:
a circuit; and
a display in communication with the circuit, the display having a User Interface (UI), the display configured to display a volumetric planning model of a target anatomical structure of a patient, wherein the UI is configured to allow a user to select at least one target site on the planning model, and wherein the circuit associates at least one pre-set scan plane for the at least one selected target site for subsequent use.
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23. An MRI guided system, comprising:
a circuit integrated into and/or communicating with a clinician workstation, the workstation comprising a display with a User Interface, the display configured to display at least one patient volumetric model of target anatomy, wherein the User Interface is configured to allow a user to select target sites on the at least one displayed model, wherein the circuit electronically associates pre-set scan planes for an MRI Scanner for the selected target sites for future use.
24. The system of
25. A method for carrying out an MRI-guided procedure, comprising:
displaying a volumetric model of a target patient anatomical structure;
electronically identifying at least one target site on the displayed model;
registering the model to 3-D MRI imaging space after the identifying step and before or during introducing an intrabody device into the patient during an MRI guided procedure;
electronically associating at least one pre-set MRI image scan plane for a respective identified target site after the registering step;
guiding the intrabody device with at least one tracking coil to a target intrabody location using near real time MR image data and tracking coil signal data generated by the at least one tracking coil;
automatically electronically using the at least one pre-set scan plane associated with one of the at least one identified target sites to obtain near real time MR image data when a distal end portion of the intrabody device is determined to be proximate a corresponding location in the body based on the tracking coil signal data;
treating and/or evaluating target tissue using the intrabody device; and
displaying near real-time MR images of the target tissue during the guiding, treating and/or evaluating steps using the obtained MR image data.
26. The method of
27. The method of
28. The method of
displaying a post-treatment model of the patient's anatomical heart structure;
accepting user input to select target sites on the post-treatment model to select at least one additional treatment site for clean-up to facilitate desired therapeutic coverage or a complete lesion pattern formation for electrical isolation;
electronically defining a pre-set scan plane for the selected at least one additional treatment site;
automatically electronically using the at least one pre-set scan plane associated with the additional target treatment site when a distal end portion of the intrabody device is determined to be proximate a corresponding location in the heart to obtain near real time MR image data;
treating the additional treatment site; and
displaying near real-time MR images of the target tissue during the treating step using the obtained MR image data.
29. A computer program product for facilitating an MRI-guided procedure of a patient, the computer program product comprising:
a non-transitory computer readable storage medium having computer readable program code embodied in the medium, the computer-readable program code comprising:
computer readable program code that defines at least one pre-set scan plane for a respective target site based on a user's marking and/or selection of a least one target site on a model of a patient's target anatomical structure via a User Interface.
30. The computer program product of
31. The computer program product of
32. The computer program product of
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34. The computer program product of
35. An MRI cardiac interventional system, comprising:
a processor in communication with the display;
electronic memory coupled to the processor; and
computer program code residing in the memory that is executable by the processor for:
displaying a graphical user interface (GUI) containing at least one anatomical model of at least a portion of the heart within the display, wherein the GUI allows a user to select target sites on the model; and
defining associated pre-set scan planes for the selected target sites.
This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/185,072 filed Jun. 8, 2009, U.S. Provisional Application Ser. No. 61/187,323 filed Jun. 16, 2009, U.S. Provisional Application Ser. No. 61/219,638 filed Jun. 23, 2009, and U.S. Provisional Application Ser. No. 61/261,103 filed Nov. 13, 2009, the contents of which are hereby incorporated by reference as if recited in full herein.
The present invention relates to MRI-guided systems and may be particularly suitable for cardiac systems, such as cardiac EP systems for treating Atrial Fibrillation (AFIB).
Conventional Cardiac EP (ElectroPhysiology) Systems are X-ray based systems which use electroanatomical maps. Electroanatomical maps are virtual representations of the heart showing sensed electrical activity. Examples of such systems include the Carto® electroanatomic mapping system from Biosense Webster, Inc., Diamond Bar, Calif., and the EnSite NavX® system from Endocardial Solutions Inc., St. Paul, Minn.
However, there remains a need for MRI-guided systems that can use MRI to obtain details of tissue not provided by X-ray based systems and/or to reduce patient exposure to radiation associated with interventional (diagnostic and/or therapeutic) procedures.
Some embodiments are directed to MRI guided systems that include a circuit and a display in communication with the circuit, the display having a User Interface (UI). The display is configured to display a volumetric planning model (also referred to interchangeably as a map) of a target anatomical structure of a patient. The UI is configured to allow a user to select at least one target site on the planning model and the circuit defines at least one pre-set scan plane for the at least one selected target site for subsequent use. The target site can be a target treatment site or diagnostic site or a site of interest such as a site used to form an intrabody path (e.g., septal puncture).
The circuit can be in communication with (or adapted to communicate with) an MR Scanner having a 3-D imaging space with a coordinate system. The circuit can be configured to electronically register the planning model or image to the 3-D MRI imaging space with the at least one selected target site so that the at least one pre-set scan plane is electronically adjusted based on the registered planning model or image.
The circuit can be configured to allow a user to select one of a plurality of different pre-defined surgical procedure options, each having an associated set of different proposed treatment sites that in response to user selection can be electronically automatically placed on the planning model.
The circuit can be configured to provide an adjustable template or grid that is electronically applied to the planning model and provides suggested treatment sites.
The circuit can be configured to automatically electronically direct an MRI Scanner to use the at least one pre-set scan plane associated with a corresponding selected target site to obtain MR image data when a distal end portion of an intrabody device is determined to be proximate a location that corresponds to the selected target treatment site.
The planning model can be an interactive model. The UI can be configured to allow a user to rotate the planning model and electronically mark target sites to select the target sites at different locations.
The circuit can be configured to present suggested scan planes that will generate at least one image slice that will include relevant local tissue associated with the at least one selected target site based on a contour of the tissue.
In some embodiments, in response to the user selection of the at least one target site on the planning model, the circuit can also electronically associate a corresponding 3-D perspective viewing window of the model that is subsequently automatically displayed during an MRI guided procedure when an intrabody device is at the location in the body that corresponds to the selected target site.
The display can include a viewing window with near real-time MR images of local tissue being actively treated by an intrabody device. The circuit can generate the near real-time MR images using at least one pre-set scan plane associated with a target site having a location that is proximate a calculated location of a distal end portion of the intrabody device.
In some embodiments, the system can include at least one intrabody device with at least one tracking coil connected to a channel of an MR Scanner. The circuit can include dimensional and/or configuration data about the device. The circuit can direct the MR Scanner to obtain an image slice of relevant local tissue using the at least one preset scan plane associated with a target site having a location that is proximate a calculated location of a distal end portion of the intrabody device. The image slice can include tissue at a location that is adjacent the interface of the device and tissue and may include tissue a defined distance beyond the intrabody device.
In some embodiments, the at least one target site is a plurality of target treatment sites, each having a corresponding at least one pre-set scan plane.
The selectable procedures, where used, may optionally include different cardiac arrhythmia procedures. The circuit can electronically apply a suggested (e.g., contiguous and/or linear) ablation pattern to the planning model that can be electronically adjusted by a user.
The grid or template, where used, may have an adjustable suggested (e.g., contiguous and/or linear) ablation pattern for forming transmural lesions that can be electronically applied to the planning model.
The circuit may be configured to electronically apply a suggested grid or template that is automatically adjusted to fit patient contour based on predefined anatomical features electronically located in or on the planning model.
The system can be a cardiac EP system. The system can include an ablation catheter with a plurality of spaced apart tracking coils on a distal end portion thereof. The at least one selected target treatment site can include a plurality of spaced apart target ablation treatment sites associated with different associated pre-set scan planes. The circuit can be configured to track location of the ablation catheter in the heart in 3-D MRI image space and render a physical representation of the ablation catheter in a visualization shown on the display. The circuit can be configured to render the visualization to show the ablation catheter location with respect to a rendered patient volumetric model of the heart.
The circuit can be configured to show near real time MRI image data during ablation on the display using the at least one pre-set scan plane for a respective selected target treatment ablation site.
The patient volumetric model in the visualization can comprise a tissue characterization model and/or an electroanatomical model.
The circuit can be configured to generate suggested scan planes and show them on the display with respect to the planning model and at least one target treatment site.
The circuit can be configured to provide the planning model without the planning model registered to 3-D MRI image space. The circuit can be configured to associate the pre-set scan planes with the planning model then register the planning model with the associated pre-set scan planes to 3-D MRI image space at a subsequent time.
The circuit can automatically identify spatial coordinates of the pre-set scan planes based on the registered planning model.
Yet other embodiments are directed to MRI guided cardiac systems. The systems include a clinician workstation in communication with a circuit or having a circuit. The workstation includes a display with a User Interface. The display is configured to display at least one patient volumetric model of the heart. The User Interface is configured to allow a user to select target ablation sites on the displayed model. The circuit electronically associates pre-set scan planes for the selected target ablation sites for future use.
The circuit can be configured to register the model of the heart to 3-D imaging space associated with an MR Scanner and automatically electronically direct the MRI Scanner to use at least one of the pre-set scan planes to obtain near real time MR image data when an ablation catheter is proximate a location in the heart corresponding to the selected target ablation site associated with the at least one scan plane during an ablation using the ablation catheter.
Still other embodiments are directed to methods for carrying out an MRI-guided procedure. The methods include: (a) displaying a volumetric model of a target patient anatomical structure; (b) electronically identifying at least one target site on the displayed model; (c) electronically associating at least one pre-set MRI image scan plane for a respective identified site; (d) repeating the identifying and associating steps at least once; (e) registering the model to 3-D MRI imaging space after the identifying step and before introducing an intrabody device into the patient during an MRI guided procedure; (f) guiding the intrabody device to a target intrabody location; (g) electronically tracking the movement of the intrabody device in 3-D image space; (h) automatically electronically using the at least one pre-set scan plane associated with an identified target site when a distal end portion of the intrabody device is determined to be proximate a corresponding location in the heart to obtain near real time MR image data; and (i) displaying near real-time MR images of the target tissue using the obtained MR image data.
The at least one target site (e.g., area of interest) can be a plurality of spaced apart target ablation treatment sites, and wherein the step of displaying the near real-time MR images of tissue being treated can be carried out to show near real-time MR images of tissue being ablated.
The MR images can include a close up view of high resolution MR images of the target tissue in adjacent en face and side views.
The methods may also include: (j) displaying a post-treatment model of the patient's anatomical structure heart; (k) accepting user input to select target sites on the post-treatment model to select at least one additional treatment site for ablation clean-up to facilitate complete lesion pattern formation for electrical isolation; (l) electronically defining a pre-set scan plane for the selected at least one additional treatment site; (m) automatically electronically using the at least one pre-set scan plane associated with the additional target treatment site when a distal end portion of the intrabody device is determined to be proximate a corresponding location in the heart to obtain near real time MR image data; (n) ablating the additional treatment site; and (o) displaying near real-time MR images of the target tissue during the ablating step using the obtained MR image data.
Yet other embodiments are directed to computer program products for facilitating an MRI-guided procedure of a patient. The computer program products include a non-transitory computer readable storage medium having computer readable program code embodied in the medium. The computer-readable program code includes computer readable program code that defines at least one pre-set scan plane for a respective target treatment site in response to a user's marking and/or selection of treatment sites on a model of a patient's target anatomical structure via a User Interface.
The computer product may also include: (a) computer readable program code that provides an interactive model of the patient's anatomical structure to a display; and (b) computer readable program code that generates suggested scan planes that cover tissue associated with a target treatment site based on a contour of tissue proximate the target treatment site.
The computer readable program code can define a plurality of different pre-set scan planes for spaced apart treatment sites associated with an ablation pattern for treatment of cardiac atrial fibrillation.
Still other embodiments are directed to MRI cardiac interventional systems that include: (a) a display; (b) a processor in communication with the display; (c) electronic memory coupled to the processor; and (d) computer program code residing in the memory that is executable by the processor for: (i) displaying a graphical user interface (GUI) containing at least one anatomical map of at least a portion of the heart within the display, wherein the GUI allows a user to select target treatment sites; and (ii) defining associated pre-set scan planes for the selected target treatment sites.
Embodiments of the invention are particularly suitable for MRI-guided cardiac procedure including cardiac EP procedures for ablating tissue to treat arrhythmias such as AFIB or injecting therapeutics to treat heart failure.
The systems may also be suitable for delivering a therapeutic agent or carrying out another treatment or diagnostic evaluation for any intrabody location, including, for example, the brain, heart, gastrointestinal system, genourinary system, spine (central canal, the subarachnoid space or other region), vasculature or other intrabody location.
It is noted that any one or more aspects or features described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. It will be appreciated that although discussed with respect to a certain embodiment, features or operation of one embodiment can apply to others.
In the drawings, the thickness of lines, layers, features, components and/or regions may be exaggerated for clarity and broken lines (such as those shown in circuit of flow diagrams) illustrate optional features or operations, unless specified otherwise. In addition, the sequence of operations (or steps) is not limited to the order presented in the claims unless specifically indicated otherwise.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
It will be understood that when a feature, such as a layer, region or substrate, is referred to as being “on” another feature or element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another feature or element, there are no intervening elements present. It will also be understood that, when a feature or element is referred to as being “connected” or “coupled” to another feature or element, it can be directly connected to the other element or intervening elements may be present. In contrast, when a feature or element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Although described or shown with respect to one embodiment, the features so described or shown can apply to other embodiments.
The term “circuit” refers to an entirely software embodiment or an embodiment combining software and hardware aspects, features and/or components (including, for example, at least one processor and software associated therewith embedded therein and/or executable by and/or one or more Application Specific Integrated Circuits (ASICs), for programmatically directing and/or performing certain described actions or method steps). The circuit can reside in one location or multiple locations, it may be integrated into one component or may be distributed, e.g., it may reside entirely in an MR Scanner control cabinet, partially in the MR Scanner control cabinet, totally in a separate component or system such as a clinician workstation but communicate with MR Scanner electronics and/or in an interface therebetween, in a remote processor and combinations thereof.
The term “pre-set scan plane” refers to scan planes electronically (programmatically) defined for subsequent use by an MRI Scanner as being associated with a location of relevant anatomical tissue of a patient during a MRI guided therapeutic or diagnostic procedure. The pre-set scan planes can be defined based on a volumetric model or map of patient anatomical structure that is subsequently registered or aligned in 3-D imaging space and can be used to acquire near real-time MR image data of patient tissue. The actual pre-set scan planes are typically electronically defined after the model used to select a desired spatial location of a corresponding relevant scan plane is registered to the 3-D imaging space.
The term “map” is used interchangeably with the word “model” and refers to a rendered volumetric visualization or image of target anatomical structure of a patient. For example, a planning map or model can take on any suitable form, including an electrocanatomical map, MRI images, computer segmented model and the like and combinations of same. The term “tissue characterization map” refers to a rendered visualization or image of one or more selected parameters, conditions, or behaviors of cardiac tissue using MR image data, e.g., the tissue characterization map is a rendered partial or global (volumetric) anatomical map that shows at least one defined tissue characteristic of the heart in a manner that illustrates relative degrees or measures of that tissue characteristic(s), typically in different colors, opacities and/or intensities. Notably, the tissue characterization map is to be contrasted with an electroanatomical tissue map which is based on sensed electrical activity of different regions of the heart rather than on MR image data. The planning map and/or subsequent visualizations can use one or both types of volumetric maps. Thus, the planning map and/or visualizations can use one or both types of volumetric tissue maps, shown separately, overlaid on each other and/or integrated (e.g., superimposed) as a composite map. In some embodiments, tissue data from an electroanatomical map and/or the tissue characteristic map can be selectively faded or turned on and off with respect to a pre-acquired map/model of the patient's anatomical structure (e.g., Left Atrium). The terms “fade” and “faded” refer to making the so-called feature less visually dominant in a visualization (e.g., planning map) by dimming the intensity, color and/or opacity relative to other features in the visualization.
The actual visualization can be shown on a screen or display so that the map or anatomical structure is in a flat 2-D and/or in 2-D what appears to be 3-D volumetric images with data representing features or electrical output with different visual characteristics such as with differing intensity, opacity, color, texture and the like, A 4-D map can either illustrate a 3-D heart with movement (e.g., a beating heart and/or a heart with blood flow) or show additional information over a 3-D anatomic model of the contours of the heart or portions thereof.
The term “4-D multiparametric visualization” (4-DMP) means a 4-D visualization (e.g., a 3-D image of a beating heart) with functional spatially encoded or correlated information shown on the visualization. The 4-DMP visualization can be provided with fMRI data and/or one or more tools used to provide the spatially correlated functional data (e.g., electrical, DHE) data of the heart based on a 3-D model. Again, the 3-D, 4-D and/or 4-DMP visualizations are not merely an MRI image or MRI images of the patient but are rendered visualizations that can combine multiple sources of data to provide a visualization of spatially encoded function with anatomical shape. Thus, the visualizations can comprise a rendered model of the patient's target anatomy with a rendered visualization of at least one medical device in an intrabody location with respect to the model and along with near RT MRI image data of the anatomical structure. The figures may include prophetic examples of screen shots of visualizations and the like and do not necessarily represent actual screen shots of a surgical system/display.
The term “close-up” means that the associated image is shown enlarged relative to a global image or map view to show local tissue. The term “high-resolution” means that the image data is obtained with higher resolution than normal image data (usually requiring longer scan times and/or using an internal antenna to increase SNR). For example, the local tissue ablation views may be shown in higher resolution than real-time MRI images in the navigation view. The term en face refers to a view through a tissue wall (e.g., myocardial wall) and substantially parallel (or tangent) to the surface.
The term “programmatically” means that the operation or step can be directed and/or carried out by a digital signal processor, computer program code and/or an Application Specific Integrated Circuit (ASIC). Similarly, the term “electronically” means that the step or operation can be carried out in an automated manner using electronic components rather than manually or using merely mental steps.
The term “target ablation path” describes a desired lesion pattern that is selected to create a desired electrical isolation in the cardiac tissue to treat the at-risk pathology/condition (e.g., AFIB). The target ablation path is not required to be followed in any particular direction or order. The path may include one or more continuous and/or contiguous lesion and/or several non-continuous or non-contiguous lesions. The lesions may be linear (whether straight or with a curvature such as circular or curvilinear). In any one interventional procedure, the physician can define one or more target paths to create the desired pattern/isolation. According to some embodiments, the target ablation path can be used to electronically define associated physical limits associated with the acceptable maximum boundary limits (e.g., width, perimeter and the like) of the target ablation path.
At least a portion of an intrabody medical device is tracked and its position electronically identified in 3-D imaging space (e.g., X, Y, Z coordinates). Various location tracking means for the tool and/or registration means for the catheter to the imaging space can be employed. For example, the intrabody device can include fiducial markers or receive antennas combinations of same. The term “fiducial marker” refers to a marker that can be identified using electronic image recognition, electronic interrogation of MRI image data, or three-dimensional electrical signals to define a position and/or find the feature or component in 3-D space. The fiducial marker can be provided in any suitable manner, such as, but not limited to a geometric shape of a portion of the tool, a component on or in the tool, a coating or fluid-filled coating (or combinations of different types of fiducial markers) that makes the fiducial marker(s) MRI-visible that are active or passive (e.g., if passive, the marker does not provide MR signal) with sufficient intensity for identifying location and/or orientation information for the tool and/or components thereof in 3-D space. As will be discussed further below, in particular embodiments, the device comprises at least one tracking coil electrically connected to a respective channel of the MRI Scanner that generate signals that are detected (received) by the MR Scanner and used to identify respective locations of the coils in a 3-D coordinate system of the imaging space, and hence the device with such tracking coils, in the 3-D image space.
The terms “MRI or MR Scanner” are used interchangeably to refer to a Magnetic Resonance Imaging system and includes the magnet, the operating components, e.g., RF amplifier, gradient amplifiers and operational circuitry including, for example, processors or ASICs (the latter of which may be held in a control cabinet) that direct the pulse sequences, select the scan planes and obtain MR data.
The term “RF safe” means that the catheter and any conductive lead is configured to operate safely when exposed to RF signals, particularly RF signals associated with MRI systems, without inducing unplanned current that inadvertently unduly heats local tissue or interferes with the planned therapy. The term “MRI visible” means that the device is visible, directly or indirectly, in an MRI image. The visibility may be indicated by the increased SNR of the MRI signal proximate the device. The device can act as an MRI receive antenna to collect signal from local tissue and/or the device actually generates MRI signal itself, such as via suitable medical grade hydro-based coatings, fluid (e.g., aqueous fluid) filled channels or lumens. The term “MRI compatible” means that the so-called component(s) is safe for use in an MRI environment and as such is typically made of a non-ferromagnetic MRI compatible material(s) suitable to reside and/or operate in a high magnetic field environment. The term “high-magnetic field” refers to field strengths above about 0.5 T, typically above 1.0T, and more typically between about 1.5T and 10T. Embodiments of the invention may be particularly suitable for 1.5T and/or 3.0T systems.
Embodiments of the present invention can be configured to guide and/or place diagnostic or interventional devices in an MRI environment (e.g., interventional medical suite) to any desired internal region of a subject of interest, including, in some embodiments, to a cardiac location. The subject can be animal and/or human subjects.
Some embodiments of the invention provide systems that can be used to ablate tissue for treating cardiac arrhythmias such as AFIB, and/or to deliver therapeutics such as stem cells or other cardio-rebuilding cells or products into cardiac tissue, such as a heart wall, via a minimally invasive MRI guided procedure while the heart is beating (i.e., not requiring a non-beating heart with the patient on a heart-lung machine).
Generally stated, advantageously, the system can be configured so that the surgical space is the imaging space and the tracking is performed in the imaging space so that there is no requirement to employ a discrete tracking system that must then be registered to the imaging space. In some embodiments, the tracking is carried out in the same 3-D imaging space but the flexible intrabody medical device is tracked independent of the imaging scan planes used to obtain the MR image data for generating images of local anatomy and is shown as a physical representation in the visualization. The system can be configured to work with robotic systems or non-robotic systems.
The term “near real time” refers to both low latency and high frame rate. Latency is generally measured as the time from when an event occurs to display of the event (total processing time). For tracking, the frame rate can range from between about 100 fps (frames per second) to the imaging frame rate. In some embodiments, the tracking is updated at the imaging frame rate. For near ‘real-time’ imaging, the frame rate is typically between about 1 fps to about 20 fps, and in some embodiments, between about 3 fps to about 7 fps. For lesion imaging, a new image can be generated about every 1-7 s, depending on the sequence used. The low latency required to be considered “near real time” is generally less than or equal to about 1 second. In some embodiments, the latency for tracking information is about 0.01 s, and typically between about 0.25-0.5 s when interleaved with imaging data. Thus, with respect to tracking, visualizations with the location, orientation and/or configuration of a known intrabody device can be updated with low latency between about 1 fps to about 100 fps. With respect to imaging, visualizations using near real time MR image data can be presented with a low latency, typically within between about 0.01 ms to less than about 1 second, and with a frame rate that is typically between about 1-20 fps. Together, the system can use the tracking signal and image signal data to dynamically present anatomy and one or more intrabody devices in the visualization in near real-time. In some embodiments, the tracking signal data is obtained and the associated spatial coordinates are determined while the MR image data is obtained and the resultant visualization(s) with the intrabody device (e.g., flexible catheter using the tracking coil data) and the near RT MR image(s) is generated.
In some embodiments, MR image data is obtained during an active treatment such as during an ablation, delivery (e.g., injection) of a drug or other material, valve repair or replacement, lining repair, and the like, and the resultant visualization(s) with the flexible intrabody device used for this treatment (e.g., catheter, needle and the like) along with one or more near RT MR images of local anatomy is substantially continuously generated.
The term “intrabody device” is used broadly to refer to any diagnostic or therapeutic medical device including, for example, catheters, needles (e.g., injection, suture, and biopsy), forceps (miniature), knives or other cutting members, ablation or stimulation probes, injection or other fluid delivery cannulas, mapping or optical probes or catheters, sheaths, guidewires, fiberscopes, dilators, scissors, implant material delivery cannulas or barrels, and the like, typically having a flexible body and/or having a size that is typically between about 5 French to about 12 French, but other sizes may be appropriate. The devices may have multiple active devices, such as multiple ablation electrodes (typically in an array pattern), multiple needles and the like.
The system can allow a user to select a first target site 55 t, select the pre-set associated scan plane(s) in sufficient number to show the relevant tissue thereat, then allow a user to select an additional site 55 t and select the associated scan plane(s), in an incremental fashion. In other embodiments, a user may create or select a treatment pattern 55 p (such as a linear ablation pattern) and the system can identify relevant associated scan planes to be able to image tissue associated with the target treatment pattern 55 p. The model 137 p can be used to place imaging slices on tissue having a certain spatial relationship to a feature (e.g., tip) of a known device 80 and those imaging slices may have certain predefined orientations for most advantageous viewing of the tissue within.
In some embodiments, one or more points, such as a set of points, can be virtually (automatically and/or manually) be placed on the planning map 137 p and can be used to define relevant associated scan plane(s) 141. In some embodiments, one site 55 t can be placed or indicated on the planning map 137 p by a user and the system 10 can automatically suggest one or more planes that cover this site 55 t, and may electronically evaluate local anatomical contour to do so. A clinician may mark fiducials to facilitate the scan plane selection and/or the circuit may be configured to electronically identify anatomical fiducials to identify a position on the model and/or select suggested scan planes associated with a target site that can be used as the actual pre-set scan plane 141 or may facilitate identification or selection of an appropriate scan plane or maybe established as the pre-set scan plane(s) 141.
In other embodiments, a user can define the relevant scan planes for one or more sites on the map 137 p by affirmatively indicating the desired scan plane(s) using the UI (e.g., GUI). In some embodiments, the user can virtually mark two or more points that can be used by the circuit to automatically define the pre-set scan planes 141 used to obtain relevant image slices. The automatically selected/defined pre-set scan planes 141 can be shown visually on/through the model 137 p. A user may adjust the automatically selected scan planes 141 if desired. The UI may be configured to allow the user to affirmatively “lock” a scan plane(s) 141 for each selected site 55 t to electronically associate them with the planning model 137 p for future use by an MR Scanner 10S.
The MRI-guided system that uses the pre-set scan planes 141 can be configured to use a slice thickness that corresponds to that used by the MR Scanner or the scan planes 141 can be generated using an assumed or default slice thickness and/or with a selection of different slice thicknesses.
The target site 55 t can be associated with an area of interest such as an intersection of the left atrium and the esophagus to allow pre-set scan planes that shown this region to avoid damage to the esophagus during an ablation treatment of the LA posterior wall. The target site 55 t can be one or more target treatment sites, e.g., injection or ablation sites. The target site 55 t can also be associated with a target entry location, e.g., for a septal puncture.
The system can register the scan plane locations after registration of the model 137 p to the imaging space. The system can be configured to adjust the scan planes if the MR Scanner 10S uses a different slice thickness or the system can direct the Scanner to adjust its operational commands to use the slice thickness used to set the pre-set scan planes 141. The system can be configured to visually generate a suggested scan plane(s) 141 on the model 13′7 p that will provide a suitable image slice that covers the selected site 55 t.
In certain embodiments, the planning map 137 p is used to identify relevant target sites 55 t and associated scan planes 141 (shown as one projected scan plane in
Once the planning model 137 p is registered to the MRI imaging space for the MRI-guided procedure, the scan planes 141 tied to the planning model 13′7 p are then electronically spatially adjusted to the locations in the MRI 3-D imaging space. Thus, the system 10 can be configured to import the planning map 137 p, electronically automatically or manually (via a clinician using the display) register it to the 3-D MRI imaging space.
The system 10 (
In other embodiments, the planning map 137 p is registered to the 3-D MRI imaging space prior to selection or identification of the at least one target site 55 t and/or pattern 55 p and the scan planes 141 are then automatically correctly associated with the imaging space and the MRI scanner 10S.
In certain embodiments, during the MRI-guided procedure, the system 10 (e.g., circuit 60 c) can interact with the intrabody device 80 to select a relevant pre-set scan plane 141 (coronal, sagittal, transverse) corresponding to a tracked location of a distal end portion of the intrabody device. In some embodiments, the pre-set scan plane(s) 141 used during the MRI-guided procedure is selected based on defined projected distance at and/or beyond a distal tip of the intrabody device 80 (axial and/or perpendicular to the distal end portion of the device or substantially parallel to tissue thereat) in near real time during an MRI-guided surgical procedure.
In certain embodiments, the system 10 (typically circuit 60 c) (
A user/clinician can select the proposed or suggested pattern 55 p and/or adjust the pattern on the map 137 p by adding, moving or removing portions of the default ablation sites 55 t shown on the planning image 137 p. For example, if a user selects Procedure A, a suggested default ablation pattern can be shown on the planning map 137 p with the clinical goal to provide electrical isolation of the pulmonary veins and a posterior wall of the left atrium.
Thus, in some embodiments, a user can select a relevant “procedure” from a pre-defined list such as a pull-down menu or other user interface (UI), typically a GUI (graphical user interface) for a patient which can allow a user to cause the system to display a corresponding suggested treatment (e.g., ablation) pattern. If satisfactory (which can be affirmatively indicated by a clinician), the system can then electronically evaluate patient structure (contour) and generate suggested scan planes that provide image slices that cover relevant anatomical locations. The system/circuit can suggest a minimum number of scan planes 141 that cover the patient geometry in the at least one target site 55 t.
In some embodiments, the system/circuit can be configured to generate a grid or template 55 g (
The UI control 25 c that can be configured to allow a physician or other clinician to select a region of interest in the map 137 p by placing a mark, cursor, pen, or by touching the screen at a region of interest. This can cause the system to define a target site 55 t and electronically define preset scan planes for use during an interventional procedure. The circuit 60 c can use the map 137 p to define one or a plurality of different scan planes, such as between one (1)-six (6) scan planes. In practice, more or less scan planes may be used for a particular path or ROI (portion) of a heart. Any scan plane can be temporarily disabled to allow faster update of the remaining scan planes.
As shown in
The workstation 60 can include the circuit 60 c (e.g., ASIC and/or processor with software) that includes or executes part or all of the computer readable program code for generating the pre-set scan planes and/or identifying the pre-set scan planes. However, part or all of the circuit 60 c can reside in the MRI Scanner 105, the interface 44 (where used) and/or in one more remote processors.
Optionally, an MRI scanner interface 44 may be used to allow communication between the workstation 60 and the scanner 105. The interface 44 may reside partially or totally in the scanner 10S, partially or totally in the workstation 60, or partially or totally in a discrete device (shown in broken line in
As shown in
The tracking members 82 can comprise miniature tracking coils, passive markers and/or a receive antenna. In a preferred embodiment, the tracking members 82 include at least one miniature tracking coil 82 c that is connected to a channel 10 ch of an MRI Scanner 10S (
Embodiments of the present invention provide a new platform that can help facilitate clinical decisions during an MRI-guided procedure and can present real anatomical image data to the clinician in a visualization 100 v. The visualizations 100 v (
The term “physical representation” means that a device is not actually imaged but rather rendered with a physical form in the visualizations, typically with a three-dimensional shape or form. Typically, the physical representation is a partial physical representation which shows the distal end portion of the device in the body in the 3-D MR image space. The physical representation may be of any form including, for example, a graphic with at least one geometric shapes, icons and/or symbols. In some particular embodiments, the physical representation may be a virtual graphic substantial replica substantially corresponding to an actual shape and configuration of the actual physical appearance and/or configuration of the associated device (see, e.g.,
The term “tortuous” refers to a curvilinear pathway in the body, typically associated with a natural lumen such as vasculature. The term “dynamic visualizations” refers to a series of visualizations that show the movement of the device(s) in the body and can show a beating heart or movement based on respiratory cycle and the like.
The term “pre-acquired” means that the data used to generate the model or map of the actual patient anatomy can be obtained prior to the start of an active therapeutic or diagnostic procedure and can include immediately prior to but during the same MRI session or at an earlier time than the procedure (typically days or weeks before).
Embodiments of the present invention can be configured to guide and/or place intrabody diagnostic and/or interventional devices in an MRI environment (e.g., interventional medical suite) to any desired internal region of interest of a subject, typically via a natural lumen and/or tortuous path so that the intrabody devices can take on different non-linear configurations/shapes as it moves into position through a target pathway (which may be a natural lumen or cavity). The subjects can be animal and/or human subjects.
Some embodiments of the invention provide systems that can be used to ablate tissue for treating arrythmias such as AFIB, to repair or replace cardiac valves, repair, flush or clean vasculature and/or place stents, and/or to deliver stem cells or other cardio-rebuilding cells or products into cardiac tissue, such as a heart wall, via a minimally invasive MRI guided procedure while the heart is beating (i.e., not requiring a non-beating heart with the patient on a heart-lung machine). The cardiac procedures can be carried out from an inside of the heart or from an outside of the heart. Thus, some embodiments are directed to cardiac procedures for treating cardiac arrythmias or heart failure (e.g., congestive heart failure, reduced heart function, and the like).
Thus, the map 137 p for cardiac procedures can be an electroanatomical map, a tissue characterization map, or combinations of shame of at least a portion of the patient's heart. Typically the map is rendered to represent portions or regions of the heart, such as the left atrium and any adjacent vasculature of interest (e.g., the branching of the pulmonary veins), the ventricles and the like.
Other embodiments provide systems suitable for delivering a therapeutic agent or carrying out another treatment or diagnostic evaluation for any intrabody location, including, for example, the brain, gastrointestinal system, genourinary system, spine (central canal, the subarachnoid space or other region), vasculature or other intrabody locations. Additional discussion of exemplary target regions can be found at the end of this document. To be clear, while detailed drawings of exemplary flexible devices 80 are shown for tracking coils for transseptal needles (septal puncture kit components) and mapping and/or ablation catheters for cardiac use, embodiments of the invention are not intended to be limited to these devices nor to cardiac use. Exemplary devices are listed above. Exemplary (non-cardiac) intrabody locations are listed at the end of this document. For example, the device can be implemented as injection catheters or diagnostic biopsy needles and the like for any target anatomical location in the body. See, e.g., U.S. patent application Ser. No. 10/769,994 (intramyocardial injection needle), U.S. Pat. No. 7,236,816 (biopsy needle), and U.S. Pat. No. 6,606,513 (transseptal needle), the contents of which are hereby incorporated by reference as if recited in full herein.
The system 10 and/or circuit 60 c can calculate the position of the tip of the device 80 t as well as the shape and orientation of the flexible device based on a priori information on the dimensions and behavior of the device 80 (e.g., for a steerable device, the amount of curvature expected when a certain pull wire extension or retraction exists, distance to tip from different coils 82 and the like). Using the known information of the device 80 and the tracking signals (which are spatially associated with the same X, Y, Z coordinate system as the MR image data) the circuit 60 c can select a scan plane(s) from one of the pre-set scan planes 141 that is most closely correlated to the location of the distal end of the device to rapidly generate visualizations showing a physical representation of the location of a distal end portion of the device 80 with near RT MR images of the anatomy.
In some embodiments, the tracking signal data is obtained and the associated spatial coordinates are determined while a circuit 60 c in the MRI Scanner 10S (
The tracking coils 82 c can each include a tuning circuit that can help stabilize the tracking signal for faster system identification of spatial coordinates.
In some embodiments, each tracking coil 82 c can be connected to a coaxial cable 81 having a length to the diode via a proximal circuit board (which can hold the tuning circuit and/or a decoupling/matching circuit) sufficient to define a defined odd harmonic/multiple of a quarter wavelength at the operational frequency of the MRI Scanner 10S, e.g., λ/4, 3λ/4, 5λ/4, 7λ/4 at about 123.3 MHz for a 3.0T MRI Scanner. This length may also help stabilize the tracking signal for more precise and speedy localization. The tuned RF coils can provide stable tracking signals for precise localization, typically within about 1 mm or less. Where a plurality (e.g., two closely spaced) adjacent tracking coils are fixed on a substantially rigid material, the tuned RF tracking coils 82 can provide a substantially constant spatial difference with respect to the corresponding tracking position signals.
The tracking sequence used in the system 10 can intentionally dephase signal perpendicular to the read-out direction to attenuate unwanted signal from 1) bulk objects and 2) regions sensed by other signal sensitive parts of the catheter which couple to the tracking coil (e.g. the coaxial cable along the catheter shaft). This tends to leave only a sharp peak indicating the position of the tracking coil.
The tracking sequence block can include or consist of a plurality of (typically about three) repetitions of a small flip-angle excitation. Each repetition is designed to indicate the x, y or z component of the tracking coil coordinates in succession. Frequency encoding is used along the x-direction to obtain the x-coordinate, the y-direction for the y-coordinate, and the z-direction for the z-coordinate. When the frequency encoding is in the x-direction, the other two directions (y and z) are not spatially encoded, producing projection (spatially integrated) signals in those directions from all excitation regions. The dephasing gradient attempts to attentuate unwanted signal included in these projections. Once the tracking sequence block is complete, a spoiler gradient can be used to dephase any transverse signal remaining from the tracking before the imaging sequence block is executed.
The imaging sequence block obtains a portion, depending on the acceleration rate, of the data used to reconstruct an image of a single slice. If the acceleration rate is 1, then all of the data for an image is collected. If the acceleration rate is 2, then half is collected, etc. If multiple slices are activated, then each successive imaging block collects data for the next slice, in ‘round robin’ fashion. If any magnetization preparation (e.g., saturation pulses) are activated, these are executed after the tracking sequence block, immediately before the imaging sequence block.
Additional discussion of tracking means and ablation catheters can be found in U.S. Pat. No. 6,701,176, and U.S. Provisional Application Ser. No. 61/261,103, the contents of which are hereby incorporated by reference as if recited in full herein. Exemplary ablation catheters will be discussed further below.
Referring now to
The circuit 60 c can be configured to generate the visualizations 100 v with at least two visual reference planes 41, 42 (shown with a third intersecting plane 43) that are oblique or orthogonal to each other and extend through at least a major portion of the visualization 100 v. The planes 41, 42 (and 43) can be transparent and/or translucent. They may be shown with different color perimeters that correspond to a respective two-dimensional image slice (which may be shown as thumbnails on the display also with a perimeter of similar or the same color).
The planes 41, 42 can move relative to each other in the imaging space or may be locked together, in any case they can be configured to move relative to the model 100M in the imaging space. As shown in
In some embodiments, as shown in
As shown in
The UI 25 typically includes multiple GUI controls that can include a touch screen input control to allow a clinician/physician to select a region of interest in the map 100M by placing a cursor or by touching the screen at a region of interest. This can cause the system to obtain real time MR image data of that region and provide the associated image on the display and/or define scan planes (which may be preset scan planes 141) at that location in space.
Referring again to
The UI 25 can be configured to allow a user to zoom, crop, rotate, or select views of the displayed map 30 (also interchangeably identified as 100M herein). As shown, one GUI control 25 c can be a slide control 50, on a lower portion of the display 20 that can allow a user to select whether to display RT-MRI (Real Time MRI images) 51 or a tissue characterization map 30, or combinations thereof (e.g., the slide can allow a fade-away display between the two types of images). The GUI control 50 may also be a toggle, a touch screen with direction sensitivity to pull in one direction or other graphic or physical inputs.
The circuit 60 c can also be configured to generate MRI images which show the device location in near real time (in the MR image space). The UI 25 can also be configured to allow a user to turn off and/or fade the renderings of the device 80 in and out of the visualizations with rendered views of the device versus actual images of the device to confirm location or for additional visual input. The device may include other fiducial markers (e.g., a passive marker or an active marker such as receive antenna) for facilitating the visual recognition in the MR image.
The UI 25 can include a list of user selectable patient-specific images and/or maps 30 including a plurality of tissue maps, typically including at least one, and more typically, several types of, tissue characterization maps (or data associated with such maps) associated with the procedure that can be selected for viewing by a user. The UI 25 can also include GUI controls that allow a user to select two or more of the tissue characteristic maps, with such data able to be shown together (overlaid and registered and/or as a composite image) or separately. As shown, the maps 30 may include at least a plurality of the following:
(a) a regional evaluation tissue characterization map 32 which shows actual lesion patterns in one region to allow a clinician to view regional (ablation) information (such as at the LA (left atrium), a PV (pulmonary vein) and the like) and/or a global evaluation tissue characterization map 32;
(b) pre-procedure MRI cardiac scans 34;
(c) DHE 1 (Delayed Hyper Enhancement) tissue characterization map 35 a taken at a first point in time (such as a week or just prior to the procedure);
(d) DHE 2 tissue characterization map 35 b taken at a second point in time, such as during a procedure, potentially toward an end of the procedure to confirm complete electrical isolation of the PV (pulmonary veins) or other targets prior to terminating the procedure—alternatively the DHE 2 map can be associated with the end of a prior EP ablation procedure;
(e) an EA (electroanatomical) map 35 c;
(f) an edema tissue characterization map 35 d;
(g) other tissue characterization maps, for example:
(h) at least one procedure planning map 137P with target sites 55 t (
(i) device views 36 that show the physical representation of the device 80R in the surgical/imaging space, e.g., with an ablation catheter 36 a shown in position and/or a mapping (loop) catheter 36 b as devices 80R shown in position (
The display UI 25 can be configured to allow a physician or other clinician to select whether to show real time MR images of target tissue either in the tissue map and/or in a separate view or window. The UI 25 typically includes multiple GUI controls that can include a touch screen input control to allow a clinician/physician to select a region of interest in the tissue characterization map by placing a cursor or by touching the screen at a region of interest. This can cause the system to obtain near real time MR image data of that region and provide the associated image on the display and/or use preset scan planes associated with that location in the imaging space.
Pre-acquired tissue characterization maps 30 are typically registered to 3-D coordinate space so that the relevant scan planes used to obtain MR image data obtained from the patient during a procedure can be pre-set as discussed above. Data associated with one or more of the tissue characterization maps can be updated over time (including in near real time) using MR image data automatically or upon request by a user. The tissue maps can also be obtained during the procedure so that the MR image data is in the 3-D MRI image space. EA maps can be imported or generated using tracking and/or mapping catheters in the 3-D MRI image space, the latter of which may provide a more accurate or timely EA map (without requiring registration of a pre-acquired map).
The tissue characteristic map(s) 30 can be generated using MR image data that shows normal and abnormal status, conditions and/or behavior of tissue (such as in response to a therapeutic treatment). For example, the tissue characterization map(s) 30 can show a thermal profile in different colors (or gray scale) of cardiac tissue in a region of interest and/or globally. In other embodiments, the tissue characterization map 30 can illustrate one or more of infarcted, injured, necrotic, hypoxic, ischemic, scarred, edemic (e.g., having edema) and/or fibrotic tissue or otherwise impaired, degraded or abnormal tissue as well as normal tissue on an anatomical model of the heart. In yet other embodiments, the tissue characterization map can illustrate portions of the heart (e.g., LA or posterior wall) with lesser or greater wall motion, and the like.
In some embodiments, the system can be used to deliver a therapeutic to target anatomy using an injection needle or fluid delivery cannula. A fluid distribution map or data therefrom can be shown on the model 100M or in the MRI image 100MRI (without requiring the rendered model). For example, to treat heart failure, a therapeutic agent can be injected into one or more target locations in infarct or abnormal cardiac tissue. Typically, the injection is carried out in several spots to generate a desired coverage pattern or area/volume. The fluid distribution map can be used to confirm that desired coverage of the cardiac tissue was obtained based on the injections. If not, another (“clean-up”) target site or sites can be identified and the sites can be injected with the therapeutic agent. In other embodiments, a previous injection site may need additional volumes of the agent, so that same site can be treated again. The fluid distribution map can be generated based on MRI image data alone. In other embodiments, a fluid distribution map can be generated based on a known injection site or sites, and a known volume of injected agent (which may be measured in situ or based on a known flow rate and known time of injection). This data can be used to generate an estimated fluid distribution map. In other embodiments, a fluid distribution map can be generated based on both MR image data and injection amounts. In some embodiments, the system/circuit 60 c can indentify a spatial grouping of injection sites and electronically select a scan plane or scan planes that can be set through the injection sites to obtain near RT MRI image data or obtain image data after the injections (such as for a regional or global coverage evaluation prior to the end of the MRI-guided procedure). For cardiac injections for some heart repairs, a planning map 37M identifying infarct tissue and normal (healthy) tissue boundaries can be used to identify target injection sites 55 t. This map 37M can be registered to the MRI image space. A target site 55 t can be associated with the X, Y, Z location in the MRI image space. Near RT images 100MRI can be generated during the injections (similar to the ablations) to allow a physician to see “live” the injection distribution or disbursement. This fluid distribution map can be electronically provided as a data set that can be selectively shown on the anatomical model 100M. The therapeutic agent can be any suitable agent including, for example, stem cells (and may be directed to rebuilding cardiac tissue) and is MRI visible.
Other embodiments can generate light exposure maps to evaluate optical light exposure of target tissue (or light activated drugs in such tissue) similar to the fluid distribution map discussed above. The light exposure map can be based on an internal laser or other light source that exposes the tissue to non-ablative energy.
Whether a parameter or tissue characteristic is shown in the tissue characteristic map as being impaired, degraded or otherwise abnormal or affected by a treatment versus normal or untreated can be based on the intensity of pixels of the tissue characteristic in the patient itself or based on predefined values associated with a population “norm” of typical normal and/or abnormal values, or combinations of the above.
Thus, for example, normal wall motion can be identified based on a comparison to defined population norms and different deviations from that normal wall motion can be shown as severe, moderate or minimal in different colors relative to tissue with normal wall motion.
In another example, a thermal tissue characterization map can illustrate tissue having increased temperatures relative to other adjacent or non-adjacent tissue. Thus, for example, during or shortly after ablation, the lesioned tissue and tissue proximate thereto can have increased temperatures relative to the non-lesioned temperature or tissue at normal body temperatures. Areas or volumes with increased intensity and/or intensity levels above a defined level can be identified as tissue that has been ablated. The different ablation sites 55 t can be shown on the map 30 as areas with increased temperatures (obtained at different times during the procedure) and incorporated into the thermal tissue characterization map 30 automatically and/or shown upon request.
In some embodiments, the tissue characteristic map 30 uses MR image data acquired in association with the uptake and retention of a (e.g., T-1 shortening) contrast agent. Typically, a longer retention in tissue is associated with unhealthy tissue (such as infarct tissue, necrotic tissue, scarred tissue and the like) and is visually detectable by a difference in image intensity in the MR image data, e.g., e.g. using a T1 weighted sequence, to show the difference in retention of one or more contrast agents. This is referred to as delayed enhancement (DE), delayed hyper-enhancement (DHE) or late gadolinium enhancement (LGE).
The map 100M is typically a volumetric, 3-D or 4-D anatomical map that illustrates or shows tissue characterization properties associated with the volume. The map can be in color and color-coded to provide an easy to understand map or image with different tissue characteristics shown in different colors and/or with different degrees of a particular characterization shown in gray scale or color coded. The term “color-coded” means that certain features or conditions are shown with colors of different color, hue or opacity and/or intensity to visually accentuate different conditions or status of tissue or different and similar tissue, such as, for example, to show lesions in tissue versus normal or non-lesion tissue or injected fluid locations and coverage/distribution.
In some embodiments, the UI 25 can be configured to allow a clinician to increase or decrease the intensity or change a color of certain tissue characterization types, e.g., to show lesion tissue or tissue having edema with a different viewing parameter, e.g., in high-contrast color and/or intensity, darker opacity or the like. A lesion site(s) in the tissue characteristic map 30 can be defined based on an ablation position in three-dimensional space (e.g., where an electrode is located based on location detectors, such as tracking coils, when the ablation electrode is activated to ablate), but is typically also or alternately associated with MRI image data in associated scan planes to show an ablation site(s) in an MRI image. The MR image data may also reflect a change in a tissue property after or during ablation during the procedure, e.g., DHE, thermal, edema and the like.
The circuit can be configured to generate a difference or a comparison map that is generated from a pre-procedure or start-of procedure tissue characterization map and an intra-procedure tissue characteristic map to show the differences based on the procedure. The “before” and “after” maps can be electronically overlaid on a display and shown in different colors, opacities and/or intensities or corresponding pixel values from each image in a ROI can be subtracted to show a difference map. Again, the UI 25 can allow a clinician to select or deselect (or toggle between) the before or after tissue characterization maps or adjust display preferences to allow a visual review of differences.
A regional update tissue characterization map 32 can be used to evaluate whether ablated locations have the desired lesion formation. The UI 25 can allow the clinician to request a high resolution or enlarged view of the actual ablated tissue merely by indicating on the regional evaluation tissue characterization map a desired region of interest (e.g., by pointing a finger, cursor or otherwise selecting a spot on the display). For example, a high resolution MR image of suspect tissue in the LSPV can be shown so that the physician can see actual tissue in the desired spot indicated on the tissue characterization map. New targets can be marked on the map as needed and again, pre-set scan planes can be automatically associated with the new targets by location.
The MRI Scanner 10 can be operated substantially continuously to provide image data that can be used to generate updated tissue characteristic maps upon request or automatically. This operation can be “in the background”, e.g., transparent to the user so as not to slow down the procedure while providing updated image data during the course of the procedure.
The scan planes used to generate the MR images for the active treatment (e.g., ablation) views can be automatically determined based on the known position of the tracking coils in 3-D imaging space. The scan planes used for the active treatment views of the near RT images may be pre-set scan planes 141 that are electronically automatically selected based on the determined location of one or more tracking coils 82 c when it is in proximity to a corresponding location of a defined target site 55 t that was previously identified (such as on planning map 137 p that was subsequently registered to the MRI imaging space).
In some embodiments, the system includes a navigation view mode and an ablation view mode for cardiac procedures. The latter viewing mode can automatically be shown on the display 20 during an active ablation. The circuit 60 c can electronically define pre-set scan planes 141 associated with a respective target ablation site 55 t which is correlated (registered) to an actual location in 3-D space which is then electronically stored in electronic memory as default pre-set scan planes 141 for that target location 55 t. The near RT MRI images in active therapy-view mode can automatically be displayed when the ablation/injection or mapping catheter reaches the corresponding physical location in the heart during the procedure. The planned target sites 55 t can also used to define the physician view (3-D perspective), e.g., a preset view, whenever the ablation catheter is in the location associated with the target site. Thus, the target sites 55 t identified in the planning tissue characterization map 137 p can be used to preset both associated scan planes for the near real time MRI and the 3-D perspective view for display without requiring further clinician input.
During some cardiac procedures, as the ablation catheter approaches a location that corresponds to a target ablation site 55 t, the circuit 60 c (e.g., MR Scanner) can cause or direct the selected scan planes to “snap to” the catheter tip location using the preset scan planes defined for that location to obtain real-time MR image data of the associated tissue. The scan planes can be adjusted in response to movement of the ablation catheter (as typically detected by tracking coils) prior to active delivery (e.g., ablation) if the physician decides the location is unsatisfactory. In some embodiments, the snap-to scan plane(s) can be carried out based on the position of two closely spaced tracking coils 82 c on a distal end of the device 80. The two coils 82 c can be held on a relatively rigid substrate or catheter end with between about 2-10 turns/coil. The tracking coils 82 c can be connected via a respective coaxial cable to the MR scanner 10S as noted above. The snap-to or projected scan plane can be projected a distance beyond the calculated tip location, such as between about 0-4 mm as discussed above. This embodiment may be particularly suitable for a deflectable end ablation catheter. In other embodiments, such as for a loop catheter, the tracking coils 82 c can be held on a loop end of the device and reside on a common plane. The circuit 60 c can be configured to define the plane based on the location of at least three of the tracking coils 82 c. The tissue-device interface for the snap-to location can be selected to be parallel and proximate the identified plane (e.g., between about 0-4 mm from the plane). In yet another embodiment, a device can have between about 1-20 tracking coils along its length (e.g., along a distal end portion thereof). The snap-to location can be based on a location that is tangent and in-line with at least two of the tracking coils (as the device may deflect and the position of at least some of the tracking coils may change relative to each other).
The circuit 60 c can adjust the scan planes as needed if the physician moves the ablation catheter to obtain slices that show the ablation of the lesion including side and en face views showing substantially real-time MRI of the tissue being ablated. The slices can include a view generated axially along the line of the catheter and projecting forward a defined distance into tissue for the side view (e.g., beyond the tip of the device such as between about 0-4 mm, typically about 1-2 mm). In some embodiments, the system may automatically enable or disable ECG gating as necessary when defining scan planes, markers, recording electrograms, and the like.
For an optimal or proper en face view the scan plane can be oriented to a plane that is substantially parallel to the target tissue surface (e.g., proximate a tip of the device). This can be done based on coordinates of the 3D segmentation/model relative to the tip position.
To obtain a slice with a relevant scan plane for the en face view, the device tip can be used to define one point and the circuit could identify a plurality of additional points (e.g., about three more points) on the surface of the model 100M. Those additional points can be a short radius away from the device tip (i.e., similar to a spoke and wheel pattern). Distance of the (three) radial points should be closely spaced relative to the center point, particularly for curved tissue surfaces (e.g., the cardiac walls being ablated or otherwise treated will usually be curved, and in some cases, even have complex curves like the PV ostia). Choosing this distance may be made with reference to typical human cardiac anatomy, the distance of those points may be between about 3 to 5 mm. In some particular embodiments, the following steps may be used to obtain the en face views.
It is noted that the above steps may not be suitable where the device is a loop catheter. When using a loop catheter as the intrabody device with the tracking coils, the physician typically ablates on the inside of the loop and the circuit can use the coordinates of the tracking coils on the loop catheter to describe the scan plane for the en face view.
In some embodiments, the system can keep track of the shortest line from the tip of the device to the registered model, and can even display this line in near real-time in the rendering(s). Then, with user input, e.g. on a button press, the circuit 60 c can define a plane tangent to the model surface for the en face view, or along this line for the axial view. Gating may be used. The axial view may be more robust as it cuts through the wall.
In addition to continuous collection of “new” image data, the data can also be processed by algorithms and other means in order to generate and present back to the surgeon in near real-time or upon request, a substantially continuously updated, patient specific anatomical tissue characterization map of a portion of the heart of interest.
During ablation MR thermometry (2-D) can be used to show real-time ablation formation taking a slice along the catheter and showing the temperature profile increasing. It is contemplated that 2D and/or 3D GRE pulse sequences can be used to obtain the MR image data. However, other pulse sequences may also be used.
In some embodiments, an EA (electroanatomical) map can be obtained prior to (typically immediately prior to) the actual interventional MRI-guided procedure either while the patient is in the MRI scanner or from an X-ray based system from which the EA map can be registered to a tissue characteristic map 30 and shown on the display 20. In some embodiments, the tissue characterization map can include, incorporate, overlay or underlay data from an electroanatomical map (which may be imported from an X-ray imaging modality or generated in an MRI Scanner) to define an integrated electro and tissue characterization combination map. The electrical activity can be detected via electrical activity sensors that can detect impedance or other electrical parameter that can sense fractionated or normal electrical activity in cardiac tissue as is known to those of skill in the art. If so, the electroanatomical map can be registered to the tissue-characterization map so that MR data updates using MR data that is generated during the intervention can be generated and displayed on the integrated map.
Also, the UI 25 can be configured to allow a clinician to select or deselect the electroanatomical map (where used) so that the information from the electroanatomical map is electronically stripped or removed (and/or added back in) to the tissue characteristic map as desired. In other embodiments, the tissue characterization map is maintained separate from the electroanatomical map, and if used, the electroanatomical map is shown in a separate window or screen apart from the tissue characterization map.
In some embodiments, the device-tissue interface 100 i (
In some particular embodiments, during navigation mode (rather than an ablation mode), the catheter 80 can be visualized using a different pulse sequence from that used in the high-resolution ablation mode, such as, for example, an RT MRI sequence using GRE or SSFP (e.g., TrueFISP) pulse sequence with about 5.5 fps), the tracking coils 82 c can be used for spatial orientation and positioning. Typical scan parameters for (near) real-time include: echo time (TE) 1.5 ms, repetition time (TR) 3.5 ms, flip angle about 45 degrees or about 12 degrees, slice thickness 5 mm, resolution 1.8 mm×2.4 mm, parallel imaging with reduction factor (R) of 2. For near real-time imaging with SSFP, a typical flip angle is about 45 degrees.
Once the device position is deemed appropriate (using tracking coils 82 c), a pulse sequence at the associated scan plane can be used to generate high resolution visualization of the catheter tip 80 t and (myocardial) tissue interface. For example, a T1-weighted 3D FLASH sequence (Tlw FLASH) as noted above. Myocardial or other target tissue images during ablation or other therapy can be acquired using an Inner Volume Acquisition (IVA) dark-blood prepared T2-weighted HASTE (T2w HASTE) or dark-blood prepared Turbo Spin Echo (TSE) sequence. Examples of HASTE and TSE sequence parameters include: TE=79 ms/65 ms, TR=3 heart beats, 3 contiguous slices with thickness of about 4 mm, resolution 1.25 mm×1.78 mm/1.25 mm×1.25 mm, fat saturation using SPAIR method, and parallel imaging with R=2, respectively.
Typical heart beat rates and free breathing can present imaging challenges. In some embodiments, (near) RT navigation imaging slices (e.g., GRE pulse sequence at 5.5 fps) can be aligned with high-resolution tissue interface slices (e.g., T1 w FLASH) for visualization of the catheter-tissue interface. Subsequently, those slices obtained with Tlw FLASH can be aligned with those obtained with dark-blood prepared T2w Haste images for myocardial tissue/injury characterization during energy delivery. This stepwise approach can allow confident localization of specific points within the atrium and while ablating tissue and simultaneously visualizing the tissue for near-real time assessment of tissue injury associated with lesion formation. It is also noted that the sequences described herein are provided as examples of suitable sequences and it is contemplated that other known sequences or newly developed sequences may be used for cardiac ablation or other anatomy or interventional procedures.
In some embodiments, slices acquired with different sequences can be interlaced to provide an interactive environment for catheter visualization and lesion delivery, a UI can allow a user to toggle between these views or can alternate the views based on these image slices or navigation versus ablation or other interventional modes/views.
As is known to those of skill in the art, there are typically between about 60-100 lesions generated during a single patient cardiac (AFIB) EP procedure. Other cardiac arrythmia procedures may only require about 1 ablation or less than 60. A typical patient interventional cardiac procedure lasts less than about 4 hours, e.g., about 1-2 hours. Each lesion site can be ablated for between about 30 seconds to about 2 minutes. Linear transmural lesions (such as “continuous” drag method lesions) may be generated and/or “spot” lesions may be generated, depending on the selected treatment and/or condition being treated. The continuous lesion may be formed as a series of over lapping spot ablation lesions or as a continuous “drag” lesion.
The system can include a monitoring circuit can automatically detect which devices are connected to the patient patch bay. One way this can be achieved is by using ID resistors in the patch bay and/or interface as well as in various devices that connect thereto. The MRI scanner computer or processor or the clinician workstation module or processor can monitor resistors via connections CON1, CON2 and CON3. The devices 80 (
Electrical isolation between the MR Scanner 10S and the device 80 can be provided via low pass filters inside and outside the MRI suite. As is known to those of skill in the art, components in the MRI Suite can be connected to external components using a waveguide built into the RF shield that encloses the MRI suite. The ablation catheter 80 can be connected to an appropriate energy source, such as, for example, a Stockert 70 RF generator (Biosense Webster, Diamond Bar, Calif., USA) with MR compatible interface circuits configured for 3T magnetic fields (where a 3T system is used). The system can comprise an EP Suite with a Siemens Verio system (Siemens Healthcare, Erlangen, Germany) or other suitable scanner as well as suitable external imaging coils, such as spine and/or body array coils as is known to those of skill in the art. Other ablation catheters including balloon (cryoablation), laser, ultrasound and the like may also be used in lieu of or with the RF electrode ablation catheter. Other therapeutic catheters or devices may be used including an injection needle catheter and the like.
The catheter 80A can be configured to reduce the likelihood of undesired deposition of current or voltage in tissue. The catheter 80A can include RF chokes such as a series of axially spaced apart Balun circuits or other suitable circuit configurations. See, e.g., U.S. Pat. No. 6,284,971, the contents of which are hereby incorporated by reference as if recited in full herein, for additional description of RF inhibiting coaxial cable that can inhibit RF induced current.
The device 80A tracking coils 112, 114 (
In some embodiments, the ablation tip 80 t is provided with one or more exit ports 132 (
In some embodiments, a pull wire 136 (
As discussed above with respect to
In some embodiments of the present invention, RF tracking coils 112, 114, 122, 124 may be between about 2-16 turn solenoid coils, typically 2-10 turn solenoid coils. However, other coil configurations may be utilized in accordance with embodiments of the present invention. Each of the RF tracking coils 112, 114, 122, 124 can have the same number of turns or a different number of turns, or different ones of the RF tracking coils 112, 114, 122, 124 can have different numbers of turns. It is believed that an RF tracking coil with between about 2-4 turns at 3.0 T provides a suitable signal for tracking purposes.
Embodiments of the present invention may be utilized in conjunction with navigation and mapping software features. For example, current and/or future versions of devices and systems described herein may include features with adaptive projection navigation and/or 3-D volumetric mapping technology, the latter may include aspects associated with U.S. patent application Ser. No. 10/076,882, which is incorporated herein by reference in its entirety.
The preset scan planes can be defined based on a UI that allows a clinician/physician to touch a screen to mark/indicate or otherwise select target ablation sites on the planning map of the patient's anatomical structure of interest. Alternatively or additionally, a selectable list of procedures for particular conditions which having defined treatment sites can be provided and a user can select the corresponding procedure for the patient whereby, in response, suggested treatment sites can be electronically shown on the planning map (block 302). Alternatively or additionally, the system can apply an adjustable grid or template that can be electronically adjusted via a user or automatically morphed to fit patient-specific tissue contour (block 304).
The planning map can comprise data from one or more of a tissue characterization map and/or an electroanatomical map. A clinician can generate the target treatment sites on the planning map outside 3-D image space used for the MRI guided procedure and the map with the associated pre-set scan planes can subsequently be registered to the 3-D image space.
The system can electronically register the planning map to the MRI 3-D image space (using manual alignment or automatic alignment) proximate in time to initiating the MRI-guided procedure and electronically adjust the identified pre-set scan planes associated with the planning map (block 322). The MRI Scanner can use one or more of the pre-set scan planes to obtain near real-time MRI image data during the MRI guided procedure.
During the MRI-guided procedure, the location of an intrabody device (e.g., intracardiac ablation catheter) can be tracked and a physical representation of the device rendered and shown in a visualization with respect to the registered map (block 315). As the distal end of the intrabody device (e.g., a tip electrode) approaches the proximity of one of the previously indicated target locations or resides proximate one of the selected target sites identified by the planning map, the MRI Scanner is directed to scan (“snap to”) relevant local tissue using the associated preset scan plane(s) (block 320). Optionally, the MR Scanner can be programmatically directed to select scan planes that includes a slice that is aligned with an axial direction of the ablation catheter and that projects forward from the distal tip of the device (block 322). That is, a device-tissue interface location proximate a tip location of the device in the three dimensional image space is electronically calculated using the identified locations of the tracking coils. The calculating step projects axially forward a defined distance beyond the tip to define the device-tissue interface and at least one scan plane used to obtain the MR image data for the near RT images during and/or proximate in time to delivery of a therapeutic treatment and/or a diagnostic procedure is electronically defined using the calculated location. A user (via a UI) may be able to select the desired projection forward distance for the scan plane/slice location. The system may include a default distance (e.g., the end of the tip or distance forward=about 0 or 0.1 mm) that can be adjusted prior to or during a procedure.
Also optionally, during active therapy (e.g., ablation) at least one near real-time MR lesion image (close-up view) generated using a pre-set scan plane(s) can be displayed to show tissue being treated (e.g., ablated) by the device in a window on a display at the workstation (block 325). This may be a high resolution image of the local tissue. Optionally, during the treatment, both an en face and side view of the local tissue (e.g., showing a lesion being formed in tissue) can be displayed (block 326).
Although described primarily herein with respect to cardiac EP procedures using ablation electrodes, other procedures and other ablation techniques can be used, such as, for example, cryogenic (e.g., cryoablation typically with an expandable balloon), laser, microwave, and even chemical ablation. In some embodiments, the ablation can be carried out using ultrasound energy. In particular embodiments, the ablation may be carried out using HIFU (High Intensity Focused Ultrasound). When MRI is used this is sometimes called Magnetic Resonance-guided Focused Ultrasound, often shortened to MRgFUS. This type of energy using a catheter to direct the energy to the target cardiac tissue can heat the tissue to cause necrosis. Similarly, the systems and/or components described herein can be useful for other MRI guided surgical intervention procedures, including, for example, delivering biologics or other drug therapies to target locations in tissue using MRI.
Some interventional tools may include an MRI receive antenna for improved SNR of local tissue. In some embodiments, the antenna has a focal length or signal-receiving length of between about 1-5 cm, and typically is configured to have a viewing length to receive MRI signals from local tissue of between about 1-2.5 cm. The MRI antenna can be formed as comprising a coaxial and/or triaxial antenna. However, other antenna configurations can be used, such as, for example, a whip antenna, a coil antenna, a loopless antenna, and/or a looped antenna. See, e.g., U.S. Pat. Nos. 5,699,801; 5,928,145; 6,263,229; 6,606,513; 6,628,980; 6,284,971; 6,675,033; and 6,701,176, the contents of which are hereby incorporated by reference as if recited in full herein. See also U.S. Patent Application Publication Nos. 2003/0050557; 2004/0046557; and 2003/0028095, the contents of which are also hereby incorporated by reference as if recited in full herein. Image data can also include image data obtained by a trans-esophageal antenna catheter during the procedure. See, e.g.,U.S. Pat. No. 6,408,202, the contents of which are hereby incorporated by reference as if recited in full herein.
As discussed above, embodiments of the present invention may take the form of an entirely software embodiment or an embodiment combining software and hardware aspects, all generally referred to herein as a “circuit” or “module.” Furthermore, the present invention may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium. Any suitable computer readable medium may be utilized including hard disks, CD-ROMs, optical storage devices, a transmission media such as those supporting the Internet or an intranet, or magnetic storage devices. Some circuits, modules or routines may be written in assembly language or even micro-code to enhance performance and/or memory usage. It will be further appreciated that the functionality of any or all of the program modules may also be implemented using discrete hardware components, one or more application specific integrated circuits (ASICs), or a programmed digital signal processor or microcontroller. Embodiments of the present invention are not limited to a particular programming language.
The present invention is described in part with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing some or all of the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowcharts and block diagrams of certain of the figures herein illustrate exemplary architecture, functionality, and operation of possible implementations of embodiments of the present invention. In this regard, each block in the flow charts or block diagrams represents a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order or two or more blocks may be combined, depending upon the functionality involved.
The workstation 60 and/or interface 44 may also include a decoupling/tuning circuit that allows the system to cooperate with an MRI scanner 10 and filters and the like. See, e.g., U.S. Pat. Nos. 6,701,176; 6,904,307 and U.S. Patent Application Publication No. 2003/0050557, the contents of which are hereby incorporated by reference as if recited in full herein.
In some embodiments, the intrabody device is configured to allow for safe MRI operation so as to reduce the likelihood of undesired deposition of current or voltage in tissue. The tool can include RF chokes such as a series of axially spaced apart Balun circuits or other suitable circuit configurations. See, e.g., U.S. Pat. No. 6,284,971, the contents of which are hereby incorporated by reference as if recited in full herein, for additional description of RF inhibiting coaxial cable that can inhibit RF induced current. The conductors connecting electrodes or other components on or in the catheter (or other interventional device) can also include a series of back and forth segments (e.g., the lead can turn on itself in a lengthwise direction a number of times along its length) and/or include high impedance circuits. See, e.g., U.S. patent application Ser. Nos. 11/417,594; 12/047,602; and 12/090,583, the contents of which are hereby incorporated by reference as if recited in full herein.
The intrabody devices 80 can be used and/or deliver desired cellular, biological, and/or drug therapeutics to a target area.
As shown in
As will be appreciated by those of skill in the art, the operating systems 449 may be any operating system suitable for use with a data processing system, such as OS/2, AIX, or zOS from International Business Machines Corporation, Armonk, N.Y., Windows CE, Windows NT, Windows95, Windows98, Windows2000, WindowsXP, Windows Visa, Windows7, Windows CE or other Windows versions from Microsoft Corporation, Redmond, Wash., Palm OS, Symbian OS, Cisco IOS, VxWorks, Unix or Linux, Mac OS from Apple Computer, LabView, or proprietary operating systems. For example, VxWorks which can run on the Scanner's sequence generator for precise control of pulse sequence waveform timings.
The I/O device drivers 458 typically include software routines accessed through the operating system 452 by the application programs 454 to communicate with devices such as I/O data port(s), data storage 456 and certain memory 414 components. The application programs 454 are illustrative of the programs that implement the various features of the data processing system and can include at least one application, which supports operations according to embodiments of the present invention. Finally, the data 456 represents the static and dynamic data used by the application programs 454, the operating system 449, the I/O device drivers 458, and other software programs that may reside in the memory 414.
While the present invention is illustrated, for example, with reference to the Modules 450-452 and/or 451, 452, 1450, 1452, being application programs, as will be appreciated by those of skill in the art, other configurations may also be utilized while still benefiting from the teachings of the present invention. For example, the Modulesand/or may also be incorporated into the operating system 449, the I/O device drivers 458 or other such logical division of the data processing system. Thus, the present invention should not be construed as limited to the configuration of
The I/O data port can be used to transfer information between the data processing system, the workstation, the MRI scanner, the ablation catheter and another computer system or a network (e.g., the Internet) or to other devices controlled by a processor. These components may be conventional components such as those used in many conventional data processing systems, which may be configured in accordance with the present invention to operate as described herein.
Non-Limiting Examples of Tissue Characterization Maps will be discussed below.
The thermal tissue characterization map can be based on thermal status at a given point in time or may be provided as a composite of heating of different tissue locations at different times (e.g., during and/or after ablation of different points at different times of the ablation procedure). The thermal map can be registered to a location of the internal ablation catheter (e.g., tip) at different times so that the location of the ablation catheter tip is correlated to the thermal activity/status at that location at that time as that is the time frame that the image data for that region illustrating increased thermal activity/heating is generated. That is, the image scan planes are taken to show the tissue at the location of the ablation catheter tip. The image scan planes are typically projected forward a known distance from the tracking coil so that the lesion tissue in front of the ablation tip is imaged.
The MR thermal data can be obtained using temperature imaging techniques (MR thermometry) to show temperature or phase variance. Examples of pulse sequences include, for example, SSFP and 2D GRE.
Tissue damage can be shown or detected using MR image data based on contrast agents such as those agents that attach to or are primarily retained in one of, but not both, healthy and unhealthy tissue, e.g., the contrast agent is taken up by, attaches to, or resides or stays in one more than in the other so that MR image data will visually indentify the differences (using pixel intensity). The contrast agent can be one or more of any known or future developed biocompatible agent, currently typically gadolinium, but may also include an antibody or derivative or component thereof that couples to an agent and selectively binds to an epitope present in one type of tissue but not the other (e.g., unhealthy tissue) so that the epitope is present in substantially amounts in one type but not the other. Alternatively, the epitope can be present in both types of tissue but is not susceptible to bind to one type by steric block effects.
The contrast based tissue characteristic maps can allow a clinician to assess both scar formation (isolation of the PV) and the volume of enhancement on a LA myocardial volume may indicate a poor outcome prediction and a clinician may decide to continue ablating.
Examples of pulse sequences that can be used for delayed hyper-enhancement MRI include, for example, gradient echo, SSFP (steady state free precession) such as TrueFISP on Siemens MRI Scanners, FIESTA on GE MRI Scanners, and b-FFE on Philips MRI Scanners.
In some embodiments, the system/circuit can employ interactive application of non-selective saturation to show the presence of a contrast agent in near real-time scanning. This option can help, for example, during image-guided catheter navigation to target tissue that borders scar regions. See, e.g., Dick et al., Real Time MRI enables targeted injection of labeled stem cells to the border of recent porcine myocardial infarction based on functional and tissue characteristics, Proc. Intl. Soc. Mag. Reson. Med. 11, p. 365 (2003); Guttman et al., Imaging of Myocardial Infarction for Diagnosis and Intervention Using Real-Time Interactive MRI Without ECG-Gating or Breath-Holding, Mag. Reson. Med, 52: 354-361 (2004), and Dick and Guttman et al., Magnetic Resonance Fluoroscopy Allows Targeted Delivery of Mesenchymal Stem Cells to Infarct Borders in Swine, Circulation, 2003; 108:2899-2904, which describe, inter alia, imaging techniques used to show regions of delayed enhancement in (near) real-time scans. The contents of these documents are hereby incorporated by reference as if recited in full herein.
After (and/or during) ablation, tissue will typically have edema. This can be detected in MRI using, for example, pulse sequences such as T2-weighted Turbo-Spin-Echo, HASTE (a Siemens term), SSFP, or T2-weighted gradient recalled echo (GRE).
Some tissue characteristic maps may show edema and thermal maps overlaid or otherwise combined as a composite map that can be used to evaluate a procedure. For example, to visually assess whether there is complete or incomplete scar formation to isolate pulmonary veins. It is believed that complete scar formation to isolate PV is associated with a better prognosis for AFIB.
MRI can be used to assess heart wall motion. Abnormal motion can be visually indicated on the tissue characterization map. Examples of pulse sequences that may be used to determine heart wall motion include, for example, DENSE, HARP and MR tagging.
While embodiments have been primarily discussed with respect to an MRI-guided cardiac systems, the systems can be used for other anatomical regions and/or deliver or apply other therapies and may also be used for diagnostic procedures. For example, the systems may be used for the esophagus and anatomy near the esophagus, e.g., the aorta, coronary arteries, mediastinum, the hepaticobiliary system or the pancreas in order to yield anatomic information about the structures in those areas, “pancreaticohepaticobiliary” structures (collectively the structures of the liver, gallbladder, bile ducts and pancreas), the tracheobronchopulmonary structure (structures including the lungs and the tracheobronchial tree), the nasopharynx system (e.g., a device introduced transnasally may be adapted for evaluating the arterial circle of Willis and related vascular structures for abnormalities, for example congenital or other aneurysms), the proximal aerodigestive system or the thyroid, the ear canal or the Eustachian tube, permitting anatomic assessment of abnormalities of the middle or inner ear, and further permitting evaluation of adjacent intracranial structures and lesions.
Embodiments of the systems and methods of the present invention may be particularly useful in those lesions whose extent is not readily diagnosed, such as basal cell carcinomas. These lesions may follow nerves into the orbit or into the intracranial area, extensions not evident with traditional imaging modalities to the surgeon undertaking the resection to provide real time information to the resecting surgeon or the surgeon performing a biopsy as to the likely areas of lymph node invasion.
It is also contemplated that the systems can be used in the “head and neck” which refers collectively to those structures of the ear, nose and throat and proximal aerodigestive system as described above, traditionally falling within the province of otorhinolaryngology. The term “head and neck,” as used herein, will further include those structures of the neck such as the thyroid, the parathyroid, the parotid and the cervical lymph nodes, and will include also the extracranial portions of the cranial nerves, including but not limited to the facial nerve, this latter nerve being included from its entry into the internal auditory meatus outward. The term “head and neck, as used herein, will also include those structures of the orbit or of the globe, including the oculomotor muscles and nerves, lacrimal glands and adnexal structures. As used herein, the term “head and neck” will further include those intracranial structures in proximity to the aforesaid head and neck structures. These intracranial structures may include, as examples, the pituitary gland, the pineal gland, the nuclei of various cranial nerves, the intracranial extensions of the cranial nerves, the cerebellopontine angle, the arterial circle of Willis and associated vascular structures, the dura, and the meninges.
In yet other embodiments, the systems can be used in the genourinary system, such as the urethra, prostate, bladder, cervix, uterus, and anatomies in proximity thereto. As used herein, the term “genitourinary” shall include those structures of the urinary tract, the male genital system and the female genital system. The urinary tract structures include the urethra, the bladder, the ureters, the kidney and related neural, vascular, lymphatic and adnexal structures. The male genital tract includes the prostate, the seminal vesicles, the testicles, the epididymis and related neural, vascular, lymphatic, ductal and adnexal structures. The female genital tract includes the vagina, the cervix, the non-gravid and gravid uterus, the fallopian tubes, the ovaries, the ova, the fertilized egg, the embryo and the fetus. The term “genitourinary” further refers to those pelvic structures that surround or support the abovementioned structures, such as the paraurethral tissues, the urogenital diaphragm or the musculature of the pelvic floor. The devices can be configured for transurethral placement for evaluation and treatment of female urinary incontinence or bleeding and may use high resolution images of the local tissue, e.g., different layers of the paraurethral tissues. It is understood, for example, that a clearly identified disruption in the muscle layers surrounding the urethra may be repaired surgically, but also can be guided by detailed anatomic information about the site of the abnormality. The devices may also be configured for placement in the genitourinary system such as into the ureter or renal pelvis, urinary tract, or transvaginal use in analysis of the vagina and anatomies in proximity thereto. For example, transvaginal or transcervical endouterine placement may be useful in the diagnosis of neoplasia, in the diagnosis and treatment of endometriosis and in the evaluation of infertility or diagnosis, treatment of pelvic disorders resulting in pelvic pain syndromes, evaluation/treatment of cervical and uterine malignancies and to determine their stages, obstetric use such as permitting anatomic evaluation of mother and fetus.
In another embodiment, the systems can be used for evaluating and/or treating the rectum or colon, typically by the transrectal route that can be inserted through the anus to a level within the rectum, sigmoid or descending colon where the designated anatomy can be visualized. For example, this approach may be used to delineate the anatomy of the prostate gland, and may further guide the biopsy or the extirpation of lesions undertaken transrectally or transurethrally.
In other embodiments, the systems and methods of the present invention may be used for the evaluation, diagnosis or treatment of a structure in the gastrointestinal system, or for the evaluation, diagnosis or treatment of a region of the gastrointestinal anatomy. As used herein, the term “gastrointestinal” shall include structures of the digestive system including the esophagus, the stomach, the duodenum, jejunum and ileum (small intestine), the appendix and the colon. The term “gastrointestinal anatomy” shall refer to the structures of the gastrointestinal system as well as the surrounding supporting structures such as the mesentery and the enclosing structures such as the peritoneum, the diaphragm and the retroperitoneum. Disorders of the gastrointestinal system are well-known in the medical arts, as are disorders of the gastrointestinal anatomy. In an exemplary embodiment, the intrabody device may be passed into the stomach.
In other embodiments, the systems and methods of the present invention may be used for the evaluation, diagnosis and treatment of the vascular system. The vascular system is understood to include the blood vessels of the body, both arterial and venous. The vascular system includes both normal and abnormal blood vessels, named and unnamed vessels, and neovascularization. Access to the vascular system takes place using techniques familiar to practitioners of ordinary skill in the art. The present invention may be used in blood vessels of all size and the intrabody devices may be dimensionally adapted to enter smaller caliber vessels, such as those comprising the distal coronary circulation, the intracranial circulation, the circulation of the distal extremities or the distal circulation of the abdominal viscera. According to these systems and methods, furthermore, positioning an intrabody device within the vascular system may be useful for evaluating, diagnosing and treating conditions in structures adjacent to or in proximity to the particular vessel within which the device is situated. Such structures are termed “perivascular structures.” As an example, a device placed within a coronary artery may provide information about the vessel itself and about the myocardium that is perfused by the vessel or that is adjacent to the vessel. A device thus positioned may be able to guide therapeutic interventions directed to the myocardial tissue, and may also be able to guide endovascular or extravascular manipulations directed to the vessel itself, It will be readily appreciated by those of ordinary skill in the art that a number of other applications exist or may be discovered with no more than routine experimentation using the systems and methods of the present invention within the vascular system,
It is understood that access to anatomic structures using the systems, devices modified to fit the intended purpose and anatomy, and methods of the present invention may be provided via naturally occurring anatomic orifices or lumens, as indicated in the examples above. It is further understood, however, that access to anatomic structures using these systems and methods may be additionally provided using temporary or permanent orifices that have been created medically,
Further, the methods and systems may cooperate with robotic driven systems rather than manual systems.
The aforesaid embodiments are understood to be exemplary only. Other embodiments wherein MRI probes may be used within body areas such as body canals, cavities, lumens, passageways, actual or potential spaces will be apparent to practitioners of ordinary skill in the relevant arts
In the drawings and specification, there have been disclosed embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims, Thus, the foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. In the claims, means-plus-function clauses, where used, are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.