Patent Publication Number: US-2013231557-A1

Title: Intracardiac echocardiography image reconstruction in combination with position tracking system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application and claims priority to and the benefit of U.S. patent application Ser. No. 12/060,714, filed Apr. 1, 2008, and entitled “INTRACARDIAC ECHOCARDIOGRAPHY IMAGE RECONSTRUCTION IN COMBINATION WITH POSITION TRACKING SYSTEM”, which claims the benefit of U.S. Provisional Application No. 60/938,442, filed on May 16, 2007, and entitled “4D INTRACARDIAC ECHOCARDIOGRAPHY RECONSTRUCTION WITH ASSISTANCE OF EM POSITION TRACKER” all of which are hereby incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND 
     The subject matter herein generally relates to medical imaging, and more specifically, to a system and method to navigate a tool through an imaged subject. 
     Image-guided surgery is a developing technology that generally provides a surgeon with a virtual roadmap into a patient&#39;s anatomy. This virtual roadmap allows the surgeon to reduce the size of entry or incision into the patient, which can minimize pain and trauma to the patient and result in shorter hospital stays. Examples of image-guided procedures include laparoscopic surgery, thoracoscopic surgery, endoscopic surgery, etc. Types of medical imaging systems, for example, computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), ultrasound (US), radiological machines, etc., can be useful in providing static image guiding assistance to medical procedures. The above-described imaging systems can provide two-dimensional or three-dimensional images that can be displayed to provide a surgeon or clinician with an illustrative map to guide a tool (e.g., a catheter) through an area of interest of a patient&#39;s body. 
     When performing a medical procedure, it is desired to calibrate or align the acquired image data of the imaged subject with the tracked tool so as to navigate through the imaged subject. Yet, the sensors to the track the tool and the detectors to acquire the image data may not be precisely located due to manufacturing variation. One example of application of image-guided surgery is to perform an intervention procedure to treat cardiac disorders or arrhythmias. Heart rhythm disorders or cardiac arrhythmias are a major cause of mortality and morbidity. Atrial fibrillation is one of the most common sustained cardiac arrhythmia encountered in clinical practice. Cardiac electrophysiology has evolved into a clinical tool to diagnose these cardiac arrhythmias. As will be appreciated, during electrophysiological studies, probes, such as catheters, are positioned inside the anatomy, such as the heart, and electrical recordings are made from the different chambers of the heart. 
     A certain conventional image-guided surgery technique used in interventional procedures includes inserting a probe, such as an imaging catheter, into a vein, such as the femoral vein. The catheter is operable to acquire image data to monitor or treat the patient. Precise guidance of the imaging catheter from the point of entry and through the vascular structure of the patient to a desired anatomical location is progressively becoming more important. Current techniques typically employ fluoroscopic imaging to monitor and guide the imaging catheter within the vascular structure of the patient. 
     BRIEF SUMMARY 
     A technical effect of the embodiments of the system and method described herein includes increasing the field of view of image data acquisition employed to generate three- or four-dimensional reconstruction of images to guide an interventional surgery procedure. In general, as a surgeon moves the medical instrument with respect to the patient&#39;s anatomy, virtual images of the instrument or object are displayed simultaneously relative to real-time acquired image data represented in the model of the patient&#39;s anatomy. Another technical effect of the system and method described herein of tracking includes readily tracking the spatial relationship of the medical instruments or objects traveling through an operating space of patient. Yet, another technical effect of the system and method described herein includes reducing manpower, expense, and time to perform interventional procedures, thereby reducing health risks associated with long-term exposure of the subject to radiation. 
     According to one embodiment, a system operable to generate a four-dimensional (4D) model of an imaged anatomy, the system comprising a controller and an imaging system including an imaging probe in communication with the controller. The 4D imaging probe is operable to acquire a real-time, 3D image data relative to a direction of image acquisition along an imaging plane. The system further includes a tracking system in communication with the controller. The tracking system includes at least one tracking element integrated with the 4D ultrasound imaging probe. The system is operable to process the real-time, 3D image data acquired by the imaging probe relative to generally real-time tracking information acquired by the tracking system to generate a 4D model of the imaged anatomy. 
     According to another embodiment, a method of image acquisition of an imaged anatomy is provided. The method comprises the steps of acquiring a series of partial view 3D image data with a 4D imaging probe defined by an image coordinate system and a time reference; tracking a position of the 4D imaging probe relative to the time reference and a tracking coordinate system; generating a 4D model of the imaged anatomy by merging the series of partial view 3D image data defined relative to the time reference; and displaying the 4D model in superposition with a representation of the tracked position of the imaging probe. 
     Systems and methods of varying scope are described herein. In addition to the aspects of the subject matter described in this summary, further aspects of the subject matter will become apparent by reference to the drawings and with reference to the detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic diagram of an embodiment of a system of the subject matter described herein to perform imaged guided medical procedures on an imaged subject. 
         FIG. 2  illustrates a picture of a tool to travel through the imaged subject. 
         FIG. 3  illustrates a more detailed schematic diagram of a tracking system in combination with an imaging system as part of the system described in  FIG. 1 . 
         FIG. 4  shows an embodiment of a method of performing an image-guided procedure via the system of  FIG. 1 . 
         FIG. 5  shows an embodiment of an illustration of tracking historical, current, and future locations of diagnostic or therapeutic catheters via the system of  FIG. 1  to form a surgical plan. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense. 
       FIG. 1  generally illustrates an embodiment of a system  100  operable to create a full-view three- or four-dimensional (3D or 4D) image or model from a series of generally real-time, acquired 3D or 4D image data (e.g., ultrasound) relative to tracked position information of an imaging probe (e.g., catheter  105 ) traveling through the imaged subject  110 . Although the following description is in regard to a catheter, the type of probe (e.g., endoscope, laparoscope, etc. or combination thereof) can vary. One embodiment of the system  100  is operable to acquire the series of 3D or 4D ultrasound image data while simultaneously rotating and tracking a position and orientation of the catheter  105  through the imaged subject. From the acquired 3D or 4D ultrasound image data, a technical effect of the system  100  includes creating an illustration of a full-view, 4D model of a region of interest (e.g., a beating heart) so as to guide delivery of an instrument. 
     An embodiment of the system  100  generally includes an image acquisition system  115 , a steering system  120 , a tracking system  125 , an ablation system  130 , and an electrophysiology system  132  (e.g., a cardiac monitor, respiratory monitor, pulse monitor, etc. or combination thereof), and a controller or workstation  134 . 
     Still referring to  FIG. 1 , the image acquisition system  115  is generally operable to generate a three-dimensional, or four-dimensional image model corresponding to an area of interest of the imaged subject  110 . Examples of the image acquisition system  115  can include, but are not limited to, computed tomography (CT), magnetic resonance imaging (MRI), x-ray or radiation, positron emission tomography (PET), ultrasound (US), angiographic, fluoroscopic, and the like or combination thereof. The image acquisition system  115  can be operable to generate static images acquired by static imaging detectors (e.g., CT systems, MRI systems, etc.) prior to a medical procedure, or real-time images acquired with real-time imaging detectors (e.g., angiographic systems, fluoroscopic systems, laparoscopic systems, endoscopic systems, etc.) during the medical procedure. Thus, the types of images acquired by the acquisition system  115  can be diagnostic or interventional. 
     An embodiment of the image acquisition system  115  includes a real-time, intracardiac echocardiography (ICE) imaging system  140  that employs ultrasound to acquire image data of the patient&#39;s anatomy and to merge acquired image data to generate a three-dimensional model of the patient&#39;s anatomy relative to time, generally herein referred to as a four-dimensional (4D) model or image. In accordance with another embodiment, the image acquisition system  115  is operable to fuse or combine acquired image data using above-described ICE imaging system  140  with pre-acquired or intra-operative image data or image models (e.g., two- or three-dimensional reconstructed image models) generated by another type of supplemental imaging system  142  (e.g., CT, MRI, PET, ultrasound, fluoroscopy, x-ray, etc. or combinations thereof). 
       FIG. 2  illustrates one embodiment of the catheter  105 , herein referred to as an ICE catheter  105 . The illustrated embodiment of the ICE catheter  105  includes a transducer array  150 , a micromotor  155 , a drive shaft or other mechanical connection  160  between the micromotor  155  and the transducer array  150 , an interconnect  165 , and a catheter housing  170 . 
     According to the illustrated embodiment in  FIG. 2 , the micromotor  155  via the drive shaft  160  generally rotates the transducer array  150 . The rotational motion of the transducer array  150  is controlled by a motor control  175  of the micromotor  155 . The interconnect  165  generally refers to, for example, cables and other connections coupling so as to receive and/or transmit signals between the transducer array  150  with the ICE imaging system (shown in  FIG. 1 )  105 . An embodiment of the interconnect  165  is configured to reduce its respective torque load on the transducer array  150  and the micromotor  155 . 
     An embodiment of the catheter housing  170  generally encloses the transducer array  150 , the micromotor  155 , the drive shaft  160 , and the interconnect  165 . The catheter housing  170  may further enclose the motor control  175  (illustrated in dashed line). The catheter housing is generally of a material, size, and shape adaptable to internal imaging applications and insertion into regions of interest of the imaged subject  110 . At least a portion of the catheter housing  170  that intersects the ultrasound imaging volume or scanning direction is comprised of acoustically transparent (e.g., low attenuation and scattering, acoustic impedance near that of the blood and tissue (Z-1.5M Rayl)) material. An embodiment of the space between the transducer array  150  and the housing  170  is filled with acoustic coupling fluid (e.g., water) having an acoustic impedance and sound velocity near those of blood and tissue (e.g., Z˜1.5M Rayl, V˜1540 m/sec). 
     An embodiment of the transducer array  150  is a 64-element one-dimensional array having 0.110 mm azimuth pitch, 2.5 mm elevation, and 6.5 MHz center frequency. The elements of the transducer array  150  are electronically phased in order to acquire a sector image generally parallel to a longitudinal axis  180  of the catheter housing  170 . In operation, the micromotor  155  mechanically rotates the transducer array  150  about the longitudinal axis  180 . The rotating transducer array  150  captures a plurality of two-dimensional images for transmission to the ICE imaging system  140  (shown in  FIG. 1 ). The ICE imaging system  140  (See  FIG. 1 ) is generally operable to assemble the sequence or succession of acquired 2D images so as to generally produce or generate 3D image or reconstructed models of the imaged subject  110 . 
     Still referring to  FIG. 2 , the motor control  175  via the micromotor  155  generally regulates or controls the rate of rotation of the transducer array  150  about the longitudinal axis  180  of the ICE catheter  105 . For example, the motor control  175  can instruct the micromotor  155  to rotate the transducer array  150  relatively slowly to produce the 3D reconstructed image or model. Also, the motor control  175  can instruct the micromotor  155  to rotate the transducer array  150  relatively faster to produce a real-time, 3D reconstructed image or model, referred to as the 4D reconstructed image or model. The 4D reconstructed image or model can be defined to include the 3D reconstructed image or model correlated relative to a general instant in time or instantaneous time. The motor control  175  is also generally operable to vary the direction of rotation so as to generally create an oscillatory motion of the transducer array  150 . By varying the direction of rotation, the motor control  175  is operable to reduce the torque load associated with the interconnect  165 , thereby enhancing the performance of the transducer array  150  to focus imaging on specific regions within the range of motion of the transducer array  150  about the longitudinal axis  180 . 
     Referring back to  FIG. 1 , an embodiment of the steering system  120  is generally coupled in communication to control maneuvering (including the position or the orientation) of the ICE catheter  105 . The embodiment of the system  100  can include synchronizing the steering system  120  with gated image acquisition by the ICE imaging system  140 . The steering system  120  may be provided with a manual catheter steering function or an automatic catheter steering function or combination thereof. With selection of the manual steering function, a user manually aligns an imaging plane vector  181  (See  FIG. 2 ) relative to a marker at the ICE catheter  105  shown on the 3D ICE reconstructed image or model, as well as directs the ICE catheter  105  to a target anatomical site. With selection of the automatic steering function, the controller  134  and/or steering system  120  or combination thereof estimates a displacement or a rotation angle  182  (See  FIG. 2 ) relative to a reference (e.g., see ICE imaging reference frame discussed later) that is needed to aim the ICE imaging plane vector  181  (See  FIG. 2 ) from the catheter  105 , passes position information of the ICE catheter  105  to the steering system  120 , and automatically drives or positions the ICE catheter  105  to continuously follow the delivery of a second instrument (e.g., an ablation catheter  184  of the ablation system  130 ). The reference can vary. 
     Referring to  FIGS. 1 and 3 , the tracking system  125  is generally operable to track or detect the position of the tool or ICE catheter  105  relative to the acquired image data or 3D or 4D reconstructed image or model generated by the image acquisition system  115 , or relative to delivery of a second instrument or tool (e.g., ablation system  130 , electrophysiology system  132 ). 
     As illustrated in  FIG. 3 , an embodiment of the tracking system  125  includes an array or series of microsensors or tracking elements  185 ,  190 ,  195 ,  200  connected (e.g., via a hard-wired or wireless connection) to communicate position data to the controller  134  (See  FIG. 1 ). Yet, it should be understood that the number of tracking elements  185 ,  190 ,  195 ,  200  can vary. An embodiment of the system  100  includes intraoperative tracking and guidance in the delivery of the at least one catheter  184  of the ablation system  130  by employing a hybrid electromagnetic and ultrasound positioning technique. The hybrid electromagnetic/ultrasound positioning technique facilitates dynamic tracking by locating tracking elements or dynamic references  185 ,  190 ,  195 ,  200 , alone or in combination with ultrasound markers  202  (e.g., comprised of metallic objects such brass balls, wire, etc.). The ultrasonic markers  202  may be active (e.g., illustrated in dashed line located at catheters  105  and  184 ) or passive targets (e.g., illustrated in dashed line at imaged anatomy of subject  110 ) (See  FIG. 1 ). An embodiment of the ultrasound markers  202  can be located at the ICE catheter  105  and/or ablation catheter  184  (See  FIG. 1 ) so as to be identified or detected in acquired image data by supplemental imaging system  142  and/or the ICE imaging system  140 . The tracking system  125  can be configured to selectively switch between tracking relative to electromagnetic tracking elements  185 ,  190 ,  195 ,  200  or ultrasound markers  202  or simultaneously track both. 
     For sake of example and referring to  FIG. 3 , assume the series of tracking elements  185 ,  190 ,  195 ,  200  includes a combination of transmitters or dynamic references  185  and  190  in communication or coupled (e.g., RF signal, optically, electromagnetically, etc.) with one or more receivers  195  and  200 . The number and type transmitters in combination with receivers can vary. Either the transmitters  185  and  190  or the receivers  195  and  200  can define the reference of the spatial relation of the tracking elements  185 ,  190 ,  195 ,  200  relative to one another. An embodiment of one of the receivers  195  represents a dynamic reference at the imaged anatomy of the subject  110 . An embodiment of the system  100  (See  FIG. 1 ) can be operable to register or calibrate the location (e.g., position and/or orientation) of the tracking elements  185 ,  190 ,  195 ,  200  relative to the acquired imaging data by the image acquisition system  115  (See  FIG. 1 ), and operable to generate a graphic representation suitable to visualize the location of the tracking elements  185 ,  190 ,  195 ,  200  relative to the acquired image data. 
     The tracking elements  185 ,  190 ,  195 ,  200  generally enable a surgeon to continually track the position and orientation of the catheters  105  or  184  (See  FIG. 1 ) during surgery. The tracking elements  185 ,  190 ,  195 ,  200  may be passively powered, powered by an external power source, or powered by an internal battery. One embodiment of one or more of the tracking elements or microsensors  185 ,  190 ,  195 ,  200  include electromagnetic (EM) field generators having microcoils operable to generate a magnetic field, and one or more of the tracking elements  185 ,  190 ,  195 ,  200  include an EM field sensor operable to detect an EM field. For example, assume tracking elements  185  and  190  include a EM field sensor operable such that when positioned into proximity within the EM field generated by the other tracking elements  195  or  200  is operable to calculate or measure the position and orientation of the tracking elements  195  or  200  in real-time (e.g., continuously), or vice versa, calculate the position and orientation of the tracking elements  185  or  190 . 
     For example, tracking elements  185  and  190  can include EM field generators attached to the subject  110  and operable to generate an EM field, and assume that tracking element  195  or  200  includes an EM sensor or array operable in combination with the EM generators  185  and  190  to generate tracking data of the tracking elements  185 ,  190  attached to the patient  110  relative to the microsensor  195  or  200  in real-time (e.g., continuously). According to one embodiment of the series of tracking elements  185 ,  190 ,  195 ,  200 , one is an EM field receiver and a remainder are EM field generators. The EM field receiver may include an array having at least one coil or at least one coil pair and electronics for digitizing magnetic field measurements detected by the receiver array. It should, however, be understood that according to alternate embodiments, the number and combination of EM field receivers and EM field generators can vary. 
     The field measurements generated or tracked by the tracking elements  185 ,  190 ,  195 ,  200  can be used to calculate the position and orientation of one another and attached instruments (e.g., catheters  105  or  184  (See  FIG. 1 )) according to any suitable method or technique. In one embodiment, the field measurements tracked by the combination of tracking elements  185 ,  190 ,  195 ,  200  can be digitized into signals for transmission (e.g., wireless, or wired) to the tracking system  125  or controller  134 . The controller  134  is generally operable to register the position and orientation information of the one or more tracking elements  185 ,  190 ,  195 ,  200  relative to the acquired imaging data from ICE imaging system  140  or other supplemental imaging system  142 . Thereby, the system  100  is operable to visualize or illustrate the location of the one or more tracking elements  185 ,  190 ,  195 ,  200  or attached catheters  105  or  184  (See  FIG. 1 ) relative to pre-acquired image data or real-time image data acquired by the image acquisition system  115  (See  FIG. 1 ). 
     Referring now to  FIGS. 2 and 3 , an embodiment of the tracking system  125  includes the tracking element  200  located at the ICE catheter  105 . The tracking element  200  is in communication with the receiver  195 . This embodiment of the tracking element  200  includes a transmitter that comprises a series of coils that define the orientation or alignment of the ICE catheter  105  about the rotational axis (generally aligned along the longitudinal axis  180 ) of the ICE catheter  105 . The tracking element  200  can be located integrally with the ICE catheter  105  and can be generally operable to generate or transmit a magnetic field  205  to be detected by the receiver  195  of the tracking system  125 . In response to passing through the magnetic field  205 , the receiver  195  generates a signal representative of a spatial relation and orientation of the receiver  195  or other reference relative to the transmitter  200 . Yet, it should be understood that the type or mode of coupling, link or communication (e.g., RF signal, infrared light, magnetic field, electrical potential, etc.) operable to measure the spatial relation varies. The spatial relation and orientation of the tracking element  200  is mechanically pre-defined or measured in relation relative to a feature (e.g., a tip) of the ICE catheter  105 . Thereby, the tracking system  125  is operable to track the position and orientation of the ICE catheter  105  navigating through the imaged subject  110 . 
     Alternatively, the tracking elements  185 ,  190 , or  200  can include a plurality of coils (e.g., Hemholtz coils) operable to generate a magnetic gradient field to be detected by the receiver  195  of the tracking system  125  and which defines an orientation of the ICE catheter  105 . An embodiment of the receiver  195  includes at least one conductive loop operable to generate an electric signal indicative of spatial relation and orientation relative to the magnetic field generated by the tracking elements  185 ,  190  and  200 . 
     Referring back to  FIG. 1 , an embodiment of the ablation system  130  includes the ablation catheter  184  that is operable to work in combination with the ICE catheter  105  of the ICE imaging system  140  to deliver ablation energy to ablate or end electrical activity of tissue of the imaged subject  110 . An embodiment of the ICE catheter  105  can include or be integrated with the ablation catheter  184  or be independent thereof. An embodiment of the ablation catheter  184  can include one of the tracking elements  185 ,  190  of the tracking system  125  described above to track or guide intra-operative delivery of ablation energy to the imaged subject  110 . Alternatively or in addition, the ablation catheter  184  can include ultrasound markers  202  operable to be detected from the acquired ultrasound image data generated by the ICE imaging system  140 . The ablation system  130  is generally operable to manage the ablation energy delivery to an ablation catheter  184  relative to the acquired image data and tracked position data. 
     Still referring to  FIG. 1 , an embodiment of an electrophysiological system(s)  132  is connected in communication with the ICE imaging system  140 , and is generally operable to track or monitor or acquire data of the cardiac cycle or respiratory cycle of imaged subject  110 . Data acquisition can be correlated to the gated acquisition or otherwise acquired image data, or correlated relative to generated 3D or 4D models created by the image acquisition system  115 . 
     An embodiment of the controller or workstation computer  134  can be generally connected in communication with and controls the image acquisition system  115  (e.g., the ICE imaging system  140  or supplemental imaging system  142 ), the steering system  120 , the tracking system  125 , the ablation system  130 , and the electrophysiology system  132  so as to enable each to be in synchronization with one another and to enable the data acquired therefrom to produce or generate a full-view 3D or 4D ICE model of the imaged anatomy. 
     An embodiment of the controller  134  includes a processor  220  in communication with a memory  225 . The processor  220  can be arranged independent of or integrated with the memory  225 . Although the processor  220  and memory  225  are described located at the controller  134 , it should be understood that the processor  220  or memory  225  or portion thereof can be located at the image acquisition system  115 , the steering system  120 , the tracking system  125 , the ablation system  130  or the electrophysiology system  132  or combination thereof. 
     The processor  220  is generally operable to execute the program instructions representative of acts or steps described herein and stored in the memory  225 . The processor  220  can also be capable of receiving input data or information or communicating output data. Examples of the processor  220  can include a central processing unit of a desktop computer, a microprocessor, a microcontroller, or programmable logic controller (PLC), or the like or combination thereof. 
     An embodiment of the memory  225  generally comprises one or more computer-readable media operable to store a plurality of computer-readable program instructions for execution by the processor  220 . The memory  225  can also be operable to store data generated or received by the controller  134 . By way of example, such media may comprise RAM, ROM, PROM, EPROM, EEPROM, Flash, CD-ROM, DVD, or other known computer-readable media or combinations thereof which can be used to carry or store desired program code in the form of instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a machine or remote computer, the remote computer properly views the connection as a computer-readable medium. Thus, any such a connection is properly termed a computer-readable medium. 
     As shown in  FIG. 1 , the controller  134  further includes or is in communication with an input device  230  and an output device  240 . The input device  230  can be generally operable to receive and communicate information or data from a user to the controller  210 . The input device  230  can include a mouse device, pointer, keyboard, touch screen, microphone, or other like device or combination thereof capable of receiving a user directive. The output device  240  is generally operable to illustrate output data for viewing by the user. An embodiment of the output device  240  can be operable to simultaneously illustrate or fuse static or real-time image data generated by the image acquisition system  115  (e.g., the ICE imaging system  140  or supplemental imaging system  142 ) with tracking data generated by the tracking system  125 . The output device  240  is capable of illustrating two-dimensional, three-dimensional, and/or four-dimensional image data or combinations thereof through shading, coloring, and/or the like. Examples of the output device  240  include a cathode ray monitor, a liquid crystal display (LCD) monitor, a touch-screen monitor, a plasma monitor, or the like or combination thereof. 
     Having provided a description of the general construction of the system  100 , the following is a description of a method  300  (see  FIG. 4 ) of operation of the system  100  in relation to the imaged subject  110 . Although an exemplary embodiment of the method  300  is discussed below, it should be understood that one or more acts or steps comprising the method  300  could be omitted or added. It should also be understood that one or more of the acts can be performed simultaneously or at least substantially simultaneously, and the sequence of the acts can vary. Furthermore, it is embodied that at least several of the following steps or acts can be represented as a series of computer-readable program instructions to be stored in the memory  225  of the controller  210  for execution by the processor  220  or one or more of the image acquisition system  115 , the steering system  120 , the tracking system  125 , or the ablation system  130  or the remote computer station connected thereto via a network (wireless or wired). 
     Referring now to  FIGS. 1 and 3  and for sake of example, assume that the spatial relation and orientation of the image data acquired by the transducer array  150  of the ICE imaging system  140  is defined by an image coordinate system  320  referenced in predetermined spatial relation and orientation relative to the transducer array  150  (See  FIG. 2 ) at the ICE catheter  105 . The image coordinate system  320  generally defines the spatial relation of voxels or pixels of image data relative to one another in the generated image frames or models generated by the ICE imaging system  140  in three-dimensions relative to time (i.e., four-dimensional model). Also, for sake of example, assume the tracking system  125  utilizes a tracking coordinate system  325  to define tracking spatial relation and orientation and movement of the tracking elements  185 ,  190 ,  195 , and  200  or respective catheters  105  and  184  relative to one another and to time. For example, the tracking coordinate system  325  references the orientation and spatial relation of the tracking element  200  at the ICE catheter  105  relative to one of the receiver or references  185 ,  190 ,  195  of the tracking system  125 . Also, for sake of example, assume the steering system  130  utilizes a mechanical or steering coordinate system  330  to define maneuvering and orientation of either or both of the catheters  105  and  184  relative to one another. The tracking system  125  may further employ an ultrasonic coordinate system  332  defined by ultrasonic markers  202 . Although these coordinate systems  320  and  325  and  330  can be described as Cartesian x-y-z coordinate systems, the type of coordinate systems  320 ,  325 ,  330 ,  332  (e.g., polar, etc.) can vary. In addition, the location and orientation of the coordinate systems  320 ,  325 ,  330 ,  332  can vary. 
     The controller  134  via the tracking system  125  is operable to track movement of the ICE catheter  105  in accordance with known mathematical algorithms programmed as program instructions of software for execution by the processor  220  of the controller  134  or by the tracking system  125 . An exemplary navigation software is INSTATRAK® as manufactured by the GENERAL ELECTRIC® Corporation, NAVIVISION® as manufactured by SIEMENS®, and BRAINLAB®. 
     Referring back to  FIG. 1 , having described registration of the ICE imaging system  140  with the tracking system  125 , the step of registering can further extend to registering the ICE imaging system  140  and tracking system  125  relative to other components of the system  100 , including the steering system  120 , ablation system  130 , or the electrophysiological system(s) (e.g., cardiac monitoring system, respiratory monitoring system, etc.)  132 , generally similar to the method of registering described above directed to the ICE imaging system  140  with the tracking system  125 . 
     Referring to  FIGS. 1 through 4 , the method  300  includes a step  335  of registering and/or calibrating the image acquisition system  115  (including the ICE imaging system  140 ), the steering system  120 , the tracking system  125 , and the ablation system  130  with one another. An embodiment of the step  335  of calibrating and registering includes registering both an ICE imaging reference frame or ICE imaging catheter coordinate system (referred to later as “ice”)  320  relative to the mechanical reference frame or coordinate system  330  of the steering system (referred to later as “mcs”)  130 , and additionally registering the previous coordinate systems  320 ,  330  relative to the electromagnetic microsensor or dynamic reference sensor frame or coordinate system (referred to later as “scs”)  325 . The above described registering events or coordinate transformations can be denoted as T(ice-&gt;scs) and T(mcs-&gt;scs), respectively. 
     An embodiment of the registering and/or calibrating step  335  includes the step of rigidly attaching at least one dynamic reference microsensor or tracking element  185 ,  190 ,  195  or  200  (See  FIG. 2 ) at the imaged anatomy. An example of this step includes integrating the dynamic reference microsensor at the distal end of a (steerable) catheter (e.g., dynamic reference catheter)  105  (See  FIG. 2 ), and delivering and anchoring the at least one dynamic reference tracking element  185 ,  190 ,  195 , or  200  (See  FIG. 2 ) at the imaged organ, e.g. the heart. According to another embodiment, the dynamic reference can be independent and separate of the catheter  105 . 
     The dynamic reference microsensor  185 ,  190 ,  195 , or  200  establishes a so-called world coordinate system (world reference frame—dynamic reference microsensor) (wcs)  340  (See  FIG. 3 ) that enables the system  100  to compensate for the respiratory and/or cardiac motion of the imaged organ in the display of the acquired generally real-time, 3D ultrasound image data or pre-operative or intra-operative image data acquired by the supplemental imaging system  142 . According to another example, the dynamic reference microsensor can be rigidly attached externally of the imaged subject  110 , e.g. the patient&#39;s chest such that the system  100  can compensate for motion of the imaged organ via synchronizing image acquisition relative to the respiratory and/or cardiac cycle of the imaged subject  110  tracked by the electrophysiology system  132 . The coordinate transformation from the tracking coordinate system  325  to the world coordinate system  340  can be denoted T(scs-&gt;wcs). 
     The embodiment of the method  300  further includes a step  345  of tracking (e.g., via the tracking system) a position or location of the at least one catheter  105  or  184  relative to the acquired image data. According to one embodiment of the method  300 , at least one instrument catheter  105  or  184  is integrated with a plurality of hybrid electromagnetic position microsensors  185 ,  190 ,  195 ,  200  and ultrasonic markers  202 . The electromagnetic microsensors  185 ,  190 ,  195 ,  200  and ultrasonic markers  202  can both be located and rigidly mounted on the at least one instrument catheter  105  or  184 . A computer image-processing program is operable to detect and mark positions of the ultrasonic markers  202  relative to the generated 3D or 4D ICE image model. 
     The controller  134  can be generally operable to align positions of the ultrasonic markers  202  with the tracking coordinate reference frame or coordinate system  325 . This registration information may be used for the alignment (calibration) between the tracking reference frame or coordinate system  325  and the ultrasonic marker reference frame or coordinate system  332  relative to the ICE imaging reference frame or coordinate system  320 . This information may also be used for detecting the presence of electromagnetic distortion or tracking inaccuracy. 
     An embodiment of the method  300  further includes a step  355  of acquiring image data (e.g., scan) of the anatomy of interest of the imaged subject  110 . An embodiment of the step of acquiring image data includes generating a series of partial-views  358  of 3D or 4D image data from real-time image data acquired while rotating the ICE catheter  105  around the longitudinal axis  180  (See  FIG. 2 ) that extends through the center of the ICE catheter  105 . Image acquisition with the catheter  105  can include more general motion in addition to rotation of the transducer array  150  about axis  180 . The motor  155  can provide some range of rotation of the transducer array  150  to generate a 4D model  112  with an enhanced field of view. To image an entire “anatomy of interest” (e.g. an entire chamber of the heart), the imaging catheter  105  can be deflected, advanced, or retracted in addition to rotation of the transducer array  150 . 
     deflect, advance, or retract the catheter, in addition to simple rotation. 
     An embodiment of the image acquisition step  355  includes calculating positions or degree of rotation of the ICE catheter  105  about the longitudinal axis  180 . The image acquisition step  355  can further include synchronizing or gating a sequence of image acquisition relative to tracking data acquired by the hybrid tracking system  125  (e.g., tracking a location (e.g., position and/or orientation) relative to the acquired image data). In addition, the image acquisition step  355  can further include synchronizing or gating a sequence of image acquisition relative to measuring cardiac and respiratory signals by the electrophysiology system  132 . 
     According to one embodiment of the image acquisition step  355 , the ablation catheter  184  can be detected or is visible in the acquired image data by the ICE imaging system  140 . By “scribbling” the anatomical surface of the anatomy of interest with the at least one instrument catheter  184  relative to acquired tracking data of the location of the catheters  105  or  184 , the anatomical boundary may be enhanced to result in a more accurate surface model for image registration and surgical planning. 
     Referring to  FIGS. 1 through 4 , an embodiment of the method  300  further includes a step  360  of generating or reconstructing a full-view 3D or 4D model  362  from the sequence of generated partial-view 3D or 4D image views  358  relative to the world coordinate frame  340  established by the dynamic reference or tracking element  185 ,  190 ,  195 , or  200 . The 4D ICE imaging system  140 , the tracking system  125 , the steering system  120 , the cardiac and respiratory monitoring system  132 , and the 4D ICE imaging catheter  105  are generally involved in acquisition and reconstructing the full view 4D ICE model for the anatomy of the imaged subject  110 . The step  360  can include merging the series of partial 3D or 4D image views or views  358  (See  FIG. 3 ) relative to acquired electrophysiology data (e.g., cardiac cycle, respiratory cycle) acquired by the electrophysiology system  132 . The step  360  can further include generating a display of the generated 3D or 4D model  362  (See  FIG. 3 ) synchronized relative to electrophysiology signals  364 ,  366  (see  FIG. 1 ). 
     An embodiment of the method  300  can further include a step  370  of acquiring or measuring location data of the ultrasonic markers  202  described above by detecting or identifying the voxels illustrative thereof in the acquired, real-time 3D or 4D ultrasound image data via the ICE imaging system  140 . An embodiment of the ultrasonic markers  202  can be configured to identify each of a series of tools or catheters  105  or  184  delivered through an imaged subject  110 . An embodiment of the pattern of the tracking elements  185 ,  190 ,  195 ,  200  and/or ultrasonic markers  202  may be uniquely defined for different types of instrument catheters  105  or  184  for identification purposes. Dependent on the uniquely defined tracking elements  185 ,  190 ,  195 ,  200  and/or ultrasonic markers  202 , the image acquisition system  115 , tracking system  125  or controller  134  or combination thereof can be operable to uniquely identify location and orientation of each of the tools or catheters  105  and  184 . An embodiment of the system  100  is operable to extract the location of voxels from the acquired image data correlated to the imaging of the ultrasonic markers  202 . In this way, the location of the ultrasonic markers  202  may be tracked with respect to the ICE catheter  105  or ablation catheter  184 , or vice versa. 
     An embodiment of the system  100  includes a software having image processing programs operable to extract the locations of the ultrasonic markers  202  from the acquired generally real-time, 3D or 4D ultrasound image data (e.g., partial views  358 ), an electromagnetic distortion detection program using information from the 3D or 4D ultrasound image data, and the tracking program with instructions to execute steps of the hybrid tracking technique described above. According to one embodiment, the system  100  processes acquired 3D or 4D ICE image data to extract voxel positions of the ultrasonic markers  202  relative to the ablation catheter  184 . The system  100  also processes the acquired 3D or 4D ultrasound image data to generate a surface model of the imaged anatomy. The system  100  is also operable to calculate the vector  181  generally representative of a central direction of a field of view of the ICE imaging system  140 . 
     Referring to  FIGS. 1 through 5 , according to another embodiment, the system  100  includes a graphic user interface (GUI)  371  operable to facilitate image data acquisition and reconstruction of the 3D or 4D ICE model  362 , including display of a generally real-time 3D or 4D ICE image model  362  created from the acquired anatomical data; to display detected/identified locations or representations thereof of at least one instrument catheter  105  or  184  relative to the illustrated, real-time 3D or 4D ICE image model  362 ; to display the vector  181  showing the general central direction of a field of view of the 3D or 4D ICE image model  362 ; to receive an input of a selection of a target anatomical site relative to the 3D or 4D ICE image model  362 ; to display a distance between the tip of the catheter  105  or  184  relative to an anatomical surface of the 3D or 4D ICE image model  362 ; to display a path of delivery of the catheter  105  or  184  relative to a target anatomical site illustrated at the 3D or 4D ICE image model  362 ; to display synchronization of image data acquisition to create the 3D or 4D ICE image model  362  relative to the signal of the tracked cardiac or respiratory cycle; and to receive input indicative of a selection between a manual and automatic steering function of the ICE catheter  105 . 
     According to one embodiment, the system  100  automatically conducts a 4D scan of the anatomy of interest of the imaged subject  110 . The controller  134  can calculate or estimate a number of the ICE scans needed to generate the full-view 4D model reconstruction. Based on the field of view (FOV) of the ultrasound transducer array  150  and a tracked starting position of the ICE catheter  105 , the system  100  is operable to calculate a set of orientations (e.g. T(mcs.p1-&gt;scs)T(scs-&gt;wcs), T(mcs.p2-&gt;scs)T(scs-&gt;wcs), T(mcs.pn-&gt;scs)T(scs-&gt;wcs) where p1, p2, and pn are different catheter orientations) of the ultrasound imaging plane  181  to conduct a full-view 4D scan in the dynamic reference sensor frame  340 . The controller  134  can also communicate signals representative of instructions to the steering system  130  that direct automatic maneuvering and rotating of the ICE catheter  105  to a series of imaging positions, e.g., T(mcs.p1-&gt;scs)T(scs-&gt;wcs), T(mcs.p2-&gt;scs)T(scs-&gt;wcs), . . . , and T(mcs.pn-&gt;scs)T(scs-&gt;wcs). 
     According to another embodiment, the ICE catheter  105  of the ICE imaging system  140  executes the full-view 3D or 4D ICE scan of the imaged anatomy according to received input instructions directed to manually drive the ICE catheter  105  into a series of imaging positions, as well as received input instructions directed to manually activate each event of image acquisition. Referring to  FIG. 5 , an embodiment of the GUI  371  facilitates the 3D or 4D ICE image acquisition via displaying representations  372  of a history of each position of the ICE catheter  105  or ablation catheter  184  at events of image acquisition, displaying a representation  373  of a current position of the ICE catheter  105 , and displaying a representation  374  of a next or future position or location of an image acquisition event by the ICE catheter  105 . 
     The 3D or 4D ICE image and catheter position acquisitions can be triggered at the preset cardiac and respiratory phase, e.g. t1, t2, . . . , tn. At a given catheter orientation (pi), the system  100  is operable to acquire and transform a series of ultrasound images relative to the world coordinate frame  340 , represented by [T(ice.pi-&gt;scs)T(scs-&gt;wcs)].t1, [T(ice.pi-&gt;scs)T(scs-&gt;wcs)].t2, . . . , and [T(mcs.pi-&gt;scs)T(ice-&gt;wcs)].tn. 
     Alternatively, the 3D or 4D ICE image acquisition may be conducted at a dynamic or variable rate optimized according to the imaged volume, desired ultrasound image quality, etc. With each acquired ultrasound image volume (or plane or beam), the system  100  records a current cardiac and respiratory phase (ti), and the current catheter or image position (pi). 
     Upon the completion of the full-view 3D or 4D scan, the system  100  can reconstruct the generated series of partial views  358  of 3D or 4D ultrasound image data at different catheter orientations and different cardiac cycle time or phase. By transforming or registering the partial views  358  of the acquired 3D or 4D ICE image data relative to the world coordinate frame  340  (see  FIG. 3 ), the system  100  can calculate the following transformations: [T(ice.p1-&gt;scs)T(scs-&gt;wcs)].t1, [T(ice.p1-&gt;scs)T(scs-&gt;wcs)].t2, . . . , [T(ice.p2-&gt;scs)T(scs-&gt;wcs)].t1, . . . , and [T(ice.pn-&gt;scs)T(scs-&gt;wcs)].tn. 
     To generate the full-view 3D or 4D ICE model  362 , an embodiment of the system  100  can group the partial views  358  of 3D or 4D ultrasound image data according the cardiac timing sequence, e.g. [T(ice.p1-&gt;scs)T(scs-&gt;wcs)].t1, [T(ice.p2-&gt;scs)T(scs-&gt;wcs)].t1, . . . , and [T(ice.pn-&gt;scs)T(scs-&gt;wcs)].t1 at cardiac phase t1. A number of image processing techniques such as image smoothing, filtering, or averaging can be used to merge the series of partial views  358  to a full-view 3D or 4D ICE model  362  [T(ice.3D-&gt;wcs)].t1 for the t1 cardiac phase or the respiratory phase. 
     The controller  134  is operable to repeat the above-described image reconstruction process to create a full-view 3D or 4D ICE model of the anatomic structure, denoted as [T(ice.3D-&gt;wcs)].t1, [T(ice.3D-&gt;wcs)].t2, . . . , and [T(ice.3D-&gt;wcs)].tn, for the rest of the cardiac phases or respiratory phases. 
     According to one embodiment of the system  100  and method  300  described herein, the controller  134  can control operation of the steering system  120 , the tracking system  125 , the ablation system  130 , and the electrophysiology monitoring system  132 , the ICE imaging system  140  and/or any supplemental imaging system  142 . Via the controller  134 , the system  100  is operable to process the acquired image data relative to the acquired real-time tracking information from the hybrid tracking system  125  and the cardiac and respiratory cycle information from the electrophysiology system  132 . The system  100  is further operable to generate full-view 3D or 4D ICE model of the imaged anatomy, register the acquired partial views  358  of the real-time 3D or 4D ICE image data with the generated full-view 3D or 4D model  362  or other pre-operative or intra-operative real-time non-ICE images  375  (e.g., MRI, CT, PET, etc.), and control the steering system  120  in maneuvering the ICE catheter  105  or ablation catheter  184  relative to the direction of the 3D or 4D ICE imaging plane  181  (or vice versa) (See  FIG. 2 ). 
     Referring to  FIGS. 1 through 5 , the method  300  further includes a step  380  of generating a display  385  of the partial views  358  (See  FIG. 3 ) of the general real-time 3D or 4D ICE image data superimposed or combined relative to one or more of the following: the full-view 4D ICE model  362  (See  FIG. 3 ); one or more of an MRI, CT, PET, or other pre- or intra-operative images  375 ; representations  372 ,  373 ,  374  (See  FIG. 5 ) of the generally real-time tracked positions of the ICE catheter  105  or therapy catheter  184  (See  FIG. 1 ); the cardiac and/or respiratory cycle data  364 ,  366  (See  FIG. 1 ) synchronized with a time of acquisition of the partial views  358  of the 3D or 4D ICE image data and positions of either catheter  105  or  184 ; a preoperative surgical plan, including identifying and illustrating the surgical or ablation targets according to preoperative or intraoperative images  375  (e.g., EP information superimposed on the full-view 3D or 4D model  362 ) (See  FIG. 3 ); selection between manual and automatic catheter steering functions; and generating a display of the one or more locations of the surgical site on the full-view 3D or 4D ICE model  362  during delivery of the surgical treatment. 
     A technical effect of the embodiments of the system  100  and method  300  described above is to provide an image reconstruction algorithm that provides a full-view 4D image model of anatomic structure, fast registration of the acquired partial views  358  of the 3D or 4D ICE image data relative to other preoperative and intraoperative images  375 , capability to create the surgical plan that comprises graphic representations of historical locations, current locations, and future locations of image acquisition  372 ,  373 ,  374  (See  FIG. 5 ), and intra-operative guidance to maneuver various devices, for example the diagnostic or therapeutic catheters  105  or  184 . The system  100  and method  300  also provide an integrated solution to create a full-view 3D or 4D ICE model  362  from the series of real-time partial 3D or 4D views  358  and catheter position information. 
     Another technical effect of the above-described system  100  and method  300  described above is an ability to register the 3D or 4D ICE imaging system  140  with the tracking system  125  or another type or supplemental imaging system  142  via execution of computer-readable program instructions stored and executable at the controller  134 . As described above, the controller  134  is operable to perform registration of the coordinate systems  320 ,  325 ,  330 ,  332 ,  340  relative to one another. 
     Another technical effect of the system  100  and method  300  described above is an ability to combine image data and models generated by the ICE imaging system  140  with a location of the ICE catheter  105  or ablation catheter  184  being tracked by tracking system  125 , all in combination with imaged data or models generated by another imaging system  142 , with an ability to compensate for deficiencies in the imaged data acquired with the ICE imaging system  140 . Accordingly, the system  100  and method  300  enhance tracking and guidance of the position and orientation of the catheter  105  or transducer array  150  navigating through the imaged subject  110 . The system  100  and method  300  also synchronize tracking and guidance of movement and orientation of the ICE catheter  105  or ablation catheter  184  associated with the ablation system  130 , with each other as well as with electrophysiological signals (e.g., respiratory cycle, cardiac cycle, etc.) as tracked by the electrophysiological system(s)  132 . 
     Technical effects of integrating the 4D ICE imaging system  140  with the tracking system  125  includes, inter alia, enhancement of the field of the view of the 4D ICE imaging catheter  105 , acceleration of the 4D ICE registration process with other pre-operative and intra-operative images, and enhancement of pre-operative surgical planning and intraoperative instrument catheter guidance. 
     Embodiments of the subject matter described herein include method steps which can be implemented in one embodiment by a program product including machine-executable instructions, such as program code, for example in the form of program modules executed by machines in networked environments. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Machine-executable instructions, associated data structures, and program modules represent examples of computer program code for executing steps of the methods disclosed herein. The particular sequence of such computer- or processor-executable instructions or associated data structures represent examples of corresponding acts for implementing the functions described in such steps. 
     Embodiments of the subject matter described herein may be practiced in a networked environment using logical connections to one or more remote computers having processors. Logical connections may include a local area network (LAN) and a wide area network (WAN) that are presented here by way of example and not limitation. Such networking environments are commonplace in office-wide or enterprise-wide computer networks, intranets and the Internet and may use a wide variety of different communication protocols. Those skilled in the art will appreciate that such network computing environments will typically encompass many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Embodiments of the subject matter described herein may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination of hardwired or wireless links) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
     This written description uses examples to disclose the subject matter, including the best mode, and also to enable any person skilled in the art to make and use the subject matter described herein. Accordingly, the foregoing description has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the subject matter to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the subject matter described herein. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.