Source: https://patents.google.com/patent/JP5866136B2/en
Timestamp: 2019-12-14 21:03:19
Document Index: 796313278

Matched Legal Cases: ['art 10', 'art 10', 'art 10', 'art 10', 'art 10', 'art 10', 'art 10']

JP5866136B2 - System and method for local non-rigid registration of a catheter guide system to image data or models - Google Patents
System and method for local non-rigid registration of a catheter guide system to image data or models Download PDF
JP5866136B2
JP5866136B2 JP2009552798A JP2009552798A JP5866136B2 JP 5866136 B2 JP5866136 B2 JP 5866136B2 JP 2009552798 A JP2009552798 A JP 2009552798A JP 2009552798 A JP2009552798 A JP 2009552798A JP 5866136 B2 JP5866136 B2 JP 5866136B2
JP2009552798A
JP2010520784A (en
JP2010520784A5 (en
エリック エス． オルソン
エリック ジェー． ボス
ジェフリー エイ． シュワイツァー
2007-03-09 Priority to US11/715,923 priority Critical
2007-03-09 Priority to US11/715,923 priority patent/US10433929B2/en
2008-02-26 Application filed by セント・ジュード・メディカル・エイトリアル・フィブリレーション・ディヴィジョン・インコーポレーテッド filed Critical セント・ジュード・メディカル・エイトリアル・フィブリレーション・ディヴィジョン・インコーポレーテッド
2008-02-26 Priority to PCT/US2008/054969 priority patent/WO2008112420A2/en
2010-06-17 Publication of JP2010520784A publication Critical patent/JP2010520784A/en
2011-03-31 Publication of JP2010520784A5 publication Critical patent/JP2010520784A5/en
2016-02-17 Publication of JP5866136B2 publication Critical patent/JP5866136B2/en
This application claims priority from US application Ser. No. 11 / 715,923, filed Mar. 9, 2007. This application is also related to US application Ser. No. 11 / 715,919, filed on Mar. 9, 2007. All of these applications are hereby incorporated by reference.
The present invention relates to a localization system used for cardiac diagnosis and therapeutic treatment. In particular, the present invention relates to a system and method for integrating a localization system coordinate system into an externally created model or image data set coordinate system.
It is known to generate heart chamber geometries in preparation for cardiac diagnostic or therapeutic procedures. Often, to capture multiple reference points, a mapping catheter is introduced into the target heart chamber, in which it is irregularly, pseudo-randomly, or one or more It is moved according to a predetermined pattern. The three-dimensional coordinate values of the mapping catheter are typically measured using a localization system (sometimes referred to as a mapping system, a guidance system, or a position feedback system). The localization system measures the coordinate values of the mapping catheter in the localization field. Typically, the coordinate values in the localization field of the mapping catheter are measured, for example by associating a characteristic value of the localization field, such as the voltage acting on the mapping catheter, with the position of the catheter in the field. The surface surrounding the multiple reference points creates a surface model for the heart chamber geometry.
In some aspects, it is preferable to combine a localization system model for the heart chamber shape with an external image or segmented model for the heart chamber. For example, it is known to use CT or magnetic resonance images of a patient's heart to assist a cardiac specialist or other medical personnel in performing electrophysiological analysis or partial cardiac resection procedures. Yes. These three-dimensional images of the heart help medical personnel visually identify where medical devices, such as ablation catheters, are within the patient's heart and increase the effectiveness of the procedure. Moreover, such a three-dimensional image advantageously provides further details regarding the shape of the heart chamber that cannot be obtained from a model created solely by the localization system.
The localization system is also used to detect the position of other objects, such as electrophysiology or ablation catheters, within the localization field. It may be preferable to describe the position of the object measured by the localization system on a three-dimensional image. However, 3D images usually do not use the same coordinate system as that of the localization system. Therefore, the position of the object measured by the localization system cannot be directly displayed on the three-dimensional image. Furthermore, when the affine transformation is adopted to convert the position of the object measured by the localization system into the position on the three-dimensional image, the nonlinearity and non-uniformity of the localization field may cause an error.
Preferably, an external three-dimensional model for the heart geometry can be integrated into the catheter guidance system.
Furthermore, it is preferable to be able to provide a conversion technique for accurately converting the measurement value obtained by the catheter guidance system into a position in the external model.
Furthermore, the conversion technique preferably reflects the non-linearity and non-uniformity of the catheter guidance system.
In the following, a method is disclosed for integrating a catheter guidance system, for example an electric field localization system or a magnetic field localization system, into a three-dimensional image. The method comprises the following steps.
(A) Acquire a three-dimensional image of at least a part of the heart. The three-dimensional image includes position information of a plurality of reference points located on the surface of the heart.
The (b) tools placed on a first surface position X 1 on the surface of the heart.
(C) measuring a first positional information of the surface position X 1.
And (d) identifying a first location information of the position Y 1 corresponding in a three-dimensional image.
(E) and the position information X 1 of the first surface position measured by the catheter guidance system, a combination of positional information Y 1 of the first position on the three-dimensional image, making reference pair (X 1, Y 1).
(F) In each reference pair (X i , Y i ), the position in the catheter guidance system is determined in the three-dimensional image by using at least one reference pair so as to measure a displacement error with an error function of approximately zero. Create a mapping function that converts to a position.
A 3D image can be a CT image, a magnetic resonance image, an ultrasound image, an X-ray image, a fluoroscopic image, an image template, an image created by a localization system, any of the above-mentioned segmented models, or any of the above It may be selected from a combination.
In some embodiments of the present invention, the step of identifying a first position Y 1 correspondence on the three-dimensional image, and displaying the shape of the three-dimensional image on a display device, the displayed three-dimensional image it includes identifying the corresponding first position Y 1 by using the input device on the shape. Position information X 1 of the first surface position measured by the catheter guidance system is automatically associated with the position information Y 1 of the corresponding first position, as a reference pair (X 1, Y 1). Although at least three reference pairs are created, in some embodiments, four reference pairs are created.
A thin plate splines algorithm may be used to generate the mapping function. Typically, the thin plate spline algorithm involves summing a fixed value of a plurality of weighted basis functions. The number of basis functions weighted here is equal to the number of reference pairs created. If necessary, the resulting mapping function may be smoothed using a regularization parameter, which is preferably approximately zero. Alternatively, a mean value coordinate algorithm can be used to generate the mapping function. In still other embodiments, a radial basis function networks algorithm can be used to generate the mapping function. Advantageously, the algorithm utilized can compensate for catheter guide system non-uniformities and in each reference pair, the mapping error can be approximately zero.
Although not essential, at least one reference pair may be smoothed prior to generating a mapping function using the reference pair. At least one reference pair can be smoothed with a kernel smoothing function. Alternatively, the reference pair can be smoothed by a technique including the following steps. This technique uses the reference pair to calculate a rigid body alignment that produces an error vector between the members of at least one reference pair, and derives from the rigid body alignment Redefining the reference pair such that the elements of the reference pair move in an approaching direction along the error vector, and generating a mapping function from the at least one reference pair thus redefined.
Further disclosed is a method for integrating a catheter guidance system into an n-dimensional image of a part of a patient's body. The method is
(A) Obtain an n-dimensional image of a part of the patient's body. The n-dimensional image includes position information of a plurality of reference points located on the surface of a part of the body.
(B) Place the tool at surface position X on the surface of a part of the body.
(C) The position information of the surface position X is measured.
(D) The position information of the corresponding position Y in the n-dimensional image is specified.
(E) A reference pair (X, Y) is created by combining the position information of the measured surface position X and the position information of the corresponding position Y on the n-dimensional image.
(F) Repeat steps (b) to (e) to create a plurality of reference pairs (X i , Y i ).
(G) Create a function f that maps a point in the n-dimensional space of the catheter guidance system to the n-dimensional space of the n-dimensional image. Here, for each of the plurality of reference pairs, a function f is created in which f (X i ) −Y i is substantially zero. The function f is generated by a thin plate spline algorithm, an average coordinate value algorithm, a radial basis function network algorithm, or other suitable warping algorithm.
In another aspect of the present invention, a method for integrating a catheter guidance system into an image that includes at least a portion of a heart determines the position information for an n-dimensional space in the catheter guidance system at position X: The position information of the corresponding position Y with respect to the n-dimensional space in at least a part of the image is determined, the position information of the position X and the position information of the corresponding position Y are combined as a reference pair, and the point in the catheter guidance system is the point in the image Each step of generating a mapping function f to be converted into In the above, a function f is obtained in which the difference between f (X) and Y is almost zero in each reference pair.
The step of determining position information for the catheter guide system at position X comprises the following steps: a model of at least a part of the heart, which is located on the surface of the heart being measured with respect to the catheter guide system. A model including the position information of the reference point of the image is obtained, the shape of at least a part of the model of the heart is displayed on the display device, and the position X on the shape of the model of the at least part of the heart is displayed using the input device. Each step of specifying and determining position information of the position X specified on the shape of at least a part of the model of the heart may be included. Similarly, determining the position information for at least a portion of the image of the heart at the corresponding position Y includes the following steps: an image of at least a portion of the heart being measured relative to the image. An image including position information of a plurality of reference points located on the surface of the heart is acquired, the shape of the image of at least a part of the heart is displayed, and the shape of the image of at least a part of the heart is displayed using the input device The method may include the steps of specifying the position Y and determining position information of the position Y specified on the shape of the image of at least a part of the heart. In the above, the position X specified on the shape of the model of at least a part of the heart and the position Y specified on the shape of the image of at least part of the heart correspond to a common point on the surface of the heart. Yes.
In place of the above, determining the position information for the catheter guidance system at position X includes:
The catheter may be placed at the position X, and the position information of the position X may be measured by the catheter guidance system. The catheter guide system may measure position information of the position X based on at least one characteristic value of the electric field at the position X or at least one characteristic value of the magnetic field at the position X.
In accordance with another embodiment of the present invention, a system for integrating a catheter guidance system into an image of at least a portion of the heart comprises the following arrangement: a catheter inserted into at least a portion of the heart, and the catheter is inserted into the heart. A catheter guidance system for positioning at position X located on at least a surface and measuring position information of position X located on at least a surface of the heart, and an image of at least a portion of the heart An image including position information of a plurality of reference points located on the surface of at least a part of the heart, and a position Y (position on the image) coupled to the image of at least a part of the heart Y is a position on the surface of at least part of the heart and corresponds to position X where the catheter is placed) The reference device (X, Y) combines the position information measured for the position X, which is located on the surface of at least a part of the heart where the catheter is placed, and the position information of the selected position Y. And a conversion process programmed to generate a mapping function f that converts a position in the n-dimensional space in the catheter guidance system to a position in the n-dimensional space in the image. Equipment. The conversion processing device generates a mapping function in which the difference between f (X) and Y is almost zero in each reference pair (X, Y). The transformation processor may be programmed with a thin plate spline algorithm, an average coordinate value algorithm, a radial basis function network algorithm, or other suitable distortion algorithm.
In yet another embodiment of the invention, a system for integrating a catheter guide system into an image of at least a portion of the heart is an image of at least a portion of the heart and is located on a surface of at least a portion of the heart. An image including n-dimensional position information of a plurality of reference points, and a model of at least a part of the heart, the plurality of reference points located on the surface of at least a part of the heart and a catheter A model including n-dimensional position information of a plurality of reference points measured with respect to the guidance system, and a user selects a position Y on an image of at least a portion of the heart and at least a portion of the heart An input device for selecting a position X on a model of the heart and a position Y selected on an image of at least a part of the heart A combination processor programmed to combine position information and position information of a selected position X on at least a part of the model of the heart to form a reference pair (X, Y); and position in the catheter guidance system And a conversion processor programmed to generate a mapping function f that converts the image to a position in the image. The conversion processing device generates a mapping function f in which the difference between f (X) and Y is almost zero in each reference pair (X, Y). In the above, the position Y specified on the image of at least a part of the heart and the position X specified on the model of at least a part of the heart are the common points located on the surface of at least a part of the heart It is preferable that
An advantage of the present invention is that the catheter guidance system can be integrated into an external model, and the measurement values obtained by the catheter guidance system are given a meaning corresponding to the external model.
Another advantage of the present invention is that it allows local non-rigid registration to an external model of the catheter guidance system and can compensate for non-linearities and non-homogeneities of the catheter guidance system. .
The above features as well as the aspects, features, details, uses, and advantages of the present invention will become apparent upon reading the following description and claims and studying the drawings.
Schematic diagram of localization system used for electrophysiological analysis.
The figure which illustrates the catheter used for an electrophysiological analysis.
The figure which shows typically the system which integrates a catheter guidance system into a three-dimensional image.
FIG. 4 illustrates a graphic user interface used to integrate a catheter guidance system into a three-dimensional image.
The present invention provides a system and method for local non-rigid registration to an external model or external image data of a catheter guidance system . That is, the present invention provides a method and system for converting a coordinate system in a catheter guidance system to a coordinate system of an external model or external image data. Here, “external” refers to a model or image data using a coordinate system different from that of the catheter guide system. The term “external image” as used herein means an external model or external image data with which the catheter guidance system is integrated. Preferably, the external image includes position information of a plurality of reference points. Typically, the position information is given in Cartesian coordinates in the external image coordinate system. Other coordinate systems such as a polar coordinate system, a spherical coordinate system, a cylindrical coordinate system, and the like may be used.
Typical external images include, but are not limited to, CT images, magnetic resonance images, ultrasound images, X-ray images, fluoroscopic images, and the like. The external image may be a specimen (template) of an image rather than a specific patient image. Further, the external image may be an image generated from position information acquired by the localization system, and that case is also within the scope of the present invention. As those skilled in the art will appreciate, if measured against a different origin, the data is also external according to the usage herein. Thus, the external image may be provided from a different localization system or from the same localization system with a different reference point (eg, a localization system collected during a previously performed procedure). Or the localization system data measured for different electrodes may be external images). The external image may be divided into parts or may not be divided. The external image may have been obtained from other suitable sources.
In the following, the present invention will be described in the context of cardiac procedures, particularly those performed in the ventricle, but the present invention provides useful results when used in other applications. Further, in the following, the present invention will be described for the case of a three-dimensional space, but those skilled in the art will understand how to apply the principles disclosed herein to any number of dimensions. Should be noted.
FIG. 1 performs an electrophysiological analysis of the heart by guiding a cardiac catheter, measures the electrical activity occurring in the heart 10 of the patient 11, measures the measured electrical activity, and / or Fig. 1 schematically shows a localization system 8 that displays information related to or indicative of measured electrical activity on a three-dimensional map. The system 8 can be utilized to generate an anatomical model of the patient's heart 10 utilizing one or more electrodes. The system 8 measures electrophysiological analysis data at a plurality of locations on the surface of the heart, and stores the measured data in association with the position information of the measurement point at which the electrophysiological analysis data was measured. It can be used to generate a data map for diagnosis. As will be appreciated by those skilled in the art and described in detail below, the localization system 8 determines, for example, the positions of objects in a three-dimensional space and those positions are determined with respect to at least one reference. Displayed as location information.
For simplicity of illustration, the patient 11 is schematically shown as an ellipse. A state in which three sets of surface electrodes (patch electrodes) are affixed to the surface of the patient 11 is shown, and three generally orthogonal three axes, the X axis, the Y axis, and the Z axis, are defined. The X-axis surface electrodes 12, 14 are applied to the patient along a first axis that faces the side of the patient's chest (eg, applied to the skin of the patient's armpit), It is called the right electrode. The Y-axis surface electrodes 18 and 19 are attached to the patient along a second axis (substantially orthogonal to the X-axis) that passes through the patient's inner thigh and neck, and are referred to as the left leg electrode and the neck electrode. Z-axis surface electrodes 16, 22 are attached to the patient along a third axis (substantially orthogonal to both the X and Y axes) through the sternum and spine of the patient's chest, It is said to be a back electrode. The heart 10 is located between three pairs of surface electrodes 12/14, 18/19, 16/22.
An additional surface electrode (eg, abdominal patch) 21 provides a reference and / or ground electrode for the system 8. The abdominal electrode 21 may replace the electrode 31 fixed in the heart, which will be described in detail later. Further, the patient 11 may have almost all electrodes attached to a predetermined position on a known electrocardiograph (ECG). Although not shown in FIG. 1, the system 8 is provided with ECG information.
The exemplary catheter 13 includes at least one electrode (eg, a tip electrode), which is illustrated. The catheter 17 of this embodiment is referred to herein as a movable electrode, a moving electrode, or a measurement electrode. Typically, a catheter 13 having a plurality of electrodes or a plurality of such catheters is used. In one embodiment, for example, the localization system 8 comprises up to 12 catheters inserted into the patient's heart and conduit and up to 64 electrodes provided on the catheters. Sometimes. Of course, this embodiment is merely illustrative. Any number of electrodes and catheters can be used in the present invention.
For purposes of disclosure, an example of a catheter 13 is shown in FIG. In FIG. 2, the catheter 13 extends into the left ventricle 50 of the patient's heart. The catheter 13 includes an electrode 17 disposed at the distal end and additional measurement electrodes 52, 54, and 56 disposed away from each other in the length direction. Since these electrodes 17, 52, 54, 56 are placed in the patient's body, the position of the individual electrodes is simultaneously measured by the localization system 8.
One suitable system for guiding the catheter 13 through the body of the patient 11 is the robotic surgical system disclosed in US patent application Ser. No. 11 / 647,272 filed on Dec. 29, 2006 (the '272 application). The contents of that application are hereby expressly incorporated by reference as if fully set forth herein. Of course, other mechanical, electro-mechanical, or robotic systems may be used to guide the catheter 13 through the patient 11 without exceeding the scope or scope of the present invention. Further, in some embodiments of the present invention, the catheter 13 is manually manipulated within the patient 11.
Returning to FIG. 1, an optional fixed reference electrode 31 (fixed to the wall of the heart 10) is placed on the second catheter 29. For compensation purposes, this electrode 31 may be stationary (eg fixed to or near the heart wall) or constant with respect to the moving electrode (electrodes 17, 52, 54, 56). The spatial positional relationship may be maintained. Therefore, the electrode 31 may be referred to as a guide standard or a local standard. The fixed reference electrode 31 can be used in addition to the surface reference electrode 21 or in place of the surface reference electrode 21. In many cases, coronary sinus electrodes or other fixed electrodes within the heart 10 can be used as a reference for measuring potential and displacement. That is, as will be described later, the fixed reference electrode 31 defines the origin of the coordinate system.
The individual surface electrodes are connected to a changeover switch 24, and an electrode pair is selected according to software executed by the computer 20. The changeover switch connects the surface electrode to the signal generator 25. For example, the computer 20 may be a conventional general-purpose computer, a dedicated computer, a distributed computer, or another type of computer. The computer may include one or more arithmetic processing units, for example, a single central processing unit capable of executing instructions for various purposes of the invention described in the specification. (CPU) or a plurality of processing units that are often referred to as parallel processing devices.
In general, a series of electric dipoles (eg, surface electrode pairs 12/14, 18 /) that are used to be driven to detect in order to be able to guide a catheter through a biologically derived conductor. 19, 16/22), a three-axis orthogonal coordinate system is generated. Instead, the orthogonal coordinate system may be decomposed. Any combination of surface electrode pairs may be driven as electric dipoles to provide a triangular electrode that is effective for detecting position. In addition, these non-orthogonal methodologies give the system flexibility. By algebraically combining the potentials measured by the moving electrodes, which are potentials generated with a predetermined driving arrangement (current flowing (source) and absorbing (sink)) with respect to an arbitrary axis, It is possible to obtain the same potential that would be obtained when a current is made to flow uniformly along the three axes.
Therefore, any two of the surface electrodes 12, 14, 16, 18, 19, and 22 can be selected as plus or minus of the electric dipole with respect to the ground electrode such as the abdominal patch 21, and in that state, the selection is made. The unconnected electrode measures the potential with respect to the ground voltage. The moving electrodes 17, 52, 54, 56 placed in the heart 10 are exposed to a field created by current pulses and can measure the potential with respect to a ground electrode such as the abdominal patch 21. In practice, the catheter in the heart may have more or less than the four electrodes shown and detect the electrode potential at each location. As described above, at least one electrode is fixed to the inner surface of the heart to form a fixed reference electrode 31. The electrode also measures the potential relative to ground voltage, such as the abdominal patch 21, and provides the origin of the coordinate system that the localization system 8 uses to measure the location. Data groups from individual surface electrodes, internal electrodes, and substantially electrodes are used to determine the position of the moving electrodes 17, 52, 54, 56 within the heart 10.
The measured potential is used to determine the position in the three-dimensional space of intracardiac electrodes such as moving electrodes 17, 52, 54, 56 relative to a reference point such as reference electrode 31. That is, the potential measured at the reference electrode 31 is used to determine the origin position of the coordinate system, and the potential measured at the moving electrodes 17, 52, 54, 56 is the moving electrodes 17, 52 with respect to the origin position. , 54, 56 are used to determine the position. Preferably, the coordinate system is a three-dimensional Cartesian coordinate system (x, y, z). The use of other coordinate systems, such as a polar coordinate system, a spherical coordinate system, a cylindrical coordinate system, and the like is also within the scope of the present invention.
As is apparent from the foregoing description, the data used to determine the position of the electrodes within the heart is measured with the surface electrode pairs applying an electric field to the heart. The data measured at the electrodes is also used to generate respiratory compensation values to improve the raw position data indicating the electrode position, as described in US Patent Publication No. 2004/0254437. The entire disclosure of US Patent Publication No. 2004/0254437 is incorporated herein by reference. The data measured at the electrodes is also used to compensate for changes in impedance within the patient's body, as disclosed in pending US patent application Ser. No. 11 / 27,580 filed on Sep. 15, 2005. . The entire disclosure of US patent application 11/227580 is incorporated herein by reference.
In short, the system 8 first selects one of the surface electrode pairs and then applies a current pulse. While a current pulse is being applied, electrical activity, for example, the potential measured by at least one other surface electrode and in vivo electrode, is measured and stored. Artificial compensation, such as respiration or impedance change compensation, may be performed as described above.
In a preferred embodiment, the localization / mapping system is the St. Jude Medical Atrial Fibrillation Division Incorporated Guidance and Visualization System EnSite NavX®. The system creates the electric field described above. However, other localization systems such as Biosense Webster's CARTO guidance and position measurement system or Northern Digital's AURORA® system can also be used for the present invention. Both systems use a local magnetic field instead of a local electric field. Localization / mapping systems disclosed in US Pat. Nos. 6,990,370, 6,978,168, 6,947,785, 6,939,309, 6,728,562, 6,640,119, 5,983,126, 5,697,377 and the like can also be used. The entire disclosure of the above patent is incorporated herein by reference.
The field generated by the localization system 8 is generally referred to as a localization field, whether it is an electric field as in the case of EnSite NavX®, a magnetic field as in the case of CARTO, or other fields. The Means for generating a field, such as electrodes 12, 14, 16, 18, 19, 22 are commonly referred to as localization field generators. As described above, the surface electrodes 12, 14, 16, 18, 19, and 22 also function as detectors that measure localization field characteristic values (for example, potentials measured by the moving electrodes 17, 52, 54, and 56). Then, the position information of the movable electrodes 17, 52, 54, 56 is determined. In the following, the present invention will be described mainly in the case of a localization system that generates an electric field, but those skilled in the art can use, for example, the electrodes 17, 52, 54, 56 as coils for detecting different elements of the magnetic field. It can be understood how to apply the principles of the present invention in other localization fields such as replacements.
As is apparent from the above description, the position information measured by the localization system 8 is unique to the localization system 8. That is, the position information describes the positions of the moving electrodes 17, 52, 54, 56 relative to the coordinate system of the localization system 8. It is preferable that the position information measured by the localization system 8 is integrated into an external image so that the position information measured by the localization system 8 can be mapped according to the external image. In that case, the external image uses a coordinate system different from that of the localization system 8 as described above. This is referred to as “integrating” the localization system 8 with the external image. If the localization system 8 is integrated into the external image, the positions of the electrodes 17, 52, 54, 56 measured by the localization system 8 in the coordinate system of the localization system 8 are displayed on the external image precisely and accurately. . The positions of the electrodes 17, 52, 54, and 56 are displayed based on the coordinate system of the external image.
A method for integrating a catheter guidance system (localization system 8) into a three-dimensional image is described with reference to FIG. FIG. 3 schematically illustrates a system 100 that integrates a catheter guidance system into a three-dimensional image. A three-dimensional external image of the heart chamber is obtained by retrieving the external image from a storage medium such as, for example, a hard disk, an optical disk, or a storage device that may be part of the computer system 20. As noted above, external images can be generated from CT, magnetic resonance, ultrasound, x-ray, fluoroscopy, or other suitable imaging or modeling method. The external image may be an image template (standard) instead of a specific patient specific image. Preferably, the external image includes position information of a plurality of reference points located on the surface of the heart chamber. When the external image is acquired, the shape 102 is displayed on the display device 23.
Then, for example, using the robotic surgical system disclosed in the '272 application for detecting the presence or absence of contact, the catheter 13 is guided by the robot so as to contact the surface of the heart chamber, or the catheter 13 is by operating the catheter 13 manually so as to contact the surface of the chamber, tools such catheter 13 is placed on a first surface position X 1 of the chambers of the heart. As described above (e.g., by measuring at least one characteristic value of the electric field or magnetic field at the first surface position X 1), position information of the first surface position X 1 is measured by the localization system 8. This position information is preferably expressed by coordinate values (x, y, z) with respect to the origin (reference electrode 31) of the localization system 8.
Then the user locates Y i on the three-dimensional external image corresponding to a first surface position X 1 of the heart chamber. Various visualization techniques, such as fluoroscopy and intracardiac echo technique (ICE), are used to assist the user in understanding the position of the catheter 13 located on the surface of the heart chamber. As a result, the work of locating Y 1 on the external image is facilitated. Clear anatomical features and / or physician experience and experience are utilized to ascertain whether X 1 and Y 1 correspond. For example, the physician's experience, if it is recognized as the first surface position X 1 which is located on the surface of the heart chamber is the vicinity of the mitral valve, the doctor mitral valve on the 3-dimensional external image the position in close proximity to designated as Y 1.
In some embodiments, by using the input device, on the three-dimensional shape of an external image displayed on the display device 23, by a specific or point to the first position Y 1, the first position Y 1 Identified. Preferred input devices include, but are not limited to, devices for pointing to locations such as a keyboard, keypad, mouse, trackball or trackpad, 2D or 3D joysticks, active or passive touch sensitive display devices It is. Preferably, the first position Y 1 includes position information expressed by coordinate values (x, y, z) measured with respect to the three-dimensional external image.
FIG. 4 shows an example of a graphic user interface (GUI; a screen that enables information exchange between the system and the user) used for carrying out the present invention. A three-dimensional external image shape 102 is displayed in a window 104. 3D joystick 106 (joystick with three input axis), on the shape 102, is utilized to click points to first position Y 1. To help the user visually understand the correspondence between X 1 and Y 1 , the second window 108 is generated from, for example, a perspective image, an ICE screen, or data obtained from the localization system 8. The catheter 13 in the heart chamber may be displayed by displaying a model or the like. By observing the position of the catheter 13 in the heart chamber of the second window 108, the user can specify the corresponding position Y 1 on the shape 102 displayed in the window 104. However, displaying only the shape 102 to the window 104, by experience and physician's experience in place of the video, it is within the scope or the scope of the present invention to identify a first surface position X 1.
Subsequently, a reference pair (X 1 , Y 2 ) is created by combining the first surface position X 1 measured by the localization system 8 and the corresponding position Y 1 on the three-dimensional external image. In some embodiments of the present invention, the pairing processing apparatus that is built into the computer system 20, automatically, the position information measured in the first surface position X 1, the position of the designated position Y 1 Combine information. The reference pair (X 1 , Y 1 ) is a pair of coordinate values (x, y, z). One coordinate value is relative to the origin of the localization system 8, and the other coordinate value is relative to the origin of the three-dimensional external image. Multiple reference pairs are combined by repeating the process of placing the catheter and pointing to the corresponding location.
The method described above is generally referred to as the “simple pick method” because the user of the system 100 is only required to point to point Y i on the external image (eg, shape 102 in window 104). Yes. The position information of the other elements of the reference pair, ie the surface position X i, is determined by measuring the position of the catheter 13 relative to the low colorization system 8 and automatically with the position information of the corresponding position Y i pointed to by the user. To be combined.
However, the “double pick method” is also possible. That is, instead of measuring the position of the catheter 8 relative to the localization system 8 to determine the position information of the point X i , a pick process (pointing process) is used to select the position X i relative to the localization system 8. be able to. For example, referring again to FIG. 4, the second window 108 may display a heart chamber surface model generated by the localization system 8. The model includes position information of a plurality of reference points located on the surface of the heart, measured for the localization system 8. Instead of or in addition to manipulating the catheter 13 in place, the user 106 utilizes a three-dimensional joystick to position the mitral valve at the position X i , for example, the shape displayed in the second window 108. You may point to the position close to. The user then moves to the window 104 and picks the corresponding position Y i on the external image shape 102. The position information of the positions X i and Y i is determined from the surface model and the external image, respectively, and combined with the reference pair (X i , Y i ). Of course, this two-pick method can be repeated many times to obtain a large number of reference pairs.
As will be appreciated by those skilled in the art, multiple reference pairs are used to generate a mapping function f that integrates the localization system 8 into a three-dimensional image. That is, the mapping function f converts position information described according to the coordinate system of the localization system 8 into position information described according to the coordinate system of the three-dimensional image.
If the localization system 8 is linear and homogeneous, affine transformations such as origin movement, rotation, and enlargement / reduction are preferred. In this case, it is preferable to use an affine transformation calculated according to a method for minimizing the mean square error. However, many localization systems are non-linear and non-homogeneous, and the affine transformation cannot accurately match the coordinate values in the localization system to the coordinate values in the external image. Therefore, it is preferable to use a mapping function that locally distorts the coordinate system of the localization system 8 and forcibly matches the coordinate value of the three-dimensional external image at the position of each reference pair. Thereby, the non-linearity and non-homogeneity of the localization system 8 can be compensated. That is, in each reference pair (X i , Y i ), for example, the value of the error function e that measures a mapping error that is the difference between f (X i ) and Y i is preferably substantially zero. This can be expressed by the equation that the absolute value of e = {f (X i ) −Y i } is substantially equal to zero. In some embodiments of the present invention, a suitably programmed conversion processor that is incorporated into the computer 20 derives the mapping function.
There are a number of algorithms that can be appropriately distorted to derive the mapping function f. One preferred algorithm is the thin plate spline algorithm. This algorithm is known to be used to fuse multiple images from different formats, such as PET and CT, or to integrate new image data into an existing image collection. . In general, the thin plate spline algorithm involves summing a plurality of weighted basis function fixed values. Typically, the number of weighted basis functions is equal to the number of reference pairs. The following paper explains the details of the thin plate spline algorithm. That article is incorporated herein by reference.
Bookstein, FL., Principal Warps: Thin Plate Splines and the Decomposition of Deformations. (IEEE Transactions on Pattern Analysis and Machine Intelligence. 1989. 11: 567-585.)
Bookstein, FL., Thin-Plate Splines and the Atlas Problem for Biomedical Images. (Proceedings of the 12 'International Conference on Information Processing in Medical Imaging. July, 1991.)
It should be understood that the thin plate spline algorithm may use a normalization parameter λ whose value is approximately equal to zero to smooth the resulting mapping function. Those skilled in the art will recognize and understand how normalization parameters should be applied to smooth the mapping function.
Another suitable distortion algorithm is the average coordinate value algorithm. The average coordinate value algorithm generally transforms a plurality of independent points in three dimensions into a three-dimensional closed triangular surface known as a “control mesh”. The average coordinate algorithm calculates a smoothed interpolation function through a three-dimensional space that, when deformed, deforms the vertices and triangles strictly without extrapolating roughly in the area away from the control mesh. can do. The following paper explains the details of the average coordinate algorithm. That article is incorporated herein by reference.
Ju T, Schaefer S, Warren J, Mean Value Coordinates for Closed Triangular Meshes. (ACM Transactions on Graphics. July 2005. 24 (3): 561-66.)
In some embodiments of the present invention, the coordinate value reference pairs (x, y, z) are the vertices of the control mesh, which are transformed from the 3D space of the localization system 8 to the 3D space of the external image. I am letting. Their vertices are connected to a two-dimensional Delaunay triangulation, for example by projecting them onto a sphere centered on a central grain and calculating the convex hull. Such a method can include all vertices, and the triangulation is nearly optimized when the reference pairs are well distributed on the inner surface of the heart chamber. The average coordinate value algorithm uses a control mesh and a deformed mesh to efficiently and smoothly convert an arbitrary coordinate value (x, y, z) according to the coordinate system of the localization system 8 to the coordinate system of the external image. .
Yet another suitable distortion algorithm is a radial basis function network algorithm. The algorithm is well known in neutral networks. The following papers and books explain the details of the radial basis function network algorithm. The article and book are incorporated herein by reference.
J. MoodY and C. J. Darken, "Fast learning in networks of locally tuned processing units," (Neural Computation, 1, 281-294 (1989).)
J. Park and LW. Sandberg, "Universal approximation using radial-basis-function networks," (Neural Computation, 3 (2): 246-257 (1991).)
A.G. Bors and I. Pitas, "Median Radial Basis Function Neural Network," (IEEE Trans. On Neural Networks, vol. 7, no. 6, pp. 1351-1364 (Nov. 1996).)
Martin D. Buhmann and MJ. Ablowitz, "Radial Basis Functions: Theory and Implementations," (Cambridge University (2003).)
Paul V. Yee and Simon Haykin, "Regularized Radial Basis Function Networks: Theory and Applications," (John Wiley (2001).)
Any number of reference pairs can be used to generate the mapping function f, but in order to generate a mapping function, at least three reference pairs (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ), more preferably at least 4 reference pairs (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ), (X 4 , Y 4 ) is used. One, two, or three reference pairs provide rigid registration (rigid integration) to the three-dimensional external image of localization 8. On the other hand, four or more reference pairs allow non-rigid registration of the localization system 8 to the three-dimensional external image . It is preferred if the localization system 8 is non-linear. Furthermore, it will be appreciated that the additional reference pairs improve the mapping function f and increase the effectiveness of integrating the localization system 8 into the external image.
It is further understood that the mapping function is normalized by smoothing the input data, i.e., the reference pair, prior to generating the mapping function by the various distortion algorithms described above. In some embodiments of the present invention, a kernel smoothing method is utilized to smooth the input data. One suitable kernel function is the derivative of a Gaussian function and is given by the general formula:
However, any kernel function that takes a maximum value at the center and smoothly decreases to zero as the distance from the center increases can be employed to implement the present invention. The input data can be smoothed by calculating the sum of the Y values weighted by the distance from the X position of the reference pair smoothed by the kernel function. As described above, the X position and the Y position are positions that define a reference pair. In the above general formula, x is the distance from the X position of each reference pair to the X position of the reference pair to be smoothed.
Other methods of smoothing the reference point pair are possible. One method is to first calculate the optimal stiffness integration for the reference pair. Even after the calculation, residual error vectors remain in each reference pair. A new reference pair can be created by moving the original reference pair along the vector in a direction in which the reference pairs approach each other. Non-rigid registration is calculated by utilizing the corrected new reference pair. If the reference pair moves over the entire length of the error vector, the coordinate value of the reference pair will be in the optimal position and the result will be equal to the stiffness integration. If the reference pair is not moved, the result is equal to the integration obtained when calculating to allow non-rigid registration immediately from the original reference pair. By adjusting the percentage by which the reference pair coordinate values are moved along the error vector, different levels of smoothing are obtained.
The above method can be executed by one or a plurality of computer systems, and software (for example, one or a plurality of software executed by one or a plurality of computer systems or processing units). Program) and may be embodied in hardware (eg, a series of instructions stored in one or more solid state devices), or a combination thereof. Also good. As described above, the computer may be a conventional general-purpose computer, a dedicated computer, a distributed computer, or another type of computer. Furthermore, the computer may include one or a plurality of processing devices such as a single central processing unit or a plurality of processing units usually referred to as parallel processing devices.
As used herein, computing device refers to a software program (such as a computer microprocessor and / or software program designed to be executed by one or more microprocessors running on one or more computer systems). Software module or separate program). As yet another example, each of the processes disclosed herein may be performed using one or more computer processors operating on one or more computer systems. Even so, the computerized system of the present invention can be configured to configure the method of the present invention.
Although several embodiments of the present invention have been described with a certain degree of specificity, those skilled in the art can make various modifications to the disclosed embodiments within the spirit and scope of the invention. For example, within the scope of the present invention, a reference pair may be created by guiding the catheter 13 to a corresponding position on the surface of the heart chamber in accordance with the guidance mark displayed on the shape 102 of the external model. it can. Similarly, multiple catheters 13 may be placed on the surface of the heart chamber, and the plurality of locations may be used to generate a surface model of the heart chamber. A plurality of positions may be “played back”, and each time a position is played back, the user may select a corresponding position on the external image. A plurality of images may be integrated with each other according to the systems and methods disclosed herein (eg, integrating CT images into magnetic resonance images and CT images into models generated with a catheter guidance system). .
It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting of the present invention. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.
A system that integrates a catheter guide system into a three-dimensional image,
Means for obtaining said three-dimensional image, which is a three-dimensional image of at least a part of the heart, and includes position information of a plurality of positions located on the surface of the heart;
Means for placing the tool on the first surface position X 1 of the heart,
Means for measuring said first position information of the surface position X 1,
Means for obtaining a first position Y 1 corresponding specified on the three-dimensional image,
A reference pair (X 1 , Y 1 ) is obtained by combining the position information of the first surface position X 1 measured by the catheter guide system and the position information of the corresponding first position Y 1 on the three-dimensional image. Means to make,
At least one of the reference pairs is used to convert a position in the catheter guidance system to a position on the three-dimensional image and to calculate a mapping error with an error function of approximately zero in each of the reference pairs. A system for generating a mapping function by non-rigid registration using any one of a distortion algorithm selected from the group consisting of a thin plate spline algorithm, an average coordinate value algorithm, and a radial basis function network algorithm .
The means for acquiring a three-dimensional image of at least a portion of the heart decomposes a CT image, a magnetic resonance image, an ultrasound image, an X-ray image, a fluoroscopic image, an image template, an image generated by a localization system, any of the above The system of claim 1, wherein a three-dimensional image of at least a portion of the heart is selected from a group consisting of the model or combination thereof.
It said means for obtaining a first position Y 1 corresponding identified in the three-dimensional image, and displays the shape of the display device of the three-dimensional image, which is specified in the form of a three-dimensional image using an input device corresponding and acquiring the first position Y 1, the system of claim 1.
Said means for combining the position information of the corresponding first position Y 1 on the position information and the 3-dimensional image of the first surface position X 1 measured by the catheter guidance system, first surface position measured by the catheter guidance system The reference pair (X 1 , Y 1 ) is created by automatically combining the position information of X 1 with the position information of the corresponding first position Y 1 specified on the shape of the three-dimensional image. The system of claim 3.
The means for generating the mapping function generates the mapping function using at least three reference pairs (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ). The system of claim 1, wherein:
The means for generating the mapping function uses at least four reference pairs (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ), (X 4 , Y 4 ). 6. The system of claim 5, wherein the mapping function is generated.
The means for generating the mapping function is to generate a mapping function using a thin plate spline algorithm,
The thin plate spline algorithm includes summing a fixed number of weighted basis functions;
The fixed number of the weighted basis functions is equal to the number of the reference pairs;
The system of claim 1, wherein the mapping function compensates for inhomogeneities of the catheter guidance system and calculates a mapping error with an error function of approximately zero in each of the reference pairs (X i , Y i ). .
8. The system of claim 7, further comprising means for smoothing the mapping function using normalization parameters.
The system of claim 8, wherein the normalization parameter is approximately zero.
The means for generating the mapping function is to generate the mapping function using an average coordinate value algorithm,
The mean coordinate algorithm compensates for inhomogeneities in the catheter guide system and calculates a mapping error with an error function of approximately zero for each of the reference pairs (X i , Y i ). System.
At least 4 by the means for measuring position information of the first surface position X 1, the means for obtaining the corresponding first position Y 1 , and the means for creating the reference pair (X 1 , Y 1 ). A pair of reference pairs is obtained,
The means for generating the mapping function further comprises means for generating a closed triangular surface model for at least a portion of the heart;
The system of claim 10, wherein the vertices of the closed triangular surface correspond to at least four of the reference pairs.
The means for generating the mapping function generates the mapping function using at least three reference pairs and an average coordinate value algorithm;
The average coordinate value algorithm compensates for inhomogeneities of the catheter guide system and calculates a mapping error in which the error function is approximately zero in each of the reference pairs (X i , Y i ). 1 system.
The means for generating the mapping function is to generate the mapping function using a radial basis function network algorithm;
The radial basis function network algorithm compensates for inhomogeneities of the catheter guidance system and calculates a mapping error with the error function being approximately zero in each of the reference pairs (X i , Y i ). Item 1. The system according to item 1.
It said means is characterized by detecting the electric field characteristic values of at least said first surface position X 1, system of claim 1 for measuring the first position information of the surface position X 1.
It said means includes detecting a characteristic value of the magnetic field at least the first surface position X 1, system of claim 1 for measuring the first position information of the surface position X 1.
The means for generating the mapping function further comprises means for smoothing the at least one reference pair prior to generating the mapping function using at least one of the reference pairs. The system of claim 1.
17. The system of claim 16, wherein the means for smoothing at least one of the reference pairs smooths at least one of the reference pairs using a kernel smoothing method.
The means for smoothing at least one of the reference pairs;
Using at least one reference pair to calculate a stiffness integration that results in an error vector between elements in at least one of the reference pairs;
Redefining the reference pair by moving the elements of the reference pair closer to each other along the error vector resulting from the stiffness integration;
17. The system of claim 16, wherein the means for generating the mapping function generates the mapping function using at least one redefined reference pair.
A system that integrates a catheter guidance system into at least an image of the heart,
A catheter inserted into at least a portion of the heart;
A catheter guide system for placing a catheter at a position X located on at least a part of the heart and measuring position information of the position X located on at least a part of the heart;
An image of at least a portion of the heart and including location information for a plurality of locations located on a surface of at least a portion of the heart;
An input device connected to an image of at least a part of the heart and allowing a user to select a position Y on the image corresponding to a position X on the surface of at least a part of the heart where the catheter is placed;
A combination processing device that combines the measured position information of the position X on the surface of at least a part of the heart where the catheter is placed and the position information of the selected position Y to create a reference pair (X, Y);
A mapping function f for converting the position of the catheter guide system in n-dimensional space into the position of the image in n-dimensional space, and the difference between the value of f (X) and the value of Y in each reference pair is substantially zero. A non-rigid registration mapping function f using any one of a distortion algorithm selected from the group consisting of a thin plate spline algorithm, an average coordinate value algorithm, and a radial basis function network algorithm A system comprising a conversion processing apparatus.
20. The system of claim 19, wherein the conversion processor is programmed with a thin plate spline algorithm.
20. The system of claim 19, wherein the transformation processor is programmed with an average coordinate value algorithm.
20. The system of claim 19, wherein the transformation processor is programmed with a radial basis function network algorithm.
A catheter guidance system generates a local electric field in at least a portion of the heart and measures position information of a position X on at least a surface of the heart based on a characteristic value of the local electric field encountered by the catheter; The system of claim 19.
A catheter guidance system generates a local magnetic field in at least a portion of the heart and measures position information of position X on the surface of at least a portion of the heart based on a characteristic value of the local magnetic field encountered by the catheter; The system of claim 19.
An image of at least a portion of the heart, including an n-dimensional location information of a plurality of locations located on a surface of at least a portion of the heart;
A model of at least a portion of the heart, including a plurality of n-dimensional location information located on a surface of at least a portion of the heart and measured with respect to the catheter guidance system;
An input device that allows a user to select a position Y on an image of at least a portion of the heart and to select a position X on a model of at least a portion of the heart;
Combining the position information of the position Y selected on the image of at least a part of the heart with the position information of the position X selected on the model of at least a part of the heart to create a reference pair (X, Y) A processing device;
A mapping function f for converting a position in the catheter guiding system into a position in the image, and in each reference pair (X, Y), a distortion in which the difference between the value of f (X) and the value of Y is almost zero An algorithm programmed to generate a mapping function f by non-rigid registration using any distortion algorithm selected from the group consisting of a thin plate spline algorithm, an average coordinate value algorithm and a radial basis function network algorithm A system comprising a conversion processing device.
The position Y selected on an image of at least part of the heart and the position X specified on a model of at least part of the heart correspond to a common position on the surface of at least part of the heart. Item 25. The system according to Item 25.
JP2009552798A 2007-03-09 2008-02-26 System and method for local non-rigid registration of a catheter guide system to image data or models Active JP5866136B2 (en)
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