Apparatus and method for determining the position of an invasive device - Patent Application 20070122997

Abstract

This is achieved by an invasive device arrangement and method, in which an optical shape detection system for detecting the position and / or shape of an invasive device is provided, the system is configured to locate at least one point Pi on the invasive device at a position xi, yi, zi with several error margins (2Δxi, 2Δyi, 2Δzi) within a region of interest, and to locate and reconstruct at least one point Pi on the invasive device at a position with several error margins (2Δxi, 2Δyi, 2Δzi) within the region of interest by the optical shape detection system. A magnetic resonance imaging system is also provided for measuring the position xi, y, z of the point Pi on the invasive device within the error margin in the region of interest in at least one spatial direction by the magnetic resonance imaging system, a signal of magnetization at the error margin is read out by the magnetic resonance imaging system, and the position of the invasive device is determined based on the signal.

Description

[Technical Field]

[0001] The present invention relates to the field of determining the position of an invasive device, and in particular to determining the position of an invasive device based on optical shape detection supported by diagnostic imaging. [Background technology]

[0002] MR guidance of intravascular procedures is a promising approach in many applications due to the superior soft-tissue contrast of MRI compared with traditional fluoroscopy or ultrasound guidance. While the variety of contrast and physiological parameters is a major advantage of MR, visualization and localization of invasive devices such as catheters differs from fluoroscopy or ultrasound and involves additional technical effort and safety concerns. Visualization can be achieved passively by contrast due to the absence of water within the invasive device, by contrast due to contrast agents present within the invasive device, or actively by integrating a wired μ-MR receiver coil within the invasive device.

[0003] Fiber optic shape sensing makes it possible to detect the shape of flexible composite optical fibers in 3D with high temporal and spatial resolution. It is based on the optical detection of strains of individual optical cores along the composite fiber by either fiber Bragg gratings or Rayleigh scattering. The known relative configuration of the cores makes it possible to reconstruct the configuration of the composite fiber from the strain data.

[0004] Passive MR visualization requires that the invasive device be visible in real-time MR imaging slices. Therefore, both the invasive device and the imaging slices must be manipulated sequentially, which is clearly inferior to the rapid and uncomplicated visualization offered by fluoroscopy. The imaging slices must be shifted and angled to depict at least a portion of the invasive device shaft. Primarily, 3D invasive device configurations allow visualization of only a short portion of the shaft within a single slice. For these reasons, passive visualization is rarely applied to invasive devices, but rather to rigid devices such as needles and ablation devices.

[0005] Active MR tracking was clinically demonstrated over a decade ago, but it could not be applied clinically for a long time because the wiring of the μ-coils inside the invasive device represented a safety hazard due to potential RF heating of the invasive device during MR imaging. This problem has been solved by introducing miniature transformers into the wiring. However, in practice, active invasive device tracking can only localize two or a maximum of three points along the invasive device, because each point must be equipped with a μ-coil, necessitating a separate cable within the invasive device shaft, which has a diameter of approximately 500 μm. This is a major disadvantage compared to competing means of invasive device visualization in other modalities, including electromagnetic localization devices that display all or at least most of the distal shaft of the invasive device. Furthermore, even the most recent implementations of MR active tracking technology still have a relatively high failure rate due to internal wire breakage, primarily resulting from repeated sharp bending of the invasive device.

[0006] The fiber optic real-shape (FORS) technique is based on measuring mechanical strain along many points on a fiber, and the shape is reconstructed by integrating these strain values. Therefore, errors in individual strain measurements sum, resulting in a shape error at a known fixed point at the proximal end of the fiber that increases from zero toward the fiber tip. Current implementations of the FORS technique achieve a tip localization accuracy (distance to true position) of 6 mm over a 1.8 m length of fiber. Systematic effects such as pulling forces on the fiber cause the majority of this error. The accuracy (typical variation of repeated measurements in a fixed fiber configuration) is approximately 1 mm at 50 Hz, which is relatively small. However, an overall tip localization accuracy of 6 mm is still too large for many invasive device or catheter applications, particularly cardiac catheter ablation, which is performed using catheters with diameters of 1.3 mm to 2 mm.

[0007] US patent application US2014 / 155737 relates to curved multiplanar rendering (MPR) of 3D reconstructed MR image data based on the shape of a catheter measured by fiber optic shape (FOS) detection. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide an apparatus and method for determining the position of an invasive device based on optical shape detection supported by diagnostic imaging, for example by magnetic resonance CT, so that the accuracy of position determination by optical shape detection is improved. [Means for solving the problem]

[0009] According to the present invention, this object is addressed by the subject matter of the independent claims. Preferred embodiments of the invention are set forth in the dependent claims.

[0010] Therefore, according to the present invention, there is provided an apparatus for determining the position of at least one invasive device, comprising: at least one optical shape detection system configured to measure at least one point Pi on the invasive device at a position xi, yi, zi with some error margin within a region of interest, the at least one optical shape detection system being configured to correct the position xi, yi, zi of the point Pi on the invasive device determined at the position xi, yi, zi in a diagnostic imaging system, for example a magnetic resonance imaging (MRI) system; the at least one optical shape detection system configured to measure the position xi, yi, zi of the point Pi on the invasive device within the error margin within the region of interest in at least one spatial direction; and at least one computing system, the computing system being configured to correct the position x, y, z of the point OOD on the invasive device determined at the position x, yi, zi, the point Pi on the invasive device determined by the MRI system on which the apparatus is provided indicates the actual position of the invasive device.

[0011] The basic idea of ​​the present invention is that FORS technology is integrated with a diagnostic imaging system, such as a magnetic resonance imaging system, and FORS data is augmented by dedicated MR imaging to improve the accuracy of shape detection to a fraction of the diameter of the invasive device along the entire invasive device. FORS is used to localize isolated predetermined points Pi on the invasive device in 3D. Dedicated MR projections and imaging sequences are used to cover these regions of interest with high resolution but a very limited FOV and therefore a very short acquisition time. Dedicated reconstruction of these MR data resolves the exact locations of the points, which is used to correct the global shape reconstruction.

[0012] According to a preferred embodiment, the magnetic resonance imaging system is further configured together with the magnetic resonance imaging system to excite magnetization within an error margin in at least one spatial direction by exciting a position x-position x-slice and / or x-slice centered at Pi at a position xi, yi, zi and perpendicular to the direction vector ni, the magnetic resonance imaging system is configured to read out signals of the excited z-slice and / or y-slice and / or x-slice with a readout gradient along the x-direction and / or a readout gradient along the z-direction, the magnetic resonance imaging system is further configured to execute a scheme for finding signal suppression in the signals of the excited z-slice and / or y-slice and / or x-slice and determining the position xi, y, zi of the point Pi on the invasive device based on the signals.

[0013] According to another preferred embodiment, the invasive device comprises at least one MR marker along the extension of the invasive device. In order to easily extract the location of points Pi on the invasive device from the MR data, the invasive device can be equipped with MR markers at points Pi.

[0014] Preferably, the MR marker is selected from the list of MR markers: paramagnetic agents, ferromagnetic agents, ferrimagnetic agents, antiferromagnetic agents, resonant pick-up radio frequency (RF) coils, inductively coupled RF coils. For example, passive or active MR markers can be provided.

[0015] In another aspect of the invention, the problem is a method for determining the position of an invasive device, the method comprising: Providing an invasive device; providing magnetic resonance imaging (MRI); providing an optical shape detection system for detecting the position and / or shape of the invasive device, the system detecting a position x with some error margin in a region of interest; i , y i , z i At least one point P on the invasive device iconfigured to locate the The optical shape detection system detects a position x in the region of interest. i , y i , z i At least one point P on the invasive device i and locating and reconstructing The magnetic resonance imaging system detects a point P on the invasive device within the error margin in the region of interest in at least one spatial direction. i Position x of i , y i , z i measuring reading out signals of magnetization within the error margin by a magnetic resonance imaging system; determining a location of the invasive device based on the signal; A calculation system calculates a point P on the invasive device in the region of interest determined by the magnetic resonance imaging system. i Position x of i , y i , z i a point P on the invasive device in the region of interest determined by the optical shape detection system at i Position x of i , y i , z i and correcting the This is achieved by a method comprising:

[0016] Briefly, the present invention relates to determining the location of an invasive device based on a combination of (i) optical shape detection and (ii) diagnostic imaging, particularly magnetic resonance CT, x-ray imaging, or computed tomography. According to the present invention, a relatively low-precision determination of the invasive device's location is performed by optical shape detection. This initial location is then used to position a limited volume (slab) around the initial location for radio frequency (RF) excitation, and a more accurate determination of the invasive device's location within the slab is derived from MR image information of the RF-excited slab. In a specific embodiment, this is performed by projecting the magnetic resonance signals forming the slab in three directions back to the location of the invasive device within the slab. This determination takes advantage of the fact that the MR response of the invasive device's material differs from that of the surroundings (tissue, primarily water) within the slab.

[0017] This method relates to the operation of the technical device described above, i.e., how the position of an invasive device is determined by a computer using an optical shape detection system and a magnetic resonance imaging (MRI) system. In this method, the position and orientation of the invasive device are determined optically and by MRI, i.e., non-invasively. There is no functional link, and therefore no physical causal relationship, between the constituent steps performed on the invasive device and the surgical procedure produced on the body by the device. Therefore, the method and effects produced by the device on the human or animal body do not qualify as methods for treatment at all. Furthermore, treatment steps for surgical procedures on the body are not included in this method, and no such steps are covered by this method. In particular, this method does not include or encompass invasive steps that represent substantial physical interventions on the body, which require specialized medical expertise to be performed and, even when performed with the required professional care and expertise, involve substantial health risks. In particular, it may be provided that this method is not applied to the human or animal body.

[0018] According to a preferred embodiment, the step of measuring the position xi, yi, zi of a point Pi on the invasive device within an error margin within the region of interest includes the steps of exciting, by a magnetic resonance imaging system, z-slice and / or y-slice and / or x-slice centered on the point Pi at the position xi, yi, zi and perpendicular to the direction vector ni of the invasive device, reading out signals of the excited z-slice and / or y-slice and / or x-slice within the error margin by the magnetic resonance imaging system, and determining the position of the invasive device based on the signals.

[0019] Preferably, the step of reading out magnetization signals within an error margin comprises reading out signals of excited z slices and / or y slices and / or x slices using readout gradients along the x direction and / or along the y direction and / or along the z direction.

[0020] More preferably, the thickness of the z-slice and / or y-slice and / or x-slice is 2 to 3 times the thickness of the invasive device.

[0021] Preferably, the step of determining the position of the invasive device based on the signals includes detecting the at least one point P on the invasive device at the positions xi, yi, zi by an optical shape detection system. i Based on the localization and reconstruction of x-slice signals, performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals outside the region x-Δxi to x+Δxi and / or yi-Δyi to y+Δyi and / or z-Δzi to z+Δzi.

[0022] According to another preferred embodiment, the step of executing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals comprises: selectively exciting a z-slice and / or a y-slice and / or an x-slice; performing a selective y slice refocusing pulse at a slice center of yi and a slice thickness of 2Δyi, and / or performing a selective x slice refocusing pulse at a slice center of xi and a slice thickness of 2Δxi, and / or performing a selective z slice refocusing pulse at a slice center of zi and a slice thickness of 2Δzi; reading out the signals along the x-direction and / or the z-direction and / or the y-direction; The method is performed by a spin echo scheme with

[0023] Preferably, the step of performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals comprises: Exciting and spoiling the signal in the region outside yi - Δyi to yi + Δyi and / or xi - Δxi to x + Δxi and / or zi - Δzi to zi + Δzi; selectively exciting a z-slice and / or a y-slice and / or an x-slice; reading out the signals along the x-direction and / or the z-direction and / or the y-direction; This is performed by a saturation scheme with

[0024] Preferably, the step of executing a scheme for detecting signal suppression of the excited z-slice and / or y-slice and / or x-slice signal comprises: The signal train along the x direction, y direction, and / or z direction is calculated by dividing the signal train into points P i Step of exciting by 2d pulse centered at This is performed by a 2d excitation scheme with

[0025] At least one point P on the invasive device at positions xi, yi, zi is detected, preferably by an optical shape detection system. i The step of locating and reconstructing At least one point P on the invasive device iwherein the invasive device has at least one MR marker along an extension of the invasive device. It has.

[0026] Preferably, locating and reconstructing, by the optical shape sensing system, at least one point Pi on the invasive device at a position xi, yi, zi includes locating and reconstructing points at a tip point of the invasive device and / or at least one point Pi along the shaft of the invasive device.

[0027] More preferably, the step of locating and reconstructing at least one point Pi on the invasive device in the intervals xi, yi, zi includes the steps of first locating a tip point of the invasive device, then locating and reconstructing a point half the length of the invasive device, and then locating and reconstructing a point one-quarter the length of the invasive device.

[0028] According to one embodiment of the present invention, when the step of exciting magnetization within the error margin in a region of interest is performed in a first spatial direction by the magnetic resonance imaging system, the method includes a step of exciting magnetization within the error margin in the region of interest in at least another spatial direction.

[0029] In another aspect of the present invention, the above object is achieved by a computer program product comprising instructions that cause a computer to carry out the steps of the above method when the program is executed by a computer.

[0030] In yet another aspect of the present invention, this object is achieved by a software package for a magnetic resonance (MR) imaging system, the software package including instructions for controlling the above-mentioned magnetic resonance imaging (MRI) system.

[0031] Further embodiments of the present invention can utilize diagnostic imaging modalities such as computed tomography or x-ray imaging. Optical shape detection provides the device tip position within an error margin, denoted as V and representing the section 3D volume. Optical shape detection also provides the orientation of the tip portion of the section device, denoted as orientation vector k. The following embodiments propose to use this knowledge to improve the detection of the exact tip position in x-ray or CT.

[0032] In one embodiment of the present invention based on x-ray imaging, it is proposed to project the volume V onto an x-ray image, effectively creating a 2D region of interest within this image (ROI). It is proposed to restrict the area for searching for the device tip to this ROI. Depending on the known size of the device, some extra margin can be added. This ensures that the ROI completely covers the periphery of the device. Already, this simple measure significantly improves the robustness of device tip detection in terms of increased sensitivity and reduced false positive rate (increased specificity).

[0033] For device detection itself, any image processing algorithm can be used to locate the device within the ROI, preferably using a known orientation vector k and device size. In one embodiment, a line filter is used to enhance any linear structures within the ROI that correspond to the projection k' of orientation k onto the image plane. After identifying the exact line structure corresponding to the device, a further filter can be used to accurately determine the end of the line along direction k', i.e., the device tip.

[0034] An embodiment of the present invention based on computed tomography (CT) first proposes using the longitudinal (z) extent of the volume V. The search range of the device can be limited to the corresponding z extent of the CT detection / reconstruction volume. Second, similar to the X-ray embodiment, the known orientation k is exploited, here by directly enhancing the line structure with a filter. Finally, the end of the line along k can be searched to detect the tip position.

[0035] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter, but such embodiments do not necessarily represent the full scope of the invention, and reference is therefore made to the claims and this specification for interpreting the scope of the invention. [Brief explanation of the drawings]

[0036] [Figure 1] 1 shows a schematic diagram of an invasive device with a point Pi at a position xi, yi, zi localized by an optical shape sensing system and an excited z-slice, according to an embodiment of the present invention. [Figure 2] 1 shows a flow diagram for determining the position of an invasive device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] FIG. 1 is a schematic diagram of an invasive device 1 having a point Pi at a location xi, yi, zi, which is being localized by an optical shape detection system and excitation z-slice 2 according to the present invention. Point Pi is localized by FORS on the invasive device 1 to be at location xi, yi, zi; however, due to limited accuracy, the true location may be contained within an error margin 2Δxi, 2Δyi, 2Δzi centered at xi, yi, zi. The size of this error margin 2Δxi, 2Δyi, 2Δzi may vary from point to point and, therefore, be indexed, and without further prior knowledge, generally increase in size toward the tip of the invasive device 1. FOR reconstruction also provides a direction vector n, of the invasive device 1 at point Pi. To improve the accuracy of localization of Pi in the x-direction x, the MR scanner measures the locations xi, yi, zi of point Pi on the invasive device 1. In particular, as shown in Figure 1, a slice 2 can be excited that is about 2 to 3 times the thickness of the invasive device 1, centered at xi, yi, zi, and perpendicular to the direction vector ni. A readout of the signals in that slice 2 with a readout gradient along the x-direction x provides a projection of all signals within that slice 2 integrated along the y-direction y. Because there is no water within the invasive device 1, in this projection the true position x of the device is ti A small signal dip at y is expected. However, signal non-uniformity from body tissue across slice 2 also provides signal variation, so that the small signal reduction due to invasive device 1 is likely to be obscured. Therefore, it is proposed that the signal from slice 2 outside yi -Δyi to yi +Δyi be suppressed prior to signal readout. As a result, the projection contains only the signal integrated along y in that small region. Now, the absence of signal within the device results in a significant reduction in signal in the projection. The location of this signal dip is determined by the true position x of the device. ti From xi - Δxi to xi + Δxi, we only need to search for this signal dip, since we know it in advance. Signal suppression can be performed by various methods.

[0038] In one embodiment of the present invention, signal suppression is performed by a spin echo scheme. After z-slice selective excitation, a y-slice selective refocusing pulse is performed at the slice center of yi and with a slice thickness of 2Δyi. A subsequent readout in the x-direction x acquires signals only from the cross section of the excited z-slice 2 and refocused y-slice. In another embodiment, signal suppression is performed by a saturation scheme, where signals in the region outside yi -Δyi to yi +Δyi are excited and impaired, followed by z-slice 2 selective excitation and readout along the x-direction x.

[0039] In a further embodiment of the present invention, signal suppression is performed using a 2D excitation scheme. 2D pulses are used to excite only a column of signals along xi, centered at xi, yi, and zi, with widths yi and zi. For ease of explanation and annotation, the invasive device 1 is oriented along the z-axis z in FIG. 1. An approximate orientation of the invasive device 1 at point Pi can be derived from the FORS data to orient a selected slice 2 perpendicular to the invasive device 1. This results in minimal partial volume effects caused by the finite width of slice 2 and the pixels in the projection readout.

[0040] The above embodiment describes the acquisition of MR projection data to improve the localization of Pi in the x-direction x. To improve the localization in the y-direction and the z-direction y, z in one embodiment of the present invention, analogous steps can be performed in at least the other spatial directions x, y, z.

[0041] The direction along the invasive device 1, in the embodiment shown in FIG. 1, the z-direction, presents a slightly different problem because the invasive device 1 does not provide a priori structures that can be visualized by MR. However, points Pi may be selected to coincide with structures of the invasive device 1 that already provide some MR contrast. In another embodiment of the present invention, points Pi can be equipped with passive MR markers known in the art to provide sufficient MR contrast. Passive MR markers are paramagnetic, ferromagnetic, ferrimagnetic, and antiferromagnetic metals, metal alloys, and metal compounds. They are preferably embedded as particles in a plastic matrix. Additionally, active markers such as resonant pickup radio frequency (RF) coils or semi-active inductively coupled RF coils can be provided. Even knowing only the xi and y coordinates of points Pi improves FORS localization. This allows the true location of points Pi to be obtained with high accuracy. Therefore, FORS reconstruction can be performed segment by segment, and the geometry between those points must be solved. Initially, MR localization of the tip of the invasive device 1 provides the greatest information gain for FORS reconstruction. In one embodiment, it may be intended to first localize the tip point of the invasive device 1 using MR and continue with semi-localization using points half the length of the invasive device 1, then one-quarter the length, etc.

[0042] FIG. 2 shows a flowchart of a method for determining the position of an invasive device 1 according to an embodiment of the present invention. The method begins in step 200 by providing at least one invasive device 1, a magnetic resonance imaging (MRI) system, and an optical shape sensing system. The optical shape sensing system is configured to determine the position and / or shape of the invasive device 1. Optical shape sensing, or fiber-optic shape sensing, allows for detecting the shape of a flexible composite optical fiber in 3D with high temporal and spatial resolution. It is based on optical detection of the strain of individual optical cores along the composite fiber, either by fiber Bragg gratings or Rayleigh scattering. The known relative configuration of the cores allows for reconstructing the configuration of the composite fiber from the strain data.

[0043] In step 210, at least one point Pi on the invasive device 1 at a position xi, yi, zi is localized and reconstructed by the optical shape detection system with some error margins 2Δxi, 2Δy, 2Δzi within the region of interest 3.

[0044] In step 220, magnetization is excited by the magnetic resonance imaging system in at least one spatial direction x, y, z with an error margin 2Δxi, 2Δyi, 2Δzi within the region of interest 3. In this embodiment, the magnetization can be excited as z- and / or y- and / or x-slice 2 at positions xi, yi, zi, centered on point Pi and perpendicular to the direction vector n i of the invasive device 1 comprising the magnetic resonance imaging system. For example, to improve the accuracy of localization of Pi in the x-direction x, the MR scanner excites a slice 2 centered at xi, yi, zi and perpendicular to the direction vector n i , approximately two to three times the thickness of the invasive device 1. Therefore, it can be foreseen to derive an approximate orientation of the invasive device 1 at point Pi from the FORS data and orient the selected slice 2 perpendicular to the invasive device 1. This results in minimal partial volume effects caused by the finite width of slices and pixels in the projection readout.

[0045] In step 230, signals of magnetization with error margins 2Δxi, 2Δyi, and 2Δzi are read out by the magnetic resonance imaging device. In one embodiment of the present invention, signals of excited z slices and / or y slices and / or x slice 2 are read out by the magnetic resonance imaging system with readout gradients along the x direction x and / or along the y direction y and / or along the z direction z. For example, readout of signals of slice 2 with a readout gradient along the x direction x provides a projection of all signals in that slice 2 integrated along the y direction y. Since there is no moisture in the device, the device x tiA small signal dip is expected in this projection at the true position of . However, signal heterogeneity from body tissue across the slice also provides signal variation, so that the small signal reduction by the device is likely to be obscured. Therefore, it is proposed that the signal from slice 2 outside yi - Δyi to yi + Δyi be suppressed prior to signal readout. As a result, the projection contains only the signal integrated along y in that small region. Here, the absence of signal within the device results in a significant reduction in signal in the projection. The location of this signal dip is determined by the true position x of the invasive device 1. ti corresponds to. Since xi -Δxi to xi +Δxi are known in advance, it is only necessary to search for this signal dip. Therefore, determining the position of the invasive device 1 based on the signals includes implementing a scheme for signal suppression of the signals of the excited z slices and / or y slices 2 based on the signals, xi -Δxi to xi +Δxi and / or yi -Δyi to yi +Δyi and / or zi -Δzi to z -Δzi based on localization and reconstruction of at least one point Pi on the invasive device 1 at positions xi, yi, zi by the optical shape detection system.

[0046] Signal suppression can be performed in various ways. For example, the steps of performing a scheme for signal suppression of excited z-slice and / or y-slice and / or x-slice 2 signals include: selectively exciting a z slice and / or a y slice and / or an x ​​slice; performing a selective y-slice refocusing pulse with a slice center at yi and a slice thickness of 2Δyi, and / or performing a selective x-slice refocusing pulse with a slice center at xi and a slice thickness of 2Δxi, and / or performing a selective z-slice refocusing pulse with a slice center at zi and a slice thickness of 2Δz; reading out signals along the x-direction x and / or the z-direction z and / or the y-direction y; The method is performed by a spin echo scheme including:

[0047] In another embodiment of the present invention, the step of performing a scheme for signal suppression of excited z-slice and / or y-slice and / or x-slice 2 signals comprises: Exciting and spoiling the signal in the region outside yi - Δyi to yi + Δyi and / or xi - Δxi to x + Δxi and / or zi - Δzi to zi + Δzi; selectively exciting a z-slice and / or a y-slice and / or an x-slice; reading out the signals along the x-direction and / or the z-direction and / or the y-direction; This is performed by a saturation scheme with

[0048] In a further embodiment of the invention, the step of performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice 2 signals comprises: Exciting a sequence of signals along the x-direction x and / or the y-direction y and / or the z-direction z by a 2d pulse centered at point Pi at positions xi, yi, zi. This is performed by a 2d excitation scheme including

[0049] The measurement data thus obtained is used to determine the position of the invasive device 1 based on the signals.

[0050] In step 240, the positions xi, yi, zi of the points Pi on the invasive device 1 within the region of interest 3 determined by the optical shape detection system are corrected with the positions xi, yi, zi of the points Pi on the invasive device 1 within the region of interest 3 determined by the calculation system relative to the actual position of the invasive device 1.

[0051] While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered exemplary or illustrative and not restrictive, and the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. Moreover, for the sake of clarity, not all elements in the drawings have been labeled with reference signs. The following describes embodiments of the present invention. (Appendix 1) 1. A device for determining the location of an invasive device, comprising: at least one invasive device; at least one optical shape detection system configured to determine the position and / or shape of the invasive device, the optical shape detection system further configured to locate and reconstruct at least one point Pi on the invasive device at a position xi, yi, zi with some error margin within a region of interest; a diagnostic imaging system configured to measure positions xi, yi, zi of points Pi on the invasive device within the error margin in the region of interest in at least one spatial direction; at least one computing system configured to correct positions xi, yi, zi of points Pi on the invasive device determined by the optical shape detection system to actual positions of the invasive device using positions xi, yi, zi of points Pi on the invasive device determined by the diagnostic imaging; and An apparatus having: (Appendix 2) 2. The apparatus of claim 1, wherein the diagnostic imaging system is a magnetic resonance imaging system, a computed tomography imaging system, or an X-ray imaging system. (Appendix 3) 2. The apparatus of claim 1, wherein the diagnostic imaging system is a magnetic resonance imaging system, and the magnetic resonance imaging system is further configured to excite magnetization within the error margin in the region of interest in at least one spatial direction by exciting z- and / or y- and / or x-slices centered on a point Pi at the position xi, yi, zi and perpendicular to a direction vector by the magnetic resonance imaging system, the magnetic resonance imaging system configured to read out signals of the excited z- and / or y- and / or x-slices with readout gradients along the x- and / or y- and / or z-directions, and the magnetic resonance imaging system is further configured to detect signal suppression in the signals of the excited z- and / or y- and / or x-slices and execute a scheme for determining positions xi, yi, zi of point Pi on the invasive device based on the signals. (Appendix 4) 4. The apparatus of any one of claims 1 to 3, wherein the diagnostic imaging system is a magnetic resonance imaging system and the invasive device has at least one MR marker along an extension of the invasive device. (Appendix 5) 5. The apparatus of claim 4, wherein the MR marker is selected from the list of MR markers: paramagnetic agents, ferromagnetic agents, ferrimagnetic agents, antiferromagnetic agents, resonant pick-up RF coils, and inductively coupled RF coils. (Appendix 6) 1. A method for determining a position of an invasive device, the method comprising: - providing an invasive device; - providing a diagnostic imaging system; - providing an optical shape detection system for detecting the position and / or shape of the invasive device, said system being configured to locate at least one point Pi on the invasive device at a position xi, yi, zi having some error margin in a region of interest; - locating and reconstructing by the optical shape detection system at least one point Pi on the invasive device at a position xi, yi, zi in the region of interest; - measuring, by the magnetic resonance imaging system, positions xi, yi, zi of points Pi on the invasive device within the error margin in at least one spatial direction in the region of interest; - correcting, by a calculation system, the positions xi, yi, zi of points Pi on the invasive device in the region of interest determined by the optical shape detection system with the positions xi, yi, zi of points Pi on the invasive device in the region of interest determined by the magnetic resonance imaging system to the actual positions of the invasive device; A method comprising: (Appendix 7) wherein the diagnostic imaging system is a magnetic resonance imaging system, and the step of measuring the positions xi, yi, zi of points Pi on the invasive device within the error margin in the region of interest comprises: - exciting by the magnetic resonance imaging system z- and / or y- and / or x-slice centered on the position xi, yi, zi of the point Pi and perpendicular to the direction vector of the invasive device; - reading out signals of the excited z-slice and / or y-slice and / or x-slice within the error margin by the magnetic resonance imaging system; - determining a location of the invasive device based on the signal; 7. The method of claim 6, comprising: (Appendix 8) 8. The method of claim 7, wherein the step of reading out signals of the magnetization in the error margin comprises reading out signals of the excited z slices and / or y slices and / or x slices with readout gradients along the x direction and / or y direction and / or z direction. (Appendix 9) 9. The method of any one of claims 7 to 8, wherein determining the position of the invasive device based on the signals comprises performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals outside of a region x-Δxi to x+Δxi and / or yi-Δyi to y+Δyi and / or z-Δzi to z+Δzi based on localization and reconstruction of the at least one point Pi on the invasive device at the position xi, yi, zi. (Appendix 10) Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals includes: - selectively exciting a z-slice and / or a y-slice and / or an x-slice; performing a selective y slice refocusing pulse at a slice center at -yi and a slice thickness of 2Δyi, and / or performing a selective x slice refocusing pulse at a slice center at xi and a slice thickness of 2Δxi, and / or performing a selective z slice refocusing pulse at a slice center at zi and a slice thickness of 2Δzi; - reading out said signals along the x-direction and / or the z-direction and / or the y-direction; 10. The method of claim 9, wherein the method is performed by a spin echo scheme having (Appendix 11) Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals includes: Exciting and spoiling the signal in the region outside -yi - Δyi to yi + Δyi and / or xi - Δxi to x + Δxi and / or zi - Δzi to zi + Δzi; - selectively exciting a z-slice and / or a y-slice and / or an x-slice; - reading out said signals along the x-direction and / or the z-direction and / or the y-direction; 10. The method of claim 9, wherein the method is performed by a saturation scheme having (Appendix 12) Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals includes: - exciting a sequence of signals along the x-direction and / or the y-direction and / or the z-direction by means of a 2d pulse centered on a point Pi of said positions xi, yi, zi; 10. The method of claim 9, wherein the method is performed by a 2d excitation scheme having (Appendix 13) Locating and reconstructing at least one point Pi on the invasive device at a position xi, yi, zi by the optical shape sensing system comprises: - locating and reconstructing at least one point Pi on the invasive device, the invasive device having at least one MR marker along its extension. 13. The method of any one of claims 6 to 12, comprising: (Appendix 14) 14. The method of any one of claims 6 to 13, wherein locating and reconstructing at least one point Pi on the invasive device at a position xi, yi, zi by the optical shape detection system comprises locating and reconstructing a point Pi at a tip point of the invasive device and / or at least one point Pi along a shaft of the invasive device. (Appendix 15) 14. The method of any one of claims 5 to 13, wherein when the step of exciting magnetization within the error margin in the region of interest is performed in a first spatial direction by the magnetic resonance imaging system, the method comprises the step of exciting magnetization within the error margin in the region of interest in at least another spatial direction. (Appendix 16) 16. A computer program comprising instructions that, when said computer program is run by a computer, cause a computer to carry out the steps of the method according to any one of claims 6 to 15. [Explanation of symbols]

[0052] invasive device 1 Excitation slices by magnetic resonance imaging system 2 Area of ​​Interest 3 Points Pi Pi at positions xi, yi, zi Direction vector of the invasive device ni spatial direction x, y, z Errors around point Pi: 2Δxi, 2Δyi, 2Δzi

Claims

1. 1. A device for determining the location of an invasive device, comprising: at least one invasive device; at least one optical shape detection system configured to determine the position and / or shape of the invasive device, the optical shape detection system further configured to locate and reconstruct at least one point Pi on the invasive device at a position xi, yi, zi with some error margin in a region of interest; a diagnostic imaging system configured to measure positions xi, yi, zi of points Pi on the invasive device within the error margin in the region of interest in at least one spatial direction; at least one computing system configured to correct the positions xi, yi, zi of points Pi on the invasive device determined by the optical shape detection system to actual positions of the invasive device using the positions xi, yi, zi of points Pi on the invasive device measured by the diagnostic imaging system; and and the diagnostic imaging system is a magnetic resonance imaging system; the magnetic resonance imaging system is further configured to excite magnetization within the error margin in the region of interest in at least one spatial direction by exciting z- and / or y- and / or x-slices centered on a point Pi at the positions xi, yi, zi and perpendicular to a direction vector of the invasive device by the magnetic resonance imaging system, the magnetic resonance imaging system is configured to read out signals of the excited z- and / or y- and / or x-slices with readout gradients along the x- and / or y- and / or z-directions, and the magnetic resonance imaging system is further configured to implement a scheme for suppressing signals of the excited z- and / or y- and / or x-slices outside a region xi−Δxi to xi+Δxi and / or yi−Δyi to yi+Δyi and / or zi−Δzi to zi+Δzi prior to the readout of the signals of the excited z- and / or y- and / or x-slices.

2. The apparatus of claim 1 , wherein the diagnostic imaging system is a magnetic resonance imaging system and the invasive device has at least one MR marker along an extension of the invasive device.

3. The device of claim 2 , wherein the MR marker is selected from the list of MR markers: paramagnetic agents, ferromagnetic agents, ferrimagnetic agents, antiferromagnetic agents, resonant pick-up RF coils, inductively coupled RF coils.

4. 1. A method for determining a position of an invasive device, the method comprising: - detecting the position and / or shape of an invasive device by means of an optical shape detection system, locating and reconstructing at least one point Pi on said invasive device at a position xi, yi, zi with some error margin in the region of interest; - measuring by a diagnostic imaging system the positions xi, yi, zi of points Pi on the invasive device within the error margin in at least one spatial direction in the region of interest; - correcting, by a computing system, the positions xi, yi, zi of points Pi on the invasive device in the region of interest determined by the optical shape detection system with the positions xi, yi, zi of points Pi on the invasive device in the region of interest measured by the diagnostic imaging system to the actual positions of the invasive device; and the diagnostic imaging system is a magnetic resonance imaging system; the measuring step exciting, with the magnetic resonance imaging system, magnetization within the error margin in the region of interest in at least one spatial direction by exciting z- and / or y- and / or x-slice centered at a point Pi at the location xi, yi, zi and perpendicular to a direction vector of the invasive device; reading out signals of the excited z- and / or y- and / or x-slices with readout gradients along the x- and / or y- and / or z-directions by the magnetic resonance imaging system; prior to the readout of the signals of the excited z- and / or y- and / or x-slices, implementing by the magnetic resonance imaging system a scheme for suppressing signals of the excited z- and / or y- and / or x-slices outside a region xi-Δxi to xi+Δxi and / or yi-Δyi to yi+Δyi and / or zi-Δzi to zi+Δzi, A method comprising:

5. wherein the diagnostic imaging system is a magnetic resonance imaging system, and the step of measuring the positions xi, yi, zi of points Pi on the invasive device within the error margin in the region of interest comprises: - exciting by the diagnostic imaging system z- and / or y- and / or x-slice centered on the position xi, yi, zi of said point Pi and perpendicular to the direction vector of the invasive device; - reading out signals of the excited z-slice and / or y-slice and / or x-slice within the error margin by the diagnostic imaging system; - determining a location of the invasive device based on the signal; 5. The method of claim 4, comprising:

6. 6. The method of claim 5, wherein the step of reading out signals of the excited z slices and / or y slices and / or x slices comprises the step of reading out signals of the excited z slices and / or y slices and / or x slices with readout gradients along x direction and / or y direction and / or z direction.

7. 7. The method according to claim 5 or 6, wherein determining the position of the invasive device based on the signals comprises performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals outside a region xi-Δxi to xi+Δxi and / or yi-Δyi to yi+Δyi and / or zi-Δzi to zi+Δzi based on localization and reconstruction of the at least one point Pi on the invasive device at the position xi, yi, zi.

8. Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals comprises: - selectively exciting a z-slice and / or a y-slice and / or an x-slice; performing a selective y slice refocusing pulse at a slice center at -yi and a slice thickness of 2Δyi, and / or performing a selective x slice refocusing pulse at a slice center at xi and a slice thickness of 2Δxi, and / or performing a selective z slice refocusing pulse at a slice center at zi and a slice thickness of 2Δzi; - reading out said signals along the x-direction and / or the z-direction and / or the y-direction; The method of claim 7, wherein the method is performed by a spin echo scheme having:

9. Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals comprises: Exciting and spoiling the signal in the region outside -yi - Δyi to yi + Δyi and / or xi - Δxi to x + Δxi and / or zi - Δzi to zi + Δzi; - selectively exciting a z-slice and / or a y-slice and / or an x-slice; - reading out said signals along the x-direction and / or the z-direction and / or the y-direction; The method of claim 7, wherein the method is performed by a saturation scheme having:

10. Implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals comprises: - exciting a sequence of signals along the x-direction and / or the y-direction and / or the z-direction by means of a 2d pulse centered on a point Pi of said positions xi, yi, zi; The method of claim 7 is performed by a 2d excitation scheme having:

11. Locating and reconstructing at least one point Pi on the invasive device at a position xi, yi, zi by the optical shape sensing system comprises: - locating and reconstructing at least one point Pi on the invasive device, the invasive device having at least one MR marker along its extension, 11. The method according to claim 4, comprising:

12. 12. The method of claim 4, wherein locating and reconstructing by the optical shape detection system at least one point Pi on the invasive device at a position xi, yi, zi comprises locating and reconstructing a point Pi at a tip point of the invasive device and / or at least one point Pi along a shaft of the invasive device.

13. 12. The method according to claim 4, wherein when the step of exciting magnetization within the error margin in the region of interest is performed in a first spatial direction by the magnetic resonance imaging system, the method comprises the step of exciting magnetization within the error margin in the region of interest in at least another spatial direction.

14. A computer program causing a computer to carry out the steps of the method according to any one of claims 4 to 13.

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