Apparatus and method for determining the position of an invasive device

Abstract

For the field of determining the location of an invasive device (1), a solution for improving the positioning of the invasive device (1) is specified. This is achieved by means of an apparatus and method for determining the location of the invasive device (1), wherein an optical shape sensing system for sensing the location and / or shape of the invasive device (1) is provided, wherein the system is arranged with a certain error tolerance (2Δx). i ,2Δy i ,2Δz i Locate position x on the invasive device (1) within the region of interest (3). i ,y i ,z i At least one point P i The optical shape sensing system, with a certain error tolerance (2Δx) i ,2Δy i ,2Δz i Locate and reconstruct the position x on the invasive device (1) within the region of interest (3). i ,y i ,z i At least one point P i An MRI system is also provided, which is used by the MRI system in the error tolerance (2Δx) i ,2Δy i ,2Δz i The point P on the invasive device (1) is measured in at least one spatial direction (x, y, z). i The position x in the region of interest (3) i ,y i ,z i The MRI system reads the values ​​within the error tolerance (2Δx). i ,2Δy i ,2Δz i The magnetized signal within the region of interest (3) is used to determine the position of the invasive device (1). The point P on the invasive device (1) within the region of interest (3) is determined by the optical shape sensing system. i The position x i ,y i ,z i The correction system utilizes the point P on the invasive device (1) within the region of interest (3) determined by the MRI system. i The position x i ,y i ,z i Corrected to point P on the invasive device (1) i The actual location.

Description

Technical Field

[0001] This invention relates to the field of determining the location of invasive devices, and more particularly to the field of determining the location of invasive devices based on optical shape sensing supported by diagnostic imaging. Background Technology

[0002] In many applications, MRI guidance for intravascular procedures is a promising approach because it offers superior soft tissue contrast compared to conventional fluoroscopy or ultrasound guidance. While various contrast and physiological parameters are significant advantages in MRI, unlike fluoroscopy or ultrasound, visualization and localization of invasive devices such as catheters are associated with additional technical effort and safety concerns. MRI devices can be passively visualized through contrast caused by the absence of water in the invasive device, through contrast caused by the presence of contrast agents in the invasive device, or actively visualized by integrating a wired μ-MR receiver coil into the invasive device.

[0003] Fiber shape sensing allows for the sensing of the shape of flexible composite fibers in a 3D manner with high temporal and spatial resolution. It is based on the optical sensing of strain along the individual optical cores of the composite fiber via fiber Bragg gratings or Rayleigh scattering. The known relative configuration of the cores allows for the reconstruction of the composite fiber's shape from the strain data.

[0004] Passive MR visualization requires the invasive device to be contained within a real-time MR imaging slice to be visible. Therefore, both the invasive device and the imaging slice must be manipulated sequentially, which is obviously less quick and straightforward than visualization in fluoroscopy. The imaging slice must be shifted and angled to depict at least a portion of the invasive device's axis. In most cases, 3D invasive device configurations allow visualization of only a short portion of the axis within a single slice. For these reasons, passive visualization is rarely used with invasive devices, and more precisely, with rigid devices such as needles and ablation devices.

[0005] Active MR tracking was demonstrated preclinically over a decade ago, but its clinical application has been limited for a long time due to safety concerns surrounding the wiring of the μ-coils within the invasive device, caused by potential RF heating of the device during MR imaging. This issue has been addressed by incorporating miniature transformers into the wiring. However, in practice, active invasive device tracking can only locate two or at most three points along the invasive device. This is because each point must be equipped with a μ-coil, requiring a separate cable approximately 500 μm in diameter within the invasive device's axis. This is a major drawback compared to competing methods for invasive device visualization in other modalities, including electromagnetic positioning systems that truly display at least a large portion of the entire or distal axis of the invasive device. Furthermore, even the latest implementations of active MR tracking technology still exhibit a relatively high failure rate due to breakage of the internal wiring, primarily caused by repeated sharp bending of the invasive device.

[0006] Fiber True Shape Reconstruction (FORS) technology is based on measuring the mechanical strain at numerous points along the fiber and reconstructing the shape by integrating these strain values. Therefore, the errors in individual strain measurements are additive, causing the shape error to increase from zero at a known fixed point near the fiber end towards the fiber end. Current implementations of FORS technology achieve an end-position accuracy (distance to the true position) of 6 mm on a 1.8 m fiber. The majority of this error is caused by the systematic effect of tension on the fiber. The accuracy (standard deviation of repeated measurements in a fixed fiber configuration) is approximately 1 mm at 50 Hz, which is relatively small. However, a total end-position accuracy of 6 mm remains too high for many invasive devices or catheter applications, particularly for cardiac catheter ablation performed using catheters with diameters between 1.3 mm and 2 mm.

[0007] US Patent Application US2014 / 155737 relates to bending multiplanar mapping (MPR) based on 3D reconstructed MR image data of the shape of a catheter measured by fiber optic shape (FOS) sensing. Summary of the Invention

[0008] The object of the present invention is to provide an apparatus and method for determining the position of an invasive device based on optical shape sensing supported by diagnostic imaging (e.g., magnetic resonance imaging), such that the accuracy of determining the position by optical shape sensing is improved.

[0009] According to the invention, this objective is achieved through the subject matter of the independent claims. Preferred embodiments of the invention are described in the dependent claims.

[0010] Therefore, according to the present invention, an apparatus for determining the location of an invasive device is provided, the apparatus comprising: at least one invasive device; at least one optical shape sensing system; wherein the optical shape sensing system is configured to determine the location and / or shape of the invasive device, and the optical shape sensing system is further arranged to locate and reconstruct the location x on the invasive device within a region of interest with a certain error tolerance. i ,y i ,z i At least one point P i A diagnostic imaging system (e.g., a magnetic resonance imaging (MRI) system), wherein the MRI system is configured to measure point P on the invasive device within the region of interest and in at least one spatial direction, within the error tolerance. i The position x i ,y i ,z i At least one computing system, wherein the computing system is configured to access the point P on the invasive device determined by the MRI system. i The position x i ,y i ,z i To determine the point P on the invasive device by the optical shape sensing system i The position x i ,y i ,z i The correction is made to the actual position of the invasive device.

[0011] The basic concept of this invention is the integration of FORS technology with a diagnostic imaging system (such as an MRI system), and the enhancement of FORS data through dedicated MR imaging, such that the accuracy of shape sensing along the entire invasive device is improved to a fraction of the diameter of the invasive device. FORS is used to locate isolated and predefined points P on the invasive device in a 3D manner. i Dedicated MR projection and imaging sequences were used to cover these regions of interest with high resolution but a very limited field of view and therefore a very short acquisition time. Dedicated reconstructions of these MR data resolved the precise locations of the points, which were then used to correct for overall shape reconstruction.

[0012] According to a preferred embodiment, the magnetic resonance imaging (MRI) system is further configured to excite at the location x using the MRI system. i ,y i ,z i The point P at that location iMagnetization is performed in at least one spatial direction within the region of interest, centered on and perpendicular to the direction vector, of z-slices and / or y-slices and / or x-slices with the error tolerance described above. The MRI system is configured to read out the signals of the 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. The MRI system is also configured to perform a signal suppression scheme for finding the signals of the excited z-slices and / or y-slices and / or x-slices to determine a point P on the invasive device based on the signals. i Position x i ,y i ,z i .

[0013] According to another preferred embodiment, the invasive device includes at least one MR marker along an extension of the invasive device. This simplifies the extraction of point P on the invasive device from MR data. i The invasive device can be located at point P. i The location is equipped with MR markers.

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

[0015] In another aspect of the invention, this objective is achieved by a method for determining the location of an invasive device, the method comprising the following steps:

[0016] Provide invasive equipment,

[0017] Provides magnetic resonance imaging (MRI) systems.

[0018] An optical shape sensing system is provided for sensing the position and / or shape of the invasive device, the system being arranged to locate the position x on the invasive device within a region of interest with a certain error tolerance. i ,y i ,z i At least one point P i ,

[0019] The optical shape sensing system locates and reconstructs the position x on the invasive device within the region of interest. i ,y i ,z i At least one point P i ,

[0020] The point P on the invasive device is measured by the MRI system in at least one spatial direction within the error tolerance of the region of interest. i The position x i ,y i ,z i ,

[0021] The magnetized signal, within the error tolerance, is read out by the MRI system.

[0022] The location of the invasive device (1) is determined based on the signal.

[0023] The correction system utilizes the point P on the invasive device within the region of interest, determined by the MRI system. i The position x i ,y i ,z i To correct the point P on the invasive device in the region of interest determined by the optical shape sensing system. i The position x i ,y i ,z i .

[0024] In short, the present invention relates to determining the location of an invasive device based on a combination of (i) optical shape sensing and (ii) diagnostic imaging (particularly magnetic resonance imaging, X-ray imaging, or computed tomography). According to the invention, a relatively inaccurate determination of the location of the invasive device is made by optical shape sensing, and then this initial location is used to arrange radio frequency (RF) excitation of a finite volume (thick slice) around the initial location, and a more accurate determination of the location of the invasive device within the thick slice is derived from MR image information of the thick slice excited by the RF. In a particular embodiment, this is accomplished by projecting magnetic resonance signals from the thick slice in three directions (which returns to the location of the invasive device within the thick slice). This determination utilizes the fact that the MR response of the material of the invasive device differs from that of the surrounding (tissue, primarily water) within the thick slice.

[0025] This method involves the operation of the technical equipment described above, specifically how the location of an invasive device is determined by a computer with the aid of an optical shape sensing system and a magnetic resonance imaging (MRI) system. Using this method, the location 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 with respect to the invasive device and the surgical procedure produced on the body by the device. Therefore, this method and the effects produced on a human or animal body by the device are simply not suitable as a method for treatment. Furthermore, this method does not include procedural steps for surgical treatment of the body, nor does it involve any such steps. In particular, this method does not include or includes invasive steps representing substantial physical intervention on the body, invasive steps requiring specialized medical expertise, and invasive steps involving substantial health risks even when performed with the required specialized care and expertise. Specifically, it can be provided that this method is not applicable to human or animal bodies.

[0026] According to a preferred embodiment, the point P on the invasive device is measured within the error tolerance in the region of interest. i The position x i ,y i ,z i The steps include the following:

[0027] Using the MRI system to excite at the location x of the invasive device i ,y i ,z i The point P at that location i Centered on the z-slice and / or y-slice and / or x-slice perpendicular to the direction vector,

[0028] The MRI system reads out the signals from the excited z-slices and / or y-slices and / or x-slices within the error tolerance.

[0029] The location of the invasive device is determined based on the signal.

[0030] Preferably, the step of reading out the magnetized signal within the error tolerance includes the step of reading out the signal of the excited z-slice and / or y-slice and / or x-slice using a readout gradient along the x-direction and / or along the y-direction and / or along the z-direction.

[0031] More preferably, the thickness of the z-slice and / or y-slice and / or x-slice is between two and three times the thickness of the invasive device.

[0032] Preferably, the step of determining the position of the invasive device based on the signal includes the optical shape sensing system determining the position x on the invasive device based on the position x.i ,y i ,z i At least one point P at the location i The aforementioned positioning and reconstruction are used to perform operations on the region x. i -Δx i To x i +Δx i and / or y i -Δy i to y i +Δy i and / or z i -Δz i To z i +Δz i The steps of a scheme to suppress signals from z-slices and / or y-slices and / or x-slices that are excited outside of the signal.

[0033] According to another preferred embodiment, the step of implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice signals is performed by a spin echo scheme including the following steps:

[0034] Selectively excite z-slices and / or y-slices and / or x-slices.

[0035] In slices with y i Centered on and sliced ​​with a thickness of 2Δy i Perform selective y-slice refocusing pulses in the case of slices, and / or slices with x i Centered on and sliced ​​with a thickness of 2Δx i Perform selective x-slice refocusing pulses in the case of slices, and / or perform z-slice refocusing pulses in the case of slices. i Centered on and sliced ​​with a thickness of 2Δz i In the case of performing selective z-slice refocusing pulse,

[0036] The signal is read out along the x and / or z and / or y directions.

[0037] Preferably, the step of performing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice is performed by a saturation scheme including the following steps:

[0038] Excite and destroy in y i -Δy i To y i +Δy i and / or x i -Δx i To x i +Δx i and / or z i -Δz i To zi +Δz i Signals outside the area,

[0039] Selectively excite z-slices and / or y-slices and / or x-slices.

[0040] The signal is read out along the x and / or z and / or y directions.

[0041] Preferably, the step of implementing a signal suppression scheme for finding the signals of the excited z-slice and / or y-slice and / or x-slice is performed by a 2D excitation scheme including the following steps:

[0042] By using the x i ,y i ,z i The point P at the location i A 2D pulse centered on the signal excites a series of signals along the x and / or y and / or z directions.

[0043] Preferably, the optical shape sensing system locates and reconstructs the position x on the invasive device. i ,y i ,z i At least one point P i The steps include the following:

[0044] Locate and reconstruct at least one point P on the invasive device i The invasive device includes at least one MR marker along an extension of the invasive device.

[0045] Preferably, the optical shape sensing system locates and reconstructs the position x on the invasive device. i ,y i ,z i At least one point P i The steps include locating and reconstructing point P at the end point of the invasive device. i and / or at least one point P along the axis of the invasive device i The steps.

[0046] More preferably, the position x on the invasive device is located and reconstructed. i ,y i ,z i At least one point P i The steps include the following steps: first, locating the end point of the invasive device; then, locating and reconstructing the point at half the length of the invasive device; then, locating and reconstructing the point at a quarter the length of the invasive device, and so on, as in a half-interval search.

[0047] According to an embodiment of the present invention, when the step of exciting magnetization in the region of interest with the error tolerance has been performed by the MRI system in a first spatial direction, the method includes the step of exciting magnetization in the region of interest in at least another spatial direction with the error tolerance.

[0048] In another aspect of the invention, this objective is achieved by a computer program product comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method as described above.

[0049] In another aspect of the invention, this objective is achieved by a software package for a magnetic resonance (MR) imaging system, wherein the software package contains instructions for controlling the magnetic resonance imaging (MRI) system as described above.

[0050] Other embodiments of the invention may utilize diagnostic imaging modalities, such as computed tomography or X-ray imaging. Optical shape sensing provides the device end-effector position within an error tolerance representing a 3D volume (which can be represented as V). Optical shape sensing also provides the orientation of the end-effector segment of the device, which can be represented by an orientation vector k. The following embodiments demonstrate the use of this knowledge to improve the detection of accurate end-effector positions in X-rays or CT scans.

[0051] In an embodiment of the invention based on X-ray imaging, it is proposed to project a volume V onto an X-ray image, thereby effectively creating a 2D region of interest (ROI) in the image. It is proposed to limit the area used for searching the device end to this ROI. Some additional tolerance may be added depending on the known dimensions of the device. This ensures that the ROI completely covers the outer perimeter of the device. In terms of increased sensitivity and reduced false positive rate, this simple measure already greatly improves the robustness (increased specificity) of detection at the device end.

[0052] For device detection itself, any image processing algorithm can be used to find devices within the ROI, but preferably, a known orientation vector k and the size of the device can also be used. As an example, a line filter is used to enhance any linear structure in the ROI corresponding to the projection k' of orientation k onto the image plane. After the actual line structure corresponding to the device has been identified, another filter can be used to precisely determine the ends of the line along direction k', i.e., the device ends.

[0053] In an embodiment of the invention based on computed tomography (CT), it is proposed to first use the longitudinal (z) range of volume V. The search range of the device can be limited to the corresponding z-range of the detection / reconstruction volume of CT. Secondly, similar to the embodiment in X-ray, the orientation k is known, and here the line structure along k is directly enhanced using a filter. Finally, the ends of the line along k can be searched to detect the end positions. Attached Figure Description

[0054] These and other aspects of the invention will become apparent and set forth with reference to the embodiments described below. However, such embodiments do not necessarily represent the full scope of the invention, and therefore the scope of the invention is to be determined by reference to the claims and herein.

[0055] In the attached diagram:

[0056] Figure 1 The position x of an invasive device located by an optical shape sensing system according to an embodiment of the present invention is schematically depicted. i ,y i ,z i Point P at the location i And a sketch of the excited z-slice,

[0057] Figure 2 A flowchart of a method for determining the location of an invasive device according to an embodiment of the present invention is shown.

[0058] List of reference numerals

[0059] Invasive equipment 1

[0060] Slice 2 excited by MRI system

[0061] Area of ​​Interest 3

[0062] Position x i ,y i ,z i Point P at the location i P i

[0063] The direction vector n of the invasive device i

[0064] Spatial directions x, y, z

[0065] Point P i The surrounding error tolerance 2Δx i ,2Δy i ,2Δz i Detailed Implementation

[0066] Figure 1A position x, located by an optical shape sensing system, is schematically depicted according to an embodiment of the invention. i ,y i ,z i Point P at the location i A sketch of the invasive device 1 and the stimulated z-slice 2. Point P i The FORS on invasive device 1 locates the location x i ,y i ,z i However, due to limited accuracy, the true location may be contained within x. i ,y i ,z i Error tolerance 2Δx centered i ,2Δy i ,2Δz i In this context, the error tolerance is 2Δx. i ,2Δy i ,2Δz i The size can vary from point to point and is therefore indexed, and in the absence of further prior knowledge, the size will generally increase toward the end of invasive device 1. FORS reconstruction also provides the invasive device 1 at point P. i The direction vector n at that location i In order to improve P i The accuracy of positioning in the x-direction (x) is measured by the MR scanner at point P on the invasive device 1. i Position x i ,y i ,z i In embodiments of the invention, it may be particularly provided that the MR scanner excites at x i ,y i ,z i The thickness of the invasive device 1 centered on the center is approximately two to three times that of the center and perpendicular to the direction vector n. i Slice 2, as Figure 1 As shown in the diagram. The readout of the signal in slice 2, having a readout gradient along the x-direction x, provides a projection of all signals in slice 2 integrated along the y-direction y. Since there is no water in the invasive device 1, this projection is taken at the actual position x of the device. ti A small signal reduction is expected. However, the heterogeneity of signals from body tissue throughout slice 2 will also provide signal variations, potentially masking the small signal reduction from invasive device 1. Therefore, it is proposed to perform signal reading from region y before signal readout. i -Δy i To y i +Δy iThe signal outside slice 2 is suppressed. Therefore, the projection only contains the signal integrated along the y-axis in that small region. The absence of signal in the device will now result in a significant reduction in signal in the projection. The location of this signal drop corresponds to the device's true position x. ti Due to prior knowledge from FORS measurements, the search for this signal drop only needs to be performed in region x. i -Δx i To x i +Δx i The signal suppression can be implemented through various methods.

[0067] In embodiments of the invention, signal suppression is performed using a spin echo scheme. After selective excitation of the z-slice, at the slice center in the y-slice... i The slice thickness is 2Δy. i In this case, a selective refocusing pulse is performed on the y-slice. The following readout in the x-direction x will only acquire signals from the cross-sections of the excitation z-slice 2 and the refocusing y-slice. In another embodiment, signal suppression is performed by a saturation scheme, wherein, in the y i -Δy i To y i +Δy i Signals outside the region are excited and destroyed, followed by selective excitation of z-slice 2 and readout along the x-direction.

[0068] In another embodiment of the invention, signal suppression is performed using a 2d excitation scheme. The 2d pulse is used to excite only the signal along x. i ,y i ,z i Centered on and having a width y i ,z i A sequence of signals. For illustration and ease of annotation, invasive device 1 has been oriented along... Figure 1 The z-axis in the data can be used to export the data of invasive device 1 at point P from FORS data. i The approximate orientation at the point is such that the selected slice 2 is oriented perpendicular to the row of the invasive device 1. This causes a minimal partial volume effect due to the finite width of slice 2 and pixels in the projected readout.

[0069] The above embodiments of the present invention describe the acquisition of MR projection data to improve P i Positioning in the x-direction. In embodiments of the invention, to improve positioning in both the y-direction and the z-direction, similar steps can be performed in at least another spatial direction, x, y, z.

[0070] Along the direction of invasive device 1 (in) Figure 1In the illustrated embodiment, the z-direction (z) represents a slightly different problem because the invasive device 1 does not a priori provide structures that can be visualized in MR. However, point P i It can be selected to be consistent with the structure of invasive device 1 that already provides some MR contrast. In another embodiment of the invention, point P i Passive MR markers known in the art can be incorporated 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. Alternatively, active markers, such as resonant pickup radio frequency (RF) coils or semi-active inductively coupled RF coils, can be provided. Even with only point P... i x i and y i The coordinates also improved the positioning of FORS. Due to MR measurements, point P... i The true location is available with high accuracy. Therefore, FORS reconstruction can be performed segment by segment, and only the shape between those points must be solved. Initially, MR localization of the end of the invasive device 1 results in the greatest gain of information about the FORS reconstruction. In an embodiment, it may be intended to first use MR localization of the end points of the invasive device 1, and continue with points at half the length of the invasive device 1, then continue with points at a quarter the length of the invasive device 1, and so on, as in a half-interval search.

[0071] Figure 2 A flowchart illustrating a method for determining the location of an invasive device 1 according to an embodiment of the present invention is shown. The method begins at 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 location and / or shape of the invasive device 1. Optical shape sensing, or fiber optic shape sensing, allows sensing the shape of a flexible composite optical fiber in a 3D manner with high temporal and spatial resolution. It is based on optical sensing of strain along the individual optical cores of the composite optical fiber via fiber Bragg gratings or via Rayleigh scattering. The known relative configuration of the cores allows the shape of the composite optical fiber to be reconstructed from the strain data.

[0072] In step 210, position x on invasive device 1 i ,y i ,z i At least one point P i The optical shape sensing system has a certain error tolerance of 2Δx i ,2Δy i ,2Δz i Locate and reconstruct within region of interest 3.

[0073] In step 220, the MRI system uses an error tolerance of 2Δxi ,2Δy i ,2Δz i Magnetization is excited in at least one spatial direction (x, y, z) within the region of interest 3. In embodiments of the invention, the magnetization can be excited at position x using an MRI system. i ,y i ,z i Point P at the location i The direction vector n centered on and perpendicular to invasive device 1 i 2. z-slices and / or y-slices and / or x-slices. To improve P i For example, the accuracy of positioning in the x-direction, the MR scanner excitation with x i ,y i ,z i The thickness of the invasive device 1 centered on the center is approximately two to three times that of the center and perpendicular to the direction vector n. i Slice 2. Therefore, in embodiments of the present invention, it is foreseeable that invasive device 1 can be derived from FORS data at point P. i The approximate orientation at the location is determined, and the selected slice 2 is oriented perpendicular to the invasive device 1. This results in a minimal partial volume effect caused by the finite width of the slice and pixel in the projected readout.

[0074] In step 230, the MRI system reads the data with an error tolerance of 2Δx. i ,2Δy i ,2Δz i The magnetized signal. In an embodiment of the invention, the MRI system reads out signals from an excited z-slice and / or y-slice and / or x-slice 2 having readout gradients along the x-direction x and / or along the y-direction y and / or along the z-direction z. For example, the readout of the signal from slice 2 having a readout gradient along the x-direction x provides a projection of all signals in slice 2 integral along the y-direction y. Since there is no water in the device, the projection is at the actual location x of the device. ti A small signal reduction is expected. However, the heterogeneity of signals from body tissue throughout the slice will also provide signal variations, potentially masking the small signal reduction from the device. Therefore, it is proposed to perform signal readings from region y before signal readout. i -Δy i To y i +Δy i The signal from slice 2 outside of this area is suppressed. Therefore, the projection contains only the signal integrated along the y-axis within this small region. The absence of a signal in the device will now result in a significant reduction in the signal in the projection. The location of this signal drop corresponds to the actual location x of the invasive device 1. ti Due to prior knowledge from FORS measurements, the search for this signal drop only needs to be performed in region x. i-Δx i To x i +Δx i The process is performed within the specified timeframe. Therefore, in another embodiment of the invention, the step of determining the position of the invasive device 1 based on a signal includes the optical shape sensing system determining the position x based on the signal. i ,y i ,z i At least one point P on the invasive device 1 at the site i The location and reconstruction are performed for the purpose of positioning and reconstruction in region x i -Δx i To x i +Δx i and / or y i -Δy i To y i +Δy i and / or z i -Δz i To z i +Δz i The steps of a scheme to suppress signals from the z-slice and / or y-slice and / or x-slice 2 that are excited outside of the signal.

[0075] Signal suppression can be performed using various schemes. For example, the steps of implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice 2 are performed by a spin echo scheme including the following steps:

[0076] Selectively excite z-slices and / or y-slices and / or x-slices 2.

[0077] At the center of the slice at y i The slice thickness is 2Δy. i In the case of performing selective y-slice refocusing pulses, and / or at the slice center in x i The slice thickness is 2Δx. i In the case of performing selective x-slice refocusing pulses, and / or at the center of the slice in the z-slice... i The slice thickness is 2Δz. i In the case of performing selective z-slice refocusing pulse,

[0078] Read out the signal along the x-direction and / or z-direction and / or y-direction.

[0079] In another 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 is performed by a saturation scheme including the following steps:

[0080] Excite and destroy in y i -Δy i To y i+Δy i and / or x i -Δx i To x i +Δx i and / or z i -Δz i To z i +Δz i Signals outside the area.

[0081] Selectively excite z-slices and / or y-slices and / or x-slices 2.

[0082] Read out the signal along the x-direction and / or z-direction and / or y-direction.

[0083] In another embodiment of the invention, the step of performing a scheme for signal suppression of the signals of the excited z-slice and / or y-slice and / or x-slice 2 is performed by a 2D excitation scheme including the following steps:

[0084] By using x i ,y i ,z i Point P at location i A 2D pulse centered on the signal excites a series of signals along the x and / or y and / or z directions.

[0085] The measurement data obtained in this way is then used to determine the location of the invasive device 1 based on the signal.

[0086] In step 240, point P on the invasive device 1 is determined by the optical shape sensing system. i Position x in region of interest 3 i ,y i ,z i The correction system utilizes point P on the invasive device 1 within the region of interest 3, as determined by the MRI system. i Position x i ,y i ,z i Correct to the actual position of invasive device 1.

[0087] Although the invention has been illustrated and described in detail in the accompanying drawings and the foregoing description, such illustrations and descriptions should be considered illustrative or exemplary, not restrictive; the invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and implemented by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure, and the claims. In the claims, the word "comprising" does not exclude other elements or steps, and the words "a" or "an" do not exclude a plurality. Although specific measures are recited in mutually different dependent claims, this does not indicate that combinations of these measures cannot be advantageously used. Any reference numerals in the claims should not be construed as limiting the scope. Furthermore, for clarity, not all elements in the drawings are provided with reference numerals.

Claims

1. An apparatus for determining the location of an invasive device, the apparatus comprising: At least one invasive device (1). At least one optical shape sensing system, wherein the optical shape sensing system is configured to determine the position and / or shape of the invasive device (1), and the optical shape sensing system is further arranged to have a certain error tolerance (2Δx). i ,2Δy i , 2Δz i Locate and reconstruct the position x on the invasive device (1) within the region of interest (3). i , y i , z i At least one point P i , A diagnostic imaging system, wherein the diagnostic imaging system is configured to operate at least in one spatial direction (x, y, z) within the error tolerance (2Δx). i , 2Δy i , 2Δz i The point P on the invasive device (1) is measured within the region of interest (3). i The position x i , y i , z i , At least one computing system, wherein the computing system is configured to access the point P on the invasive device determined by the diagnostic imaging system. i The position x i , y i , z i The point P on the invasive device determined by the optical shape sensing system i The position x i , y i , z i The position is corrected to the actual position of the invasive device (1).

2. The apparatus according to claim 1, wherein, The diagnostic imaging system is a magnetic resonance imaging system, a computed tomography imaging system, or an X-ray imaging system.

3. The apparatus according to claim 1, wherein, The diagnostic imaging system is a magnetic resonance imaging (MRI) system, which is further configured to excite at the location x using the MRI system. i , y i ,z i The point P at that location i Centered on and perpendicular to the direction vector (n), z slices and / or y slices and / or x slices (2) with the error tolerance (2Δx) i , 2Δy i , 2Δz i The magnetic resonance imaging system is configured to read out the signals of the excited z-slice and / or y-slice and / or x-slice (2) using readout gradients along the x-direction (x) and / or along the y-direction (y) and / or along the z-direction (z). The magnetic resonance imaging system is also configured to perform a scheme for finding signal suppression in the signals of the excited z-slice and / or y-slice and / or x-slice (2) to determine the point P on the invasive device (1) based on the signals. i Position x i ,y i , z i .

4. The apparatus according to any one of claims 1 to 3, wherein, The diagnostic imaging system is a magnetic resonance imaging system, and the invasive device (1) includes at least one MR marker along an extension of the invasive device (1).

5. The apparatus according to claim 4, wherein, The MR markers are selected from the following list of MR markers: paramagnetic agents, ferromagnetic agents, ferrimagnetic agents, antiferromagnetic agents, resonant pickup radio frequency (RF) coils, and inductively coupled RF coils.

6. A method for determining the location of an invasive device (1), the method comprising the steps of: Provide invasive equipment (1). Provide diagnostic imaging systems, An optical shape sensing system is provided for sensing the position and / or shape of the invasive device (1), the optical shape sensing system being arranged with a certain error tolerance (2Δx). i , 2Δy i , 2Δz i Locate the position x on the invasive device (1) within the region of interest (3). i , y i , z i At least one point P i , The optical shape sensing system locates and reconstructs the position x on the invasive device (1) within the region of interest (3). i , y i , z i At least one point P i , The diagnostic imaging system, at least in one spatial direction (x, y, z), within the error tolerance (2Δx) i , 2Δy i , 2Δz i The point P on the invasive device (1) is measured within the region of interest (3). i The position x i ,y i , z i , The point P on the invasive device (1) in the region of interest (3) is determined by the diagnostic imaging system and utilized by the computing system. i The position x i , y i , z i The point P on the invasive device (1) in the region of interest (3) determined by the optical shape sensing system. i The position x i , y i , z i The position is corrected to the actual position of the invasive device (1).

7. The method according to claim 6, wherein, The diagnostic imaging system is a magnetic resonance imaging system, and within the error tolerance (2Δx) i , 2Δy i , 2Δz i The point P on the invasive device (1) is measured within the region of interest (3). i The position x i , y i , z i The steps include the following: The diagnostic imaging system is used to excite the point P. i The position x i , y i , z i The direction vector (n) centered on and perpendicular to the invasive device (1) i (2) z slices and / or y slices and / or x slices. The diagnostic imaging system is within the error tolerance (2Δx) i , 2Δy i , 2Δz i The signals from the excited z-slice and / or y-slice and / or x-slice (2) are read out within the cell. The location of the invasive device (1) is determined based on the signal.

8. The method according to claim 7, wherein, Within the error tolerance (2Δx) i , 2Δy i , 2Δz i The step of reading out the magnetized signal includes the step of reading out the signal of the excited z slice and / or y slice and / or x slice (2) by means of the readout gradient along the x direction and / or along the y direction and / or along the z direction (x, y, z).

9. The method according to claim 7 or 8, wherein, The step of determining the position of the invasive device (1) based on the signal includes the optical shape sensing system determining the position x on the invasive device (1) based on the position x. i , y i , z i At least one point P at the location i The aforementioned positioning and reconstruction are used to perform operations on the region x. i -Δx i To x i +Δx i and / or y i -Δy i To y i +Δy i and / or z i -Δz i To z i + Δz i The steps of the scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice (2) other than the signal of the z-slice and / or y-slice and / or x-slice (2).

10. The method according to claim 9, wherein, The steps of implementing a scheme for signal suppression of the signals of the excited z-slice and / or y-slice and / or x-slice (2) are performed by a spin echo scheme including the following steps: Selectively excite z-slices and / or y-slices and / or x-slices (2). At the center of the slice at y i The slice thickness is 2Δy. i In the case of performing selective y-slice refocusing pulses, and / or at the slice center in x i The slice thickness is 2Δx. i In the case of performing selective x-slice refocusing pulses, and / or at the center of the slice in the z-slice... i The slice thickness is 2Δz. i In the case of performing selective z-slice refocusing pulse, The signal is read out along the x-direction (x) and / or z-direction (z) and / or y-direction (y).

11. The method according to claim 9, wherein, The steps of implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice (2) are performed by a saturation scheme comprising the following steps: Excite and destroy in y i -Δy i To y i +Δy i and / or x i -Δx i To x i +Δx i and / or z i -Δz i To z i +Δz i Signals outside the area, Selectively excite z-slices and / or y-slices and / or x-slices (2). The signal is read out along the x-direction (x) and / or z-direction (z) and / or y-direction (y).

12. The method according to claim 9, wherein, The steps of implementing a scheme for signal suppression of the excited z-slice and / or y-slice and / or x-slice (2) are performed by a 2D excitation scheme including the following steps: By using the position x i , y i , z i The point P at that location i A 2d pulse centered on the signal excites a series of signals along the x-direction (x) and / or y-direction (y) and / or z-direction (z).

13. The method according to any one of claims 6 to 8, wherein, The optical shape sensing system locates and reconstructs the position x on the invasive device. i , y i , z i At least one point P i The steps include the following: Locate and reconstruct at least one point P on the invasive device (1). i The invasive device includes at least one MR marker along an extension of the invasive device (1).

14. The method according to any one of claims 6 to 8, wherein, The optical shape sensing system locates and reconstructs the position x on the invasive device. i , y i , z i At least one point P i The steps include locating and reconstructing point P at the end point of the invasive device (1). i and / or at least one point P along the axis of the invasive device (1) i The steps.

15. The method according to any one of claims 6 to 8, wherein, When the aforementioned error tolerance (2Δx) is used i , 2Δy i , 2Δz i When the step of exciting magnetization in the region of interest (3) has been performed by the magnetic resonance imaging system in the first spatial direction (x, y, z), the method includes, in at least another spatial direction (x, y, z), at the error tolerance (2Δx) i , 2Δy i , 2Δz i The step of exciting magnetization in the region of interest (3).

16. A computer program product including instructions, wherein when the program is executed by a computer including a calibration system, the instructions cause the computer to perform the following steps: The position and / or shape of the invasive device (1) are sensed by an optical shape sensing system, the system being arranged with a certain error tolerance (2Δx). i , 2Δy i , 2Δz i Locate the position x on the invasive device (1) within the region of interest (3). i ,y i , z i At least one point P i , The optical shape sensing system locates and reconstructs position x in the region of interest (3). i , y i , z i At least one point P on the invasive device (1) at the location i , The diagnostic imaging system, at least in one spatial direction (x, y, z), within the error tolerance (2Δx) i , 2Δy i , 2Δz i The point P on the invasive device (1) is measured within the region of interest (3). i The position x i , y i ,z i , The point P on the invasive device (1) in the region of interest (3) is determined by the diagnostic imaging system and utilized by the computing system. i The position x i , y i , z i The point P on the invasive device (1) in the region of interest (3) determined by the optical shape sensing system. i The position x i , y i , z i The correction is made to the actual position of the invasive device (1), and optionally, the steps of the method according to any one of claims 7 to 15.

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