Magnetic resonance three-dimensional temperature monitoring device and system

Abstract

The invention provides a magnetic resonance three-dimensional temperature monitoring device and system. The device comprises a host and a display device. An executable instruction is stored in the host, and when the executable instruction is executed by the host, a continuous magnetic resonance image covering a target area is obtained through fast magnetic resonance imaging; generating a three-dimensional temperature map according to the continuous magnetic resonance images; and fusing and displaying the three-dimensional temperature diagram and a preoperative three-dimensional image. The continuous magnetic resonance image covering the target area is efficiently obtained through rapid magnetic resonance imaging and used for establishing the three-dimensional temperature diagram, three-dimensional temperature data are obtained, temperature monitoring is more comprehensive, and evaluation of the ablation state is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a magnetic resonance three-dimensional temperature monitoring device and system. Background Art

[0002] Laser interstitial thermotherapy (LITT) is a treatment method that introduces laser into human tissue through an optical fiber and uses the thermal effect of the laser to destroy the target tissue. In order to accurately ablate the target tissue, real-time temperature monitoring of the target tissue and its surrounding tissues is required. To meet the real-time requirement, the current main method of temperature monitoring is to use a magnetic resonance device to collect and generate temperature maps at several parallel cross-sections passing through the target tissue. This temperature monitoring method can only view temperature data on some cross-sections, making it difficult to monitor temperature data in other regions, and there is a high risk of damaging normal tissues. It is also difficult to accurately evaluate the ablation effect during ablation assessment.

[0003] In view of the above disadvantages of the prior art, the present invention proposes a magnetic resonance three-dimensional temperature monitoring device, system and method. Summary of the Invention

[0004] The present invention provides a magnetic resonance three-dimensional temperature monitoring device, system and method to solve the defects in the prior art and more comprehensively and accurately monitor temperature data while meeting the real-time requirement.

[0005] The present invention provides a magnetic resonance three-dimensional temperature monitoring device, characterized by comprising: a host and a display device; the host stores executable instructions, and when the executable instructions are executed by the host, the following functions are realized:

[0006] Obtaining continuous magnetic resonance images covering the target area through fast magnetic resonance imaging;

[0007] Generating a three-dimensional temperature map based on the continuous magnetic resonance images;

[0008] Fusing and displaying the three-dimensional temperature map with the preoperative three-dimensional image.

[0009] According to the magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the step of obtaining continuous magnetic resonance images covering the target area through fast magnetic resonance imaging includes:

[0010] Determining a target area to be sampled in the current period according to a preset magnetic resonance downsampling rule;

[0011] Performing magnetic resonance scanning on the target area to obtain a magnetic resonance image of the target area;

[0012] Based on the magnetic resonance image of the target area, continuous magnetic resonance images covering the target area in the current period are obtained through a reconstruction algorithm.

[0013] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the preset magnetic resonance downsampling rule is inter-slice downsampling and / or intra-slice downsampling.

[0014] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the obtaining of the continuous magnetic resonance images covering the target area in the current period based on the magnetic resonance imaging sequence of the target area through a reconstruction algorithm includes:

[0015] Based on the magnetic resonance image of the target area, continuous magnetic resonance images covering the target area are obtained by interpolation; or,

[0016] Based on the magnetic resonance image of the target area, interpolation is performed in combination with the magnetic resonance image of its complementary period to obtain the continuous magnetic resonance images covering the target area.

[0017] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the obtaining of the continuous magnetic resonance images covering the target area through fast magnetic resonance imaging includes:

[0018] Periodically scan the target area through a magnetic resonance fast imaging sequence;

[0019] Use the reference period to correct the magnetic resonance image of the current period to obtain a corrected magnetic resonance image for generating the three-dimensional temperature map of the current period.

[0020] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the reference period is the scanned image of the positioning sequence obtained by pre-scanning a reference area, and the reference area covers the target area.

[0021] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the magnetic resonance fast sequence is a gradient echo sequence, and the positioning sequence is a spin echo sequence.

[0022] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the reference period is any corrected period, and the using of the reference period to correct the magnetic resonance image of the current period includes:

[0023] Obtain distortion correction information according to the first position of the target tissue in the magnetic resonance image of the reference period and the second position of the target tissue in the magnetic resonance image of the reference period; wherein, the reference period is the scanned image of the positioning sequence obtained by pre-scanning a reference area, and the reference area covers the target area;

[0024] Correct the magnetic resonance image of the current period according to the distortion correction information.

[0025] A magnetic resonance three-dimensional temperature monitoring device provided by the present invention, before obtaining continuous magnetic resonance images covering the target area through fast magnetic resonance imaging, includes:

[0026] Obtain a positioning sequence scan image, establish a positioning three-dimensional structure diagram according to the positioning sequence scan image, and register the positioning three-dimensional structure diagram with the preoperative three-dimensional image to determine the spatial position of the target area; wherein, the target area is outlined or automatically segmented in the preoperative three-dimensional image;

[0027] Determine the scan parameters of the fast magnetic resonance imaging according to the position of the target area, or determine the scan parameters of the fast magnetic resonance imaging according to a user input instruction

[0028] A magnetic resonance three-dimensional temperature monitoring device provided by the present invention, determining the scan parameters of the fast magnetic resonance imaging according to the position of the target area includes:

[0029] Taking the direction of the thinnest sandwich as the initial scan direction according to the shape of the target area; wherein, the thinnest sandwich refers to two parallel planes that sandwich the target area so that the distance between the planes is the smallest.

[0030] A magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the determining the scan parameters of the fast magnetic resonance imaging according to the position of the target area includes:

[0031] Taking the cross-section perpendicular to the fiber direction as the scan direction;

[0032] Determine the number of scan layers according to the target area in the positioning three-dimensional structure diagram, or determine the number of scan layers according to a user input instruction.

[0033] A magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the host running the executable instruction also realizes:

[0034] Generate a three-dimensional amplitude map according to the amplitude maps of the continuous magnetic resonance images, and judge whether the current magnetic resonance scan range covers the target area according to the three-dimensional amplitude map. If not, re-determine the scan parameters.

[0035] A magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the judging whether the current magnetic resonance scan range covers the target area includes:

[0036] Compare the background regions in the three-dimensional amplitude maps of the current period and the previous period. If the change in the cumulative gray value in the background region does not exceed a preset threshold, it is confirmed that the current magnetic resonance scanning range covers the target area; if it exceeds the preset threshold, further judgment is made. If the target area intersects the boundary of the three-dimensional amplitude map of the current period, or the three-dimensional amplitude map of the current period does not contain the target area, it is determined that the current magnetic resonance scanning range does not cover the target area.

[0037] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the re-determining the scanning parameters includes: registering the background regions of the three-dimensional amplitude maps of the current period and the previous period, and determining new scanning parameters according to the registration relationship of the background regions.

[0038] According to a magnetic resonance three-dimensional temperature monitoring device provided by the present invention, the host running the executable instructions further realizes:

[0039] In the next fiber ablation process, fuse the ablated regions in the previous fiber ablation process into the three-dimensional amplitude map of the current period as the initial ablated region of this fiber ablation process.

[0040] The present invention also provides a magnetic resonance-guided laser ablation system, which is characterized by including: a magnetic resonance device, a laser ablation kit, and the magnetic resonance three-dimensional temperature monitoring device according to any one of the foregoing.

[0041] The present invention also provides a magnetic resonance three-dimensional temperature monitoring method, including:

[0042] Obtain continuous magnetic resonance images covering the target area through fast magnetic resonance imaging;

[0043] Generate a three-dimensional temperature map according to the continuous magnetic resonance images;

[0044] Fusion-display the three-dimensional temperature map with the three-dimensional image before surgery.

[0045] The present invention also provides a method for correcting magnetic resonance device scanning parameters, including:

[0046] Periodically perform fast magnetic resonance imaging on the target area, and obtain a set of continuous magnetic resonance images in each period;

[0047] For each set of magnetic resonance images, establish a three-dimensional temperature map according to the phase map in the magnetic resonance images, and establish a three-dimensional amplitude map according to the amplitude map in the magnetic resonance images; wherein, the three-dimensional temperature map is used for fusion-display with the three-dimensional image before surgery;

[0048] Compare the background regions in the three-dimensional amplitude maps of the current period and the previous period. If the change in the cumulative gray value in the background region is greater than a preset threshold, it is determined that the patient has moved, and the initial scanning parameters are corrected according to the registration relationship between the three-dimensional amplitude maps of the current period and the previous period to obtain new scanning parameters.

[0049] The present invention also provides an ablation evaluation method for a magnetic resonance-guided laser interstitial thermotherapy system, which is characterized by including:

[0050] Periodically perform rapid magnetic resonance imaging on the target area, and obtain a set of consecutive magnetic resonance images in each period;

[0051] For each set of magnetic resonance images, establish a three-dimensional temperature map according to the phase map in the magnetic resonance images;

[0052] Judge the ablation state of the tissue according to the three-dimensional temperature maps of each period and the corresponding acquisition times. The method for calculating ablation according to the temperature map can be a conventional method, such as using various known methods in the art such as the Arrhenius formula.

[0053] The magnetic resonance three-dimensional temperature monitoring device, system, and method provided by the present invention have at least one or more of the following beneficial effects:

[0054] 1. The position of the target tissue and the scanning parameters are accurately determined, which is convenient for accurately acquiring magnetic resonance images for the target area during intraoperative ablation. By obtaining rapid magnetic resonance sequence scanning images for establishing a three-dimensional temperature map, three-dimensional temperature data is obtained while meeting the real-time requirement, which is convenient for the user to determine the temperature state at each position in the target area, making the temperature monitoring more comprehensive and the evaluation of the ablation state more accurate.

[0055] 2. By reconstructing a three-dimensional structure diagram for positioning through positioning sequence scanning and registering it with the preoperative three-dimensional image, the position of the target tissue and the target area can be accurately determined, and on this basis, the scanning parameters can be flexibly (automatically or user input) and reasonably set.

[0056] 3. Since a three-dimensional temperature map is reconstructed and combined with the corresponding patient movement judgment step, when the patient moves but the target area does not exceed the magnetic resonance scanning range, there is no need to perform positioning sequence scanning again, ensuring the smooth progress of the ablation process; when the patient moves and the target area exceeds the magnetic resonance scanning range, based on the three-dimensional registration relationship, new scanning parameters can be conveniently determined, and there is also no need to perform positioning sequence scanning again, improving the surgical efficiency.

[0057] 4. By fusing and displaying the three-dimensional temperature map with the preoperative three-dimensional image, and according to the user's cross-section display instruction / cross-section adjustment instruction, the corresponding cross-section effect is displayed, which is convenient for the user to observe the temperature state at any position and angle.

[0058] 5. The three-dimensional temperature map realizes the monitoring of the simultaneous ablation of two or more optical fibers, which speeds up the surgical efficiency, shortens the surgical time, calculates the ablated area more accurately through the three-dimensional temperature map, and facilitates the user to intuitively observe the position and size of the current ablated area by displaying the current ablated area into the preoperative three-dimensional image.

[0059] 6. The magnetic resonance images are quickly obtained through inter-layer downsampling / intra-layer downsampling, and continuous magnetic resonance images are obtained through the "repair" method, shortening the imaging cycle and meeting the real-time requirement of monitoring temperature during the laser ablation process.

[0060] 7. The target area is scanned by the magnetic resonance fast imaging sequence, and the obtained magnetic resonance images are corrected by using the reference period to obtain continuous magnetic resonance images, shortening the imaging cycle and meeting the real-time requirement of monitoring temperature during the laser ablation process.

[0061] 8. The method of the present invention can not only be used for temperature monitoring of laser ablation, but also for temperature and ablation monitoring caused by other energy methods such as confocal ultrasound. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0063] Figure 1 is a schematic structural diagram of a magnetic resonance three-dimensional temperature monitoring device provided by the present invention;

[0064] Figure 2 is a schematic structural diagram of a magnetic resonance-guided laser ablation system provided by the present invention;

[0065] Figure 3 is a schematic flow diagram of a magnetic resonance three-dimensional temperature monitoring method provided by the present invention;

[0066] Figure 4 is a schematic flow diagram of a magnetic resonance equipment scan parameter correction method provided by the present invention;

[0067] Figure 5 is a schematic flow diagram of an ablation evaluation method of a magnetic resonance-guided laser interstitial thermotherapy system provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0069] The following will describe Figures 1-5 a magnetic resonance three-dimensional temperature monitoring device, system and method of the present invention.

[0070] Figure 1 is a schematic structural diagram of a magnetic resonance three-dimensional temperature monitoring device provided by the present invention. As Figure 1 shown, the device 100 includes a host 110 and a display device 120; the host 110 can adopt a general computer architecture, in which executable instructions are stored. When the executable instructions are executed by the host, the following functions are realized:

[0071] S11. Obtain continuous magnetic resonance images covering the target area through fast magnetic resonance imaging

[0072] Specifically, the magnetic resonance device performs fast magnetic resonance scanning on the target area according to the scanning parameters, periodically collects fast magnetic resonance images, and the host 110 processes the magnetic resonance images collected by the magnetic resonance device to obtain a set of continuous magnetic resonance images covering the target area. Here, "continuous" means that the magnetic resonance scanning images of each layer are continuously adjacent, and there is no "missing area" between layers. Each group of magnetic resonance images can be used to establish a three-dimensional temperature map and a three-dimensional structure map of the current scanning period, facilitating real-time update of the monitoring data. Here, the fast magnetic resonance imaging is an imaging method capable of efficiently collecting continuous magnetic resonance images. For example, a magnetic resonance scanning method that takes measures such as shortening the repetition time TR, collecting fewer phase encoding lines, using parallel acquisition technology, using an echo planar imaging sequence, using a gradient echo imaging sequence, using EPI, PRESTO, b-SSFP imaging sequence, etc.

[0073] Fast magnetic resonance imaging can acquire magnetic resonance image data with higher resolution and more layers, facilitating the establishment of a three-dimensional temperature map. While meeting the real-time requirements of intraoperative magnetic resonance temperature monitoring, it can also contain more temperature data. For example, in the prior art, magnetic resonance images of 3 parallel tomographies are acquired per cycle, and the data resolution of each layer (i.e., the slice thickness of each layer) is 3 mm, and the acquisition time of the data per cycle is approximately 4 s. In an embodiment of the present invention, a fast magnetic resonance sequence is used for scanning, 20 consecutive magnetic resonance images are acquired per cycle, the data resolution of each layer is 1 mm, and the acquisition time of the data per cycle is 5 - 6 s. The data resolution is higher, and the real-time requirements can still be met. In the present invention, fast magnetic resonance imaging refers to magnetic resonance scanning with a data acquisition cycle less than 6 s.

[0074] After the magnetic resonance device acquires fast magnetic resonance images, the host computer can receive and obtain the above data from the magnetic resonance device for data processing.

[0075] S12. Generate a three-dimensional temperature map according to the continuous magnetic resonance images;

[0076] Specifically, according to the principle of magnetic resonance temperature measurement, the phase change in two different magnetic resonance images corresponds to the temperature change. That is to say, a temperature map can be generated according to the magnetic resonance images. Since the acquired magnetic resonance images include a continuous plurality of "tomographies", a three-dimensional temperature map can be generated accordingly, and the temperature change situation can be observed in three-dimensional space, better guiding the ablation process and evaluating the ablation state.

[0077] S13. Fuse and display the three-dimensional temperature map with the preoperative three-dimensional image.

[0078] Specifically, fuse the three-dimensional temperature map with the preoperative three-dimensional image and display it on the display device 120, and display the temperature information at each position in the preoperative three-dimensional image (structural image). Further, corresponding colors can be rendered in the preoperative three-dimensional image according to the temperature data in the temperature map to visually represent the temperature state at each position.

[0079] In this embodiment, continuous magnetic resonance images covering the target area are efficiently acquired through fast magnetic resonance imaging for establishing a three-dimensional temperature map. While meeting the real-time temperature monitoring during the laser ablation surgery process, three-dimensional temperature data is obtained, facilitating the user to determine the temperature state at each position in the target area, making the temperature monitoring more comprehensive and the evaluation of the ablation state more accurate.

[0080] Based on any embodiment, in an embodiment, S11 includes:

[0081] Determine the target area to be sampled in the current cycle according to the preset magnetic resonance downsampling rule;

[0082] Perform magnetic resonance scanning on the target area to obtain a magnetic resonance image of the target area;

[0083] According to the magnetic resonance image of the target area, obtain the continuous magnetic resonance images covering the target area in the current cycle through a reconstruction algorithm.

[0084] Specifically, during the intraoperative ablation process, the magnetic resonance device needs to image the target area to be ablated and its nearby tissues to monitor the temperature state, that is, the "continuous magnetic resonance images obtained in each cycle" need to cover the target area. To achieve fast magnetic resonance imaging, when collecting magnetic resonance images in a specific cycle, only a part of the area "covering the target area" is imaged, and then the "continuous magnetic resonance images" covering the target area are repaired by the method of "supplementary data". The magnetic resonance downsampling rule is a rule preset for determining the target area to be scanned in the current cycle. For example, to completely cover the target area, n layers of magnetic resonance images need to be collected. The preset magnetic resonance downsampling rule is the scanning strategy (i.e., interlayer downsampling) for which layers to scan and which layers not to scan in the current cycle. More specifically, for example, odd layers are collected in one cycle, and even layers are collected in the next cycle, and so on; another example is that 3i + 1 layers (i = 0, 1, 2, 3...) are collected in one cycle, 3i + 2 layers (i = 0, 1, 2, 3...) are collected in the next cycle, and 3i + 3 layers (i = 0, 1, 2, 3...) are collected in the next cycle, and so on; another example is that the preset magnetic resonance downsampling rule can also be judged in combination with the number of layers to be sampled. When the number of layers exceeds the layer threshold, the first strategy is adopted, and when the number of layers does not exceed the layer threshold, the second strategy is adopted.

[0085] Among them, the layer threshold can be a preset value used to judge whether the number of layers to be scanned in the target area is too large, so as to adopt different interlayer downsampling strategies, such as the layer threshold being 10, 15, 18, etc. The first strategy is a downsampling strategy set for the case where the number of layers to be sampled is too large, and the second strategy is a downsampling strategy set for the case where the number of layers to be sampled is small. Therefore, the layer interval of the first strategy is greater than that of the second strategy. For example, when the number of layers exceeds 12, it is divided into an odd-layer collection cycle and an even-layer collection cycle. When the number of layers does not exceed 12, sampling is performed on each layer within one cycle.

[0086] It should be noted that since the target area to be scanned remains unchanged, there will be the same spatial redundant information between frames. An accelerated acquisition method of interlayer downsampling can be adopted to accelerate the acquisition of magnetic resonance images. For example, EPI or GRE sequences can be used. By using the accelerated acquisition method of interlayer downsampling, the image acquisition speed can be increased. In this way, only some layers of the target area are scanned in each period to accelerate the acquisition of magnetic resonance images. Then, the magnetic resonance image data acquired in the current period (or combined with the previous period) can be used to reconstruct a complete image, so as to ensure the quality of the acquired image and achieve high spatio-temporal resolution and large-range temperature imaging without changing the image quality and scanning time.

[0087] In an optional implementation manner of this embodiment, the preset magnetic resonance downsampling rule is to sample odd layers and even layers by cycle; according to the preset magnetic resonance downsampling rule, determining the target area to be sampled in the current period includes:

[0088] Determining the sampled layers scanned in the previous period;

[0089] When the sampled layer in the previous period is an odd layer, determining that the target layer to be sampled in the current period is an even layer;

[0090] When the sampled layer in the previous period is an even layer, determining that the target layer to be sampled in the current period is an odd layer.

[0091] That is to say, the layers sampled in two adjacent periods are different. In practical applications, the sampled layers scanned in the previous period can be determined first. If the sampled layer scanned in the previous period is an odd layer, then the even layers are sampled in the current period. If the sampled layer scanned in the previous period is an even layer, then the odd layers are sampled in the current period. For example, the continuous magnetic resonance images covering the target area include 1 - 10 layers. One period scans layers 1 / 3 / 5 / 7 / 9, and the next period samples layers 2 / 4 / 6 / 8 / 10.

[0092] In this embodiment, the area to be sampled is sampled by odd layers and even layers. One period samples odd layers, and the other period samples even layers. Only some layers of the target area are scanned in each period, and the layers sampled in two adjacent areas do not repeat, with maximum downsampling, so as to improve the acquisition speed of the magnetic resonance image sequence to meet the clinical requirements of magnetic resonance-based temperature measurement and ablation calculation.

[0093] In an optional implementation manner of this embodiment, the preset magnetic resonance downsampling rule is to adopt the first strategy when the number of layers to be sampled exceeds the layer threshold, and adopt the second strategy when it does not exceed the layer threshold; according to the set interlayer downsampling rule, determining the target layer to be sampled in the current period includes:

[0094] Obtaining the number of layers to be sampled of the continuous magnetic resonance images;

[0095] When the number of layers to be sampled exceeds the layer threshold, determine the target layer to be sampled in the current period according to the first strategy;

[0096] When the number of layers to be sampled does not exceed the layer threshold, determine the target layer to be sampled in the current period according to the second strategy.

[0097] Specifically, the layer threshold can be a preset value, which is used to judge whether the number of layers to be scanned in the target area is too large, so as to adopt different inter-layer downsampling strategies. For example, the layer threshold can be 10, 15, 18, etc. The first strategy is a downsampling strategy set for the case of too many layers to be sampled, and the second strategy is a downsampling strategy set for the case of fewer layers to be sampled. Therefore, the layer interval of the first strategy is greater than that of the second strategy. That is to say, due to too many layers to be sampled in the target area, the first strategy ignores more layers in one period without sampling to ensure the scanning speed. For example, the first strategy can sample every k - 1 layers in different periods, that is, sample the first layer in the first period, sample the (1 + k)th layer in the next period, and sample the (1 + 2k)th layer in the next period, and so on; the second strategy can sample every m - 1 layers in different periods, where m is less than k.

[0098] In specific implementation, the first strategy or the second strategy can be configured based on actual requirements. The first strategy or the second strategy can also sample odd layers and even layers respectively in the above-mentioned interval periods.

[0099] Exemplarily, assume that the target area includes 1 - 12 layers to be sampled, and the layer threshold is 10. At this time, the number of layers to be sampled in the target area exceeds the layer threshold. In one period, sample the 1st / 4th / 7th / 10th layers, sample the 2nd / 5th / 8th / 11th layers in the second period, and sample the 3rd / 6th / 9th / 12th layers in the third period. Additionally, assume that the layer threshold is 15. At this time, the number of layers to be sampled in the target area does not exceed the layer threshold. At this time, sample the 1st / 3rd / 5th / 7th / 9th / 11th layers in one period, and sample the 2nd / 4th / 6th / 8th / 10th / 12th layers in the next period. That is to say, when the number of layers to be sampled in the target area exceeds the layer threshold, sample every 2 layers in each period; when the number of layers to be sampled in the target area does not exceed the layer threshold, sample every 1 layer in each period.

[0100] It should be noted that when the number of layers to be sampled exceeds the layer threshold, it indicates that there are more layers to be sampled in the target area. At this time, the first strategy can be used to determine the target layer to be sampled in the current period. When the number of layers to be sampled does not exceed the layer threshold, it indicates that there are fewer layers to be sampled in the target area, and the second strategy is used to determine the target layer to be sampled in the current period. For different situations of the target area, different inter-layer downsampling strategies can be adopted respectively, which can adapt to more application scenarios and improve applicability and flexibility.

[0101] In an alternative embodiment of this example, in addition to using the inter-layer downsampling method to increase the scanning speed, the intra-layer downsampling method can also be used to further increase the scanning speed to meet the requirements of temperature monitoring; fast magnetic resonance imaging scans by columns, and according to the preset magnetic resonance downsampling rule, determines the target area to be sampled in the current period, including:

[0102] Determine the data columns to be sampled in the current period according to the preset intra-layer downsampling rule;

[0103] Perform magnetic resonance scanning on the data columns to be sampled to obtain a magnetic resonance image sequence of the target area.

[0104] It should be noted that the magnetic resonance fast imaging sequence scans by columns, such as GRE. That is, when scanning a certain layer, the magnetic resonance fast imaging sequence does not scan the entire layer at once, but scans a column of data in a layer at a time. For the magnetic resonance fast imaging sequence that scans by columns, in addition to the above-mentioned inter-layer downsampling, intra-layer downsampling can also be used, and only some columns in a layer are collected in one scan to increase the scanning speed. Additionally, it should be noted that if the magnetic resonance fast imaging sequence scans by layer, such as EPI, when scanning a certain layer, it scans the entire layer at once, and intra-layer downsampling cannot be performed, only inter-layer downsampling can be performed.

[0105] Specifically, the set intra-layer downsampling rule is a pre-set data column selection strategy for intra-layer data columns, that is, for a certain layer, which data columns to collect and which data columns not to collect. For example, the set intra-layer downsampling rule can be to collect the 2nth column data in the current period, the (2n + 1)th column data in the next period, the (2n + 2)th column data in the next period, and so on; or, use the method of 3n, 3n + 1, 3n + 2 to increase the data collection speed within the layer by 2 times or 3 times.

[0106] In practical applications, the set inter-layer downsampling rule is to select some column data from the column data of each layer for collection. According to the set intra-layer downsampling rule, it is possible to determine which data columns to be collected in the current period, and then scan the data columns to be collected in the target layer through the magnetic resonance fast imaging sequence to obtain the magnetic resonance image of the current period. In this way, for the target layer, only some data columns need to be collected, greatly improving the data collection speed within the layer.

[0107] It should be noted that for the target area (i.e., the ablation area), due to the continuity of temperature in physical space and time, the temperature information of adjacent positions can be used to estimate the temperature of the unsampled part, thus ensuring the temperature imaging quality of the target area.

[0108] In specific implementation, all samplings can be pre - carried out on the test area based on the temperature - measuring optical fiber to obtain a complete image through testing, and a down - sampled image is obtained by down - sampling the test area. Then, the complete image obtained through testing is used as a label, and the down - sampled image is used as the input of the deep - learning model to train the deep - learning model, so as to obtain a deep - learning model capable of reconstructing a complete image. Subsequently, the data sequence collected by down - sampling is input into the trained deep - learning model, and a reconstructed complete image sequence can be obtained.

[0109] In the embodiments of this specification, an accelerated acquisition method of inter - layer down - sampling and intra - layer down - sampling can be adopted. Only partial layers of the target area and partial data columns in these partial layers are scanned in each period to accelerate the acquisition of magnetic resonance images. Then, a complete image is reconstructed based on the collected data. When reconstructing the image, a deep - learning reconstruction algorithm is used to utilize the invariance of the spatial information of the target area and the continuity of temperature in the physical space and time to reconstruct the complete image information, thereby ensuring the quality of the acquired image. Without changing the image quality and scanning time, high spatio - temporal resolution and large - range temperature imaging are achieved.

[0110] It should be noted that in actual application scenarios, the methods of inter - layer down - sampling and intra - layer down - sampling can be used simultaneously to accelerate the acquisition of magnetic resonance images, or the method of inter - layer down - sampling or intra - layer down - sampling can be used alone to accelerate the acquisition of magnetic resonance images. The embodiments of this specification do not limit this. For example, the layers to be sampled in the target area can be determined, and each layer to be sampled is used as the layer to be scanned in the current period. Then, for each layer, based on the intra - layer down - sampling rule, it is determined which data columns are to be collected.

[0111] Based on any one of the embodiments, in one embodiment, according to the magnetic resonance image of the target area, a continuous magnetic resonance image of the current period is obtained through a reconstruction algorithm, including:

[0112] According to the magnetic resonance image of the target area, a continuous magnetic resonance image of the current period is obtained by interpolation; or,

[0113] According to the magnetic resonance image of the target area, interpolation is performed in combination with the magnetic resonance image of its complementary period to obtain a continuous magnetic resonance image of the current period.

[0114] Specifically, for example, the preset magnetic resonance down - sampling rule is to sample odd - numbered layers and even - numbered layers separately. One period collects 1 / 3 / 5 / 7 / 9 layers, and the next period collects 2 / 4 / 6 / 8 / 10 layers, and so on in a cycle. At T nMagnetic resonance data of layers 1 / 3 / 5 / 7 / 9 were collected periodically, and the data of layers 2 / 4 / 6 / 8 / 10 were missing. The missing magnetic resonance images of the even layers can be directly filled in by interpolation based on the magnetic resonance images of the odd layers. For example, based on the magnetic resonance images of layer 1 and layer 3, the magnetic resonance image of layer 2 can be filled in, and based on the magnetic resonance images of layer 3 and layer 5, the magnetic resonance image of layer 4 can be filled in, until continuous magnetic resonance images of 10 layers are obtained. Or, the missing data can also be filled in according to the complementary period. For example, on the basis of the magnetic resonance data of layers 1 / 3 / 5 / 7 / 9 collected in the T n period, the even-layer magnetic resonance data collected in the T n-1 period are also combined to fill in the even-layer data missing in the T n period, or the even-layer magnetic resonance data collected in the complementary periods such as T n-3 and T n-5 are also combined to fill in the even-layer data missing in the T n period. Generally, the structure / temperature state of the patient's target tissue does not change drastically. Therefore, the data in the complementary period of the current period can be used to provide a reference for the "interpolation process" of the current period, further improving the repair accuracy. It can be understood that the above only exemplifies the "repair" process in the case of interlayer downsampling with an interval of one layer. In the case of a larger interval between layers, the missing layers can also be filled in by linear interpolation (or further combined with the complementary period), and the missing data can be repaired in the same way in the case of intralayer downsampling.

[0115] In this embodiment, continuous magnetic resonance images are obtained by interpolation based on the downsampled magnetic resonance images, which improves the efficiency of collecting magnetic resonance images, meets the requirement of real-time monitoring of temperature during the laser ablation process, and further combines the complementary period to fill in the missing magnetic resonance data, improving the accuracy of the obtained continuous magnetic resonance images.

[0116] Based on any embodiment, in one embodiment, S12 includes:

[0117] Periodically scan the target area by magnetic resonance fast imaging sequence;

[0118] Use the reference period to correct the magnetic resonance images of the current period to obtain corrected magnetic resonance images.

[0119] Specifically, the magnetic resonance fast imaging sequence can be echo planar imaging (EPI), and the obtained magnetic resonance image is the EPI sequence. Among them, EPI is one of the fastest magnetic resonance imaging methods so far. It is a special form of gradient echo. It uses a fast reverse gradient to generate a series of gradient echoes within a single relaxation time (TR) and phase-encode them respectively, filling them into the corresponding k-space to achieve cross-sectional imaging.

[0120] The fast magnetic resonance imaging sequence can also be obtained by scanning the target area based on other fast scanning algorithms, such as shortening the repetition time TR, acquiring fewer phase encoding lines, parallel acquisition technology, gradient echo magnetic resonance pulse sequence (GRE), gradient echo translation imaging (PRESTO), balanced steady-state free precession imaging (B-SSFP), etc.

[0121] The fast magnetic resonance imaging sequence can often complete the acquisition of an image in a few milliseconds. However, information may be lost during the fast acquisition process, resulting in distortion of the acquired image, and further leading to inaccurate temperature maps constructed subsequently, affecting the operation. Taking the echo planar imaging (EPI) as an example of the fast magnetic resonance imaging sequence, EPI can complete the acquisition of an image in a few milliseconds. Therefore, this technology is one of the fast signal acquisition methods, and fast scanning of 10-20 layers of images (1-4 s) can be achieved through the fast EPI sequence. However, since the EPI sequence generates signals through continuous alternating changes of gradients and there is no refocusing pulse to correct the inhomogeneity of the main magnetic field and the error of phase information, as the EPI factor increases, the accumulated phase error becomes larger and larger, and the relevant deformation and artifacts of the image will also become heavier.

[0122] In practical applications, since the position of the patient or the phantom remains unchanged during the scanning of the target area by the fast magnetic resonance imaging sequence, the tissue spatial information in the same scanning plane remains unchanged, such as blood vessels, tumor boundaries, cerebral sulci and gyri, etc., that is, the spatial distribution of the target area is basically unchanged. Therefore, the present invention uses the unchanged spatial position information to correct the distortion generated during the fast scanning process, so as to achieve the acquisition of a fast 3D temperature sequence without reducing the spatial resolution. Specifically, the reference period without spatial distortion (or already completed distortion correction) can be used to correct the obtained magnetic resonance image sequence of the current period, and the corrected magnetic resonance image of the current period can be obtained, so as to achieve efficient and accurate three-dimensional temperature detection.

[0123] Based on the previous embodiment, in one embodiment, the reference period is the positioning sequence scan image obtained by pre-scanning the reference area, and the reference area covers the target area.

[0124] Specifically, the localization sequence scan can be T1WI (T1-weighted imaging), T2WI (T2-weighted imaging), DWI (diffusion-weighted imaging), SE (spin echo sequence imaging) scan, etc. The range of the localization sequence scan is relatively large. For example, when laser ablation is to be performed on an intracranial tumor, the head (reference area) of the patient is scanned by the localization sequence. Based on the localization sequence scan, the location of the tumor (target area) can be determined, which facilitates a small-range and rapid magnetic resonance imaging of the tumor (target area) by the magnetic resonance device during the laser ablation process, improving the real-time performance of temperature detection. It can be understood that the imaging range of the above-mentioned localization sequence scan images is relatively large and the imaging accuracy is high. In this embodiment, it is also used as a reference period to correct the magnetic resonance rapid sequence images collected during the operation and repair the distortion therein. Specifically, using the reference period to correct the magnetic resonance image of the current period to obtain a corrected magnetic resonance image includes:

[0125] Obtain the localization sequence scan images obtained by pre-scanning;

[0126] Correct the magnetic resonance image of the current period according to the localization sequence scan images to obtain a corrected magnetic resonance image.

[0127] In a possible implementation, the third position information of the target tissue (such as blood vessels, tumor boundaries, cerebral sulci, etc.) in the magnetic resonance image of the current period can be determined first, and the fourth position information of the target tissue in the localization sequence scan images can be determined. Then, a spatial transformation matrix is calculated based on the third position information and the fourth position information, and the spatial transformation matrix is used as the distortion correction information to correct the magnetic resonance image sequence of the current period to obtain the corrected magnetic resonance image of the current period. In another implementation, the localization sequence scan images and the magnetic resonance image sequence of the current period can be directly compared to correct the magnetic resonance image of the current period to obtain the corrected magnetic resonance image of the current period, and at the same time, the distortion correction information is output and stored for subsequent use.

[0128] In this embodiment, directly correcting the magnetic resonance images obtained in one period with the localization sequence scan images can eliminate the distortion generated during the intraoperative magnetic resonance rapid imaging sequence scan, ensure the accuracy of the magnetic resonance images, and thus ensure the accuracy of the subsequent constructed three-dimensional temperature map.

[0129] Based on any one of the embodiments, in one embodiment, the reference period is any corrected period. Using the reference period to correct the magnetic resonance image of the current period includes:

[0130] Obtain distortion correction information based on the first position of the target tissue in the magnetic resonance image of the reference period and the second position of the target tissue in the magnetic resonance image of the reference period; wherein, the reference period is the positioning sequence scan image obtained by pre-scanning the reference region, and the reference region covers the target area.

[0131] Correct the magnetic resonance image of the current period according to the distortion correction information.

[0132] Specifically, in this embodiment, the reference period is the period of performing a positioning sequence scan on the reference region, and the reference period is the corrected period. During the process of correcting the magnetic resonance image of the current period, first obtain the first position of the target tissue (such as blood vessels, tumor boundaries, cerebral sulci, etc.) in the reference period and the second position of the target tissue in the reference period, calculate the spatial transformation matrix according to the first position and the second position, and use this spatial transformation matrix as the distortion correction information to correct the magnetic resonance image sequence of the current period and obtain the corrected magnetic resonance image of the current period.

[0133] In this embodiment, the distortion correction is not directly performed based on the positioning sequence scan image, which reduces the difficulty of calculating the distortion correction information and improves the data processing efficiency. In addition, the correction process does not have to wait until the magnetic resonance data of the current period is completely acquired before execution. The magnetic resonance image of the current period is directly corrected according to the distortion correction information of the reference period, which can further improve the real-time performance of temperature detection.

[0134] Based on any one of the embodiments, in one embodiment, correcting the magnetic resonance image of the current period according to the reference period to obtain the corrected magnetic resonance image of the current period includes:

[0135] Obtain the distortion correction information of the previous period according to the reference period and the previous period of the current period;

[0136] Use the distortion correction information to correct the magnetic resonance image of the current period to obtain the corrected magnetic resonance image of the current period;

[0137] Based on the magnetic resonance image of the current period and the positioning sequence scan image, determine and store the distortion correction information of the current period, wherein the distortion correction information of the current period is used to correct the magnetic resonance image of the next period of the current period.

[0138] It should be noted that the distortion correction information of the previous period can be obtained first according to the reference period and the previous period of the current period, and then the magnetic resonance image of the current period can be directly corrected using the distortion correction information of the previous period to obtain the corrected magnetic resonance image of the current period. After that, the distortion correction information of the current period can be determined for use in the next period of correction. That is, each period is corrected based on the distortion correction information of the previous period.

[0139] As an example, after the reference period, at the second period, since the previous period of the second period is the reference period, at this time, based on the positioning sequence image of the reference period and the magnetic resonance image of the second period, the magnetic resonance image of the second period can be corrected to obtain the corrected magnetic resonance image sequence of the second period, and at the same time, the distortion correction information of the second period is obtained and stored; afterwards, at the third period, the distortion correction information of the second period can be directly obtained to correct the magnetic resonance image of the third period to obtain the corrected magnetic resonance image sequence of the third period, and then based on the positioning sequence scanning image of the reference period and the magnetic resonance image of the third period, the distortion correction information of the third period can be calculated and stored; afterwards, at the fourth period, the distortion correction information of the third period can be directly obtained to correct the magnetic resonance image of the fourth period, and so on.

[0140] In this embodiment, each period is corrected based on the distortion correction information of the previous period, which can reduce the accumulation of distortion information in multiple periods and improve the accuracy of correction.

[0141] In an alternative implementation manner of this embodiment, according to the magnetic resonance image and the positioning sequence scanning image of the current period, the distortion correction information of the current period is determined and stored, including:

[0142] Determine the fifth position information of the target tissue in the magnetic resonance image of the current period;

[0143] Determine the sixth tissue position information of the target tissue in the positioning sequence scanning image;

[0144] According to the fifth position information and the sixth position information, calculate the spatial transformation matrix, and use the spatial transformation matrix as the distortion correction information and store it.

[0145] Specifically, the target tissue is a tissue with an unchanged position in the patient or the phantom during the scanning process, such as blood vessels, tumor boundaries, cerebral sulci and gyri, etc.

[0146] It should be noted that the fifth position information of the target tissue in the magnetic resonance image of the current period can be determined through image analysis, and the second tissue position information of the target tissue in the positioning sequence scanning image can be determined, and then the spatial transformation matrix is calculated according to the first tissue position information and the second tissue position information. This spatial transformation matrix is the distortion correction information between the first tissue position information and the second tissue position information. In this way, the position information of the invariant target tissue is used to determine the distortion correction information of the current period and store it. At the next period, the distortion correction information of the current period can be directly obtained for correction.

[0147] In an alternative implementation of this embodiment, in addition to the method where the magnetic resonance images obtained in each cycle are directly corrected based on the positioning sequence scan images scanned in the reference cycle, or each cycle is directly corrected based on the distortion correction information of the previous cycle, any cycle can be optionally selected as a constant reference cycle to correct the magnetic resonance images of each cycle. Specifically, correcting the magnetic resonance image of the current cycle according to the reference cycle to obtain the corrected magnetic resonance image of the current cycle includes:

[0148] Select any cycle as the constant reference cycle;

[0149] Obtain the constant distortion correction information according to the reference and constant reference cycles;

[0150] Use the constant distortion correction information to correct the magnetic resonance image of the current cycle to obtain the corrected magnetic resonance image of the current cycle.

[0151] It should be noted that any cycle can be selected as the constant reference cycle, and then the constant distortion correction information is obtained according to the reference cycle and the constant reference cycle. After that, the obtained constant distortion correction information is used to correct the magnetic resonance image of the current cycle to obtain the corrected magnetic resonance image of the current cycle. That is to say, the magnetic resonance images of each cycle are corrected based on the constant distortion correction information, and the constant distortion correction information can be determined based on any selected cycle, and the correction method is more flexible and can adapt to different scenario requirements.

[0152] Among them, the specific implementation process of obtaining the constant distortion correction information according to the reference cycle and the correction reference cycle can refer to the specific implementation process of determining the distortion correction information of the current cycle based on the magnetic resonance image of the current cycle and the positioning sequence scan image, which will not be elaborated here.

[0153] Based on any of the above embodiments, in an embodiment, before S11 includes:

[0154] Obtain the positioning sequence scan image, establish a positioning three-dimensional structure diagram according to the positioning sequence scan image, and register the positioning three-dimensional structure diagram with the preoperative three-dimensional image to determine the position of the target area; wherein, the target area is outlined or automatically segmented in the preoperative three-dimensional image;

[0155] Determine the scanning parameters of the fast magnetic resonance imaging according to the position of the target area, or determine the scanning parameters of the fast magnetic resonance imaging according to the user input instruction.

[0156] Specifically, in order to perform laser interstitial thermotherapy, it is necessary to determine the position of the target site (i.e., the human body part where the ablation operation is to be performed, such as the liver, spleen, prostate, head, etc.) in the operating room space, and determine the position of the target area to be ablated contained therein in the operating room space, so as to accurately monitor the temperature of the target area (and its surrounding tissues) through magnetic resonance equipment. The positions of the target site and the target area are determined by positioning sequence scanning, and the positioning sequence scanning can be T1WI (T1-weighted imaging), T2WI (T2-weighted imaging), DWI (diffusion-weighted imaging) scanning, etc. Here, the positioning sequence scanning has a large enough scanning range to cover the target site and the target area. Preferably, the imaging method of the positioning sequence scanning image is consistent with that of the preoperative three-dimensional image to improve the registration accuracy with the preoperative three-dimensional image. The positioning sequence scanning image contains a series of amplitude maps, and based on this series of amplitude maps, a three-dimensional amplitude map (i.e., a positioning three-dimensional structure diagram) for positioning the target site can be reconstructed, and the target site and the target area therein can be observed in the positioning three-dimensional structure diagram.

[0157] Since the medical images of the target site have been collected preoperatively, and the preoperative three-dimensional image has been established, and the target area has been outlined from the preoperative three-dimensional image, or the target area has been automatically semantically segmented from the preoperative three-dimensional image through a semantic segmentation model, on this basis, by registering the positioning sequence scanning image with the preoperative three-dimensional image, the position of the target area in the positioning sequence scanning image can be correspondingly determined; of course, the target area position can also be directly outlined or automatically semantically segmented based on the positioning sequence scanning image.

[0158] According to the position of the target area, scanning parameters can be determined, such as the scanning direction, the number of scanning layers, the scanning position, the scanning resolution, etc. Among them, the scanning direction is the direction of the tomogram, the number of scanning layers is the number of magnetic resonance images collected in each scanning cycle to cover the target area (such as 10 layers, 15 layers, 18 layers, etc.), the scanning position is the collection position of the multi-layer magnetic resonance images, and the scanning resolution is the slice thickness of each layer of magnetic resonance images (such as 1 mm, 2 mm, 3 mm, etc.). The scanning parameters can be automatically set by an application program. For example, the number of scanning layers is automatically set according to the size of the target area and the scanning resolution; some parameters can also be set randomly (for example, the scanning direction is set randomly); the scanning parameters can also be determined according to the user's input instructions. For example, the user selects the scanning direction that is convenient for observing a certain specific structure according to the tissue structure to be observed. Further, a certain margin of the number of scanning layers can also be set so that the scanning range of magnetic resonance includes the target area, which is convenient for monitoring the current ablation boundary and determining whether the normal tissues around the target area are ablated by mistake.

[0159] In this embodiment, the three-dimensional structure diagram for positioning is reconstructed by scanning the positioning sequence and registered with the preoperative three-dimensional image, accurately determining the position of the target area. On this basis, the scanning parameters are reasonably set, laying a foundation for collecting intraoperative magnetic resonance images and improving the quality of the three-dimensional temperature map.

[0160] Based on the above embodiment, in one embodiment, determining the scanning parameters of the fast magnetic resonance imaging according to the position of the target area includes:

[0161] According to the shape of the target area, taking the direction of the thinnest sandwich as the initial scanning direction; wherein, the thinnest sandwich refers to two parallel planes that sandwich the target area so that the plane spacing is the smallest.

[0162] Specifically, the position of the target area represents the actual space occupied by the target area, that is, it contains the (surface) shape information of the target area. When the target area is sandwiched by two parallel planes and the distance between the two parallel planes is the smallest, it constitutes the "thinnest sandwich". Taking the direction of the thinnest sandwich as the scanning direction makes the overall scanning layer thickness of the intraoperative magnetic resonance scanning the smallest and the number of scanning layers the least. Correspondingly, the magnetic resonance scanning cycle can be shortened and the update frequency of the three-dimensional temperature map can be increased.

[0163] In this embodiment, combined with the scenario of laser interstitial thermotherapy, according to the shape of the target area, taking the direction of the thinnest sandwich as the scanning direction, the magnetic resonance scanning parameters are optimized, the acquisition rate of the magnetic resonance image and the update frequency of the three-dimensional temperature map are improved, and while improving the temperature monitoring effect, the real-time requirements of the clinic are also met.

[0164] Based on any of the above embodiments, in one embodiment, before S11 includes:

[0165] Obtain the positioning sequence scan image, establish a positioning three-dimensional structure diagram according to the positioning sequence scan image, and display the positioning three-dimensional structure diagram through the display device;

[0166] Determine the position and scanning parameters of the target site according to the user input instruction.

[0167] Specifically, the position of the target site is determined by the positioning sequence scan. The positioning sequence scan can be T1WI (T1-weighted imaging), T2WI (T2-weighted imaging), DWI (diffusion-weighted imaging) scan, etc. The positioning sequence scan image contains a series of amplitude maps. According to this series of amplitude maps, a three-dimensional structure diagram for positioning the target site (i.e., the positioning three-dimensional structure diagram) can be reconstructed. Display the positioning three-dimensional structure diagram in the display device 120 to facilitate the user to observe and determine the position of the target site and input the scanning parameters.

[0168] Based on any of the above embodiments, in one embodiment, determining the scanning parameters of the fast magnetic resonance imaging according to the position of the target area includes:

[0169] Taking the cross-section perpendicular to the fiber direction as the scanning direction;

[0170] Determining the number of scanning layers according to the target area in the positioning three-dimensional structure diagram, or determining the number of scanning layers according to a user input instruction.

[0171] Specifically, the positioning sequence scan images include a series of amplitude images. Based on this series of amplitude images, a three-dimensional structure diagram (i.e., the positioning three-dimensional structure diagram) for positioning the target site can be reconstructed. The target site (and the target area) can be observed in the positioning three-dimensional structure diagram. In addition, optical fibers are implanted in the target site to perform laser ablation on the target area, and it is convenient for the user to observe and determine the actual position of the optical fiber (position information such as the fiber direction and fiber depth) in the positioning three-dimensional structure diagram. The distal end of the optical fiber (i.e., the end implanted in the target site) includes a light-emitting section, and the light-emitting section can emit laser light to the target area circumferentially or directionally. To facilitate monitoring the heating effect of the emitted laser on the target area, intraoperative magnetic resonance scanning is performed with the cross-section perpendicular to the fiber direction as the scanning direction.

[0172] Further, during the laser ablation process, multiple optical fibers can be used to ablate the target area at the same time. At this time, one optical fiber can be randomly determined, or one optical fiber can be selected by the user, and intraoperative fast magnetic resonance scanning is performed with the cross-section perpendicular to the direction of this optical fiber as the scanning direction.

[0173] Further, since intraoperative fast magnetic resonance scanning needs to cover the target area, the scanning position can be determined according to the position of the target area, and the number of scanning layers can be determined according to the size of the target area in the positioning three-dimensional structure. The number of scanning layers is positively correlated with the size of the target area. Of course, the positioning three-dimensional structure can also be presented on a display device, and the user can determine scanning parameters such as the number of scanning layers.

[0174] In this embodiment, the actual position of the optical fiber is determined by the positioning sequence scan, and the cross-section perpendicular to the fiber direction is used as the scanning direction, which is convenient for observing the heating effect of the optical fiber on the target area in the cross-section, and the number of scanning layers is determined according to the target area, which is convenient for collecting intraoperative magnetic resonance images and timely and reasonably generating a three-dimensional temperature map.

[0175] Based on any of the above embodiments, in one embodiment, when the host runs the executable instruction, it also realizes:

[0176] S14. Generate a three-dimensional amplitude map according to the amplitude maps of the continuous magnetic resonance images, and determine whether the current magnetic resonance scanning range covers the target area according to the three-dimensional amplitude map. If not, re-determine the scanning parameters.

[0177] Specifically, the magnetic resonance device performs periodic image acquisition to update the monitoring data in real time. For each set of fast magnetic resonance scanning sequences, each amplitude map therein characterizes the structural information at the corresponding acquisition position. A three-dimensional amplitude map of the current period is reconstructed based on each amplitude map, and then it can be determined whether the current magnetic resonance scanning range covers the target area according to the three-dimensional amplitude map. It can be understood that the spatial range corresponding to the three-dimensional amplitude map is the current period's magnetic resonance scanning range. If the target area is not covered in the current magnetic resonance scanning range, it means that the target area cannot be comprehensively monitored, and the scanning parameters need to be re-determined.

[0178] In this embodiment, it is judged whether the patient has moved through the three-dimensional amplitude map. In the case of movement, the scanning parameters are re-adjusted so that the magnetic resonance scanning device can scan the target area and ensure the smooth progress of the operation.

[0179] Based on any of the above embodiments, in one embodiment, S14 includes:

[0180] Compare the background regions in the three-dimensional amplitude maps of the current period and the previous period. If the change in the cumulative gray value in the background region does not exceed the preset threshold, it is confirmed that the current magnetic resonance scanning range covers the target area; if it exceeds the preset threshold, further judgment is made. If the target area intersects with the boundary of the three-dimensional amplitude map, or the three-dimensional amplitude map does not contain the target area, it is determined that the current magnetic resonance scanning range does not cover the target area.

[0181] Specifically, the background region refers to the part of the target site that does not belong to the target area. The background region can be selected as the part of the target site that is outside the target area and has a certain distance margin from the target area to avoid the influence of optical fiber heating and heat conduction. The background region can also be preferably the skull region, and the gray level of the skull region in the magnetic resonance image basically does not change. Based on the skull region, it can be more accurately judged whether the patient has moved. The background region will not be heated during laser ablation, and the tissue structure will not change. Compare the background region in the three-dimensional amplitude map of the current period with the background region in the three-dimensional amplitude map of the previous period. If the difference in the cumulative gray values within the background region of the two is less than or equal to the preset threshold, it means that the patient has not moved and scanning can continue. If the difference is greater than the preset threshold, it means that the patient has moved, and it is necessary to further judge whether the target area is still within the current magnetic resonance scanning range after the patient moves; if it is judged that the target area intersects with the boundary of the three-dimensional structure diagram of the current period, it means that the patient has moved and part of the target area has exceeded the current magnetic resonance scanning range, and the scanning parameters need to be re-determined; if it is judged that the three-dimensional structure diagram of the current period does not contain the target area, it means that the patient has moved greatly and the current magnetic resonance scanning range cannot scan the target area, and the scanning parameters need to be re-determined.

[0182] For example, for each three-dimensional amplitude map, the background region of the current period is re-determined according to the target area range, and the determined background region is more accurate at this time. Another example of the determination method of the background region is that the background region of the current period is determined according to the background region of the previous period and its relative regional position in the three-dimensional amplitude map at the corresponding regional position in the three-dimensional amplitude map of the current period. In this case, the process of determining the background region is simpler and faster. The present invention does not limit the determination method of the background region for each period.

[0183] It can be understood that in the prior art, the heating effect of the optical fiber can only be monitored in several two-dimensional cross-sections perpendicular to the optical fiber direction. As long as the patient moves, it is necessary to re-perform a positioning sequence scan, re-determine the scan parameters, and obtain two-dimensional magnetic resonance images at the cross-section perpendicular to the optical fiber direction. In this embodiment, through the above process, it is possible to quickly and accurately determine whether the patient has moved and whether the movement has caused the target area to exceed the magnetic resonance scanning range. Since the present invention acquires and reconstructs a three-dimensional temperature map, the temperature data can be observed from any angle, direction, and cross-section. When the patient does not move or the movement does not exceed the magnetic resonance scanning range, it is not necessary to re-determine the scan parameters or perform a positioning sequence scan, which does not affect the normal progress of the laser ablation process.

[0184] Based on any of the above embodiments, in one embodiment, the re-determination of the scan parameters includes: if the target area intersects the boundary of the three-dimensional amplitude map of the current period, register the background regions of the three-dimensional amplitude maps of the current period and the previous period, and determine new scan parameters according to the registration relationship of the background regions.

[0185] Specifically, when the patient does not move, the background regions in the three-dimensional amplitude maps of the current period and the previous period directly correspond; when the patient moves, the magnetic resonance device scans a different body part from the previous period using the same scan parameters, that is, the background region in the three-dimensional amplitude map reconstructed in the current period does not directly correspond to the background region in the three-dimensional amplitude map of the previous period. Register the background region of the three-dimensional amplitude map of the current period with the background region of the three-dimensional amplitude map of the previous period so that the same tissue structure in the background region overlaps. The obtained registration relationship also corresponds to the "movement parameters" of the patient. According to this registration relationship, the scan parameters can be adjusted to determine new scan parameters.

[0186] In this embodiment, by matching the background regions of the three-dimensional amplitude maps of the current period and the previous period, new scan parameters are quickly and accurately determined according to the registration relationship, without re-performing a positioning sequence scan, which improves the efficiency of the laser ablation process.

[0187] Based on any of the above embodiments, in one embodiment, S14 includes: when the current three-dimensional amplitude map does not include the target area, registering the current three-dimensional amplitude map with the positioning three-dimensional structure diagram, and determining new scanning parameters according to the registration relationship between the current three-dimensional amplitude map and the positioning three-dimensional structure diagram.

[0188] Specifically, the fact that the current three-dimensional amplitude map does not include the target area means that the degree of patient movement is relatively large, and it is impossible to determine the scanning parameters based on the registration relationship between the current and previous three-dimensional amplitude maps. Since a large-scale positioning three-dimensional structure diagram has been established based on the positioning scan sequence before, registering the current three-dimensional amplitude map with the positioning three-dimensional structure diagram can indirectly determine the "movement situation" of the patient, thereby correcting the scanning parameters and determining new scanning parameters.

[0189] In this embodiment, when the degree of patient movement is large, by registering the current three-dimensional amplitude map with the positioning three-dimensional structure diagram, new scanning parameters are quickly determined, without the need to re-perform a large-scale and time-consuming positioning sequence scan, which shortens the operation time.

[0190] Based on any of the above embodiments, in one embodiment, when the host runs the continuous process, it also realizes:

[0191] According to the cross-section display instruction input by the user, display the corresponding cross-section effect in the fusion map of the three-dimensional temperature map and the preoperative three-dimensional image;

[0192] And / or, according to the cross-section adjustment instruction input by the user, adjust and display the corresponding cross-section effect in the fusion map of the three-dimensional temperature map and the preoperative three-dimensional image.

[0193] Specifically, the host also receives the instruction input by the user through an input device (such as a keyboard, mouse, touch screen, etc.), and after processing the magnetic resonance image data according to this instruction, it is displayed on the display device. The host can display the corresponding cross-section effect in the fusion map of the three-dimensional temperature map and the preoperative three-dimensional image according to the cross-section display instruction input by the user. For example, according to the cross-section determined by the user input instruction, the fusion map is divided into two parts (the part on the user observation side and the part on the non-user observation side), and the cross-section and the part of the three-dimensional structure diagram on the non-user observation side are displayed on the display device. Further, when the user places the operation cursor on the cross-section, the specific dimension value at the landing point can also be presented. The host can also adjust and display the corresponding cross-section effect in the fusion map of the three-dimensional temperature map and the preoperative three-dimensional image according to the cross-section adjustment instruction input by the user. The cross-section adjustment instruction is, for example, the rotation, translation, etc. of the cross-section.

[0194] In this embodiment, the magnetic resonance image data is processed according to the cross-section display / cross-section adjustment instruction input by the user, and the corresponding cross-section effect is displayed on the display device, facilitating the user to observe the temperature state at various positions and directions, evaluate the ablation state, and improving the accuracy and convenience of temperature monitoring.

[0195] In one embodiment based on any of the above, the host running the continuous also realizes:

[0196] Calculate the currently ablated area according to the three-dimensional temperature map, and display the currently ablated area in the preoperative three-dimensional image.

[0197] Specifically, tissues need to be maintained at different temperatures for different durations to reach the ablation state. For example, below 43°C, no ablation will occur no matter how long the heating is. When the temperature reaches above 43°C, the higher the temperature, the shorter the ablation time required. Determine the temperature and duration at each position according to the three-dimensional temperature map in each acquisition cycle, thereby judging whether the tissue at each position is ablated, determining the currently ablated area, and combining the registration relationship between the three-dimensional temperature map and the preoperative three-dimensional image, fuse and display the ablated area in the preoperative three-dimensional image. Preferably, display the ablated area transparently and blurred in the preoperative three-dimensional image.

[0198] The three-dimensional temperature map in this embodiment contains comprehensive and accurate temperature information, and the calculated currently ablated area is also more accurate. By displaying the currently ablated area in the preoperative three-dimensional image, it is convenient for the user to intuitively understand the position and size of the currently ablated area, and more accurately guide the laser ablation process.

[0199] In one embodiment based on any of the above embodiments, the host running the continuous also realizes:

[0200] In the next optical fiber ablation process, fuse the ablated area in the previous optical fiber ablation process into the current three-dimensional amplitude map of the current stage as the initial ablated area for the next optical fiber ablation process.

[0201] In the case of performing multi-fiber ablation in sequence, since it takes time to replace the optical fiber, there is a certain time interval between two ablation processes, and their temperature effects will not accumulate. However, the tissue degeneration of the ablated area is irreversible. The ablated area in the previous optical fiber ablation process can be fused into the current three-dimensional amplitude map of the current stage as the initial ablated area for this optical fiber ablation process to avoid repeated ablation of the ablated area.

[0202] There are various management methods for the "ablated area". For example, in the management method of the "ablated area", for each optical fiber ablation process, the ablation range occurring in this optical fiber ablation stage is managed separately, that is, the ablation area of each optical fiber ablation process is managed separately in this stage. In this case, for the next optical fiber ablation process, it is necessary to fuse the ablated areas in the previous optical fiber ablation processes into the three-dimensional amplitude map of the current stage as the initial ablated area of this optical fiber ablation process to provide a reference for this ablation process; Another management method of the "ablated area" is, for example, for each optical fiber ablation process, the cumulative ablated area during the ablation process (including the previous ablation areas and the ablation area of the current ablation process) is managed separately. In this case, only the cumulative ablated area of the previous ablation process needs to be fused into the three-dimensional amplitude map of the current stage as the initial ablated area of this optical fiber ablation process; Another management method of the "ablated area" is, for example, unified data management is adopted for each optical fiber ablation process, and the "ablated area" is updated in real time during each ablation process. In this case, only the "ablated area" needs to be fused into the three-dimensional amplitude map of the current stage as the initial ablated area of this optical fiber ablation process and updated. The present invention does not limit the data management method of the "ablated area", and only needs to provide the "initial ablated area" information reference for the next optical fiber ablation process.

[0203] In this embodiment, by fusing the ablated areas in the previous optical fiber ablation processes into the three-dimensional amplitude map of the current stage as the initial ablated area of the next optical fiber ablation process, it is convenient for users to observe the ablation state, and it avoids repeated ablation of the ablated tissue, improving the convenience and efficiency of ablation.

[0204] Based on any of the above embodiments, in one embodiment, the position of the target site is determined by a positioning sequence scan, and the positioning sequence scan image is an image obtained based on T1WI.

[0205] Specifically, the positioning sequence scan is to perform a magnetic resonance scan covering the target site for positioning the target site and determining the spatial positions of the target site and its target area. The positioning sequence scan can be based on T1WI imaging. T1 refers to the spin-lattice relaxation time (also known as the longitudinal relaxation time). T1WI is T1-weighted imaging, which means highlighting the longitudinal relaxation difference of tissues and minimizing the influence of other characteristics such as transverse relaxation on the image. Since within a certain temperature range, the T1 value has a linear relationship with the temperature, collecting T1WI for the target site can not only position the target site but also measure the initial temperature of the tissues therein.

[0206] In addition, the positioning sequence scanning image can also use imaging methods such as T2WI imaging and DWI imaging. T2 refers to the transverse duration, and T2WI means highlighting the transverse relaxation difference of tissues during the imaging process. DWI imaging refers to diffusion-weighted imaging.

[0207] In this embodiment, accurate positioning of the target site is performed through the positioning sequence scanning based on T1WI, which is convenient for determining the scanning parameters and providing guidance for the ablation of the target area.

[0208] Based on any of the above embodiments, in one embodiment, the magnetic resonance fast imaging sequence is an image obtained by scanning based on the gradient echo sequence.

[0209] Specifically, the purpose of using the magnetic resonance fast imaging sequence is to quickly acquire multi-layer magnetic resonance graphics under the condition of meeting the real-time requirement of temperature monitoring, so as to generate a three-dimensional temperature map with a resolution meeting the requirements. The gradient echo sequence scanning (FFE) has higher imaging efficiency than the spin echo sequence scanning. The spin echo tissue has a longer spontaneous relaxation time, and its TE (echo time) is longer, such as 10 - 15 ms, while the echo time of the gradient echo can be as short as 2 ms.

[0210] In addition, fast magnetic resonance scanning can also be achieved by shortening the repetition time TR, acquiring fewer phase encoding lines, using parallel acquisition technology, using gradient echo imaging, using EPI (echo planar imaging), PRESTO (gradient echo translation imaging), b-SSFP (balanced steady-state free precession imaging) sequence. The following briefly describes these fast magnetic resonance scanning methods:

[0211] Parallel acquisition technology: The parallel acquisition technology uses a multi-channel phased array coil to reduce the acquisition density of the K-space limited encoding lines, accelerate the acquisition speed of the magnetic resonance image, can shorten the image acquisition time by 1 - 16 times, increase the spatial resolution or increase the three-dimensional acquisition imaging range on the premise of unchanged acquisition time, and can also increase the number of repeated acquisitions to improve the image quality and reduce artifacts.

[0212] EPI (echo planar imaging): ERI is a special form of gradient echo. It uses a fast reverse gradient to generate a series of gradient echoes within a single relaxation time and performs phase encoding on them respectively, filling them into the corresponding K-space to achieve cross-sectional imaging.

[0213] PRESTO (gradient echo translation imaging): An additional negative gradient pulse is added to the gradient pulse sequence layer rotation gradient, and a positive gradient pulse with an equal area is given before the next excitation pulse. Then the gradient echo will be generated within the next TR time, which is equivalent to shifting the echo generated within the current TR time to the next TR time. This technology corrects the gradient echo translation, and the sequence name is called the PRESTO sequence.

[0214] b-SSFP (Balanced Steady-State Free Precession Imaging): When both the longitudinal magnetization vector and the transverse magnetization vector reach a steady state, this situation is called steady-state free precession. When reasonable TR, TE, and flip angles are set such that various echoes (FID, SE, and STE) generated by multiple radiofrequency pulses just merge into one echo, reaching a balanced state, this gradient echo sequence is called a balanced steady-state free precession sequence (b-SSFP). The signal collected by B-SSFP is the signal of the merged echoes, and its information density is higher.

[0215] In this embodiment, through the above specific fast magnetic resonance imaging method, magnetic resonance images are collected quickly and with high quality, which are used to reconstruct high-resolution three-dimensional temperature maps, providing sufficient information support for the laser ablation process.

[0216] The magnetic resonance three-dimensional temperature monitoring system provided by the present invention will be described below. The three-dimensional temperature monitoring system described below can be correspondingly referred to the three-dimensional temperature monitoring device described above.

[0217] Figure 2 It is a schematic structural diagram of a magnetic resonance-guided laser ablation system provided by the present invention, as Figure 2 shown. The system includes a magnetic resonance device 200, a laser ablation kit 300, and a magnetic resonance three-dimensional temperature monitoring device 100 as described in any one of the above.

[0218] Specifically, the magnetic resonance device 200 is used to collect magnetic resonance images of a patient and transmit them to the magnetic resonance three-dimensional temperature monitoring device 100. The magnetic resonance three-dimensional temperature monitoring device 100 processes the magnetic resonance images and displays relevant data through a display device. With the assistance of the display data output by the magnetic resonance three-dimensional temperature monitoring device 100, a doctor performs a laser ablation operation on the patient through the laser ablation kit 300.

[0219] Based on any one of the above embodiments, in one embodiment, the laser ablation kit 300 shown includes: a treatment light source module, a cooling circulation module, a cooling sleeve, and an ablation optical fiber.

[0220] Specifically, the treatment light source module is used to generate laser with the required power. The cooling circulation module is used to pump and recycle the coolant. The cooling sleeve is used to provide a circulation path for the coolant to cool the ablation optical fiber. The ablation optical fiber is used to introduce the laser into the target area to ablate the target area.

[0221] Furthermore, the laser ablation kit 300 may further include a temperature measurement module for measuring the temperature at the ablation site of the optical fiber, and the temperature measurement result can be mutually verified with the temperature result monitored by magnetic resonance.

[0222] Further, the laser ablation kit 300 may further include an optical fiber adjustment module for adjusting the depth of the optical fiber. When the ablation optical fiber is a directionally emitting optical fiber, the optical fiber adjustment module may be configured to adjust both the depth and the angle of the optical fiber.

[0223] The following describes the magnetic resonance three-dimensional temperature monitoring method provided by the present invention. The three-dimensional temperature monitoring method described below can be correspondingly referred to the three-dimensional temperature monitoring device described above.

[0224] Figure 3 is a schematic flowchart of the magnetic resonance three-dimensional temperature monitoring method provided by the present invention. As Figure 3 shown, the method includes:

[0225] S11. Obtain continuous magnetic resonance images covering the target area through fast magnetic resonance imaging;

[0226] S12. Generate a three-dimensional temperature map based on the continuous magnetic resonance images;

[0227] S13. Fusion-display the three-dimensional temperature map with the preoperative three-dimensional image.

[0228] In this embodiment, continuous magnetic resonance images covering the target area are efficiently obtained through fast magnetic resonance imaging for establishing a three-dimensional temperature map. Under the condition of meeting the real-time requirement, three-dimensional temperature data are obtained, which is convenient for the user to determine the temperature state at each position in the target area, making the temperature monitoring more comprehensive and the evaluation of the ablation state more accurate.

[0229] More embodiments of the magnetic resonance three-dimensional temperature monitoring method provided by the present invention can be correspondingly understood with reference to the embodiments of the three-dimensional temperature monitoring device provided above, and will not be elaborated here.

[0230] The following describes the magnetic resonance equipment scan parameter correction method provided by the present invention. This method is applied to magnetic resonance-guided laser interstitial thermotherapy. The magnetic resonance equipment scan parameter correction method described below can be correspondingly referred to the three-dimensional temperature monitoring device, magnetic resonance-guided laser ablation system, and magnetic resonance three-dimensional temperature monitoring method described above.

[0231] The magnetic resonance equipment scan parameter correction method provided by the present invention is applied to the host of the three-dimensional temperature monitoring device of the magnetic resonance, and is used to output corrected magnetic resonance equipment scan parameters according to magnetic resonance image data. Figure 4 is a schematic flowchart of the magnetic resonance equipment scan parameter correction method provided by the present invention. As Figure 4 shown, the method includes;

[0232] S41. Periodically perform fast magnetic resonance imaging on the target area, and obtain a set of continuous magnetic resonance images in each period;

[0233] Specifically, the magnetic resonance scanning device performs rapid magnetic resonance scanning on the target area periodically according to the scanning parameters. The host processes the scanned images to obtain a set of consecutive magnetic resonance images including the target area for the corresponding period. Here, "consecutive" means that the magnetic resonance scanning images of each layer are continuously adjacent, and there is no "missing area" between layers. Each set of magnetic resonance images can be used to establish a three-dimensional temperature map and a three-dimensional structure map for the current scanning period, facilitating real-time update of the monitoring data. Here, the rapid magnetic resonance imaging is a magnetic resonance imaging method that can efficiently collect data and be used to generate a three-dimensional temperature map. For example, a magnetic resonance imaging method that adopts means such as shortening the repetition time TR, collecting fewer phase encoding lines, using parallel acquisition technology, using an echo planar imaging sequence, using a gradient echo imaging sequence, using EPI, PRESTO, b-SSFP imaging sequence, etc. After the magnetic resonance device acquires the rapid magnetic resonance images, the host can receive and obtain the above data from the magnetic resonance device for data processing.

[0234] S42. For each set of magnetic resonance images, establish a three-dimensional temperature map based on the phase map in the magnetic resonance image and establish a three-dimensional amplitude map based on the amplitude map in the magnetic resonance image; wherein, the three-dimensional temperature map is used for fusion display with the preoperative three-dimensional image;

[0235] Specifically, each magnetic resonance image contains a phase map and an amplitude map. The amplitude map shows the tissue structure information at the corresponding section. The phase map can be used to generate the temperature map at the corresponding section. The phase maps in a set of magnetic resonance images can be used to establish the three-dimensional temperature map corresponding to this period, and then be fused with the preoperative three-dimensional image to display the temperature information at each position in the preoperative three-dimensional image (structural image), providing temperature information reference for the laser ablation process. The amplitude maps in a set of magnetic resonance images can be used to establish the three-dimensional amplitude map corresponding to this period.

[0236] S43. Compare the background regions in the three-dimensional amplitude maps of the current period and the previous period. If the change in the cumulative gray value in the background region is greater than the preset threshold, it is determined that the patient has moved, and the initial scanning parameters are corrected according to the registration relationship between the three-dimensional amplitude maps of the current period and the previous period to obtain new scanning parameters.

[0237] Specifically, the background region refers to the part of the target tissue that does not belong to the target area. The background region can be selected as the part of the target tissue that is outside the target area and has a certain distance margin from the target area to avoid the influence of fiber heating and heat conduction. The background region can also be preferably the skull region, and the gray level of the skull region in the magnetic resonance image basically does not change. Based on the judgment of the skull, it can be more accurately determined whether the patient has moved. The background region will not be heated during the laser ablation process, and the tissue structure will not change. Compare the background region in the current three-dimensional amplitude map with the background region in the previous three-dimensional amplitude map. If the difference in the cumulative gray value (i.e., the "change in the cumulative gray value" mentioned above) is greater than the preset threshold, it is determined that the patient has moved. At this time, register the current three-dimensional amplitude map with the previous three-dimensional amplitude map, and the obtained registration relationship represents the "patient's movement parameters". According to this registration relationship, correct the initial scan parameters to obtain new scan parameters.

[0238] In this embodiment, by obtaining the fast magnetic resonance sequence scanning images to establish a three-dimensional temperature map, under the condition of meeting the real-time requirement, three-dimensional temperature data is obtained, which is convenient for the user to determine the temperature state at each position of the target area, making the temperature monitoring more comprehensive and the evaluation of the ablation state more accurate. A three-dimensional amplitude map is also established based on the fast magnetic resonance sequence scanning images, and the scan parameters of the magnetic resonance device are corrected simply and quickly according to the three-dimensional amplitude map, solving the problem of being unable to accurately monitor the target area in the case of patient movement, and there is no need to repeat the time-consuming positioning sequence scanning, shortening the operation time.

[0239] Based on any of the above embodiments, in one embodiment, the method further includes:

[0240] S44. In the case where the current three-dimensional amplitude map and the previous three-dimensional amplitude map cannot be registered, register the current three-dimensional amplitude map with the positioning three-dimensional structure diagram, and determine new scan parameters according to the registration relationship between the current three-dimensional amplitude map and the positioning three-dimensional structure diagram; wherein, the positioning three-dimensional structure diagram is established according to the positioning scan sequence.

[0241] Specifically, the inability to register the current-phase and previous-phase three-dimensional amplitude maps indicates that the patient has moved significantly, and it is impossible to determine the scanning parameters based on the registration relationship between the current-phase and previous-phase three-dimensional amplitude maps. Before performing the fast magnetic resonance sequence scans for each phase, a localization sequence scan was first performed to determine the position of the patient's target area. Since the scanning range of this localization sequence scan is large enough to cover the target tissue (the target tissue is the biological tissue to be subjected to ablation operations, such as the liver, spleen, prostate, head, etc.), a localization three-dimensional structure diagram can be established based on the localization sequence scan images, which is used to determine the position of the target tissue and the position of the ablation target area contained in the target tissue. Since a localization sequence scan was first performed and a localization three-dimensional structure diagram was established before performing the fast magnetic resonance sequence scans for each phase, the current-phase three-dimensional amplitude map is three-dimensionally registered with the localization three-dimensional structure diagram, and the obtained registration relationship represents the "movement parameters" of the patient relative to when the localization sequence scan was performed, so that new scanning parameters can be determined.

[0242] In this embodiment, when the patient has moved significantly, by three-dimensionally registering the current-phase three-dimensional amplitude map with the localization three-dimensional structure diagram, new scanning parameters are quickly determined, and it is still not necessary to perform a large-scale and time-consuming localization sequence scan again, which shortens the operation time.

[0243] For more embodiments of the method for correcting scanning parameters of the magnetic resonance device provided by the present invention, reference can be made to the corresponding embodiments of the magnetic resonance three-dimensional temperature monitoring device, magnetic resonance-guided laser ablation system, and magnetic resonance three-dimensional temperature monitoring method described above, which will not be elaborated here.

[0244] Next, the ablation evaluation method of the magnetic resonance-guided laser interstitial thermotherapy system provided by the present invention will be described. The ablation evaluation method described below can be mutually corresponded and referred to with the magnetic resonance three-dimensional temperature monitoring device, magnetic resonance-guided laser ablation system, and magnetic resonance three-dimensional temperature monitoring method described above.

[0245] Specifically, the magnetic resonance-guided laser interstitial thermotherapy system includes a magnetic resonance device and a magnetic resonance three-dimensional temperature monitoring device. The ablation evaluation method of the magnetic resonance-guided laser interstitial thermotherapy system provided by the present invention is applied to the host of the magnetic resonance three-dimensional temperature monitoring device. Figure 5 It is a schematic flowchart of the ablation evaluation method of the magnetic resonance-guided laser interstitial thermotherapy system provided by the present invention. As Figure 5 shown, the method includes:

[0246] S51. Periodically perform fast magnetic resonance imaging on the target area, and obtain a set of continuous magnetic resonance images in each period;

[0247] During the intraoperative ablation process, we only focus on the temperature status of the target area and the surrounding tissues. There is no need to perform a global magnetic resonance scan covering the target tissue. The intraoperative magnetic resonance scan range that only covers the target area and the surrounding tissues is smaller than the scan range of the localization sequence scan. Therefore, the intraoperative magnetic resonance scan cycle can be shortened.

[0248] Specifically, the magnetic resonance device performs a rapid magnetic resonance scan on the target area according to the scan parameters, and periodically acquires rapid magnetic resonance sequence scan images. Among them, the image data acquired in each cycle contains a set of consecutive magnetic resonance images obtained by scanning the target area and the surrounding tissues. Here, consecutive means that the magnetic resonance scan images of each layer are continuously adjacent, and there is no "missing area" between layers. Each set of magnetic resonance images can be used to establish a three-dimensional temperature map and a three-dimensional structure map for the current scan cycle, which is convenient for real-time updating of the monitoring data. Here, the rapid magnetic resonance imaging is a magnetic resonance imaging method that can efficiently acquire and be used to generate a three-dimensional temperature map. For example, a magnetic resonance imaging method that takes measures such as shortening the repetition time TR, acquiring fewer phase-encoding lines, using parallel acquisition technology, using an echo-planar imaging sequence, using a gradient echo imaging sequence, using EPI, PRESTO, b-SSFP imaging sequence, etc.

[0249] S52. For each set of magnetic resonance images, establish a three-dimensional temperature map according to the phase map in the magnetic resonance images;

[0250] Specifically, by performing rapid magnetic resonance scans to acquire continuous thin-layer magnetic resonance images and establishing a three-dimensional temperature map based on this, the signal-to-noise ratio of the images can be improved, which is convenient for observing the temperature change situation in three-dimensional space, better guiding the ablation process, and evaluating the ablation status. Each magnetic resonance image contains a phase map and an amplitude map. The amplitude map shows the tissue structure information, and the phase map can be used to generate the temperature map of this layer. The phase maps in a set of magnetic resonance images can be used to establish the three-dimensional temperature map corresponding to this cycle.

[0251] S53. Judge the ablation status of the tissue according to the three-dimensional temperature maps of each period and the corresponding acquisition times.

[0252] Specifically, the temperature of the tissue and the duration of the temperature determine the ablation status of the tissue (that is, whether denaturation and necrosis occur). For example, when the temperature is lower than 43°C, the tissue will not be ablated no matter how long it lasts. Another example is that when the temperature is between 43°C and 45°C and lasts for more than 10 minutes, the tissue will be ablated. Another example is that when the temperature is between 50°C and 80°C, the tissue will be ablated in a short time. According to the three-dimensional temperature maps of each period and the corresponding acquisition times, determine the temperature status data of each voxel over time, and then use the evaluation model to evaluate the ablation status of each voxel. Preferably, the Arrhenius model or the CEM43 model is used to evaluate the ablation situation of each voxel.

[0253] In this embodiment, continuous magnetic resonance images covering the target area are efficiently obtained through fast magnetic resonance imaging for establishing a three-dimensional temperature map. Under the condition of meeting the real-time requirement, three-dimensional temperature data are obtained, which is convenient for the user to determine the temperature state at each position in the target area. Furthermore, the ablation state of the tissue is evaluated based on the three-dimensional temperature maps of each phase and the corresponding acquisition times. Compared with the evaluation in the two-dimensional section, the evaluation result is more accurate and comprehensive.

[0254] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or equivalently replace some of the technical features. However, such modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-dimensional magnetic resonance temperature monitoring device, characterized in that, Including: A host computer and a display device; the host computer stores executable instructions, and when the executable instructions are executed by the host computer, the following is achieved: Obtaining continuous magnetic resonance images covering the target area through fast magnetic resonance imaging; Generating a three-dimensional temperature map based on the continuous magnetic resonance images; Fusing and displaying the three-dimensional temperature map with the preoperative three-dimensional image.

2. The magnetic resonance three-dimensional temperature detection device according to claim 1, wherein, The obtaining of continuous magnetic resonance images covering the target area through fast magnetic resonance imaging includes: Determining a target area to be sampled in the current period according to a preset magnetic resonance downsampling rule; Performing magnetic resonance scanning on the target area to obtain a magnetic resonance image of the target area; Obtaining the continuous magnetic resonance images covering the target area in the current period through a reconstruction algorithm based on the magnetic resonance image of the target area.

3. The magnetic resonance three-dimensional temperature detection device according to claim 2, wherein The preset magnetic resonance downsampling rule is inter-slice downsampling and / or intra-slice downsampling.

4. The magnetic resonance three-dimensional temperature monitoring device according to claim 1, wherein The obtaining of continuous magnetic resonance images covering the target area through fast magnetic resonance imaging includes: Periodically scanning the target area through a magnetic resonance fast imaging sequence; Correcting the magnetic resonance image of the current period by using a reference period to obtain a corrected magnetic resonance image for generating the three-dimensional temperature map of the current period.

5. The three-dimensional magnetic resonance temperature monitoring device according to claim 4, wherein The reference period is a positioning sequence scan image obtained by pre-scanning a reference area, and the reference area covers the target area.

6. The three-dimensional magnetic resonance temperature monitoring device according to claim 5, characterized in that The magnetic resonance fast imaging sequence is a gradient echo sequence, and the positioning sequence is a spin echo sequence.

7. The magnetic resonance three-dimensional temperature monitoring device according to claim 4, characterized in that, The reference period is any corrected period, and the correcting of the magnetic resonance image of the current period by using the reference period includes: Obtaining distortion correction information according to the first position of the target tissue in the magnetic resonance image of the reference period and the second position of the target tissue in the magnetic resonance image of the reference period; wherein, the reference period is a positioning sequence scan image obtained by pre-scanning a reference area, and the reference area covers the target area; Correcting the magnetic resonance image of the current period according to the distortion correction information.

8. The magnetic resonance three-dimensional temperature monitoring device according to claim 1, characterized in that Before the obtaining of continuous magnetic resonance images covering the target area through fast magnetic resonance imaging, it includes: Obtaining a positioning sequence scan image, establishing a positioning three-dimensional structure diagram according to the positioning sequence scan image, and registering the positioning three-dimensional structure diagram with the preoperative three-dimensional image to determine the spatial position of the target area; wherein, the target area is outlined or automatically segmented in the preoperative three-dimensional image; Determining the scanning parameters of the fast magnetic resonance imaging according to the position of the target area, or determining the scanning parameters of the fast magnetic resonance imaging according to a user input instruction.

9. The magnetic resonance three-dimensional temperature monitoring device according to claim 8, wherein, Determining the scanning parameters of the fast magnetic resonance imaging according to the position of the target area includes: Taking the direction of the thinnest sandwich as the initial scanning direction according to the shape of the target area; wherein, the thinnest sandwich refers to two parallel planes that sandwich the target area with the smallest plane spacing.

10. The magnetic resonance three-dimensional temperature monitoring device according to claim 8, characterized in that, The determining of the scanning parameters of the fast magnetic resonance imaging according to the position of the target area includes: Taking the cross-section perpendicular to the optical fiber direction as the scanning direction; Determining the number of scanning layers according to the target area in the positioning three-dimensional structure diagram, or determining the number of scanning layers according to a user input instruction.

11. The three-dimensional magnetic resonance temperature monitoring device according to claim 1, characterized in that, The host running the executable instructions further implements: generating a three-dimensional amplitude map based on the amplitude maps of the consecutive magnetic resonance images, and determining whether the current magnetic resonance scanning range covers the target area according to the three-dimensional amplitude map. If not, re-determine the scanning parameters.

12. The three-dimensional magnetic resonance temperature monitoring device according to claim 11, wherein, The determination of whether the current magnetic resonance scanning range covers the target area includes: comparing the background regions in the three-dimensional amplitude maps of the current phase and the previous phase. If the change in the cumulative gray value in the background region does not exceed a preset threshold, it is confirmed that the current magnetic resonance scanning range covers the target area; if it exceeds the preset threshold, further judgment is made. If the boundary of the target area intersects with the three-dimensional amplitude map of the current phase, or the three-dimensional amplitude map of the current phase does not contain the target area, it is determined that the current magnetic resonance scanning range does not cover the target area.

13. The magnetic resonance three-dimensional temperature monitoring device according to claim 11, wherein The re-determination of the scanning parameters includes: registering the background regions of the three-dimensional amplitude maps of the current phase and the previous phase, and determining new scanning parameters according to the registration relationship of the background regions.

14. A magnetic resonance-guided laser ablation system, characterized in that, including: a magnetic resonance device, a laser ablation kit, and the magnetic resonance three-dimensional temperature monitoring device according to claims 1-13.

15. A magnetic resonance three-dimensional temperature monitoring method, including: obtaining consecutive magnetic resonance images covering the target area through fast magnetic resonance imaging; generating a three-dimensional temperature map according to the consecutive magnetic resonance images; fusing and displaying the three-dimensional temperature map with the preoperative three-dimensional image.

16. An ablation evaluation method for a magnetic resonance-guided laser interstitial thermotherapy system, characterized in that, including: periodically performing fast magnetic resonance imaging on the target area, and obtaining a set of consecutive magnetic resonance images in each period; for each set of magnetic resonance images, establishing a three-dimensional temperature map according to the phase map in the magnetic resonance images; judging the ablation state of the tissue according to the three-dimensional temperature maps of each phase and the corresponding acquisition times.

Images