One-stop blood vessel cavity and blood vessel wall imaging method

Abstract

The invention discloses a one-stop blood vessel cavity and blood vessel wall imaging method, which comprises the following steps: S1, injecting a bimodal blood pool contrast agent for shortening the relaxation time T1 and the relaxation time T2 of blood, collecting MR signals when water and fat are in the same phase in T1 weighting, and carrying out single-sequence one-stop imaging to obtain a first image; and S2, collecting T2 weighted MR signals, and obtaining a second image of black blood imaging. According to the invention, the bimodal blood pool contrast agent capable of shortening the T1 relaxation time and the T2 relaxation time at the same time is used, so that imaging with different weights can be conveniently carried out; water-fat in-phase imaging based on T1 weighting is preferentially carried out, the speed is high, and the efficiency is high; in addition, black blood imaging is carried out based on T2 weighting, a new contrast ratio is provided, interpretability is enhanced, and therefore the judgment accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vascular imaging, and in particular to a one-stop vascular lumen and vascular wall imaging method. Background Art

[0002] Since vascular diseases usually involve dual structural changes in the vascular lumen and vascular wall, comprehensive evaluation of the vascular lumen and vascular wall is essential for comprehensively monitoring the progression of related diseases and planning effective treatment strategies. Changes in the vascular lumen are usually manifested as changes in the inner diameter of the vascular lumen, such as lumen stenosis or occlusion caused by arteriosclerosis, or lumen dilation caused by aneurysms. Lesions of the vascular wall include intramural thrombosis, intimal thickening, plaque formation, fibrosis, calcification, etc.

[0003] MRI stands for magnetic resonance imaging, which means magnetic resonance imaging. With its advantages such as multi-sequence imaging capability and excellent soft tissue contrast, it has a unique and important position in the comprehensive evaluation of vascular cavities and vascular walls. Multi-sequence imaging capability means that MRI can obtain high spatial resolution images of vascular walls and vascular cavities through different pulse sequences, such as black blood imaging based on DIR double inversion recovery sequence and TSE fast spin echo sequence, and bright blood imaging based on TOF time-of-flight sequence and CE-MRA enhanced magnetic resonance angiography sequence, which helps to fully understand the characteristics of vascular lesions. At present, the solution for MRI to achieve comprehensive evaluation of vascular cavities and vascular walls is based on multi-sequence one-stop vascular cavity and vascular wall imaging, that is, through the combined scanning of the above multiple sequences, it is achieved in one MRI examination, that is, from the time the patient enters the MRI examination room to the time he leaves. In other words, the existing solution performs data acquisition and scanning of multiple sequences during one examination, one part of the sequence is intended to visualize the vascular cavity, and another part of the sequence is intended to visualize the vascular wall.

[0004] However, this type of clinical routine program cannot fully meet the complex clinical evaluation and measurement needs of vascular diseases. Taking the imaging evaluation before stent placement for abdominal aortic aneurysm endovascular repair as an example, although the existing one-stop multi-sequence imaging program can image the vascular lumen and vascular wall separately, different sequences and different scanning methods have different corresponding sequence types and acquisition methods. For example, some are 2D imaging acquisitions, while others are 3D imaging acquisitions. Different sequence acquisitions are likely to be incompatible. When using different sequence acquisitions, the differences in parameters such as spatial resolution, signal-to-noise ratio or contrast of different sequences must also be considered; at the same time, the differences in the patient's physiological state must also be considered. For example, the pulsatility of the abdominal aorta causes its morphology to change over time, which will bring registration errors and measurement inconsistencies to the comprehensive analysis of the vascular lumen and wall. In addition, the use of different sequence scans usually leads to longer examination time, which may cause discomfort to the patient during the examination and increase the probability of examination failure due to motion artifacts. In short, the key challenges of MRI-based preoperative planning for EVAR have not been effectively addressed. Accurate three-dimensional measurement of the outer diameter of the blood vessel, including the wall thickness, is required to select the appropriate size of the surgical stent, thereby ensuring that the stent can fit closely to the vessel wall and reduce the risk of endoleak.

[0005] In addition, the diseased vascular wall may have some complex components, such as newly attached mural thrombi, which puts higher technical requirements on one-stop imaging of the vascular lumen and vascular wall. The challenges are as follows: the contrast provided by a single sequence may not be able to effectively image the vascular lumen and vascular wall at the same time; most black blood techniques for visualizing the vascular wall rely on the blood flow state, resulting in low contrast between the vascular lumen and the vascular wall, especially the low contrast between the vascular lumen and the newly abnormal vascular wall in the hemodynamically abnormal segment, which may lead to false positive detection results; the individual interpretability of different sequences and their mutual interpretability are poor.

[0006] That is to say, the prior art includes at least the following three problems: 1) When different sequences are used for scanning and imaging, the different imaging methods, imaging parameters, and analysis methods of different sequences lead to long scanning time, registration errors, and inconsistent measurements during joint analysis; 2) When different sequences are used for scanning imaging, the individual interpretability of different sequences and the interpretability between them are poor, resulting in insufficient diagnostic consistency; 3) When only single-sequence scanning imaging is used, it is impossible to simultaneously image the vascular lumen and vascular wall in some complex lesions. Summary of the invention

[0007] In view of the above three problems, the purpose of the present invention is to propose a one-stop vascular lumen and vascular wall imaging method, which uses a dual-modality blood pool contrast agent that can simultaneously shorten the T1 relaxation time and the T2 relaxation time for injection, so as to facilitate subsequent different imaging based on the T1 relaxation time and the T2 relaxation time respectively; at the same time, priority is given to water-fat in-phase single sequence imaging based on T1 weighting, which has fast imaging speed and high efficiency, and is convenient for rapid clinical judgment of the patient's condition; then, black blood imaging can be performed in time based on T2 weighting to obtain a second image that is different from the first image principle, thereby providing new contrast, which can be mutually verified with the first image to improve the interpretability of the image, and can avoid factors that affect the poor imaging of the first image, so that when the first image is poorly imaged, the second image can be used as the basis for judging the condition; in addition, the first image and the second image can be fused to further improve the visualization effect and enhance the interpretability of the image.

[0008] This is achieved through the following technical solutions: A one-stop method for imaging a vascular lumen and a vascular wall, comprising the following steps: S1. injecting a dual-modality blood pool contrast agent capable of shortening the T1 relaxation time and T2 relaxation time of blood into a patient; collecting MR signals when water and fat are in the same phase under T1 weighting and performing single-sequence one-stop imaging using a first sequence to obtain a first image; S2. Acquire T2-weighted MR signals and obtain a second image of black blood imaging using a second sequence.

[0009] The dual-modality blood pool contrast agent that can shorten both T1 and T2 relaxation times is injected, so that different imaging can be performed based on T1 weighting and T2 weighting respectively. At the same time, water-lipid in-phase single sequence imaging based on T1 weighting is given priority, which has fast imaging speed and high efficiency. Then, black blood imaging is performed based on T2 weighting to compensate for the new method. The two images can also verify each other. Moreover, since the two imaging methods are different, the factors affecting the first image may not necessarily affect the second image. The second image can effectively serve as an auxiliary basis for disease diagnosis.

[0010] Optionally, in step S1, the dual-modality blood pool contrast agent is a contrast agent based on ferumoxytol superparamagnetic nano-iron oxide. The ferumoxytol superparamagnetic nano-iron oxide contrast agent can effectively shorten both the T1 relaxation time and the T2 relaxation time.

[0011] Optionally, the first sequence in step S1 is a LAVA Flex sequence, an mDIXON sequence, or a Dixon sequence. The LAVAFlex sequence, the mDIXON sequence, or the Dixon sequence can all be applicable to imaging of water-fat separation.

[0012] Optionally, in step S1, when acquiring MR signals when water and fat are in phase under T1 weighting, the echo time TE is first set, and the value of the echo time TE is adjusted until the protons of water and fat reach a synchronous state, and then the MR signal is acquired. The practice of first setting and adjusting TE to a phase synchronization state of water and fat protons can not only significantly improve image quality and diagnostic value, but also optimize the efficiency and flexibility of the entire imaging process.

[0013] Optionally, the second sequence in step S2 uses a T2-weighted spin echo sequence. The T2-weighted spin echo sequence is suitable for black blood imaging, requires a short scanning time and has a high contrast after imaging.

[0014] Optionally, the method further includes step S3: after obtaining the second image, fusing the second image with the first image to obtain a fused image showing the vascular cavity and the vascular wall. Fusion of images can further improve visualization effects, measurement accuracy, and enhance image interpretability.

[0015] Optionally, when fusing the second image with the first image, a fusion method adopts a rigid registration algorithm. The rigid registration algorithm is widely used and can effectively and simply fuse two images.

[0016] Optionally, the T2-weighted spin echo sequence used is an FSE sequence, a TSE sequence, or a HASTE sequence. The FSE sequence, the TSE sequence, or the HASTE sequence are all related MR imaging technologies based on the principle of spin echo sequences, and can effectively perform black blood imaging.

[0017] An electronic device is also proposed, comprising a memory and a processor, wherein the memory is used to store each instruction corresponding to any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods, and the processor is used to execute each instruction to implement any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods.

[0018] In addition, a readable storage medium is also proposed, and the readable storage medium is used to store each instruction corresponding to any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The technical solution of the present invention utilizes a dual-modality blood pool contrast agent that can simultaneously shorten the T1 relaxation time and the T2 relaxation time for injection, so as to facilitate subsequent different imaging based on the T1 relaxation time and the T2 relaxation time respectively; at the same time, priority is given to performing water-fat in-phase single sequence imaging based on T1 weighting, with fast imaging speed and high efficiency; then, black blood imaging can also be performed in a timely manner based on T2 weighting to obtain a second image that is different from the first image principle, thereby providing new contrast, which can be mutually verified with the first image to improve the interpretability of the image, and can avoid factors that affect the poor imaging of the first image, so that when the first image is poorly imaged, the second image can be used as the basis for judging the condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of a one-stop approach to imaging the vessel lumen and vessel wall; Figure 2 This is an imaging effect diagram of the first image after injection of ferumoxytol superparamagnetic nano iron oxide contrast agent; Figure 3 It is a MPR multi-planar reconstruction view and technology verification; Figure 4 This is a comparison of two images with enhanced T1 weighting and one image without enhanced T1 weighting after injection of ferumoxytol superparamagnetic nano iron oxide contrast agent; Figure 5 A comparison diagram of a first image and a second image in a one-stop vascular lumen and vascular wall imaging method. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0022] like Figure 1 The figure shows a flow chart of a one-stop vascular lumen and vascular wall imaging method, which preferentially performs T1-weighted single sequence imaging when water and fat are in phase, and can quickly complete imaging within a dozen seconds to a minute. Then, black blood imaging can be performed based on T2 weighting to provide new contrast, increase the interpretability of the image and perform auxiliary verification, thereby ensuring the accuracy of the patient's condition judgment. The method specifically includes the following steps: S1. Inject a dual-modality blood pool contrast agent that shortens the T1 relaxation time and T2 relaxation time of the blood into the patient, for example, a contrast agent based on ferumoxytol superparamagnetic nano-iron oxide, which can shorten both relaxation times at the same time. Then, collect MR signals when water and fat are in phase under T1 weighting and perform single-sequence one-stop imaging using the first sequence to obtain a first image.

[0023] It should be noted that after the injection of the contrast agent based on ferumoxytol superparamagnetic nano iron oxide, if T1-weighted imaging is performed first, the actual time taken is often between ten seconds and one minute; if T2-weighted imaging is performed first, the actual time taken is often between several minutes and ten minutes. Therefore, in order to speed up efficiency, especially when this scheme is used in medicine, in order to quickly obtain an imaging result, a single sequence one-stop imaging based on T1 weighting is performed first.

[0024] In this embodiment, the first sequence in step S1 can select LAVA Flex sequence, mDIXON sequence or Dixon sequence. LAVA Flex sequence is a flexible liver acquisition sequence with volume acceleration, which can perform 3D T1-weighted imaging, and then obtain a first image of water-fat separation in 3D; mDIXON sequence is a multi-point Dixon sequence, which accurately separates water-fat by acquiring images at different echo times TE, and obtains a high-precision first image; Dixon sequence is a Dixon sequence, which can also be used for imaging of water-fat separation.

[0025] In this embodiment, in step S1, when collecting MR signals when water and fat are in phase under T1 weighting, it is necessary to first set the echo time TE and the repetition time TR. The echo time TE and the repetition time TR are two key parameters in MRI imaging. In T1 weighted imaging, it is necessary to control the repetition time TR to be smaller, so as to improve the contrast and balance the acquisition time, so that the blood vessels or fat with a shorter T1 relaxation time appear brighter. The specific value of TR varies according to the performance of the machine actually used, generally within a few milliseconds to hundreds of milliseconds. The value of the echo time TE is adjusted to control the protons of water and fat to reach the same phase, which is considered to be a synchronous state. At this time, collecting MR signals again can improve the contrast and clarity of the imaging.

[0026] like Figure 2 The figure shows the first image after the injection of ferumoxytol superparamagnetic nano iron oxide contrast agent, which is used to verify the importance of signal acquisition when water and fat are in phase. The 1.81 cm and 1.93 cm in the figure are the lengths of the two blood vessel walls, respectively, and the endpoints both fall on the blood vessel wall. Figure 2 Figure A is the first image generated when water and fat are in phase. Figure 2 Figure B is the first image generated when water and fat are in different phases. Figure 2Figures C and D are comparison images of water and fat during MRI scans. It can be seen from the figures that in the first image corresponding to the same phase of water and fat, blood vessels are easier to distinguish from surrounding tissues, and the display effect is also very clear, which is easy to judge. If they are out of phase, the boundaries between blood vessels and surrounding tissues or organs in the generated image are unclear, and there are second-type chemical shift artifacts, which are prone to misjudgment.

[0027] S2. Acquire T2-weighted MR signals and obtain a second image of black blood imaging using a second sequence.

[0028] In this embodiment, the second sequence may adopt a spin echo sequence based on T2 weighting, which is suitable for black blood imaging, requires a short scanning time and has a high contrast after imaging. For example, an FSE sequence, a TSE sequence or a HASTE sequence may be adopted, wherein the FSE sequence is a Fast Spin Echo sequence; the TSE sequence is a Turbo Spin Echo sequence; and the HASTE sequence is a Half-Fourier Acquisition Single-shot Turbo Spin Echo sequence.

[0029] like Figure 5 As shown, a comparison diagram of a first image and a second image in a one-stop vascular lumen and vascular wall imaging method is used to verify the necessity of re-verifying with a second image with a different imaging principle when the first image is not clear enough. Figure 5 Figures A and C in the middle are the first two images of a specific part of the patient. Check the contrast between the vascular cavity and the vascular wall at the blue arrow. The contrast is obviously insufficient. The imaging of the target position in these two images is not clear enough. Correspondingly, Figure 5 Figures B and D are T2-weighted black blood images of the same location. As can be seen from the red arrows pointing to the target location in the figure, the boundary between the vascular lumen and the vascular wall is clearly revealed, with a clarity far exceeding that of the first image, which effectively compensates for the loss.

[0030] In addition, after obtaining the second image, step S3 can be performed: the second image and the first image are fused to obtain a fused image showing the vascular cavity and the vascular wall. For the first image and the second image obtained, both images can be 2D images or 3D images respectively. When performing image fusion, a rigid registration algorithm can be used for registration and fusion, so as to obtain a new image that is clearer and more interpretable after fusion. The rigid registration algorithm is a mature and widely used technology in the field of medical image processing and computer vision. This technology can be used to align two or more images for comparison, fusion or other forms of analysis.

[0031] like Figure 3The figure shows an MPR multi-planar reconstruction view and technology verification. The arrow is the target observation position. Figure 3 Figure A in the figure is an MPR multi-planar reconstruction view of a specific part of a patient, which is an imaging technique widely used in the field of medical imaging and is used here for comparison with the imaging of this scheme; Figure 3 Figure B is an imaging effect diagram of the same specific part of the patient using this scheme. This imaging effect diagram is obtained by fusion of the corresponding first image and second image using the LAVA Flex sequence as the first sequence and the DIR sequence as the second sequence after the injection of the ferumoxytol superparamagnetic nano-iron oxide contrast agent. The target observation position can be clearly seen, verifying the effectiveness of the fused image.

[0032] like Figure 4 Shown is a comparison of two images with enhanced T1 weighting and one image with non-enhanced T1 weighting after injection of ferumoxytol superparamagnetic nano-iron oxide contrast agent. Figure 4 Figures A and B in the middle are from another patient. Single-sequence imaging using this protocol continuously shows the bright vascular lumen and low-signal vascular wall from the upper edge of the liver to the common iliac bifurcation. Figure 4 Figure C is a non-enhanced T1-weighted in-phase image. Due to the poor contrast of the segment position as shown in the yellow cross in the figure, the visualization of the vascular wall is low. Figure 4 Figure D is a quantitative comparison of the vascular wall visualization length between the single-sequence imaging and non-enhanced T1-weighted in-phase images of this scheme. FE is the abbreviation of ferumoxytol Enhance, corresponding to enhanced T1; NE is the abbreviation of Non-Enhance, corresponding to non-enhanced T1; Distance of Aortic Vessel Wall Visualization indicates the clearly visible distance of the aortic vessel wall, and Imaging Technique indicates the imaging method.

[0033] An electronic device is also proposed, comprising a memory and a processor, wherein the memory is used to store each instruction corresponding to any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods, and the processor is used to execute each instruction to implement any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods.

[0034] In addition, a readable storage medium is also proposed, and the readable storage medium is used to store each instruction corresponding to any one of the above-mentioned one-stop vascular cavity and vascular wall imaging methods.

[0035] In summary, the present invention utilizes a dual-modality blood pool contrast agent that can simultaneously shorten the T1 relaxation time and the T2 relaxation time for injection, so as to facilitate subsequent different imaging based on the T1 relaxation time and the T2 relaxation time respectively; at the same time, priority is given to performing water-fat in-phase single sequence imaging based on T1 weighting, and the imaging speed is fast and the efficiency is high; then, black blood imaging can also be performed in a timely manner based on T2 weighting to obtain a second image that is different from the first image principle, thereby providing a new contrast, which can be mutually verified with the first image to improve the interpretability of the image, and can avoid the factors that affect the poor imaging of the first image, so that when the first image is poorly imaged, the second image can be used as the basis for judging the condition; in addition, the first image and the second image can be fused to further improve the visualization effect and enhance the interpretability of the image, which is significantly progressive.

[0036] The above embodiments are only for illustrating the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims

1. A one-stop vascular lumen and vascular wall imaging method, characterized in that: The steps include: S1. injecting a dual-modality blood pool contrast agent capable of shortening the T1 relaxation time and T2 relaxation time of blood into a patient; collecting MR signals when water and fat are in the same phase under T1 weighting and performing single-sequence one-stop imaging using a first sequence to obtain a first image; S2. Acquire T2-weighted MR signals and obtain a second image of black blood imaging using a second sequence.

2. A one-stop vascular lumen and vascular wall imaging method according to claim 1, characterized in that: In step S1, the dual-modality blood pool contrast agent is ferumoxytol superparamagnetic nano iron oxide contrast agent.

3. A one-stop vascular lumen and vascular wall imaging method according to claim 1, characterized in that: The first sequence in step S1 is a LAVA Flex sequence, an mDIXON sequence, or a Dixon sequence.

4. The one-stop vascular lumen and vascular wall imaging method according to claim 1, characterized in that: In step S1, when acquiring MR signals when water and fat are in phase under T1 weighting, the echo time TE is first set, and the value of the echo time TE is adjusted until the protons of water and the protons of fat reach a synchronous state, and then the MR signals are acquired.

5. The one-stop vascular lumen and vascular wall imaging method according to claim 1, characterized in that: The second sequence in step S2 uses a T2-weighted spin echo sequence.

6. The one-stop vascular lumen and vascular wall imaging method according to claim 1, characterized in that: The method further includes step S3: after obtaining the second image, fusing the second image with the first image to obtain a fused image showing the blood vessel cavity and the blood vessel wall.

7. A one-stop vascular lumen and vascular wall imaging method according to claim 6, characterized in that: When the second image is fused with the first image, a rigid registration algorithm is used as the fusion method.

8. The one-stop vascular lumen and vascular wall imaging method according to claim 5, characterized in that: The T2-weighted spin echo sequence used is FSE sequence, TSE sequence or HASTE sequence.

9. An electronic device, characterized in that: It comprises a memory and a processor, wherein the memory is used to store each instruction corresponding to the one-stop vascular cavity and vascular wall imaging method according to any one of claims 1-8, and the processor is used to execute each instruction to implement the method according to any one of claims 1-8.

10. A readable storage medium, characterized in that: The readable storage medium is used to store each instruction corresponding to the one-stop vascular lumen and vascular wall imaging method according to any one of claims 1-8.

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