阅读说明：本技术 一种针对髋关节脱位的磁共振t2定量成像和评估方法及系统 (Magnetic resonance T2 quantitative imaging and evaluation method and system for hip dislocation ) 是由 雷格格 周红艳 贾慧惠 吴继志 常严 冯洁 盛茂 杨晓冬 于 2020-06-29 设计创作，主要内容包括：本发明属于磁共振成像技术领域,本发明提供的磁共振T2定量成像和评估方法,包括构建髋关节软骨模体,自定义设置T2弛豫值；选出最优成像序列和最优扫描参数；基于最优成像序列和最优扫描参数,对比不同T2定量算法的精确度,得到最优T2定量拟合算法；对髋关节软骨进行分割,从而获得T2测量值分布和T2-mapping伪彩图,以此作为磁共振T2定量成像技术临床可行性的参考依据。该方法能够为髋关节软骨的T2定量成像提供最优成像序列及最优扫描参数组合,同时对比了不同T2定量算法的精度,为髋关节软骨的T2定量成像提供最优的定量算法和精度指标,为DDH的临床诊断提供髋关节各部分软骨的T2定量精度的参考依据。(The invention belongs to the technical field of magnetic resonance imaging, and provides a magnetic resonance T2 quantitative imaging and evaluation method, which comprises the steps of constructing a hip joint cartilage die body, and setting a T2 relaxation value in a self-defined manner; selecting an optimal imaging sequence and optimal scanning parameters; comparing the accuracy of different T2 quantitative algorithms based on the optimal imaging sequence and the optimal scanning parameters to obtain an optimal T2 quantitative fitting algorithm; segmenting the hip joint cartilage to obtain T2 measurement value distribution and a T2-mapping pseudocolor image, and taking the T2 measurement value distribution and the T2-mapping pseudocolor image as a reference basis for clinical feasibility of the magnetic resonance T2 quantitative imaging technology. The method can provide an optimal imaging sequence and an optimal scanning parameter combination for the T2 quantitative imaging of the hip joint cartilage, simultaneously compares the accuracy of different T2 quantitative algorithms, provides an optimal quantitative algorithm and accuracy index for the T2 quantitative imaging of the hip joint cartilage, and provides a reference basis for the T2 quantitative accuracy of each part of the hip joint cartilage for the clinical diagnosis of DDH.)

1. A method for quantitative imaging and evaluation of magnetic resonance T2 for hip dislocation, comprising the steps of:

firstly, constructing a hip joint cartilage die body, and setting a relaxation value T2 which accords with the hip joint cartilage in a self-defined manner;

secondly, selecting the T2 quantitative imaging pulse sequence with the minimum error with the T2 relaxation value from commonly used T2 quantitative imaging pulse sequences as an optimal imaging sequence through a simulation experiment based on the hip cartilage motif;

thirdly, performing parameter setting optimization on the optimal imaging sequence to obtain optimal scanning parameters;

fourthly, comparing the accuracy of different T2 quantitative algorithms based on the optimal imaging sequence and the optimal scanning parameters to obtain an optimal T2 quantitative fitting algorithm;

and fifthly, acquiring a gray image of the magnetic resonance T2-mapping pseudocolor image of the measured object by adopting the optimal imaging sequence, the optimal scanning parameters and the optimal T2 quantitative fitting algorithm, and segmenting the hip joint cartilage based on the gray image to obtain T2 measurement value distribution and a T2-mapping pseudocolor image which are used as reference basis for clinical feasibility of the magnetic resonance T2 quantitative imaging technology.

2. The quantitative magnetic resonance T2 imaging and evaluation method according to claim 1, wherein in the first step, the T2 value of the hip cartilage of the tested object is customized based on Spin-Scenario software library to obtain several data sets of T2 relaxation values.

3. The quantitative magnetic resonance T2 imaging and evaluation method according to claim 1 or 2, wherein in the second step, the step of selecting the optimal imaging sequence is:

writing code design is carried out on a plurality of T2 quantitative imaging pulse sequences based on a Spin-Scenario software library;

based on the T2 quantitative imaging pulse sequence designed by the written codes, and based on the hip joint cartilage motif, carrying out a magnetic resonance T2 quantitative imaging simulation experiment to obtain a series of echo images of the hip joint cartilage motif;

carrying out T2 quantitative fitting on pixel points of the echo image one by one to obtain a data set of a T2 calculated value of the hip joint cartilage motif;

comparing the T2 calculated value with the T2 relaxation value, and taking the T2 quantitative imaging pulse sequence with the minimum error as the optimal imaging sequence.

4. The quantitative magnetic resonance T2 imaging and evaluation method according to claim 1 or 2, wherein in the third step, parameters of the optimal imaging sequence are analyzed individually according to the principle of single variable control, other parameters and fitting method are kept unchanged, and exponential nonlinear fitting is used as the T2 quantitative fitting algorithm at this stage.

5. The quantitative magnetic resonance T2 imaging and evaluation method according to claim 4, wherein the parameters of the optimal imaging sequence are optimized in the order of echo image number optimization, echo time interval optimization of adjacent echo images, echo time optimization of the first image, and repetition time optimization.

6. The method for quantitative imaging and evaluation of magnetic resonance T2 according to claim 1 or 2, wherein the method for segmentation of hip cartilage comprises:

preprocessing the generated original magnetic resonance quantitative imaging;

extracting a boundary between the acetabular cartilage and the femoral head cartilage based on the gray-scale image of the magnetic resonance T2-mapping pseudocolor image;

and removing non-target objects according to the morphological characteristics of the hip joint cartilage, extracting a central circle of the femoral head based on Hough transformation, dividing areas of the acetabular cartilage and the femoral head cartilage by combining the extracted boundary, and generating binary images Mask and T2-mapping pseudo-color images of the acetabular cartilage and the femoral head cartilage.

7. The quantitative magnetic resonance T2 imaging and evaluation method of claim 6, wherein the preprocessing of the raw quantitative magnetic resonance imaging includes batch reading, DICOM file format conversion, ROI extraction, image noise processing and T2-mapping pseudocolor map generation.

8. The quantitative magnetic resonance T2 imaging and evaluating method according to claim 7, wherein two regions of acetabulum and femoral head are divided based on OTSU threshold segmentation algorithm, and edge detection is implemented by adaptive canny operator for extracting boundary lines of acetabulum cartilage and femoral head cartilage.

9. A magnetic resonance T2 quantitative assessment system providing a magnetic resonance T2 quantitative imaging and assessment method as claimed in any one of claims 1-8.

Technical Field

The invention belongs to the technical field of magnetic resonance imaging, and particularly relates to a magnetic resonance T2 quantitative imaging and evaluation method and system for hip dislocation.

Background

Magnetic Resonance Imaging (MRI) is a Nuclear Magnetic Resonance Imaging (NMRI) technique, also called Spin Imaging (Spin Imaging), which is a diagnostic technique that uses the Nuclear Magnetic Resonance phenomenon of a certain atomic nucleus in human tissue and reconstructs an image of a certain layer of the human body by processing the obtained radio frequency signal through an electronic computer. The magnetic resonance imaging technology can reflect various characteristics of tissues T1, T2, proton density and the like, and provides information for detection and diagnosis of diseases.

The traditional magnetic resonance imaging can only provide qualitative images with different contrasts, such as T1 weighting, T2 weighting, proton density weighting, diffusion weighting, magnetic sensitivity weighting and the like, and with the development of the magnetic resonance technology, the existing magnetic resonance imaging can also provide magnetic resonance quantitative information, and has more important significance for the evaluation of curative effect, the hierarchical diagnosis of diseases and the like.

Developmental Dislocation of Hip (DDH) is a common hip disease seriously threatening the healthy growth of children, and early treatment is found to remarkably reduce the harm of the disease to the human health and social development. The magnetic resonance quantitative imaging accurately measures the T2 value of cartilage to provide the change conditions of biochemical indexes such as collagen fiber arrangement, proteoglycan and water content related to the DDH early lesion, thereby realizing the early diagnosis and treatment planning of the DDH.

However, the current magnetic resonance quantitative imaging of DDH has the following problems in the clinical application process:

first, pulse sequences and settings of sequence parameters for magnetic resonance quantitative imaging of DDH lack a unified clinical scan standard. The contrast of the image has a great relationship with the pulse sequence and the sequence parameters used for scanning the image, and the images acquired on different devices or the images acquired on the same device in different hospitals have obvious difference on the tissue contrast, which affects the accuracy of the T2 quantitative imaging technology on clinical diagnosis.

Second, the existing quantitative imaging software platform lacks accuracy indexes. The quantitative imaging technology is mainly used for judging the tissue lesion condition according to T2 relaxation time, the accuracy of T2 value measurement can affect the clinical diagnosis effect of the quantitative imaging technology, and magnetic resonance scanners used in hospitals are all provided with post-processing workstations provided by manufacturers at present, basically aim at all tissues of the whole body, do not provide quantitative precision indexes of corresponding positions, and cannot provide accurate reference and basis for clinical diagnosis of DDH.

Third, there is no magnetic resonance image segmentation processing method for DDH at present. The accurate segmentation of the hip joint cartilage is the primary premise of the DDH accurate detection and evaluation, but because the acetabular cartilage is relatively thin and is not easy to distinguish in the magnetic resonance image, the current hip joint cartilage segmentation algorithms either aim at a specific sequence or have high requirements on the image quality or need to keep the stability of the hip joint geometric structure, and the algorithms are not completely suitable for the accurate segmentation of the DDH magnetic resonance image.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects that the pulse sequence and the sequence parameter setting of the magnetic resonance quantitative imaging of the existing DDH lack a unified clinical scanning standard, the magnetic resonance image can not be accurately segmented, and a quantitative imaging software platform lacks precision indexes.

In order to solve the technical problems, the invention adopts the technical scheme that:

the invention provides a magnetic resonance T2 quantitative imaging method for hip dislocation, which comprises the following steps:

firstly, constructing a hip joint cartilage die body, and setting a relaxation value T2 which accords with the hip joint cartilage in a self-defined manner;

secondly, selecting the common pulse sequence with the minimum error with the T2 relaxation value from common T2 quantitative imaging pulse sequences as an optimal imaging sequence through a simulation experiment based on the hip joint cartilage motif;

thirdly, performing parameter setting optimization on the optimal imaging sequence to obtain optimal scanning parameters;

fourthly, comparing the accuracy of different T2 quantitative algorithms based on the optimal imaging sequence and the optimal scanning parameters to obtain an optimal T2 quantitative fitting algorithm;

and fifthly, acquiring a gray image of the magnetic resonance T2-mapping pseudocolor image of the measured object by adopting the optimal imaging sequence, the optimal scanning parameters and the optimal T2 quantitative fitting algorithm, and segmenting the hip joint cartilage based on the gray image to obtain T2 measurement value distribution and a T2-mapping pseudocolor image which are used as reference basis for clinical feasibility of the magnetic resonance T2 quantitative imaging technology.

Preferably, in the magnetic resonance T2 quantitative imaging and evaluation method, in the first step, the T2 value of the hip cartilage of the tested object is set in a self-defining way based on a Spin-Scenario software library, and a plurality of data sets of T2 relaxation values are obtained.

Preferably, in the magnetic resonance T2 quantitative imaging and evaluation method, in the second step, the step of selecting the optimal imaging sequence is:

writing code design is carried out on a plurality of T2 quantitative imaging pulse sequences based on a Spin-Scenario software library;

based on the T2 quantitative imaging pulse sequence designed by the written codes, and based on the hip joint cartilage motif, carrying out a magnetic resonance T2 quantitative imaging simulation experiment to obtain a series of echo images of the hip joint cartilage motif;

carrying out T2 quantitative fitting on pixel points of the echo image one by one to obtain a data set of a T2 calculated value of the hip joint cartilage motif;

comparing the T2 calculated value with the T2 relaxation value, and taking the T2 quantitative imaging pulse sequence with the minimum error as the optimal imaging sequence.

Preferably, in the third step of the quantitative imaging and evaluation method of magnetic resonance T2, parameters of the optimal imaging sequence are analyzed individually according to a single variable control principle, other parameters and fitting methods are kept unchanged, and exponential nonlinear fitting is used as T2 quantitative fitting of the third step.

Further preferably, the magnetic resonance T2 quantitative imaging and evaluation method optimizes the parameter setting of the optimal imaging sequence by optimizing the number of echo images, optimizing the echo time interval of adjacent echo images, optimizing the echo time of the first image, and optimizing the repetition time.

Preferably, the magnetic resonance T2 quantitative imaging and evaluation method comprises the following steps:

preprocessing the generated original magnetic resonance quantitative imaging;

extracting a boundary between the acetabular cartilage and the femoral head cartilage based on the gray-scale image of the magnetic resonance T2-mapping pseudocolor image;

and removing non-target objects according to the morphological characteristics of the hip joint cartilage, extracting a central circle of the femoral head based on Hough transformation, dividing areas of the acetabular cartilage and the femoral head cartilage by combining the extracted boundary, and generating binary images Mask and T2-mapping pseudo-color images of the acetabular cartilage and the femoral head cartilage.

Further preferably, the magnetic resonance T2 quantitative imaging and evaluation method comprises preprocessing of the original magnetic resonance quantitative imaging including batch reading, DICOM file format conversion, ROI extraction, image noise processing and T2-mapping pseudocolor image generation.

Further preferably, the magnetic resonance T2 quantitative imaging and evaluation method divides an acetabulum and a femoral head area based on an OTSU threshold segmentation algorithm, and realizes edge detection through an adaptive canny operator, so as to extract boundary lines of an acetabulum cartilage and a femoral head cartilage.

The invention also provides a magnetic resonance T2 quantitative evaluation system capable of providing the magnetic resonance T2 quantitative imaging and evaluation method.

The technical scheme of the invention has the following advantages:

1. the invention provides a magnetic resonance T2 quantitative imaging and evaluation method for hip dislocation, which comprises the following steps: constructing a hip joint cartilage die body, and setting a relaxation value T2 which accords with the hip joint cartilage in a self-defined manner; secondly, selecting a T2 quantitative imaging pulse sequence with the minimum error with a T2 relaxation value from commonly used T2 quantitative imaging pulse sequences as an optimal imaging sequence through a simulation experiment based on a hip joint cartilage motif; thirdly, performing parameter setting optimization on the optimal imaging sequence to obtain optimal scanning parameters; fourthly, comparing the accuracy of different T2 quantitative algorithms based on the optimal imaging sequence and the optimal scanning parameters to obtain an optimal T2 quantitative fitting algorithm; and fifthly, acquiring a gray image of the magnetic resonance T2-mapping pseudocolor image of the measured object by adopting an optimal imaging sequence, an optimal scanning parameter and an optimal T2 quantitative fitting algorithm, and segmenting the hip cartilage based on the gray image to obtain T2 measurement value distribution and a T2-mapping pseudocolor image which are used as reference basis for clinical feasibility of the magnetic resonance T2 quantitative imaging technology.

The magnetic resonance T2 quantitative imaging and evaluation method for hip joint dislocation can provide an optimal imaging sequence and an optimal scanning parameter combination based on the optimal imaging sequence for the T2 quantitative imaging of hip joint cartilage, and simultaneously compares the accuracy of different T2 quantitative algorithms through a simulation experiment to provide an optimal quantitative algorithm and accuracy index for the T2 quantitative imaging of hip joint cartilage; when the magnetic resonance imaging of a DDH patient is subjected to postprocessing, the acetabulum cartilage and the femoral head cartilage can be accurately segmented, a reference basis of T2 quantitative accuracy of each part of cartilage of a hip joint is provided for clinical diagnosis of DDH, and accurate diagnosis of DDH is facilitated.

2. According to the magnetic resonance T2 quantitative imaging and evaluation method for hip dislocation, provided by the invention, a simulation experiment can set the hip cartilage die body with the T2 relaxation value in a user-defined manner according to needs, so that the problem that clinical data does not have a gold standard is well solved.

3. According to the magnetic resonance T2 quantitative imaging and evaluation method for hip dislocation, provided by the invention, the method for selecting the optimal imaging sequence can select the optimal imaging sequence from a plurality of commonly used T2 quantitative imaging pulse sequences, and is used for guiding the parameter setting of clinical magnetic resonance quantitative imaging.

4. The magnetic resonance T2 quantitative imaging and evaluation method for hip dislocation provided by the invention optimizes parameter setting of an optimal imaging sequence, optimizes the number of echo images, optimizes echo time intervals of adjacent echo images, optimizes echo time of a first image and optimizes repetition time by adopting a single contrast principle, obtains optimal scanning parameters, and transmits the optimal scanning parameters to a magnetic resonance scanner to guide parameter setting of clinical magnetic resonance quantitative imaging.

5. According to the magnetic resonance T2 quantitative imaging and evaluation method provided by the invention, the obtained hip joint cartilage Mask can be used for directly obtaining T2 measured value distribution of corresponding cartilage tissues and displaying a T2-mapping pseudo-color image, and can be used for counting and analyzing T2 relaxation time change conditions of cartilage.

6. The magnetic resonance T2 quantitative imaging and evaluation method provided by the invention can be used for coronary position imaging and different magnetic resonance sections such as sagittal position, cross section and the like, and because the used hip joint cartilage segmentation algorithm is based on a T2-mapping pseudo-color image to realize cartilage segmentation, the image quality requirement on the original magnetic resonance orientation imaging is not high, on the basis, the method not only can be used for cartilage segmentation of normal people, but also is suitable for DDH patients with hip joint dislocation or deformity, and the vacancy of the cartilage segmentation based on magnetic resonance imaging in the clinical application of cartilage malformation lesions such as DDH and the like is compensated to a certain extent.

7. According to the magnetic resonance T2 quantitative imaging and evaluation method provided by the invention, accurate T2 quantitative scheme evaluation is provided for clinical diagnosis of developmental hip dislocation of children from multiple aspects of pulse sequence selection, scanning parameter optimization, cartilage segmentation, T2 quantification and the like. The evaluation system may be operated in an off-line mode, i.e. run on a computer or workstation.

The optimal sequence information and quantitative method is completed by a computer or a workstation simulation platform in an analog simulation mode, the simulation result is transmitted to a hip joint post-processing software platform of a magnetic resonance image after the calculation is completed, magnetic resonance imaging parameters are set according to the provided optimal imaging scheme, clinical data of a patient are obtained and transmitted to the hip joint post-processing software platform, T2 quantification and cartilage segmentation are carried out on the hip joint of the patient, and the segmentation result is displayed on a screen for reference of a doctor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a flowchart of a magnetic resonance T2 quantitative imaging and evaluation method for hip dislocation provided in embodiment 1 of the present invention;

FIG. 2 is a graph illustrating the effect of different pulse sequences on the measurement accuracy of T2 according to embodiment 1 of the present invention;

FIG. 3 is a graph showing the quantitative accuracy of T2 for different echo counts provided in example 1 of the present invention;

FIG. 4 shows the T2 measurement results at different echo intervals provided by embodiment 1 of the present invention;

FIG. 5 shows the T2 measurements at various TE1 as provided in example 1 of the present invention;

FIG. 6 shows the T2 measurement error at different TRs provided by embodiment 1 of the present invention;

FIG. 7 is a flowchart of a hip cartilage segmentation algorithm provided in example 1 of the present invention;

FIG. 8 is a flowchart of an image pre-processing algorithm provided in embodiment 1 of the present invention;

fig. 9 is an extracted schematic view of a boundary line between an acetabulum and a femoral head provided in example 1 of the present invention;

fig. 10 is a schematic diagram of the segmentation of the acetabular cartilage and the femoral head cartilage provided in example 1 of the present invention;

FIG. 11 is a schematic view of the segmentation of the hip cartilage according to example 1 of the present invention;

FIG. 12 is a schematic view of the segmentation of normal hip cartilage according to example 1 of the present invention;

FIG. 13 is a schematic diagram of the segmentation of hip articular cartilage of DDH patients according to example 1 of the present invention;

fig. 14 is a schematic diagram of an evaluation system provided in embodiment 2 of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.