CN-117084658-B - Magnetic resonance chemical exchange saturation transfer imaging method, system and equipment

CN117084658BCN 117084658 BCN117084658 BCN 117084658BCN-117084658-B

Abstract

The application discloses a magnetic resonance chemical exchange saturation transfer imaging method, a system, equipment and a storage medium, wherein the magnetic resonance chemical exchange saturation transfer imaging method comprises the steps of applying a radio frequency saturation pulse for a first preset time to a region to be detected; applying a radio frequency echo pulse to the region to be detected, and collecting a plurality of gradient echo signals generated after the radio frequency echo pulse is activated; and reading the plurality of gradient echo signals along a preset direction by utilizing a radial sampling mode so as to generate a magnetic resonance image. Through the mode, the application effectively shortens the signal acquisition time through the gradient echo reading, effectively inhibits the motion artifact through the radial acquisition mode, realizes the separation of the water and fat signals by applying post-processing modes such as fitting and the like to the acquired chemical exchange saturated transfer imaging spectrum data, and extracts and analyzes the target signal.

Inventors

ZHOU YANG
WEI PANPAN
ZOU CHAO
LIU XIN
ZHENG HAIRONG

Assignees

深圳先进技术研究院

Dates

Publication Date: 20260505
Application Date: 20220512

Claims (9)

1. A magnetic resonance chemical exchange saturation transfer imaging method, the magnetic resonance chemical exchange saturation transfer imaging method comprising: Applying a radio frequency saturation pulse for a first preset time to a region to be detected; applying a radio frequency echo pulse to the region to be detected, and collecting a plurality of gradient echo signals generated after the radio frequency echo pulse is activated; reading the plurality of gradient echo signals along a preset direction by utilizing a radial sampling mode so as to generate a magnetic resonance image; The signal attenuation models of the gradient echo signals are as follows: ; Wherein, the Representing echo time The intensity of the echo signal at the time of the time, N represents the number of echoes; Representing water signal intensity; Representing the signal intensity of fat, P representing the number of wave crest components of fat, the relative amplitude of each component being Satisfies the following conditions , Representing their corresponding chemical shifts; Is the local magnetization; Representing the chemical shift of the p-th fat peak component relative to water.
2. The method of claim 1, wherein the magnetic resonance chemical exchange saturation transfer imaging method, The number of radial sampling spokes in the radial sampling mode is 151, the first preset time is 50ms, and the number of gradient loops in each radial sampling is 6.
3. The magnetic resonance of claim 1 a chemical exchange saturation transfer imaging method, the method is characterized by further comprising the following steps of: Acquiring a plurality of magnetic resonance images of a plurality of gradient echo signals; Dividing a magnetic resonance water image and a magnetic resonance fat image from the plurality of magnetic resonance images by using a preset water-fat separation algorithm; and carrying out signal quantization by using the magnetic resonance water image, and acquiring concentration information based on a signal quantization result.
4. A magnetic resonance chemical exchange saturation transfer imaging method according to claim 3, wherein the pre-set water-fat separation algorithm is a self-checking field map estimation algorithm based on multi-resolution local growth.
5. The method of claim 3, wherein prior to said signal quantification using said magnetic resonance water image, said method further comprises: and responding to a user instruction, and selecting a region of interest corresponding to the user instruction from the magnetic resonance water image.
6. The method of magnetic resonance chemical exchange saturation transfer imaging of claim 5, The signal quantification using the magnetic resonance water image comprises: Acquiring a Z spectrum of pixel points in the region of interest based on the magnetic resonance water image; post-processing correction, symmetry analysis and multiple Chi Luolun Z fitting were performed on the Z spectra.
7. A magnetic resonance chemical exchange saturation transfer imaging system is characterized in that the magnetic resonance chemical exchange saturation transfer imaging system executes the magnetic resonance chemical exchange saturation transfer imaging method of any one of claims 1-6, and comprises a pulse module, an echo module and an imaging module, The pulse module is used for applying a radio frequency saturation pulse which lasts for a first preset time to the area to be detected; The echo module is used for applying radio frequency echo pulse to the region to be detected and collecting a plurality of gradient echo signals generated after the radio frequency echo pulse is activated; The imaging module is used for reading the plurality of gradient echo signals along a preset direction by utilizing a radial sampling mode so as to generate a magnetic resonance image.
8. A magnetic resonance chemical exchange saturation transfer imaging apparatus, characterized in that the magnetic resonance chemical exchange saturation transfer imaging apparatus comprises a memory and a processor coupled to the memory; The memory is used for storing program data, and the processor is used for executing the program data to realize the magnetic resonance chemical exchange saturation transfer imaging method according to any one of claims 1-6.
9. A computer storage medium for storing program data which, when executed by a computer, is adapted to carry out a magnetic resonance chemical exchange saturation transfer imaging method according to any one of claims 1 to 6.

Description

Magnetic resonance chemical exchange saturation transfer imaging method, system and equipment Technical Field The application relates to the technical field of magnetic resonance CEST imaging, in particular to a magnetic resonance chemical exchange saturation transfer imaging method, a system, equipment and a storage medium. Background The magnetic resonance CEST imaging method (Chemical exchange saturation transfer, CEST) was studied in 2000, and is rapidly gaining widespread attention due to its novel magnetic resonance contrast mechanism, becoming a completely new sensitive approach to study macromolecular chemical exchange and chemical kinetics. The principle is that a Radio Frequency (RF) pulse signal with a specific resonance frequency is selectively applied to saturate corresponding protons (shown in fig. 1 and pool B), and under a proper environment, the protons can chemically exchange with surrounding water molecules (shown in fig. 1 and pool A), so that partial saturation is transferred to the water molecules, and the CEST effect is reflected by detecting the reduction of the signal of the water molecules (shown in fig. 1). The chemical exchange process that occurs during the application of the saturation pulse allows the loss of proton signals to be significantly amplified, and therefore CEST contrast is more sensitive than directly observing these protons using magnetic resonance spectroscopy. Compared with other magnetic resonance contrast mechanisms, such as T1, T2, diffusion weighted imaging and other technologies, CEST can explore molecular targets containing exchangeable protons at a certain characteristic frequency, is very sensitive to metabolic substances and micro-environments in organisms, and is a unique molecular imaging means. Because the chemical exchange is closely related to the physiological environment of organism tissues, CEST can be used for imaging a plurality of important physiological parameters such as intracellular and extracellular acid-base balance, metabolic characteristics and the like, and plays a key role in detecting and evaluating various diseases such as metabolic disorder, tissue ischemia and the like. However, when performing abdominal CEST imaging, motion artifacts can be introduced into CEST images by human body motion (including respiration, involuntary movement, etc.), particularly when performing abdominal scanning, the consistency of K-space acquired data can be seriously damaged by respiratory motion, the reconstruction quality of magnetic resonance images is affected, and errors of CEST signal quantification are caused. Disclosure of Invention The application mainly provides a magnetic resonance chemical exchange saturation transfer imaging method, a system, equipment and a storage medium, which are used for solving the problems that the traditional magnetic resonance imaging method is easy to introduce motion artifacts, affects the reconstruction quality of magnetic resonance images and causes fat signals to interfere with CEST signal quantification. In order to solve the technical problems, the application adopts a technical scheme that a magnetic resonance chemical exchange saturation transfer imaging method is provided, and comprises the following steps: Applying a radio frequency saturation pulse for a first preset time to a region to be detected; applying a radio frequency echo pulse to the region to be detected, and collecting a plurality of gradient echo signals generated after the radio frequency echo pulse is activated; And reading the plurality of gradient echo signals along a preset direction by utilizing a radial sampling mode so as to generate a magnetic resonance image. According to an embodiment of the present application, the number of radial sampling spokes in the radial sampling manner is 151, the first preset time is 50ms, and the gradient echo beam of each radial sampling is 6. According to an embodiment of the present application, the signal attenuation models of the plurality of gradient echo signals are: Wherein S n represents the echo signal intensity at echo time TW n, n=1, 2, & gt, N is equal to or greater than 3, N represents the number of echoes, ρ ω represents the water signal intensity, ρ f represents the signal intensity of fat, P represents the number of peak components of fat, and the relative amplitudes of the components are α p, satisfying the requirements Indicating their corresponding chemical shift, f B =γΔb is the local magnetization, and f F,p indicates the chemical shift of the p-th fat peak component relative to water. According to an embodiment of the present application, the magnetic resonance chemical exchange saturation transfer imaging method further includes: Acquiring a plurality of magnetic resonance images of a plurality of gradient echo signals; Dividing a magnetic resonance water image and a magnetic resonance fat image from the plurality of magnetic resonance images by using a preset water-fat sepa