Zhejiang University

Ruiliang Bai

Guangxu Han

Zejun Wang

Fan Jiang

Yingchao Liu

Xinyu Jin

Yinhang Jia

Zhaowei Cheng

Zhaoqing Li

The present invention discloses a diffusion magnetic resonance (MR) method for measuring arterial pulsation dependence of perivascular cerebrospinal fluid flow in glymphatic system: DTI acquisition: Brain MRI images were acquired using dynamic diffusion tensor imaging (DTI); Cardiac signal synchronization: Simultaneously collect heart rate fluctuation time-series signals; Peak coordinate determination: Identify the peak timing of cardiac pulsation signals from the time-series data; Image realignment: Reorganize brain MR images according to their temporal positions within the cardiac cycle; Temporal interpolation: Perform uniform time-sampling reconstruction to generate equidistant diffusion MRI datasets across the cardiac cycle; Parameter calculation: Compute axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) at each voxel level; Mask-based analysis: Generate characteristic curves of AD/RD/MD and spin density(S) dynamics using region-specific masks in individual space. This method enables non-invasive measurement of: (1) Cerebrospinal fluid (CSF) flow velocity/direction in large perivascular spaces during heartbeats; (2) Microvascular perivascular CSF dynamics through diffusion parameter analysis.

Diffusion magnetic resonance method for measuring cardiac-cycle-dependent glymphatic system circulation

This invention discloses a method for quantitatively measuring the water exchange rate across myelin sheath. The method involves the following steps: acquiring images using the FEXI sequence; identifying anisotropic regions and the orientation of neural fibers at each pixel within these regions; selecting images where the diffusion weighted directions are perpendicular to the orientation of neural fibers at each pixel within the anisotropic regions and numerically averaging the selected images; calculating the apparent exchange rate (AXR), the apparent diffusion coefficient (ADC), and the filter coefficient (σ) using the numerically averaged images, where AXR serves as a specific parameter reflecting the water exchange rate across myelin sheath. The method provided by this invention enables specific detection of the exchange process of water molecules inside and outside the myelin sheath and analysis of the apparent water exchange rate across myelin sheath.

Method for quantitatively measuring the water exchange rate across myelin sheath in brain white matter

The present invention discloses the cross-domain network method for magnetic resonance imaging undersampling trajectory optimization in Fourier domain and reconstruction network in image domain. The method includes the following steps: obtaining a head MR image, preprocessing, and obtaining simulated fully sampled k-space data through Fourier Transform; separating the real and imaginary parts of the simulated fully sampled k-space data and independently storing them in two matrices with the same dimensions, then merging them into two channels as inputs to the cross-domain network; constructing the cross-domain network, including the undersampling layer, the Inverse Fourier Transform layer, and the reconstruction network; training the cross-domain network until convergence; using the trained network to acquire and reconstruct the head MR image.

Cross-domain network based magnetic resonance imaging undersampling pattern optimization and reconstruction method

The invention discloses a method for measuring the intracellular water transmembrane efflux rate (k): setting magnetic resonance imaging parameters and measuring the noise level during scanning. Optimizing the flip angle and resetting it through Monte Carlo simulation. Scanning quantitative T1 imaging. Scanning dynamic-contrast-enhanced magnetic resonance imaging and injecting contrast agent. The full shutter speed model (SSM) is used to analyze every voxel in the tumor area and obtain the kof them. This method significantly improves the accuracy of k. The invention discloses the measuring method, system and application of kas a magnetic resonance imaging biomarker of glioma, which is not for disease diagnosis, to evaluate the expression level of AQP4. The invention discloses the application of kas a magnetic resonance imaging marker of glioma in the preparation of a product for predicting the sensitivity of glioma radiotherapy and chemotherapy. Through the above methods, systems and applications, the non-invasive and quantitative measurement and imaging of AQP4 expression level in glioma have been realized.

Method and application for measuring the intracellular water transmembrane efflux rate, and measurement method and system for magnetic resonance imaging biomarker of glioma

The present invention discloses an analysis method for dynamic contrast-enhanced magnetic resonance image. Firstly, the time-series signal of vascular contrast agent concentration, AIF, of biological individual is obtained from DCE-MRI time-series data. Secondly, perform the nonlinear least sum of square fitting by using the full Shutter-Speed model (SSM) and the simplified vascular Shutter-Speed model (SSM) on the DCE-MRI time-series signal of each pixel, and the fitting results of DCE-MRI time-series signal are obtained. Thirdly, the corrected Akaike Information Criterion (AIC) score is used to comparing the DCE-MRI time-series signal fitting results to select the optimal model. If the optimal model is SSM, distribution maps of five physiological parameters. K, pp, k, and k, are produced after fitting; if the optimal model is SSM, distribution maps of three physiological parameters, K, p, and k, are produced after fitting. Finally, perform error analysis on the kand k, resulting the final distribution maps of kand kalong with distribution maps of parameters K, p, p. This method can improve the estimation accuracy of K, p, p, kand k.

Growing community of inventors

Hangzhou, China

Ruiliang Bai