基于振荡梯度自旋回波的扩散磁共振成像研究进展

Advances in diffusion MRI based on oscillating gradient spin echo

扩散磁共振成像(diffusion MRI,dMRI)是当前最有前景的生物组织微结构成像方法之一,在肿瘤、神经成像中取得了极大的进步。振荡梯度自旋回波(oscillating gradient spin echo,OGSE)序列是一种新型dMRI技术,它通过施加振荡梯度,使可测量的水分子有效扩散时间缩短,通过建立数学模型,可以测得细胞直径(diameter,d)、细胞外水分子扩散系数、细胞内水分子体积分数、细胞密度等微结构特征。在肿瘤细胞d值测量、肿瘤异质性评估、神经轴突直径测量中展现出临床应用前景。本文就OGSE的成像原理、OGSE在肿瘤和神经轴突中的研究现状及OGSE目前的限度进行综述,旨在为对该技术感兴趣的学者提供参考,推进OGSE的进一步研究,加速OGSE在临床诊疗中的应用进程。

Diffusion magnetic resonance imaging(dMRI)is one of the most promising methods for microstructural imaging of biological tissues,which has made great progress in tumor and neuroimaging.Oscillating gradient spin echo(OGSE)sequence is a new dMRI technique,which shortens the measurable effective diffusion time of water molecules by applying oscillating gradients.By establishing a mathematical model,the microstructure characteristics such as cell diameter,extracellular water molecular diffusion coefficient,intracellular water molecular volume fraction and cellularity can be measured.It shows the prospect of clinical application in tumor cell diameter measurement,tumor heterogeneity evaluation and nerve axon diameter measurement.This paper reviewed the imaging principle of OGSE,the research status of OGSE in tumors and nerve axons,and the current limitations of OGSE,aiming to provide reference for scholars interested in this technology,promote further research on OGSE,and accelerate the application of OGSE in clinical diagnosis and treatment.