扩散核磁造影，全名水分子扩散核磁造影，是一种更进步的核磁共振技术。

1980年代中期扩散核磁造影的理论已被提出，1986年 Le Bihan 提出扩散磁振造影临床应用的潜在可能性。1990年Moseley的论文提到侦测猫的大脑局部缺血情况。1994年Basser推导出扩散张量磁振造影（Diffusion Tensor Imaging, DTI）的理论，2000年Wedeen成功发展扩散谱影像的技术。扩散核磁造影结合了PGSE测量扩散磁振信号与扩散磁振造影技术的概念，可应用于早期诊断缺血性脑中风，可以准确评估脑部、肝脏肿瘤的治疗效果。

Diffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is an imaging method that uses the Brownian motion of water molecules to generate contrast in MR images. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively. Molecular diffusion in tissues is not free, but reflects interactions with many obstacles, such as macromolecules, fibers, and membranes. Water molecule diffusion patterns can therefore reveal microscopic details about tissue architecture, either normal or in a diseased state. A special kind of DWI, diffusion tensor imaging (DTI), has been used extensively to map white matter tractography in the brain.