Combined diffusion-relaxometry microstructure imaging: Current status and future prospects

Microstructure imaging seeks to noninvasively measure and map microscopic tissue features by pairing mathematical modeling with tailored MRI protocols. This article reviews an emerging paradigm that has the potential to provide a more detailed assessment of tissue microstructure-combined diffusion-relaxometry imaging. Combined diffusion-relaxometry acquisitions vary multiple MR contrast encodings-such as b-value, gradient direction, inversion time, and echo time-in a multidimensional acquisition space. When paired with suitable analysis techniques, this enables quantification of correlations and coupling between multiple MR parameters-such as diffusivity, T-1, T-2, and T-2*. This opens the possibility of disentangling multiple tissue compartments (within voxels) that are indistinguishable with single-contrast scans, enabling a new generation of microstructural maps with improved biological sensitivity and specificity.

Automated summary

This article discusses an emerging paradigm in microstructure imaging that combines diffusion-relaxometry imaging to provide a more detailed assessment of tissue microstructure. By varying multiple MR contrast encodings in a multidimensional acquisition space, correlations and coupling between multiple MR parameters can be quantified, enabling the disentangling of multiple tissue compartments within voxels. This allows for the creation of new generation microstructural maps with improved biological sensitivity and specificity.