Insights into brain microstructure from in vivo DW-MRS

Neuroimage. 2018 Nov 15;182:97-116. doi: 10.1016/j.neuroimage.2017.11.028. Epub 2017 Nov 16.


Many developmental processes, such as plasticity and aging, or pathological processes such as neurological diseases are characterized by modulations of specific cellular types and their microstructures. Diffusion-weighted Magnetic Resonance Imaging (DW-MRI) is a powerful technique for probing microstructure, yet its information arises from the ubiquitous, non-specific water signal. By contrast, diffusion-weighted Magnetic Resonance Spectroscopy (DW-MRS) allows specific characterizations of tissues such as brain and muscle in vivo by quantifying the diffusion properties of MR-observable metabolites. Many brain metabolites are predominantly intracellular, and some of them are preferentially localized in specific brain cell populations, e.g., neurons and glia. Given the microstructural sensitivity of diffusion-encoding filters, investigation of metabolite diffusion properties using DW-MRS can thus provide exclusive cell and compartment-specific information. Furthermore, since many models and assumptions are used for quantification of water diffusion, metabolite diffusion may serve to generate a-priori information for model selection in DW-MRI. However, DW-MRS measurements are extremely challenging, from the acquisition to the accurate and correct analysis and quantification stages. In this review, we survey the state-of-the-art methods that have been developed for the robust acquisition, quantification and analysis of DW-MRS data and discuss the potential relevance of DW-MRS for elucidating brain microstructure in vivo. The review highlights that when accurate data on the diffusion of multiple metabolites is combined with accurate computational and geometrical modeling, DW-MRS can provide unique cell-specific information on the intracellular structure of brain tissue, in health and disease, which could serve as incentives for further application in vivo in human research and clinical MRI.

Keywords: (1)H magnetic resonance spectroscopy; Brain; Cell structure; Diffusion; Intracellular space; Metabolites; Tissue microstructure.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Brain* / anatomy & histology
  • Brain* / diagnostic imaging
  • Brain* / metabolism
  • Diffusion Magnetic Resonance Imaging / methods*
  • Humans
  • Proton Magnetic Resonance Spectroscopy / methods*