Speaker
Description
University Bern, MR Methodology, Departments of Radiology and Biomedical Research, Bern, CH
Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, D
Diffusion-weighting is well established as clinical tool in MRI and as a valuable research tool for the investigation of fiber and micro-structure. Diffusion weighted MR spectroscopy (DW MRS) [1,2] is also becoming more and more of interest to investigate brain microstructure in vivo. The paramount advantage compared to DW water imaging lies with the fact that diffusing metabolites exclusively and selectively probe intracellular space, while DW MRI is complicated by fast intra/extracellular exchange.
In this contribution, we report on two quite distinct aims in the context of DW MRS:
1st we developed DW MR methods to gain microstructural information, where we have extended the range of exploitable diffusion times on clinical systems to a much shorter temporal regime using oscillating gradients [3,4].
2nd we currently use ultra-strong diffusion gradients and interrelated data modeling to help define the macromolecular (MM) signals [5] encountered in clinical short echo-time spectroscopy, where they overlap with the spectral components of small mobile metabolites and hinder the precision of their evaluation if the MM signals are not well defined and have to be represented with flexible or inaccurate models.
References
1. Ronen I, Valette J. Diffusion-Weighted Magnetic Resonance Spectroscopy. eMagRes: John Wiley & Sons, Ltd; 2015:733-750.
2. Palombo M, Shemesh N, Ronen I, Valette J. Insights into brain microstructure from in vivo DW-MRS. NeuroImage. 2018;182:97-116.
3. Doring A, Adalid V, Boesch C, Kreis R. Diffusion-weighted magnetic resonance spectroscopy boosted by simultaneously acquired water reference signals. Magn Reson Med. 2018;80(6):2326-2338.
4. Doring A, Kreis R. Magnetic resonance spectroscopy extended by oscillating diffusion gradients: Cell-specific anomalous diffusion as a probe for tissue microstructure in human brain. Neuroimage. 2019;202:116075.
5. Kunz N, Cudalbu C, Mlynarik V, Huppi PS, Sizonenko SV, Gruetter R. Diffusion-weighted spectroscopy: A novel approach to determine macromolecule resonances in short-echo time (1)H-MRS. Magn Reson Med. 2010;64:939-946.
