In vivo assessment of anisotropy of apparent magnetic susceptibility in white matter from a single orientation acquisition

NeuroImage

Daniel Güllmar¹  Jürgen R. Reichenbach²  Andreas Deistung³  Renat Sibgatulin³  Stefan Ropele⁴ 

[1] Corresponding author.;Department of Neurology, Medical University of Graz, Auenbruggerplatz 22, Graz 8036, Austria;Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital — Friedrich Schiller University Jena, Philosophenweg 3, Jena 07743, Germany;University Clinic and Outpatient Clinic for Radiology, Department for Radiation Medicine, University Hospital Halle (Saale), Ernst-Grube-Str. 40, Halle (Saale) 06120, Germany;

关键词: Quantitative susceptibility mapping;    R2*;    Orientation dependence;    White matter;    Anisotropy;    Tissue microstructure;   

DOI  :  

来源: DOAJ

【 摘 要 】

Multiple studies have reported a significant dependence of the effective transverse relaxation rate constant (R2*) and the phase of gradient-echo based (GRE) signal on the orientation of white matter fibres in the human brain. It has also been hypothesized that magnetic susceptibility, as obtained by single-orientation quantitative susceptibility mapping (QSM), exhibits such a dependence. In this study, we investigated this hypothesized relationship in a cohort of healthy volunteers. We show that R2* follows the predicted orientation dependence consistently across white matter regions, whereas the apparent magnetic susceptibility is related differently to fibre orientation across the brain and often in a complex non-monotonic manner. In addition, we explored the effect of fractional anisotropy measured by diffusion-weighted MRI on the strength of the orientation dependence and observed only a limited influence in many regions. However, with careful consideration of such an impact and the limitations imposed by the ill-posed nature of the dipole inversion process, it is possible to study magnetic susceptibility anisotropy in specific brain regions with a single orientation acquisition.

【 授权许可】

Unknown