Work

Field-cycling imaging yields repeatable brain R1 dispersion measurement at fields strengths below 0.2 Tesla with optimal fitting routine

Year: 2025

Type: article

Abstract: Objectives By rapidly changing magnetic field strength between 0.2 and 200 mT during the pulse sequence Field-Cycling Imaging (FCI) makes it possible to identify and evaluate new quantitative markers of pathology derived from dispersion of spin–lattice relaxation rate (R 1) in vivo. The aim of this work was to determine the most effective approach to reliably estimate multi-field R 1 dispersion measurements in brain tissue using FCI. Materials and methods This repeatability study consisted of twenty participants with moderate or severe small vessel disease. Each participant underwent 3 T MRI and FCI scans, repeated 30 days apart. After R 1 maps were generated at 0.2, 2, 20, and 200 mT, co-registered tissue labels generated from 3 T MRI were used to extract tissue averaged values of R 1 dispersion from regions of white matter (WM) and WM hyperintensities (WMHs). Results The fitted model which yielded best overall image contrast between WM and WMH regions and R 1 dispersion model adherence was determined. Tissue averaged values of R 1 (0.2 mT) and R 1 dispersion slope exhibited Cohen’s d effect sizes of 3.07 and 1.48, respectively, between regions of WM and WMH. The cohort study results were repeatable between study visits. Discussion Differences in R 1 measurements could repeatably be discerned between normal and abnormal appearing brain tissues.

Source: Magnetic Resonance Materials in Physics Biology and Medicine

DOI: 10.1007/s10334-025-01230-w