Quantitative T2* Magnetic Resonance Imaging for Iron Detection in Soft Tissue of the Fingers.

Abstract

T2* Magnetic Resonance Imaging (MRI) is an established method for the assessment of iron overload in multiple organs. Quantification of iron in the soft tissues of the fingers with T2* MRI could be of clinical value in conditions characterized by microvasculopathy. Herein, we examined the feasibility and repeatability of quantitative T2* MRI for the presence of iron in the soft tissues of fingers. In this prospective cohort study, 10 healthy individuals and three patients with digital microvasculopathy were subjected to hand MRI. Gradient echo (GRE) images with progressively increasing echo times (TE's) were acquired in a 1.5 T MRI system. After visual inspection of dual-colored maps of the hands, multiple regions of interest (ROIs) were placed in the soft tissues at areas that indicated increased susceptibility. Three ROIs per finger with the lowest T2* values (ms) were recorded. Mean T2* values for healthy individuals ranged from 12.5 to 16.0 ms (mean ± standard deviation [SD]: 14.0 ± 2.6 ms) except for a single ROI measurement of 8.8 ms in one individual. In contrast, multiple ROIs with T2* values below 8.8 ms were detected in the soft tissues of the three patients with digital microvasculopathy. The range of values for the three patients were (mean ± SD [range]: 7.4 ± 0.9 [5.2-8.8] ms, 7.9 ± 1.0 [5.9-10.3] ms, and 7.9 ± 1.7 [5.7-14.3] ms, respectively), suggestive of iron excess. Furthermore, 4/10 healthy individuals repeated the examination 1 year after the first MRI study. No areas with T2* below 8.8 ms were detected in the second study. In conclusion, T2* GRE is a feasible and reproducible technique for the quantification of iron in the soft tissues of the fingers.