Voxel-based mapping of five MR biomarkers in the wrist bone marrow

Objective MRI is a reliable and accurate technique to characterize rheumatoid arthritis. The aim of this study was to provide voxel-by-voxel 3D maps of the proton density fat fraction (PDFF), the T 1 of water ( T 1W ), the T 1 of fat ( T 1F ), the T 2 * of water ( T 2 * W ), the T 2 * of fat ( T 2 * F ) in the wrist bone marrow. Materials and methods The experiments were conducted on 14 healthy volunteers (mean age: 24 ± 4). The data were acquired at 1.5 T using two optimized four-echo 3D 1.2 × 1.2 × 1.2 mm 3 -isotropic spoiled gradient sequences. A repeatability study was carried out. The measurements were done using a homemade parametric viewer software. Results The inter-volunteer results were, on average: PDFF = 86 ± 3%, T 1W = 441 ± 113 ms, T 1F = 245 ± 19 ms, T 2 * W = 6 ± 1 ms and T 2 * F = 16 ± 3 ms. The coefficients of variation were for fat based biomarkers CV PDFF < 5%, CV T 1F < 15% and CV T 2*F < 10% in the repeatability study. Discussion The protocol and quantification tool proposed in this study provide high-resolution voxel-by-voxel 3D maps of five biomarkers in the wrist in less than 4 min of acquisition.