Improvements in Between-Vendor MRI Harmonization of Renal T 2 Mapping using Stimulated Echo Compensation

T mapping is valuable to evaluate pathophysiology in kidney disease. However, variations in T relaxation time measurements across MR scanners and vendors may occur requiring additional correction. To harmonize renal T measurements between MR vendor platforms, and use an extended-phase-graph-based fitting method ("StimFit") to correct stimulated echoes and reduce between-vendor variations. Prospective. 8 healthy "travelling" volunteers (37.5% female, 32 ± 6 years) imaged on four MRI systems across three vendors at four sites, 10 healthy volunteers (50% female, 32 ± 8 years) scanned multiple times on a given MR scanner for repeatability evaluation. ISMRM/NIST system phantom scanned for evaluation of T accuracy. 3T, multiecho spin-echo sequence. T images fit using conventional monoexponential fitting and "StimFit." Mean absolute percentage error (MAPE) of phantom measurements with reference T values. Average cortex and medulla T values compared between MR vendors, with masks obtained from T -weighted images and T maps. Full-width-at-half-maximum (FWHM) T distributions to evaluate local homogeneity of measurements. Coefficient of variation (CV), linear mixed-effects model, analysis of variance, student's t-tests, Bland-Altman plots, P-value