Diagnostic Contribution of Multiparametric Magnetic Resonance Imaging in Transplanted Kidneys: A Preliminary 3-Case Series.

Despite increasing interest in functional magnetic resonance imaging techniques, compartment-specific comparisons between donor kidneys and the same kidneys shortly after implant have remained limited. Therefore, in this preliminary case series, we aimed to explore early postoperative cortex- and medulla-specific multiparametric magnetic resonance imaging patterns in living-donor kidney transplant by directly comparing donor and recipient measurements within matched grafts. We assessed multiparametric magnetic resonance imaging parameters by comparing donor and early postoperative measurements acquired between postoperative days 19 and 23 in 3 transplant recipients. We categorized percent differences in parameters as stable, mild, moderate, or marked according to their magnitude; these classifications were descriptive. In analyses, donor-to-recipient variations were more pronounced in medullary parameters than in cortical measurements across all 3 grafts, and whole kidney values generally paralleled medullary behavior. Perfusion-related metrics, particularly pseudodiffusion and perfusion fraction, demonstrated the most prominent postoperative changes. In radar plots, donor kidneys displayed compact and overlapping medulla-to-cortex profiles, whereas transplanted kidneys showed expansion or distortion of medullary-dominant parameters, particularly in perfusion-related indices. These ratio-based visualizations emphasized redistribution toward medulla-driven physiological alterations in the early postoperative phase. The reproducible compartment-specific patterns observed in this series support the feasibility of multiparametric magnetic resonance imaging as a tool for early physiological monitoring after kidney transplant. Further validation in larger, longitudinal cohorts will be required to determine the clinical utility of corticomedullary metrics as potential biomarkers of early graft status.