A Mixed Cohort, Multicentre Exploratory Study of Non-invasive Quantitative Assessment of Renal Graft Function With Non-contrast Functional Magnetic Resonance Imaging

This is a prospective, multicenter, hybrid cohort study designed to validate a non-contrast functional MRI protocol for the non-invasive, quantitative assessment of graft function in kidney transplant recipients. Primary Objectives: To establish an individualized functional baseline for transplanted kidneys through donor-recipient paired studies, moving beyond population-based reference values to enable a "self-comparison" paradigm for enhanced sensitivity in detecting early graft dysfunction. To validate the standalone capability of non-contrast functional MRI for sensitively monitoring dynamic changes in graft function in a large, independent cohort of recipients without donor baseline data (e.g., from deceased donors). To integrate MRI parameters with body composition analysis and metabolic profiles to build a comprehensive, non-invasive assessment model for early diagnosis, treatment evaluation, and prognosis prediction of graft function. Study Cohorts: Paired Study Cohort: Live or deceased kidney transplant donors who can undergo pre-transplant baseline MRI and their corresponding recipients. Independent Recipient Cohort: Kidney transplant recipients for whom donor baseline data is unavailable (primarily from deceased donors). Key Assessments: MRI Protocol: Includes multiple non-contrast functional sequences (e.g., DWI, ASL, BOLD, MT) to quantitatively evaluate renal perfusion, oxygenation, diffusion, and microstructure. Clinical \& Laboratory Data: Collection of serial serum creatinine, eGFR, uric acid, proteinuria, and other relevant biomarkers. Body Composition Analysis: MRI-based quantification of visceral, subcutaneous, perirenal, sinus renalis fat, and muscle mass. Histopathology: When available, biopsy results (e.g., rejection classification, fibrosis scores) will be collected as a reference standard. Study Procedures: Eligible participants will undergo non-contrast MRI scans at scheduled follow-up visits. Clinical data, laboratory results, and body composition metrics will be collected concurrently. For the paired cohort, donor baseline MRI (pre-transplant) serves as the individual reference. All data will be anonymized and analyzed to correlate MRI parameters with clinical, laboratory, and histopathological outcomes. Sample Size: The planned sample size is 1000 participants. This calculation is based on the inclusion of approximately 80 potential predictor variables (from MRI, clinical, and metabolic data) for multivariate analysis, requiring a sample size at least 10 times the number of variables, with an additional allowance for a 20% drop-out rate. Potential Impact: This study seeks to provide a novel, practical, and individualized solution for the precise monitoring of transplant kidney function, addressing a critical unmet need in clinical management, particularly for recipients of deceased donor organs.