Diagnostic and Prognostic Potential of Multiparametric Renal MRI in Kidney Transplant Patients

Abstract

BackgroundMultiparametric MRI provides assessment of functional and structural parameters in kidney allografts. It offers a non‐invasive alternative to the current reference standard of kidney biopsy.PurposeTo evaluate the diagnostic and prognostic utility of MRI parameters in the assessment of allograft function in the first 3‐months post‐transplantation.Study TypeProspective.Subjects32 transplant recipients (54 ± 17 years, 20 females), divided into two groups according to estimated glomerular filtration rate (eGFR) at 3‐months post‐transplantation: inferior graft function (IGF; eGFR<45 mL/min/1.73 m2, n = 10) and superior graft function (SGF; eGFR ≥ 45 mL/min/1.73 m2, n = 22). Further categorization was based on the need for hemodialysis (C1) and decrease in s‐creatinine (C2) at 1‐week post‐transplantation: delayed‐graft‐function (DGF: n = 4 C1, n = 10 C2) and early graft‐function (EGF: n = 28 C1, n = 22 C2).Field Strength/Sequence3‐T, pseudo‐continuous arterial spin labeling, T1‐mapping, and diffusion‐weighted imaging.AssessmentMultiparametric MRI was evaluated at 1‐week in all patients and 3‐months after transplantation in 28 patients. Renal blood flow (RBF), diffusion coefficients (ADC, ΔADC, D, D, D*, flowing fraction f), T1 and T1 were calculated in cortex and medulla. The diagnostic and prognostic value of these parameters, obtained at 3‐months and 1‐week post‐transplantation, respectively, was evaluated in the cortex to discriminate between DGF and EGF, and between SGF and IGF.Statistical TestsLogistic regression, receiver‐operating‐characteristics, area‐under‐the‐curve (AUC), confidence intervals (CIs), analysis‐of‐variance, t‐test, Wilcoxon‐Mann–Whitney test, Fisher's exact test, Pearson's correlation. P‐value<0.05 was considered significant.ResultsDGF patients exhibited significantly lower cortical RBF and f and higher D*. The diagnostic value of MRI for detecting DGF was excellent (AUC = 100%). Significant differences between patients with IGF and SGF were found in RBF, ∆T1, and ∆D. Multiparametric MRI showed higher diagnostic (AUC = 95.32%; CI: 88%–100%) and prognostic (AUC = 97.47%, CI: 92%–100%) values for detecting IGF than eGFR (AUC = 89.50%, CI: 79%–100%).Data ConclusionMultiparametric MRI may show high diagnostic and prognostic value in transplanted patients, yielding better results compared to eGFR measurements.Level of Evidence2Technical EfficacyStage 1