The Use of Diffusion Tensor Imaging in the Identification of Acute Rejection and Chronic Allograft Nephropathy After Renal Transplantation

Background Identifying the cause of renal allograft dysfunction is important for the clinical management of kidney transplant recipients. Purpose To evaluate the diagnostic efficiency of diffusion tensor imaging (DTI) for identifying allografts with acute rejection (AR) and chronic allograft nephropathy (CAN). Study Type Prospective. Subjects Seventy‐seven renal transplant patients (aged 42.5 ± 9.5 years), including 29 patients with well‐functioning stable allografts (Control group), 25 patients diagnosed with acute rejection (AR group), and 23 patients diagnosed with chronic allograft nephropathy (CAN group). Field Strength/Sequence 1.5 T/T2‐weighted imaging and DTI. Assessment The serum creatinine, proteinuria, pathologic results, and fractional anisotropy (FA) values were obtained and compared among the three groups. Statistical Test One‐way analysis of variance; correlation analysis; independent‐sample t ‐test; intraclass correlation coefficients and receiver operating characteristic curves. Statistical significance was set to a P ‐value <0.05. Results The AR and CAN groups presented with significantly elevated serum creatinine as compared with the Control group (191.8 ± 181.0 and 163.1 ± 115.8 μmol/L vs. 82.3 ± 20.9 μmol/L). FA decreased in AR group (cortical/medullary: 0.13 ± 0.02/0.31 ± 0.07) and CAN group (cortical/medullary: 0.11 ± 0.02/0.27 ± 0.06), compared with the Control group (cortical/medullary: 0.15 ± 0.02/0.35 ± 0.05). Cortical FA in the AR group was higher than in the CAN group. The area under the curve (AUC) for identifying AR from normal allografts was 0.756 and 0.744 by cortical FA and medullary FA, respectively. The AUC of cortical FA and medullary FA for differentiating CAN from normal allografts was 0.907 and 0.830, respectively. The AUC of cortical FA and medullary FA for distinguishing AR and CAN from normal allografts was 0.828 and 0.785, respectively. Cortical FA was able to distinguish between AR and CAN with an AUC of 0.728. Data Conclusion DTI was able to detect patients with dysfunctional allografts. Cortical FA can further distinguish between AR and CAN. Evidence Level 2 Technical Efficacy Stage 2