Diffusion-Weighted Magnetic Resonance Imaging in Liver Graft Rejection

Objective: The purpose of this study is to evaluate the use of diffusion-weighted magnetic resonance imaging (DWMRI) in the assessment of graft rejection after liver transplantation (LT). Methods: From June 2017 to January 2018, 32 patients were included in the study with a mean age of 52.3 years. All patients underwent LT. The DWMRI was performed using the apparent diffusion coefficient map and measuring the different b-values (b-400, b-600, b-800, and b-1000). These measurements were compared with the histopathology results. Statistical analysis included t test, analysis of variance, and area under the curve for receiver operating characteristic (ROC). Results: There were 17 patients without rejection and 15 patients with liver graft rejection diagnosed by histopathology. The mean (SD) results between the nonrejection and rejection groups were as follows: b-400 = 1.568 (0.265) vs 1.519 (0.119) (P =.089), b-600 = 1.380 (0.181) vs 1.284 (0.106) (P =.039), b-800 = 1.262 (0.170) vs 1.170 (0.086) (P =.035), b-1000 = 1.109 (0.129) vs 1.098 (0.078) (P =.095); B-values × 10⁻³ mm²/s. Only b-600 (P =.04) and b-800 (P =.04) values have significant differences between the 2 groups. B-600 showed 90.48% sensitivity and 83.33% specificity (ROC area under the curve = 0.784; P <.001), and b-800 showed 90.38% sensitivity and 83.03% specificity (ROC area under the curve = 0.816; P <.001). The values obtained with the apparent diffusion coefficient in b-800 were clearly differentiated between the mild, moderate, and severe degrees of rejection (P <.001). Conclusion: Measurement of b-600 and b-800 values using DWMRI may be used for the diagnosis of graft rejection after LT.