The role of magnetic resonance diffusion tensor imaging in differentiation of benign from malignant focal renal lesions

Abstract

Objectives: To determine the diagnostic performance of apparent diffusion coefficient (ADC) and fractional anisotropy (Fa) measurements in differentiation of malignant from benign focal renal lesions. Material and Methods: Twenty-one patients (9 women and 12 men; mean age 54,1 years) with 25 focal renal lesions diagnosed by different imaging modalities such as computed tomography (CT) and ultrasound (US) and examined with magnetic resonance diffusion tensor imaging (DTI) were included in the study. There were 6 solid renal cell carcinomas (RCC), 1 cystic RCC, 1 angiomyolipoma (AML) and 17 cystic lesions (16 Bosniak type I cysts, 1 Bosniak type II cyst). ADC and Fa measurements were performed by two radiologists, in consensus. The differences in ADC and Fa values of malignant and benign renal lesions were compared using ANOVA and Tukey tests. A ROC analysis was applied; sensitivities and specificities were calculated. Results: The mean ADC and Fa values of malignant lesions were 1.29 +/- 0.4 mm2/sec and 0.34 +/- 0.1, respectively. The mean ADC and Fa values of benign lesions were 2.6 +/- 0.7 mm2/sec and 0.19 +/- 0.12, respectively. The differences were significant (P<0.05). The Az values for discriminating malignant lesions from benign ones for ADC and Fa value were 0.95 and 0.83, respectively. The sensitivity-specificity of ADC and Fa were 100%-83.3%, and 100%-77.8%, respectively. Conclusion: There are statistically significant differences between ADC and Fa values of malignant and benign focal renal lesions. Malignant renal lesions have low ADCs and high Fa values, whereas benign renal lesions have high ADCs and low Fa values.