The diagnostic efficacy of multiparametric MRİ in determining subtypes of renal cell cancer

Purpose: The aim of this study is to evaluate the diagnostic efficiency of multiparametric MRI in differentiation of common subtypes of renal cell cancer (RCC) by using conventional T2-weighted images, dynamic contrast-enhanced MRI and ADC values. Materials and Methods: Ninety-eight tumors (mean tumor diameter, 4 cm) of 59 clear cell type, 29 papillary cell type and 10 chromophobe type renal cell cancers in 91 patients (18 female, 73 male; age range, 18-85 years; mean age 61.8 years) who were operated for renal cell cancer and had pre-operative contrast enhanced upper abdomen MRI were included in our study. In the axial plane, DWI sequences, T2-weighted sequences, pre-contrast T1-weighted sequence and after contrast T1-weighted sequences in three phases (corticomedullary phase, nephrographic phase, excretory phase) were obtained. Region of interest measurements within uninvolved renal parenchyma and tumor were used to calculate signal intensity change percentage, tumor-cortex contrast index, contrast washout rate, apperent diffusion coefficient (ADC) value of the tumor, tumor-cortex ADC ratio and qualitive T2 scoring. In order to distinguish clear cell RCC from non-clear cell RCCs, ROC (receiver operating characretistics) analysis was used to determine the cutting points of the radiological parameters and the area under the curve, sensitivity and specificity values were calculated. The level of significance was determined as p<0,05. Findings: In differentiating clear cell RCC from non-clear cell RCC, the sensitivity of corticomedullary phase signal intensity change was 78%, specificity 88% (AUC 0.88, cut-off point> 130.6%), sensitivity of tumor-cortex enhancement index was 86%, and specificity 82% (AUC 0.89, cut-off point> 0.52), sensitivity of tumor ADC value 81% and specificity 90% (AUC 0.92, cutoff point> 1.14), sensitivity of ADC ratio 80% and specificity 87% (AUC 0.91, cut-off point> 0.61), the sensitivity of the washout rate was 76%, and the specificity was 70% (AUC 0.72, cut-off point> 5.82%). It was shown that there is a statistically significant, high level of agreement between the T2 score and the presence of clear cell RCC in pathological evaluation (Cramer's V=0,762, p<0,001). Conclusion: Clear cell, papillary and chromophobe RCCs demonstrate different enhancement patterns on dynamic contrast-enhanced MR images as well as specific diffusion and T2 signal characteristics. We think that the diagnostic sensitivity and specificity of the use of multiparametric MRI, which consists of components including the T2 scoring system and ADC ratio used in our study, is high in distinguishing the most common subtypes of RCC