Quantitative evaluation of contrast-enhanced ultrasound for differentiation of renal cell carcinoma subtypes and angiomyolipoma

Purpose: To investigate the value of quantitative parameters of contrast-enhanced ultrasound (CEUS) in the differentiation of subtypes of renal cell carcinoma (RCC) and angiomyolipoma (AML). Methods: The quantitative characteristics of 341 RCCs and 88 AMLs were analyzed with quantitative software (SonoLiver). Quantitative analysis was conducted in the whole tumor (ROItumor) and the maximum enhanced area of the tumor (ROImax), acquiring the parameters of maximum intensity (IMAX), rise time (RT), time to peak (TTP), mean transit time (mTT), and area under the curve (AUC), were derived and analyzed. The difference values between ROImax and normal renal cortex (Delta Par.s, including Delta IMAX, Delta RT, Delta TTP, Delta mTT, Delta AUC) were compared among renal histotypes. Results: All time-related parameters (including RT, TTP and mTT) of ROImax were shorter than the corresponding parameters of ROItumor in RCC subtypes (all p < 0.05), but made no statistical difference in AMLs (all p > 0.05). There were significant differences of all Delta Par.s among RCC subtypes and AML (all p < 0.01). Delta IMAX and Delta AUC showed the trend that ccRCC >AML > pRCC = chRCC. Delta TTP showed AML = pRCC= chRCC > ccRCC, Delta RT and Delta mTT showed AML > pRCC = chRCC= ccRCC. Delta mTT could distinguish RCC from AML with the area under the ROC curve (AUC) of 0.86. The AUC of Delta IMAX and Delta AUC was 0.89 and 0.92 vs 0.85 and 0.85 for discriminating between pRCC (or chRCC) and AML vs ccRCC and AML. Conclusions: Quantitative analysis of CEUS is a useful modality in AML and RCC subtypes' differentiation, by using Delta mTT, Delta IMAX and Delta AUC. (c) 2016 Elsevier Ireland Ltd. All rights reserved.