Diagnostic Value of Conventional Ultrasound Combined With Contrast-Enhanced Ultrasound for Differentiating Small Clear Cell and Non-Clear Cell Renal Cell Carcinomas.

Abstract

Background: Renal cell carcinoma (RCC) is the most common malignant tumor of the kidney and accounts for the majority of renal malignancies. The detection of small RCCs has increased in recent years, largely owing to advances in imaging techniques. To date, few studies have investigated the diagnostic value of contrast-enhanced ultrasound (CEUS) in differentiating clear cell renal cell carcinomas (ccRCCs) from non-clear cell renal cell carcinomas (non-ccRCCs) when smaller than 4cm. In this study, we aimed to retrospectively explore the value of conventional ultrasound combined with CEUS in differentiating the two main RCC subtypes.

Methods: Altogether, 84 RCC cases were included, comprising 62 ccRCCs and 22 non-ccRCCs. All patients underwent conventional ultrasound and CEUS before surgery. To determine the independent predictors of small ccRCC, we conducted univariate and multivariate logistic regression analyses on the clinical data and ultrasound imaging features of the patients. Receiver operating characteristic (ROC) curve analysis was performed to assess diagnostic performance.

Results: Multivariate logistic regression identified cystic change (odds ratio (OR) = 5.959; p = 0.017), parenchymal phase isoenhancement (reference: hypo-enhancement; OR = 6.411; p = 0.007), and hyperenhancement (reference: hypo-enhancement; OR = 15.770; p < 0.001) as independent predictors for distinguishing between small ccRCC and non-ccRCC. Routine ultrasound combined with CEUS demonstrated good evaluation efficacy, with an area under the curve (AUC) of 0.823 (95% confidence interval: 0.733-0.914).

Conclusions: This study provides preliminary evidence supporting the use of conventional ultrasound with CEUS for differentiating ccRCCs from non-ccRCCs <4 cm. These findings require confirmation by independent large-scale studies.