Contrast-enhanced ultrasonography with a new contrast agent (SonoVue) for characterization of renal tumors

Due to the increased use of imaging techniques such as ultrasound and computed tomography, an increasing number of renal tumors are being diagnosed incidentally. These tumors are often smaller and in an earlier stage, and it is difficult to distinguish benign from malignant tumors. The purpose of this study was to evaluate the value of Contrast-Enhanced Ultrasonography (CEUS) in the characterization of renal tumors. Fifty-six patients with renal tumors underwent CEUS examination using the contrast agent SonoVue® with the cadence Contrast Pulse Sequencing (CPS) technique. The duration of tumor and renal parenchyma enhancement after injection of the contrast agent were recorded, and the enhancement patterns during the cortical, parenchymal, and late phases were evaluated. The enhanced features of renal cell carcinoma and renal angiomyolipoma were displayed. Renal cell carcinoma showed hype- or iso-enhancement in the cortical phase and hypo-enhancement in the parenchymal and late phases. Renal angiomyolipoma showed hypo-enhancement during the entire contrast process. A thin, perilesional, rim-like hyper-enhancement in the late phase was the characteristic feature of renal cell carcinoma in CEUS. The diagnostic efficacy of CEUS in the characterization of renal tumors was as follows: sensitivity 91% (42/46), specificity 70% (7/10), positive predictive value 93% (42/45), negative predictive value 64% (7/11), and diagnostic accuracy 86% (49/56). Our results indicated that CEUS with SonoVue® might evaluate the vascularity of renal tumors in real time and provide useful information for their differential diagnosis and further treatment.