The Value of Contrast-Enhanced Ultrasound (CEUS) in Detecting Minute Renal Cell Carcinoma

Objectives: To investigate the value of contrast-enhanced ultrasound (CEUS) in the detection of minute renal cell carcinoma (MRCC) compared to conventional ultrasound (US) and contrast-enhanced computed tomography (CECT). Methods: Thirty-eight consecutive patients with 38 histopathologically proven MRCCs (515 mm) were enrolled in our study. CEUS and CECT were available in 38 and 24 patients, respectively. The features of CEUS were evaluated and compared to conventional ultrasound (US) and CECT. Results: Ten (26.3%) tumors could not be detected by conventional US, while all tumors were detected by CEUS. The features of tumor border, blood flow, and echogenicity had significant difference between conventional US and CEUS (p=0.000, p=0.003, and p=0.012, respectively). The score of visibility of tumors by CEUS was significant higher than that of conventional US. The sensitivity, specificity, and accuracy of conventional US and CEUS in evaluating tumor necrosis were 42.9%, 50%, and 47.4% vs. 85.7%, 95.8%, and 92.1%, respectively. The enhancement features of MRCC including tumor vascularization, homogeneity, and border had no significant difference between CEUS and CECT (all p> 0.05). On CEUS, synchronous-in (89.5%), hypervascular (84.2%), and fast-out (71.1%) were the most commonly observed enhancement characteristics for MRCC. Conclusion: CEUS performs better in detecting MRCC than conventional US, and it has the same capabilities in reflecting the enhanced features of MRCC as CECT.