Abstract: Objective To evaluate the values of contrast-enhanced ultrasound in diagnosis of cystic renal cell carcinoma. Methods A total of 73 patients with renal cystic lesions were included in this study. The image features of ultrasound and contrast-enhanced ultrasound examination were analysed. All of patients underwent surgical treatment and had pathological results. The diagnostic values of the ultrasound and contrast-enhanced ultrasound were analyzed by evaluating the image features of cystic renal cell carcinoma. Results There were 64 cases of cystic renal cell carcinoma, 9 cases of benign cyst. With ultrasound and color doppler ultrasound， irregular shape, thickness wall, solid ingredients, divisions and more blood flow signals were found in cystic renal cell carcinoma. Renal cyst showed regular shape, few solid component and thin separation and inconspicuous blood flow signals. In contrast-enhanced ultrasound, cystic renal cancer contrast agent appearing time was (15.13±4.21)s, and reached the peak time (23.42±5.68)s, fade time was (28.42±4.27)s. The enhanced mode for fast in and fast out was found in 22 cases (34.3%), fast in and slow out in 30 cases (46.8%), slow in and fast out in 2 cases (3.2%), slow in and slow out in 4 cases (6.4%), and synchronously in and out in 6 cases (9.3%). The hyper-enhancement was found in 42 cases (65.6%), the iso-enhancement and hypo-enhancement in 22 cases (34.4%). In renal cyst, There were three cases out of contrast filling. In other 6 cases, the contrast agent appearing time was (16.67±2.73)s, the peak time was (25.83±3.06)s and fade time was (34.17±4.26)s. The enhanced mode for fast in and fast out was found in 1 case (16.7%), fast in and slow out in 1 case (16.7%) and synchronously in and out in 4 cases (66.6%). The hyper-enhancement was found in 2 cases (33.3%), the iso-enhancement and hypo-enhancement in 4 cases (66.7%). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasound were 85.9%, 66.7%, 94.8%, 40.0% and 83.6%. The sensitiv⁃ ity, specificity, positive predictive value, negative predictive value and accuracy of contrast- enhanced ultrasound were 92.2%, 77.8%, 96.7%, 58.3% and 90.4%. Conclusion Contrast-enhanced ultrasound can be used in benign and malignancy identification of renal cystic lesion.

Key words: kidney neoplasms, ultrasonography, doppler, cystic renal cell carcinoma, contrast-enhanced ultrasonography techniques, sensitivity and specificitytechniques