Abstract: Objective To study the importance of contrast-enhanced ultrasound(CEU) in the differential diagnosis of local renal space occupying lesons. Methods Seventy-six cases of renal space occupying lesions were examined by contrast-enhanced ultrasound. All patients received surgery. The characteristics of renal space occupying lesions in CEU were observed and analyzed. Results Satisfactory and dynamic-enhanced perfusion images were obtained for 76 patients. Among them, 62 lesions were diagnosed as malignant and 14 lesions as benign tumor by pathology. The way of contrast medium wash in and wash out was various. Most cases showed synchronous wash in and fast wash in(P<0.05). There was no difference between fast wash out and low wash out. A special characteristic of the malignant renal lesions was that they were rich in blood supply, tending to look like a "bright ball". Hamartoma showed asymmetric enhancement without pseudocapsule. There was no enhancement found in cases of cysts. Conclusion The contrast-enhanced ultrasound(CEU) is a useful method for differentiating renal space occupying lesions.

Key words: renal tumor, renal space occupying lesion, contrast-enhanced ultrasound