[Role of contrast enhanced US in the evaluation of renal tumors].

PURPOSE: To evaluate the role of contrast enhanced US in the characterization of renal tumors. Materials and methods. Eighty-six renal tumors (33 solid, 53 cystic) underwent contrast enhanced US after indeterminate CT/MRI (67 lesions) or US (19 lesions). Pathological correlation was available for 42 cases, and follow-up at 3 and 6 months was available for 13 cases. Diagnosis was achieved in 21 cases. Lesions included: 19 renal cell carcinomas (4 conventional, 14 papillary, 1 tubulocystic), 5 oncocytomas, 3 metastases, 6 pseudomasses, and 53 cystic lesions including 6 malignant tumors.
RESULTS: Solid tumors were correctly identified in 100% of cases. Characterization of solid tumors was possible with specificity of 92.9% for papillary carcinoma, 57.1% for clear cell carcinoma, and 100% for oncocytoma. The specificity for distinguishing solid benign from solid malignant tumor was 100% based on the presence of hypoechogenicity relative to normal renal parenchyma on delayed imaging. Contrast enhanced US allowed reclassification of 23 indeterminate lesions on conventional US. It is of limited value for large cystic lesions or cystic lesions with extensive wall calcification.
CONCLUSION: Contrast enhanced US is easily performed in clinical practice and allows improved characterization of some renal tumors compared to other cross sectional imaging techniques.