Carlos Nicolau MD, Presenter: Nothing to Disclose

Laura Bunesch Villalba MD, Abstract Co-Author: Nothing to Disclose

Blanca Pano Brufau MD, Abstract Co-Author: Nothing to Disclose

Rafael Salvador Izquierdo MD, Abstract Co-Author: Nothing to Disclose

Carmen Sebastia Cerqueda MD, Abstract Co-Author: Nothing to Disclose

Laura Oleaga, Abstract Co-Author: Nothing to Disclose

The aim of this study was to assess the accuracy of contrast-enhanced ultrasound (CEUS) in the characterization of renal nodules indeterminate on CT by identifying benign cystic lesions not requiring histological diagnosis.

72 patients with 83 indeterminate renal nodules on CT underwent baseline US and CEUS that classify lesions as benign (Bosniak I, II or IIF cysts) or potentially malignant (Bosniak III or IV cysts, solid nodules). The reasons to consider a nodule as indeterminate include: A. Study with only an unenhanced phase with a nodule > 20HU; 10 nodules. B. Study without an unenhanced phase; 40 nodules; C. Study with an unenhanced and at least 1 enhanced phase with a nodule > 20HU and a difference of enhancement <20HU between the unenhanced and enhanced phases; 33 nodules. The accuracy of US and CEUS in the differentiation between benign cysts and potentially malignant nodules was analyzed and compared with the final diagnosis obtained by histology or follow-up of at least 18 months with CEUS +/- a conclusive CT /MR study.

Final diagnoses comprised 50 benign complex cysts (44 Bosniak I-II and 6 Bosniak IIF), 1 focal nephritis, 1 multilocular cystic nephroma, 3 oncocytomas, 1 transitional cell carcinoma and 27 renal cell carcinomas. CEUS correctly classified 48 out of 50 (96%) nodules as benign complex cysts with a final diagnosis of Bosniak I-II or IIF cysts and 31 out of 33 (93.9%) nodules as potentially malignant with a final diagnosis of Bosniak III, IV or solid lesions, with a sensitivity of 96%, specificity of 93.9%, positive predictive value of 96%, negative predictive value of 93.9% and accuracy of 95.2%. The accuracy of CEUS was significantly better than that of US (95.2% vs. 45%).

CEUS is very useful in the differentiation between benign complex cysts and other lesions that require further investigation in non-conclusive renal nodules detected on CT.

The use of CEUS to differentiate benign cystic lesions that do not require immediate further investigation (Bosniak I-II-IIF cysts) from other potentially malignant solid lesions and complex Bosniak III or IV cysts that usually require histology to achieve a final diagnosis facilitates the management of indeterminate renal masses with the advantage of its price and absence of radiation and nephrotoxicity.

Nicolau, C, Bunesch Villalba, L, Pano Brufau, B, Salvador Izquierdo, R, Sebastia Cerqueda, C, Oleaga, L, Usefulness of Contrast-enhanced Ultrasound in the Characterization of Renal Nodules Indeterminate on Computed Tomography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14000127.html