Michele Bertolotto MD, Presenter: Nothing to Disclose

Ferruccio Degrassi MD, Abstract Co-Author: Nothing to Disclose

Marco Cavallaro MD, Abstract Co-Author: Nothing to Disclose

Paola Martingano, Abstract Co-Author: Nothing to Disclose

Micheline Djouguela Fute MD, Abstract Co-Author: Nothing to Disclose

Maria Assunta Cova MD, Abstract Co-Author: Nothing to Disclose

To assess the diagnostic performance of contrast enhanced ultrasound (CEUS) in evaluation of atypical cystic renal masses using the Bosniak classification system in a series of 117 consecutive patients. Helical CT was used as reference procedure.

109 consecutive patients with 117 cystic renal masses atypical at US underwent CT and CEUS. Thirty-five lesions were resected, the remaining atypical cysts were followed up for 2-5 years. Images and digital cine clips were retrospectively evaluated by blind readers. Basing on CT appearance a Bosniak score was assigned. Similar criteria modified for US imaging were used to score atypical cysts at CEUS. For each lesion, number of septa, thickness of wall and septa, presence of calcifications, and contrast enhancement characteristics were evaluated with both techniques.

At CT lesions were scored as category I (n=3), II (n=49), IIF (n=29), III (n =21), and IV (n =15). All type IV and 18/21 type III lesions were surgically removed. All category IV and 11/18 category III lesions of the surgical group were malignant. In 102/117 (87%) lesions CT and CEUS scores were equivalent, while in 15 lesions (13%), there were differences. Among 9 category I-II at CT, 6 were scored 2F, and 1 was scored III at CEUS. One malignant lesion was scored III at CT, and 2 at CEUS. Two malignant lesions were scored 2F at CT and III-IV at CEUS. The presence of vascularised wall nodules was better depicted at CEUS in 2 malignant cysts, which upgraded from category 2F at CT to category III and IV at CEUS, and was better depicted at CT in 1 malignant cyst, which downgraded from category III at CT to category IIF at CEUS.

CEUS shows similar findings as CT in 87% of complex cystic renal lesions. However, differences exist that can be useful to differentiate benign from malignant lesions in ambiguous cases.

Complex cysts are characterized effectively with CEUS which could be considered complementary to CT in selected cases, and alternative to CT in the follow up or in patients with renal insufficiency.

Bertolotto, M, Degrassi, F, Cavallaro, M, Martingano, P, Djouguela Fute, M, Cova, M, CEUS of Cystic Renal Masses Atypical at US: Comparison with CT in a Consecutive Series of 117 Lesions.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012336.html