Usefulness of contrast enhanced ultrasound for evaluation of cystic renal masses

OBJECTIVE: Contrast enhanced ultrasound (CE) consists of the intravenous injection of gas microbubbles and their detection within the kidney in different phases. CE is more accurate than contrast enhanced tomography for detection of septa and wall thickness vascularization in cystic renal lesions. The purposes of this study are to confirm the usefulness of this tool in the characterization of complex cystic renal masses and to assess its histological correlation. MATERIALS AND METHODS: Retrospective observational study of 78 patients with complex or indeterminate cystic renal masses who underwent a CE between January 2015 - January 2020. RESULTS: Lesions with high suspicion of malignancy (Bosniak III and IV) were identified in 35 patients (45%). A surgical approach was taken in 23 (30%): 18 patients with histology of renal cell carcinoma, and only in 4 the histology was benign. CE involved a change in therapeutic management due to better definition of the lesion in 48 patients (61.5%). CE has a sensitivity 100%, specificity 91.5%, PPV 81.8%, NPV 100%, and CE had an important confidence level showed by the area under the ROC curve (AUC = 0.968). CONCLUSIONS: CE is a useful tool in the characterization of complex cystic renal lesions. It allows a better definition of the Bosniak classification for those indeterminate or doubtful cases on CT that could generate a change in the therapeutic attitude in many cases. It has a good image - histology relation.