Contrast-enhanced ultrasonography for evaluation of cystic renal mass: in comparison to contrast-enhanced CT and conventional ultrasound

To assess the value of contrast-enhanced ultrasonography (CEUS) in evaluating cystic renal lesions compared with conventional ultrasound (US) and contrast-enhanced computed tomography (CECT).

One hundred and three patients with complex cystic renal masses underwent preoperative US and CEUS, among which 70 conducted CECT at our institution. The images were analyzed with the number of septa, septa and wall thickness and the presence of solid component, and final diagnosis was made.

In malignancies, CEUS demonstrated more septa, thicker wall or septa, and more solid components than US and CECT. CEUS permitted categorization of 51.7% (30/58) and 28.6% (10/35) of malignant tumors in higher grade than by US and CECT, respectively. In benign lesions, CEUS detected more septa than CECT and correctly diagnosed benign cysts which appeared as solid lesions in US. CEUS permitted downgrading of 71.1% (32/45) and 17.1% (6/35) of benign lesions compared to US and CECT. The diagnostic performance of CEUS was better than US for benign cystic lesions. The phenomenon that solid-like component by US did not enhance by CEUS was a strong predictor of benign disease, with a positive predictive value (PPV) of 100%. Enhancement of solid, soft tissue by CEUS was highly predictive of malignancy, with a PPV of 100%.

CEUS was superior to US and CECT in visualizing the number of septa septa and wall thickness, and the presence of solid component of cystic renal lesions. CEUS may play a similar role to CECT in the diagnosis of renal cystic lesions, and better than US.