Role of contrast-enhanced ultrasound in the differentiation of high- and low-grade urothelial carcinoma.

ABSTRACT

OBJECTIVE: To investigate the role of contrast-enhanced ultrasound in the differential diagnosis of high- and low-grade urothelial carcinoma. METHODS: The radiological data of 96 patients with urothelial carcinomas who had undergone gray-scale contrast-enhanced ultrasound from August 2010 to April 2011 were analyzed retrospectively. Pathological examination demonstrated that the tumors were high-grade in 55 cases (high-grade group) and low-grade in 41 cases (low-grade group). The dynamic images were analyzed by time-intensity curve, and the arrival time (AT), peak intensity (PI), time to peak (TTP), and washout time (WT) were measured. The enhancement patterns of different urothelial carcinomas were analyzed. RESULTS: Both PI (P=0.005) and WT (P=0.002) were significantly higher in high-grade group than in low-grade group, whereas AT (P=0.374) and TTP (P=0.386) showed no significant difference between these two groups. In the high-grade group, 47 cases (85.5%) were identified as fast wash-in and slow wash-out; in the low-grade group, 35 (85.4%) were identified as fast wash-in and fast wash-out. When the enhancement pattern was used as a diagnostic indicator for differentiating urothelial carcinomas, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 85.5%, 90.2%, 87.5%, 92.2%, and 82.2% for high-grade tumor and 85.4%, 90.9%, 88.5%, 87.5%, and 89.3% for low-grade tumor. CONCLUSIONS: Different grade urothelial carcinomas show different enhancement finding on contrast-enhanced ultrasound. The enhancement pattern can serve as an important diagnostic indicator.