Contrast-enhanced ultrasonography in the diagnosis of upper urinary tract urothelial cell carcinoma: A preliminary study

Purpose: The main objective was to assess the effectiveness of contrast-enhanced ultrasonography (CEUS) in the diagnosis of upper urinary tract malignancies by comparing with multidetector computed tomographic urography (MDCTU) and magnetic resonance urography (MRU). Secondary objectives were to compare the tumor size measured with CEUS, MDCTU and MRU and to assess the usefulness of CEUS in distinguishing high-grade tumors from low-grade ones. Materials and Methods: In connection with this prospective study carried out from January 2009 to September 2011, 18 patients underwent MDCTU or MRU, grayscale ultrasonography (US), color Doppler ultrasonography and CEUS followed by surgery and histological examination of the specimen. Quantitative analysis was performed using perfusion software. Time intensity curves were extracted and the following parameters were considered: wash-in time, time-to-peak, maximum signal intensity and wash-out time. Results: Grayscale US identified 15/18 lesions; color Doppler showed no flow signal in 8 lesions, low color signal in 9 lesions and an intense color signal in 1 lesion; CEUS identified 17/18 lesions with the undetected lesion being the smallest one (1.2 cm) located in the upper pelvicalyceal system. Semi-quantitative analysis produced different data for high-grade and low-grade urothelial cell carcinoma (UCC). All detected upper urinary tract masses were UCCs. MRU, MDCTU and grayscale US overestimated the tumor size, while CEUS was the most accurate. Conclusion: CEUS is useful for evaluating upper urinary tract masses as this method permits differentiation between high-grade and low-grade tumors as well as distinction of the tumor from the adjacent structures and accurate mass measurements.