Contrast-Enhanced Ultrasound Characteristics of Renal Pelvis Urothelial Carcinoma and Its Relationship with Microvessel Density

We studied the characteristics of contrast-enhanced ultrasound (CEUS) in renal pelvic urothelial carcinomas and explored its performance in assessing microvessel density (MVD) of tumor tissues. We retrospectively analyzed the characteristics of 125 cases, which were confirmed pathologically to be renal pelvic urothelial carcinomas using CEUS. We performed CEUS and found that most tumors presented with an enhanced mode of "slow-in (mean = 16.7 ± 2.6 s, range: 12–25 s), hypo-enhancement and fast-out (mean = 69.3 ± 16.2 s, range: 42–113 s)." However, the wash-in pattern, homogeneity and wash-out pattern observed with CEUS was not correlated with pT stage and grade (p > 0.05). But advanced-pT-stage and high-grade tumors had a higher peak enhancement than early-pT-stage and low-grade tumors (p < 0.01). Peak enhancement obtained with CEUS can be used to evaluate the pT stage and grade of renal pelvic urothelial carcinomas more effectively. The MVD of those tissues was observed using immunohistochemical staining of cluster of differentiation 34 (CD34). MVD in the advanced-pT-stage and high-grade groups was significantly higher than that in the early-pT-stage and low-grade groups (p < 0.01). As tumor pT stage and grade improved, CEUS peak enhancement intensity and MVD of tumors also exhibited an upward trend. CEUS peak enhancement intensity has the potential to determine MVD of renal pelvic urothelial carcinomas.