Objective: The purposes of this study were to propose and evaluate new diagnostic criteria for the differentiation of category T2 or lower from T3 or higher ureteral urothelial carcinomas on contrast-enhanced CT (CECT) images and to investigate the diagnostic applicability of the criteria.
Materials and methods: The study included 30 patients with ureteral urothelial carcinoma who underwent CECT before surgery. For all patients, unenhanced and contrast-enhanced images (nephrographic and excretory phases) were acquired with a 16- or 64-MDCT scanner. The slice thickness of axial images was 5 mm. A grading system was devised that focused on spiculation and mass formation along the ureter on CECT images to differentiate T2 or lower from T3 or higher tumors. Three radiologists not specialized in abdominal radiology participated in an observer performance study to investigate the diagnostic utility of the criteria. Jackknife ROC analysis was used to compare the radiologists' diagnostic performance without and with the proposed diagnostic criteria. In addition, two board-certified radiologists used consensus to determine the CT grade, and the correlation between CT and pathologic findings was assessed.
Results: The mean AUCs for the three radiologists without and with the proposed criteria were 0.54 (SD, 0.09) and 0.73 (SD, 0.08), indicating a statistically significant difference (p<0.01). For the CT-pathologic correlation, the diagnostic sensitivity and specificity of the proposed criteria with respect to pT3 and higher tumors were 87.5% (14/16) and 92.9% (13/14).
Conclusion: The proposed CT grading system was accurate for differentiating T2 or lower from T3 or higher ureteral urothelial carcinoma.
Keywords: CT; T category; TNM staging system; ureter; urothelial carcinoma.