Materials and Methods: A total of 70 patients diagnosed with bladder cancer between February 2022 and February 2023 were prospectively included in the study. Preoperative CT urography was performed in all patients. Hounsfield unit (HU) measurements were obtained from the tumor in both non-contrast and nephrographic phases. The difference between these values was defined as the contrast enhancement level. The association between contrast enhancement and tumor grade, recurrence, and muscle invasion was statistically analyzed.
Results: High-grade bladder tumors were identified in 46 patients, while 24 had low-grade tumors. The contrast enhancement values were significantly higher in high-grade tumors compared to low-grade tumors (28.9 ± 11.8 HU vs. 17 ± 10.3 HU, p <0.01). Among the 16 patients who experienced tumor recurrence, the enhancement values were significantly higher than those without recurrence (30.3 ± 10.5 HU vs. 23.2 ± 12.8 HU, p <0.05). In cases of muscle-invasive tumors, contrast enhancement levels were significantly higher than those in non-muscle-invasive tumors (41.75 ± 4.8 HU vs. 22.6 ± 11.6 HU, p <0.01). ROC analysis revealed a threshold value of 19.5 HU for distinguishing high- and low-grade tumors (sensitivity: 80%, specificity: 75%), and 36 HU for detecting muscle invasion (sensitivity: 100%, specificity: 84%). According to the multivariate logistic regression analysis, contrast enhancement was identified as an independent risk factor for high-grade bladder tumors (OR = 1.09, 95% CI: 1.031–1.152, p = 0.02).
Conclusion: The amount of contrast enhancement observed in preoperative CT urography of bladder tumors may serve as a useful imaging biomarker for assessing tumor aggressiveness and preoperative risk stratification.. Further studies with larger patient cohorts are needed to validate these findings.