Value of MRI in Local Staging of Bladder Cancer

Purpose: To evaluate the accuracy of magnetic resonance imaging (MRI) in bladder cancer staging as well as differentiating superficial from invasive tumors and organ-confined from non-organ-confined tumors. Materials and Methods: A total number of 108 bladder tumors in 86 patients (86% men and 14% women) were evaluated by 1.5 Tesla MRI machine. The tumor stages that were determined by MRI study were compared with pathology results after resection of the tumor. Results: The most common stage determined by both MRI and pathology was T2a. Considering stages in details, the kappa agreement coefficient between MRI and pathology was 0.8 (P < .0001). Combining groups a and b in each stage, the kappa agreement coefficient between MRI and pathology was 0.87 (P < .0001). Considering stages in details, we had 22 (20.3%) mismatches in staging between MRI and pathology; 10 (45.5%) were underestimation and 12 (54.5%) were overestimation. Combining groups a and b in each stage, we had 14 (13%) mismatch cases; 6 (46.2%) were underestimation and 8 (53.8%) were overestimation. The detection rate of MRI was 0% in stage Ta, 80% in stage T1, 88.1% in stage T2, 81.2% in stage T3, and 100% in stage T4. The sensitivity and specificity of MRI in differentiating superficial from deep tumors were 0.98 and 0.82, respectively. The sensitivity and specificity of MRI in differentiating organ-confined from non-organ-confined tumors were 0.93 and 0.94, respectively. Conclusion: Magnetic resonance imaging is a reliable modality for determining the stage of bladder tumors with high accuracy, and could show the depth of invasion and extension of tumor that is useful for treatment planning.