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.