Usefulness of Dynamic Gadolinium-enhanced MR Imaging in Staging of Bladder Cancer

ABSTRACT

PURPOSE: To evaluate the usefulness of dynamic gadolinium-enhanced MR imaging in the staging of bladder cancer. MATERIALS AND METHODS: Twenty-four patients with histologically proven bladder cancer underwent MR imaging before tumor resection. Pre contrast axial or sagittal T1- and T2-weighted images were obtained in all patients. In 12, dynamic MR imaging was performed using the 3D-EFGRE technique in the axial plane. Images were obtained 30, 90, and 180 sec after a rapid hand injection of Gd-DTPA. T1W1, T2W1, and Gd-enhanced dynamic images were compared on the basis of lesion conspicuity and correlated with histologic specimens. The signal intensity ratio (SIR) of bladder tumors, muscle, and perivesical fat during each phase, and the contrast-to-noise ratio (CNR) of lesion-to-muscle and lesion-to-fat were determined. RESULTS: The accuracy of tumor staging using both T1WI and T2WI was 38% (9/24), and the accuracy of dynamic gadolinium enhanced MR imaging was 58% (7/12). The difference was statistically significant (p<0.05). The SIR of tumors was highest during the capillary phase, and decreased during the venous phase. During all phases i t was significantl y higher than that of bladder muscle and perivesi cal fat ( P < 0.05). The CNR of tumor-to-muscle and tumor-to-perivesical fat increased abruptly during the arterial phase, was highest during the capillary phase and decreased slightly during the venous phase. CONCLUSION: Dynamic gadolinium enhanced MR imaging improves the diagnostic accuracy of both T1WI and T2WI in the preoperative staging of bladder cancer and can be useful in the management and estimation of prognosis. For evalvation of the staging of bladder cancer, the capillary phase is optimal.