[en] Magnetic resonance imaging (MRI) and CT were performed for 18 patients with urinary bladder tumors (1 urachal tumor), and their findings were compared with pathologic staging. Dynamic MRI enhanced by Gd-DTPA (diethlamine triaminepentaacetic acid) was performed for 6 out of the 18 patients. All the 18 tumors were detectable with MRI and CT, and the detectability rate was 100%. All the locations of the bladder tumors were compatible with the cystoscopic findings. The staging accuracy of MRI was 12 out of 18 patients (75%), while there was overstaging for 4 patients and understaging for 2 patients. Accuracy of differentiation of less than pT2 and more than pT3a was 15 out of 18 patients (83%). Similarly, the staging accuracy of CT was 10 out of 18 patients (56%), while there was overstaging for 4 patients and understaging for 4 patients. Accuracy of differentiation of less than pT2 and more than pT3a was 14 out of 18 patients (83%). MRI enhanced by Gd-DTPA was performed for 6 out of the 18 patients, but T1-weighted imaging, dynamic MRI (early phase) and dynamic MRI (delayed phase) were found to be superior to T2-weighted imaging concerning the detectability of the tumors. Moreover, dynamic MRI (early phase)was slightly superior to T2-weighted imaging concerning staging accuracy. (author)