Purpose: We evaluated the usefulness of dynamic enhanced magnetic resonance imaging (MRI) in the staging of superficial tumors following a bolus administration of gadopentetate dimeglumine.
Materials and methods: In 48 patients with proved bladder tummors the results of preoperative plain spin echo T1 (repetition time/echo time 500/20 msec.) and T2 (repetition time/echo time 2,000/40 to 100 msec.)-weighted MRI, dynamic gadolinium-enhanced MRI (repetition time/echo time 200/15 msec.) and late gadolinium-enhanced MRI (repetition time/echo time 500/20 msec.) were compared and correlated with the histopathological findings.
Results: Unenhanced spin echo T1 and T2-weighted MRI sequences were able to stage correctly 14 (56%) and 17 (68%) of 25 superficial bladder cancers, respectively. Muscular infiltration (stages pT2 and pT3a) was correctly depicted in 3 (27%) and 6 (54%) of 11 cases respectively, with over staging being the most frequent error. On the basis of the dynamic gadolinium-enhanced T1-weighted MRI appearance, superficial involvement of the bladder wall was correctly assessed in 21 of 25 cases (84%) and muscular infiltration (stages pT2 to pT3a) in 7 of 11 (63%). Delayed enhanced T1-weighted sequences showed a low accuracy rate in staging superficial tumors (44%). The overall accuracy of T1 and T2-weighted, dynamic T1-weighted and delayed T1-weighted MRI in staging bladder cancer was 58, 71, 81 and 56% respectively.
Conclusions: The use of gadolinium improved the accuracy of dynamic enhanced MRI in staging superficial bladder cancer. On the contrary, delayed enhanced MRI was not useful for staging superficial bladder cancer. The degree of bladder distension was a determinant factor in staging superficial tumors.