Transitional cell carcinoma of the upper urinary tract: staging by MRI.

Background: This study evaluates the ability of MRI to stage transitional cell carcinoma of the upper urinary tract.

Methods: Nine patients who had transitional cell carcinoma of the upper urinary tract detected by other imaging modalities underwent MRI examination at 1.5 T. Imaging included pre- and postgadolinium-DTPA T1-weighted images (9 patients) pre- and postgadolinium chelate T1-weighted fat-suppressed spin echo (7 patients). Postcontrast images were acquired prior to the presence of gadolinium within the collecting system (< 2 min postcontrast), intermediate (2.5-8 min), and late (> 10 min) postcontrast. Images were prospectively interpreted and lesion staging was determined. Correlation with histopathology was obtained in all cases.

Results: Transitional cell cancers were demonstrated in 9/9 patients, and tumors ranged in size from 2 to 8 cm (mean = 3.8 cm) in one dimension. Correct tumor staging was performed in 8/9 patients. The staging error in one case occurred because direct tumor extension into the renal parenchyma was not detected.

Conclusions: The results of this preliminary study show that MRI stages transitional cell cancers relatively well; however, MRI is not able to detect superficial invasion of renal parenchyma.