Diagnostic potential of virtual cystoscopy of the bladder: MRI vs CT. Preliminary report.

The aim of the study was to evaluate the diagnostic potential of the half-Fourier acquired single-shot turbo spin echo (HASTE) sequence for MRI cystoscopy compared with CT cystoscopy and the gold standard conventional cystoscopy. The MRI- and CT cystoscopy was performed in 29 patients with bladder tumors documented at cystoscopy and a control group using a 1.5-T unit (6-mm slice thickness) and a helical CT (3-mm collimation, pitch 1) after filling the bladder with air. Axial MRI and CT images were transferred to a workstation for application of virtual cystoscopy and compared with routine cystoscopy. Axial images and virtual cystoscopies were read by three readers for size and location of tumors. Forty-seven tumors were diagnosed at cystoscopy (12<1 cm, 35>/=1 cm). The sensitivity for detection of tumors smaller than 1 cm was 88.9% at MRI cystoscopy and 100% for tumors of 1 cm or larger. These results were not statistically different from the other modalities. Three tumors smaller than 1 cm were not detected at CT cystoscopy, four not all identical at MRI cystoscopy. One tumor with a wall thickening was detected on axial CT and MR images and CT cystoscopy by all observers, but only by two at MRI cystoscopy. The MRI cystoscopy is a diagnostic modality with results comparable to conventional and CT cystoscopy.