Helical CT virtual endoscopy of urinary tract:clinical applications and limitations

Objective To evaluate the clinical applications and limitations of helical CT virtual endoscopy (CTVE) in urinary tract diseases. Methods CTVE was performed in 53 patients suspected urinary tract diseases, all cases were confirmed by conventional cystoscopy and/ or surgery. CTVE images were generated from the volumetric data of the excretory phase using helical CT. The results were then compared with the findings of axial, MPR and 3D images and conventional cystoscopy in a double blinded manner. Results CTVE could clearly display the normal anatomic structures of the urinary tract. The location, size, numbers, configuration and extension of lesions showed on CTVE were corresponded well with that of conventional cystoscopy. The sensitivity to vesical carcinoma was 94.7%,2 tumors smaller than 5mm depicted on CTVE images were not seen on the axial images. Whereas areas of wall thickening and extravesical invasions were more readily appreciated on axial and MPR images. CTVE image was not as good as the axial, MPR and 3D images in demonstrating the lesion of the pelvis and ureter. Conclusion CTVE has proved to be a noninvasive and reliable technique in the detection and diagnosis of bladder lesions, but it was less useful in evaluating the diseases of the pelvis and ureter. The optimal evaluation of urinary tract diseases of CTVE should combine with the interpretation of axial and MPR images.