Usefulness of Virtual Cystoscopy using a 64-channel Multidetector-row Computed Tomography Scanner for Detecting Bladder Tumors

Abstract

Purpose: We evaluated the clinical usefulness of air filled axial computed tomography (CT) images and virtual cystoscopy (VC) with using a 64channel multidetector-row CT (MDCT) scanner for the detection of bladder tumors. Materials and Methods: Fifty-nine patients who displayed gross hematuria or a clinical suspicion of bladder tumor were scanned using a 64-channel MDCT scanner. The unenhanced CT images of the urinary bladder were obtained, with the patients in the supine and prone positions, following drainage of urine and distension of the bladder with approximately 300-500cc of room air through a urethral catheter. The CT data were transferred to a workstation for reconstructing the VC images. Two radiologists independently interpreted the axial and virtual images, and discrepancies were resolved by working in consensus. The results of the VC were compared with the findings of conventional cystoscopy or the operative findings. Results: Abnormal findings were identified by the axial CT images and VC in 54 (91.5%) patients. All bladder lesions demonstrated with the VC were seen on conventional cystoscopy. On the VC, lesions greater or equal to 1.4mm in diameter could be identified. But there were 3 false negative findings in cases of sessile masses smaller than 5mm and cases with a trabeculated bladder. There were no false-positive findings. The sensitivity of the technique was 100% for tumors larger than 0.5cm. Conclusions: VC with using 64-channel MDCT scanner was very accurate at identifying masses larger than 0.5cm and it can show a mass as small as 1.4mm. Bladder tumors can be diagnosed less invasively using air-filled VC. However, in the case with severe bladder trabeculation or wall thickening, we recommend conventional cystoscopy rather than VC. (Korean J Urol 2007;48:383-389)