Radiology: Volume 249: Number 1—October 2008
Cheryl A. Sadow, MD Stuart G. Silverman, MD Michael P. O'Leary, MD James E. Signorovitch, PhD
Purpose: To evaluate the performance characteristics of computed tomographic (CT) urography for the detection of bladder cancer in patients at risk for the disease.
Materials and Methods: Institutional review board approval was obtained for this retrospective HIPAA-compliant review of medical records of 2600 consecutive patients undergoing CT urography. Of these, 838 CT urograms in 779 patients (449 men, mean age of 62 years, range of 27-92 years; 330 women, mean age of 56 years, range of 18-86 years) evaluated for hematuria or a history of urothelial cancer, who had undergone cystoscopy within 6 months of the CT urogram, were included in the study. Clinical reports of CT urograms containing a bladder lesion interpreted as suspicious for malignancy were classified as positive. All others were classified as negative. Cystoscopy reports were classified as positive if a lesion underwent biopsy or was resected or negative if no lesion was detected. Performance characteristics for both CT urography and cystoscopy were determined by using pathologic findings or clinical follow-up as the reference standard. Ninety-five percent confidence intervals were estimated for each test characteristic.
Results: The overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value (NPV) for bladder cancer detection were 79% (117 of 149), 94% (649 of 689), 91% (766 of 838), 75% (117 of 157), and 95% (649 of 681) for CT urography and 95% (142 of 149), 92% (634 of 689), 93% (776 of 838), 72% (142 of 197), and 99% (634 of 641) for cystoscopy. The NPV of CT urography was higher in patients evaluated for hematuria alone (98%, 589 of 603). However, the accuracy of CT urography was considerably lower in patients with a prior urothelial malignancy (78%, 123 of 158).
Conclusion: CT urography is an accurate noninvasive test for detecting bladder cancer in patients at risk for the disease. The high NPV of CT urography in patients with hematuria may obviate cystoscopy in selected patients.