Comparative viewing modalities for CT cystography

Background: To define the speed and accuracy of two different reconstructive techniques using computed tomography (CT) cystography for the detection and measurement of urinary bladder masses and determine the overall ease of use. Methods: Ten patients scheduled for cystoscopy for the evaluation of hematuria or bladder masses were studied by means of thin-section CT of the air-distended bladder. Two techniques were employed by two radiologists to blindly interpret the data: conventional two-dimensional data with interactive three-dimensional problem solving (2D3DPS) and surface-shaded display (SSD) three-dimensional images. The results were compared with the data from cystoscopy. Results: Twenty-two (100%) of 22 masses detected on cystoscopy were visualized using the reconstructive techniques. Both modalities were shown to have high accuracy, but only the 2D3DPS had a sensitivity and specificity of 100% for both observers at the patient-level diagnosis. The sensitivities for detecting individual masses for the two observers were 100% and 64% for 2D3DPS and 64% and 70% for SSD. Conclusion: Both methods used to display the CT data had a high sensitivity and specificity for masses, but only the 2D3DPS had a sensitivity and specificity of 100% at the patient-level diagnosis, thus making it a feasible imaging modality for cystography. It was also preferred overall for ease of use, high accuracy, and relative low cost. Received: 22 March 2000/Accepted: 3 May 2000