CT virtual endoscopy of intravenous cystography

Objective: To investigate the technique of CT virtual endoscopy of intravenous cystography. Methods: Ninety-four patients were enrolled in the study. One group of 30 patients emptied the bladder completely after contrast-enhanced CT of the pelvis and then drank 300 ml of water to re-fill the bladder. Patients rolled over twice on the examining table before the CT virtual cystoscopy. The second group of 32 patients underwent the same procedure and the amount of water ingested was determined by the pre-void bladder volume. The third group of 32 patients underwent CT virtual cystoscopy 30 minutes after contrast-enhanced pelvic CT without emptying the bladder or drinking water. CT values were measured in different regions of the bladder lumen and the CT virtual cystoscopic images were scored. The results were compared among the 3 groups of patients. Results: The intravesical CT values of the first 2 groups of patients ingesting water after voiding were significantly different from that of the group without voiding or ingesting water (P < 0.001). The density of urine in the first 2 groups was more homogeneous than that of the third group. The image quality was significantly better in the first 2 groups than that of the 3rd group with higher the scores (P < 0.001). Conclusion: Good image quality can be obtained by complete bladder emptying after contrast-enhanced pelvic CT and ingesting 30 ml of water before CT virtual cystoscopy. (authors)