Utility of routine trauma CT in the detection of bladder rupture

The purpose of this study was to determine the frequency with which routine computed tomography (CT) fails to depict bladder rupture, the potential utility of delayed CT scans, and whether these findings might be useful in determining which patients may require subsequent cystography.

Cystograms and abdominal and pelvic CT scans of 54 patients with blunt trauma and in whom bladder rupture was clinically suspected were retrospectively reviewed. Blind readings of CT scans were performed by two genitourinary radiologists. Cystograms were used as the standard.

Cystograms depicted bladder rupture in 10 patients. On CT scans, extravesical fluid was depicted in all three patients with intraperitoneal bladder rupture (although only a small amount of pelvic intraperitoneal fluid was present in two of these patients), in all seven patients with extraperitoneal bladder rupture, and in 32 of the 44 patients without bladder injury. Contrast material had been excreted into the bladder at the time of the initial or delayed CT in eight patients with bladder rupture; however, extravasation was identified in only four of the eight. In two of the four patients without extravasation, the bladder was distended at the time of CT. No bladder injuries were found in the 12 patients in whom pelvic fluid was not identified on CT scans.

The absence of pelvic fluid on a trauma CT scan indicates that bladder rupture is unlikely. Even when a partially opacified bladder is passively distended, bladder injury may be present despite the absence of contrast material extravasation.