The value of CT in the detection of bladder and posterior urethral injuries.

To determine the value of CT in the diagnosis of bladder and posterior urethral injuries, we retrospectively evaluated the CT and urethrocystographic findings in 33 trauma patients with suspected injuries of the lower urinary tract who had both studies in their initial evaluation. In 26 (79%) of 33 patients, results of both examinations were normal. Seven (21%) of 33 patients had bladder injuries (seven--two in one patient) and/or posterior urethral injuries (three) as determined on the basis of urethrocystography. Three patients had extraperitoneal bladder tears as the only injury to the lower urinary tract. Two patients had both extraperitoneal bladder tears and posterior urethral injuries. One patient had both an extraperitoneal tear at the bladder base and an intraperitoneal rupture at the bladder dome. The seventh patient had an isolated posterior urethral injury. All seven bladder injuries were detected with CT. In these cases, CT findings included (1) free intraperitoneal contrast material (one case), (2) focal contrast extravasation (three cases), and (3) paravesical fluid collections that on delayed CT scans revealed contrast accumulation in the fluid, indicating extravasation (two cases). The seventh bladder injury was suspected on CT and confirmed with retrograde urethrography. Only one of three posterior urethral injuries was detected with CT. Our results suggest that CT is sensitive in the detection of bladder injuries, but not for the diagnosis of urethral injuries.