CT Signs of Urethral Injury1

Computed tomography (CT) is the accepted frontline imaging modality for blunt abdominopelvic trauma. However, urethral injuries are traditionally diagnosed with retrograde urethrography. The CT appearances of urethral injuries and the signs associated with posterior urethral injuries are not well described in the literature. CT scans of patients with pelvic fractures and urethrographically proved posterior urethral injuries were evaluated. CT scans of patients with similar pelvic fractures who did not have urethral injuries were also evaluated. The CT findings of elevation of the prostatic apex, extravasation of urinary tract contrast material above the urogenital diaphragm (UGD), and extravasation of urinary tract contrast material below the UGD were specific for type I, II, and III urethral injuries, respectively. If extraperitoneal bladder rupture is present along with periurethral extravasation of contrast material, the possibility of type IV and IVA urethral injuries should be considered. In addition, the CT findings of distortion or obscuration of the UGD fat plane, hematoma of the ischiocavernosus muscle, distortion or obscuration of the prostatic contour, distortion or obscuration of the bulbocavernosus muscle, and hematoma of the obturator internus muscle were more common in patients with pelvic fractures and associated urethral injuries than in patients with uncomplicated pelvic fractures. © RSNA, 2003