Detection of active intraabdominal arterial hemorrhage: value of dynamic contrast-enhanced CT. Contrast-enhanced dynamic CT was used prospectively to diagnose and locate the site of active arterial intraabdominal hemorrhage in 18 patients. Active arterial extravasation was confirmed by angiography in five patients and by immediate surgery in nine. Two patients not undergoing surgery or angiography required multiple blood transfusions to correct rapidly falling hematocrit due to a coagulopathy. One patient died of hypovolemic shock, and autopsy confirmed a large acute retroperitoneal hematoma. Another patient with a splenic laceration and massive hemoperitoneum on CT had no active bleeding at the time of surgery, which was delayed 1 hr from the time of the CT. All patients were clinically thought to be hemodynamically stable and had systolic blood pressures greater than 110 mm Hg at the time of CT. In seven patients, hypotension developed either during (two patients) or immediately after (five patients) CT scanning, necessitating either immediate surgery or angiographic embolization. Contrast-enhanced dynamic CT is valuable in the diagnosis and localization of active arterial intraabdominal hemorrhage. Identification of the anatomic site of this potentially life-threatening hemorrhage is critical in determining whether immediate laparotomy or angiographic embolization is the preferred method of treatment. 