Carbon Dioxide Angiography for the Detection of Lower Gastrointestinal Arterial Bleeding Initially Occult to Angiography with Iodinated Contrast Media.

This study evaluated the utility of carbon dioxide (CO) in angiography for the detection of lower gastrointestinal arterial bleeding initially occult to angiography with iodinated contrast media. Fourteen patients underwent CO-enhanced angiography. In all patients, extravasation was identified by contrast-enhanced computed tomography but not by initial iodinated contrast-enhanced angiography. After iodinated contrast-enhanced angiography, CO-enhanced angiography was performed from the same catheter position. The detection capability for extravasation on CO-enhanced angiography was evaluated. CO-enhanced angiography allowed for the visualization of extravasation and subsequent transcatheter arterial embolization in 11 of 14 (79%) cases, with extravasation seen during either CO-enhanced angiography (n = 8) or subsequent repeat iodinated contrast-enhanced angiography immediately after negative CO-enhanced angiography (n = 3). Conservative treatment was performed in the remaining 3 cases. In conclusion, CO-enhanced angiography appears useful for identifying occult lower gastrointestinal bleeding.