Carbon dioxide angiography for detecting bleeding in spontaneous retroperitoneal hemorrhage: A case report.

Spontaneous retroperitoneal hemorrhage (SRH) is a potentially life-threatening condition that may require transcatheter arterial embolization (TAE). However, iodinated contrast media (ICM) angiography sometimes fails to detect active bleeding, complicating the identification of the bleeding source and increasing the risk of clinical failure. A 68-year-old man presented with progressive anemia. Contrast-enhanced computed tomography revealed active bleeding in the left iliacus muscle, but initial ICM angiography failed to identify the hemorrhage site. Carbon dioxide angiography was then performed via the left iliolumbar artery, which successfully induced and localized the bleeding, enabling precise embolization without empirical embolization of other vessels. The patient recovered uneventfully with no rebleeding or adverse events. This case suggests that carbon dioxide angiography may aid in inducing and localizing bleeding, improving the success rate of TAE for SRH when ICM angiography fails to detect active bleeding.