Angiogram Enigma (IMAGE) University of Southern California Caption The lower artery in the illustration has a plaque deposit. But is it unstable, requiring immediate surgery, or stable, in which case medication and exercise might be used instead. Current angiogram imaging can't distinguish the two types. Credit USC Viterbi School of Engineering Usage Restrictions Credit USC School of Engineering License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.