Intravascular ultrasound (IVUS) is the "state-of-the-art" technique for imaging and analyzing coronary plaque extent and composition. Despite small-sized IVUS catheters complications are possible during the procedure such as acute coronary dissection, perforation, and vessel thrombosis. The authors report the case of an acute dissection of the right coronary artery during analysis of an ambiguous plaque lesion. At the same time, IVUS is also helpful to reposition the guide wire from the false to the true lumen and to seal the dissection membrane by stent placement.