Abstract
During the recanalization of chronic total occlusions in the superficial femoral artery, severe calcification adds technical difficulty in guidewire crossing due to poor ultrasound visualization and uncontrollable guidewire manipulation. Herein, we present the case of a 70-year-old man with chronic total occlusion of the superficial femoral artery to report the "perivascular radiolucent line" indicating aspirated air in the subintimal space, which could be noted after a failed subintimal angioplasty. The perivascular radiolucent line helped a safe guidewire tail crossing by making the vascular wall visible. Physicians should be aware of the perivascular radiolucent line in case of failed subintimal angioplasty.