Fig. 2

a, b Control angiography showed a tandem stenotic lesion in the left proximal superficial femoral artery and total occlusion of the left middle to distal aspects of the superficial femoral artery. c A 0.014-in. guidewire was advanced into the subintimal space (red arrow shows the tip of the guidewire). The black arrow shows the intravascular ultrasound (IVUS) transducer, and the white arrow shows the IVUS wire. The transducer was on the left side of the IVUS wire. d The transducer almost overlapped the IVUS wire (white arrow). On the basis of these findings, we confirmed that the IVUS transducer was at the bottom and the IVUS wire was at the top. e IVUS findings of the chronic total occlusion lesion. The white arrow shows the IVUS wire. The detector direction where the transducer and IVUS wire coincided on the angiographic image was left anterior oblique (LAO) 15° (yellow arrow). The detector direction where the transducer and target plaque were maximally separated at right anterior oblique (RAO) 30° (red arrow) was at 45° rotation to a clockwise direction from LAO 15° to RAO 30° (white arc arrow). The center of the target plaque was a few millimeters to the right of IVUS (blue arrow). f Cross-sectional image from the distal position (operator’s position). The IVUS wire and transducer coincided with LAO 15° and RAO 30° was maximally separated of IVUS and target plaque. The IVUS wire was on the surface side of the transducer, and the target plaque was on the right side of the IVUS catheter. g The second guidewire was advanced a few millimeters to the right of IVUS on the angiography (white arrow). h, i By rotating RAO 30° on the IVUS image to 6 o’clock according to the direction of guidewire advancement, the angiographic image and the IVUS image were visually matched. The IVUS catheter was in the subintimal space. The second guidewire was advanced a few millimeters to the right of the IVUS catheter on angiography, and the right blue arrow shows that the second guidewire could be advanced almost into the center of the target intraplaque space in the IVUS image. j The second guidewire could be passed through the chronic total occlusion lesion. k, l We dilated the drug-coated balloon. Final angiography showed a good outcome. m Positional relationship between patient and operator and direction of IVUS