Intravascular ultrasound complements the diagnostic capability of carbon dioxide digital subtraction angiography for patients with allergies to iodinated contrast medium.

Carbon dioxide digital subtraction angiography (CO(2)DSA) is a useful and safe alternative for patients with renal dysfunction or allergies to iodinated contrast medium. However, CO(2)DSA image quality is worse than that of angiography with iodinated contrast medium, primarily because of movement during imaging and stent struts. In angioplasty of arteries of the lower extremities, CO(2)DSA cannot be used to sufficiently evaluate target lesions and determine the most efficient intervention. However, in the current case report, we describe a patient with severe allergies to iodinated contrast medium (Stevens-Johnson syndrome), because of which we were unable to use any iodinated contrast medium when conducting angioplasty. Therefore, we used intravascular ultrasound (IVUS), which facilitated the complete observation of the target lesion after stent implantation without requiring iodinated contrast medium. In this case, IVUS was used to complement the diagnostic capabilities of CO(2)DSA.