CT angiography and 3D imaging in aortoiliac occlusive disease: collateral pathways in Leriche syndrome.

Collateral pathways in aortoiliac occlusive disease are essential for arterial blood flow to the abdomen, pelvis, and lower extremities. These pathways can be broadly divided into systemic-systemic, visceral-visceral, and systemic-visceral collateral networks. MDCT angiography is the most commonly used modality for the diagnostic evaluation of patients with aortoiliac occlusive disease, allowing excellent evaluation of stenotic arterial segments, as well as beautifully illustrating resulting collateral pathways (particularly when utilizing 3D reconstruction techniques). This article seeks to familiarize radiologists with the most common patterns of aortoiliac occlusion and associated arterial collateral pathways utilizing CT angiography.