OBJECTIVE. The development of collateral pathways for arterial blood flow is common in the presence of atherosclerotic occlusive disease of the abdominal aorta and iliac arteries. The collateral pathways are divided into systemic-systemic and systemic-visceral pathways. MDCT is commonly used to evaluate aortic stenosis and the resulting collateral pathways. CONCLUSION. Common and rare arterial collateral pathways are reviewed by 3D volume-rendered CT images. Visceral and lower extremity arterial embryology is reviewed. © American Roentgen Ray Society.