Computed tomography angiography of the lower limbs or CT angiography of the lower limbs is an imaging method that examines the vascular system using high-intensity X-rays. Contrast dye is injected into the arterial system from the femoral artery to the iliac artery triad, then X-rayed to take pictures of each cross-sectional vessel and reconstruct the image of the vascular system in three-dimensional space.