Peripheral arterial occlusive disease is a chronic and progressive disease that is common in the Western world. The diagnosis can usually be made from the patient’s medical history, a clinical examination, and Doppler index measurements. Exact visualization of the extent and severity of disease is, however, mandatory prior to treatment.
The gold standard for visualizing peripheral arterial occlusive disease is intra-arterial digital subtraction angiography (DSA). Although this modality offers high temporal and spatial resolution, it is also invasive, costly, and involves exposure to ionizing radiation.
CT angiography (CTA) has emerged as a noninvasive alternative to DSA for the depiction of vascular anatomy and pathology.1 The spatial resolution of vascular examinations has improved following the introduction of 64-row scanners. It is now possible to resolve objects as small as 0.4 mm in the x, y, and z planes. Visualizing small and moving arteries requires rapid image acquisition. The use of 64-slice CT has helped reduce the time needed to obtain a single slice of CT data.2
THE RIGHT TECHNIQUE
An optimal examination protocol for multislice CTA should ensure sufficient arterial enhancement throughout the arterial tree, pedal arteries included. This should be achieved without anticipating the bolus of contrast and without generating artifacts.3-7 An example of a standard protocol for performing CTA on a 64-slice system is shown in the table below.
It is important that the patient is comfortable on the CT table. She/he should be placed in a supine position with arms raised and feet rotated slightly to separate the tibia from the fibula (the trifurcation vessels from the bones). Cushions can be placed around the patient’s legs to stabilize them. The cushions may be strapped in position with adhesive tape if needed.
