Imaging Modalities for Severe Stenosis of Left Common Iliac Artery

Rationale for CTA as First-Line Imaging

The American College of Radiology recommends CT Angiography (CTA) of the abdomen and pelvis with bilateral lower extremity runoff as the best initial imaging modality for evaluating severe stenosis of the left common iliac artery, with sensitivity and specificity of 90-100% for detecting significant stenoses 1, 2, 3
CTA provides excellent visualization of vessel anatomy while being less invasive than conventional angiography, enabling comprehensive assessment of the entire vascular tree from the aorta through the lower extremities in a single examination 2
CTA offers volumetric (3D) imaging with extensive post-processing capabilities, including multiplanar reformatted and maximum-intensity projection images that create a detailed arterial road map 4

A multislice CT scanner should be used with collimation of 0.6 mm and reconstruction slice thickness between 0.5-1.0 mm for optimal imaging 5
Body-weight adapted injection of non-ionic iodinated contrast agent (≥350 mg/mL) using a power injector (≥4 mL/s) is recommended for CTA 5

The European Heart Journal states that MRA with contrast provides excellent soft tissue contrast and vascular assessment with sensitivity and specificity of 95% for diagnosing segmental stenosis and occlusion 6
MRA has limitations including longer acquisition times, potential contraindications in patients with certain implanted devices, and tendency to overestimate the degree of stenosis 6

The American College of Radiology recommends duplex ultrasound as an initial screening tool with sensitivity and specificity of approximately 90-95% for detecting stenoses >50% from the iliac to popliteal arteries 2, 3
Duplex ultrasound may underestimate the extent of disease when multiple "tandem" stenotic segments are present 2

The American College of Radiology states that DSA is now primarily reserved for cases where endovascular intervention is planned rather than for diagnostic purposes alone, due to its invasive nature and risks of catheterization complications 7, 6, 2
DSA provides the advantage of measuring pressure gradients across stenoses, which can be valuable for determining hemodynamic significance 7, 3

Initial assessment with ankle-brachial index (ABI) and duplex ultrasound to confirm presence of peripheral arterial disease is recommended by the American College of Radiology 3
CTA of abdomen and pelvis with bilateral lower extremity runoff as the primary imaging modality for comprehensive anatomic evaluation is recommended by the American College of Radiology 1, 2
Consider MRA as an alternative if CTA is contraindicated (e.g., severe renal impairment, contrast allergy), as stated by the European Heart Journal 6
Reserve DSA for cases where intervention is planned or when non-invasive imaging is inconclusive, as recommended by the American College of Radiology 7, 3