Imaging for Suspected Iliac Artery Disease

Introduction to Diagnostic Approaches

The American College of Radiology recommends ordering a CTA abdomen and pelvis with bilateral lower extremity runoff with IV contrast to evaluate for iliac artery occlusive disease, and performing an exercise/treadmill ABI at the same time, as resting ABIs are frequently normal in isolated iliac disease 1, 2

The American College of Radiology gives CTA a moderate recommendation as the definitive imaging modality because cross-sectional imaging allows precise diagnosis of anatomic disease location and significance of stenosis/occlusion, which directly improves surgical planning for endovascular or open surgical revascularization 1, 2
CTA provides complete anatomic detail from the aorta through the lower extremities in a single study, enabling accurate identification of the location and severity of stenosis/occlusion, and determining suitability for endovascular versus surgical intervention 1, 2

ABIs may be completely normal at rest in patients with isolated iliac occlusive disease, making exercise/treadmill ABIs essential for objectively evaluating functional limitations, as resting ABIs miss isolated aortoiliac disease, and exercise ABIs unmask hemodynamically significant proximal disease that appears normal at rest 1, 2, 3
Exercise ABIs provide objective documentation of functional impairment, which is crucial for diagnosis and treatment planning 1, 2

If CTA cannot be performed, duplex ultrasound of the bilateral lower extremities including iliac segments is an acceptable alternative with 92% sensitivity and 96% specificity for detecting significant aortoiliac lesions, according to the American College of Radiology 1, 2, 4
Duplex ultrasound has excellent negative predictive value (97-100%) for the iliac segment, meaning a negative study reliably excludes significant disease, but positive predictive value ranges from only 60-89%, so positive findings may require CTA confirmation 1, 2

The American College of Radiology advises against relying on resting ABI alone, as isolated iliac disease frequently presents with normal resting ABIs but becomes apparent only with exercise testing 1, 2, 3

The European Society of Cardiology recommends considering the technical challenges of duplex ultrasound in the iliac arteries, which reduce diagnostic accuracy, with excellent overall specificity of 95% for detecting >50% stenosis in peripheral arterial disease, but with unique challenges in the iliac segment 5, 6, 7, 8
Operator dependence is a critical factor in duplex ultrasound reliability, fundamentally depending on the sonographer's expertise, according to the European Heart Journal 5, 6, 7, 8