Aortoiliofemoral and Lower-Extremity CT Angiography

A practical radiology review of Aortoiliofemoral and Lower-Extremity CT Angiography, focused on imaging findings, differential diagnosis, reporting points, and high-yield teaching pearls.

• Purpose & Clinical Use
• CTA = rapid, comprehensive tool for PAD, trauma, post-EVAR, and infection.
• Evaluates inflow (aorta → iliacs), outflow (fem-pop), runoff (calf/foot)
• Guides revascularization, endovascular planning, or limb salvage.

Protocol Pearls

• kVp: 80–120 (↓kVp → ↑iodine attenuation)
• Contrast: ≥4 mL/s, bolus tracking (trigger 150 HU thoracic aorta).
• Coverage: diaphragm → toes.
• Delayed phase for bolus outrun / venous contamination.
• Dual-energy / PCD CT: virtual noncontrast, calcium removal, high-res 0.02 mm.

Anatomy & Collaterals

• Aorta → common iliac → internal/external iliac → CFA → SFA → popliteal → tibials.
• Key collaterals: Winslow pathway, cruciate anastomosis, deep femoral perforators.
• Recognize variants (persistent sciatic artery, popliteal branching).