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CTA Lower Extremity Runoff for PAD

Last Updated: 2026-01-01 Author:

  • 1. Clinical Summary

    Series Phase Coverage
    Non-contrast Non-contrast Diaphragm to Toes
    CTA Arterial Arterial (bolus tracked) Above the diaphragm to Toes
    CTA Runoff Immediately after CTA Knees to Toes
    • Peripheral arterial disease
    • Claudication
    • Critical limb ischemia
    • Pre-operative bypass planning

  • 2. Patient Prep

    • Position: Supine with arms raised. Legs straight
    • NPO Status: NPO 2-4 hours

  • 3. IV Contrast & Injection

    Parameter Value
    Agent Isovue 370
    Volume 1.9 mL/kg
    Flow Rate 3-4 mL/s
    Duration 35s (5s fast 5-6mL/s then 30 s slow 3-4mL/s)
    Timing Method Bolus Tracking
    ROI Placement Abdominal aorta
    Trigger (HU) 150 HU

    Use full dose if GFR > 30

    If GFR < 30

    Max Contrast = \(2*\left[\frac{\text{Patient Weight}}{75 \text{ kg}} * \text{eGFR}\right]\)

  • 4. Special Notes

    • Scan from diaphragm to toes. Tape feet together. Use automatic bolus tracking. Extend delay if known severe PAD. Cover tibial vessels to ankle
    • Additional Recons: MIP and 3D VR. Curved MPR of each arterial segment. Bone subtraction for vessels.
    • 18-20G IV antecubital, flow rate up to 6 mL/s

    Safety First

    • Renal Function: Verify eGFR > 30
    • Allergy: Check allergy history
    • Assess aortoiliac femoral popliteal and tibial vessels. Grade stenoses. Identify occlusions. Assess runoff vessels
    • Ensure legs are straight and not rotated. Remove shoes and metal
Series Name Start Location End Location Delay Slice Thickness Notes
Scout/Topogram Renal arteries Feet N/A N/A AP full legs
CTA Arterial Renal arteries Ankle Bolus tracked 0.625 mm May need slower table speed if severe PAD
CTA Runoff Mid Thigh Foot Immediately after CTA 0.625 mm Runoff phase to evaluate distal vessels
Plane Acquisition FOV Thickness/Increment Kernel IR Strength Notes
Axial Arterial Pelvis/Legs 2 mm/2 mm Vascular 3 Assess all vessel segments
Coronal Arterial Full legs 3 mm/3 mm Vascular 3 MIP full arterial tree
Sagittal Arterial Full legs 3 mm/3 mm Vascular 3 Lateral views of vessels
3D VR Arterial Full legs 1.5 mm source Vascular 3 3D for surgical planning