RadteraCTA Abdomen/Pelvis with Lower Extremity Runoff
CTA+ ContrastVascular
Indications
- Peripheral arterial disease / claudication, critical limb ischemia
- Acute limb ischemia, trauma, post-bypass/stent surveillance
- Pre-procedural mapping for revascularization
Patient prep
- 18-20G IV antecubital
- Assess renal function (long Z-coverage, larger contrast load)
- Feet first, legs together and immobilized to avoid motion across long acquisition
Contrast
Agentiodinated (iohexol 350 / iopamidol 370)
RouteIV
Dose100-150 mL at 4-5 mL/s + saline chase (biphasic injection often used)
TimingBolus tracking in supra/infrarenal aorta (~100-150 HU trigger); single arterial sweep from diaphragm to feet timed to follow the bolus; consider slower table speed or fixed delay; optional delayed acquisition of calves/feet if distal opacification is poor
Technique
- Supine, feet first, legs together; coverage from above renal/celiac axis through toes
- 120 kV (100 kV in thin patients to boost iodine); dose modulation
- Sub-mm collimation; table speed matched to bolus to keep up with arterial flow (avoid outrunning bolus)
- Recon 0.625-1 mm; bone removal / dual-energy may aid
- Add delayed phase to distal legs/feet if runoff vessels under-opacified
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Axial arterial source | axial | 0.625-1 mm | Thin for 3D/MIP |
| 2 | Coronal/Sagittal MIP | coronal/sagittal | thick MIP | Inflow and runoff |
| 3 | 3D VR / bone-removed | 3D | VR | Full-length runoff map |
| 4 | Curved planar reformats | oblique | thin | Stenosis quantification per vessel |
Key points
- Bolus timing is the main challenge: slow flow in PAD can cause the table to outrun the bolus, leaving calves unopacified—use slower acquisition or add distal delayed run
- Asymmetric flow (one occluded side) makes single timing imperfect; tailor to symptomatic limb
- Dual-energy/automated bone removal speeds heavily calcified runoff interpretation
- Watch total iodine dose given long coverage; use lower kV to reduce volume
- Include inflow (aortoiliac) to identify proximal disease
References
• ACR-NASCI-SIR-SPR Practice Parameter for the Performance and Interpretation of Body CTA
• ACR Appropriateness Criteria: Lower Extremity Arterial Disease
• Radiopaedia: CT angiography lower limb ( link
• ACR Appropriateness Criteria: Lower Extremity Arterial Disease
• Radiopaedia: CT angiography lower limb ( link
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.