Recommended Initial Imaging for Suspected Peripheral Vascular Disease
Duplex ultrasound is recommended as the first-line imaging method for the initial evaluation of suspected peripheral arterial disease (PAD). 1, 2
Diagnostic Algorithm for Suspected PAD
Step 1: Initial Non-Imaging Assessment
- Measure Ankle-Brachial Index (ABI)
- Abnormal: ≤0.90
- Borderline: 0.91-0.99
- Normal: 1.00-1.40
- Noncompressible: >1.40
- For patients with diabetes or renal failure with normal resting ABI, measure Toe Pressure (TP) or Toe-Brachial Index (TBI) 1
Step 2: First-Line Imaging
- Duplex ultrasound is the recommended initial imaging modality 1, 2
- Advantages: Non-invasive, no radiation exposure, no contrast required, high diagnostic accuracy
- Provides both anatomic information about stenosis/occlusion and physiological data
- Can assess vessel wall and plaque morphology 3
Step 3: Advanced Imaging (if needed)
- For patients with aorto-iliac or multisegmental/complex disease requiring revascularization:
Special Considerations
When to Use CTA or MRA Instead of Duplex Ultrasound
- Planning revascularization procedures
- Complex or multisegmental disease assessment
- Aorto-iliac disease evaluation
- Suspected vascular trauma (CTA preferred) 1, 2
- When ultrasound is impractical (e.g., excessive subcutaneous tissue, leg casting) 1
Specific Clinical Scenarios
- For suspected popliteal entrapment syndrome: Duplex ultrasound, CTA, or MRA are all appropriate initial options 1
- For suspected external iliac artery endofibrosis: Duplex ultrasound, CTA, or MRA are all appropriate initial options 1
- For vascular trauma: CTA is the preferred first-line investigation 1, 2
Limitations and Cautions
- CTA requires contrast and exposes patients to radiation, making it unsuitable for patients with renal insufficiency 2
- MRA is contraindicated in patients with certain metallic implants and may be impractical in unstable patients 1
- Duplex ultrasound accuracy is operator-dependent, but when performed by well-trained operators, it shows excellent diagnostic concordance with DSA (digital subtraction angiography) 4
Key Point
Always analyze imaging test results in conjunction with clinical symptoms and hemodynamic tests before proceeding with any invasive procedure 1. The diagnostic approach should prioritize non-invasive methods first, reserving more invasive techniques for treatment planning or when initial imaging is inconclusive.