From the Guidelines
When evaluating lower extremity arterial disease, Arterial Doppler ultrasound should be the initial test for suspected peripheral arterial disease (PAD), claudication symptoms, or post-revascularization surveillance, while CTA runoff is preferred for planning revascularization procedures, evaluating acute limb ischemia, or assessing complex anatomical disease. This approach is supported by the most recent guidelines, including the 2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS guideline for the management of lower extremity peripheral artery disease 1.
Clinical Context Considerations
When deciding between these two tests, consider the clinical context and patient factors, such as the presence of kidney disease, which may contraindicate the use of iodinated contrast in CTA 1. Arterial Doppler ultrasound is non-invasive, radiation-free, and relatively inexpensive, providing functional hemodynamic information including ankle-brachial indices (ABIs) and waveform analysis.
Choosing the Right Test
- For patients with suspected PAD, start with Arterial Doppler ultrasound and progress to CTA if intervention is being considered or if the Doppler results don't fully explain the clinical presentation.
- In acute limb ischemia, proceed directly to CTA if the patient is stable enough for the study, as immediate anatomical information is crucial for urgent treatment planning 1.
- CTA provides superior anatomical detail of the entire arterial tree from abdomen to feet in a single examination but involves radiation exposure and iodinated contrast.
Evidence-Based Recommendations
The American College of Cardiology/American Heart Association joint committee on clinical practice guidelines recommends the use of duplex ultrasound, computed tomography angiography (CTA), magnetic resonance angiography (MRA), or catheter angiography of the lower extremities for assessment of anatomy and severity of disease in patients with functionally limiting claudication with inadequate response to guideline-directed medical therapy (GDMT) for whom revascularization is being considered 1.
Limitations and Considerations
While CTA is a valuable tool, its use may be limited in patients with heavily calcified atheromatous disease, which can limit the ability to interpret CT images, particularly in tibial arteries 1. Dual-energy CTA can reduce blooming and beam-hardening artifact created by heavily calcified atheromatous disease and metallic stents 1.
Final Considerations
In summary, the choice between Arterial Doppler ultrasound and CTA runoff should be guided by the clinical context, patient factors, and the specific goals of the evaluation, with a preference for starting with non-invasive, radiation-free tests like Arterial Doppler ultrasound for initial assessments and reserving CTA for more complex cases or when intervention is being considered 1.
From the Research
Arterial Doppler of Lower Extremities vs CTA Runoff
When deciding between arterial Doppler of lower extremities and CTA runoff, several factors should be considered:
- The patient's symptoms and medical history, as patients with suspected peripheral arterial disease (PAD) may require different diagnostic approaches 2
- The severity and extent of the disease, as noninvasive vascular testing can confirm the diagnosis and determine the severity of PAD 3
- The need for rapid diagnosis and early initiation of therapy, as CTA offers a rapid and accurate means to diagnose and grade the extent of vascular disease in the acute care setting 4
Indications for Arterial Doppler and CTA Runoff
- Arterial Doppler is often used as an initial diagnostic test for patients with suspected PAD, as it is noninvasive and can provide information on blood flow and vessel morphology
- CTA runoff is typically used for patients with more severe symptoms or those who require more detailed imaging of the vascular system, such as patients with intermittent claudication or suspected musculoskeletal pathologies 5
- CTA runoff can also be used to guide specific therapy and predict technical success of endovascular revascularization in the superficial femoral and popliteal artery 6
Factors to Consider When Ordering CTA Runoff
- The presence of 100% vessel calcification, which is a significant predictor of technical failure of endovascular revascularization 6
- The length of occlusion, which can also be associated with technical failure 6
- The need for evaluation of musculoskeletal pathologies and clinically relevant extravascular incidental findings, as CTA can provide sufficient image quality for evaluation of the musculoskeletal system 5