In an older patient with transient ischemic attack and risk factors (hypertension, hyperlipidemia, diabetes, smoking, peripheral vascular disease), should I order a CT angiogram of the brain, cervical carotid arteries, and aortic arch to evaluate for high‑grade carotid stenosis and aortic arch occlusion?

CT Angiography for TIA Evaluation with Multiple Vascular Risk Factors

Yes, order a CT angiogram of the head, neck (cervical carotid arteries), and aortic arch immediately—this patient's TIA with multiple atherosclerotic risk factors (hypertension, hyperlipidemia, diabetes, smoking, peripheral vascular disease) requires urgent comprehensive vascular imaging to identify high-grade carotid stenosis or occlusion that directly determines stroke prevention strategy and need for revascularization. 1

Rationale for Comprehensive Vascular Imaging

Why Vascular Imaging is Critical After TIA

• The stroke risk following TIA is extremely high: 8.8% at 7 days and 11.6% at 90 days, with symptomatic carotid disease carrying a 20.1% risk of ipsilateral stroke at 90 days 1
• Direct correlation exists between degree of carotid stenosis and stroke risk, which drives the decision for carotid endarterectomy or stenting 1
• Evaluation of patients with carotid territory TIA requires rapid vascular imaging of the cervical carotid arteries in addition to brain parenchymal imaging 1
• Vascular imaging must be performed to evaluate stroke mechanism and assess future stroke risk 1

Your Patient's High-Risk Profile

• Patients with peripheral vascular disease have a 57% prevalence of ≥30% carotid stenosis, with 25% being potential surgical candidates 2
• Multiple atherosclerotic risk factors (hypertension, diabetes, hyperlipidemia, smoking) significantly increase the likelihood of significant carotid disease 3, 2
• Polyvascular disease is seen in 45% of patients with known atherosclerotic disease, making comprehensive evaluation essential 3

Recommended Imaging Protocol

CT-Based Approach (Most Practical)

Perform CTA covering the entire cerebrovascular axis from aortic arch through intracranial vessels in a single acquisition: 1

• Noncontrast CT head to exclude hemorrhage and identify early ischemic changes 1
• CTA head with IV contrast to evaluate intracranial vessels for occlusion or stenosis 1
• CTA neck with IV contrast to assess cervical carotid and vertebral arteries 1
• CTA aortic arch to evaluate proximal vessel origins and arch atherosclerosis, which is required before endovascular therapy 1

Why This Comprehensive Approach

• CTA has 100% sensitivity and 100% negative predictive value for ≥70% carotid stenosis, making it an excellent screening test 4
• Imaging of the aortic arch and proximal cervical arteries is required before endovascular therapy to ascertain feasibility of intervention 1
• A helical scan from vertex to aortic arch during contrast injection provides complete vascular assessment in one study 1

Alternative MRI-Based Protocol (If Immediately Available)

If MRI can be performed rapidly on a 24/7 basis: 1, 5

• MRI brain with DWI (superior for detecting acute ischemia, 77% sensitivity vs. 16% for CT) 5
• MRA head without contrast for intracranial vessels 5
• MRA neck with contrast for superior visualization of vertebral artery origins and extracranial segments 5

Confirmatory Testing Strategy

If CTA demonstrates ≥70% stenosis, correlation with a second noninvasive modality is recommended before revascularization: 1, 6

• Carotid duplex ultrasonography provides concordant results and uses peak systolic velocity to grade stenosis 1, 3
• Concordant results from two noninvasive imaging techniques can determine treatment eligibility for revascularization without catheter angiography 1
• Reserve catheter angiography only for discordant noninvasive results or when definitive diagnosis cannot be established 1

Critical Pitfalls to Avoid

• Do not perform only brain parenchymal imaging without vascular imaging—this misses critical carotid stenosis that determines treatment strategy 1, 5
• Do not delay vascular imaging beyond 48 hours of symptom onset for TIA patients who are intervention candidates 1, 5
• Do not use catheter angiography as initial test due to invasive nature and procedural risks when noninvasive imaging is diagnostic 1
• Do not rely on ultrasound alone if it shows ≥70% stenosis—obtain confirmatory CTA or MRA before surgical planning 6

Timing Considerations

• Complete initial imaging within 24-48 hours of symptom onset given the high early stroke risk 5
• Expeditious initial imaging is important because stroke risk is highest in the first week after TIA 1
• Screening CT should ideally be performed no longer than 1 hour before initiating any thrombolytic therapy if acute stroke develops 1