What is the appropriate management and secondary‑prevention strategy for a patient with chronic infarcts on a cranial CT scan?

Management of Chronic Infarcts on Cranial CT Scan

For patients with chronic infarcts on CT, the priority is aggressive secondary stroke prevention through vascular imaging to identify treatable stenosis, antiplatelet therapy, and risk factor modification—surveillance imaging focuses on detecting complications like hemorrhagic transformation rather than routine monitoring of stable infarcts.

Initial Vascular Assessment

The discovery of chronic infarcts mandates comprehensive evaluation of cerebrovascular anatomy to identify treatable causes and prevent recurrent events:

• Perform noninvasive cervical carotid imaging within 48 hours using either carotid duplex ultrasound, CTA neck, or MRA neck to identify significant stenosis that may warrant revascularization 1
• Obtain intracranial vascular imaging with CTA head or MRA head to detect intracranial atherosclerotic disease or other steno-occlusive lesions 1
• Carotid duplex ultrasound is highly accurate for assessing stenosis degree and avoids contrast/radiation exposure, making it ideal for serial monitoring 1
• CTA may overestimate stenosis in heavily calcified vessels, so correlation with duplex ultrasound is valuable when findings are discordant 1

Surveillance Imaging Strategy

Avoid routine surveillance CT in stable chronic infarcts—imaging should be targeted to specific clinical concerns:

• CT head without contrast is appropriate when monitoring for complications such as hemorrhagic transformation or mass effect in recent infarcts (within days to weeks) 1
• MRI without or with contrast serves as an alternative for parenchymal assessment and is superior for detecting small or posterior fossa infarcts 1
• Do not use IV contrast for routine surveillance as contrast enhancement in subacute infarcts can paradoxically mimic hemorrhagic conversion or aggressive lesions 1
• Serial imaging is most relevant for large hemispheric or cerebellar infarcts at risk for delayed swelling, not for stable chronic infarcts 1

The peripheral "penumbra" zone around chronic infarcts may show moderate perfusion reduction (13-19% below normal) and can extend over 30% of a hemisphere, potentially correlating with neurological status 2. However, this does not justify routine perfusion imaging in the chronic phase.

Secondary Prevention Priorities

Antiplatelet Therapy

• Initiate aspirin 160-300 mg daily within 48 hours of identifying acute or subacute infarction 3
• Continue long-term antiplatelet therapy for secondary prevention 1

Risk Factor Management

• Obtain cardiac evaluation including ECG and echocardiography to identify cardioembolic sources 1, 3
• Assess lipid panel, glucose, renal function, and blood pressure 3
• The presence of chronic infarcts on CT correlates with increased risk of subsequent stroke, particularly when associated with diminished collateral reserve 4

Carotid Revascularization Considerations

• Patients with symptomatic carotid stenosis ≥50% should be evaluated for carotid endarterectomy or stenting 1
• Timing is critical—intervention within 2 weeks of symptoms provides maximum benefit for symptomatic stenosis 1

Critical Pitfalls to Avoid

• Never perform CT perfusion for routine surveillance of chronic infarcts without known steno-occlusive lesions—there is no supporting literature for this practice 1
• Avoid cerebral angiography as initial evaluation—reserve it for cases where noninvasive imaging is indeterminate or when endovascular intervention is planned 1
• Do not delay vascular imaging—the early recurrent stroke risk is highest in the first 48-90 days, with 20.1% risk at 90 days for carotid territory events 1
• Recognize that normal initial CT does not exclude significant ischemia—this typically occurs in the earliest presentations (mean 4.5 hours) and oldest patients 5

When to Escalate Imaging

Obtain urgent repeat imaging if:

• New neurological symptoms develop suggesting recurrent stroke 1
• Clinical deterioration occurs suggesting hemorrhagic transformation 1
• Large infarcts show signs of mass effect or midline shift requiring neurosurgical evaluation 6, 3

The extent of chronic infarction visible on CT correlates with future stroke risk regardless of chronicity, making comprehensive vascular evaluation mandatory rather than optional 1.