What is the management of an incidental acute stroke found on an outpatient Magnetic Resonance Imaging (MRI) brain scan?

Management of Incidental Acute Stroke on Outpatient MRI Brain

Patients with incidental acute stroke found on outpatient MRI brain should be immediately referred to the nearest emergency department with stroke capabilities for urgent evaluation and management, regardless of symptoms. 1

Initial Assessment and Triage

• When an acute stroke is incidentally discovered on outpatient MRI:
  • Contact the patient immediately
  • Direct them to the nearest emergency department with stroke capabilities
  • Send the MRI results to the receiving facility
  • Consider emergency medical services transport if:
    • Any neurological symptoms are present
    • The lesion is large or in a critical location
    • The patient has significant risk factors

Emergency Department Evaluation

1. Immediate Clinical Assessment:

   • Airway, breathing, circulation evaluation 1
   • Neurological examination with standardized stroke scale (NIHSS) 1
   • Assessment of vital signs: heart rate, blood pressure, temperature, oxygen saturation 1

2. Laboratory Evaluation (should not delay treatment):

   • Complete blood count
   • Coagulation studies (INR, aPTT)
   • Electrolytes
   • Blood glucose
   • Renal function 1

3. Additional Imaging:

   • CT angiography (CTA) of head and neck to identify potential large vessel occlusions 1
   • Consider CT perfusion if within potential treatment window 1
   • Evaluate for hemorrhagic transformation 1

Treatment Decision Algorithm

If Patient Presents Within Treatment Window (≤4.5 hours from last known well):

1. Assess for IV thrombolysis eligibility:

   • No contraindications (no hemorrhage, BP <185/110 mmHg, etc.)
   • If eligible, administer IV alteplase 0.9 mg/kg (max 90 mg) with 10% as bolus and 90% as 60-minute infusion 2

2. Assess for endovascular thrombectomy eligibility:

   • Large vessel occlusion present on CTA
   • If eligible, proceed with mechanical thrombectomy (can be considered up to 24 hours with favorable imaging) 2

If Patient Presents Outside Treatment Window (>4.5 hours):

1. Consider extended window treatments:

   • Evaluate for CT/MRI perfusion mismatch (potentially salvageable tissue)
   • If favorable imaging, may still be eligible for IV thrombolysis (4.5-9 hours) or thrombectomy (up to 24 hours) 2

2. If not eligible for acute reperfusion therapy:

   • Initiate secondary stroke prevention
   • Admit for monitoring and further workup

Diagnostic Workup for Stroke Etiology

1. Vascular Imaging:

   • CTA or MRA of intracranial and cervical vessels to identify stenosis/occlusion 1

2. Cardiac Evaluation:

   • Electrocardiography immediately
   • Echocardiography (at least transthoracic) 1
   • Consider prolonged cardiac monitoring (telemetry or Holter) 1

3. Additional Testing Based on Clinical Suspicion:

   • Hypercoagulable workup (especially in younger patients)
   • Inflammatory markers if vasculitis suspected
   • Toxicology screening if drug use suspected 1

Hospitalization Criteria

Hospitalize patients with incidental acute stroke on MRI if 1:

• Presentation is within 72 hours of the event AND any of:
  • Evidence of acute cerebral infarction on imaging
  • Large artery atherosclerosis found on vascular imaging
  • Abnormal cardiac evaluation
  • Recurrent episodes (crescendo TIAs)
  • Inability to provide expedited outpatient follow-up

Common Pitfalls to Avoid

1. Delaying treatment while waiting for additional tests beyond necessary neuroimaging 2

2. Dismissing the significance of incidental findings, especially small infarcts, which may indicate a higher risk for future larger strokes 3

3. Failing to complete a comprehensive vascular evaluation - even asymptomatic patients require thorough evaluation of stroke etiology 1

4. Overreliance on symptom severity - absence of symptoms does not indicate low risk; silent infarcts are associated with future stroke risk 1

5. Not initiating secondary prevention - all patients with acute infarcts require appropriate antithrombotic therapy and risk factor management 4

By following this algorithm, clinicians can ensure appropriate management of incidentally discovered acute strokes, potentially preventing disability from stroke progression and reducing the risk of future cerebrovascular events.