Acute Stroke Evaluation and Management Based on Non-Contrast Head CT
Non-contrast head CT is the essential first imaging study for any patient with suspected acute stroke, primarily to exclude intracranial hemorrhage before initiating any reperfusion therapy. 1, 2
Initial Imaging Approach
Obtain emergent non-contrast CT head immediately for all patients presenting with acute stroke symptoms. This single study serves multiple critical functions 2:
- Excludes intracranial hemorrhage (absolute contraindication to thrombolysis)
- Identifies early ischemic changes and extent of infarction
- Rules out stroke mimics (masses, infection)
- Guides treatment eligibility decisions
Optimizing CT Interpretation
View images using specialized "stroke windows" (not just standard brain windows) to significantly improve detection of early ischemic changes—sensitivity increases from 18% to 70% 3. Look specifically for:
- Hyperdense vessel sign (MCA or basilar artery)
- Loss of gray-white differentiation
- Sulcal effacement
- Basal ganglia or insular ribbon hypodensity
Use ASPECTS scoring (Alberta Stroke Program Early CT Score) to quantify infarct extent systematically. ASPECTS ≤7 indicates larger infarct with higher hemorrhage risk and worse functional outcomes 4, 5.
Immediate Management Algorithm
If CT Shows No Hemorrhage:
1. For patients within 4.5 hours of symptom onset:
- Administer IV alteplase 0.9 mg/kg (max 90 mg) over 60 minutes, with 10% as initial bolus 1
- Do NOT wait for additional vascular imaging if within the standard window
2. For wake-up or unknown onset strokes:
- Non-contrast CT alone is sufficient to safely guide thrombolysis decisions when clinical-imaging mismatch exists (symptomatic ICH rate only 1-2.1%, comparable to standard window patients) 6
- This approach is particularly valuable when advanced imaging (MRI/perfusion) is unavailable
3. For suspected large vessel occlusion (LVO):
- Proceed directly to CTA head and neck after non-contrast CT 2
- CTA is the fastest method to confirm LVO (sensitivity/specificity both high)
- In select cases with clear LVO signs (hyperdense MCA sign) and obvious etiology (new atrial fibrillation), consider proceeding directly to angiography suite after non-contrast CT to minimize door-to-reperfusion time 2
Post-Thrombolysis Monitoring Protocol 1:
- Admit to ICU or stroke unit
- Blood pressure checks every 15 minutes during and for 2 hours after infusion
- Then every 30 minutes for 6 hours, then hourly until 24 hours
- Maintain BP ≤180/105 mmHg
- Neurological assessments on same schedule
- Delay invasive procedures (NG tubes, Foley catheters) if safely possible
- Repeat CT at 24 hours before starting anticoagulants or antiplatelets
Critical Pitfalls to Avoid
Do not skip non-contrast CT even if planning immediate thrombectomy—hemorrhage must be excluded first 1, 2.
Do not delay thrombolysis to obtain perfusion imaging or MRI in standard window patients—every minute counts.
Do not dismiss subtle early ischemic changes—use stroke windows and systematic ASPECTS scoring to avoid missing findings 3.
If clinical deterioration occurs: Stop alteplase immediately, obtain emergent repeat CT, check coagulation studies, and prepare for hemorrhage management with cryoprecipitate (10 units), tranexamic acid (1000 mg IV), and consult neurosurgery 1.
Extended Window Considerations (6-24 Hours)
For patients 6-24 hours from last known normal with confirmed LVO on CTA, CT perfusion may be needed to determine thrombectomy eligibility, though this represents a specific subset requiring advanced imaging 2. The non-contrast CT remains the mandatory first step.
Vascular Imaging Timing
CTA head and neck should be obtained rapidly alongside or immediately after non-contrast CT in 2:
- All suspected LVO cases
- TIA or minor stroke patients (within 48 hours for carotid evaluation)
- Any patient being considered for endovascular therapy
The combination of non-contrast CT + CTA can be completed in minutes and provides sufficient information for most acute treatment decisions.