Non-contrast Head CT |
- Preferred study at most centers due to widespread availability and rapid scan times
- Rule out intracranial hemorrhage or non-stroke lesions. Identify the degree of ischemic brain injury.
- Identify the vascular lesion responsible for the ischemic attack.
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CT Angiography (CTA) Head
CT Perfusion |
- Identifies patients with large vessel occlusion who may benefit from endovascular intervention
- Can be obtained concurrently with non-contrast head CT
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MRI with diffusion weighted imaging |
- Superior to non-contrast CT for the very early detection of acute ischemia and the exclusion of some conditions that mimic stroke.
- MRI can be used as the only imaging method in select centers with sufficient MRI availability for the evaluation of suspected stroke patients who do not have MRI contraindications.
- Limitations: Not readily available at most centers for the acute evaluation of patients with stroke; MRI in practice is more limited by patient contraindications or intolerance than CT; MRI is a longer study and may delay the administration of alteplase.
- There are no data to show that MRI is superior to CT for selecting patients who could be treated with intravenous thrombolysis.
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Oxygen saturation (O2 sat) |
- Rule out acute ischemic stroke associated with hypoxemia.
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Fingerstick blood glucose |
- Rule out hypoglycemia and hyperglycemia.
Serum glucose is the only lab test that must be measured before IV fibrinolytic therapy is started unless there is strong clinical suspicion for contraindication.
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Complete blood count (CBC)*
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- Check red blood cells (RBC), white blood cells (WBC), and platelets.
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Coagulation studies* |
- Check prothrombin time (PT), activated partial thromboplastin time (aPTT), international normalized ratio (INR), Ecarin clotting time, thrombin time, direct factor Xa assay.
Note: INR, aPTT, and platelets may be needed if coagulopathy is suspected, however fibrinolytic therapy should not be delayed while waiting for results.
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Cardiac biomarker* |
- Check troponin level to rule out myocardial infarction (MI).
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Electrocardiogram (ECG)* |
- Rule out acute MI and atrial fibrillation.
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Basic metabolic panel† |
- Check serum electrolytes, blood urea nitrogen (BUN), and creatinine.
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Blood alcohol & toxicology† |
- Include liver panel for patients with suspicion of alcohol intoxication.
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Arterial blood gas (ABG) † |
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Pregnancy test† |
- Assess women of child-bearing potential.
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Chest X-ray† |
- Assess for suspected lung disease or injury.
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Electroencephalogram† |
- Rule out ongoing seizures.
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Lumbar puncture† |
- Rule out suspected subarachnoid hemorrhage when brain imaging is negative (lumbar puncture will preclude IV fibrinolytic therapy, which should not be given if there is a suspicion for subarachnoid hemorrhage).
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Urinalysis† |
- Indicated if fever is present to check for infectious source.
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Blood cultures† |
- Indicated if fever is present to check for infectious source.
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Type and cross match† |
- Perform as needed if transfusion of blood products is anticipated.
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