First Test to Order in the Emergency Department
For a 70-year-old patient presenting with acute-to-subacute ischemic stroke after recent surgery, the first test to obtain is non-contrast CT of the head to exclude hemorrhage and assess for early ischemic changes. 1
Rationale for Non-Contrast CT as First-Line
Non-contrast CT (NCCT) remains the most practical and widely available imaging modality that can be completed within 25 minutes of ED arrival and interpreted within 45 minutes, which is critical for time-sensitive treatment decisions 1
The primary goal is to differentiate ischemic from hemorrhagic stroke, as this distinction is absolutely essential before any antithrombotic or thrombolytic therapy can be considered 1, 2
CT is specifically required to exclude intracranial hemorrhage, which would be an absolute contraindication to thrombolytic therapy and would fundamentally change management 1
Post-surgical patients have elevated bleeding risk, making hemorrhage exclusion even more critical before proceeding with any stroke treatment 1
Concurrent Laboratory Testing (Do Not Delay Imaging)
While obtaining the CT scan, the following laboratory tests should be drawn simultaneously:
Blood glucose to exclude hypoglycemia as a stroke mimic, which requires immediate exclusion before other interventions 1, 2, 3
Complete blood count with platelet count to detect thrombocytopenia, anemia, or polycythemia affecting treatment decisions 1, 2, 3
Coagulation studies (PT/INR, aPTT) are critical before thrombolytic therapy, especially in post-surgical patients 1, 3
Electrolytes and renal function (creatinine, eGFR) to identify metabolic derangements and guide medication dosing 1, 2
Troponin to identify concurrent myocardial infarction or ischemia, as acute MI can cause stroke and stroke can precipitate cardiac ischemia 1, 3
12-lead ECG to assess cardiac rhythm, detect atrial fibrillation, and identify structural heart disease 1, 3
Immediate Follow-Up Vascular Imaging
After the non-contrast CT confirms ischemic stroke, CT angiography (CTA) from aortic arch to vertex should be performed immediately to assess both extracranial and intracranial circulation and identify large vessel occlusions that may benefit from endovascular therapy 1, 2
CTA can be performed at the same time as the initial brain CT and is the ideal way to assess the entire cerebrovascular system in one session 1
Vascular imaging identifies large vessel occlusions that may be amenable to mechanical thrombectomy up to 24 hours from symptom onset 1, 2
Critical Timing Considerations
The entire initial imaging evaluation (NCCT + CTA) should be completed as rapidly as possible, ideally with CT interpretation within 45 minutes of ED arrival 1
Do not delay CT imaging while awaiting laboratory results unless there is clinical suspicion of bleeding abnormality, thrombocytopenia, or known anticoagulant use 1, 3
Advanced imaging (MRI, CT perfusion) should not delay treatment decisions if the patient is within the thrombolytic window 1
MRI as Alternative (If Immediately Available)
MRI with diffusion-weighted imaging (DWI) is the preferred imaging modality if immediately available without delaying care, as it provides superior sensitivity for acute ischemia 1
However, CT is more practical in most emergency settings due to faster acquisition time, wider availability, and fewer contraindications in post-surgical patients 1
Common Pitfalls to Avoid
Never accept a delay in neuroimaging while waiting for laboratory results unless anticoagulation status is uncertain or bleeding disorder is suspected 1, 3
Do not skip vascular imaging after the initial CT, as identifying large vessel occlusions changes management even beyond the IV thrombolysis window 1, 2
Do not forget to check glucose immediately, as it is the only stroke mimic requiring immediate exclusion before proceeding 2, 3
In post-surgical patients, be especially vigilant about hemorrhage risk and ensure coagulation studies are obtained before any antithrombotic therapy 1