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Zorluk: ZorOrdering Imaging Studies

A 68-year-old man is brought to the emergency department with sudden-onset right-sided hemiparesis, facial droop, and global aphasia. His symptoms were first noticed by his wife 8 hours ago, and he was last known to be at his baseline 10 hours ago. His blood pressure is 165/90 mmHg, and his pulse is 88/min and irregularly irregular. Suspecting an acute ischemic stroke, the stroke team is activated to evaluate the patient for potential mechanical thrombectomy.

Arrange the following neuroimaging modalities in the most appropriate chronological sequence for the evaluation and management of this patient, from initial emergency department presentation to definitive subacute post-treatment follow-up.

  1. 1Non-contrast computed tomography (CT) of the head
  2. 2Computed tomography angiography (CTA) of the head and neck
  3. 3Computed tomography (CT) perfusion imaging
  4. 4Magnetic resonance imaging (MRI) of the brain without contrast

Cevap

The correct sequence is: Non-contrast CT of the head, followed by CTA of the head and neck, followed by CT perfusion imaging, and finally an MRI of the brain.
The standard of care for acute ischemic stroke evaluation in the extended time window (6-24 hours) follows a strict sequence to minimize time to treatment while ensuring safety and efficacy. Hemorrhage must first be excluded (non-contrast CT), followed by identifying the vascular target (CTA), and then confirming salvageable brain tissue (CT perfusion). MRI is reserved for delayed, definitive follow-up.

Adım Adım Çözüm

1
Exclude intracranial hemorrhage.
Non-contrast CT of the head is ordered first.
Before any antithrombotic or invasive endovascular therapy can be considered, acute hemorrhage must be definitively excluded. This is the fastest and most widely available initial triage test.
2
Identify a therapeutic vascular target.
CTA of the head and neck is ordered second.
Once hemorrhage is ruled out, imaging the cerebral vasculature is required to confirm a large vessel occlusion (LVO) amenable to mechanical thrombectomy.
3
Assess tissue viability for extended-window intervention.
CT perfusion imaging is ordered third.
Because the patient's last known well time was 10 hours ago (beyond the standard 6-hour window), perfusion imaging is necessary to identify a mismatch between the infarct core and the salvageable ischemic penumbra, per DEFUSE-3 and DAWN criteria.
4
Confirm final infarct volume and assess for complications.
MRI of the brain is ordered last.
In the subacute phase (typically 24-48 hours later), MRI provides the highest spatial resolution to determine the exact extent of infarction and rule out secondary hemorrhagic transformation.

Anahtar Kavram

In patients presenting with acute ischemic stroke in the extended time window (6-24 hours), the imaging sequence progresses from excluding hemorrhage (non-contrast CT), to localizing the vascular occlusion (CTA), to assessing tissue viability (CT perfusion), and finally to subacute definitive assessment (MRI).
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Ordering Imaging Studies

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