CT Imaging in Acute Stroke Evaluation

Initial Imaging: Noncontrast CT Head

The American College of Radiology recommends noncontrast CT head as the essential initial imaging study to rule out stroke, specifically to exclude intracranial hemorrhage and identify early ischemic changes before initiating treatment 1, 2, 3, 4, 5
Noncontrast CT head excludes intracranial hemorrhage, which is essential before administering IV thrombolytic therapy or initiating endovascular thrombectomy, according to the American College of Radiology guidelines 1, 4, 5
Noncontrast CT head identifies early ischemic changes that help estimate the extent of irreversible tissue damage and guide therapeutic decisions using scoring systems like ASPECTS, as recommended by the American College of Radiology 1, 4
The American College of Radiology states that noncontrast CT head rules out stroke mimics and other potential etiologies for neurological symptoms 1, 6

The American College of Radiology guidelines explicitly state that CT head with IV contrast alone has no role in acute stroke evaluation 1, 2, 3, 4, 5, 7
The American College of Radiology recommends that contrast administration may actually obscure early complications such as hemorrhage, making it counterproductive in acute stroke imaging 7

The American College of Radiology recommends that CTA head with IV contrast should be added immediately if large vessel occlusion is suspected 1, 2, 4, 5
CTA head is the most rapid means of detecting intracranial large vessel occlusions with high sensitivity and specificity, according to the American College of Radiology 1, 4, 5
The American College of Radiology states that CTA is supported by multiple randomized controlled trials as the preferred method for LVO detection due to the time-sensitive nature of stroke care 1, 4, 5

The American College of Radiology recommends that within the first 6 hours of symptom onset, CT perfusion is usually not necessary as an initial examination 1, 2
For presentations 6-24 hours after onset, CT perfusion with IV contrast may be required to determine EVT eligibility in anterior circulation strokes with confirmed LVO, according to the American College of Radiology 1, 2, 4, 5

The American College of Radiology recommends starting with noncontrast CT head in all suspected stroke patients 1, 4, 6
If hemorrhage is excluded and LVO is suspected, immediately proceed to CTA head (and neck if appropriate), as recommended by the American College of Radiology 1, 4, 5
For presentations beyond 6 hours with confirmed LVO, consider adding CT perfusion to determine EVT eligibility, according to the American College of Radiology 1, 2, 4