What is the role of CT scanning in the emergent workup for posterior cerebral artery (PCA) stroke?

Updated: Jul 30, 2018
  • Author: Erek K Helseth, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

All patients with suspected stroke should undergo emergent neuroimaging with CT scanning or MRI. An unenhanced head CT scan is usually performed, as this test is widely available, can be rapidly obtained, and is sensitive in identifying intracranial hemorrhage. (See the images below.)

Unenhanced head computed tomography (CT) scan demo Unenhanced head computed tomography (CT) scan demonstrating a subacute L posterior cerebral artery (PCA) infarct.
Unenhanced head computed tomography (CT) scan demo Unenhanced head computed tomography (CT) scan demonstrating hemorrhagic conversion of an ischemic stroke, approximately 72 hours after symptom onset.

An emergent CT or MRI scan is required prior to considering acute stroke therapies, including thrombolysis. CT scanning aids in the following:

  • Identifying hemorrhage

  • Identifying strokes that may be less acute than reported by patients - Ie, the presence of hypodensity suggests a more subacute than hyperacute process

  • Identifying hyperdense vessels

  • Excluding alternate diagnoses that may masquerade as stroke - Ie, neoplasm or other masses

CT scanning is less sensitive for lesions in the infratentorial region than the supratentorial region due to bony signal artifact and decreased tissue detail.


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