CT angiography of the head

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Author: Mikael Häggström [notes 1]

Planning

Alternative investigations

Magnetic resonance angiography of the head is indicated in:

  • Less emergent situations, since it is generally less readily available.
  • Contraindications to intravenous contrast, since it can visualize cerebral vessels without it.

Settings

  • Preceding non-contrast CT of the head. If this has been done recently, generally repeat if a few hours has passed in an emergent setting.
  • Slice thickness: Aneurysms are more readily visualized by thick slices such as 15mm, but thin slices such as 1.2 mm still need to be observed if there may be a focal occlusion or stenosis.
  • Range and timing depends on main suspicions:
Targets Range Bolus tracking delay
(ROI in aortic arch)
Stroke and/or carotid dissection Aortic arch to vertex of skull 0-5 seconds[1]
Aneurysm or arteriovenous malformation Skull base to vertex 2-7 seconds[1]
Sinus thrombosis Skull base to vertex 12 - 17 seconds[1]

Basic screening

In addition to a Basic screening of a head CT, look for:

  • Discrepancies between the left and right side regarding contrast filling of arteries. Direct comparisons can be made between stems of major arteries, while for lesser branches it is enough to compare the overall artery coverage in cerebral and cerebellar volumes.
  • Obvious aneurysms

Report

  • Significant anatomical variants, such as left-right discrepancies circle of Willis and its supplying arteries.

Example report: Normal contrast filling of the major intracranial vessels.

See also: Head CT report

Diseases

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.

References