CTA CIRCLE OF WILLIS
(updated 09/12/2025, last reviewed 09/12/2025)
INDICATION: Aneurysm, stenosis, occlusion, stroke, thromoembolism, dissection, vasculitis/vasculopathy, vascular infection, preoperative planning, vasospasm, vascular tumor/malformation.
SERIES
1) Noncontrast head CT
2) CTA COW
- 1mm axial CTA
- 2mm coronal CTA
- 2mm sagittal CTA
- 3D reformats
- Axial MIP CTA HEAD (20 mm)
- Coronal MIP CTA HEAD (20 mm)
TECHNICAL PARAMETERS
POSITIONING/MODE: supine / helical
POSITIONING/MODE: supine / helical
SINGLE COLLIMATION WIDTH: 0.625 mm
SLICE THICKNESS: 1 mm axial
KERNAL: soft tissue
SFOV: <30 cm
COVERAGE: Foramen magnum -> vertex
ACQUISITION: caudocranial
IV CONTRAST: yes
INJECTION RATE: 4 mL/sec
SCAN DELAY; bolus tracking @ aortic arch (~20 sec)
POSTPROCESSING: 2 mm coronal, 2 mm sagittal, 3D reformats, Axial and Coronal MIPs