Related Experiment Video
Updated: Jan 31, 2026

Author Spotlight: Innovative Technique for Coronary Angiography in Marginal Donors
Published on: July 12, 2024
Circle of Willis: evaluation with spiral CT angiography, MR angiography, and conventional angiography
D A Katz1, M P Marks, S A Napel
1Department of Radiology, Stanford University Medical Center, CA 94305-5105, USA.
Purpose:
To evaluate the use of spiral computed tomographic (CT) angiography in the analysis of the arteries of the circle of Willis and compare these results with magnetic resonance (MR) angiography and conventional angiography.
Materials And Methods:
The results in 17 patients who underwent examination were prospectively studied in a blinded fashion. The presence or absence of the arteries of the circle of Willis was determined by using maximum intensity projection reconstructions from CT angiography and MR angiography. These results were compared with results from conventional angiography.
Results:
Similar sensitivities were determined for CT angiography (88.5%) and MR angiography (85.5%); however, MR angiography was found to differ significantly (P = .005) from conventional angiography. No significant differences (P > .05) were found between the two modalities and conventional angiography in the detection of the anterior, middle, or posterior cerebral arteries or the anterior communicating artery.
Conclusion:
Spiral CT angiography is highly sensitive in the detection of arterial anatomy in the circle of Willis and is a reliable alternative to MR angiography.
More Related Videos
Related Concept Videos
Circles
Sign Convention
The normal force acts perpendicular to the beam's cross-section and can...
Mohr's Circle for Moments of Inertia: Problem Solving
Consider a rectangular beam. The moments of inertia of the beam about the x and y axis are 2.5(107) mm4 and 7.5(107) mm4, respectively. The product of inertia is 1.5(107) mm4. Determine the principal moments of inertia and the orientation of the major and...
Enolate Mechanism Conventions
Mohr's Circle for Moments of Inertia
Mohr's Circle for Plane Stress
Consider a set of Cartesian coordinates. The horizontal and vertical axes correspond to normal stress (σ) and shearing stress (τ), respectively. Two points, points A and B, are defined by the normal and shear...

