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Updated: Aug 12, 2026
Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery
Published on: September 5, 2018
Qualitative phase contrast MRA in the normal and abnormal circle of Willis
Insights
Three-dimensional phase contrast MR angiography reveals normal and altered blood flow patterns in the circle of Willis. This technique effectively visualizes hemodynamics in both healthy individuals and those with cerebrovascular occlusive disease.
Area of Science:
- Medical Imaging
- Neuroscience
- Vascular Biology
Background:
- The circle of Willis is a critical arterial network at the base of the brain.
- Understanding blood flow dynamics within the circle of Willis is essential for diagnosing cerebrovascular diseases.
- Phase contrast magnetic resonance angiography (MRA) offers non-invasive visualization of blood flow.
Purpose of the Study:
- To assess blood flow direction in the circle of Willis using high-resolution 3D phase contrast MRA.
- To characterize normal hemodynamic patterns in the circle of Willis.
- To identify alterations in blood flow associated with occlusive cerebrovascular disease.
Main Methods:
- Utilized 3D phase contrast MRA in 50 healthy subjects and 15 patients with occlusive disease.
- Acquired high spatial resolution angiographic data.
- Analyzed blood flow direction in key arteries of the circle of Willis, including posterior communicating and anterior cerebral arteries.
Main Results:
- In healthy subjects, 78% showed detectable flow in posterior communicating arteries, predominantly anterior-to-posterior (92%).
- Anterior cerebral artery A1 segments demonstrated expected flow from carotid to A2 segments in all normal subjects.
- Patients with carotid occlusion exhibited altered flow, including reversed flow in ipsilateral posterior communicating arteries and sometimes A1 segments.
Conclusions:
- 3D phase contrast MRA is a valuable tool for evaluating circle of Willis hemodynamics.
- The technique accurately depicts normal blood flow patterns.
- It effectively identifies abnormal flow associated with cerebrovascular occlusive conditions.
Purpose:
To determine the direction of blood flow in the circle of Willis using a 3-D phase contrast MR angiographic (MRA) technique with high spatial resolution.
Subjects:
Fifty healthy subjects and 15 patients with occlusive disease were studied using 3-D phase contrast MRA.
Results:
In the 50 normal subjects, 39 (78%) had detectable flow in one or both posterior communicating arteries. In 24 (48%) of these subjects, flow was detected in both posterior communicating arteries, whereas unilateral flow was detected in 15 (30%). In 36 (92%) of the 39 normal subjects, flow in the posterior communicating artery was from anterior to posterior with only 3 (8%) showing reverse flow from posterior to anterior. The A1 segment of both anterior cerebral arteries was identified in 100% of normal subjects with flow in the expected direction from carotid to the A2 segment. In patients with carotid occlusion, the pattern of flow in the circle of Willis was altered with reversed flow in the ipsilateral posterior communicating artery and sometimes in the ipsilateral A1 segment. An ipsilateral posterior communicating artery was present in 10 of 17 occluded carotid arteries, all showing reversed flow.
Conclusion:
3-D phase contrast MRA provides useful information about the hemodynamics of normal and abnormal blood flow in the circle of Willis.
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