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Magnetic resonance imaging of flow dynamics in the circle of Willis
R R Edelman1, H P Mattle, G V O'Reilly
1Department of Radiology, Beth Israel Hospital, Harvard Medical School, Boston, MA 02215.
Insights
Magnetic resonance angiography noninvasively images intracranial arteries, revealing blood flow dynamics in the circle of Willis. This technique accurately depicts blood supply and collateral flow in cerebrovascular disease patients.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Cerebrovascular disease affects blood flow in the brain's major arteries.
- Understanding blood flow dynamics in the circle of Willis is crucial for diagnosis.
- Noninvasive imaging methods are needed to assess intracranial arterial supply.
Purpose of the Study:
- To evaluate the utility of magnetic resonance angiography (MRA) for studying blood flow dynamics in the circle of Willis.
- To assess the ability of MRA to determine blood flow direction and vascular supply origins.
- To compare MRA findings with transcranial Doppler sonography and conventional angiography.
Main Methods:
- MRA, utilizing 2D or 3D gradient-echo acquisitions, was performed on nine patients with cerebrovascular disease and two healthy volunteers.
- Selective presaturation of individual vessels was employed to trace blood flow direction and supply.
- Results were cross-referenced with transcranial Doppler sonography and conventional angiography.
Main Results:
- MRA successfully demonstrated blood flow direction within the circle of Willis.
- The technique identified the presence or absence of collateral blood flow.
- MRA accurately depicted blood supply to pericallosal arteries and identified fetal posterior circulation patterns.
Conclusions:
- Magnetic resonance angiography is a noninvasive and effective method for imaging the blood supply of major intracranial arteries.
- MRA provides valuable insights into blood flow dynamics and collateral circulation in the circle of Willis.
- This technique aids in the assessment of cerebrovascular disease.
Abstract:
Magnetic resonance angiography was applied to the study of blood flow dynamics in the circle of Willis in nine patients with cerebrovascular disease and two normal volunteers. In conjunction with two-dimensional or three-dimensional gradient-echo acquisitions, selective presaturation of individual vessels was used to determine the direction of blood flow and the origin of the vascular supply. Presaturation causes signal loss within the territory supplied by the presaturated artery, without affecting vessels not crossing the presaturation slab. The results were correlated with those from transcranial Doppler sonography and conventional angiography. Magnetic resonance angiography was able to demonstrate the direction of blood flow, the presence or absence of collateral blood flow, and the blood supply to the pericallosal arteries, as well as the presence of a fetal posterior circulation. Magnetic resonance angiography is a noninvasive means for imaging the blood supply of the major intracranial arteries.