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Updated: Jul 6, 2025
Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery
Published on: September 5, 2018
Cerebral Blood Flow Patterns in Patients With Low-Flow Carotid Artery Stenosis, a 4D-PCMRI Assessment
Laleh Zarrinkoob1, Sanne Myrnäs1, Anders Wåhlin2,3,4
1Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine Unit, Umeå University, Umeå, Sweden.
Insights
Reduced internal carotid artery blood flow (ICA-BFR) significantly impacts cerebral hemodynamics, causing asymmetrical blood flow distribution in the brain. Collateral circulation is insufficient to compensate for decreased ICA-BFR in patients with carotid stenosis.
Area of Science:
- Cerebrovascular Medicine
- Medical Imaging
- Neurology
Background:
- Compromised cerebral blood flow (CBF) is a risk factor for ischemic events in symptomatic carotid artery disease.
- Limited understanding exists regarding the impact of reduced internal carotid artery blood flow rate (ICA-BFR) on cerebral hemodynamics.
Purpose of the Study:
- To investigate the relationship between reduced ICA-BFR and blood flow rate (BFR) in cerebral arteries.
- To assess cerebral hemodynamic changes in patients with symptomatic carotid stenosis and reduced ICA-BFR.
Main Methods:
- Prospective study involving 38 patients (age 72 ± 6 years) with symptomatic carotid stenosis (≥50%).
- 3-Tesla, four-dimensional phase-contrast magnetic resonance imaging (4D-PCMRI) was used to measure cerebral BFR.
- Patients were grouped into reduced ICA-flow (<160 mL/min) and preserved ICA-flow (≥160 mL/min) subgroups; statistical analysis (t-tests) compared groups and hemispheres (P < 0.05 significance).
Main Results:
- No significant difference in stenosis degree between reduced (80%) and preserved (72%) ICA-flow groups (P=0.09).
- Reduced ICA-flow group showed significantly decreased ipsilateral middle cerebral artery and anterior cerebral artery (A1) BFR, and increased contralateral A1 BFR.
- Retrograde BFR observed in the posterior communicating and ophthalmic arteries; significant BFR laterality present in all paired arteries in the reduced ICA-flow group.
Conclusions:
- 4D-PCMRI reveals compromised cerebral BFR due to carotid stenosis, undetectable by stenosis degree alone.
- In reduced ICA-flow patients, collateral circulation is insufficient to maintain symmetrical BFR distribution between hemispheres.
Background:
Compromised cerebral blood flow can contribute to future ischemic events in patients with symptomatic carotid artery disease. However, there is limited knowledge of the effects on cerebral hemodynamics resulting from a reduced internal carotid artery (ICA) blood flow rate (BFR).
Purpose:
Investigate how reduced ICA-BFR, relates to BFR in the cerebral arteries.
Study Type:
Prospective.
Subjects:
Thirty-eight patients, age 72 ± 6 years (11 female).
Field Strength/Sequence:
3-Tesla, four-dimensional phase-contrast magnetic resonance imaging (4D-PCMRI).
Assessment:
Patients with ischemic stroke or transient ischemic attack were evaluated regarding the degree of stenosis. 4D-PCMRI was used to measure cerebral BFR in 38 patients with symptomatic carotid stenosis (≥50%). BFR in the cerebral arteries was assessed in two subgroups based on symptomatic ICA-BFR: reduced ICA-flow (<160 mL/minutes) and preserved ICA-flow (≥160 mL/minutes). BFR laterality was defined as a difference in the paired ipsilateral-contralateral arteries.
Statistical Tests:
Patients were grouped based on ICA-BFR (reduced vs. preserved). Statistical tests (independent sample t-test/paired t-test) were used to compare groups and hemispheres. Significance was determined at P < 0.05.
Results:
The degree of stenosis was not significantly different, 80% (95% confidence interval [CI] = 73%-87%) in the reduced ICA-flow vs. 72% (CI = 66%-76%) in the preserved ICA-flow; P = 0.09. In the reduced ICA-flow group, a significantly reduced BFR was found in the ipsilateral middle cerebral artery and anterior cerebral artery (A1), while significantly increased in the contralateral A1. Retrograde BFR was found in the posterior communicating artery and ophthalmic artery. Significant BFR laterality was present in all paired arteries in the reduced ICA-flow group, contrasting the preserved ICA-flow group (P = 0.14-0.93).
Data Conclusions:
4D-PCMRI revealed compromised cerebral BFR due to carotid stenosis, not possible to detect by solely analyzing the degree of stenosis. In patients with reduced ICA-flow, collaterals were not sufficient to maintain symmetrical BFR distribution to the two hemispheres.
Evidence Level:
2 TECHNICAL EFFICACY: Stage 3.
