Blood flow in the carotid arteries: quantification by using phase-sensitive MR imaging

Area of Science:

• Medical Imaging
• Cardiovascular Science
• Neurology

Background:

• Carotid artery blood flow quantification is crucial for diagnosing cerebrovascular disease.
• Noninvasive methods are needed to assess carotid artery hemodynamics.
• Magnetic resonance (MR) imaging offers potential for detailed vascular assessment.

Purpose of the Study:

• To evaluate the feasibility of MR phase-sensitive imaging for quantifying blood flow in carotid arteries.
• To assess the accuracy of MR phase-sensitive imaging in normal volunteers and patients with carotid artery or cerebrovascular disease.

Main Methods:

• MR phase-sensitive imaging was employed, sensitizing the MR signal phase to blood flow velocity.
• Flow velocities and volumes were measured in common, internal, and external carotid arteries using transverse planes.
• Flow curves were generated, and measurements were validated using flow phantoms.

Main Results:

• MR measurements in normal volunteers showed total common carotid artery flow between 250-580 ml/min.
• Significantly reduced flow (approx. 50% below normal) was detected in a patient with severe internal carotid artery occlusion.
• Abnormally high flow (approx. 1 liter/min) was observed in a patient with an intracranial arteriovenous malformation.

Conclusions:

• MR phase-sensitive imaging is a feasible tool for noninvasively quantifying carotid blood flow.
• The technique demonstrated accuracy in normal subjects and sensitivity to hemodynamic changes in disease states.
• Preliminary findings support the clinical utility of MR phase mapping for carotid blood flow assessment.