Altered hemodynamics and regional cerebral blood flow in patients with hemodynamically significant stenoses
Anne C Roc1, Jiongjiong Wang, Beau M Ances
1Center for Functional Neuroimaging, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
Insights
Patients with arterial stenoses show altered blood oxygen level-dependent (BOLD) responses during motor tasks. This suggests BOLD imaging can detect hemodynamic changes in cerebrovascular disease.
Area of Science:
- Neuroimaging
- Cerebrovascular Physiology
- Magnetic Resonance Imaging
Background:
- Blood oxygen level-dependent (BOLD) contrast is sensitive to cerebral blood flow (CBF) changes.
- Cerebrovascular disease can significantly alter CBF.
- Assessing BOLD response dynamics in patients with arterial stenoses is crucial.
Purpose of the Study:
- To evaluate the temporal dynamics and magnitude of the BOLD response in patients with major arterial stenoses.
- To compare BOLD responses between patients with anterior circulation stenoses and healthy controls.
- To determine if BOLD imaging can detect hemodynamic alterations in cerebrovascular disease.
Main Methods:
- Seven patients with significant anterior circulation stenoses and seven healthy controls were studied.
- Continuous arterial spin-labeled perfusion MRI was used to measure resting CBF.
- A visuomotor task (handball squeeze) was employed to elicit and measure the BOLD response.
Main Results:
- Patients exhibited reduced baseline CBF in specific brain regions.
- A prolonged BOLD response and an enhanced initial dip were observed in patients' motor cortices.
- No significant differences in motor task performance were found between groups.
Conclusions:
- Patients with arterial stenoses display a distinct BOLD hemodynamic response pattern, including initial deoxygenation followed by delayed hyperperfusion.
- These BOLD alterations occur even when resting CBF is not in the ischemic range.
- A simple visuomotor BOLD activation paradigm effectively reflects hemodynamic changes in patients with significant arterial stenoses.
Background And Purpose:
Blood oxygen level-dependent (BOLD) contrast largely depends on changes in cerebral blood flow (CBF). Because cerebrovascular disease may result in altered CBF, we assessed the temporal dynamics and magnitude of the BOLD response in patients with major arterial stenoses.
Methods:
Seven patients with hemodynamically significant stenoses affecting the anterior circulation (primarily left internal carotid and middle cerebral arteries) were compared with 7 neurologically healthy subjects. Continuous arterial spin-labeled perfusion MRI was used to measure resting CBF globally and within various vascular distributions. The BOLD response was acquired during a visually guided bilateral handball squeeze task while motor performance was recorded by a pressure transducer.
Results:
Baseline CBF was reduced in bilateral middle cerebral artery and left anterior cerebral artery territories in patients. A prolonged BOLD hemodynamic response was observed in patients in bilateral primary motor cortices but not visual cortex. Patients also exhibited a larger early negative BOLD response, or "initial dip," in left primary motor cortex. There were no differences in motor performance between groups, suggesting behavioral differences were not primarily responsible for the characteristics of the BOLD response.
Conclusions:
An initial deoxygenation followed by a delayed hyperemic BOLD response was observed in patients, although resting flow values were not within an ischemic range. A simple visuomotor BOLD activation paradigm can reflect alterations in the hemodynamic response in patients with hemodynamically significant stenoses.
More Related Videos
12:15Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion
Published on: February 17, 2013
10:41Analysis of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage with High Frequency Transcranial Duplex Ultrasound
Published on: June 3, 2021
