Perfusion information extracted from resting state functional magnetic resonance imaging

Area of Science:

• Neuroimaging
• Physiology
• Medical Physics

Background:

• Functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) contrast indirectly measures neuronal activity.
• BOLD signals are affected by non-neuronal physiological fluctuations.
• Previous resting-state (RS) fMRI studies identified systemic low frequency oscillations (sLFO) in BOLD signals.

Purpose of the Study:

• To test the hypothesis that dynamic patterns of sLFO in RS fMRI represent cerebral blood flow.
• To compare sLFO dynamics with direct blood flow measurements.

Main Methods:

• Performed Dynamic Susceptibility Contrast (DSC) MRI scans (bolus tracking) on eight healthy subjects.
• Compared dynamic patterns of sLFO from RS fMRI with DSC-derived blood flow.
• Utilized visual and quantitative analysis for comparison.

Main Results:

• The flow patterns of sLFO derived from RS fMRI largely correspond to blood flow measured by DSC.
• Minor discrepancies are attributed to differing sensitivities of the methods to various vessel types.

Conclusions:

• The flow of sLFO in RS fMRI, visualized via time-delay mapping, accurately represents blood flow in brain capillaries and veins.
• This provides a novel method for assessing cerebral hemodynamics using non-invasive RS fMRI.