Simultaneous Real-time Imaging of Neurofluid and Neurovascular Dynamics Using Ultrafast Flow-weighted Echo-Planar...

Area of Science:

• Neuroimaging
• Fluid dynamics
• Biomedical engineering

Background:

• Cerebrospinal fluid (CSF) circulation is vital and linked to cerebral blood flow, influenced by cardiac and respiratory cycles.
• Disruptions in CSF flow dynamics are associated with neurological disorders.
• Current methods like phase contrast MRI (PC-MRI) have limitations in temporal resolution and sensitivity to non-cardiac fluctuations.

Purpose of the Study:

• To introduce and validate a novel imaging technique, SURF-EPI, for simultaneous real-time assessment of CSF and neurovascular flow.
• To overcome the temporal resolution limitations of conventional PC-MRI for dynamic flow analysis.
• To characterize CSF flow dynamics and their relationship with vascular flow in the cervical spine.

Main Methods:

• Development and application of self-gated ultrafast real-time flow-weighted echo-planar imaging (SURF-EPI) at the C2-C3 spinal level.
• Acquisition of simultaneous CSF, arterial inflow, and venous outflow data at high temporal resolution (21.7 Hz).
• Utilized intrinsic arterial signal fluctuations for cardiac-resolved CSF dynamics reconstruction without external gating.

Main Results:

• SURF-EPI enabled real-time imaging of cervical CSF and major vessel blood flow.
• Frequency-domain analysis revealed distinct spectral signatures for CSF flow versus neurovascular flow.
• Beat-to-beat analysis demonstrated significant cycle-to-cycle variability in CSF flow, unobserved in gated methods.

Conclusions:

• SURF-EPI is a rapid, complementary imaging framework to PC-MRI for real-time neurofluid dynamics.
• The technique provides integrated time- and frequency-domain characterization of CSF and neurovascular flow.
• SURF-EPI offers enhanced insights into CSF flow dynamics, including beat-to-beat variability, crucial for understanding neurological health.