Simultaneous and synchronous characterization of blood and CSF flow dynamics using multiple Venc PC MRI

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Neurofluid dynamics, involving blood and cerebrospinal fluid (CSF), are vital for brain homeostasis and metabolite clearance.
• Current methods using 2D phase contrast (PC) MRI for neurofluid studies require separate, asynchronous measurements of blood and CSF flow, limiting analysis.
• Simultaneous assessment of these flows is needed to accurately characterize their dynamic coupling.

Purpose of the Study:

• To develop and evaluate a novel 2D PC MRI technique for simultaneous quantification of cranio-spinal arterial, venous, and CSF flow.
• To compare the performance and repeatability of simultaneous multi-point velocity encoding schemes (dual-venc and triple-venc) against standard single-venc scans.
• To investigate the relationship and temporal lags between blood flow and CSF flow using the new simultaneous imaging approach.

Main Methods:

• A 2D golden angle spiral PC MRI sequence was modified with an interleaved multi-point velocity encoding scheme (dual-venc and triple-venc) for synchronous neurofluid assessment.
• Data were acquired on 10 human participants at the C1/C2 vertebral level using a 3.0T clinical scanner.
• Regression modeling, cross-correlation, linear mixed effect models, intraclass correlation coefficients, Bland-Altman analysis, and Pearson correlations were used to analyze flow dynamics and repeatability.

Main Results:

• A strong correlation was found between net blood flow and CSF flow pulsatile volume changes across all tested MRI schemes (R² up to 0.78, P < 0.001).
• Statistically significant longer temporal lags were observed between spinal canal CSF and vertebral artery flow compared to internal carotid artery flow.
• Simultaneous dual-venc and triple-venc MRI scans demonstrated higher repeatability than standard single-venc scans, although triple-venc tended to underestimate CSF flow markers.

Conclusions:

• The developed interleaved multi-point 2D PC MRI method enables simultaneous imaging of cranio-spinal arterial, venous, and CSF flow.
• This synchronous assessment improves the evaluation of neurofluid coupling compared to traditional asynchronous methods.
• The findings highlight the potential of simultaneous multi-point velocity encoding MRI for advancing the study of neurofluid dynamics and brain health.