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

Neurofluid dynamics are crucial for maintaining brain homeostasis and facilitating the clearance of brain metabolites through the coupling of arterial and venous blood with cerebrospinal fluid (CSF). Two-dimensional phase contrast (PC) magnetic resonance imaging (MRI) is frequently used to study neurofluids; however, separate examinations are typically required for assessing blood and CSF flow, which can confound analyses due to asynchronous physiological measurements. To enable simultaneous assessment of neurofluid dynamics, we describe and evaluate a 2D PC MRI approach in human participant experiments. An interleaved multi-point velocity encoding scheme was integrated into a 2D golden angle spiral PC MRI scan to facilitate synchronous characterization of neurofluids. Two multi-point schemes, including interleaved dual-venc (DV) and triple-venc (MV) scans, were evaluated and compared with standard asynchronous single-venc (SV) scans. Data and repeated scans were collected on a clinical 3.0T scanner at the level of the C1/C2 vertebrae in 10 human participants. From cardiac-resolved images, the relationship between net blood flow and CSF flow pulsatile volume change was characterized using regression modeling. Temporal lags between cardiac-driven arterial blood (vertebral arteries (VAs) and internal carotid arteries (ICAs)) and spinal canal (SC) CSF were estimated with cross-correlation. SV, DV, and MV flow mean, range, and volume changes were studied and compared using linear mixed effect models, intraclass correlation coefficients, Bland-Altman, and Pearson correlations. A strong relationship was measured between net blood flow and CSF flow pulsatile volume change from SV (R