Table 1.
Anatomic (T2-VISTA) and CSF flow (phase-contrast MRI) scan protocol parameters used for imaging cynomolgus monkeys.
Fig 1.
Manual segmentation of the spinal subarachnoid space using a T2-weighted MR image for a cynomolgus monkey analyzed in this study.
(A) Visualization of SAS area manually selected around the spinal cord at multiple axial levels. (B) Mid-sagittal high-resolution T2-weighted MRI. (C) Sagittal visualization of segmented SAS around the spinal cord. (D) 3D visualization of entire SAS geometry. The same methods were applied to all MR images obtained for all NHPs.
Fig 2.
Axial PC-MRI and CSF velocity profiles at corresponding vertebral levels for a cynomolgus monkey in this study.
(A) PC-MRI axial cross-sections for a given case at each respective vertebral level. (B) T2-weighted MR image of a cynomolgus monkey in the study with corresponding PC-MRI axial locations and slice orientation (solid green lines) at FM, C2-C3, C5-C6, T4-T5, T11-T12, and L3-L4. (C) 3D visualization of peak systolic CSF velocity profiles based on in vivo PC-MRI measurements at each vertebral level.
Table 2.
Reference chart for vertebral disk location with respect to axial distance from the foramen magnum in cynomolgus monkeys.
Table 3.
Summary of geometric and hydrodynamic results.
Mean values correspond to the average along the entire spine for all 16 NHPs (except for total surface area, volume, and PWV). Local maximum and minimum values are computed based the average for all 16 NHPs.
Fig 3.
Geometric parameters distribution computed along the spine for cynomolgus monkeys.
(A) Area of dura, (B) Area of spinal cord, (C) Area of subarachnoid space, (D) Perimeter of dura, (E) Perimeter of spinal cord, (F) Perimeter of subarachnoid space. Mean value for all 16 NHPs corresponds to the solid line. Dotted lines correspond to ± 1 standard deviation for all 16 NHPs analyzed.
Fig 4.
CSF flow waveforms for all 16 cases measured by PC-MRI at six axial locations along the spine.
Error bars correspond to ± 1 standard deviation of flow rates obtained for all 16 NHPs. Note: negative, or peak systolic, CSF flow is in the caudal direction.
Fig 5.
Mean CSF flow waveforms and Spatial-temporal distribution of CSF flow rate.
(A) Mean CSF flow waveforms for all 16 cases measured by PC-MRI at six axial locations along the spine. Note: negative, or peak systolic, CSF flow is in the caudal direction. (B) Spatial-temporal distribution of the interpolated CSF flow rate along the spine. Dotted line indicates peak CSF flow rate at each axial level used to compute CSF pulse wave velocity (PWV).
Fig 6.
Hydrodynamic parameter distribution computed along the spine for cynomolgus monkeys.
(A) Reynolds number, Re, (B) Flow rate amplitude, Qa, (C) Stroke Volume, SV, (D) left axis, Hydraulic diameter, Dh, right axis, Womersley number, α, (E) mean peak systolic, , and diastolic,
, CSF velocity. Mean value for all 16 NHPs corresponds to the solid line. Dotted lines correspond to ± 1 standard deviation for all 16 NHPs analyzed.
Fig 7.
Scatter plots of geometric parameters.
(A) Area of dura, (B) Area of spinal cord, (C) Area of subarachnoid space, (D) Perimeter of dura, (E) Perimeter of spinal cord, (F) Perimeter of subarachnoid space. Dot color represents distance from the FM (blue is near the FM and red is near the SAS termination).
Fig 8.
Scatter plots of hydrodynamic parameter distribution computed along the spine.
(A) Reynolds number, Re, (B) flow rate amplitude, Qa, (C) stroke volume, SV, (D) hydraulic diameter, Dh, (E) Womersley number, α, and, (F) mean peak systolic, , and diastolic,
, CSF velocity. Dot color represents distance from the FM (blue is near the FM and red is near the SAS termination).