Fig 2.

Axial MR images of oscillatory flow velocity in 7 locations in the spine (C3, T1, T3, T6, T8, T10, T12) at systole, reversal of flow, and diastole for subject 1 (A), plot of CSF flow rate over 3 cardiac cycles at the 7 locations, using as a reference time the beginning of systole at the C3 level (dashed line) (B), and plot of the variation of the stroke volume of the oscillations of the CSF over the length of the spinal canal (C). During the cardiac cycle, systolic flow (shaded red) has greater velocity and shorter duration than diastolic flow (shaded blue). Oscillatory CSF flow rates diminish in the craniocaudal direction along the spine with the stroke volume diminishing to zero at the sacral end of the spine. CSF flow oscillatory velocities are greater in the anterior (s = 0) and anterolateral regions of the cervical subarachnoid space (s = 0.25 and s = 0.75) than in the posterior subarachnoid space (s = 0.5).