Decreased Craniocervical CSF Flow in Patients with Normal Pressure Hydrocephalus: A Pilot Study

Measurement of CSF/blood flow and spinal canal width. A, Craniospinal blood and CSF flow (milliliter/minute) during the cardiac cycle across time (millisecond). The upper panel shows the blood flow. During each systole, arterial blood (red) flows into the cranium and venous blood flows in a cardiac direction; outflow is too slow to compensate the resulting increase in intracranial pressure. The lower panel shows the resulting fast CSF outflow (green) from the brain to the spinal CSF spaces to buffer pressure peaks. B, VENC phase-contrast MR images of blood and CSF. The upper panel demonstrates the blood flow through the internal carotid arteries (arrows) and vertebral arteries (arrowheads), and the internal jugular veins are represented by the oval white spots (not marked). The lower panel shows the flow of CSF (black dashed arrow) from the cranium to the spinal canal. Upward flow is black, while downward flow is white. C, Measurement (double-sided arrow) of the maximal diameter of the spinal canal in a midsagittal MPRAGE image at the level of the intervertebral space between the second and third upper cervical vertebrae (Ø_C2/C3) is shown.