Vascular compliance in normal pressure hydrocephalus.

Area of Science:

• Neurology
• Vascular Biology
• Medical Imaging

Background:

• Normal pressure hydrocephalus (NPH) is associated with impaired cerebrospinal fluid (CSF) resorption and reversible cerebral ischemia.
• Altered venous compliance in the superior sagittal sinus (SSS) territory is hypothesized to play a role in NPH and cerebral ischemia.

Purpose of the Study:

• To investigate the association between reduced venous compliance in the SSS territory and NPH.
• To compare vascular compliance in patients with NPH, cerebral ischemia/atrophy, and healthy controls.

Main Methods:

• Prospective study of 27 patients without hydrocephalus, subdivided by MR findings (normal vs. ischemia/atrophy).
• MR flow quantification used to measure vascular compliance (NSPV, AVD) in the SSS and straight sinus territory.
• Ten NPH patients underwent pre- and post-CSF drainage MR studies.

Main Results:

• Patients with ischemia/atrophy exhibited significantly higher vascular compliance (mean NSPV in SSS: 417 µL) than healthy subjects (274 µL).
• NPH patients showed lower SSS compliance (mean NSPV: 212 µL, mean AVD: 42 ms) compared to healthy subjects (274 µL, 89 ms).
• Post-intervention, NPH patients' compliance approached that of the ischemia/atrophy group.

Conclusions:

• Vascular compliance significantly differs between healthy subjects, patients with ischemia/atrophy, and NPH patients.
• Findings suggest altered venous compliance is a key factor in the pathophysiology of NPH and cerebral ischemia.