Imaging cerebrospinal fluid dynamics in idiopathic normal pressure hydrocephalus
Year: 2018
Type: dissertation
Study design: Observational Study
Abstract: In this thesis, magnetic resonance imaging (MRI) is used to explore short- and long term characteristics of cerebrospinal fluid (CSF) flow in patients with idiopathic normal pressure hydrocephalus (iNPH). Typical symptoms like gait disorder, urinary incontinence and dementia may be improved with surgical shunting, and responders to treatment can be identified by monitoring of intracranial pressure (ICP) pulsatility, but with a small risk of complications. In search for non-invasive diagnostic alternatives, radiological markers of CSF flow pulsatility (i.e. the aqueductal stroke volume and the peak-to-peak pulse pressure gradient at the craniocervical junction) derived from phase-contrast MRI (PC-MRI) were compared with over-night ICP monitoring. In this, no signs of association with ICP parameters or clinical symptoms could be demonstrated. PC-MRI did, however, reveal net CSF flow into the ventricular compartment in patients with pathological ICP pulsatility. This finding was supported by observations made in a study of CSF tracer (MRI contrast agent) propagation through the intracranial subarachnoid and brain compartments over a 24 hours` time span. Furthermore, the CSF tracer distributed at the brain surface along major artery trunks, but with delay in iNPH compared to references, and tracer clearance rate was also reduced in iNPH. At 24-hour scans, the tracer enriched brain tissue, indicating communication between the subarachnoid spaces and extra-vascular brain compartment. A paravascular pathway for brain clearance of cellular waste products, which was recently identified in rodent studies and denoted the “glymphatic” system, may thus also be present in humans. Glymphatic impairment in iNPH may possibly be instrumental in iNPH dementia.
Author: Geir Ringstad
Language: English
Subfield: Clinical Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2943433686