Dynamics of lateral ventricle and cerebrospinal fluid in normal and hydrocephalic brains

Abstract

Purpose: To develop quantitative MRI techniques to measure, model, and visualize cerebrospinal fluid (CSF) hydrodynamics in normal subjects and hydrocephalic patients. Materials and Methods:Velocity information was obtained using time-resolved (CINE) phase-contrast imaging of different brain regions. A technique was developed to measure the change of lateral ventricle (LV) size. The temporal relationships between the LV size change, CSF movement, and blood flow could then be established. The data were incorporated into a first-principle CSF hydrodynamic model. The model was then used to generate specific predictions about CSF pressure relationships. To better-visualize the CSF flow, a color-coding technique based on linear transformations was developed that represents the magnitude and direction of the velocity in a single cinematic view. Results:The LV volume change of the eight normal subjects was 0.901 Ϯ 0.406%. Counterintuitively, the LV decreases as the choroid plexus expands, so that they act together to produce the CSF oscillatory flow. The amount of oscillatory flow volume is 21.7 Ϯ 10.6% of the volume change of the LV from its maximum to its minimum. Conclusion:The quantification and visualization techniques, together with the mathematical model, provide a unique approach to understanding CSF flow dynamics.

Cine cerebrospinal fluid imaging in multiple sclerosis

“…We found a correlation between aqueductal CSF flow and lateral ventricle size in the MS patients, similar to what has already been found in healthy controls (42). A similar observation was found with measuring the short axis length of the AoS, as calculated by MACC (Table 3).…”

“…It is possible that the 3VW, 4VV, and NLVV increase to compensate for the altered pulsatile flow. In fact, it has been previously shown that there is a moderately strong (R 2 ¼ 0.8) correlation between pulsatile flow and LVV (42). This could explain why there was no correlation between NLVV and any flow measure in CIS patients, as the dynamic flow alterations may not be fully visible at this early stage of the disease, or are actively developing.…”

“…There was also a trend for correlation in all MS patients between pulsatile flow and increased T2-LV (net negative flow r ¼ À0.28, net positive flow r ¼ 0.30, P ¼ 0.02 for both) and T1-LV (r ¼ À0.39 and P ¼ 0.002, r ¼ À0. 42 and P ¼ 0.001, respectively). The relationship between CSF measures and conventional MRI outcomes in patients …”

Vascular Coupling in Resting-State FMRI: Evidence from Multiple Modalities

“…A spectral peak around 0.06 Hz was also observed in the CSF and WM signals, probably due to the tight coupling between CSF and brain motions with a low amplitude. 37 After the 'global-CSF-WM regression and low-pass filtering' procedure, spectral power of BOLD signal was reduced substantially by more than 55.6% in all observed brain regions. Furthermore, with this preprocessing procedure, coherences of BOLD fluctuations between the withinnetwork regions were reduced by 9.9% to 20.0%, and by 22.5% to 37.3% between the outside-network regions.…”

The Physics of Hydrocephalus

“…In doing so, we take advantage of new computer-based mathematical techniques, MRI studies, and pressure monitoring which were not available 30 years ago. Much of our experimental work has been presented in engineering and imaging literature [2,3,4]. Since the goal is to advance understanding and improve neurosurgical treatments for brain diseases and in particular hydrocephalus, this review article is designed to present in a clear, relatively nontechnical manner our main findings leading to a comprehensive quantitative picture of intracranial dynamics and their implications for clinical practice.…”