A model for the oscillatory flow in the cerebral aqueduct

Sincomb, S.; Coenen, Wilfried; Sánchez, Antonio L.; Lasheras, Juan C.

doi:10.1017/jfm.2020.463

Cited by 12 publications

(29 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pressure difference between the third and fourth ventricles was calculated using the fully nondimensional computational fluid dynamics method previously described in Sincomb et al 15 The reader is referred to this publication for the details of the computational fluid dynamics model. The corresponding computer codes to calculate the transmantle pressure will be made available by the authors on request.…”

Section: Transmantle Pressure Computationmentioning

confidence: 99%

“…Plot of aqueductal flow (left) in a healthy 37-year-old man with an average heart rate of 67 beats per minute. Plot of the transmantle pressure (right) after entering variables into the nondimensional model 15 and converting back to dimensional pressure (in Pascals). On the plot of transmantle pressure, the peak positive (DP 1 ) and negative (Dp -) transmantle pressures are demonstrated by arrows representing peak pressures during caudal and rostral aqueductal flow, respectively.…”

Section: Flow Analysismentioning

confidence: 99%

“…The goal of this study was to compute transmantle pressure from noninvasive aqueductal flow measurements using a simplified nondimensional fluid mechanics model previously published by Sincomb et al, 15 which accounts for the specific anatomic features of the aqueduct and relevant effects of local fluid acceleration, convective acceleration, and viscous forces. We applied this novel methodology to a group of volunteers to investigate differences related to age, sex, flow, and variations such as stroke volume, aqueductal length, and cross-sectional area on the transmantle pressure.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Transmantle Pressure Computed from MR Imaging Measurements of Aqueduct Flow and Dimensions

Sincomb

Coenen

Criado-Hidalgo

et al. 2021

AJNR Am J Neuroradiol

Self Cite

View full text Add to dashboard Cite

BACKGROUND AND PURPOSE: Measuring transmantle pressure, the instantaneous pressure difference between the lateral ventricles and the cranial subarachnoid space, by intracranial pressure sensors has limitations. The aim of this study was to compute transmantle pressure noninvasively with a novel nondimensional fluid mechanics model in volunteers and to identify differences related to age and aqueductal dimensions. MATERIALS AND METHODS:Brain MR images including cardiac-gated 2D phase-contrast MR imaging and fast-spoiled gradient recalled imaging were obtained in 77 volunteers ranging in age from 25-92 years of age. Transmantle pressure was computed during the cardiac cycle with a fluid mechanics model from the measured aqueductal flow rate, stroke volume, aqueductal length and cross-sectional area, and heart rate. Peak pressures during caudal and rostral aqueductal flow were tabulated. The computed transmantle pressure, aqueductal dimensions, and stroke volume were estimated, and the differences due to sex and age were calculated and tested for significance.RESULTS: Peak transmantle pressure was calculated with the nondimensional averaged 14.4 (SD, 6.5) Pa during caudal flow and 6.9 (SD, 2.8) Pa during rostral flow. It did not differ significantly between men and women or correlate significantly with heart rate. Peak transmantle pressure increased with age and correlated with aqueductal dimensions and stroke volume. CONCLUSIONS:The nondimensional fluid mechanics model for computing transmantle pressure detected changes in pressure related to age and aqueductal dimensions. This novel methodology can be easily used to investigate the clinical relevance of the transmantle pressure in normal pressure hydrocephalus, pediatric communicating hydrocephalus, and other CSF disorders.

show abstract

Section: Transmantle Pressure Computationmentioning

confidence: 99%

Section: Flow Analysismentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Transmantle Pressure Computed from MR Imaging Measurements of Aqueduct Flow and Dimensions

Sincomb

Coenen

Criado-Hidalgo

et al. 2021

AJNR Am J Neuroradiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since the interventricular pressure difference ∆p(t) drives the flow in the aqueduct, the transmantle pressure can be inferred from noninvasive MRI measurements of the oscillatory aqueduct flow rate Q(t) [17], with the pressure differences associated with the cardiac-driven flow being about four times larger than those associated with respiration [25]. Different models have been developed for the relation between ∆p(t) and Q(t) [17,27,28], needed to enable estimates of the former from measurements of the latter [29]. As shown previously [28], accurate predictions require consideration of effects of flow acceleration as well pressure losses at the nearly inviscid entrance regions connecting the aqueduct with the ventricles.…”

Section: Introductionmentioning

confidence: 99%

An In-Vitro Experimental Investigation of Oscillatory Flow in the Cerebral Aqueduct

Sincomb

Moral-Pulido

Campos

et al. 2023

Preprint

View full text Add to dashboard Cite

Background: The cerebrospinal fluid filling the ventricles of the brain moves with a cyclic velocity driven by the transmantle pressure, or instantaneous pressure difference between the lateral ventricles and the cerebral subarachnoid space. This dynamic phenomenon is of particular interest for understanding ventriculomegaly in cases of normal pressure hydrocephalus (NPH). The magnitude of the transmantle pressure is small, on the order of a few Pascals, thereby hindering direct in vivo measurements. To complement previous computational efforts, we perform here, for the first time, in vitro experiments involving an MRI-informed experimental model of the cerebral aqueduct flow. Methods: Dimensional analysis is used in designing a scaled-up model of the aqueduct flow, with physical similarity maintained by adjusting the flow frequency and the properties of the working fluid. High-resolution MRI images are used to generate a 3D-printed anatomically correct aqueduct model. A programmable pump is used to generate a pulsatile flow rate signal measured from phase-contrast MRI. Extensive experiments are performed to investigate the relation between the cyclic fluctuations of the aqueduct flow rate and the transmantle pressure fluctuation over the range of flow conditions commonly encountered in healthy subjects. The time-dependent pressure measurements are validated through comparisons with predictions obtained with a previously derived computational model. Results: Parametric dependences of the pressure-fluctuation amplitude and its phase lag relative to the flow rate are delineated. The results indicate, for example, that the phase lag is nearly independent on the stroke volume. A simple expression relating the mean amplitude of the interventricular pressure difference (between third and fourth ventricle) with the stroke volume of the oscillatory flow is established. Conclusions: MRI-informed in-vitro experiments using an anatomically correct model of the cerebral aqueduct and a realistic flow rate have been used to characterize transmantle pressure. The quantitative results can be useful in enabling quick clinical assessments of transmantle pressure to be made from noninvasive phase contrast MRI measurements of aqueduct flow rates. The scaled-up experimental facility provides the ability to conduct future experiments specifically aimed at investigating altered CSF flow and associated transmantle pressure, as needed in connection with NPH studies.

show abstract

“…2021; Coenen, Zhang & Sánchez 2021) and along the cerebral aqueduct (Sincomb et al. 2020, 2021), for example. The present paper deals with the motion along the SSAS, a slender compliant canal of length bounded internally by the pia mater surrounding the spinal cord and externally by the deformable dura membrane (see figure 1 a ).…”

Section: Introductionmentioning

confidence: 99%

A one-dimensional model for the pulsating flow of cerebrospinal fluid in the spinal canal

et al. 2022

Self Cite

View full text Add to dashboard Cite

The monitoring of intracranial pressure (ICP) fluctuations, which is needed in the context of a number of neurological diseases, requires the insertion of pressure sensors, an invasive procedure with considerable risk factors. Intracranial pressure fluctuations drive the wave-like pulsatile motion of cerebrospinal fluid (CSF) along the compliant spinal canal. Systematically derived simplified models relating the ICP fluctuations with the resulting CSF flow rate can be useful in enabling indirect evaluations of the former from non-invasive magnetic resonance imaging (MRI) measurements of the latter. As a preliminary step in enabling these predictive efforts, a model is developed here for the pulsating viscous motion of CSF in the spinal canal, assumed to be a linearly elastic compliant tube of slowly varying section, with a Darcy pressure-loss term included to model the fluid resistance introduced by the trabeculae, which are thin collagen-reinforced columns that form a web-like structure stretching across the spinal canal. Use of Fourier-series expansions enables predictions of CSF flow rate for realistic anharmonic ICP fluctuations. The flow rate predicted using a representative ICP waveform together with a realistic canal anatomy is seen to compare favourably with in vivo phase-contrast MRI measurements at multiple sections along the spinal canal. The results indicate that the proposed model, involving a limited number of parameters, can serve as a basis for future quantitative analyses targeting predictions of ICP temporal fluctuations based on MRI measurements of spinal-canal anatomy and CSF flow rate.

show abstract

A model for the oscillatory flow in the cerebral aqueduct

Abstract: Abstract

Cited by 12 publications

References 28 publications

Transmantle Pressure Computed from MR Imaging Measurements of Aqueduct Flow and Dimensions

Transmantle Pressure Computed from MR Imaging Measurements of Aqueduct Flow and Dimensions

An In-Vitro Experimental Investigation of Oscillatory Flow in the Cerebral Aqueduct

A one-dimensional model for the pulsating flow of cerebrospinal fluid in the spinal canal

Contact Info

Product

Resources

About