Syringomyelia Fluid Dynamics and Cord Motion Revealed by Serendipitous Null Point Artifacts during Cine MRI

Honey, C Michael; Martin, Kenneth W.; Heran, Manraj K. S.

doi:10.3174/ajnr.a5328

Cited by 12 publications

(9 citation statements)

References 13 publications

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“…Our finding of oscillatory flow in syrinx cavities is consistent with in vivo observations of syrinx fluid flow reported previously. Honey et al., 1 using dynamic MRI, observed oscillatory flow of fluid in a syrinx, but reported no velocity measurements. Similar to our findings, Lichtor et al.…”

Section: Discussionmentioning

confidence: 99%

“…Dynamic magnetic resonance imaging (MRI) in a patient with Chiari I and syringomyelia showed cranial and caudal fluid jets in syrinx fluid related to the cardiac cycle. 1 Phase-contrast MR (PC MR) in patients with Chiari I and syringomyelia have shown a spatially and temporally complex pattern of fluid movement in the syrinx. 2 Craniovertebral decompression altered flow in a Chiari I patient both in the subarachnoid space (SAS) and in the syrinx, and decreased syrinx velocities by an order of magnitude.…”

Section: Introductionmentioning

confidence: 99%

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Fluid dynamics in syringomyelia cavities: Effects of heart rate, CSF velocity, CSF velocity waveform and craniovertebral decompression

et al. 2018

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Purpose How fluid moves during the cardiac cycle within a syrinx may affect its development. We measured syrinx fluid velocities before and after craniovertebral decompression in a patient and simulated syrinx fluid velocities for different heart rates, syrinx sizes and cerebrospinal fluid (CSF) flow velocities in a model of syringomyelia. Materials and methods With phase-contrast magnetic resonance we measured CSF and syrinx fluid velocities in a Chiari patient before and after craniovertebral decompression. With an idealized two-dimensional model of the subarachnoid space (SAS), cord and syrinx, we simulated fluid movement in the SAS and syrinx with the Navier-Stokes equations for different heart rates, inlet velocities and syrinx diameters. Results In the patient, fluid oscillated in the syrinx at 200 to 210 cycles per minute before and after craniovertebral decompression. Velocities peaked at 3.6 and 2.0 cm per second respectively in the SAS and the syrinx before surgery and at 2.7 and 1.5 cm per second after surgery. In the model, syrinx velocity varied between 0.91 and 12.70 cm per second. Increasing CSF inlet velocities from 1.56 to 4.69 cm per second increased peak syrinx fluid velocities in the syrinx by 151% to 299% for the three cycle rates. Increasing cycle rates from 60 to 120 cpm increased peak syrinx velocities by 160% to 312% for the three inlet velocities. Peak velocities changed inconsistently with syrinx size. Conclusions CSF velocity, heart rate and syrinx diameter affect syrinx fluid velocities, but not the frequency of syrinx fluid oscillation. Craniovertebral decompression decreases both CSF and syrinx fluid velocities.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fluid dynamics in syringomyelia cavities: Effects of heart rate, CSF velocity, CSF velocity waveform and craniovertebral decompression

et al. 2018

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“…As indicated in the schematic of figure 1(c), the motion in the syrinx displays a sloshing character, with the internal fluid motion inducing cyclic variations of the cavity shape that can be visualized using high-resolution dynamic MRI (Honey, Martin & Heran 2017). This fluid slosh and its associated pressure fluctuations exert on the surrounding spinal cord tissue a cyclic traction that may contribute to the enlargement of the cavity (Honey et al 2017). As revealed by phase-contrast (PC) MRI measurements (Vinje et al 2018), the motion in the syrinx displays multiple oscillations per cardiac cycle, an intriguing feature of the flow resulting from the fluid-structure dynamical interactions taking place.…”

Section: Introductionmentioning

confidence: 99%

“…(2018) measured peak velocities of 3.6 and 2.0 cm s in the SAS and syrinx of a patient with Chiari I malformation, with the values decreasing to 2.7 and 1.5 cm s after the cavity shrank following surgery. As indicated in the schematic of figure 1( c ), the motion in the syrinx displays a sloshing character, with the internal fluid motion inducing cyclic variations of the cavity shape that can be visualized using high-resolution dynamic MRI (Honey, Martin & Heran 2017). This fluid slosh and its associated pressure fluctuations exert on the surrounding spinal cord tissue a cyclic traction that may contribute to the enlargement of the cavity (Honey et al.…”

Section: Introductionmentioning

confidence: 99%

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An analytic model for the flow induced in syringomyelia cavities

Nozaleda,

Alaminos-Quesada,

Coenen

et al. 2024

J. Fluid Mech.

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A simple two-dimensional fluid–structure interaction problem, involving viscous oscillatory flow in a channel separated by an elastic membrane from a fluid-filled slender cavity, is analysed to shed light on the flow dynamics pertaining to syringomyelia, a neurological disorder characterized by the appearance of a large tubular cavity (syrinx) within the spinal cord. The focus is on configurations in which the velocity induced in the cavity, representing the syrinx, is comparable to that found in the channel, representing the subarachnoid space surrounding the spinal cord, both flows being coupled through a linear elastic equation describing the membrane deformation. An asymptotic analysis for small stroke lengths leads to closed-form expressions for the leading-order oscillatory flow, and also for the stationary flow associated with the first-order corrections, the latter involving a steady distribution of transmembrane pressure. The magnitude of the induced flow is found to depend strongly on the frequency, with the result that for channel flow rates of non-sinusoidal waveform, as those found in the spinal canal, higher harmonics can dominate the sloshing motion in the cavity, in agreement with previous in vivo observations. Under some conditions, the cycle-averaged transmembrane pressure, also showing a marked dependence on the frequency, changes sign on increasing the cavity transverse dimension (i.e. orthogonal to the cord axis), underscoring the importance of cavity size in connection with the underlying hydrodynamics. The analytic results presented here can be instrumental in guiding future numerical investigations, needed to clarify the pathogenesis of syringomyelia cavities.

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