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CSF Flow in Chiari I and Syringomyelia. From the perspective of Computational Fluid Dynamics. Karen H. Støverud , K.-A. Mardal , V. Haughton , H.P. Langtangen Bologna, Oct . 6, 2010. This presentation aims to describe how abnormal CSF flow can affect the spinal cord. - PowerPoint PPT Presentation
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CSF Flow in Chiari I and SyringomyeliaFrom the perspective of Computational Fluid DynamicsKaren H. Støverud, K.-A. Mardal, V. Haughton, H.P. Langtangen
Bologna, Oct. 6, 2010
This presentation aims to describe how abnormal CSF flow can affect the spinal cord
1) Oscillatory CSF flow• Measurements• Simulations
2) Consequences of abnormal CSF flow on the spinal cord• Simulations
Why do Chiari patients develop syringomyelia?
CSF flow varies throughout the cardiac cycle, in relation with changing pressure gradients
Systole Diastole
The goal of PCMR is to identify patients that will benefit from surgery
Minor abnormalities
Major abnormalities
Limits:‒ Inaccurate
velocities‒ Low temporal
resolution
Today, computational models are used throughout all industries
…but to a little extent in medicine…
To gain a better insight of cyclic CSF flow and pressures, computational models are powerful tools.
MRI + Computer Models = Optimal Treatment
CSF flow in the subarachnoid space simulated by a computational model:
Complex flow:• Jets• Bidirectional flow• Greater flow anterior than posterior
• Variation along the spinal axis
Linge et al. 2010
Magnitude of flow varies both in the axial and sagittal plane
Geometries Velocity profiles
Roldan et al. 2009
Greater pressure gradients have been observed in Chiari patients than in normals
Steeper pressure gradient in regions of narrowed SAS
Roldan et al. 2009
Simulations of CSF flow have been validated by the means of PC MRI
Shah et al. 2009
Computer models have improved the understanding of CSF flow and pressure in the subarachnoid space
CSF flow is characterized by:1) Jets 2) Bidirectional flow3) Greater flow anterior than posterior
to the cord.4) Pressure gradient
Models• 3D• Velocity• Pressure
PCMR • 2D• Velocity
Investigating the effects of abnormal pressure gradients on the spinal cord tissue Spinal cord tissue as a poro-elastic medium:
We created an idealized model of the spinal cord and prescribed the pressure in the surrounding CSF
Fluid enters the spinal cord in regions of high pressure and leaves in regions of low pressure
Fluid accumulate in the spinal cord when a central canal with high permeability is added
The spinal cord contracts where the pressure is high and expands where the pressure is low
Blue: Tissue contracts
Orange: Tissue expands presyrinx develops
In conclusion, computational models may increase our understanding of CSF flow and syrinx formation
• Volume (3D) display of velocity and pressure• Greater spatial and temporal resolution• Demonstrates increased jets and bidirectional flow in Chiari
• Demonstrates steeper pressure gradients in Chiari• Including the central canal fluid accumulate in the spinal cord
• Predicts presyrinx state