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Vartan Kurtcuoglu - One of the best experts on this subject based on the ideXlab platform.

  • Modelling of Cerebrospinal Fluid Flow by Computational Fluid Dynamics
    Biomechanics of the Brain, 2019
    Co-Authors: Vartan Kurtcuoglu, Kartik Jain, Bryn A. Martin
    Abstract:

    The movement of Cerebrospinal Fluid (CSF) is linked to the cardiovascular and respiratory systems. The heart not only drives blood Flow but is also at the origin of CSF pulsation through the expansion and contraction of cerebral blood vessels. Respiration modulates this cardiovascular action while also directly influencing spinal subarachnoid space (SAS) volume. CSF dynamics may be altered by pathologies such as hydrocephalus, Chiari malformation, syringomyelia and glioblastoma, and, in turn, dynamics of the CSF can be analysed to aid in disease diagnosis and prognosis. Several reviews delineate the current understanding of CSF motion [1–3]. This chapter describes the basic approach of and trends in computational Fluid dynamics (CFD) modelling of CSF Flow.

  • CILIA DOMINATE NEAR VENTRICULAR WALL Cerebrospinal Fluid Flow
    2013
    Co-Authors: Bercan Siyahhan, Dimos Poulikakos, Verena Knobloch, Diane De Zélicourt, Marianne Schmid Daners, Vartan Kurtcuoglu
    Abstract:

    There is a growing body of evidence suggesting that Cerebrospinal Fluid (CSF) Flow in the ventricular space contributes to neuronal guidance. However, it is unknown whether this is achieved predominantly through beating of the ependymal cilia or by macroscale pulsation of the ventricles and choroid plexus. We employed magnetic resonance imaging (MRI) to acquire subject-specific brain motion and Cerebrospinal Fluid Flow. Using computational Fluid dynamics (CFD), we evaluated the relative contributions of macroscale pulsatile CSF dynamics and cilia-induced Flow on the shear forces at the ventricular wall. When macroscale CSF pulsation is considered without the influence of motile cilia, periodic Flow reversals along the ventricular surface can be observed. This results in close to zero time-averaged shear stress on the ventricular walls. In the presence of cilia motion, Flow is forced in the anterior direction throughout the cardiac cycle close to the wall, with sharper velocity gradients due to the local Flow acceleration. This results in three orders of magnitude increase in wall shear stress. Our findings suggest that neuronal guidance mediated by CSF Flow is likely to be dominated by the action of the ependymal cilia. Conversely, CSF dynamics in the center regions of the ventricles are influenced mostly by wall motion and choroid plexus pulsation.

  • Pulsatile Cerebrospinal Fluid Flow in the cranial subarachnoid space
    Neurology Psychiatry and Brain Research, 2012
    Co-Authors: Vartan Kurtcuoglu
    Abstract:

    Summary Transport of biochemical substances and other species in the Cerebrospinal Fluid is influenced by the latter’s pulsatile Flow. By combining magnetic resonance imaging and computational Fluid dynamics, the Cerebrospinal Fluid Flow field can be reconstructed in a subject-specific manner. Here we describe the general Flow features in the cranial subarachnoid space as observed in a healthy volunteer.

  • Computational Fluid Dynamics for the Assessment of Cerebrospinal Fluid Flow and Its Coupling with Cerebral Blood Flow
    Biomechanics of the Brain, 2011
    Co-Authors: Vartan Kurtcuoglu
    Abstract:

    The dynamics of Cerebrospinal Fluid Flow are directly linked to those of the ­cardiovascular system. The heart not only drives blood Flow, but is also at the origin of CSF pulsation through the expansion and contraction of cerebral blood vessels. As was detailed in the preceding chapter, CSF dynamics can be altered by diseases and conditions such as hydrocephalus and, in turn, CSF dynamics can be analyzed to aid in the diagnosis of these. Bulk models describing intracranial Fluid dynamics and punctual Flow measurements using MRI have thus become important tools for this purpose.

  • Three-dimensional computational modeling of subject-specific Cerebrospinal Fluid Flow in the subarachnoid space.
    Journal of biomechanical engineering, 2008
    Co-Authors: Sumeet Gupta, Michaela Soellinger, Peter Boesiger, Dimos Poulikakos, Vartan Kurtcuoglu
    Abstract:

    This study aims at investigating three-dimensional subject-specific Cerebrospinal Fluid (CSF) dynamics in the inferior cranial space, the superior spinal subarachnoid space (SAS), and the fourth cerebral ventricle using a combination of a finite-volume computational Fluid dynamics (CFD) approach and magnetic resonance imaging (MRI) experiments. An anatomically accurate 3D model of the entire SAS of a healthy volunteer was reconstructed from high resolution T2 weighted MRI data. Subject-specific pulsatile velocity boundary conditions were imposed at planes in the pontine cistern, cerebellomedullary cistern, and in the spinal subarachnoid space. Velocimetric MRI was used to measure the velocity field at these boundaries. A constant pressure boundary condition was imposed at the interface between the aqueduct of Sylvius and the fourth ventricle. The morphology of the SAS with its complex trabecula structures was taken into account through a novel porous media model with anisotropic permeability. The governing equations were solved using finite-volume CFD. We observed a total pressure variation from -42 Pa to 40 Pa within one cardiac cycle in the investigated domain. Maximum CSF velocities of about 15 cms occurred in the inferior section of the aqueduct, 14 cms in the left foramen of Luschka, and 9 cms in the foramen of Magendie. Flow velocities in the right foramen of Luschka were found to be significantly lower than in the left, indicating three-dimensional brain asymmetries. The Flow in the cerebellomedullary cistern was found to be relatively diffusive with a peak Reynolds number (Re)=72, while the Flow in the pontine cistern was primarily convective with a peak Re=386. The net volumetric Flow rate in the spinal canal was found to be negligible despite CSF oscillation with substantial amplitude with a maximum volumetric Flow rate of 109 mlmin. The observed transient Flow patterns indicate a compliant behavior of the cranial subarachnoid space. Still, the estimated deformations were small owing to the large parenchymal surface. We have integrated anatomic and velocimetric MRI data with computational Fluid dynamics incorporating the porous SAS morphology for the subject-specific reconstruction of Cerebrospinal Fluid Flow in the subarachnoid space. This model can be used as a basis for the development of computational tools, e.g., for the optimization of intrathecal drug delivery and computer-aided evaluation of cerebral pathologies such as syrinx development in syringomelia.

U. Klose - One of the best experts on this subject based on the ideXlab platform.

  • Cerebrospinal Fluid Flow
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cardiac-related motion of the Cerebrospinal Fluid (CSF) was investigated by analysis of the velocity-dependent phase of CSF protons and Flow-dependent signal enhancement in magnitude images using ECG-gated FLASH sequences. In the cerebral aqueduct, CSF Flow from the third to the fourth ventricle begins 200 msafter the R-wave of the ECG and simulates an arterial pulse wave pattern. It lasts about 60% of the cardiac cycle and is followed by backFlow from the fourth to the third ventricle, which is slower and shorter. In the spinal canal, oscillating caudad motion precedes Flow from the third to the fourth ventricle by about 50–100 ms and issuperimposed on a bulk Flow, which moves simultaneously in opposite directions in separate subarachnoid channels; it is directed mainly caudally in the anterior cervical subarachnoid space.

  • Cerebrospinal Fluid Flow
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cerebrospinal Fluid (CSF) Flow in the cerebral aqueduct and spinal canal was analysed using real-time magnetic resonance imaging measurement techniques. Respiration-induced rhythmic modulation of the cardiacrelated oscillating CSF pulsation in the cerebral aqueduct and spinal canal was found. Deep inspiration was immediately followed by a marked increase in downward CSF Flow in the cervical spinal canal, whereas a delay of about two heart beats was seen before downward Flow from the third to the fourth ventricle increased. This pattern was also detected during yawning and was followed by a marked increase of blood Flow in the internal jugular vein.

  • Cerebrospinal Fluid Flow. I. Physiology of cardiac-related pulsation.
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cardiac-related motion of the Cerebrospinal Fluid (CSF) was investigated by analysis of the velocity-dependent phase of CSF protons and Flow-dependent signal enhancement in magnitude images using ECG-gated FLASH sequences. In the cerebral aqueduct, CSF Flow from the third to the fourth ventricle begins 200 ms after the R-wave of the ECG and simulates an arterial pulse wave pattern. It lasts about 60% of the cardiac cycle and is followed by backFlow from the fourth to the third ventricle, which is slower and shorter. In the spinal canal, oscillating caudad motion precedes Flow from the third to the fourth ventricle by about 50-100 ms and is superimposed on a bulk Flow, which moves simultaneously in opposite directions in separate subarachnoid channels; it is directed mainly caudally in the anterior cervical subarachnoid space.

Sumeet Gupta - One of the best experts on this subject based on the ideXlab platform.

  • Three-dimensional computational modeling of subject-specific Cerebrospinal Fluid Flow in the subarachnoid space.
    Journal of biomechanical engineering, 2008
    Co-Authors: Sumeet Gupta, Michaela Soellinger, Peter Boesiger, Dimos Poulikakos, Vartan Kurtcuoglu
    Abstract:

    This study aims at investigating three-dimensional subject-specific Cerebrospinal Fluid (CSF) dynamics in the inferior cranial space, the superior spinal subarachnoid space (SAS), and the fourth cerebral ventricle using a combination of a finite-volume computational Fluid dynamics (CFD) approach and magnetic resonance imaging (MRI) experiments. An anatomically accurate 3D model of the entire SAS of a healthy volunteer was reconstructed from high resolution T2 weighted MRI data. Subject-specific pulsatile velocity boundary conditions were imposed at planes in the pontine cistern, cerebellomedullary cistern, and in the spinal subarachnoid space. Velocimetric MRI was used to measure the velocity field at these boundaries. A constant pressure boundary condition was imposed at the interface between the aqueduct of Sylvius and the fourth ventricle. The morphology of the SAS with its complex trabecula structures was taken into account through a novel porous media model with anisotropic permeability. The governing equations were solved using finite-volume CFD. We observed a total pressure variation from -42 Pa to 40 Pa within one cardiac cycle in the investigated domain. Maximum CSF velocities of about 15 cms occurred in the inferior section of the aqueduct, 14 cms in the left foramen of Luschka, and 9 cms in the foramen of Magendie. Flow velocities in the right foramen of Luschka were found to be significantly lower than in the left, indicating three-dimensional brain asymmetries. The Flow in the cerebellomedullary cistern was found to be relatively diffusive with a peak Reynolds number (Re)=72, while the Flow in the pontine cistern was primarily convective with a peak Re=386. The net volumetric Flow rate in the spinal canal was found to be negligible despite CSF oscillation with substantial amplitude with a maximum volumetric Flow rate of 109 mlmin. The observed transient Flow patterns indicate a compliant behavior of the cranial subarachnoid space. Still, the estimated deformations were small owing to the large parenchymal surface. We have integrated anatomic and velocimetric MRI data with computational Fluid dynamics incorporating the porous SAS morphology for the subject-specific reconstruction of Cerebrospinal Fluid Flow in the subarachnoid space. This model can be used as a basis for the development of computational tools, e.g., for the optimization of intrathecal drug delivery and computer-aided evaluation of cerebral pathologies such as syrinx development in syringomelia.

G. Schroth - One of the best experts on this subject based on the ideXlab platform.

  • Cerebrospinal Fluid Flow
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cardiac-related motion of the Cerebrospinal Fluid (CSF) was investigated by analysis of the velocity-dependent phase of CSF protons and Flow-dependent signal enhancement in magnitude images using ECG-gated FLASH sequences. In the cerebral aqueduct, CSF Flow from the third to the fourth ventricle begins 200 msafter the R-wave of the ECG and simulates an arterial pulse wave pattern. It lasts about 60% of the cardiac cycle and is followed by backFlow from the fourth to the third ventricle, which is slower and shorter. In the spinal canal, oscillating caudad motion precedes Flow from the third to the fourth ventricle by about 50–100 ms and issuperimposed on a bulk Flow, which moves simultaneously in opposite directions in separate subarachnoid channels; it is directed mainly caudally in the anterior cervical subarachnoid space.

  • Cerebrospinal Fluid Flow
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cerebrospinal Fluid (CSF) Flow in the cerebral aqueduct and spinal canal was analysed using real-time magnetic resonance imaging measurement techniques. Respiration-induced rhythmic modulation of the cardiacrelated oscillating CSF pulsation in the cerebral aqueduct and spinal canal was found. Deep inspiration was immediately followed by a marked increase in downward CSF Flow in the cervical spinal canal, whereas a delay of about two heart beats was seen before downward Flow from the third to the fourth ventricle increased. This pattern was also detected during yawning and was followed by a marked increase of blood Flow in the internal jugular vein.

  • Cerebrospinal Fluid Flow. I. Physiology of cardiac-related pulsation.
    Neuroradiology, 1992
    Co-Authors: G. Schroth, U. Klose
    Abstract:

    Cardiac-related motion of the Cerebrospinal Fluid (CSF) was investigated by analysis of the velocity-dependent phase of CSF protons and Flow-dependent signal enhancement in magnitude images using ECG-gated FLASH sequences. In the cerebral aqueduct, CSF Flow from the third to the fourth ventricle begins 200 ms after the R-wave of the ECG and simulates an arterial pulse wave pattern. It lasts about 60% of the cardiac cycle and is followed by backFlow from the fourth to the third ventricle, which is slower and shorter. In the spinal canal, oscillating caudad motion precedes Flow from the third to the fourth ventricle by about 50-100 ms and is superimposed on a bulk Flow, which moves simultaneously in opposite directions in separate subarachnoid channels; it is directed mainly caudally in the anterior cervical subarachnoid space.

Takashi Yoshimoto - One of the best experts on this subject based on the ideXlab platform.

  • Quantitative analysis of Cerebrospinal Fluid Flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance imaging.
    Neurosurgery, 1999
    Co-Authors: Noriaki Watabe, Teiji Tominaga, Keiji Koshu, Hiroaki Shimizu, Takashi Yoshimoto
    Abstract:

    OBJECTIVE: To investigate changes in the Cerebrospinal Fluid Flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance (MR) imaging. METHODS: The participants included 44 healthy volunteers, 11 asymptomatic patients with evidence of degenerative changes of the cervical spine revealed by MR imaging but no neurological symptoms referable to those abnormalities, and 23 symptomatic patients with myelopathy who underwent surgery. Cervical spondylotic myelopathy was evaluated using the Japanese Orthopedic Association scores, and the percentage reduction of the transverse cord area at the level of maximum cord compression was measured on T1-weighted magnetic resonance images. A cine phase-contrast MR pulse sequence with peripheral gating was used to measure the Cerebrospinal Fluid Flow direction and velocity in the ventral subarachnoid spaces at the C1 and T1 levels. RESULTS: The velocity waveforms produced by plotting Flow velocity at 16 intervals during one cardiac cycle significantly differed among the healthy volunteers, asymptomatic patients, and preoperative symptomatic patients. However, velocity waveforms did not differ between the healthy volunteers and the postoperative patients at the C1 level. Decreases of Flow velocity were significantly correlated with the severity of myelopathy and the percentage reduction of cord area. Patients with severe myelopathy (Japanese Orthopedic Association score of 0-9 points) or greater than 30% reduction of cord area showed significantly decreased Flow velocity compared with those with mild myelopathy (Japanese Orthopedic Association score of 10-17 points) or less than 30% reduction of cord area. Changes in Flow velocity were not correlated with multiplicity of the lesion or the level of maximum cord compression. Postoperative improvement of Flow velocity was not correlated with neurological recovery. CONCLUSION: Cine phase-contrast MR imaging allows quantitative and noninvasive assessment of changes in Cerebrospinal Fluid Flow in patients with cervical spondylosis.

  • Transoral Decompression Evaluated by Cine-Mode Magnetic Resonance Imaging: A Case of Basilar Impression Accompanied by Chiari Malformation
    Neurosurgery, 1991
    Co-Authors: Teiji Tominaga, Keiji Koshu, Akira Ogawa, Takashi Yoshimoto
    Abstract:

    Abstract Cine-mode magnetic resonance imaging provides simultaneous images of Cerebrospinal Fluid Flow dynamics. A patient with a basilar impression accompanied by a Chiari malformation and von Recklinghausen's disease who underwent transoral decompression is reported. Preoperative cine-mode magnetic resonance imaging visualized an associated obstruction of Cerebrospinal Fluid pulsatile Flow at the level of the foramen magnum. Tonsilar herniation (Chiari I malformation) and hydrocephalus were also present. Postoperatively, the obstruction of Cerebrospinal Fluid Flow was resolved concomitant with the correction of the cervicomedullary angulation. On the basis of observations made by magnetic resonance imaging, the surgical treatment of basilar impression accompanied by Chiari malformation is briefly discussed.