As noted in a previous entry, the definition of the Chiari malformations is under flux. The value of a classification system is directly related to its pertinence in clinical decision-making. The neurological impact of a Type I malformation varies widely: one person with 5 mm of herniation may be terribly symptomatic, while another with 15 mm may not be bothered at all.
The patient’s symptoms, neurological findings, degree of tonsillar herniation, and the amount of crowding and distortion of the brain stem are all used in making treatment decisions. When there is uncertainty, CSF flow analysis using phase-contrast MRI can be obtained. However, different radiologists may read the study differently.
Clearly, better tools are needed to diagnose and assess neurophysiological effects of CM-I. Fortunately, the C&S Patient Education Foundation has recently funded such a study. A team of researchers from multiple institutions have designed a study that hopes to “distinguish symptomatic Chiari I patients who require treatment, from individuals with asymptomatic Chiari I (incidental tonsillar ectopia)”.
The research team will evaluate “specific measurements of anatomic geometry and phase contrast magnetic resonance imaging” in 7 volunteers, 7 persons with CM-I but without symptoms, and 7 persons symptomatic from CM-I. The following four parameters will be assessed in each patient:
Computational fluid dynamics:
“Compute the cerebrospinal fluid pressures and velocities within the subarachnoid space above and below the foramen magnum.”
Longitudinal impedance:
Calculate the “resistance in the subarachnoid space to the flow of CSF at the C2 level.”
Pulse wave velocity (PWV):
Measure the pulse wave speed within the subarachnoid space. PWV is “thought to be an indicator of the compliance within the spinal canal.”
CSF volume and skull based geometry:
Calculate the CSF volume and skull based geometry from the each persons scans.
The results will be correlated to disease severity. The hope is that one or more of these measures will be useful in determining the presence, and the neurophysiological impact, of CM-I. These studies could then serve as tools to help a physician determine if treatment is needed. They might also help neurosurgeons decide the extent of the surgical decompression required.
Posted by
John Oro’, MD
As noted in a previous entry, the definition of the Chiari malformations is under flux. The value of a classification system is directly related to its pertinence in clinical decision-making. The neurological impact of a Type I malformation varies widely: one person with 5 mm of herniation may be terribly symptomatic, while another with 15 mm may not be bothered at all.
The patient’s symptoms, neurological findings, degree of tonsillar herniation, and the amount of crowding and distortion of the brain stem are all used in making treatment decisions. When there is uncertainty, CSF flow analysis using phase-contrast MRI can be obtained. However, different radiologists may read the study differently.
Clearly, better tools are needed to diagnose and assess neurophysiological effects of CM-I. Fortunately, the C&S Patient Education Foundation has recently funded such a study. A team of researchers from multiple institutions have designed a study that hopes to “distinguish symptomatic Chiari I patients who require treatment, from individuals with asymptomatic Chiari I (incidental tonsillar ectopia)”.
The research team will evaluate “specific measurements of anatomic geometry and phase contrast magnetic resonance imaging” in 7 volunteers, 7 persons with CM-I but without symptoms, and 7 persons symptomatic from CM-I. The following four parameters will be assessed in each patient:
Computational fluid dynamics:
“Compute the cerebrospinal fluid pressures and velocities within the subarachnoid space above and below the foramen magnum.”
Longitudinal impedance:
Calculate the “resistance in the subarachnoid space to the flow of CSF at the C2 level.”
Pulse wave velocity (PWV):
Measure the pulse wave speed within the subarachnoid space. PWV is “thought to be an indicator of the compliance within the spinal canal.”
CSF volume and skull based geometry:
Calculate the CSF volume and skull based geometry from the each persons scans.
The results will be correlated to disease severity. The hope is that one or more of these measures will be useful in determining the presence, and the neurophysiological impact, of CM-I. These studies could then serve as tools to help a physician determine if treatment is needed. They might also help neurosurgeons decide the extent of the surgical decompression required.
Posted by John Oro’, MD