Identification of Chiari Malformation Type I Brain Morphology and Biomechanics: A Multi-Faceted Approach to Determine Diagnostic and Treatment Criteria
| Autor: | Eppelheimer, Maggie S. |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Biomedical Engineering
Biomedical Research Medical Imaging Morphology Biomechanics Scientific Imaging Chiari Malformation type I neural tissue biomechanics brain morphology bone morphology neural tissue displacement neural tissue strain cerebrospinal fluid flow magnetic resonance imaging comorbid conditions posterior fossa decompression surgery |
| Druh dokumentu: | Text |
| Popis: | Individuals with Chiari malformation type I (CMI) demonstrate altered physiology that is characterized by the elongation of the cerebellar tonsils into the spinal canal. CMI patients experience many symptoms including occipital headaches, neck pain, and neurological deficits. In addition to the cerebellar tonsils, CMI patients demonstrate altered brain and bone morphology, cerebrospinal fluid (CSF) flow, and neural tissue dynamics. While previous studies identified brain morphology that differed between CMI patients and controls, these studies show inconsistent morphological differences. In Aim 1, we conducted multiple morphological examinations to identify possible sources of the inconsistent findings within the literature. Through quantification of over 50 two-dimensional (2D) morphometrics, we found many that distinguished CMI patients from healthy controls (28-32). However, only three comorbid conditions demonstrated morphology that differed between CMI patients with and without a comorbid condition. Additionally, seven morphometrics were found to differ from controls regardless of CMI comorbid conditions. As such, we identified 12 morphometrics that characterize the altered 2D morphology of CMI patients.Patients may be treated with posterior fossa decompression surgery to alter the physiological state of CMI patients and reduce symptoms. In Aim 2, we investigated the impact of the surgery on brain morphology and tissue dynamics. Surgery primarily impacted cerebellar morphology through reduced cerebellar height and larger CSF spaces around the cerebellum. Additionally, surgery resulted in a significant reduction in cerebellar and brainstem displacement and extension strain. While not significant, more associations were found between tissue dynamics and symptomatology than between brain morphology and clinical outcomes, suggesting that tissue dynamics have more prognostic value than brain morphology. In Aim 3, we investigated possible sources of neural tissue displacement. While cerebral blood volume expansion is believed to be a major contributor to neural tissue dynamics, our estimates indicated that pressure induced by CSF flow may be a greater contributor (>10x) to neural tissue motion. This dissertation demonstrated a multi-faceted approach to characterize the altered biomechanics of CMI patients. These findings indicate that future research should further evaluate the relationship between CSF induced pressure changes and tissue biomechanics, and whether this relationship can predict CMI symptomatology and clinical outcomes. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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