Morphometric Analysis of Predictors of Cervical Syrinx Formation in the Setting of Chiari I Malformation

Halvorson, Kyle G.; Kellogg, Ryan T; Keachie, Krista; Grant, Gerald A.; Muh, Carrie R.; Waldau, Ben

doi:10.1159/000442991

Cited by 16 publications

(6 citation statements)

References 24 publications

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“…89% of the cases in our series were associated with syringomyelia, higher than the 20-72% in previous reports [5]. Since syringomyelia is usually secondary to tonsillar herniation, and syringomyelia formation is irrelevant to the PCF volume [35], these differences should not affect our conclusions. Secondly, CT images may be more difficult to show the tentorium in all slices, compared to MRI [14], so the bony PCF in this study does not include the upper part of the total PCF under the tentorium.…”

Section: Discussioncontrasting

confidence: 60%

Morphometric and volumetric analysis of the posterior cranial fossa in adult Chiari malformation type I with and without group B basilar invagination

Xia¹,

Xia²,

Tang³

et al. 2022

J. Integr. Neurosci.

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Background:The frequent association of basilar invagination (BI) makes the understanding of the pathogenesis of Chiari malformation type I (CMI) difficult. The influence of group B type of BI (the BI without obvious atlantoaxial instability) on the skeletal morphology has not been thoroughly studied. The objective of this study is to evaluate the skeletal alterations in the posterior cranial fossa (PCF) of adult CMI cases with and without group B BI. Methods: Fifty-four adult CMI without BI cases (CMI-only group) and 30 adult CMI with group B BI cases (CMI-BI group) were retrospectively studied. Fifty-six adult patients with unruptured intracranial aneurysms were included as the controls. Several linear and angular variables, and the bony volume of the PCF were analyzed based on thin-slice computed tomography data. Results: Morphological analysis revealed a significant difference in several variables from controls compared to CMI-only, and CMI-BI patients. The clivus and occipital bone, shortened and elevated in CMI-only patients, were further flattened in BI-associated CMI patients. Furthermore, although out of the scope for the diagnostic threshold of BI, the CMI-only cases also had a tendency to form BI. The association of BI modified several variables, without further reducing the bony PCF volume. Conclusions: These findings indicate that the variables associated with group B BI tend to be a continuum of the same pathological abnormalities that originate from the same pathological alterations in CMI patients.

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Section: Discussioncontrasting

confidence: 60%

Morphometric and volumetric analysis of the posterior cranial fossa in adult Chiari malformation type I with and without group B basilar invagination

Xia¹,

Xia²,

Tang³

et al. 2022

J. Integr. Neurosci.

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“…We used the previously described methods to measure posterior fossa structures. 9,[19][20][21][22][23][24][25] Details in e-methods (links.lww. com/NXG/A252).…”

Section: Measurementsmentioning

confidence: 99%

Neuraxial dysraphism in EPAS1- associated syndrome due to improper mesenchymal transition

et al. 2020

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ObjectiveTo investigate the effect of somatic, postzygotic, gain-of-function mutation of Endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) encoding hypoxia-inducible factor-2α (HIF-2α) on posterior fossa development and spinal dysraphism in EPAS1 gain-of-function syndrome, which consists of multiple paragangliomas, somatostatinoma, and polycythemia.MethodsPatients referred to our institution for evaluation of new, recurrent, and/or metastatic paragangliomas/pheochromocytoma were confirmed for EPAS1 gain-of-function syndrome by identification of the EPAS1 gain-of-function mutation in resected tumors and/or circulating leukocytes. The posterior fossa, its contents, and the spine were evaluated retrospectively on available MRI and CT images of the head and neck performed for tumor staging and restaging. The transgenic mouse model underwent Microfil vascular perfusion and subsequent intact ex vivo 14T MRI and micro-CT as well as gross dissection, histology, and immunohistochemistry to assess the role of EPAS1 in identified malformations.ResultsAll 8 patients with EPAS1 gain-of-function syndrome demonstrated incidental posterior fossa malformations—one Dandy-Walker variant and 7 Chiari malformations without syringomyelia. These findings were not associated with a small posterior fossa; rather, the posterior fossa volume exceeded that of its neural contents. Seven of 8 patients demonstrated spinal dysraphism; 4 of 8 demonstrated abnormal vertebral segmentation. The mouse model similarly demonstrated features of neuraxial dysraphism, including cervical myelomeningocele and spinal dysraphism, and cerebellar tonsil displacement through the foramen magnum. Histology and immunohistochemistry demonstrated incomplete mesenchymal transition in the mutant but not the control mouse.ConclusionsThis study characterized posterior fossa and spinal malformations seen in EPAS1 gain-of-function syndrome and suggests that gain-of-function mutation in HIF-2α results in improper mesenchymal transition.

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“…The identification of morphometric indicators for the diagnosis of CM-I as an alternative to TH has already been attempted. 3,20,42,51,55 The novelty of the present study was in the use of a larger classic CM-I patient cohort and the application of 7 different supervised machine-learning methods. These methods "learned" automatically from data obtained in diagnosed CM-I cases and predicted whether a new undiagnosed patient belonged either to the classic CM-I group or the control group.…”

Section: Machine-learning Approach For the Improvement Of Cm-i Diagnosismentioning

confidence: 99%

“…While these results were strong, the measurement methodology applied re-quired volumetric postprocessing that might not be available in many clinics and was very time consuming, since it required the measurement of several morphometric traits. Other studies that focused on the comparison of morphometric measurements between CM-I patients with and without a syrinx found significant correlations between the degrees of TH and syrinx formation; 20,46 furthermore, either the clivus slope or the PCF depth was observed to be significantly smaller in CM-I patients with a syrinx. 42,55 However, these results have not yet been replicated.…”

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confidence: 93%

Machine learning applied to neuroimaging for diagnosis of adult classic Chiari malformation: role of the basion as a key morphometric indicator

Urbizu¹,

Martin

Moncho

et al. 2018

Journal of Neurosurgery

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OBJECTIVE The current diagnostic criterion for Chiari malformation Type I (CM-I), based on tonsillar herniation (TH), includes a diversity of patients with amygdalar descent that may be caused by a variety of factors. In contrast, patients presenting with an overcrowded posterior cranial fossa, a key characteristic of the disease, may remain misdiagnosed if they have little or no TH. The objective of the present study was to use machine-learning classification methods to identify morphometric measures that help discern patients with classic CM-I to improve diagnosis and treatment and provide insight into the etiology of the disease. METHODS Fifteen morphometric measurements of the posterior cranial fossa were performed on midsagittal T1-weighted MR images obtained in 195 adult patients diagnosed with CM. Seven different machine-learning classification methods were applied to images from 117 patients with classic CM-I and 50 controls matched by age and sex to identify the best classifiers discriminating the 2 cohorts with the minimum number of parameters. These classifiers were then tested using independent CM cohorts representing different entities of the disease. RESULTS Machine learning identified combinations of 2 and 3 morphometric measurements that were able to discern not only classic CM-I (with more than 5 mm TH) but also other entities such as classic CM-I with moderate TH and CM Type 1.5 (CM-1.5), with high accuracy (> 87%) and independent of the TH criterion. In contrast, lower accuracy was obtained in patients with CM Type 0. The distances from the lower aspect of the corpus callosum, pons, and fastigium to the foramen magnum and the basal and Wackenheim angles were identified as the most relevant morphometric traits to differentiate these patients. The stronger significance (p < 0.01) of the correlations with the clivus length, compared with the supraoccipital length, suggests that these 5 relevant traits would be affected more by the relative position of the basion than the opisthion. CONCLUSIONS Tonsillar herniation as a unique criterion is insufficient for radiographic diagnosis of CM-I, which can be improved by considering the basion position. The position of the basion was altered in different entities of CM, including classic CM-I, classic CM-I with moderate TH, and CM-1.5. The authors propose a predictive model based on 3 parameters, all related to the basion location, to discern classic CM-I with 90% accuracy and suggest considering the anterior alterations in the evaluation of surgical procedures and outcomes.

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Morphometric Analysis of Predictors of Cervical Syrinx Formation in the Setting of Chiari I Malformation

Cited by 16 publications

References 24 publications

Morphometric and volumetric analysis of the posterior cranial fossa in adult Chiari malformation type I with and without group B basilar invagination

Morphometric and volumetric analysis of the posterior cranial fossa in adult Chiari malformation type I with and without group B basilar invagination

Neuraxial dysraphism in EPAS1- associated syndrome due to improper mesenchymal transition

Machine learning applied to neuroimaging for diagnosis of adult classic Chiari malformation: role of the basion as a key morphometric indicator

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