Quantification of Cerebellar Crowding in Type I Chiari Malformation

Abstract

This study was focused on a semi-automated morphometric analysis of the cerebellum in the mid-sagittal plane as an alternative to tonsillar descent alone in the evaluation of Chiari malformation type 1 (CMI) patients. Morphometric analyses of posterior fossa structures were performed on mid-sagittal MRI images of 375 individuals (females, > 18 years, 235 CMI and 140 healthy controls). Twenty-six parameters including linear, angular and area measurements together with non-dimensional ratios were calculated. Eighteen parameters were found to be significantly different between CMI and control subjects. Smaller posterior cranial fossa (PCF) area in CMI subjects was attributed to a smaller PCF area anterior to the brainstem. The cerebellar area was found to be larger in CMI subjects as compared to controls (15.1%), even without inclusion of the tonsillar area below the foramen magnum (FM) (8.4%). The larger cerebellar area in CMI subjects was due to cranialcaudal elongation of the cerebellum, predominately below the fastigium. The cerebrospinal fluid spaces below the FM were smaller in CMI subjects as compared to controls. Overall, greater cerebellar crowding was identified in CMI subjects relative to healthy controls. These observations may improve our understanding of the pathophysiology of CMI in adult female patients.

Correlation of a new hydrodynamic index with other effective indexes in Chiari I malformation patients with different associations

“…Assessment of morphological changes in CM-I patients is of great significance for predicting surgery risks and assessing patients’ conditions 8 , 12 , and craniospinal size changes are among the most obvious changes in these patients. Some studies have presented CSF volume changes during the incidence of CM-I as a highly prognostic and valuable parameter 84 .…”

“…The primary diagnosis of this disease is achieved generally with neuroimaging techniques. The reason is that the incidence of CM-I is usually accompanied by obvious morphological and volumetric changes in patients 8,12 . Accordingly, several studies have used morphological and volumetric changes in patients as a diagnostic parameter and an index for investigating the severity of the disease and/or efficacy of surgery [13][14][15][16][17][18] .…”

“…Some studies have investigated the relationship between different morphometric and volumetric parameters affecting this disease or the relationship between these parameters and patients' symptoms 2,19 . Despite all these efforts and advances in neuroimaging technologies, there are still different and sometimes conflicting opinions about which morphological and volumetric parameters are more effective and relevant than other parameters 12,17,[20][21][22][23][24][25][26][27][28] . For example, some studies have considered the reduction of posterior cranial fossa (PCF) volume as the primary characteristic of CM-I 17,29,30 .…”

“Stealth Cranioplasty” for Adult Chiari Malformation Type 1: A Philosophical Journey of Innovation, Adaptation, and Evolution

“…Interestingly, in cases of acquired Chiari malformation (ACM), surgical management of only the primary lesion has shown to improve ACM which also supports the discrepancy between the volume of the posterior fossa and its contents [39]. From different studies, it is now proposed that development of Chiari results from multifactorial etiologies, where small PF remains to be the most crucial one [40][41][42][43][44][45][46][47][48][49][50][51][52]. The theory of small PF is further strengthened by demonstration of CM by creating smaller basichondrocrania and posterior cranial fossa than controls by producing a state of hypervitaminosis A in experimental models of rodents [53].…”

Evidence for sex differences in morphological abnormalities in type I Chiari malformation

“…CMI is also three times more likely to be identified in women than in men. [1][2][3][4][5] While traditionally characterized by the descent of the cerebellar tonsils >3-5 mm below the foramen magnum, 6,7 additional morphological characteristics, including the lowering of PCF structures relative to the foramen magnum, the sharper angulation of the clivus in relation to the odontoid process, and the retroflexion of the odontoid process, have been identified. 1 However, individual differences in these presentations, such as the influence of age, sex, and body mass index (BMI), have received little attention and have led to two problematic consequences.…”