Imaging and health metrics in incidental cerebellar tonsillar ectopia: findings from the Adolescent Brain Cognitive Development Study (ABCD)

• Published in: Neuroradiology Vol. 63; no. 11; pp. 1913 - 1924
• Main Authors: Nwotchouang, Blaise Simplice Talla, Ibrahimy, Alaaddin, Loth, Dorothy M., Labuda, Edward, Labuda, Nicholas, Eppleheimer, Maggie, Labuda, Richard, Bapuraj, Jayapalli Rajiv, Allen, Philip A., Klinge, Petra, Loth, Francis
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-11-2021; Springer Nature B.V
• Subjects: Adolescents; Body mass; Body mass index; Body size; Brain; Cerebellum; Cerebrospinal fluid; Cognitive ability; Cognitive development; Congenital defects; Control equipment; Females; Imaging; Magnetic resonance imaging; Males; Medicine; Medicine & Public Health; Minority & ethnic groups; Morphology; Morphometry; Neural tube defects; Neuroimaging; Neurology; Neuroradiology; Neurosciences; Neurosurgery; Paediatric Neuroradiology; Pediatrics; Radiology; Skull; Teenagers; Tonsil; Magnetic resonance imaging; Chiari malformation type I; Adolescent Brain Cognitive Development (ABCD) pediatric study; Brain morphometrics; Incidental cerebellar tonsillar ectopia
• ISSN: 0028-3940; 1432-1920
• DOI: 10.1007/s00234-021-02759-y

Purpose
Incidental cerebellar tonsillar ectopia (ICTE) that meets the radiographic criterion for Chiari malformation type I (CMI) is an increasingly common finding in the clinical setting, but its significance is unclear. The present study examined posterior cranial fossa (PCF) morphometrics and a broad range of health instruments of pediatric ICTE cases and matched controls extracted from the Adolescent Brain Cognitive Development (ABCD) dataset.
Methods
One-hundred-six subjects with ICTE and 106 matched controls without ICTE were identified from 11,411 anatomical MRI of healthy screened pediatric subjects from the ABCD project. Subjects were matched by sex, age, body mass index, race, and ethnicity. Twenty-two brain morphometrics and 22 health instruments were compared between the two groups to identify unrecognized CMI symptoms and assess the general health impact of ICTE.
Results
Twelve and 15 measures were significantly different between the ICTE and control groups for females and males, respectively. Notably, for females, the anterior CSF space was significantly smaller (
p
 = 
0.00005)
for the ICTE group than controls. For males, the clivus bone length was significantly shorter (
p
 = 
0.0002)
for the ICTE group compared to controls. No significant differences were found among the 22 health instruments between the two groups.
Conclusion
This study demonstrated that pediatric ICTE subjects have similar PCF morphometrics to adult CMI. ICTE alone did not appear to cause any unrecognized CMI symptoms and had no impact on the subjects’ current mental, physical, or behavioral health. Still, given their cranial and brain morphology, these cases may be at risk for adult-onset symptomatic CMI.