Normal range of clivoaxial angle in adults using flexion and extension cervical magnetic resonance imaging scans.
Citation: Neuroradiology Journal. 34(4):348-354, 2021 Aug.PMID: 33678065Institution: MedStar Washington Hospital CenterDepartment: NeuroradiologyForm of publication: Journal ArticleMedline article type(s): Journal ArticleSubject headings: *Magnetic Resonance Imaging | *Neck | Adult | Cervical Vertebrae/dg [Diagnostic Imaging] | Humans | Neck/dg [Diagnostic Imaging] | Range of Motion, Articular | Reference Values | Tomography, X-Ray ComputedYear: 2021ISSN:- 1971-4009
Item type | Current library | Collection | Call number | Status | Date due | Barcode |
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Journal Article | MedStar Authors Catalog | Article | 33678065 | Available | 33678065 |
CONCLUSIONS: We report normal ranges for CXA in various neck positions based on 3D T2-weighted MRI, using a reproducible measurement method. There was a significant difference in the CXA values between neck extended and neck flexed positions but not between supine and prone positions.
METHODS: The CXA was measured in 10 healthy volunteers on sagittal T2 SPACE c-spine MRI in supine and prone positions and with the neck both neck and extended. CXA is strictly defined as the angle between a line along the inferior third of the dorsal clival cortex and a line from the superior/posterior cortex of the dens to the posterior/inferior corner of the C2 body. Statistical analysis was performed in all positions and included mean CXA, range, standard deviation (SD), inter-reader agreement, and group comparisons.
OBJECTIVE: An abnormally decreased clivoaxial angle (CXA) is used during the clinical evaluation for corrective skull base surgery. Published normal ranges of CXA using x-ray, computed tomography, or magnetic resonance imaging (MRI) vary dramatically, especially with neck flexion or extension. The aim of this study was to use high-resolution MRI to determine the normal range of CXA in various neck positions using a reproducible measurement technique.
RESULTS: The mean CXA overall was 156.92degree (SD=4.23degree; range 134-179degree). The mean value for extension CXA was 169.20degree (SD=5.81degree), and the mean value for flexion CXA was 144.73degree (SD=5.71degree), the difference being statistically significant (p<0.0001) regardless of supine or prone position. Concordant correlations of reader measurements showed substantial agreement in the supine position at 0.96, with lower agreement in the prone position at 0.87.
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