Cranio-vertebral transition assessment by magnetic resonance imaging in a sample of a northeast Brazilian population.

Platybasia and basilar invagination are important alterations of the cranial-vertebral transition. Neuroimaging-based platybasia parameters include the Welcker basal angle, distance between the apex of the odontoid and Chamberlain's line, and the clivus-canal angle. This study aimed to measure and correlate these parameters in a sample from northeast Brazil. Methods: Cross-sectional analysis of craniometric parameters from individuals submitted to magnetic resonance at an outpatient imaging center between 2011 and 2012. Results: Of 181 analyzed cases, the Welcker basal angle averaged 128.96 degrees (SD 6.51), median distance between apex of the odontoid and Chamberlain's line was 2.27 mm (IQR-1.23-4.47) and the median clivus-canal angle was 150.5 degrees (IQR 143.2-157.3). The Welcker basal angle was inversely correlated to the clivus-canal angle, and correlated to the distance between the apex of the odontoid and Chamberlain's Line. Conclusion: There was a tendency to platibasia, basilar invagination and narrowing of the cranio-vertebral transition.