Magnetic Resonance Imaging (MRI) Protocol
Three experienced Neuroradiologists who are blinded to patients’ data reviewed the MR images (1.5 T; Siemens, Magnetom-Avantou, Germany) of all patients in the study, and 10 measurements other than TH were obtained from this study. On repeated tests, high intraobserver reliability was demonstrated (with 95 percent confidence intervals) in 20 randomly selected situations. Both the CM-I (n=100) and control (n=100) groups were evaluated regarding the axial, sagittal and coronal T1 and T2 weighted MRIs. The measurements were obtained manually from the mid-sagittal images. These measurements consisted of; F1: Tonsillar herniation; F2: Distance from the pons to FM; F3: Distance from corpus callosum to FM; F4: Distance from Fastigium to FM; F5: Distance from the pons to dens axis; F6: Distance from corpus callosum to dens axis; F7: Distance from Fastigum to dens axis; F8: Distance from dorsum sella to dens axis; F9: Clivus length; F10: Distance from dens axis to posterior margin of FM; F11: Clivus canal angle (Weckenheim line- posterior vertebral body line) (Figure 1).