Age-Related Changes in Signal Intensity Ratio of Normal Clivus Bone Marrow on Magnetic Resonance Imaging

Objective: To evaluate the association between the signal intensity ratio of clivus bone displayed on magnetic resonance (MR) imaging and ages. Materials and Methods: A retrospective cohort study of 268 patients underwent brain MR imaging during January 2015 to October 2019. We qualitatively and quantitatively assessed bone marrow signal intensity of clivus bone that were performed on T1-weighted sagittal images. In qualitative assessment, the signal intensities of clivus were visually graded from Grade I to III according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, we evaluated the association between the signal intensity ratio of clivus to pons and age categorized by decades in multivariable Gaussian regression analysis. Results: Of 268 patients, the ratio of males to females is 1:1. Grade I clivus was found about 35% of the age 1-9 years, whereas Grade 3 clivus was more frequent (more than 13%) in the ages over 30 years. There were statistically different in the mean values of clivus/CSF and clivus/pons signal intensity ratios by grades. The mean values of clivus/CSF and clivus/pons signal intensity ratios were increased by ages in both sexes, but slightly higher in males. In regression analysis after adjustment for sex, the differences in mean values of clivus/pons signal intensity ratios were larger by increasing age, using the age 1-9 as a reference group. Conclusion: The present study confirms that signal intensity ratios of clivus to pons on T1-weighted sagittal MR images is increased with ages.