Objective: To assess whether the signal intensity ratio of the clivus to corpus callosum (clivus/CC) depends on age.

Materials and Methods: A retrospective study of 244 subjects investigated the magnetic resonance imaging (MRI) appearance of the clivus on T1-weighted sagittal images. Both qualitative and quantitative assessments of MRIs were evaluated. In qualitative assessment, signal intensity patterns of clivus were graded from I to III, according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, the authors performed multivariable Gaussian regression analysis to assess the association of age categorized by decades and the signal intensity ratio of clivus/CC and clivus to cerebrospinal fluid (clivus/CSF).

Results: Grade I clivus was found in about 40% of the age 1 to 9, whereas Grade III clivus was more frequent at more than 15% in the age over 50. There were statistically different in the mean values of clivus/CSF and clivus/CC signal intensity ratios by grades. The mean values of clivus/CSF and clivus/CC signal intensity ratios were increased by ages in both genders, but slightly higher in males. In unadjusted analyses, the differences in mean values of clivus/CC signal intensity ratio were larger by increasing age. After adjustment for gender, the difference in mean values remained the same.

Conclusion: There was an age-related pattern of clivus bone marrow intensity. Since the use of CC as a new landmark showed a similar pattern as of pons, the ratio of clivus/CC signal intensity may be used as an alternative measurement in brain MRI.

Keywords: Clivus; Bone marrow; Magnetic resonance imaging (MRI); Corpus callosum (CC)

DOI: 10.35755/jmedassocthai.2022.10.13672

Received 17 May 2022 | Revised 22 August 2022 | Accepted 1 September 2022