Evaluation ofSupra and InfraTentorial Brain Anatomy Using Magnetic ResonanceImaging

Abstract

Many neuroanatomical studies of normal brain development have been reported. Investigations of aging effects on the supra and infra tentorial anatomical structures are important, not only to understand normal aging process, but also for comparative study of brain disorders. The study purpose to assess the sex differences and the age-related areas changes of both supra and infra tentorial anatomical structures on midsagittal MRIs. Midsagittal MRIs of 375 normal individuals were evaluated in this study by linear measurement of brainstem (midbrain, pons and medullaoblongata) and area measurements of infra tentorial anatomical structure including the posterior vermis, declive, folium, and tuber cenerium, anterior vermis and brainstem areas and the supra tentorium brain anatomy, the cerebrum area ,corpus callosum area (CC)and index have been evaluated for 100 cases of them in both genders. The sample included both genders, 206(54.9% were males) and 169(45.1% were females), their ages were between 1 - 91years old. Calculation of the linear measurements of brainstem and area of both supra and infra anatomical structures was performed and the collected data were statistically analyzed by using SPSS software, students' test was applied for gender comparisons. To determine the associations between age, gender and both regions, pearson correlation coefficients were calculated. No significant gender difference was recorded in the brain stem favoring midbrain (p=0.088) ,pons (p=0.940) and medulla oblongata(p=0.485). A-significant age-associated reduction in brain stem compartments was found at p=0.000 for mid brain, pons and medulla oblongata diameters. For infra tentorial anatomy significant sex difference was found in the mean anterior cerebellar at p= 0.006 favoring males with larger area than VI females whereas no significant difference was recorded in posterior cerebellar, (declive, folium and tuber) and brainstem at P=0.437, 0.825 and 0.552 respectively, significant reduction with increasing age were detected in means of declive, folium, and tuber, anterior vermis and brainstem at P=0.000, 0.004 , 0.000 respectively with no different in the posterior cerebellar at P=0.109 For the supra tentoruim brain anatomical structure; significant sex difference was found in the cerebrum area at P=0.001with no significant difference was recorded in the corpus callosum area and index at P=0.889 and 0.812 respectively, significant reduction with increasing age were detected in means of CC area and index at p=0.001 and 0.000 respectively with no different in the cerebrum at P=0.219. In the conclusion the study found that; the cerebrum and anterior cerebellar vermis were affected by gender while the corpus callosum area and index, brainstem, anterior cerebellar vermis and declive, folium, and tuber were affected by age. . The supra tentorial anatomical structures areas development are significantly correlated with infra anatomical structures.