The importance of volume and area fractions of cerebellar volume and vermian subregion areas: a stereological study on MR images

Abstract

Purpose: Age, gender, and body size are important factors which are affecting the cerebellar volume (CV). Many neurological diseases lead changes in CV. The aim of this study is to measure CV and the total intracranial volume (TIV) for both genders on magnetic resonance images (MRI), to calculate the CV/TIV volume fraction, and also to determine the normal values that can be regarded clinically significant by determining the total vermis area and vermian subregion areas (V1, V2, and V3).

Methods: In this retrospective study, MR images (without any pathological findings) of 200 individuals (100 female, 100 male) between the ages of 20-40 were used. CV and CV/TIV volume fractions, vermian subregion areas, and area fractions were calculated by using the Stereoinvestigator 8.0 (Microbrightfield, USA) software. The volumetric calculations were performed by the point counting method according to the Cavalieri principle, which is one of the volume calculation methods in stereology. Total CV, TIV, cerebellar vermis areas (V1, V2, and V3), and total cerebellum area were measured separately for both groups.

Results: The volume of cerebellum was 120.53 ± 11.1 cm³ in males, 105.99 ± 11.2 cm³ in females, TIV was 1304.99 ± 91.7 cm³ in males and 1155.15 ± 85.7 cm³ in females. CV and TIV were statistically higher in males (p = 0.001, p = 0.001 respectively). It was observed that the differences between the genders in terms of CV/TIV disappeared (p = 0.679). The total vermis area was 11.59 ± 1.3 cm² in males and 10.85 ± 1.3 cm² in females. V1 area, V3 area, and the total vermis area were found statistically higher in males (p = 0.05, p = 0.006, p = 0.007 respectively). It was determined that the area fraction of V2 was higher in females when the fractions of V1, V2, and V3 to the total vermis area were examined (p = 0.03).

Conclusion: We believe that the normal values of CV, TIV, and vermian subregion areas, determined by stereological method, will contribute to the diagnosis and the treatment plan of the clinical pathological evaluations in adults and children.

Keywords: Cavalieri principle; Cerebellar vermis area; Cerebellum volume; Stereology.