MR volumetry of total intracranial and brain volume in normal adult population aged 40 years old and above

This study aimed to determine the total intracranial volume, total brain volume and total intracranial volume to total brain volume ratio among the male and female subjects in normal healthy subjects aged 40 years old and above. This was a retrospective study involving 58 subjects aged from 41 to 77 years old. The study was approved by the institutional review board. Magnetic resonance imaging of the brain performed using General Electric Signa Horizon LX 1.0 Tesla scanner. Magnetic resonance images were obtained in T1 sagittal and axial sections with 5-millimetre thickness with 2-millimetre gap. The images acquired were stored in the hospital’s Picture Archiving and Communications system and viewed using Osirix image viewer version 3.2.1. A single observer validated by an experienced neuroradiologist with more than 10 years’ experience performed volumetric analysis. Mean (SD) of total intracranial volume was 1397.06cm3 (132.51cm3) for all subjects. The mean total intracranial volume for male subjects was 1496.12cm3 (100.08cm3). For female subjects, the mean total intracranial volume was 1310.79cm3 (90.34cm3). The mean total brain volume for all subjects was 1245.29cm3 (125.34cm3). The mean total brain volume for the male subjects was 1338.05cm3 (91.96cm3). For the female subjects, the mean total brain volume was 1164.49cm3 (89.61cm3). Mean total brain to intracranial volume ratio for all subjects were 0.8911 (0.0245). Mean total brain to intracranial volume ratio for male subjects was 0.8946 (0.0276). Mean total brain volume to total intracranial volume ratio for female subjects was 0.8881 (0.0214). This study showed no significant difference in mean total intracranial volume, mean total brain volume and total brain volume to total intracranial volume ratio between male and female. However, the study obtained valuable normative data for estimation and predicting future degenerative events in our population.