Thickness of cerebral cortex measured using anatomical mesoscopic imaging and magnetic resonance imaging

Magnetic resonance imaging method opened up the possibility for in vivo examination of the anatomy of human brain. For this reason it is interesting and relevant to compare the knowledge accumulated over a number of years during the examination of the composition of dead brain to that obtained from magnetic resonance images. The aim of this study was to determine and compare the thickness of cerebral cortex in human of different age and sex, measured in different sites of the hemispheres when applying anatomical mesoscopic imaging and magnetic resonance imaging. The thickness of cerebral cortex was measured in symmetrical Brodmann's areas of both hemispheres. The anatomical mesoscopic imaging technique was used for the examination of 2x2-cm cortex samples obtained during autopsy and fixed for 4 weeks in 10% paraformaldehyde. In these samples, cortex thickness was measured in sections perpendicular to the convolution, using an operative microscope, in a mesoscopic image at x16 magnification and with an accuracy of 0.01 mm. Using cerebral magnetic resonance imaging, the thickness of cerebral cortex in live subjects was measured on T1-weighted images of patients examined at the Clinic of Radiology, Kaunas University of Medicine Hospital. The measured cortical field image was magnified to the smallest element of digital image - the pixel - and measured with an accuracy of 0.01 mm. Each of the two techniques was applied for the examination of 20 men and women who were divided into age groups of 20-60 years (n=10) and older than 60 years (n=10). Both examination methods yielded a statistically significant difference in the thickness of cerebral cortex between Brodmann's areas 1, 4, and 19. No significant difference in cortex thickness was found between different age and sex groups; however, the findings showed that the difference in cortex thickness between the different age male groups was 4.6% and female - 1.6%. No significant difference using different techniques was found, but the cortex thickness in the fixed samples was reduced by 0.5 cm on average.