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

Objective. 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. Material and methods. 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 2×2-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 ×16 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). Results and conclusions. 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

The Center of the human porta hepatis

Majority of interventional procedures are made at the porta hepatis, which has a different location on the visceral surface of the liver. Objective. To describe the location of the porta hepatis in respect of the borders of the visceral surface and separate lobes of the liver. Material and methods. Sixty-four human livers were obtained at autopsy (mean age, 45 years). We chose the point of the crossing of longitudinal and transversal lines of the porta hepatis, which was considered as center of the porta hepatis. The distances from the center of the porta hepatis to the border of the visceral surface every 10 degrees with protractor and ruler and the angles of anatomical structures were measured. Additionally, the borders of lobes were assessed. Results. We found that center of the porta hepatis is located approximately 11.6±2.8 cm from the border of the visceral liver surface. The location of center of the porta hepatis was 11.6±1.1 cm from the border of left lobe, 9.7±1.5 cm from the border of quadrate lobe, 12.3±1.2 cm from the border of right lobe, and 7.4±1.0 cm from the border of caudate lobe. All distances were statistically significant (P<0.05). An angle of the fissure for round ligament was 50.5°, of the fossa of gallbladder – 102°, of the groove of vena cava inferior – 266°, and of the fissure for ligamentum venosum – 293°. The borders of the right, left, quadrate, and caudate liver lobe covered 45.6%, 32.6%, 14.3%, and 7.5% of the perimeter of visceral surface border, respectively. Conclusions. The center of the porta hepatis can help to characterize precisely the position of the porta hepatis on the visceral surface of the liver