Study On The Structure And Glucose Metabolism Of Cynomolgus Monkey Brain Based On The PET/MR Template

PurposeBased on the PET/MR template of monkey brain,the quantitative analysis of the brain volume and glucose metabolism of cynomolgus monkeys at different ages was carried out to study the changes of the brain volume and glucose metabolism level at different life stages,so as providing data reference for non-human primate brain research.Methods115 healthy cynomolgus monkeys were divided into juvenile group?n=29,1.7±0.5y?,youth group?n=33,3.5±0.6y?,adult group?n=35,13.9±3.7y?and elderly group?n=18,22.8±1.2y?.PET/CT-MRI?3.0T??GE Discovery Milwaukee,GE Discovery Elite,USA?equipment was used to image all cynomolgus monkeys,and 3D Bravo T1 sequence image data and resting state ¹⁸F-FDG PET/CT image data of brain were collected.In SPM12?Statistical parametric mapping,SPM?platform,based on the PET/MR template"HJT",the MRI structure images and ¹⁸F-FDG PET glucose metabolism images of cynomolgus monkey brain will be space standardized.The"HJT"brain atlas was used to segment the brain tissue,and 44 bilateral brain functional regions were divided,and the image intensity value of each region was extracted.The absolute value of total brain volume?TBV?were calculated according to the image resolution,and the Regional brain volume ratio?RBVr?of each functional brain region was calculated with individual TBV as the reference,and the Standard uptake value ratio?SUVr?of each functional brain region was calculated with the pons as the reference.The subdivisions of some functional brain regions were combined and 33 bilateral functional brain regions were selected.SPSS?Statistical Product and Service Solutions?and Graphpad Prism software were used for Statistical analysis.Age-related changes and unilateral asymmetry of total brain volume,functional area volume ratio and glucose standard uptake ratio of cynomolgus monkeys in juvenile,youth,adult and elderly groups were analyzed.Sex differences in total brain volume,functional area volume ratio and standard glucose uptake ratio of cynomolgus monkeys in juvenile,youth and adult groups were analyzed.Results1.The combination of PET/MR imaging technology and monkey brain template tool had obtained high-quality images of monkey brain structure and glucose metabolism.Based on the brain template,image space standardization and brain tissue segmentation had been completed,and accurate positioning of brain structure and accurate quantification of brain volume and glucose metabolism have been achieved.2.The peak of total brain volume of cynomolgus monkeys appeared in the adult period,and the growth curve was a parabolic curve rising first and then falling.There were different developmental trajectories in the volumes of functional brain areas in different age groups.There were significant age differences in the volume ratios of auditory cortex,pallidum and other functional brain areas?p<0.05?,while no significant correlation was found in the rest?p>0.05?.The left side of the cerebellum,cingulate,motor area and pons have bigger volume in all ages?p<0.05?.The volume of auditory cortex,hippocampus,and other brain regions have no significant lateral differences in adolescence to adulthood?p>0.05?,but characterized by larger on the right in old age?p<0.05?.The rest of the brain functional areas have no obvious age-related volume differences?p>0.05?.From adolescence to adulthood,there was no significant difference in the total brain volume between male and female cynomolgus monkeys?p>0.05?.As individuals TBV as a reference for normalization after calculation,the volume ratio of various brain regions has not significant difference.The cerebellum,cingulate gyrus and so on a number of brain regions in adolescence and young adulthood showed a significant gender difference?p<0.05?,all brain regions volume ratio has no significant gender difference after adulthood?p>0.05?.3.In different age groups,there were significant differences in glucose metabolism patterns of all functional brain regions,and glucose metabolism level in all functional brain regions continued to decrease from juvenile to old age?p<0.05?.The right side of the olfactory and piriform cortex have higher level of glucose metabolism in all ages?p<0.05?,the right side of the auditory cortex,dentate,hippocampus and other brain regions have higher level of glucose metabolism in juvenile period?p<0.05?,but has no obvious difference in youth to old age?p>0.05?,the glucose metabolism level of the others have no obvious difference?p>0.05?.The glucose metabolism level between male and female cynomolgus have no significant difference in juvenile and youth period?p>0.05?,but in adulthood,sex differences was found in some functional areas of the brain,such as the screen-shaped nucleus and the motor area.ConclusionBased on PET/MR template of monkey brain,the precise positioning of PET/MR images of cynomolgus monkey can accurately quantify the changes in the brain volume and glucose metabolism at all ages.The study of the changes in the volume and glucose metabolism of the total brain and functional areas of the cynomolgus monkeys at all ages will enhance the understanding of the dynamic growth process of the cynomolgus monkey brain and enrich the research results of non-human primate brain science.