| Objective:Hippocampus,correlated to learning and study,is an important structure of limbic systems,and its volumes and shapes can be affected by many psychosis.The subdivisions of hippocampus are confused,and it is hard to identify its boundary from surrounding structures.In this study,we choosed the landmarks with invariableness and easy identification which can be accepted by most scholastics.We can provided the normal volume of hippocampus and its subregion by MRI measurement and basement of pathogenesis of depression disorder by investigating hippocampal volume and shape characteristics of the depression.Method:Subjects:The first part consist of 30 normal youth(male 15,female 15) and 30 old people(male 15,female 15).The second part consist of 30 adult female depressions and 30 normal adult females. Using Siemens 3.0T MR,the head was made scanning in inclined coronal position.By Siemens imaging workstation,the gained images were reconstructed with axial and sagital plane.2.The hippocampus of each layer was segmented by the landmarks with invariableness and easy identificated one by one and gained areas of each slice in the imaging of inclined coronal plane and the head,body and tail of the hippocampus were divided by the landmarks.The areas of each layer were added one by one and were multiplied to slice thick and obtained the raw volume of the hippocampus and subregions.In order to avoid the influences of cranial volumes,we treated raw volume with some methods and the normalized volumes of the hippocampus were gained.3.The normalized hippocampal volumes were compared by SPSS13.0 and we can obtain changes characteristics of hippocampal volumes in different age and depression.Using three-dimensional imaging processing software Mimics12.0 invented by Belgian's company,the 2D DICOM images were imported,we can obtain three-dimensional images and analyse the shape characteristics of the hippocampus.Result:1.The hippocampus boundary and its anatomy marks can be displaied clearly in MRI.Uncal recess of inferior horn of lateral ventricle as the boundary sign of hippocampal head and amygdale,were displayied 98.3 percent.Alveus played an important effect in dividing hippocampal volumes and its display rate was 98.3 percent.As mark of artificial,the triangle of lateral ventricle's display rate was 100 percent,and can discriminate hippocampal head and amygdale.As the boundary of head and body,uncal apex's display rate was 94.8 percent.Full views of fornix was used as the boundary of body and tail and its display rate was 98.5 percent.2.The volumes of normal adult:youth group:right hippocampus was 3326.8±359.2 mm~3 and left hippocampus 3304.1±383.7mm~3 and right head 1844.3±318.9mm~3 and left head 1836.2±587.5mm~3;right body 980.6±176.5mm~3,left body 969.2±134.4mm~3;right tail 501.1±121.3mm~3, left tail 498.0±133.7mm~3.The older age-group:right hippocampus 1432.2±171.4mm~3,left hippocampus 1313.1±162.6mm~3;right head 716.7±115.8mm~3,left head 659.6±109.1mm~3;right body 474.3±94.7mm~3, left body 472.4±92.5mm~3;right tail 240.5±75.3mm~3,left tail 180.6±72.9mm~3.3.There were no significant difference between male's volumes and female's volumes.In older age-group,the volumes of right hippocampal tail were bigger than left's.The numerical values of right hippocampal volumes were bigger than left's,and very near statistical significance. The whole and each parts of hippocampal volumes of older age-group were obviously smaller than youth group's,especial the hippocampal head.The whole and each parts of hippocampal scan slices of older age-group were less than youth group's,which indicated that long axis of older age-group's hippocampus was short.Besides,the average areas of both sides hippocampal head volumes of older age-group were smaller than youth group's,which indicated that hippocampal head became short and narrow.4.The depression group:right hippocampus was 3205.3±259.6 mm~3,left hippocampus 3164.4±281.2 mm~3;right head 1799.5±331.8mm~3, left head 1817.4±301.2mm~3;right body 991.4±187.1 mm~3,left body 958.0±149.3mm~3;right tail 413.7±101.3mm~3,left tail 384.54±119.6mm~3. Control group:right hippocampus 3324.6±358.3mm~3,left hippocampus 3303.8±382.6 mm~3;right head 1842.4±316.8mm~3,left head 1833.2±588. 7mm~3;right body 979.6±175.6mm~3,left body 970.1±133.9mm~3;right tail 499.8±120.8mm~3,left tail 497.9±133.0mm~3.5.The volumes of the hippocampus and its tail of the depression group were obviously smaller.There were no variances of hippocampal head and body in depression group.The average areas of hippocampal head of control group were bigger than depression group's,but the numbers of slices were smaller;the numbers of slices of hippocampal tail of depression were smaller than control group.6.The analysis results which came from statisticsing areas and slices were proved by the 3-D reconstruction model.Conclusion:1.The anatomic landmarks of identification the hippocampal from other structures and its subregions were repeatability which made standardized measure of hippocampus become possible.2.There were no significant difference between male and female in hippocampal volumes of normal subjects.The hippocampal tail of older age-group was shrinked on the left.There were significant difference between elder and youth and as the ages growing,the volumes of hippocampus became small,especially hippocampal head,which became short and narrow. 3.It was the characteristics of the depression that the volumes of the hippocampal tail became smaller and the hippocampal shapes were also changed.
|
PDF Full Text Request