Abstract:

Objective To discuss the feasibility  of magnetic resonance imaging
 in measurement of hippocampal formation volume in  fixed brain  area,and to provide relevant data for research on  neurodegenerative diseases.   Methods
68 cases of adult volunteers from China-Japan Union Hospital of Jilin University were selected (33 males and 35 females). The brains of subjects were scaned using  3D-fSPGR sequence. 10 sagittal images were aquired equally in the area between the bilateral lateral margin of the fourt
h ventricle   and corresponding lateral border of vitreous body. After the outlines of the hippocampal formation were drawed,the volumes of hippocampus were calc
ulated by multiplying by the thickness between two slides and then corrected by cranial cavity volume. The correlations including hippocampal formation

volume and cavity volume,hippocampal formation volume and ages or gender were studied. The data were analyzed by using  SPSS 17.0 software. 
Results  No significant differences were found between the volumes of hippocampal formation and ages (P>0.05) or genders (P>0.05). Significant differences were found between the right and lefe hippocampal formation(before correction: t=2.091,P<0.05;after correction: t=2.032，P<0.05). Significant difference in the volume of hippocampal formation between before and after correction only existed in female group(left：t=－2.092，P<0.05；right：t=－2.100，P<0.05). According to our
 data,the average volumes of left and right hippocampal formations in adults were (2 649.92－2　903.17)　mm3 and (　2579.42－2　803.27)　mm3，respectively. Conclusion Magnetic resonance imaging  measurement of hoppocampal formation by ten equal sagittal planes,from the lateral border the of fourth ventricle and the lateral border of vitreous body,could standardize the measurement of hippocampus.

Key words: hippocampal formation, volume, magnetic resonance imaging, sagittal plane