磁共振表观弥散系数评估小鼠海马损伤程度的研究

A study on hippocampus injury assessment with apparent diffusion effect of MRI on mouse model

目的 通过测量磁共振表观弥散系数来客观分析早期海马区颅脑损伤小鼠模型的脑损伤程度.方法 选用健康成年雄性C57/BL6小鼠18只,采用随机数字表法分为对照组、脑损伤轻型组和脑损伤重型组,每组小鼠数量为6只,后两组分别于头颅打击后6h,12 h和24 h对各组小鼠进行头颅MRI检查、弥散加权成像（DWI）,选取海马作为兴趣区进行表观弥散系数（ADC）值的测量,比较兴趣区ADC值测量结果并进行统计学分析.结果 对照组两侧海马区ADC平均值分别为（8.65±0.26）×10^-4 mm2/s和（8.77±0.12） ×10^-4 mm2/s,二者比较差异无统计学意义（P＞0.05）.对照组、轻型组和重型组6 h ADC值分别为（8.70±0.50）×10^-4 mm2/s,（6.13±0.11）×10^-4 mm2/s和（3.16±0.78）×10^-4 mm2/s,12 h ADC值为（8.23±0.61）×10^-4 mm2/s,（5.92±0.27）×10^-4 mm2/s和（2.64±0.65）×10^-4 mm2/s; 24 h ADC值为（9.01 ±0.14）×10^-4mm2/s,（5.99±0.13）×10^-4 mm2/s和（2.58±0.42）×10^-4 mm2/s,三组间ADC值两两比较均差异有统计学意义（P＜0.05）.结论 不同类型海马区脑外伤小鼠的ADC值存在差异,可以此来鉴别脑外伤的损伤程度,同时早期发现颅脑损伤.

Objective To determine the utility of apparent diffusion coefficient （ADC） values as an objective method of early detection of traumatic brain injury of the mice models in hippocampus injury.Methods A total of 18 healthy male adult C57/BL6 mice were randomly divided into three groups according to the degree of injury：the mild group,severe group and control group.Conventional images,diffusion-weighted images,ADC were studied.The hippocampal were selected as the interesting area.ADC values were calculated and compared with those in control subjects after 6 h,12 h and 24 h.Student t test was performed for each region to compare the injury groups and the control.Results In control group both sides hippocampal ADC values had no differences（8.65±0.26 and 8.77±0.12） ×10^-4 mm2/s,P〉0.05.Abnormalities were detected on ADC values,compared with conventional images in the injury groups.ADC values in mild group and severe group were significantly different from those of control group（6 h ADC values were （8.70±0.50） ×10^-4 mm2/s,（6.13± 0.11） ×10^-4 mm2/s,and （3.16±0.78） ×10^-4 mm2/s in control,mild and severe group respectively）,（12 h ADC values （8.23±0.61）×10^-4 mm2/s,（5.92 ± 0.27） ×10^-4 mm2/s and （2.64±0.65） ×10^-4 mm2/s） and （24 h ADC values （9.01±0.14） ×10^-4 mm2/s,（5.99± 0.13）×10^-4 mm2/s and （2.58±0.42）×10^-4 mm2/s）,P〈0.05.Conclusion There are differences among the ADC values on differcnt types of hippocampal brain injury mouse-model.ADC values can identify the degree of damage on brain injury and can detect early craniocerebral injury.