摘要
目的 探讨Alzheimer病 (AD)模型大鼠脑MRI信号变化 ,为AD早期诊断提供特征性MRI指标。方法 在脑立体定位仪上切断一侧穹窿海马伞建立AD动物模型。经Morris水迷宫行为学检测确定模型成功后 ,用MRI作脑冠状面T1加权像 (T1 WI)、T2 加权像 (T2 WI)和扩散加权像 (D WI)研究。结果 T2 WI显示部分动物双侧海马、侧脑室信号增强 ,其信号强度由中线 (CA1区 )向外侧 (CA3区 )逐渐减弱 ,该区T1、T2 弛豫时间延长 ,扩散系数增大。侧脑室中央部及其下角呈现轻度扩大 ,手术侧尤为明显。第三脑室也有轻度扩大。隔区有“斑点状”散在增强信号。海马、内嗅区以及新皮质未见明显萎缩。其它脑区未见明显异常改变。结论 切断穹窿海马伞可引起动物学习记忆障碍。动物脑MRI呈现特征性改变 ,海马和侧脑室信号增强 ,尤以CA1区最明显。本文认为这些改变可作为AD早期诊断的特异性MRI指标。
Objective To explore brain MRI signal changes of rat model of Alzheimers disease. Methods The model was made by transecting unilateral fimbria fornix on stereotaxic devisor and proved successfully by Morris water maze. The MRI experiments were performed on a 30cm bore 4.7T superconductor MR scanner(T 1 weighted MRI,T 2 weighted MRI and Diffusion weighted MRI). Results T 2 weighted images showed hyperintensity on the bilateral hippocampus and lateral ventricles in some experimental rats. The T 2 WI intensity was decreased from CA 1 area to CA 3 area of hippocampus. T 1 and T 2 time increased along with the increment of apparent diffusion coefficient(ADC). Enlargement in lateral ventricles and the third ventricl were doserved by T 2 WI.There were also hyperintensity at septal area,but no abnormal signal changes had been found on neocortex and entorhinal cortex,where there were also no atrophic changes. Conclusion Fimbria fornix transection lesion can results in rats learning and memory disorder. There are abnormal MRI signal changes on the bilateral hippocampus and lateral ventricles as wall as septal area,which are the characteristic markers of early diagnosis of Alzheimers disease.
出处
《解剖学研究》
CAS
2001年第1期28-31,共4页
Anatomy Research
