轻度阿尔茨海默病海马各区磁共振T_2信号的研究

MRI-T_2 signals in hippocampus of patients with mild Alzheimer's disease

目的探讨轻度阿尔茨海默病(AD)患者左右侧海马头体尾各部磁共振T2信号强度的变化,为AD的临床早期诊断及早期治疗提供影像学帮助。方法选择轻度AD患者(轻度AD组)20例和老年健康体检者(对照组)20例。所有受试者均行快速自旋回波T2序列,并在工作站手工勾绘海马各部感兴趣区,测量其T2信号强度。并分析各部磁共振T2信号强度与简易智能状态检查量表(MMSE)评分的相关性。应用ROC曲线计算海马磁共振T2信号作为轻度AD临床诊断指标的阈值,并评价其价值。结果轻度AD组双侧海马头部磁共振T2信号强度较对照组明显增高,差异有统计学意义(P<0.05)。MMSE评分与轻度AD双侧海马头部呈负相关。左侧海马头部磁共振T2信号强度最佳诊断阈值为563.0,敏感性为87.0%,特异性为94.0%;右侧海马头部磁共振T2信号强度最佳诊断阈值为562.2,敏感性为89.0%,特异性为93.0%。结论轻度AD患者双侧海马头部磁共振T2信号强度存在异常,并可作为AD早期诊断有价值的辅助指标之一。

Objective To provide the evidence for early diagnosis and treatment of Alzheimer＇s disease（AD）by studying the MRI-T2 signals in left and right hippocampal head and tail of AD patients. Methods Twenty mild AD patients served as a mild AD group and 20 elderly subjects served as a control group and underwent FSE-T2 sequencing. The MRI-T2 signal intensity was measured at the margin of manual-outlined hippocampal subfields. The relation between MRI-T2 signal intensity and MMSE score in hippocampal subfields was analyzed. The MRI-T2 signals in hippocampal head and tail were calcuiated according to the ROC curve and used as a threshold value for the early diagnosis of mild AD. Results The MRI-T2 signal intensity in bilateral hippocampal head was significantly higher in mild AD group than in control group（P〈0.05）. The MMSE score was negatively related with the hippocampal MRI-T2 signal intensity. The best threshold value of MRI-T2 signal intensity in the left and right hippocampal head was 563.0 with a sensitivi- ty of 87.0% and a specificity of 94.0% ,and 562.2 with a sensitivity of 89.0% and a specificity of 93.0%. Conclusion Abnormal MRI-T2 signal intensity exists in bilateral hippocampal head and can be used as an auxiiliary marker in early diagnosis of AD.