轻度认知功能障碍和轻度Alzheimer病的^1H—MRS研究

Brain proton magnetic resonance spectroscopy in mild cognitive impairment and mild Alzheimer disease

目的探讨质子磁共振波谱(1H-MRS)对轻度认知功能障碍(MCI)和轻度Alzheimer病(AD)的诊断和鉴别诊断的作用。方法采用刺激回波序列(STEAM),对30例MCI患者、30例轻度AD患者和30例性别、年龄、文化程度匹配健康对照的双侧内侧颞叶1H-MRS进行分析,比较各组间N-乙酰天门冬氨酸/肌酸(NAA/Cr)、胆碱/肌酸(Cho/Cr)和肌醇/肌酸(MI/Cr)、N-乙酰天门冬氨酸/肌醇(NAA/MI)比值及不对称指数的差别,并对MCI和轻度AD组的简易智能精神状态量表(MMSE)评分与NAA/Cr、Cho/Cr、MI/Cr、NAA/MI进行相关分析。结果MCI组的左侧NAA/Cr及轻度AD组的两侧NAA/Cr显著低于对照组(P<0.05),MCI组和轻度AD组的两侧NAA/Cr无显著差异(P>0.05)。三组间的Cho/Cr无差异(P>0.05)。MCI组和轻度AD组的两侧MI/Cr显著高于对照组(P<0.05),MCI组和轻度AD组的左侧MI/Cr有显著差异(P<0.05)。MCI组和轻度AD组的两侧NAA/MI显著低于对照组(P<0.05),MCI组和轻度AD组的左侧NAA/MI有显著差异(P<0.05)。MCI、轻度AD和对照组的NAA/Cr、MI/Cr、NAA/MI有一定的左侧偏性,但三组之间的代谢物不对称指数无显著差异(P>0.05)。MCI和轻度AD两组的MMSE评分与两侧NAA/Cr明显正相关(P<0.05)。轻度AD组的MMSE评分与右NAA/MI明显正相关(P<0.05)。两组合并的MMSE评分与左NAA/Cr、MI/Cr、NAA/MI明显正相关(P<0.05)。结论MCI、轻度AD患者内侧颞叶NAA/Cr、NAA/MI比值的降低与MI/Cr比值的升高,以及MCI和轻度AD患者的左侧MI/Cr、NAA/MI有显著差异,为MCI和AD的早期诊断和鉴别诊断提供参考。MCI和轻度AD患者NAA/Cr、NAA/MI的变化与痴呆严重程度的相关性,对MCI和AD的疾病进展和治疗监测有重要作用。1H-MRS是MCI和AD的诊断、鉴别诊断和疾病监测的有用工具。

Objective To evaluate the roles of proton magnetic resonance spectroscopy （^1H-MRS）in the diagnosis and the differential diagnosis of mild cognitive impairment （MCI） and mild Alzheimer disease （AD）. Methods A ^1H-MRS was performed in the bilateral medial temporal lobes（MTLS） of 30 MCI patients,30 mild AD patients and 30 healthy age and sex-matched controls with use of stimulates echo acquisition mode（STEAM）. The ratios of NAAICr,CholCr,MI/Cr,NAA/MI and metabolite asymmetries were compared among the groups. Correlation coefficients were calculated for Mini Mental State Examination （MMSE） scores and the ratios of NAA/Cr,CholCr,MI/Cr and NAA/MI in the MCI group and the mild AD group. Results Patients with mild AD showed significant reduction of NAA/Cr, NAA/MI ratios in the bilateral MTLS ,and significant MI/Cr increase in the bilateral MTLS relative to control subjects. Patients with MCI demonstrates significant reduction of NAA/Cr in the left MTL, significant reduction of NAA/MI ratio and significant MI/Cr increase in the bilateral MTLS relative to control subjects. Patients with mild AD showed statistical differences of MI/Cr and NAA/MI ratios in the left MTL relative to patients with MCI .The Cho/Cr ratios among the three groups showed no significant differences. Metabolite asymmetries were seen, but no statistical differences among the three groups. Patients with mild AD and MCI showed significant correlation between MMSE and NAA/Cr ratio. Patients with mild AD showed significant correlation between MMSE and right NAA/MI ratio. Patients with cognitive dysfunction showed a significant correlation between MMSE and left NAA/Cr,MI/Cr,NAA/MI ratios. Conclusion The reduction of NAA/Cr and NAA/MI ratios and the MI/Cr ratio increase in the bilateral MTLS in patients with mild AD and MCI, and patients with mild AD showed statistical differences of MI/Cr and NAA/MI ratios in the left MTL relative to patients with MCI, which seem to be useful for the diagnosis and the differential diagnosis of mild AD and MCI. The changes of NAA/Cr, NAA/MI ratios in patients with mild AD and MCI showed correlation to its severity, which is important for the process of cognitive dysfunction and the therapy monitor. ^1H-MRS has an important effect on the diagnosis and the differential diagnosis of cognitive dysfunction and its progression.