CEST成像不同量化方式在急性帕金森氏病小鼠模型研究中的应用比较

本文通过比较7 T场强下化学交换饱和转移（chemical exchange saturation transfer，CEST）成像技术不同量化方式在急性帕金森氏病小鼠模型研究中的应用效果，探讨了客观无创的帕金森氏病研究方案.使用Bruker PharmaScan 7 T小动物磁共振成像（Magnetic Resonance Imaging，MRI）扫描仪，对经1-甲基-4-苯基-1，2，3，6-四氢吡啶（1-methyl-4-phenyl-1，2，3，6-tetrahydropyridine，MPTP）急性造模前及造模后第3、10天的小鼠黑质、皮层及海马进行扫描，计算弛豫时间T₁、T₂、MTR_asym（magnetization transfer ratio based on asymmetry analysis）、MTR_rex（magnetization transfer ratio yielding Rex）、AREX（apparent exchange-dependent relaxation）及5池拟合后的胺峰面积Area_amine、酰胺峰面积Area_amide.结果显示仅黑质中融合了倒Z谱分析和5池洛仑兹拟合所得的量化指标MTR_rex、AREX及Area_amine在造模后显著减小，与黑质免疫组化结果一致，而T₁、T₂以及基于Z谱非对称性分析的MTR_asym未见统计学差异，这表明此量化方式消除了直接饱和效应及磁化转移效应的影响，准确性上要优于Z谱非对称分析法，更能正确地提示帕金森氏病黑质的变化.

Comparisons of Different CEST Quantification Metrics Applied in Acute Parkinson's Disease Mouse Model

Non-invasive and quantifiable diagnosis of Parkinson's disease (PD) is an ongoing challenge for researchers. In this study, we compared two different chemical exchange saturation transfer (CEST) imaging quantification metrics in substantia nigra (SN), cortex and hippocampus of acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice at three different time points including before MPTP administration, and the 3^rd and 10^th day after MPTP administration. Area of amine (Area_amine), magnetization transfer ratio yielding R_ex (MTR_rex) and apparent exchange-dependent relaxation (AREX) in SN derived from 5-pool Lorentzian fitting and inverse Z-spectrum analysis showed a statistically significant decrease after successful modeling, while there were no significant alterations in T₁, T₂, and magnetization transfer ratio based on asymmetry analysis (MTR_asym). The results suggested that the former quantification is superior to that based on Z-spectrum asymmetry in vivo due to the exclusion of direct saturation (DS) and magnetic transfer (MT) effects and may reflect the destroying SN of PD.