应用^(18)F-DOPA PET显像诊断路易小体性痴呆

^(18)F-DOPA PET imaging in the diagnosis of dementia with Lewy bodies

目的 评价测定纹状体突触前多巴胺代谢水平对路易小体性痴呆 (DLB)诊断、鉴别诊断的价值。方法 研究对象分为 3组 :7例DLB患者 ,10例老年性痴呆 (AD)患者及 9例年龄相匹配的正常对照者。用18F fluorodopa(DOPA)PET显像测定受检者纹状体突触前多巴胺的摄取 (即脑内18F DOPA放射性水平 ,以流入速率常数Ki 表示 ) ,然后对 3组Ki 值进行比较。结果 ①DLB组Ki 值 (壳核 :0 0 0 6 4± 0 0 0 17,尾状核 :0 0 0 5 1± 0 0 0 19)明显低于AD组 (分别为 0 0 119± 0 0 0 2 1及 0 0 0 92±0 0 0 14)及对照组 (分别为 0 0 131± 0 0 0 2 8及 0 0 12 2± 0 0 0 35 ) ,差异均有显著性 (P均 <0 0 1) ;而AD组与对照组间的Ki 值差异无显著性 (P >0 0 5 )。②DLB的尾状核Ki 值 (正常值的 42 % )降低较壳核 (正常值的 49% )更为明显。③以Ki=0 0 0 6 2作为临界点 (正常尾状核 x - 2s) ,DLB与AD鉴别的灵敏度和特异性分别为 86 %和 10 0 %。结论 用18F DOPAPET显像检测多巴胺代谢功能有助于DLB的早期诊断和鉴别诊断。

Objective To assess validity of 18 F-fluorodopa (DOPA) PET imaging in diagnosis and differential diagnosis of dementia with Lewy bodies (DLB). Methods The study population consisted of 7 DLB and 10 Alzheimer's disease (AD) patients as well as 9 age-matched normal subjects. By using 18 F-DOPA PET we measured the activity of 18 F-DOPA in individual putamen and caudatum to represent striatal pre-synaptic dopamine uptake. A mean influx constant ( K _i) was applied to compare the mean activity of 18 F-DOPA among three groups. Results ①Dopamine uptake expressed as mean K _i in DLB (putamen:0.006 4±0.001 7 and caudatum:0.005 1±0.001 9 respectively) was significantly reduced compared to that in AD(0.011 9±0.002 1 and 0.009 2±0.001 4) and normal controls(0.013 1±0.002 8 and 0.012 2±0.003 5, P <0.01),whereas there was no difference between the uptakes of AD and normal controls( P >0.05). ②In DLB, K _i reduced more in the caudatum (42% of normal) than in the putamen(49% of normal).③Using a constant 0.006 2 as cut-off point(mean K _i in caudatum of normal-2 s ), DLB was distinguished from AD with a sensitivity of 86% and a specificity of 100%. Conclusion Assessment of striatal dopaminergic function with 18 F-DOPA PET may be an informative diagnostic adjunct for DLB at early stage.