阿尔茨海默病^(18)F-FDDNP PET显像初步临床应用

Imaging of beta-amyloid plaques in vivo with ^(18)F-FDDNP

目的探讨2-(1-{6-[(2-^(18)F-乙基)(甲基)氨]-2-萘}-乙叉)-丙二腈(^(18)F-FDDNP)PET显像条件及用于阿尔茨海默病(AD)诊断的价值。方法 7例 AD(AD 组),6例血管性痴呆(VD 组)患者及6名智力正常老年对照者(HC 组)。静脉注射^(18)F-FDDNP 后 HC 组中的3例采用连续动态采集程序扫描并生成时间-放射性曲线,余受试者在药物注射后5,25和45 min 分别采集图像。采用ROI 法进行图像分析,计算3组受试者各脑区在5～75 min 及5～45 min 的放射性清除率并进行统计分析。结果 ^(18)F-FDDNP 能快速通过血脑屏障且之后能很快从健康脑组织中洗脱。AD 患者脑内放射性清除较 HC 组慢,而 VD 患者 PET 显像与 HC 组差别不大。AD 组大脑皮质及皮质下核团放射性清除率与 HC 组比较,差异有统计学意义(P<0.05),而白质和小脑差异无统计学意义。VD 患者与HC 组比较,除纹状体外各脑区放射性清除率差别无统计学意义。结论 ^(18)F-FDDNP 符合神经系统显像剂的要求。^(18)F-FDDNP PET 脑显像能有效诊断 AD,且可以鉴别 AD 和 VD。

Objective Alzheimer disease （AD） is the most common form of dementia. The hallmark pathological features of AD include amyloid senile plaques （APs） and neurofibrillary tangles （NFTs）. This study was designed to determine the localization and load of APs and NFTs in the brains of AD patients, and to evaluate the diagnostic value of 18^F-2- （ 1- { 6- [ （2-18^F-fluoroethyl） （methyl） amino ] -2-naphthyl} ethylidene） malononitrile （FDDNP） PET in differentiating AD from vascular dementia （VD）. Methods Nineteen subjects were divided into three groups： 7 AD patients, 6 VD patients and 6 normal control （HC） subjects. Sequential dynamic emission scans were obtained in 3 AD patients immediately after 18^F-FDDNP administration. All other subjects had emission scans obtained at 5, 25 and 45 min after 18^F-FDDNP administration. The PET results were analyzed by visual inspection and by ROI quantification. The ratios of radioactivity clearance defined by the ROI brain regions from 5 to 25 min and from 5 to 45 rain after 18^F-FDDNP administration were calculated. Results 18^F-FDDNP crossed and cleared from the blood brain barrier very rapidly. Visual and ROI methods found that AD patients typically showed marked retention of 18^F-FDDNP in the related cortical regions where large amount of amyloid deposited. In VD patients, only the striatum demonstrated lower clearance of 18^F-FDDNP. Conclusion 18^F-FDDNP PET imaging may be promising in providing reliable quantitative information on APs and NFTs in AD patients and in differentiating between AD and VD.