Meltzer C C, Zubieta J K, Brandt J, Tune L E, Mayberg H S, Frost J J
Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Neurology. 1996 Aug;47(2):454-61. doi: 10.1212/wnl.47.2.454.
Measurements of cerebral metabolism in patients with Alzheimer's disease (AD) using PET are artifactually depressed due to partial volume averaging of brain tissue activity with enlarged CSF spaces. To investigate the effects of correction for the expansion of CSF spaces on regional metabolic measures, as well as the correlations between neuropsychological test results and resting cerebral metabolism before and after partial volume correction, we applied an MRI-based method of partial volume correction to 18F-fluorodeoxyglucose (FDG)-PET data from eight patients diagnosed with probable AD and ten healthy elderly individuals. Before correction, the AD group had significantly lower cortex-to-cerebellum ratios in the posterior temporal, parietal, and frontal lobes in comparison to the control subjects. Partial volume correction of PET data resulted in 19 to 49% increases in regional activity in the AD group and 16 to 38% increases in the control group. The patients' persistence of significant hypometabolism in the frontal, posterior temporal, and parietal regions after partial volume correction suggests that a true reduction in regional cerebral glucose metabolism occurs in AD, even though its magnitude is a result of both metabolic reductions and the effects of atrophy. Partial volume correction of PET data in the AD group had a significant impact on the correlations between regional glucose metabolism and neuropsychological performance. These findings suggest that accounting for differential extent and distribution of cerebral atrophy in patients with AD and in healthy individuals may potentially improve our ability to interpret specific cognitive dysfunction in the context of the functional imaging data.
由于脑脊液间隙扩大导致脑组织活动的部分容积平均效应，使用正电子发射断层扫描（PET）对阿尔茨海默病（AD）患者进行脑代谢测量时会出现人为降低的情况。为了研究脑脊液间隙扩大校正对区域代谢测量的影响，以及部分容积校正前后神经心理学测试结果与静息脑代谢之间的相关性，我们对8例诊断为可能患有AD的患者和10名健康老年人的18F-氟脱氧葡萄糖（FDG）-PET数据应用了基于磁共振成像（MRI）的部分容积校正方法。校正前，与对照组相比，AD组颞叶后部、顶叶和额叶的皮质与小脑比值显著降低。PET数据的部分容积校正使AD组的区域活性增加了19%至49%，对照组增加了16%至38%。部分容积校正后，患者额叶、颞叶后部和顶叶区域仍存在显著的代谢减退，这表明AD患者区域脑葡萄糖代谢确实降低，尽管其程度是代谢降低和萎缩效应共同作用的结果。AD组PET数据的部分容积校正对区域葡萄糖代谢与神经心理学表现之间的相关性有显著影响。这些发现表明，考虑AD患者和健康个体脑萎缩的不同程度和分布，可能会提高我们在功能成像数据背景下解释特定认知功能障碍的能力。
