LENITEM Laboratory of Epidemiology, Neuroimaging, and Telemedicine, IRCCS San Giovanni di Dio-FBF, 25125 Brescia, Italy.
Neurobiol Aging. 2010 Mar;31(3):387-97. doi: 10.1016/j.neurobiolaging.2008.05.001. Epub 2008 Jun 13.
Aim of this study was to investigate the functional compensation mechanism in incipient Alzheimer's disease (AD). Seventeen elderly healthy subjects and nine amnestic MCI patients with incipient AD underwent brain MR scan and 99mTc ECD SPECT. We processed all images with SPM2, we created t maps, showing the wholebrain GM atrophy and functional changes, and we properly masked them with each other in order to assess relatively preserved perfusion or depression. Incipient AD showed GM atrophy in the medial temporal and temporoparietal lobes, in the insula and in the retrosplenial cortex, and GM hypoperfusion in the medial temporal and temporoparietal lobes. Relatively preserved perfusion, we could hypothesize to be compensatory in the setting of neuronal loss, was found in the posterior cingulate, in the head of the hippocampus, in the amigdala, and in the insula bilaterally, while functional depression occurred in bilateral parahippocampal gyri. In AD, a perfusional compensatory mechanism takes place in the neocortex, while perfusional depression occurs in the medial temporal lobe. These results help understand the reactive phenomena induced by the brain to try and counteract the pathological changes of AD.
本研究旨在探讨早期阿尔茨海默病（AD）中的功能代偿机制。17 名老年健康受试者和 9 名有早期 AD 记忆障碍的 MCI 患者接受了脑部磁共振扫描和 99mTc ECD SPECT 检查。我们使用 SPM2 处理所有图像，创建 t 映射，显示全脑 GM 萎缩和功能变化，并相互适当掩蔽，以评估相对保留的灌注或抑郁。早期 AD 患者的内侧颞叶和颞顶叶、岛叶和后扣带回皮质出现 GM 萎缩，内侧颞叶和颞顶叶 GM 灌注减少。我们假设在神经元丢失的情况下，后扣带回、海马头部、杏仁核和双侧岛叶出现相对保留的灌注是一种代偿机制，而双侧海马旁回则出现功能抑制。在 AD 中，新皮质中存在灌注代偿机制，而内侧颞叶则出现灌注抑制。这些结果有助于理解大脑为对抗 AD 的病理变化而产生的反应性现象。
