Thomann Philipp A, Dos Santos Vasco, Seidl Ulrich, Toro Pablo, Essig Marco, Schröder Johannes
Section of Geriatric Psychiatry, University of Heidelberg, Heidelberg, Germany.
J Alzheimers Dis. 2009;17(1):213-21. doi: 10.3233/JAD-2009-1036.
There is increasing histopathological evidence that the olfactory bulb and tract (OBT) is a primary focus of neurodegenerative changes in Alzheimer's disease (AD). Correspondingly, high-resolution magnetic resonance imaging revealed significant atrophy of the OBT in manifest AD. Whether these alterations are already present in mild cognitive impairment, the assumed preclinical stage of AD, has not been investigated yet. OBT volumes were assessed by manual tracing in 29 patients with mild cognitive impairment, 27 patients with probable AD, and 30 healthy controls. In a second step, voxel based morphometry was used to investigate the potential association between OBT atrophy and morphological changes in other brain regions. Patients had significantly lower OBT volumes when compared to controls, with atrophy being most prominent in the AD group. In addition, OBT atrophy was associated with a decreased medial temporal lobe (MTL) gray matter density bilaterally. Our findings indicate that neurodegeneration in OBT and MTL regions is linked and suggest that OBT volume might be a surrogate marker in AD.
越来越多的组织病理学证据表明，嗅球和嗅束（OBT）是阿尔茨海默病（AD）神经退行性变的主要焦点。相应地，高分辨率磁共振成像显示，显性AD患者的OBT出现明显萎缩。这些改变是否已经存在于轻度认知障碍（AD假定的临床前期）中，尚未得到研究。通过手工描绘评估了29例轻度认知障碍患者、27例可能患有AD的患者和30名健康对照者的OBT体积。第二步，采用基于体素的形态测量法研究OBT萎缩与其他脑区形态学变化之间的潜在关联。与对照组相比，患者的OBT体积显著降低，萎缩在AD组最为明显。此外，双侧OBT萎缩与内侧颞叶（MTL）灰质密度降低有关。我们的研究结果表明，OBT和MTL区域的神经退行性变是相关的，并提示OBT体积可能是AD的替代标志物。
