Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, California, USA.
J Neurosci Res. 2012 Oct;90(10):2043-52. doi: 10.1002/jnr.23083. Epub 2012 Jun 20.
Obstructive sleep apnea (OSA) is a common and progressive disorder accompanied by severe cardiovascular and neuropsychological sequelae, presumably induced by brain injury resulting from the intermittent hypoxia and cardiovascular processes accompanying the syndrome. However, whether the predominant brain tissue pathology is acute or chronic in newly-diagnosed, untreated OSA subjects is unclear; this assessment is essential for revealing pathological processes. Diffusion tensor imaging (DTI)-based mean diffusivity (MD) procedures can detect and differentiate acute from chronic pathology and may be useful to reveal processes in the condition. We collected four DTI series from 23 newly-diagnosed, treatment-naïve OSA and 23 control subjects, using a 3.0-Tesla magnetic resonance imaging scanner. Mean diffusivity maps were calculated from each series, realigned, averaged, normalized to a common space, and smoothed. Global brain MD values for each subject were calculated using normalized MD maps and a global brain mask. Mean global brain MD values and smoothed MD maps were compared between groups by using analysis of covariance (covariate: age). Mean global brain MD values were significantly reduced in OSA compared with controls (P = 0.01). Multiple brain sites in OSA, including medullary, cerebellar, basal ganglia, prefrontal and frontal, limbic, insular, cingulum bundle, external capsule, corpus callosum, temporal, occipital, and corona radiata regions showed reduced regional MD values compared with controls. The results suggest that global brain MD values are significantly reduced in OSA, with certain regional sites especially affected, presumably a consequence of axonal, glial, and other cell changes in those areas. The findings likely represent acute pathological processes in newly-diagnosed OSA subjects.
阻塞性睡眠呼吸暂停（OSA）是一种常见且进展性的疾病，伴有严重的心血管和神经心理学后遗症，推测是由间歇性低氧和伴随该综合征的心血管过程引起的脑损伤所致。然而，在新诊断、未经治疗的 OSA 患者中，主要的脑组织病理学是急性还是慢性尚不清楚；这种评估对于揭示病理过程至关重要。基于弥散张量成像（DTI）的平均弥散度（MD）程序可以检测和区分急性和慢性病变，并且可能有助于揭示该病症的过程。我们从 23 名新诊断、未经治疗的 OSA 和 23 名对照受试者中收集了四个 DTI 系列，使用 3.0 特斯拉磁共振成像扫描仪。从每个系列中计算平均弥散度图，进行重新配准、平均化、归一化为共同空间并进行平滑处理。使用归一化 MD 图和全脑掩模计算每个受试者的全脑 MD 值。通过协方差分析（协变量：年龄）比较组间的平均全脑 MD 值和平滑 MD 图。与对照组相比，OSA 的平均全脑 MD 值显著降低（P = 0.01）。与对照组相比，OSA 中包括延髓、小脑、基底节、前额和额叶、边缘系统、岛叶、胼胝体束、外囊、胼胝体、颞叶、枕叶和放射冠区域在内的多个脑区的局部 MD 值降低。结果表明，OSA 的全脑 MD 值显著降低，某些区域的特定部位尤其受到影响，推测是这些区域的轴突、胶质和其他细胞变化的结果。这些发现可能代表新诊断的 OSA 患者中急性的病理过程。
