Evaluation Of Brain White Matter Lesion In Patients With Obstructive Sleep Apnea Hypopnea-syndrom With Magnetic Resonance Diffusion Tensor Imaging

Objective: Obstructive sleep apnea-hypopnea syndrome(OSAHS) is the most common sleep disorder that can result in fragmented sleep and chronically intermittent hypoxemia. And it is increasingly recognized as an independent risk factor for cardiac, neurologic, and perioperative morbidities with having memory deficits and cognitive dysfunction. Previous studies revealed that patients with OSA showed alterations in gray matter volume(GMV), metabolic product and function, and there are few studies for brain white matter and its microstructure lesion. In this study, to detection the integrality of brain white matter fibers in different brain regions, as well as its microstructure, and to discuss brain white matter lesion in patients with OSAHS using diffusion tensor imaging(DTI).Methods: Twenty-six male patients with OSAHS(mean age: 43.19 ± 8.97 years, range from 30 to 59 years) and Twenty-two male healthy controls(mean age: 44.09 ± 8.62 years, range from 31 to 58 years) matched for age and gender, were included in this study. Each participant had no mental or neurological disorders, traumatic brain injuries, major cardiovascular disease, diabetes mellitus, without smoking, drinking and any medications. Two groups were performed DTI scan if there is no structural abnormalities after common brain mri scans. The DTI data were processed with the DTI Studio and the software of REST and SPM8 on the Matlab. We got the fractional anisotmpy(FA), axial diffusivity(AD) and radial diffusivity(RD) maps, then, to analyse the maps using voxel-based analysis(VBA) and make the statistical analysis using a two-sample t-test. Next, we can got the changes of each parameter value in the OSAHS, compared to control subjects. And at last, it is concluded that the brain areas and cluster sizes with statistically significantly in the two groups.Results:1 In a comparison between OSAHS and control subjects, the vaules of FA were significantly reduced in bilateral superior frontal gyrus, middle frontal gyrus, anterior cingulate, posterior cingulate, superior parietal lobule, inferior parietal lobule, insula, middle temporal gyrus, limbic lobe, middle occipital gyrus, fusiform gyrus, hippocampus, caudate nucleus, putamen, anterior ventral nucleus, amygdala; left superior parietal lobule, precuneus, superior temporal gyrus, the left parts of the brainstem, lingual gyrus; right putamen, claustrum, thalamus, ventral lateral nucleus, postcentral gyrus and the right part of corpus callosum.2 In a comparison between OSAHS and control subjects, the vaules of AD were significantly reduced in bilateral precentual gyrus, fusiform gyrus, limbic lobe, parahippocampal gyrus, lingual gyrus, precuneus, inferior frontal gyrus, middle frontal gyrus, posterior cingulate gyrus, middle occipital gyrus, cingulate; right anterior cingulate cortex and adjacent cingulate, postcentral gyrus, anterior cerebellar lobe, the right part of brainstem, the right parts of the corpus callosum; left inferior frontal gyrus, insula, superior parietal lobule, inferior parietal gyrus.3 In a comparison between OSAHS and control subjects, the vaules of RD were significantly reduced in bilateral middle temporal gyrus, insula, precuneus, posterior cingulate, middle frontal gyrus, inferior frontal gyrus, inferior parietal lobule, postcentral gyrus, cingulate, anterior cerebellar lobe, brainstem, left cerebellum posterior lobe, limbic lobe, anterior cingulate gyrus, middle occipital gyrus, claustrum, superior parietal lobule; right superior temporal gyrus, inferior temporal gyrus, fusiform gyrus, inferior occipital gyrus, hippocampus, putamen and angular gyrus.Conclusions:1 Multiple regions of lower FA, AD and RD appeared within white matter in the OSAHS group, which indicated that white matter is extensively affected in OSAHS patients.2 The white matter microstructure can be qualitative analysis using the VBA method based on DTI, which can evaluate brain white matter lesion in OSAHS patiens.3 Myelin changes were more widespread than axonal changes in OSAHS, indicating predominant myelin pathology over axonal injury, and myelin is more vulnerable to hypoxia than axons.