嗅觉功能障碍首发抑郁症患者的弥散张量成像研究

Diffusion tensor imaging of patients with first-episode depression complicated by olfactory dysfunction

目的探讨首发抑郁症患者是否合并嗅觉功能障碍,利用弥散张量成像(diffusion tensor imaging,DTI)技术研究嗅觉功能障碍首发抑郁症患者脑白质结构改变及其与抑郁严重程度的相关性。方法选取本院2016年4月至2017年6月首发抑郁症患者37例为研究组,同期性别、年龄及受教育程度相匹配的志愿者38例为对照组,均进行24项汉密尔顿抑郁量表(24-item Hamilton depression rating scale,HDRS24)评分;比较两组嗅觉测试结果的差异。根据嗅觉测试结果,将研究组中17例嗅觉减退的首发抑郁症患者列为研究A组,20例无嗅觉减退的首发抑郁症患者为研究B组,分别对研究A组及研究B组进行DTI扫描,运用基于纤维束示踪的空间统计分析方法(tract-based spatial statistics,TBSS)得到各向异性分数(fractional anisotropy,FA),比较研究A组与研究B组的颅脑FA值差异。结果与对照组比较,首发抑郁症患者嗅觉测试值降低(P<0.01);与研究B组比较,研究A组左侧海马、胼胝体膝部FA值降低(P<0.01,FDR校正),未发现FA值显著增加区域。研究A组嗅觉测试值与HDRS24量表评分呈负相关(r=-0.519,P=0.033),左侧海马、胼胝体膝部下降的FA值与HDRS24量表评分无显著相关性(r左侧海马=0.163,r胼胝体膝部=-0.104;P>0.05)。结论首发抑郁症患者可合并嗅觉功能障碍;嗅觉功能障碍首发抑郁症患者存在相关嗅觉通路的损害,但FA值下降与抑郁严重程度无显著相关性。

Objective To explore whether patients with first-episode depression have the co-morbidity of olfactory dysfunction and investigate the correlation between white matter changes and the severity of depression in patients with concurrent olfactory disorder using diffusion tensor imaging（ DTI）. Methods Olfactory test was used to evaluate the olfactory function in 37 patients with first-episode depression who were admitted in our hospital from April 2016 to June 2017 and 38 gender-,age-and education-matched healthy control subjects. All the participants were examined using 24-item Hamilton depression rating scale（ HDRS24）. According to olfactory test results,the depressive patients were divided into group A with olfactory dysfunction（ n = 17） and group B without olfactory dysfunction（ n = 20）. All the patients underwent DTI examination,and the fractional anisotropy（ FA） acquired using tract-based spatial statistics（ TBSS） were compared between groups A and B. Results Compared with the healthy controls,the patients with firstepisode depression had a significant deterioration of the olfactory function（ P 0. 01）. Compared with those in group B,the depressive patients in group A showed significantly lower mean FA values in the left hippocampus and in the genu of the corpus callosum（ P 0. 01,FDR corrected）,but no brain regions with increased FA values were detected. In group A,an inverse correlation was noted between the olfactory test results and HDRS24 scores（ r =-0. 519,P = 0. 033）,but no correlation was found between the decreased FA values in the white matter and HDRS24 scores（ r = 0. 163 for the left hippocampus and r =-0. 104 for the genu of the corpus callosum,P 0. 05）. Conclusion Patients with first-episode depression can have the co-morbidity of olfactory dysfunction possibly as a result of olfactory pathway impairments. The lower FA values in the white matters are not correlated with the severity of depression in such patients.