双相障碍Ⅱ型抑郁患者静息态磁共振低频振幅和功能连接分析

Amplitude of low-frequency fluctuation and functional connectivity analysis based resting-state functional magnetic resonance imaging study in bipolar Ⅱ depression patients

目的通过静息态功能磁共振成像技术探讨双相障碍Ⅱ型抑郁患者脑区自发性活动特征，及其可能的病理机制。方法纳入符合DSM-Ⅳ诊断标准的双相障碍Ⅱ型抑郁患者21例（患者组）及性别、年龄、受教育程度与之相匹配的21名健康对照者（对照组），采用蒙哥马利抑郁量表、HAMD17、HAMA评估症状严重程度；采用3.0 T GE磁共振进行静息态数据采集，低频振幅方法分析数据，并进行双样本t检验分析。将差异有统计学意义的脑区低频振幅均值与症状严重程度进行相关分析；并将差异有统计学意义的脑区作为感兴趣区与全脑进行功能连接分析，并进行组间比较。结果患者组左侧中央旁小叶（t=3.80）、右侧楔前叶（t=3.54）、右侧中央前回（t=3.66）低频振幅值高于对照组（均P〈0.05，GRF校正）。相关分析显示患者组左侧眶部额上回（r=0.75）、右侧眶部额上回（r=0.80）低频振幅值与HAMA总分呈正相关，双侧直回（r=0.73）及左侧岛叶附近脑区（r=0.74）低频振幅值与HAMD17总分呈正相关，右侧小脑脚2区（r=-0.65）低频振幅值与蒙哥马利抑郁量表总分呈负相关（均P〈0.05）。患者组中央旁小叶、楔前叶、中央前回与左侧额中回、左侧扣带回前部及其侧面环绕的脑回功能连接较对照组增强（t=4.47、4.07，均P〈0.05）；与右侧矩状裂及其周围皮质的功能连接较对照组减弱（t=4.54，P〈0.05）。结论双相障碍Ⅱ型抑郁患者左侧中央旁小叶、右侧楔前叶、右侧中央前回脑功能存在异常，并与临床症状严重程度有关，这可能是双相障碍Ⅱ型抑郁发病的神经功能基础。

Objective To examine the characteristics of spontaneous activity of brain regions in bipolar Ⅱ depression patients by using resting state fMRI technology, and explore the pathogenesis of bipolar Ⅱ depression. Methods In total 21 bipolar H depression patients （BD group） and 21 gender-, age- and education-matched healthy controls （HC group） were recruited. The patients were diagnosed according to the DSM-IV criteria, and the symptoms were evaluated by the Montgomery-Asberg Depression Rating Scale （MADRS）, HAMD17 and HAMA. The resting-state data was collected via a 3.0 T GE MRI, and was analyzed using an amplitude of low-frequency fluctuation （ALFF） approach, and two-samples t test was used to analyze the difference between BD group and HC group. Correlation analysis was used between the mean value of ALFF in brain regions which were significantly different from the other regions and the depression severity. The brain areas that were significantly different from the other brain regions were regarded as regions of interest, and were made functional connectivity with the whole brain. The functional connectivity was compared between the two groups to explore the impaired emotional network in bipolar Ⅱ depression. Results The ALFFs of left paracentral lobule（t=3.80）, right precuneus （t=3.54） and right precentral gyrus （t=3.66） in BD group were significantly higher than HC group （all P〈0.05, GRF correction）. In BD group, the ALFFs of the left orbital frontal gyrus （r=0.75） and right orbital frontal gyrus （r=0.80） were positively correlated with the HAMA score. The ALFFs of bilateral gyri rectus （r=0.73） and brain regions near the left insular lobe （r=0.74） were positively correlated with the HAMD17 score. The ALFF of region 2 of right cerebellar peduncles （r=-0.65） was negatively correlated with the MADRS score （all P〈0.05）. The functional connectivity between paraccntral lobule, precuneus, precentral gyms and left middle frontal gyms, left anterior cingulate gyrus together with its lateral gyms in BD group was significantly increased relative to HC group （t=4.47, 4.07; both P〈0.05）, while the functional connectivity between the right rectangular shape crack and the cortex around was decreased in BD group （t=4.54, P〈0.05）. Conclusion In bipolar Ⅱ depression patients, the brain function of left paracentral lobule, right precuneus and right precentral gyrus may he impaired and correlated with severity of depressive.