title: Voxel-wise meta-analyses of brain blood flow and local synchrony abnormalities in medication-free patients with major depressive disorder.
abstract: BACKGROUND
  Published meta-analyses of resting-state regional cerebral blood flow (rCBF) studies of major depressive disorder (MDD) have included patients receiving antidepressants, which might affect brain activity and thus bias the results. To our knowledge, no meta-analysis has investigated regional homogeneity changes in medication-free patients with MDD. Moreover, an association between regional homogeneity and rCBF has been demonstrated in some brain regions in healthy controls. We sought to explore to what extent resting-state rCBF and regional homogeneity changes co-occur in the depressed brain without the potential confound of medication.
  
  
  METHODS
  Using the effect-size signed differential mapping method, we conducted 2 meta-analyses of rCBF and regional homogeneity studies of medication-free patients with MDD.
  
  
  RESULTS
  Our systematic search identified 14 rCBF studies and 9 regional homogeneity studies. We identified conjoint decreases in resting-state rCBF and regional homogeneity in the insula and superior temporal gyrus in medication-free patients with MDD compared with controls. Other changes included altered resting-state rCBF in the precuneus and in the frontal-limbic-thalamic-striatal neural circuit as well as altered regional homogeneity in the uncus and parahippocampal gyrus. Meta-regression revealed that the percentage of female patients with MDD was negatively associated with resting-state rCBF in the right anterior cingulate cortex and that the age of patients with MDD was negatively associated with rCBF in the left insula and with regional homogeneity in the left uncus.
  
  
  CONCLUSIONS
  The analysis techniques, patient characteristics and clinical variables of the included studies were heterogeneous.
  
  
  CONCLUSIONS
  The conjoint alterations of rCBF and regional homogeneity in the insula and superior temporal gyrus may be core neuropathological changes in medication-free patients with MDD and serve as a specific region of interest for further studies on MDD.
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Zi-Qi
authors: ZQ
authors: Chen
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Ming-Ying
authors: MY
authors: Du
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: You-Jin
authors: YJ
authors: Zhao
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Xiao-Qi
authors: XQ
authors: Huang
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Jing
authors: J
authors: Li
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Su
authors: S
authors: Lui
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Jun-Mei
authors: JM
authors: Hu
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Huai-Qiang
authors: HQ
authors: Sun
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Jia
authors: J
authors: Liu
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Graham J
authors: GJ
authors: Kemp
authors: Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China (Chen, Du, Zhao, Huang, Lui, Sun, Liu, Gong); Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China (Li, Hu); Magnetic Resonance and Image Analysis Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom (Kemp).
authors: Qi-Yong
authors: QY
authors: Gong
mesh_terms: D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003344:Cortical Synchronization / Q000502:physiology*; D003865:Major Depressive Disorder / Q000503:physiopathology*; D006801:Humans; D012146:Rest