J Psychiatry Neurosci 2013; 38(1):49-56
Yi Liao, MD;* Xiaoqi Huang, MD, PhD;* Qizhu Wu, PhD; Chuang Yang, MD; Weihong Kuang, MD; Mingying Du, MD; Su Lui, MD, PhD; Qiang Yue, MD; Raymond C.K. Chan, PhD; Graham J. Kemp, MA, DM; Qiyong Gong, MD, PhD
Liao, Huang, Wu, Du, Lui, Yue, Gong — Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China; Yang — Department of Psychiatry, Wenzhou Medical School, Wenzhou, China; Kuang — Department of Psychiatry, State Key Lab of Biotherapy, West China Hospital of Sichuan University, Chengdu, China; Chan — Neuropsychology and Applied Cognitive Neuroscience Laboratory & Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Kemp — Magnetic Resonance and Image Analysis Research Centre (MARIARC) and Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom.
*Y. Liao and X. Huang contributed to the work equally.
Background: Many studies using diffusion tensor imaging (DTI) have demonstrated impaired white matter integrity in patients with major depressive disorder (MDD), with significant results found in diverse brain regions. We sought to identify whether there are consistent changes of regional white matter integrity in patients with MDD, as shown by decreased fractional anisotropy in DTI.
Method: A systematic search strategy was used to identify relevant whole brain voxel-based DTI studies of patients with MDD in relation to comparison groups. Relevant databases were searched for studies published between January 1994 and February 2011 using combinations of the terms “DTI” or “diffusion tensor;” “whole brain” or “voxel-based;” and “depress*.” Using the studies that met our inclusion criteria, we performed a meta-analysis of the coordinates of decreased fractional anisotropy using the activation likelihood estimation (ALE) method, which detects 3-dimensional conjunctions of coordinates from multiple studies, weighted by sample size. We then used DTIquery software for fibre tracking to locate the fascicles involved in each region.
Results: We included 11 studies with a combined sample of 231 patients with MDD and 261 comparison participants, providing 50 coordinates of decreased fractional anisotropy. Our meta-analysis identified 4 consistent locations of decreased fractional anisotropy in patients with MDD: white matter in the right frontal lobe, right fusiform gyrus, left frontal lobe and right occipital lobe. Fibre tracking showed that the main fascicles involved were the right inferior longitudinal fasciculus, right inferior fronto-occipital fasciculus, right posterior thalamic radiation and interhemispheric fibres running through the genu and body of the corpus callosum.
Limitations: The number of studies included was relatively small, and the DTI data acquisition and analysis techniques were heterogeneous. The ALE method cannot handle studies with no significant group differences.
Conclusion: Voxel-based analysis of DTI studies of patients with MDD consistently identified decreased fractional anisotropy in the white matter fascicles connecting the prefrontal cortex within cortical (frontal, temporal and occipital lobes) and subcortical areas (amygdala and hippocampus). This is strong evidence for the involvement of these neural circuits in the pathology of MDD.
Submitted Nov. 21, 2011; Revised Mar. 9, Apr. 16, 2012; Accepted Apr. 19, 2012.
Acknowledgements: This study was supported by National Natural Science Foundation (Grant Nos. 81171488 and 81030027) and the National Key Technologies R&D Program of China (Program No: 2012BAI01B03). We would also like to thank Dr. Jun Li for her suggestions regarding statistical methodology.
Competing interests: None declared.
Contributors: Y. Liao, X. Huang and Q. Gong designed the study and wrote the article. Y. Liao, X. Huang, Q. Wu, C. Yang and M. Du acquired the data, which Y. Liao, X. Huang, Q. Wu, C. Yang, W. Kuang, S. Lui, Q. Yue, R.C.K. Chan and G.J. Kemp analyzed. All authors reviewed the article and approved its publication.
Correspondence to: Q. Gong, Professor of Radiology, Neurology and Psychiatry, Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, China; email@example.com