Brain grey matter volume alterations in treatment resistant depression -- systematic review and meta-analysis
Xin Xu1, Jia Liu2, and Qiyong Gong2

1Department of Psychiatry, Huaxi MR Research Center(HMRRC),West China Hospital of Sichuan Universityl, Chengdu, China, People's Republic of, 2Department of Radiology, Huaxi MR Research Center(HMRRC),West China Hospital of Sichuan Universityl, Chengdu, China, People's Republic of

Synopsis

To our knowledge, this is the first study to pool VBM studies for a meta-analysis of grey matter differences among the treatment-sensitive depression (TSD), treatment-resistant depression (TRD) and health control (HC) by using anisotropic effect-size signed differential mapping (AES-SDM). Although both TRD and TSD groups showed abnormal grey matter in frontal and temporal cortex, the exact brain regions were mostly different in both groups except the left inferior frontal gyrus (IFG). Furthermore, grey matter volume reductions in the bilateral cingulate cortex were only observed in the TRD group.

Purpose

To investigate grey matter differences among the treatment-resistant depression (TRD) treatment-sensitive depression (TSD) and health control (HC).

Methods

A systematic search was conducted up to 2015 to identify studies focus on TSD patients or TRD patients. Grey matter differences between the patients and HC were analyzed by using anisotropic effect-size signed differential mapping (AES-SDM). AES-SDM is a voxel-based meta-analytic approach (Radua J, et al, 2014) that uses the reported anisotropic kernels to re-create maps of the effect size of group differences in grey matter. Moreover, AES-SDM also allows meta-analytic group comparisons (Radua J, et al, 2013) , which provide an indication of where computed effect sizes differ significantly between groups. So the similarities and differences between the TSD and TRD groups were also identified by effect size comparison and conjunction analysis.

Results

A total of 10 datasets met the inclusion criteria (see Figure 1 for details). Results were combined to identify grey matter abnormalities in TRD group compared with HC across 6 datasets (140 patients vs. 152 control subjects) and TSD group compared with HC across 8 datasets (183 patients vs. 292 control subjects). A group comparison of TRD patients with HC (see Figure 2 for details) revealed grey matter volume reductions in the bilateral median cingulate cortex (MCC), anterior cingulate cortex (ACC), the left inferior frontal gyrus (IFG), superior temporal gyrus (STG), middle temporal gyrus(MTG) and the right superior frontal gyrus (SFG). And grey matter increase was identified in the left lingual gyrus (LG) in TRD group compared to HC. In TSD group, grey matter increase was observed in the bilateral STG, insula, the left MTG, the right IFG, supramarginal gyrus(SMG), heschl gyrus (HG), rolandic operculum and postcentral gyrus. Moreover, when compared with HC, the TSD group shows reduced grey matter in left IFG, insula and gyrus rectus. In addition, comparison of effect sizes revealed that TRD patients showed greater reductions in grey matters in left IFG in comparison with TSD participants. And conjunction analysis confirmed it.

Discussion

To our knowledge, this is the first study to pool VBM studies for a meta-analysis of grey matter differences among TRD, TSD and HC. Although both TRD and TSD groups showed grey matter alteration in frontal and temporal cortex in comparison with HC group, only grey matter volume reduction in the left IFG was revealed in both TRD and TSD groups. The decreased grey matter in the right SFG was only detected in the TRD group and increased grey matter in the right IFG was only observed in the TSD group. Meanwhile, grey matter volume of left STG and MTG were decreased in the TRD group while they were increased in the TSD group. Furthermore, grey matter volume reductions in the bilateral MCC, ACC and grey matter increased in the lingual gyrus were only observed in the TRD group. In addition, abnormal grey matter in insula was only demonstrated in the TSD group.

Conclusions

Both TRD and TSD groups showed grey matter alterations in the cortical-limbic circuit. Although both TRD and TSD groups showed abnormal grey matter in frontal and temporal cortex, the exact brain regions were mostly different in both groups except the left IFG. Furthermore, grey matter volume reductions in the bilateral cingulate cortex were only observed in the TRD group and abnormal grey matter in insula was only demonstrated in the TSD group.

Acknowledgements

No acknowledgement found.

References

Radua J, et al (2013): A general approach for combining voxel-based meta-analyses conducted in different neuroimaging modalities. Curr Med Chem 20:462–466.

Radua J, et al (2014), Anisotropic kernels for coordinate-based meta-analyses of neuroimaging studies. Front Psychiatry. 2014 Feb 10;5:13.

Figures

Figure 1 Meta-analysis of voxel-based morphometry studies in TRD and TSD groups in comparison with HC group

The areas of decreased (blue) and increased (red) grey matter volumes in treatment-resistant depression (TRD, A) and treatment-sensitive depression (TSD, B) groups in comparison with health control (HC) group in the meta-analysis. Grey matter volume changes are displayed on a 3-dimensionally rendered brain, with part of the left or right hemisphere removed. L = Left; R = right.



Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)
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