Event Abstract

IBMA: An SPM toolbox for NeuroImaging Image-Based Meta-Analysis

  • 1 University of Warwick, Warwick Manufacturing Group, United Kingdom
  • 2 University of Warwick, Department of Statistics, United Kingdom

Introduction
While most neuroimaging meta-analyses are based on peak coordinate data, the best practice method is an image-based meta-analysis that combines the effect estimates and the standard errors from each study [7]. Various efforts are underway to facilitate sharing of neuroimaging data to make such intensity-based meta-analysis possible (see, e.g. [4]).
When image data is available for each study, a number of approaches (see [6] for a review) have been proposed to perform such meta-analysis including combination of standardised statistics, just effect estimates or both effects estimates and their sampling variance. While the latter is the preferred approach in the statistical community [1], often only standardised estimates are shared, reducing the possible meta-analytic approaches.
In view of the increasing availability of image data for neuroimaging analyses, we introduce IBMA, a toolbox for SPM [8] providing a set of tools for image-based meta-analysis. The toolbox is freely available at: https://github.com/NeuroimagingMetaAnalysis/ibma.

Method
Using the IBMA toolbox, we studied six meta-analytic approaches based on:
- contrast estimates only: Random-effects General Linear Model (RFX GLM);
- contrast estimates and standard errors: Fixed-effects General Linear Model (FFX GLM);
- Z-statistic: Fisher’s [2], Stouffer [9], Mixed-effects (MFX) Stouffer [7];
- Z-statistic and sample size: Weighted-Z [5,10].
Out of these six approaches, two are random-effects methods (RFX GLM, Stouffer MFX) and therefore offers the possibility to deal with studies heterogeneity. The fixed-effects approaches are strictly only appropriate if the between-study variance is null.
Using 21 studies of pain in control subjects, we visually compared the results obtained at p< 0.05 FDR corrected using the six meta-analytic approaches. The reference results were computed with the best-practice analysis: a 3-level hierarchical model: level 1, subject FFX; level 2, study MFX; level 3: meta-analysis MFX, using FSL’s FLAME method [3].

Results and conclusion
Fig. 1 presents the detection obtained at p< 0.05 FDR corrected in a one-sample meta-analysis of pain using the IBMA toolbox. Further work will investigate the validity of each meta-analytic approach in the context of neuroimaging.

Figure 1

Acknowledgements

This work was supported by the Wellcome Trust. We also gratefully acknowledge the use of this data from the Tracey pain group, FMRIB, Oxford.

References

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"Statistical Parametric Mapping." SPM -. Accessed April 03, 2014. http://www.fil.ion.ucl.ac.uk/spm/
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Keywords: Meta-analysis, Neuroimaging, MRI, fMRI methods, Statistics as Topic, Toolbox, SPM

Conference: Neuroinformatics 2014, Leiden, Netherlands, 25 Aug - 27 Aug, 2014.

Presentation Type: Poster, to be considered for oral presentation

Topic: Neuroimaging

Citation: Maumet C and Nichols TE (2014). IBMA: An SPM toolbox for NeuroImaging Image-Based Meta-Analysis. Front. Neuroinform. Conference Abstract: Neuroinformatics 2014. doi: 10.3389/conf.fninf.2014.18.00025

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Received: 04 Apr 2014; Published Online: 04 Jun 2014.

* Correspondence: Dr. Camille Maumet, University of Warwick, Warwick Manufacturing Group, Coventry, United Kingdom, contact@camillemaumet.com