Repeatability and Reproducibility of brain volume measurements with SPM and Freesurfer  and their impact on subtle between-group differences

The main aim of the study is to investigate whether the adoption of a processing method has a relevant influence on the results of a neuroimaging research. We evaluated the intra-method repeatability and the inter-method reproducibility of two widely-used automatic segmentation methods for brain MRI: FreeSurfer (FS) and Statistical Parametric Mapping (SPM) software packages. We segmented the gray matter, the white matter and the subcortical structures in test-retest MRI data of healthy volunteers from two publicly available datasets. High intra-method repeatability was found for both SPM and FS, but SPM was more consistent than FS in measuring ROIs volumes.