Update - A number of articles linking to this post are wrongly stating that FreeSurfer is medical software used to diagnose diseases or measure the size of brain tumors. It's not. It is purely for research purposes asthe software license states, "The Software has been designed for research purposes only and has not been reviewed or approved by the Food and Drug Administration or by any other agency. CLINICAL APPLICATIONS ARE NEITHER RECOMMENDED NOR ADVISED."
Last month, neuroscientists were warned about potential biases in SPM8, a popular software tool for analysis of fMRI data.