How should we compare QSM results? A correlation based analysis as an alternative to traditional error metrics

During the last QSM Workshop, the results of first “Quantitative Susceptibility Mapping (QSM) Reconstruction Challenge” were presented, which was performed to allow a systematic comparison of various QSM algorithms. One unresolved issue was the fact that the comparison metrics did not properly deal with the effect of smoothing. Here, we propose a comparison method based on pearson correlations, which are calculated over 1D lines throughout the QSM volumes, and show its robustness relative to other metrics under the influence of over-smoothing.