The effects of multi-echo fMRI combination and rapid T*-mapping on offline and real-time BOLD sensitivity

• DOI: 10.1016/j.neuroimage.2021.118244
• Publication Date: 2021-06-08T16:32:49Z
• Authors: Stephan Heunis; Marcel Breeuwer; César Caballero-G...; Lydia Hellrung; Willem Huijbers; Jacobus FA Jansen; Rolf Lamerichs; Svitlana Zinger; Albert P Aldenkamp
• Keywords: methods development; Functional magnetic resonance imaging; Emotions; ESSB PSY; adaptive paradigms; ACTIVATION; 0302 clinical medicine; 10007 Department of Economics; Task; BRAIN; Resting state; time; info:eu-repo/classification/ddc/610; Brain Mapping; Multi-echo; Brain; neurofeedback; amygdala; Neurofeedback; Amygdala; Magnetic Resonance Imaging; motor; 330 Economics; echo; finger tapping; Motor; SEPARATION; Real; RC321-571; TOOLBOX; task; Neurosciences. Biological psychiatry. Neuropsychiatry; Emotion processing; 03 medical and health sciences; ENHANCEMENT; CONTRAST SENSITIVITY; Humans; Finger tapping; OPTIMIZATION; Methods development; resting state; emotion processing; Reproducibility of Results; QUANTIFICATION; Adaptive paradigms; functional magnetic resonance imaging; SIGNAL; EPI; multi; Real-time

AbstractA variety of strategies are used to combine multi-echo functional magnetic resonance imaging (fMRI) data, yet recent literature lacks a systematic comparison of the available options. Here we compare six different approaches derived from multi-echo data and evaluate their influences on BOLD sensitivity for offline and in particular real-time use cases: a single-echo time series (based on Echo 2), the real-timeT2*-mapped time series (T2*FIT) and four combined time series (T2*-weighted, tSNR-weighted, TE-weighted, and a new combination scheme termedT2*FIT-weighted). We compare the influences of these six multi-echo derived time series on BOLD sensitivity using a healthy participant dataset (N=28) with four task-based fMRI runs and two resting state runs. We show that theT2*FIT-weighted combination yields the largest increase in temporal signal-to-noise ratio across task and resting state runs. We demonstrate additionally for all tasks that theT2*FITtime series consistently yields the largest offline effect size measures and real-time region-of-interest based functional contrasts. These improvements show the possible utility of multi-echo fMRI for studies employing real-time paradigms, while caution is still advised due to decreased tSNR of theT2*FITtime series. We recommend the use and continued exploration ofT2*FITfor offline task-based and real-time fMRI analysis. Supporting information includes: a data repository (https://dataverse.nl/dataverse/rt-me-fmri), an interactive web-based application to explore the data (https://rt-me-fmri.herokuapp.com/), and further materials and code for reproducibility (https://github.com/jsheunis/rt-me-fMRI).