In multi-echo (ME) fMRI, data are acquired for multiple echo times, resulting in multiple time series for each voxel.
Multi-echo fMRI data is obtained by acquiring multiple TEs (commonly called echo times) for each MRI volume during data collection. While fMRI signal contains important neural information (termed the blood oxygen-level dependent, or BOLD signal, it also contains "noise" (termed non-BOLD signal) caused by things like participant motion and changes in breathing. Because the BOLD signal is known to decay at a set rate, collecting multiple echos allows us to assess whether components of the fMRI signal are BOLD- or non-BOLD. For a comprehensive review, see Kundu et al. (2017).
ME-EPI exhibits higher SNR and improves statistical power of analyses.
- A review on multi-echo fMRI and its applications
- A spreadsheet cataloguing papers using multi-echo fMRI, with information about acquisition parameters.
- An educational session from OHBM 2017 by Dr. Prantik Kundu about multi-echo denoising
- A series of lectures from the OHBM 2017 multi-echo session on multiple facets of multi-echo data analysis
- Multi-echo sequences: who has them and how to get them.
A small number of multi-echo datasets have been made public so far. This list is not necessarily up-to-date, so please check out OpenNeuro to potentially find more.