Hi,
I'm going run a simultaneous fMRI , eye tracking experiment. I expect having head some movement artefacts because of the eye tracking calibration. I think in multiband imaging we have two images at the same time and each of them have their own head movement artefact. I was wondering whether muti-bamd imaging increases the head movement artefact in my experiment?
Many thanks
With multiband imaging two or more slices are acquired simultaneously. Typically the number is in 4 to 8 slices, but I have seen up to 16 reported. Since the slices are acquired simultaneously, the motion affects should be the same among that set of slices.
With multiband though you need calibration data to do the reconstruction and the calibration data is normally acquired during the prescan, Motion results in a misalignment with respect to the calibration data which will degrade the reconstruction leading to increased ghosting (signal leakage) and/or noise. The same issue exists with in-plane acceleration methods such as GRAPPA and SENSE.
The kind of motion affect you are describing, slice-to-slice motion, is more of a problem in non-multiband EPI. The longer it takes to acquire the volume, the more sensitive you will be to this issue. With multi-band, if you keep the matrix size constant, you reduce the minimum Tr needed to acquire the volume and so reduce the impact of slice-to-slice motion.
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