Multiband acquisition sequences for fMRI: Proceed with caution

Abstract

Multiband or simultaneous multi-slice acquisition sequences for fMRI have become popular over the last decade, partly because of the influence of the approach taken in large-scale studies such as the Human Connectome Project. However, applying this type of highly-accelerated, high-resolution sequence to smaller-scale projects may come with significant drawbacks in terms of signal to noise ratio, reliability, and experimental power. In particular, the use of smaller voxels, short repetition times, and high levels of multiband acceleration may have strong negative effects on signal to noise, image artefacts, and signal dropout in medial and ventral brain regions. Multiband sequences can be valuable tools, particularly for specialist applications, but should be applied in smaller-scale studies judiciously, with a focus on a particular project’s endpoints, and after appropriate testing and pilot work.