Artificial Correlations Induced by SENSE and GRAPPA Corrupt fcMRI Conclusions

Iain P. Bruce¹, Daniel B. Rowe¹, ²

In fcMRI, parallel MR image reconstruction models such as SENSE and GRAPPA can be used to reduce data acquisition time in an effort to both increase spatiotemporal resolution and more rapidly measure changes in the BOLD contrast. However, the correlations induced by these models can change the correlation coefficients between previously aliased voxels in sub-sampled data by contrast to data that was fully sampled. Depending on the sign of the induced correlation relative to the correlation inherent in the acquired data, this can result in either Type I or II errors in fcMRI when the hypothesis assumes no correlation exists.