Removal of Residual Motion Artifacts in FMRI Using Constrained Independent Component Analysis

Kiran Kumar Pandey¹, Douglas C. Noll¹

Image-registration in fMRI only corrects for bulk movements, leaving secondary artifacts - spin history, motion induced field inhomogeneity changes, interpolation errors - untouched. Secondary artifacts increase variance and reduce sensitivity of fMRI. Methods using motion parameters as Nuisance Explanatory Variables or ICA are used to isolate/remove residual motion artifacts. Use of ICA requires isolation and then identification of motion components before removal. We used constrained ICA to isolate/identify these components in one step using motion parameters as references. Use of cICA efficiently and effectively removed residual motion artifacts without manual identification step and, increased the sensitivity of BOLD fMRI studies.