A simple way to improve anatomical mapping of functional brain imaging.

Background And Purpose: Advances in functional neuroimaging studies have led to the need for improved anatomical precision to face with more and more specific challenges. Nevertheless, functional magnetic resonance imaging (MRI) (fMRI) suffers from geometrical distortions, which limit the matching between functional and anatomical data necessary to interpret fMRI results. The "FieldMap" method is the most widely used technique to correct for geometrical distortions but in some cases cannot be applied or provides unsatisfactory results. The objective of this study is thus to provide a very simple alternative method for distortion correction and to demonstrate its efficiency.

Methods: This correction relies on the nonlinear registration of echo-planar imaging (EPI) acquisitions onto their corresponding undistorted non-EPI T2 Star volume, and was tested on two independent groups of subjects undertaking the same paradigm but scanned with distinct EPI sequences.

Results: This procedure was found to considerably decrease the mismatch between functional and anatomical data in both groups, as revealed through several quantitative and qualitative measures on both EPI volumes and activation maps.

Conclusion: This study describes a simple, rapid, and easily implementable method to significantly improve neuroanatomical accuracy of fMRI results localization, which may be relevant for future neuroimaging studies.