REAL-TIME ADAPTIVE MOTION CORRECTION IN FUNCTIONAL MRI

Functional magnetic resonance imaging (fMRI) of the brain is often deg raded by bulk head motion, Algorithms that address this by retrospecti ve re-registration of images in an fMRI time series are all fundamenta lly limited by any motion that occurs through-plane. Here, a technique is described that can account for such motion by prospective correcti on in real time. A navigator echo is used before every image acquisiti on to detect superior/inferior displacements of the head, The displace ment information is then used to adjust the plane of excitation of the ensuing single-shot echo-planar fMRI axial image. These correction up dates can be completed in 100 ms with motion sensitivity at least as s mall as 0.5 mm, The efficacy of this method is documented in phantom a nd human studies.