SENSE & Susceptibility: Respiration-Related Susceptibility Effects and their Interactions with Parallel Imaging

Abstract

Most functional MRI studies rely on fast Echo Planar Imaging, which is sensitive to magnetic susceptibility effects. These effects can lead to image-to-image signal instability, reducing the reliability of functional activation maps. Respiration is responsible for a significant component of image-to-image variance, but no widely effective method for correcting respiration-based susceptibility effects is available. We demonstrate a relationship between respiration-related susceptibility effects in the presence of parallel imaging acquisitions and apply our findings to analyze the behavior of IMPACT (IMage-based Physiological Artifact Correction Technique). Based on our findings regarding IMPACT, we propose COMPACT (Center of Mass-based Physiological Artifact Correction Technique), a new method which provides a reliable estimate of respiratory effects based on the motion of an image set’s center of mass (centroid) through time.