Practical implications of motion correction with motion insensitive radial k-space acquisitions in MRI

Objectives:To highlight specific instances when radial k-space acquisitions in magnetic resonance imaging result in image artifacts and how to ameliorate such artifacts.Methods:We acquired axial T2 weighted MR images on (1) the American College of Radiology (ACR) phantom and (2) a sedated sheep with rectilinear and multi-blade radial k-space filling acquisitions. Images were acquired on four (2 × 1.5T and 2 × 3T) different MRI scanners. For the radial k-space acquisitions, we acquired images with and without motion correction. All images were visually inspected for the presence of artifact.Results:Images collected via the conventional rectilinear method were of diagnostic quality and free of artifact. Both ACR and sheep images acquired with radial k-space acquisitions and motion correction suffered significant artifact at different slice locations, scan sessions, and across all the four scanners. Severity of the artifact was associated with echo train length. However, the artifact was eliminated when moti...