Magnetic resonance elastography: A comparison between pulse sequences across field strengths

摘要

Several Magnetic Resonance Elastography (MRE) techniques have been developed to non-invasively measure tissue stiffness which can be altered by disease processes such as liver fibrosis. Different MRE sequences are needed to fill various roles clinically such as spin-echo based sequences for patients with iron overload, or rapid sequences for patients who cannot execute long breath holds. The purpose of this study was to compare the mean stiffness, variance, and presence of artifacts using three MRE sequences at 1.5T and 3T in phantoms and healthy volunteers. In the phantom study variance was found to decrease with increasing slice thickness as well as at higher field strength. The SE-EPI sequence tended to overestimate low stiffness and underestimate high stiffness while the rapid sequence significantly overestimated stiffness of both the soft and stiff phantom. In the volunteers no significant difference was found between the sequences in terms of measured stiffness. The variability between acquisitions in a single setup as well as between setups was minimal, showing that MRE is a very robust technique.