title: Influence of the FID and off-resonance effects in dense MRI.
abstract: Accurate functional measurement in cardiovascular diseases is important as inaccuracy may compromise diagnostic decisions. Cardiac function can be assessed using displacement encoding with stimulated echoes, resulting in three signal components. The free induction decay (FID), arising from spins undergoing T(1) -relaxation, is not displacement encoded and impairs the displacement acquired. Techniques for suppressing the FID exist; however, a residual will remain. The effect of the residual is difficult to distinguish and investigate in vitro and in vivo. In this work, the influence of the FID as well as of off-resonance effects is evaluated by altering the phase of the FID in relation to the stimulated echo. The results show that the FID and off-resonance effects can impair the accuracy of the displacement measurement acquired. The influence of the FID can be avoided by using an encoded reference. We therefore recommend the assessment of this influence of the FID for each displacement encoding with stimulated echoes protocol.
authors.affiliation: Department of Medical and Health Sciences, Linköping University, Linköping, Sweden. henrik.haraldsson@liu.se
authors.forename: Henrik
authors.initials: H
authors.lastname: Haraldsson
authors.forename: Andreas
authors.initials: A
authors.lastname: Sigfridsson
authors.forename: Hajime
authors.initials: H
authors.lastname: Sakuma
authors.forename: Jan
authors.initials: J
authors.lastname: Engvall
authors.forename: Tino
authors.initials: T
authors.lastname: Ebbers
mesh_terms: D000465:Algorithms; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity