title: Fully automatic, retrospective enhancement of real-time acquired cardiac cine MR images using image-based navigators and respiratory motion-corrected averaging.
abstract: Real-time imaging may be clinically important in patients with congestive heart failure, arrhythmias, or in pediatric cases. However, real-time imaging typically has compromised spatial and temporal resolution compared with gated, segmented studies. To combine the best features of both types of imaging, a new method is proposed that uses parallel imaging to improve temporal resolution of real-time acquired images at the expense of signal-to-noise ratio (SNR), but then produces an SNR-enhanced cine by means of respiratory motion-corrected averaging of images acquired in real-time over multiple heartbeats while free-breathing. The retrospective processing based on image-based navigators and nonrigid image registration is fully automated. The proposed method was compared with conventional cine images in 21 subjects. The resultant image quality for the proposed method (3.9+/-0.44) was comparable to the conventional cine (4.2+/-0.99) on a 5-point scale (P=not significant [n.s.]). The conventional method exhibited degraded image quality in cases of arrhythmias whereas the proposed method had uniformly good quality. Motion-corrected averaging of real-time acquired cardiac images provides a means of attaining high-quality cine images with many of the benefits of real-time imaging, such as free-breathing acquisition and tolerance to arrhythmias.
authors.affiliation: Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA. kellman@nih.gov
authors.forename: Peter
authors.initials: P
authors.lastname: Kellman
authors.forename: Christophe
authors.initials: C
authors.lastname: Chefd'hotel
authors.forename: Christine H
authors.initials: CH
authors.lastname: Lorenz
authors.forename: Christine
authors.initials: C
authors.lastname: Mancini
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Arai
authors.forename: Elliot R
authors.initials: ER
authors.lastname: McVeigh
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001185:Artificial Intelligence; D003199:Computer Systems; D003324:Coronary Artery Disease / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D009068:Movement; D009203:Myocardial Infarction / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012189:Retrospective Studies; D012680:Sensitivity and Specificity