title: Arrhythmia insensitive rapid cardiac T1 mapping pulse sequence.
abstract: OBJECTIVE
  To develop an arrhythmia-insensitive rapid (AIR) cardiac T1 mapping pulse sequence for quantification of diffuse fibrosis.
  
  
  METHODS
  An arrhythmia-insensitive cardiac T1 mapping pulse sequence was developed based on saturation recovery T1 weighting, which is inherently insensitive to heart rate and rhythm, and two single-shot balanced steady-state free precession image acquisitions with centric k-space ordering, where T1 calculation is inherently insensitive to T2 effects. Its performance against conventional cardiac T1 mapping based on inversion recovery (i.e., MOLLI) is compared. Phantom experiments (T1 ranging from 535 to 2123 ms) were performed with heart rate and rhythm simulated at 60 and 120 beats per minute (bpm) and arrhythmia using an external triggering device. Ten human subjects and 17 large animals were scanned precontrast and 5, 10, and 15 min after contrast agent administration.
  
  
  RESULTS
  Compared with the reference T1 mapping, AIR yielded lower normalized root-mean-square error than MOLLI (8% vs. 3%, respectively, at 60 bpm, 28% vs. 3%, respectively, at 120 bpm, and 22% vs. 3%, respectively, at arrhythmia). In vivo studies showed that T1 measurements made by MOLLI and AIR were strongly correlated (r = 0.99) but in poor agreement (mean difference = 161.8 ms, upper and lower 95% limits of agreements = 347.5 ms and -24.0 ms).
  
  
  CONCLUSIONS
  Our AIR pulse sequence may be clinically useful for assessment of diffuse myocardial fibrosis in patients.
authors.affiliation: Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA; CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Fitts
authors.forename: Elodie
authors.initials: E
authors.lastname: Breton
authors.forename: Eugene G
authors.initials: EG
authors.lastname: Kholmovski
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Dosdall
authors.forename: Sathya
authors.initials: S
authors.lastname: Vijayakumar
authors.forename: Kyung P
authors.initials: KP
authors.lastname: Hong
authors.forename: Ravi
authors.initials: R
authors.lastname: Ranjan
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.forename: Leon
authors.initials: L
authors.lastname: Axel
authors.forename: Daniel
authors.initials: D
authors.lastname: Kim
mesh_terms: D000328:Adult; D000465:Algorithms; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000473:pathology*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D009202:Cardiomyopathies / Q000150:complications / Q000473:pathology*; D004285:Dogs; D005260:Female; D005355:Fibrosis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: MRI; T1 mapping; arrhythmia; cardiac fibrosis; heart