title: Accelerated and navigator-gated look-locker imaging for cardiac T1 estimation (ANGIE): Development and application to T1 mapping of the right ventricle.
abstract: OBJECTIVE
  To develop a method for high-resolution cardiac T1 mapping.
  
  
  METHODS
  A new method, accelerated and navigator-gated look-locker imaging for cardiac T1 estimation (ANGIE), was developed. An adaptive acquisition algorithm that accounts for the interplay between navigator gating and undersampling patterns well-suited for compressed sensing was used to minimize scan time. Computer simulations, phantom experiments, and imaging of the left ventricle (LV) were used to optimize and evaluate ANGIE. ANGIE's high spatial resolution was demonstrated by T1 mapping of the right ventricle (RV). Comparisons were made to modified Look-Locker imaging (MOLLI).
  
  
  RESULTS
  Retrospective reconstruction of fully sampled datasets demonstrated the advantages of the adaptive algorithm. For the LV, ANGIE measurements of T1 were in good agreement with MOLLI. For the RV, ANGIE achieved a spatial resolution of 1.2 × 1.2 mm(2) with a scan time of 157 ± 53 s per slice, and measured RV T1 values of 980 ± 96 ms versus 1076 ± 157 ms for lower-resolution MOLLI. ANGIE provided lower intrascan variation in the RV T1 estimate compared with MOLLI (P < 0.05).
  
  
  CONCLUSIONS
  ANGIE enables high-resolution cardiac T1 mapping in clinically reasonable scan times. ANGIE opens the prospect of quantitative T1 mapping of thin cardiovascular structures such as the RV wall.
authors: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.
authors: Bhairav B
authors: BB
authors: Mehta
authors: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.
authors: Xiao
authors: X
authors: Chen
authors: Department of Cardiology, University of Virginia, Charlottesville, Virginia, USA.
authors: Kenneth C
authors: KC
authors: Bilchick
authors: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.|Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.|Department of Cardiology, University of Virginia, Charlottesville, Virginia, USA.
authors: Michael
authors: M
authors: Salerno
authors: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.|Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.
authors: Frederick H
authors: FH
authors: Epstein
mesh_terms: D000328:Adult; D000465:Algorithms; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / 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
keywords: MOLLI; T1 mapping; cardiac MRI; compressed sensing; navigator gating; right ventricle