title: Free-breathing, motion-corrected, highly efficient whole heart T2 mapping at 3T with hybrid radial-cartesian trajectory.
abstract: OBJECTIVE
  To develop and test a time-efficient, free-breathing, whole heart T2 mapping technique at 3.0T.
  
  
  METHODS
  ECG-triggered three-dimensional (3D) images were acquired with different T2 preparations at 3.0T during free breathing. Respiratory motion was corrected with a navigator-guided motion correction framework at near perfect efficiency. Image intensities were fit to a monoexponential function to derive myocardial T2 maps. The proposed 3D, free breathing, motion-corrected (3D-FB-MoCo) approach was studied in ex vivo canine hearts and kidneys, healthy volunteers, and canine subjects with acute myocardial infarction (AMI).
  
  
  RESULTS
  Ex vivo T2 values from proposed 3D T2 -prep gradient echo were not different from two-dimensional (2D) spin echo (P = 0.7) and T2 -prep balanced steady-state free precession (bSSFP) (P = 0.7). In healthy volunteers, compared with 3D-FB-MoCo and breath-held 2D T2 -prep bSSFP (2D-BH), non-motion-corrected (3D-FB-Non-MoCo) myocardial T2 was longer, had a larger coefficient of variation (COV), and had a lower image quality (IQ) score (T2 = 40.3 ms, COV = 38%, and IQ = 2.3; all P < 0.05). Conversely, the mean and COV and IQ of 3D-FB-MoCo (T2 = 37.7 ms, COV = 17%, and IQ = 3.5) and 2D-BH (T2 = 38.0 ms, COV = 15%, and IQ = 3.8) were not different (P = 0.99, P = 0.74, and P = 0.14, respectively). In AMI, T2 values and edema volumes from 3D-FB-MoCo and 2D-BH were closely correlated (R(2) = 0.88 and 0.96, respectively).
  
  
  CONCLUSIONS
  The proposed whole heart T2 mapping approach can be performed within 5 min with similar accuracy to that of the 2D-BH T2 mapping approach.
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.|Department of Bioengineering, University of California, Los Angeles, California, USA.
authors.forename: Hsin-Jung
authors.initials: HJ
authors.lastname: Yang
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Behzad
authors.initials: B
authors.lastname: Sharif
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Jianing
authors.initials: J
authors.lastname: Pang
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.|Department of Bioengineering, University of California, Los Angeles, California, USA.
authors.forename: Avinash
authors.initials: A
authors.lastname: Kali
authors.affiliation: MR R&D, Siemens Healthcare, Los Angeles, California, USA.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Bi
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Cokic
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.|Department of Bioengineering, University of California, Los Angeles, California, USA.|Department of Medicine, University of California, Los Angeles, California, USA.
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
authors.affiliation: Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.|Department of Medicine, University of California, Los Angeles, California, USA.|Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Rohan
authors.initials: R
authors.lastname: Dharmakumar
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D004285:Dogs; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D009038:Motion; D009203:Myocardial Infarction / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D015656:Respiratory Mechanics
keywords: cardiac BOLD MRI; cardiac T2 mapping; fast imaging; myocardial edema