title: Self-navigated isotropic three-dimensional cardiac T2 mapping.
abstract: OBJECTIVE
  To implement and characterize an isotropic three-dimensional cardiac T2 mapping technique.
  
  
  METHODS
  A self-navigated three-dimensional radial segmented balanced steady-state free precession pulse sequence with an isotropic 1.7-mm spatial resolution was implemented at 3T with a variable T2 preparation module. Bloch equation and Monte Carlo simulations were performed to determine the influence of the heart rate, B1 inhomogeneity and noise on the T2 fitting accuracy. In a phantom study, the accuracy of the pulse sequence was studied through comparison with a gold-standard spin-echo T2 mapping method. The robustness and homogeneity of the technique were ascertained in a study of 10 healthy adult human volunteers, while first results obtained in patients are reported.
  
  
  RESULTS
  The numerical simulations demonstrated that the heart rate and B1 inhomogeneity cause only minor deviations in the T2 fitting, whereas the phantom study showed good agreement of the technique with the gold standard. The volunteer study demonstrated an average myocardial T2 of 40.5 ± 3.3 ms and a <15% T2 gradient in the base-apex and anterior-inferior direction. In three patients, elevated T2 values were measured in regions with expected edema.
  
  
  CONCLUSIONS
  This respiratory self-navigated isotropic three-dimensional technique allows for accurate and robust in vitro and in vivo T2 quantification.
authors.affiliation: Department of Radiology, CardioVascular Magnetic Resonance (CVMR), University Hospital (CHUV) and University (UNIL) of Lausanne, Lausanne, Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.
authors.forename: Ruud B
authors.initials: RB
authors.lastname: van Heeswijk
authors.forename: Davide
authors.initials: D
authors.lastname: Piccini
authors.forename: Hélène
authors.initials: H
authors.lastname: Feliciano
authors.forename: Roger
authors.initials: R
authors.lastname: Hullin
authors.forename: Juerg
authors.initials: J
authors.lastname: Schwitter
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016880:Anisotropy; D005260:Female; D006331:Heart Diseases / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 3D; T2 mapping; isotropic; myocardium; self-navigation