title: Combined T2 -preparation and two-dimensional pencil-beam inner volume selection.
abstract: OBJECTIVE
  To improve coronary magnetic resonance angiography (MRA) by combining a two-dimensional (2D) spatially selective radiofrequency (RF) pulse with a T2 -preparation module ("2D-T2 -Prep").
  
  
  METHODS
  An adiabatic T2 -Prep was modified so that the first and last pulses were of differing spatial selectivity. The first RF pulse was replaced by a 2D pulse, such that a pencil-beam volume is excited. The last RF pulse remains nonselective, thus restoring the T2 -prepared pencil-beam, while tipping the (formerly longitudinal) magnetization outside of the pencil-beam into the transverse plane, where it is then spoiled. Thus, only a cylinder of T2 -prepared tissue remains for imaging. Numerical simulations were followed by phantom validation and in vivo coronary MRA, where the technique was quantitatively evaluated. Reduced field-of-view (rFoV) images were similarly studied.
  
  
  RESULTS
  In vivo, full field-of-view 2D-T2 -Prep significantly improved vessel sharpness as compared to conventional T2 -Prep, without adversely affecting signal-to-noise (SNR) or contrast-to-noise ratios (CNR). It also reduced respiratory motion artifacts. In rFoV images, the SNR, CNR, and vessel sharpness decreased, although scan time reduction was 60%.
  
  
  CONCLUSIONS
  When compared with conventional T2 -Prep, the 2D-T2 -Prep improves vessel sharpness and decreases respiratory ghosting while preserving both SNR and CNR. It may also acquire rFoV images for accelerated data acquisition.
authors.affiliation: Department of Radiology, University Hospital (CHUV) / University of Lausanne (UNIL), Lausanne, VD, Switzerland.|CardioVascular Magnetic Resonance (CVMR) research centre, Centre for BioMedical Imaging (CIBM), Lausanne, VD, Switzerland.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Coristine
authors.affiliation: Department of Radiology, University Hospital (CHUV) / University of Lausanne (UNIL), Lausanne, VD, Switzerland.|CardioVascular Magnetic Resonance (CVMR) research centre, Centre for BioMedical Imaging (CIBM), Lausanne, VD, Switzerland.
authors.forename: Ruud B
authors.initials: RB
authors.lastname: van Heeswijk
authors.affiliation: Department of Radiology, University Hospital (CHUV) / University of Lausanne (UNIL), Lausanne, VD, Switzerland.|CardioVascular Magnetic Resonance (CVMR) research centre, Centre for BioMedical Imaging (CIBM), Lausanne, VD, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
mesh_terms: D000465:Algorithms; D016477:Artifacts; D017023:Coronary Angiography / Q000379:methods; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D012016:Reference Values; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: 2D; T2-prep; adiabatic; coronary; inner volume