title: Myocardial first pass perfusion imaging with gadobutrol: impact of parallel imaging algorithms on image quality and signal behavior.
abstract: OBJECTIVE
  To implement parallel imaging algorithms in fast gradient recalled echo sequences for myocardial perfusion imaging and evaluate image quality, signal-to-noise ratio (SNR), contrast-enhancement ratio (CER), and semiquantitative perfusion parameters.
  
  
  METHODS
  In 20 volunteers, myocardial perfusion imaging with gadobutrol was performed at rest using an accelerated TurboFLASH sequence (TR 2.3 milliseconds, TE 0.93 milliseconds, flip angle [FA] 15 degrees) with GRAPPA, R=2. A nonaccelerated TurboFLASH sequence with similar scan parameters served as standard of reference. Artifacts were assessed qualitatively. SNR, CER, and CNR were calculated and semiquantitative perfusion parameters were determined from fitted SI-time curves.
  
  
  RESULTS
  Phantom measurements yielded significant higher SNR for nonaccelerated images (P<0.001). CER was equal; differences in CNR were statistically nonsignificant. The evaluation of semiquantitative perfusion parameters yielded significantly higher peak signal intensities in nonaccelerated images (P<0.001). Differences in maximum upslope were statistically nonsignificant. A qualitative examination of all images for artifacts by 2 board-certified radiologists yielded a significant reduction in dark rim artifacts with GRAPPA, R=2 (P<0.001).
  
  
  CONCLUSIONS
  The application of GRAPPA with an acceleration factor of R=2 leads to a significant reduction of dark rim artifacts in fast gradient recalled echo sequences.
authors.affiliation: Department of Clinical Radiology, Campus Grosshadern, Ludwig-Maximilians-University, Munich, Germany. daniel.theisen@med.uni-muenchen.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Theisen
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Wintersperger
authors.forename: Armin
authors.initials: A
authors.lastname: Huber
authors.forename: Olaf
authors.initials: O
authors.lastname: Dietrich
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schönberg
mesh_terms: D000328:Adult; D000465:Algorithms; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D009206:Myocardium; D009942:Organometallic Compounds; D010477:Perfusion; D019047:Phantoms, Imaging; D010865:Pilot Projects
chemical_list: D009942:Organometallic Compounds; C090600:gadobutrol