title: Accelerated 3D echo-planar imaging with compressed sensing for time-resolved hyperpolarized13C studies.
abstract: To enable large field-of-view, time-resolved volumetric coverage in hyperpolarized13C metabolic imaging by implementing a novel data acquisition and image reconstruction method based on the compressed sensing framework.
  
  
  
  A spectral-spatial pulse for single-resonance excitation followed by a symmetric echo-planar imaging (EPI) readout was implemented for encoding a 72 × 18 cm2field of view at 5 × 5 mm2resolution. Random undersampling was achieved with blipped z-gradients during the ramp portion of the echo-planar imaging readout. The sequence and reconstruction were tested with phantom studies and consecutive in vivo hyperpolarized13C scans in rats. Retrospectively and prospectively undersampled data were compared on the basis of structural similarity in the reconstructed images and the quantification of the lactate-to-pyruvate ratio in rat kidneys.
  
  
  
  No artifacts or loss of resolution are evident in the compressed sensing reconstructed images acquired with the proposed sequence. Structural similarity analysis indicate that compressed sensing reconstructions can accurately recover spatial features in the metabolic images evaluated.
  
  
  
  A novel z-blip acquisition sequence for compressed sensing accelerated hyperpolarized13C 3D echo-planar imaging was developed and demonstrated. The close agreement in lactate-to-pyruvate ratios from both retrospectively and prospectively undersampled data from rats shows that metabolic information is preserved with acceleration factors up to 3-fold with the developed method. Magn Reson Med 77:538-546, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Geraghty
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Justin Y C
authors.initials: JY
authors.lastname: Lau
authors.affiliation: GE Healthcare, Toronto, Ontario, Canada.
authors.forename: Albert P
authors.initials: AP
authors.lastname: Chen
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Cunningham
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D066241:Carbon-13 Magnetic Resonance Spectroscopy / Q000379:methods*; D044962:Data Compression / Q000379:methods*; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007668:Kidney / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods; D009038:Motion; D019047:Phantoms, Imaging; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
chemical_list: D019344:Lactic Acid; D019289:Pyruvic Acid
keywords: acceleration; compressed sensing; echo-planar imaging; hyperpolarized 13C; metabolic imaging