title: XD-GRASP: Golden-angle radial MRI with reconstruction of extra motion-state dimensions using compressed sensing.
abstract: OBJECTIVE
  To develop a novel framework for free-breathing MRI called XD-GRASP, which sorts dynamic data into extra motion-state dimensions using the self-navigation properties of radial imaging and reconstructs the multidimensional dataset using compressed sensing.
  
  
  METHODS
  Radial k-space data are continuously acquired using the golden-angle sampling scheme and sorted into multiple motion-states based on respiratory and/or cardiac motion signals derived directly from the data. The resulting undersampled multidimensional dataset is reconstructed using a compressed sensing approach that exploits sparsity along the new dynamic dimensions. The performance of XD-GRASP is demonstrated for free-breathing three-dimensional (3D) abdominal imaging, two-dimensional (2D) cardiac cine imaging and 3D dynamic contrast-enhanced (DCE) MRI of the liver, comparing against reconstructions without motion sorting in both healthy volunteers and patients.
  
  
  RESULTS
  XD-GRASP separates respiratory motion from cardiac motion in cardiac imaging, and respiratory motion from contrast enhancement in liver DCE-MRI, which improves image quality and reduces motion-blurring artifacts.
  
  
  CONCLUSIONS
  XD-GRASP represents a new use of sparsity for motion compensation and a novel way to handle motions in the context of a continuous acquisition paradigm. Instead of removing or correcting motion, extra motion-state dimensions are reconstructed, which improves image quality and also offers new physiological information of potential clinical value.
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.
authors: Li
authors: L
authors: Feng
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.
authors: Leon
authors: L
authors: Axel
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.
authors: Hersh
authors: H
authors: Chandarana
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.
authors: Kai Tobias
authors: KT
authors: Block
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.
authors: Daniel K
authors: DK
authors: Sodickson
authors: Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York, USA.|Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.
authors: Ricardo
authors: R
authors: Otazo
mesh_terms: D000005:Abdomen; D000328:Adult; D054537:Atrioventricular Block / Q000503:physiopathology*; D055424:Cardiac-Gated Imaging Techniques; D003287:Contrast Media; D044962:Data Compression / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D055425:Respiratory-Gated Imaging Techniques; D018879:Ventricular Premature Complexes / Q000503:physiopathology*
chemical_list: D003287:Contrast Media
keywords: compressed sensing; free-breathing; golden-angle; motion compensation; radial sampling