title: Accelerated motion corrected three-dimensional abdominal MRI using total variation regularized SENSE reconstruction.
abstract: OBJECTIVE
  Develop a nonrigid motion corrected reconstruction for highly accelerated free-breathing three-dimensional (3D) abdominal images without external sensors or additional scans.
  
  
  METHODS
  The proposed method accelerates the acquisition by undersampling and performs motion correction directly in the reconstruction using a general matrix description of the acquisition. Data are acquired using a self-gated 3D golden radial phase encoding trajectory, enabling a two stage reconstruction to estimate and then correct motion of the same data. In the first stage total variation regularized iterative SENSE is used to reconstruct highly undersampled respiratory resolved images. A nonrigid registration of these images is performed to estimate the complex motion in the abdomen. In the second stage, the estimated motion fields are incorporated in a general matrix reconstruction, which uses total variation regularization and incorporates k-space data from multiple respiratory positions. The proposed approach was tested on nine healthy volunteers and compared against a standard gated reconstruction using measures of liver sharpness, gradient entropy, visual assessment of image sharpness and overall image quality by two experts.
  
  
  RESULTS
  The proposed method achieves similar quality to the gated reconstruction with nonsignificant differences for liver sharpness (1.18 and 1.00, respectively), gradient entropy (1.00 and 1.00), visual score of image sharpness (2.22 and 2.44), and visual rank of image quality (3.33 and 3.39). An average reduction of the acquisition time from 102 s to 39 s could be achieved with the proposed method.
  
  
  CONCLUSIONS
  In vivo results demonstrate the feasibility of the proposed method showing similar image quality to the standard gated reconstruction while using data corresponding to a significantly reduced acquisition time. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.
authors.affiliation: King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.
authors.forename: Gastao
authors.initials: G
authors.lastname: Cruz
authors.affiliation: Centre for Medical Imaging, University College London, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Atkinson
authors.affiliation: Philips Research Hamburg, Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Buerger
authors.affiliation: King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.affiliation: King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.|Pontificia Universidad Católica de Chile, Escuela de Ingeniería, Santiago, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Prieto
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging*; D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology; D013997:Time Factors
keywords: abdominal MRI; motion correction; nonrigid motion; total variation; undersampling