title: Accelerating dual cardiac phase images using undersampled radial phase encoding trajectories.
abstract: A three-dimensional dual-cardiac-phase (3D-DCP) scan has been proposed to acquire two data sets of the whole heart and great vessels during the end-diastolic and end-systolic cardiac phases in a single free-breathing scan. This method has shown accurate assessment of cardiac anatomy and function but is limited by long acquisition times. This work proposes to accelerate the acquisition and reconstruction of 3D-DCP scans by exploiting redundant information of the outer k-space regions of both cardiac phases. This is achieved using a modified radial-phase-encoding trajectory and gridding reconstruction with uniform coil combination. The end-diastolic acquisition trajectory was angularly shifted with respect to the end-systolic phase. Initially, a fully-sampled 3D-DCP scan was acquired to determine the optimal percentage of the outer k-space data that can be combined between cardiac phases. Thereafter, prospectively undersampled data were reconstructed based on this percentage. As gold standard images, the undersampled data were also reconstructed using iterative SENSE. To validate the method, image quality assessments and a cardiac volume analysis were performed. The proposed method was tested in thirteen healthy volunteers (mean age, 30years). Prospectively undersampled data (R=4) reconstructed with 50% combination led high quality images. There were no significant differences in the image quality and in the cardiac volume analysis between our method and iterative SENSE. In addition, the proposed approach reduced the reconstruction time from 40min to 1min. In conclusion, the proposed method obtains 3D-DCP scans with an image quality comparable to those reconstructed with iterative SENSE, and within a clinically acceptable reconstruction time.
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; Electrical Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Karis
authors.initials: K
authors.lastname: Letelier
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Jesus
authors.initials: J
authors.lastname: Urbina
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Andía
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; Electrical Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Cristián
authors.initials: C
authors.lastname: Tejos
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; Electrical Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Irarrazaval
authors.affiliation: Division of imaging sciences, King's College London, London, UK.
authors.forename: Claudia
authors.initials: C
authors.lastname: Prieto
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: suribe@med.puc.cl.
authors.forename: Sergio
authors.initials: S
authors.lastname: Uribe
mesh_terms: D000328:Adult; D000465:Algorithms; D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D012119:Respiration
keywords: Dual phase; Radial phase encoding; View sharing; Whole-heart MRI