title: Retrospectively gated intracardiac 4D flow MRI using spiral trajectories.
abstract: OBJECTIVE
  To develop and evaluate retrospectively gated spiral readout four-dimensional (4D) flow MRI for intracardiac flow analysis.
  
  
  METHODS
  Retrospectively gated spiral 4D flow MRI was implemented on a 1.5-tesla scanner. The spiral sequence was compared against conventional Cartesian 4D flow (SENSE [sensitivity encoding] 2) in seven healthy volunteers and three patients (only spiral). In addition to comparing flow values, linear regression was used to assess internal consistency of aortic versus pulmonary net volume flows and left ventricular inflow versus outflow using quantitative pathlines analysis.
  
  
  RESULTS
  Total scan time with spiral 4D flow was 44% ± 6% of the Cartesian counterpart (13 ± 3 vs. 31 ± 7 min). Aortic versus pulmonary flow correlated strongly for the spiral sequence (P < 0.05, slope = 1.03, R(2) = 0.88, N = 10), whereas the linear relationship for the Cartesian sequence was not significant (P = 0.06, N = 7). Pathlines analysis indicated good data quality for the spiral (P < 0.05, slope = 1.02, R(2) = 0.90, N = 10) and Cartesian sequence (P < 0.05, slope = 1.10, R(2) = 0.93, N = 7). Spiral and Cartesian peak flow rate (P < 0.05, slope = 0.96, R(2) = 0.72, N = 14), peak velocity (P < 0.05, slope = 1.00, R(2) = 0.81, N = 14), and pathlines flow components (P < 0.05, slope = 1.04, R(2) = 0.87, N = 28) correlated well.
  
  
  CONCLUSIONS
  Retrospectively gated spiral 4D flow MRI permits more than two-fold reduction in scan time compared to conventional Cartesian 4D flow MRI, while maintaining similar data quality.
authors: Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
authors: Sven
authors: S
authors: Petersson
authors: Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
authors: Andreas
authors: A
authors: Sigfridsson
authors: Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.|Division of Media and Information Technology, Department of Science and Technology/Swedish e-Science Research Centre, Linköping University, Linköping, Sweden.
authors: Petter
authors: P
authors: Dyverfeldt
authors: Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.|Department of Clinical Physiology and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors: Carl-Johan
authors: CJ
authors: Carlhäll
authors: Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.|Division of Media and Information Technology, Department of Science and Technology/Swedish e-Science Research Centre, Linköping University, Linköping, Sweden.
authors: Tino
authors: T
authors: Ebbers
mesh_terms: D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D001808:Blood Vessels / Q000502:physiology*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: 4D flow; phase-contrast MRI; cardiac flow; magnetic resonance imaging; retrospective cardiac gating; spiral