title: Abdominal 4D flow MR imaging in a breath hold: combination of spiral sampling and dynamic compressed sensing for highly accelerated acquisition.
abstract: OBJECTIVE
  To develop a highly accelerated phase-contrast cardiac-gated volume flow measurement (four-dimensional [4D] flow) magnetic resonance (MR) imaging technique based on spiral sampling and dynamic compressed sensing and to compare this technique with established phase-contrast imaging techniques for the quantification of blood flow in abdominal vessels.
  
  
  METHODS
  This single-center prospective study was compliant with HIPAA and approved by the institutional review board. Ten subjects (nine men, one woman; mean age, 51 years; age range, 30-70 years) were enrolled. Seven patients had liver disease. Written informed consent was obtained from all participants. Two 4D flow acquisitions were performed in each subject, one with use of Cartesian sampling with respiratory tracking and the other with use of spiral sampling and a breath hold. Cartesian two-dimensional (2D) cine phase-contrast images were also acquired in the portal vein. Two observers independently assessed vessel conspicuity on phase-contrast three-dimensional angiograms. Quantitative flow parameters were measured by two independent observers in major abdominal vessels. Intertechnique concordance was quantified by using Bland-Altman and logistic regression analyses.
  
  
  RESULTS
  There was moderate to substantial agreement in vessel conspicuity between 4D flow acquisitions in arteries and veins (κ = 0.71 and 0.61, respectively, for observer 1; κ = 0.71 and 0.44 for observer 2), whereas more artifacts were observed with spiral 4D flow (κ = 0.30 and 0.20). Quantitative measurements in abdominal vessels showed good equivalence between spiral and Cartesian 4D flow techniques (lower bound of the 95% confidence interval: 63%, 77%, 60%, and 64% for flow, area, average velocity, and peak velocity, respectively). For portal venous flow, spiral 4D flow was in better agreement with 2D cine phase-contrast flow (95% limits of agreement: -8.8 and 9.3 mL/sec, respectively) than was Cartesian 4D flow (95% limits of agreement: -10.6 and 14.6 mL/sec).
  
  
  CONCLUSIONS
  The combination of highly efficient spiral sampling with dynamic compressed sensing results in major acceleration for 4D flow MR imaging, which allows comprehensive assessment of abdominal vessel hemodynamics in a single breath hold.
authors.affiliation: From the Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY 10029 (H.D., A.K., G.J., C.B., Y.C., B.T.); Healthcare Sector, Imaging & Therapy Division, Siemens, Erlangen, Germany (A.S.); and Department of Radiology and Biomedical Engineering, Feinberg School of Medicine, Northwestern University, Chicago, Ill (M.M.).
authors.forename: Hadrien
authors.initials: H
authors.lastname: Dyvorne
authors.forename: Ashley
authors.initials: A
authors.lastname: Knight-Greenfield
authors.forename: Guido
authors.initials: G
authors.lastname: Jajamovich
authors.forename: Cecilia
authors.initials: C
authors.lastname: Besa
authors.forename: Yong
authors.initials: Y
authors.lastname: Cui
authors.forename: Aurélien
authors.initials: A
authors.lastname: Stalder
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.forename: Bachir
authors.initials: B
authors.lastname: Taouli
mesh_terms: D000005:Abdomen / Q000098:blood supply*; D000328:Adult; D000368:Aged; D000465:Algorithms; D062485:Breath Holding; D003287:Contrast Media; D044962:Data Compression; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012984:Software
chemical_list: D003287:Contrast Media