title: Efficient method for volumetric assessment of peak blood flow velocity using 4D flow MRI.
abstract: To test the feasibility and effectiveness of using maximum intensity plots (MIPs) based on 4D flow magnetic resonance imaging (MRI) velocity data to assess systolic peak velocities in a cohort of bicuspid aortic valve (BAV) patients.
  
  
  
  4D flow MRI at 1.5T was performed on 51 BAV patients. MIPs were generated from the 4D flow MRI velocity data and used by two users to determine peak velocities in three regions of interest (ROIs): ascending aorta (AAo), aortic arch, and descending aorta. 4D flow MRI peak velocities in the AAo were compared to peak velocities recorded by 2D phase contrast MRI (2D PCMRI) in a subcohort of 36 patients and by Doppler echocardiography in a subcohort of 34 patients. 4D flow MRI peak velocities recorded by each observer were compared for all ROIs to test for interobserver variability.
  
  
  
  4D flow MRI recorded significantly higher velocities compared to 2D PCMRI (2.04 ± 0.71 m/s vs. 1.69 ± 0.79 m/s, 17.2% difference, P < 0.001) and similar velocities compared to Doppler echocardiography. There was excellent agreement between the observers, with a mean difference of 0.005 m/s and an intraclass correlation coefficient of 0.98.
  
  
  
  4D flow MRI velocity MIPs allow for efficient measurement of peak velocities in BAV patients with higher accuracy than 2D PCMRI and similar accuracy to Doppler echocardiography. J. Magn. Reson. Imaging 2016;44:1673-1682.
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rose
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.|Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Jarvis
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Chowdhary
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Allen
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.|Division of Pediatric Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Robinson
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.|Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.|Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Rigsby
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: Schnell
mesh_terms: D000293:Adolescent; D000465:Algorithms; D001021:Aortic Valve / Q000002:abnormalities* / Q000503:physiopathology; D000082882:Bicuspid Aortic Valve Disease; D001783:Blood Flow Velocity / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology*; D001811:Blood Volume Determination / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000503:physiopathology*; 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; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: 4D flow; MRI; bicuspid aortic valve; pediatric; phase contrast