title: Quantification of aortic stiffness using magnetic resonance elastography: Measurement reproducibility, pulse wave velocity comparison, changes over cardiac cycle, and relationship with age.
abstract: OBJECTIVE
  To assess MR elastography (MRE)-derived aortic shear stiffness (μMRE ) measurements for: 1) reproducibility, 2) comparison to pulse wave velocity, 3) changes over the cardiac cycle, and 4) relationship with age.
  
  
  METHODS
  Cardiac-gated aortic MRE was performed on 20 healthy volunteers (aged 20-73 years). For assessing reproducibility of stiffness measurements, scans were repeated per volunteer. MRE wave images were analyzed to obtain stiffness of the abdominal aorta across the cardiac cycle, and comparisons were made with subject age.
  
  
  RESULTS
  Analysis of concordance correlation coefficient between scans 1 and 2 showed that rc  = 0.86 (95% confidence interval, 0.77, 0.94) with P < 0.0001. Significantly higher μMRE was observed for all volunteers during end-systole when compared to end-diastole (P < 0.0001). μMRE increased with age; end-systolic stiffness demonstrated a relatively stronger correlation with age (r = 0.62, P = 0.003) when compared to end-diastolic stiffness (r = 0.51, P = 0.023); and the slopes of end-systole and end-diastole were found to be significantly different (P = 0.011). [Formula: see text] at end-systole and end-diastole correlated linearly with pulse wave velocity, with an r = 0.54 (P = 0.013) and r = 0.58 (P = 0.008), respectively.
  
  
  CONCLUSIONS
  The results of this study indicate that MRE-derived aortic shear stiffness measurements are robust (reproducible and comparable to similar techniques). Mean μMRE was higher during end-systole when compared to end-diastole. μMRE was found to increase with age and showed a stronger correlation with end-systolic stiffness than with end-diastolic stiffness.
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Kenyhercz
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Raterman
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.|Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Venkata Sita Priyanka
authors.initials: VS
authors.lastname: Illapani
authors.affiliation: Department of Internal Medicine, Division of Cardiovascular Medicine, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Dowell
authors.affiliation: Center for Biostatistics, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Xiaokui
authors.initials: X
authors.lastname: Mo
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.|Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.|Department of Internal Medicine, Division of Cardiovascular Medicine, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: White
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.|Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.|Department of Internal Medicine, Division of Cardiovascular Medicine, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Arunark
authors.initials: A
authors.lastname: Kolipaka
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000465:Algorithms; D001011:Aorta / Q000000981:diagnostic imaging* / Q000473:pathology*; D001012:Aorta, Abdominal / Q000473:pathology; D001783:Blood Flow Velocity; D003971:Diastole; D054459:Elasticity Imaging Techniques / Q000379:methods*; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D063177:Pulse Wave Analysis; D015203:Reproducibility of Results; D013599:Systole; D059289:Vascular Stiffness; D055815:Young Adult
keywords: MR elastography; MRE; aortic MRE; aortic stiffness; pulse wave velocity