title: Left and right ventricular kinetic energy using time-resolved versus time-average ventricular volumes.
abstract: To measure the effects of using time-resolved (TR) versus time-averaged (TA) ventricular segmentation on four-dimensional flow-sensitive (4D flow) magnetic resonance imaging (MRI) kinetic energy (KE) calculations.
  
  
  
  Right (RV) and left (LV) ventricular KE was calculated from 4D flow MRI data acquired at 3.0T in 10 healthy volunteers and five subjects with cardiac disease using TR and TA segmentation. KE was calculated from the mass of blood within the ventricles multiplied by the velocities squared. Differences in TR and TA KE and interobserver variability were quantified with Bland-Altman analysis.
  
  
  
  In healthy volunteers, peak systolic RV KE (KERV) were 4.89 ± 1.49 mJ using TR and 5.53 ± 1.62 mJ using TA segmentation (P = 0.016); peak systolic LV KE (KELV) were 3.29 ± 0.96 mJ and 4.16 ± 1.26 mJ (P = 0.005). Peak diastolic KERVwere 3.33 ± 0.90 mJ (TR) and 3.61 ± 1.12 mJ (TA) (P = 0.082), while peak diastolic KELVwere 4.90 ± 1.49 mJ and 5.31 ± 1.59 mJ (P = 0.044). In patient volunteers, peak systolic KERVwere 4.34 ± 3.78 mJ using TR and 4.88 ± 3.98 mJ using TA segmentation (P = 0.26); peak systolic KELVwere 4.39 ± 4.21 mJ and 4.36 ± 3.84 mJ (P = 0.91). Peak diastolic KERVwere 3.34 ± 2.08 mJ (TR) and 4.05 ± 1.12 mJ (TA) (P = 0.08), while peak diastolic KELVwere 4.34 ± 5.11 mJ and 4.06 ± 3.47 mJ (P = 0.75). Interobserver differences in KELVwere greater for TR than TA calculations; bias ranged from 3 ± 30% for TA peak systolic KELVto 36 ± 30% for TR peak diastolic KELV.
  
  
  
  Although qualitatively similar, KE values calculated through TA segmentation were consistently greater than TR KE, with differences more pronounced during systole and in the LV.
  
  
  
  2 J. Magn. Reson. Imaging 2017;45:821-828.
authors: Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors: Syed F
authors: SF
authors: Hussaini
authors: Department of Mechanical Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors: David R
authors: DR
authors: Rutkowski
authors: Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA.|Department of Mechanical Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors: Alejandro
authors: A
authors: Roldán-Alzate
authors: Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors: Christopher J
authors: CJ
authors: François
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity; D002648:Child; D004735:Energy Transfer; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D009200:Myocardial Contraction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D018754:Ventricular Dysfunction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D055815:Young Adult
keywords: 4D flow MRI; cardiac function; cardiac magnetic resonance; kinetic energy