title: Single-beat versus multibeat real-time 3D echocardiography for assessing left ventricular volumes and ejection fraction: a comparison study with cardiac magnetic resonance.
abstract: BACKGROUND
  Real-time 3-dimensional echocardiography (RT3DE) is superior to 2D echocardiography in assessing left ventricular (LV) volumes and ejection fraction (EF), but its feasibility is limited by multibeat acquisition, which requires an optimal breath-hold and a regular heart rhythm. We sought to evaluate the accuracy and feasibility of single- and 2-beat RT3DE for LV volume and EF assessment.
  
  
  RESULTS
  Sixty-six consecutive patients referred for cardiac magnetic resonance (CMR) underwent RT3DE and CMR on the same day. Of the 50 patients (age, 59+/-18 years; 68%men; 42% coronary artery disease; LVEF=49+/-14%; limits, 14% to 76%) with an adequate RT3DE image quality, accuracy for LV volumes and EF measurements of single- and 2-beat modalities were compared with the conventional 4-beat acquisition and CMR. Correlations with CMR for LV end-diastolic volume (161+/-59 mL, r=0.93 to 0.94) and end-systolic volume (86+/-56 mL, r=0.93 to 0.96) were excellent regardless of the number of cardiac cycles used. However, because of the low temporal resolution (7+/-2 volumes per second), single-beat underestimated LVEF (bias, -5+/-8%) with greater bias than 2-beat (bias, 1+/-6%, P<0.001) and 4-beat (bias, 3+/-7%, P<0.001) modalities. Interestingly, 2-beat provided accuracy similar to 4-beat for end-diastolic volume (bias, -17+/-21 mL versus -15+/-23 mL), end-systolic volume (bias, -9+/-16 mL versus -12+/-17 mL), and LVEF (bias, 1+/-6% versus 3+/-7%) measurements, but fewer stitching artifacts were observed with 2- than 4-beat modalities (3% versus 30%).
  
  
  CONCLUSIONS
  Compared with conventional multibeat acquisitions, 2-beat modality provides similar accuracy in LV volume and EF measurements and should be preferred due to fewer stitching artifacts. In contrast, the temporal resolution of single-beat modality appears insufficient to provide an accurate estimation of LVEF.
authors.affiliation: APHP, Henri Mondor University Hospital, Cardiovascular Department, and INSERM U841, 51 Av. de Lattre de Tassigny, Creteil, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Macron
authors.forename: Pascal
authors.initials: P
authors.lastname: Lim
authors.forename: Alexandre
authors.initials: A
authors.lastname: Bensaid
authors.forename: Julien
authors.initials: J
authors.lastname: Nahum
authors.forename: Caroline
authors.initials: C
authors.lastname: Dussault
authors.forename: Laurens
authors.initials: L
authors.lastname: Mitchell-Heggs
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Dubois-Randé
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Deux
authors.forename: Pascal
authors.initials: P
authors.lastname: Gueret
mesh_terms: D000704:Analysis of Variance; D016477:Artifacts; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology*; D013997:Time Factors