title: Measurement of left ventricular mass by real-time three-dimensional echocardiography: validation against magnetic resonance and comparison with two-dimensional and m-mode measurements.
abstract: BACKGROUND
  The recent development of 3-dimensional (3D) surface detection algorithm of the endocardial and epicardial surfaces from real-time 3D echocardiographic (RT3DE) datasets allows direct semiautomated quantification of left ventricular mass (LVM). Our aims were to (1) evaluate the accuracy of RT3DE measurements of LVM using this algorithm against cardiac magnetic resonance (CMR) reference and (2) compare RT3DE LVM with conventional M-mode, 2-dimensional (2D), and RT3DE-guided biplane measurements.
  
  
  METHODS
  A total of 205 patients were studied in 2 protocols: (1) RT3DE and CMR imaging was performed on the same day in 55 subjects; (2) in an additional 150 subjects, RT3DE, 2D, and M-mode images were acquired. In both protocols, RT3DE endocardial and epicardial surfaces were semiautomatically identified at end diastole (QLab, Philips Medical Systems, Andover, MA) to calculate LVM. CMR, 2D, and M-mode-derived LVM were obtained using standard techniques.
  
  
  RESULTS
  A significant correlation (r = 0.95) was noted between RT3DE and CMR-derived LVM with a small bias of -2 g. M-mode-derived LVM measurements (175 +/- 64 g) were significantly larger than RT3DE LVM (123 +/- 39 g, bias: 52 g) with moderate correlation (r = 0.76). No significant differences in LVM were noted between 2D (125 +/- 42 g) and RT3DE values (bias: 1.2 g) with good correlation (r = 0.91, P < .001). However, the best correlation was noted between RT3DE and RT3DE-guided biplane LVM values (r = 0.95, P < .001, bias: -4.6 g). Intraobserver, interobserver variability, and test-retest variability of the RT3DE measurements were 9%, 12%, and 6%, respectively.
  
  
  CONCLUSIONS
  RT3DE imaging using the 3D surface detection algorithm allows accurate and reproducible measurements of LVM. RT3DE-guided biplane technique can be used as an accurate time-saving alternative in clinical practice.
authors.affiliation: Second Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nishikage
authors.forename: Victor
authors.initials: V
authors.lastname: Mor-Avi
authors.forename: Lissa
authors.initials: L
authors.lastname: Sugeng
authors.forename: Lynn
authors.initials: L
authors.lastname: Weinert
authors.forename: Hironi
authors.initials: H
authors.lastname: Nakai
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Salgo
authors.forename: Olivier
authors.initials: O
authors.lastname: Gerard
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang