title: Assessment of left ventricular mass in mice: comparison between two-dimensional and m-mode echocardiography.
abstract: OBJECTIVE
  M-mode echocardiography has been used extensively for estimating left ventricular (LV) mass in mice, but accuracy is limited by its unidimensional nature. This study tested whether two-dimensional (2-D) echocardiographic measurement of LV mass using area-length and truncated ellipsoid methods overcomes this limitation.
  
  
  METHODS
  Twenty-five anesthetized FVB/N mice (Mus musculus) underwent high resolution (15 MHZ) two-dimensionally directed M-mode and 2-D echocardiography. End-diastolic epicardial and endocardial areas from short-axis views and the LV orthogonal long-axis views were measured, while LV mass was calculated by 2-D area-length and truncated ellipsoid methods. LV mass was calculated from M-mode using the uncorrected cube equation. Hearts were removed and weighed after completing the echocardiographic studies. The correlation and agreement between echocardiographic-determined LV mass and gravimetric LV weight were examined.
  
  
  RESULTS
  LV mass using the area-length method correlated better with autopsy LV weight (r = 0.87, slope = 0.87, standard error of the estimate [SEE] = 12.4 mg, P < 0.001) than M-mode echocardiography (r = 0.85, slope = 0.71, SEE = 11.1 mg, P < 0.001), and the degree of agreement (bias +/- 2 SD) was better (10.2 +/- 25.1 mg vs 13.1 +/- 25.8 mg, P = NS). Although 2-D truncated ellipsoid LV mass showed a good correlation with necropsy LV weight (r = 0.87, slope = 0.78, SEE = 11.0 mg, P < 0.001), the agreement between the truncated ellipsoid estimates and LV weight was less than that between M-mode and gravimetric LV mass.
  
  
  CONCLUSIONS
  The 2-D area-length method is an accurate method of LV mass determination in symmetrical ventricles and can be used as an alternative for in vivo measurement of LV mass in mice.
authors.affiliation: Department of Medicine, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44106-5038, USA.
authors.forename: Songsak
authors.initials: S
authors.lastname: Kiatchoosakun
authors.forename: Joseph
authors.initials: J
authors.lastname: Restivo
authors.forename: Darryl
authors.initials: D
authors.lastname: Kirkpatrick
authors.forename: Brian D
authors.initials: BD
authors.lastname: Hoit
mesh_terms: D000818:Animals; D004452:Echocardiography / Q000706:statistics & numerical data; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008297:Male; D051379:Mice; D015588:Observer Variation