title: Novel methodology for echocardiographic quantification of cardiac shape.
abstract: BACKGROUND
  Left ventricular (LV) shape is a major determinant of cardiac physiology with important prognostic implications. Current techniques are limited in their ability to characterize shape. Regional curvature analysis is a recently developed method that is free of idealized shape assumptions and is applicable globally or regionally.
  
  
  OBJECTIVE
  To measure the change in regional curvature from diastole to systole to determine whether modifications of this methodology can be applied to study LV shape noninvasively, and to compare this method with other shape analysis methods.
  
  
  METHODS
  Seventeen normal dogs underwent transthoracic echocardiography. LV dimensions were measured at end-diastole and end-systole. LV endocardial outlines were traced from apical four-chamber views. LV short to long axis (D/L) ratios and eccentricity index (E) were calculated. Regional curvatures were determined using customized software. Reproducibility of regional curvature was also determined.
  
  
  RESULTS
  LV regional curvature values were consistent among animals at diastole and systole in all areas. Regional curvature showed divergence in different areas. D/L ratios showed a 7% decrease from diastole to systole, whereas E demonstrated a 10% increase. However, regional curvature exhibited a 39% change, suggesting that this methodology is more sensitive. Duplicate curvature values from same or different cardiac cycles were highly reproducible.
  
  
  CONCLUSIONS
  Quantitative regional curvature analysis can be applied with echocardiography to study LV shape. This methodology is more sensitive than current methods, is reproducible and may be applicable to the noninvasive study of shape changes in cardiac disease.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton.
authors.forename: S Y
authors.initials: SY
authors.lastname: Chan
authors.forename: G B
authors.initials: GB
authors.lastname: Mancini
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
authors.forename: D W
authors.initials: DW
authors.lastname: O'Brien
authors.forename: P W
authors.initials: PW
authors.lastname: Armstrong
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004285:Dogs; D004452:Echocardiography / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D008297:Male; D008838:Microcomputers; D009200:Myocardial Contraction; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D012984:Software; D013318:Stroke Volume; D014159:Transducers