title: Power motion imaging can improve image quality in stress conditions with tachycardia.
abstract: BACKGROUND
  Stress echocardiographic studies are useful, but the evaluation of wall motion is sometimes suboptimal. The recently developed technique of power motion imaging can enhance mobile tissue definition.
  
  
  OBJECTIVE
  The study was undertaken to determine whether power motion imaging improves endocardial definition during tachycardia compared with conventional two-dimensional (2-D) imaging.
  
  
  METHODS
  Twenty pigs were studied during pacing rates of 100, 120, and 150 beats/min. We compared power motion imaging with standard 2-D imaging using systolic thickening visualization (STV) scores (3 = excellent definition of systolic thickening approximately 0 = total lack of visualization of systolic thickening) at each heart rate. We calculated the sum of the scores of 22 left ventricular segments as the overall STV score, and also calculated the sum of the scores in 10 parasternal segments and 12 apical segments separately.
  
  
  RESULTS
  The overall STV scores in both imaging methods were similar at 100 beats/min, but scores for power motion imaging were significantly higher than those of usual 2-D imaging at 120 and 150 beats/min. Using power motion imaging, the overall STV scores were similar as heart rate was increased; however, while using standard 2-D imaging, STV scores were significantly decreased as heart rate was increased. Findings were analyzed separately by parasternal and apical images. Especially in the parasternal images, the scores were significantly increased as heart rate was increased using power motion imaging.
  
  
  CONCLUSIONS
  We conclude that power motion imaging improves the detection of endocardial border in stress condition with tachycardia, and thus this modality is useful for stress echocardiography.
authors.affiliation: Division of Cardiology, University of California, San Francisco 94143-0214, USA.
authors.forename: M
authors.initials: M
authors.lastname: Nishino
authors.forename: H J
authors.initials: HJ
authors.lastname: Youn
authors.forename: D
authors.initials: D
authors.lastname: Gheorghevici
authors.forename: C
authors.initials: C
authors.lastname: Zellner
authors.forename: T M
authors.initials: TM
authors.lastname: Chou
authors.forename: K
authors.initials: K
authors.lastname: Sudhir
authors.forename: R F
authors.initials: RF
authors.lastname: Redberg
mesh_terms: D000818:Animals; D025401:Echocardiography, Stress / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D023421:Models, Animal; D013552:Swine; D013610:Tachycardia / Q000000981:diagnostic imaging*; D016277:Ventricular Function, Left