title: Improvement in echocardiographic evaluation of left ventricular wall motion using still-frame parametric imaging.
abstract: BACKGROUND
  Conventional echocardiographic assessment of left ventricular wall motion is based on visual interpretation of dynamic images, which depends on readers' experience. We tested the feasibility of evaluating endocardial motion using still-frame parametric images.
  
  
  RESULTS
  In protocol 1, integrated backscatter images were obtained in 8 anesthetized pigs at baseline, 5, and 60 seconds after left anterior descending coronary occlusion and during reperfusion. Images from 1 cardiac cycle were analyzed offline to create a parametric image of local video intensity oscillations. Ischemia-induced changes were quantified by segmenting the parametric images and calculating regional pixel-intensity profiles. In protocol 2, parametric images were obtained from contrast-enhanced echocardiograms in 30 patients (18 with wall-motion abnormalities; 12 control subjects). "Gold standard" for wall motion was determined from independent interpretations of dynamic images made by 3 experienced reviewers. Dynamic images were independently classified by 3 inexperienced and 3 intermediate-level readers. Interpretation was then repeated in combination with parametric images. Parametric images showed a bright band in the area spanned by endocardial motion, which gradually decreased in brightness and thickness in the left anterior descending territory during coronary occlusion in all animals. In patients, the agreement with the gold standard correlated with the readers' experience (68% inexperienced, 87% intermediate) and significantly improved by adding parametric images (83% and 91%, respectively).
  
  
  CONCLUSIONS
  Parametric imaging provides a still-frame display of regional endocardial motion, sensitive to track ischemia-induced abnormalities. When combined with dynamic images, this technique improves the accuracy of the interpretation of wall motion, especially by less experienced echocardiographers.
authors.affiliation: Noninvasive Cardiac Imaging Laboratory, Medical Center, University of Chicago, 5841 S Maryland Avenue, Chicago, IL 60637, USA.
authors.forename: Enrico G
authors.initials: EG
authors.lastname: Caiani
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Korcarz
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: DeCara
authors.forename: Lynn
authors.initials: L
authors.lastname: Weinert
authors.forename: Keith A
authors.initials: KA
authors.lastname: Collins
authors.forename: Kirk T
authors.initials: KT
authors.lastname: Spencer
authors.forename: Victor
authors.initials: V
authors.lastname: Mor-Avi
mesh_terms: D000368:Aged; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D003287:Contrast Media