title: Endocardial surface area tracking for assessment of regional LV wall deformation with 3D speckle tracking imaging.
abstract: OBJECTIVE
  The aim of this experimental study was to validate area tracking by 3-dimensional (3D) speckle tracking imaging (STI) as a method to measure changes in regional left ventricular (LV) endocardial surface area with sonomicrometry and to assess the usefulness as a wall motion evaluation method compared with 1-dimensional strain parameters.
  
  
  BACKGROUND
  A 3D-STI allows for tracking a regional endocardial surface area during a cardiac cycle. Area tracking is a new concept that regional wall motion is quantified through the magnitude of deformation in an endocardial surface area.
  
  
  METHODS
  In each of 8 anesthetized sheep, sonomicrometry crystals were implanted on the endocardium at the LV mid and apical anterior walls. Area change ratio (ACR) that was a novel parameter obtained by area tracking was measured as percentage change in a segmental area during systole. Segmental longitudinal (LS) and circumferential strain (CS) also were measured by 3D-STI. The ACR, LS, and CS were compared with those by sonomicrometry at baseline and during pharmacological stress tests (dobutamine and propranolol infusion) and acute myocardial ischemia induced by occlusion of mid-left ascending artery.
  
  
  RESULTS
  The strong correlation was observed between ACR measurements by 3D-STI and those by sonomicrometry (Y = -4.20 + 0.84X, r = 0.87, p < 0.001). The ACR showed significant relations with both LS and CS (LS: Y = -15.1 + 1.73X, r = 0.73, p < 0.001; CS: Y = -5.85 + 1.06X, r = 0.79, p < 0.001). ACR showed significant differences among baseline, pharmacological stress, and acute myocardial ischemia. In contrast, LS and CS were reduced significantly during acute ischemia studies compared with those during the other studies; no differences were observed among baseline, propranolol infusion, and dobutamine infusion studies.
  
  
  CONCLUSIONS
  Area tracking by 3D-STI can estimate changes in LV regional area and might be promising for regional wall motion evaluations.
authors.affiliation: Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan. yo-seo@md.tsukuba.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Seo
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishizu
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Enomoto
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Sugimori
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D058665:Adrenergic beta-1 Receptor Agonists / Q000008:administration & dosage; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000465:Algorithms; D000818:Animals; D004195:Disease Models, Animal; D004280:Dobutamine / Q000008:administration & dosage; D019560:Echocardiography, Three-Dimensional; D004699:Endocardium / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000503:physiopathology; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted; D007262:Infusions, Intravenous; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015588:Observer Variation; D011237:Predictive Value of Tests; D011433:Propranolol / Q000008:administration & dosage; D015203:Reproducibility of Results; D012756:Sheep; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D058665:Adrenergic beta-1 Receptor Agonists; D000319:Adrenergic beta-Antagonists; D004280:Dobutamine; D011433:Propranolol