title: Comparison of real-time and intermittent triggered myocardial contrast echocardiography for quantification of coronary stenosis severity and transmural perfusion gradient.
abstract: BACKGROUND
  Both intermittent triggered and real-time myocardial contrast echocardiography (MCE) have been proposed to detect impaired myocardial perfusion. We compared the ability of these 2 methods to quantify altered myocardial blood flow (MBF) and transmural distribution of MBF produced by graded coronary stenoses.
  
  
  RESULTS
  In 8 open-chest dogs, we created 4 graded left anterior descending coronary artery (LAD) stenoses: 3 levels of reduced adenosine hyperemia (non-flow-limiting at rest) and 1 grade of flow-limiting at rest. Real-time MCE was performed with SonoVue infusion using low-energy power pulse inversion (ATL) imaging, whereas ECG-gated intermittent triggered imaging used high energy at pulsing intervals from 1:1 to 1:10. LAD signal intensity (SI) was plotted versus time by real-time MCE and versus pulsing intervals by triggered MCE and was fitted to a 1-exponential function to obtain plateau SI (A) and the rate of SI rise (b). Visual detection of decreased opacification was equivalent by triggered and real-time MCE. Fluorescent microsphere-derived MBF ratio in LAD/left circumflex artery beds demonstrated close correlation with both real-time imaging (b, r=0.79; Axb, r=0.81) and triggered imaging (b, r=0.78; Axb, r=0.80). The endocardial/epicardial ratio of MBF in the LAD bed demonstrated closer correlation with the endocardial/epicardial ratios of b (r=0.71) and Axb (r=0.67) obtained by real-time than triggered imaging (b, r=0.42; Axb, r=0.52).
  
  
  CONCLUSIONS
  Real-time and triggered MCE are equivalent in their ability to identify coronary stenosis and quantify altered MBF.
authors.affiliation: Cardiovascular Division, University of California at San Diego, USA.
authors.forename: H
authors.initials: H
authors.lastname: Masugata
authors.forename: S
authors.initials: S
authors.lastname: Lafitte
authors.forename: B
authors.initials: B
authors.lastname: Peters
authors.forename: G M
authors.initials: GM
authors.lastname: Strachan
authors.forename: A N
authors.initials: AN
authors.lastname: DeMaria
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003199:Computer Systems; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D010477:Perfusion; D012720:Severity of Illness Index; D013223:Statistics as Topic