title: Parametric detection and measurement of perfusion defects in attenuated contrast echocardiographic images.
abstract: OBJECTIVE
  Attenuation of radio frequency (RF) signals limits the use of contrast echocardiography. The harmonic-to-fundamental ratio (HFR) of the RF signals compensates for attenuation. We tested whether HFR analysis measures the left ventricular nonperfused area under simulated experimental attenuation.
  
  
  METHODS
  Radio frequency image data from short axis systolic projections were obtained from 11 open-chest dogs with left anterior descending or left circumflex coronary artery occlusion followed by left atrial bolus injection of a perflutren microbubble contrast agent. Clinical attenuation was simulated by calibrated silicone pads interposed between the epicardial surface and the transducer to induce mild (7-dB) and severe (14-dB) reduction of the backscattered RF signals. Harmonic-to-fundamental ratio values were calculated for each image pixel for 0-, 7-, and 14-dB attenuation conditions and reproducibly showed a "perfused area" and a "nonperfused area." A reference nonperfused area was obtained by manual delineation in high-quality contrast scans.
  
  
  RESULTS
  Correlations of the HFR-detected and manually outlined perfusion defect areas were R = 0.92 for 0 dB, R = 0.94 for 7 dB, and R = 0.90 for 14 dB; the mean difference was less than 0.36 cm(2) (negligible) in all 3 attenuation settings. Conclusions. Attenuation compensation by our HFR method allows precise measurement of myocardial perfusion defect areas in contrast scans with simulated high level of attenuation.
authors.affiliation: Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
authors.forename: Shiro
authors.initials: S
authors.lastname: Yoshifuku
authors.forename: Shigao
authors.initials: S
authors.lastname: Chen
authors.forename: Eileen
authors.initials: E
authors.lastname: McMahon
authors.forename: Josef
authors.initials: J
authors.lastname: Korinek
authors.forename: Akiko
authors.initials: A
authors.lastname: Yoshikawa
authors.forename: Izuru
authors.initials: I
authors.lastname: Ochiai
authors.forename: Partho P
authors.initials: PP
authors.lastname: Sengupta
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
mesh_terms: D000418:Albumins; D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D005466:Fluorocarbons; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D017202:Myocardial Ischemia / Q000150:complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
chemical_list: D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons