title: Potential pitfalls of visualization of myocardial perfusion by myocardial contrast echocardiography with harmonic gray scale B-mode and power Doppler imaging.
abstract: OBJECTIVE
  The present study compared the regional variation of myocardial signal intensity in visualizing myocardial perfusion by myocardial contrast echocardiography (MCE) between harmonic gray scale and power Doppler imaging.
  
  
  METHODS
  MCE was performed in 12 patients by electrocardiographic (ECG)-gated intermittent triggered MCE with harmonic gray scale and power Doppler imaging following slow intravenous injection of 0.5 ml contrast agent (Optison). The interval between the ECG triggers (pulsing interval) was increased from every heart beat (1:1) to every 2 (1:2), 4 (1:4), and 8 (1:8) cardiac cycles to allow incremental microbubble (contrast agent) replenishment. The MCE images were recorded when attenuation produced by the left ventricular cavity was minimal. The background-subtracted videointensity was measured in 7 segments in an apical 4-chamber view: 3 (apical, mid, and basal) septal segments, 3 (apical, mid, and basal) lateral segments, and 1 apex segment (apical cap).
  
  
  RESULTS
  The background-subtracted videointensity for each segment was greater with the power Doppler than the gray scale imaging (p < 0.01). With the gray scale imaging, the background-subtracted videointensity in the basal septal segment demonstrated a negative value at all pulsing intervals, and the value (-9 +/- 13) was significantly lower than that (22 +/- 20) in the apical lateral segment at a pulsing interval of 1:8 (p < 0.01). With power Doppler imaging, the background-subtracted videointensity was high even in the basal septal segment (112 +/- 33), and no significant difference was observed among each segment.
  
  
  CONCLUSIONS
  The findings indicate that quantitative assessment of myocardial perfusion based upon background-subtracted video-intensity may be difficult in the far field with harmonic gray scale imaging although the attenuation is not apparent by visual analysis. Harmonic power Doppler is more sensitive for detecting basilar perfusion in the far field compared with harmonic gray scale imaging.
authors.affiliation: Second Department of Internal Medicine, Kagawa University, Kita, Japan. masugata@kms.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Masugata
authors.forename: Kazushi
authors.initials: K
authors.lastname: Yukiiri
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Takagi
authors.forename: Koji
authors.initials: K
authors.lastname: Ohmori
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Mizushige
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kohno
mesh_terms: D000368:Aged; D000418:Albumins / Q000008:administration & dosage; D003287:Contrast Media / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000473:pathology; D014741:Video Recording; D014796:Visual Perception
chemical_list: D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons