title: Detection of myocardial perfusion in multiple echocardiographic windows with one intravenous injection of microbubbles using transient response second harmonic imaging.
abstract: OBJECTIVE
  The purpose of this study was to prove that transient response harmonic imaging could detect normal and abnormal myocardial perfusion in multiple echocardiographic windows with one intravenous injection of microbubbles in humans.
  
  
  BACKGROUND
  Myocardial ultrasound contrast can be produced from intravenous perfluorocarbon-exposed sonicated dextrose albumin, and ultrasound can be significantly improved by briefly suspending the interval between frame rates. Whether this contrast can noninvasively quantify myocardial perfusion in humans is unknown.
  
  
  METHODS
  In 28 patients, harmonic transient response imaging was used to image the heart in multiple different imaging planes after one intravenous injection of ultrasound contrast agent. Twenty-five of these 28 patients had a repeat injection during dipyridamole stress. In the primary view, the ultrasound transmission rate was one frame per cardiac cycle; in secondary and tertiary views, the transmission rate was once every multiple cardiac cycles. Regional myocardial contrast was visually assessed and quantified off-line. Quantitative rest thallium and dipyridamole stress sestamibi imaging was also performed.
  
  
  RESULTS
  Perfusion abnormalities were evident in the secondary and tertiary views only with one frame every multiple cardiac cycles. Regional peak myocardial videointensity (PMVI) correlated closely with regional tracer uptake in individual patients both at rest (r = 0.84) and during stress (r = 0.88). A PMVI ratio (abnormal region divided by the region with highest nuclear uptake) < 0.6 in any view had a 92% sensitivity and a 84% specificity in identifying a regional nuclear perfusion abnormality.
  
  
  CONCLUSIONS
  Transient response imaging produces myocardial contrast in multiple views with one intravenous injection of contrast agent and can accurately identify regional myocardial perfusion abnormalities.
authors.affiliation: University of Nebraska Medical Center, Omaha 68198-2265, USA. RPORTER@MAIL.UNMC.EDU
authors.forename: T R
authors.initials: TR
authors.lastname: Porter
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: D
authors.initials: D
authors.lastname: Kricsfeld
authors.forename: R W
authors.initials: RW
authors.lastname: Armbruster
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D004176:Dipyridamole; D004452:Echocardiography / Q000379:methods; D005080:Exercise Test; D005260:Female; D005466:Fluorocarbons; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D013010:Sonication; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi