title: Real-time perfusion imaging with low mechanical index pulse inversion Doppler imaging.
abstract: OBJECTIVE
  We sought to determine how successful pulse inversion Doppler (PID) imaging would be in detecting myocardial perfusion defects during dobutamine stress echocardiography.
  
  
  BACKGROUND
  By transmitting multiple pulses of alternating polarity (PID) at a low mechanical index, myocardial contrast enhancement from intravenously injected microbubbles can be detected using real-time frame rates. Pulse inversion Doppler imaging was performed in 117 patients during dobutamine stress echocardiography by using an intravenous bolus of a perfluorocarbon-filled, albumin-(Optison: n = 98) or liposome- (Definity: n = 19) encapsulated microbubble and a mechanical index of <0.3. The visual identification of myocardial contrast defects and wall motion abnormalities was determined by blinded review. Forty of the patients had quantitative angiography (QA) performed to correlate territorial contrast defects with stenosis diameter >50%.
  
  
  RESULTS
  There was a virtual absence of signal from the myocardium before contrast injections in all patients. Bright myocardial opacification at peak stress was observed in at least one coronary artery territory at frame rates up to 25 Hz in 114 of the 117 patients during dobutamine stress echocardiography. Regional myocardial contrast defects at peak stress were observed in all 30 patients with >50% stenosis in at least one vessel (13 with single-vessel and 17 with multivessel disease). Contrast defects were observed in 17 territories subtended by >50% diameter stenosis that had normal wall motion at peak stress. Overall agreement between QA and myocardial contrast enhancement on a territorial basis was 83%, as compared with 72% for wall motion.
  
  
  CONCLUSIONS
  Pulse inversion Doppler imaging allows the detection of myocardial perfusion abnormalities in real-time during stress echocardiography and will further add to the quality and sensitivity of this test.
authors.affiliation: Department of Internal Medicine, University of Nebraska Medical Center, Omaha 68198-1165, USA. trporter@unmc.edu
authors.forename: T R
authors.initials: TR
authors.lastname: Porter
authors.forename: F
authors.initials: F
authors.lastname: Xie
authors.forename: M
authors.initials: M
authors.lastname: Silver
authors.forename: D
authors.initials: D
authors.lastname: Kricsfeld
authors.forename: E
authors.initials: E
authors.lastname: Oleary
mesh_terms: D000418:Albumins; D003287:Contrast Media; D017023:Coronary Angiography; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015150:Echocardiography, Doppler / Q000379:methods*; D025401:Echocardiography, Stress; D005260:Female; D005466:Fluorocarbons; D006801:Humans; D008297:Male; D008863:Microspheres; D008875:Middle Aged
chemical_list: D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons; C042852:perflutren