Real-time perfusion imaging with low mechanical index pulse inversion Doppler imaging

OBJECTIVES We sought to determine how successful pulse inversion Doppler (P ID) imaging Would be in detecting myocardial perfusion defects during dobut amine 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. METHODS Pulse inversion Doppler imaging was performed in 117 patients durin g dobutamine stress echocardiography by using an intravenous bolus of a per fluorocarbon-filled, albumin-Optison: n = 98) or Liposome- (Definity: n = 1 9) encapsulated microbubble and a mechanical index of <0.3. The visual iden tification of myocardial contrast defects and wall motion abnormalities was determined by blinded review. Forty of the patients had quantitative angio graphy (QA) performed to correlate territorial contrast defects with stenos is diameter >50%. RESULTS There was a virtual absence of signal from the myocardium before co ntrast injections in all patients. Bright myocardial opacification at peak stress was observed in at least one coronary artery territory at frame rate s up to 25 Hz in 114 of the 117 patients during dobutamine stress echocardi ography. Regional myocardial contrast defects at peak stress were observed in all 30 patients with >50% stenosis in at least one vessel (13 with singl e-vessel and 17 with multivessel disease). Contrast defects were observed i n 17 territories subtended by >50% diameter stenosis that had normal wall m otion at peak stress. Overall agreement between QA and myocardial contrast enhancement on a territorial basis was 83%, as compared with 72% for wall m otion. CONCLUSIONS Pulse inversion Doppler imaging allows the detection of myocard ial perfusion abnormalities in real-time during stress echocardiography and will further add to the quality and sensitivity of this test. (J Atn Coil Cardiol 2001;37:748-53) (C) 2001 by the American College of Cardiology.