CARDIOVASCULAR MEDICINE Assessment of myocardial perfusion abnormalities by intravenous myocardial contrast echocardiography with harmonic power Doppler imaging: comparison with positron emission tomography

Background: Intravenous myocardial contrast echocardiography with harmonic power Doppler imaging (HPDI) enables assessment of myocardial perfusion. Its accuracy in comparison with positron emission tomography (PET), which is one of the most reliable clinical gold standards for myocardial perfusion, remains to be determined. Objective: To assess the ability of HPDI to identify myocardial perfusion abnormalities, using PET as a gold standard. Methods: 23 patients with myocardial infarction underwent HPDI. Images were obtained from the apical two and four chamber views at pulsing intervals of one to eight cardiac cycles with continuous infusion of Levovist (Schering, Germany). PET was done within two weeks of HPDI. The left ventricle was divided into 12 segments and myocardial opacification by HPDI and uptake of NH3 by PET in each segment was graded as normal, mildly reduced, or severely reduced. Results: Of the 276 segments examined, adequate image quality was obtained in 226 (82%) by HPDI; 50 segments were excluded because of inadequate image quality. There were more exclusions in the basal segments than in the mid or apical segments (p < 0.0001). Of the 226 segments analysed, overall concordance between HPDI and PET was 82% (κ = 0.70). In the apex, more segments were overestimated by HPDI than were underestimated (χ = 6.25, p = 0.012). Conclusions: HPDI and PET gave similar results in the assessment of myocardial perfusion abnormalities. However, poor image quality in the basal segments and overestimation of perfusion in the apical segments are current limitations of HPDI.