Assessment of Myocardial Perfusion in Patients with Acute Myocardial Infarction : Myocardial Contrast Echocardiography Using Intravenous Infusion of Microbubbles
Background:Unlike 99mTc-Sestamibi, microbubbles used during myocardial contrast echocardiography
(MCE) exist only in the vascular space. Therefore, there may be a difference in the
pattern of myocardial perfusion between MCE and 99mTc-Sestamibi Single-Photon Emission
Computed Tomography (SPECT) in acute myocardial infarction (AMI). Objectives:The
purpose of this study was to assess myocardial perfusion using MCE with intravenous infusion
of perfluorocarbon-exposed sonicated dextrose albumin microbubbles (IV MCE), and to
compare it with SPECT and MCE with intracoronary injection of sonicated Hexabrix (IC MCE).
Methods:Seventeen patients with AMI (male 13, age 59.5±8.8 years, anterior MI 10) underwent
IV MCE at 8.1±3.7 days after onset. SPECT and IC MCE were also performed at 1.2±1.0
days and 2.0±1.5 days from IV MCE respectively. Any revascularization procedures were not
performed between three studies. Perfusion defect by three methods was scored semiquantitatively
as 1:normal perfusion, 0.5:moderate defect, and 0:severe defect at 16 segments of the
left ventricle. Results:1) Perfusion defect in infarction territory was detected in 15 patients
with SPECT, 12 patients with IV MCE and 11 patients with IC MCE. 2) Concordance of
perfusion score at each segment was 93% between IV MCE and IC MCE, 65% between IV MCE and SPECT, and 64% between IC MCE and SPECT. 3) With IV MCE, perfusion defect
was observed in all 32 segments which were considered as having defect (score 0 and 0.5) by IC
MCE. However, defect by IV MCE was found only in 31 out of 108 segments considered as
having defect by SPECT. Conclusion:In the assessment of myocardial perfusion in pts with
AMI, IV MCE and IC MCE showed similar results. However, there was some discrepancy in the
extent of perfusion defect between MCE studies and SPECT