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).

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).

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.

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.

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.