Inter- and intra-study reproducibility of contrast echocardiography for assessment of interventricular septal wall perfusion rate in humans.

Abstract

To assess inter- and intra-study reproducibility of myocardial contrast echocardiography (MCE) imaging for quantitative measurement of myocardial perfusion rate in humans in ambulatory setting. In 20 subjects, we performed 2 MCE tests 20-40 min apart on the same day under the same standardized protocol, and evaluated single-reader between-study and between-reading reproducibility of assessment of indicators of myocardial perfusion rate, such as the slope of video-intensity change k, and the factors A (peak video-intensity) and B (background video-intensity after bubble destruction) and the product k X A. The region of interest was placed at the mid-posterior interventricular septal wall visualized in apical 4-chamber view. In a sub-analysis, we evaluated indicators of myocardial perfusion rate comparing subjects with normal vs. those with subnormal ejection fraction (EF). Inter-study reproducibility of assessment of k was relatively low (intraclass correlation coefficient = 0.36), whereas intra-study reproducibility was fair (intraclass correlation coefficient = 0.61). The parameters k X A and B showed higher reproducibility than the k (inter- and intra-study intraclass correlation coefficients 0.64 and 0.75, 0.74 and 0.91, respectively). For reference, reproducibility data of the depth of the region of interest, of EF and CO were excellent. k and k X A were lower in subjects with low vs. those with normal EF. Only k and k X A were lower in subjects with subnormal than in those with normal EF. The MCE-derived indicator of myocardial perfusion rate k X A showed fairly good between-study and between-reading reproducibility.