Pulse-inversion myocardial contrast echocardiography (MCE) identifies adenosine induced acoustic defects in the myocardium of patients with critical coronary stenoses

D T Chin, J C Cooke, J Hancock, M J Monaghan; King's College Hospital, London

Harmonic MCE detects changes in myocardial blood flow and volume during stress induced ischaemia. These changes are difficult to visualise and their detection requires complex data post processing. Pulse inversion (PI) imaging is a new technology that amplifies contrast signal-to-noise ratio and may magnify acoustic changes during myocardial ischaemia. We therefore assessed the acoustic intensity (AI) of images produced by the technique before/during vasodilator stress. Methods: 19 subjects with no previous infarction, 10 with lone angiographic LAD stenoses > 80%, 2 with lone moderate LAD stenoses and 7 with RCA and circumflex but no LAD disease, were studied. The coronary supply to each echocardiographic segment was graded. MCE was performed with the transpulmonary contrast agent Sonazoid (Nycomed-Amersham) and end-systolic triggered PI imaging on an ATL HDI-5000cv system. Linear myocardial and left ventricular (LV) AI was measured from digital loops of images using HDI-lab (ATL) software. % change in mean myocardial AI before and during adenosine was calculated with (%N) and without (%A) normalisation for LV AI. Qualitative analysis of myocardial AI and geometry was performed. Results: Data from 26 apical views, 71 mid and apical segments and 26 LV regions of interest showed adenosine induced falls in myocardial AI were higher in the territory of vessels with critical stenoses. LV AI before and during adenosine remained unchanged. Visual analysis showed inducible acoustic defects in 8/15 ischaemic and 0/12 non-ischaemic apical segments (p = 0.003). Conclusions: PI imaging detects 20–30% falls in AI during ischaemia that are sufficient in some cases to allow visual detection of inducible defects in nearfield myocardium. PI technology may therefore have the potential for real time visual assessment of myocardial ischaemia.

Atrioventricular plane displacement changes during pregnancy

N Kametas,¹ F McAuliffe,¹ J Hancock,² J Chambers,³ K …