Detection of residual wall motion after sustained myocardial infarction bygated Tc-99(m)-tetrofosmin SPECT: a comparison with echocardiography

The differentiation of residual viability from necrotic myocardium in patie nts with a previously sustained myocardial infarction is important in decid ing indications for revascularization. Myocardial viability can be assessed by studying perfusion and regional wall motion. With gated single photon e mission computed tomography (SPECT), it is possible to augment SPECT perfus ion data with ventricular functional data both at a global and regional lev el. The aim of the study was to analyse the concordance between wall motion score derived by gated SPECT and echocardiography. Furthermore, the agreem ent between myocardial perfusion and left ventricular wall motion was analy sed with both techniques. We studied a homogenous group of 25 consecutive p atients with a previous myocardial infarction (MI) using both gated SPECT T c-99(m)-tetrofosmin myocardial perfusion imaging and two-dimensional echoca rdiography. Echocardiography was performed within 2 weeks of the gated SPEC T study. Both for gated SPECT and for echocardiography the left ventricle w as divided into seven regions per patient. For comparison, the gated SPECT regions were matched to the echocardiographic regions, resulting in a total of 175 regions. Prevalence of abnormal wall motion (akinetic or dyskinetic ) was 23% (39/171) for echocardiography and 21% (36/175) for gated SPECT (P = NS). There was a high agreement in wall motion score between echocardiog raphy and gated SPECT of 80% (136/171). The agreement between myocardial pe rfusion and myocardial wall motion was 82% (143/175) for gated SPECT and 76 % (130/171) for echocardiography (P = NS). Nineteen (34%) of the 56 regions with severely diminished or absent myocardial perfusion showed normal or h ypokinetic wall motion both by gated SPECT and echocardiography suggesting residual myocardial viability in malperfused regions. Our results suggest t hat, gated SPECT imaging is a reliable tool for the assessment of regional wall motion in post myocardial infarction patients. Furthermore, in patient s with a previous myocardial infarction gated SPECT imaging has the potenti al to detect preserved wall motion in regions with fixed perfusion defects, which might be indicative of residual myocardial viability. ( (C) 2001 Lip pincott Williams & Wilkins).