The study of myocardial viability after myocardial infarction: Valve and limitations of magnetic resonance imaging compared with myocardial scintigraphy.

Abstract

International audienceAbstract: The aim of this study was to compare myocardial thickness measured by magnetic resonance imaging and quantified fixation of thallium. Twenty-one patients 61.2+/-11 years were investigated after myocardial infarction of the anterior wall in 8 cases, inferior in 10 cases, lateral in 2 cases and apical in one case. The mean angiographic ejection fraction was 46.5 +/- 19 %. Myocardial scintigraphy was performed after an exercise or pharmacological stress test and followed by a study of redistribution. The data was analysed by a quantitative method. Magnetic resonance imaging was performed with Vertical and horizontal long axis views in systole and diastole with division of the left ventricle into the same 12 regions. Three groups were defined according to fixation during redistribution. Group I : regions with fixation > 80% (n = 155) : group II : 60 to 80 % (n = 78); group III :fixation < 60 % (n = 19). All measurement of myocardial thickness were correlated (p < 0.01) with the fixation of thallium during redistribution. Systolic thickening. was significantly greater in group 1 (3.80 +/- 3.1 mm) than in groups II (2.20 +/- 3.8 mm) and III (1.56 +/- 2.4 mm) in which it was comparable. Regions in group III had systolic (8.61 +/- 3.53) and diastolic (6.89 +/- 3.3 mm) thicknesses significantly inferior to those in groups 1 (13.79 +/- 4.4 mm; 9.95 +/- 2.8 mm) and II (11.59 +/- 5.5 mm; 9.38 +/- 2.9 mm). Ninety per cent of regions with a systolic thickness of over 10 mm had fixation during redistribution of more than 60 %. This study shows that myocardial thickness is correlated to scintigraphic data. The systolic thickness over 10 mm would confirm the viability of a given region