[Demonstration of an acute myocardial infarction by nuclear magnetic resonance: comparison with 2-dimensional echocardiography in localization of the necrotic area].

In order to evaluate the ability of magnetic resonance imaging (MRI) to detect acute myocardial infarction (AMI) in man, we studied 15 normal volunteers and 22 patients with a recent AMI (13.5 +/- 7.7 days, range 4-28). To establish the ability of MRI in localizing the site of infarction we also performed a comparison between the segments of the left ventricle showing evidence of AMI by MRI and those presenting wall motion abnormalities by 2-dimensional echocardiography. By using strict criteria and 2 imaging planes MRI proved to be a reliable technique for the detection of AMI. MRI correctly identified AMI in 20 out of 22 subjects (90.9%). The site of AMI appeared as an area of increased signal intensity on spin echo images, particularly evident on late echoes: 15 patients had MRI findings compatible with transmural AMI and 5 patients with non-transmural AMI. The site of AMI as detected by MRI closely correlated with that indicated by 2-dimensional echocardiography, thus showing that MRI is a reliable tool for AMI localization. We also observed that the number of left ventricular segments judged as infarcted by MRI was significantly higher than that showing wall motion abnormalities. As MRI correctly identified the presence of 2 subendocardial lesions, not detected by echocardiography, it is suggested that MRI may be superior to echocardiography in detecting non-transmural lesions and the lateral extension of a transmural infarct. Our data show that MRI is a reliable tool for the detection and location of recent AMI in man. In particular MRI can locate AMI with a precision similar to that offered by 2-dimensional echocardiography.