Figure 7a. Myocardial infarction in the left anterior descending coronary artery in a 40-year-old man. (a) Short-axis delayed-enhancement image shows extensive hyperenhancement in the anterior wall and septum, which corresponds to an extensive infarction. Nonenhanced subendocardial areas (arrows) correspond to microvascular obstruction after acute infarction. (b, c) Color-coded maps superimposed on tagged MR images acquired in early systole (b) and end systole (c) show the regional extent of circumferential shortening. Contraction, indicated in blue, is evident mainly in the remote myocardial areas (arrowheads). In the infarcted region, virtually no contraction is evident, as is indicated by green; a slight myocardial lengthening, indicated by red, is evident in the area of microvascular obstruction (arrows in c).