Magnetic resonance imaging of myocardial infarction in Kawasaki disease.

We performed magnetic resonance imaging in patients with Kawasaki disease following myocardial infarction to assess the usefulness of the technique in detecting myocardial infarction and coronary artery lesions. In six patients (group A), the interval after myocardial infarction was from 7 days to 7 months, and in five patients (group B), it was from 1 to 4 years. Imaging was performed with a superconducting magnet operating at 0.5 T with spin-echo sequence and ECG-gated multiple slices of 5 mm thickness. Myocardial signals were increased in group A, and the region of high signal intensity corresponded to the site of myocardial infarction. The signal intensity within the myocardium was homogeneous in five patients in group B. Coronary arteries were visualized in 20 of 22 instances. Signals within the coronary artery were observed in all 14 instances with poor contrast runoff from the coronary aneurysm, and 11 of these vessels showed high signal intensity. In all six instances in which large aneurysms with severe stenosis were present, signals in the coronary artery were increased. In contrast, high signal intensity in the coronary artery was not observed in five of six instances with good contrast runoff. Signals in the coronary arterial cavity and high signal intensity in the coronary artery persisted in five of six instances with turbulent coronary flow. The findings of increased coronary arterial signals suggested stagnant blood flow in the coronary aneurysm. In conclusion, magnetic resonance imaging was a useful modality for assessment of myocardial infarction and coronary artery lesions in Kawasaki disease.