CT attenuation ratio of myocardium and blood pool in the normal and infarcted canine heart.

The CT attenuation of the myocardium varies with the contrast medium concentration of the blood at steady state. The demonstration of myocardial infarcts depends on the differences of CT numbers within the myocardium. In order to make possible objective estimation and measurement of myocardial ischemia the normal regression between CT attenuation of the blood pool and the myocardium has been determined in 13 dogs. The relationship has been applied to 15 dogs with experimental infarcts examined with contrast enhanced CT. The results indicate that this method may be of value in identifying and sizing myocardial infarcts of different ages in patients.