Uptake of iodinated contrast material by the ischemically damaged myocardial cell.

Computerized transmission tomography has shown differential contrast enhancement of the area of ischemic damage after intravenous administration of iodinated contrast material. The current study performed in normal dogs and dogs with two-day-old and 30-day-old myocardial infarctions was intended to determine if the iodine accumulation is intracellular. Scanning electron microscopy with energy dispersive x-ray analysis detected iodine peaks associated with the cells in areas of ischemic damage, while iodine peaks were not detected in normal myocardium. Energy spectra in the area of ischemic damage showed a significant increase in the Na+ -K+ ratio compared to normal myocardium, consistent with the loss of cellular membrane integrity in this region. Results were similar for both two- and 30-day-old infarcts. These results indicate that iodinated contrast material attaches to the membrane of enters the ischemically damaged cell, but is virtually excluded from the normal myocardial cell. It may serve as a marker of myocardial cells which have lost cellular membrane integrity after an ischemic insult.