Multidetector-row Computed Tomographic Evaluation of Myocardial Perfusion in Reperfused Chronic Myocardial Infarction: Value of Color-coded Perfusion Map in a Porcine Model

We aimed to develop color-coded CT perfusion maps (CPM) of infarcted myocardium and assess the utility of CPM in evaluating ischemic heart disease on a cardiac multi-detector CT (MDCT) in a porcine reperfused-myocardial-infarction model. Myocardial infarctions were induced by 30 min occlusions of the proximal left anterior descending coronary artery (LAD) in 17 healthy adult female pigs. First-pass and 5 min-delayed cardiac MDCTs were performed after 4 weeks of LAD occlusion. Myocardial CPMs were obtained by using the CPM program. Triphenyltetrazolium chloride (TTC)-staining was performed on the cardiac specimens. We analyzed the intermodality agreement on the size and location of the myocardial infarctions. TTC staining revealed myocardial infarction in 16 of 17 pigs, and 15 of these (94%) showed matched infarcts on the CPM and first-pass images. The areas of perfusion deficit noted in early arterial phase images and CPM coincided exactly with the areas of poor TTC staining in 12 of 15 pigs (80%). In the three remaining pigs, the areas of poor TTC staining were larger than those of a perfusion deficit demonstrated by either early arterial phase images or CPM. The agreement between these tests is calculated to be moderate to good (k = 0.736, P < 0.05). Ten myocardial segments in 4 of the 15 pigs (27%) with hypoattenuated myocardium showed a delayed enhancement on the 5 min-delayed images. Contrast-enhanced MDCT was useful and accurate in detecting chronic myocardial infarction; CPM was helpful in visualizing the infarcted myocardium.