Occlusive Acute Myocardial Infarct on 16 Multidetector-row Helical CT: An Experimental Study in Rabbits

ABSTRACT

PURPOSE: We wanted to evaluate the findings and diagnostic accuracy of MDCT for diagnosing occlusive acute myocardial infarction in rabbits. MATERIALS AND METHODS: Myocardial infarction was induced in 14 rabbits. MDCT was performed in the early and delay phases at 1 minute and 6 minutes, respectively, after intravenous contrast injection. The rabbits were sacrificed after scanning. The cardiac specimens were sliced and then stained with triphenyltetrazolium chloride (TTC). The agreement in the transmural extent of infarction between the MDCT scans and the TTC-stained specimens were analyzed by using kappa values. RESULTS: Acute myocardial infarction was found in 9 of 14 rabbits on the TTC-stained specimens and MDCT. The infarcted myocardium was demonstrated as a low-attenuation area on the early phase and as a central low-attenuation area with rim-like enhancement along the endocardial and pericardial sides of the myocardial wall on the delay phase. There was excellent agreement in the scores of the transmural extent of myocardial infarction between the TTC-stained specimens and the early phase scan (kappa value = 0.882, p = 0.000), and there was fair to good agreement between the TTC-stained specimens and the delay phase scan (kappa value = 0.439, p = 0.000). Microscopic examination of the cardiac specimens revealed necrosis of myocardial cells in the central portion and granulation tissue along the endocardial and pericardial sides of the necrotic myocardium. CONCLUSION: 16 slice MDCT scan was useful for the diagnosis of acute myocardial infarction. The early phase scan was more accurate than the delay phase scan for evaluating the transmural extent of myocardial infarction. Histopathologic examination suggested that the low-attenuation area on the delay phase might correspond to necrotic myocardium and the enhanced area might correspond to granulation tissue.