Abstract:

BACKGROUND: Delayed cardiac magnetic resonance imaging (MRI) is considered to be a promising noninvasive imaging to determine myocardial viability status. The commonly used contrast agent Gd-DTPA evaluation of survival myocardium is rather too high or too low, and irreversibility of myocardial infarction, but necrosis affinity contrast ECIII-600 can accurately reflect the area of necrotic myocardium. 
OBJECTIVE: To compare the diagnosis value of intracoronary injection of contrast medium affinity necrosis in evaluating myocardial viability in pigs with acute myocardial infarction.
METHODS: Twelve pigs were prepared for acute myocardial infarction models and were intracoronary injected 0.1 mmol/kg Gd-DTPA or 0.005 mmol/kg ECIII-600. Chest leads of ECG R wave trigger control, T1-weighted sequence with FAST, and delayed enhancement short axis surface scan imaging were performed. After scanning, the heart was cut along the short axis plane line into 6 mm sections and examined by triphenyl tetrazolium chloride (TTC) staining and light microscope. Relationship between infarct areas at the corresponding layer of MRI delayed enhancement and TTC staining was compared.
RESULTS AND CONCLUSION: Compared with TTC staining of myocardial infarction, the injection of Gd-DTPA enhanced delayed imaging 21% overestimated the infarcted area at 10 minutes, which was correspondence with the TTC staining at 30 minutes, followed by underestimation of the size of myocardial necrosis; Injection ECIII-600 MRI in the delayed necrosis showed strong and sustained contrast enhancement, strengthening area of myocardial infarction with TTC staining showed the same area. ECIII-600-enhanced MRI can accurately reflect the delay in acute myocardial infarct size. Gd-DTPA evaluation of myocardial infarct size is instable, and the observation time window is short. The cardiac MRI contrast agent should be completed within 1 hour after injection.