[The Role of First Pass and Delayed Contrast-Enhancement Magnetic Resonance Imaging in Patients with Myocardial Infarction].

OBJECTIVE:To evaluate the role of contrast-enhancement magnetic resonance imaging (CeMRI) in patients with myocardial infarction (MI).METHODS:There were twenty-three patients enrolled in this study. After dynamic observation, there were 20 patients who were diagnosed as MI. All those patients underwent coronary artery angiography and CeMRI. MRI was performed with a 1.5-T magnet (AVANTO, SIMENS). After tagged images were acquired, the patients received an intravenous bolus of 0.1 mmol/kg Gd-DTPA at a rate of 5 ml/s. A first-pass perfusion scan was acquired simultaneously with a bolus injection. A second bolus of 0.3 mmol/kg Gd-DTPA was given following the first-pass images. Delayed images were acquired 5 minutes after the second bolus by using an inversion-recovery prepared gated fast-gradient echo-pulse sequence.RESULTS:Hypoenhancement was seen in 20 patients at the first-pass perfusion at the myocardial infarction site, while hyperenhancement was seen at delayed CeMRI. Myocardial infarction area in delayed CeMRI was 16.58% +/- 9.73%, which was correlated positively with peak CK and cTnT (r = 0.821, P < 0.01 and r = 0.565, P < 0.05), respectively. The ejection fraction (EF) detected by MRI was 0.46 +/- 0.13, while the left ventricular EF (LVEF) detected by left ventriculography was 0.49 +/- 0.16. There was no difference between two parameters.CONCLUSIONS:CeMRI may play an important role in the diagnosis and prognosis of patients with MI.