Multislice computed tomography and magnetic resonance imaging for the assessment of reperfused acute myocardial infarction.

OBJECTIVES

We evaluated the accuracy of in vivo delayed-enhancement multislice computed tomography (DE-MSCT) and delayed-enhancement magnetic resonance imaging (DE-MRI) for the assessment of myocardial infarct size using postmortem triphenyltetrazolium chloride (TTC) pathology as standard of reference.

BACKGROUND

The diagnostic value of DE-MSCT for the assessment of acute reperfused myocardial infarction is currently unclear.

METHODS

In 10 domestic pigs (25 to 30 kg), the circumflex coronary artery was balloon-occluded for 2 h followed by reperfusion. After 5 days (3 to 7 days), DE-MRI (1.5-T) was performed 15 min after administration of 0.2 mmol/kg gadolinium-DTPA using an inversion recovery gradient echo technique. On the same day, DE-MSCT (64-slice) was performed 15 min after administration of 1 gI/kg of iodinated contrast material. One day after imaging, hearts were excised, sectioned in 8 mm short-axis slices, and stained with TTC. Infarct size was defined as the hyperenhanced area on DE-MSCT and DE-MRI images and the TTC-negative area on TTC pathology slices. Infarct size was expressed as percentage of total slice area.

RESULTS

Infarct size determined by DE-MSCT and DE-MRI showed a good correlation with infarct size assessed with TTC pathology (R2 = 0.96 [p < 0.001] and R(2) = 0.93 [p < 0.001], respectively). The correlation between DE-MSCT and DE-MRI was also good (R2 = 0.96; p < 0.001). The relative difference in CT attenuation value of infarcted myocardium compared to remote myocardium was 191 +/- 18%. The relative MR signal intensity between infarcted myocardium and remote myocardium was 554 +/- 156%.

CONCLUSIONS

We demonstrated that DE-MSCT can assess acute reperfused myocardial infarction in good agreement with in vivo DE-MRI and TTC pathology.