Occlusive Myocardial Infarction: Cardiac CT Perfusion in a Rat Model

ABSTRACT

PURPOSE: To test whether cardiac multidetector CT (MDCT) perfusion imaging can accurately delineate an irreversibly damaged myocardium in animals with an occlusive myocardial infarction. MATERIALS AND METHODS: In 16 rats, the left anterior descending coronary arteries were ligated distal to its first diagonal artery after a thoracotomy. Thirty minutes after the procedure, 16-slice MDCT (Sensation 16, Siemens, Erlangen, Germany) was performed and delayed images were obtained up to 5 minutes after injecting the contrast agent (0.2 mL/100g, 0.5 mL/sec). Ten rats were re-examined one week later. After CT scanning, the rats were sacrificed and their hearts were extirpated for 2,3,5-triphenyltetrazolium chloride (TTC) histochemical staining. The stained slices were compared with the CT images. The CT number (HU) of the infarct and non-infarct areas were estimated from the contrast ratio (CR). RESULTS: The CT attenuation in the infarct area was significantly lower than that in the normal myocardium. Quantitative analysis of the CT attenuation revealed a significant difference in the CR and CT attenuation of the infarct and reference areas (0.48+/-0.12 vs 0.64+/-0.13, p<0.05, 163+/-46 HU vs 216+/-56 HU, p<0.05). However, there were no significant differences in the CT numbers between the infarct and non-infarct areas on the one-week follow-up. CONCLUSION: A perfusion defect on MDCT indicates the myocardial damage in an animal model with occlusive myocardial infarction.