To test whether cardiac multidetector CT (MDCT) perfusion imaging can accurately delineate an irreversibly damaged myocardium in animals with an occlusive myocardial infarction.

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).

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.

A perfusion defect on MDCT indicates the myocardial damage in an animal model with occlusive myocardial infarction.