Postmortem imaging of antemortem myocardial ischaemia.

OBJECTIVES

To determine the minimum survival time for detection of antemortem myocardial ischaemia with postmortem imaging (PMI) techniques.

METHODS

Nine pigs underwent ligation of the left anterior descending (LAD) (8) and/or right coronary artery (RCA) branch (4), and were killed 30 min-6 h after ligation. PMI (MRI and CT angiography) was performed 2-55 h after euthanasia. Signal intensity of myocardial segments was measured. The hearts were removed, the coronary arteries injected to mark perfused segments, and sections submitted for histology.

RESULTS

MRI T2-weighted sequences showed the ischaemic area as hyperintense in 4/4 LAD ligations with ≥4 h of ischaemia but in 0/4 with <4 h. Histological evidence of ischaemia was present in 4/4 animals after 4 h. Right ventricular ischaemic myocardium was visible on MRI T2-weighted sequences after 6 h of ischaemia in one animal. CT angiography showed the occluded coronary artery in all cases.

CONCLUSIONS

Ischaemic lesions of the left ventricle, but not of the right, at least 4 h old can be detected as hyperintense areas on T2-weighted postmortem MRI. This technique is most sensitive in the first 24 h after death. Other sequences did not enhance detection.

KEY POINTS

• Left ventricular myocardial ischaemia/infarction can be demonstrated by postmortem imaging (PMI). • Ischaemia/infarction is better detected if survival time is at least 4 h. • Right ventricular ischaemia/infarction is not reliably detected by PMI. • Computed tomography angiography can demonstrate arterial occlusion.