[Cardiac magnetic resonance imaging in patients with a suspected myocardial infarction and normal coronary arteries].

BACKGROUND

Patients hospitalized with suspected ST-segment elevation myocardial infarction (STEMI) who have normal coronary arteries (CAs) on invasive coronary angiography (ICA) may have an AMI or another acute cardiac disease that mimics it.

AIM

To evaluate the usefulness of cardiac magnetic resonance imaging (CMRI) for diagnosing conditions resembling AMI with normal CAs.

MATERIAL AND METHODS

We studied 424 consecutive patients admitted with suspected STEMI who underwent ICA. Those with normal CAs underwent CMRI involving cine-CMRI sequences to evaluate segmental wall motion, T2-weighted short-tau inversion-recovery imaging to detect oedema and delayed contrast enhancement (DCE) after gadolinium administration to identify necrosis/fibrosis. Patients with previous myocardial infarction were excluded.

RESULTS

Twenty-six patients (6.1%) had normal CAs. Definitive diagnosis after CMRI was acute myocarditis in 11 patients (42.3%) whose DCE was localized in the subepicardium or intramyocardially but not in the endocardium, AMI in nine patients (34.6%) who had subendocardial or transmural DCE, and Takotsubo cardiomyopathy (TCM) in six patients (23.1%), whose CMRI showed regional contractility abnormalities of the left ventricle and myocardial oedema but not DCE.

CONCLUSIONS

Cardiac magnetic resonance imaging allows a precise diagnosis of acute myocardial infarction in patients with angiographically normal coronary arteries.