Functional imaging in the assessment of myocardial infarction: MR imaging vs. MDCT vs. SPECT

To intraindividually compare magnetic resonance (MR) imaging, ECG-gated multi-detector spiral computed tomography (MDCT) and gated single photon emission computed tomography (SPECT) for the evaluation of global and regional myocardial function and the identification of myocardial perfusion abnormalities.

Nine patients (8 men; 55.1+/-8.9 years) with a history of myocardial infarction (MI) were included in this retrospective study. All patients had undergone segmented k-space steady state free precession MR imaging, (99m)Tc-MIBI gated myocardial perfusion SPECT and contrast enhanced ECG-gated 16-MDCT. Ventricular volumes and ejection fraction (EF) were calculated. Left ventricular (LV) wall motion at rest was analyzed. For SPECT and arterial phase MDCT perfusion abnormalities were assessed. Data was compared with Lin's concordance-correlation coefficient (rho(c)), Bland-Altman plots and kappa statistics.

For EF, there was an excellent concordance and correlation (rho(c)=0.99) between SPECT (EF=41.7+/-10.4%), MDCT (EF=42.2+/-11.1%), and MR imaging (EF=41.9+/-11.4%). Considering MR imaging as standard of reference, MDCT (kappa=0.86) is superior to SPECT (kappa=0.51) for the assessment of the regional wall motion at rest. There was a good agreement between SPECT and MDCT regarding the detection of perfusion abnormalities (kappa=0.62).

MDCT, MR imaging, and SPECT allow for the reliable assessment of global and regional left ventricular function in patients with a history of MI. MDCT also allows to some extent for the detection of perfusion abnormalities. With its potential to assess both, the coronary arteries as well as the myocardium, MDCT a promising modality for the comprehensive diagnostic work-up in patients with suspected myocardial ischemia.