Dynamic multi-section CT imaging in acute myocardial infarction: preliminary animal experience

To evaluate the feasibility of myocardial first-pass perfusion imaging with multidetector CT (MDCT). In five pigs, myocardial infaction was induced by permanent balloon occlusion of the left anterior descending coronary artery. Dynamic contrast-enhanced MDCT (12×1.5 mm, 120 kV, 30 mAs, 64 acquisitions, 40 ml iopromide 370@4ml/s) and contrast-enhanced first-pass perfusion magnetic resonance (MR) imaging (TR 7.7 ms/TE 2.6 ms, 64 acquisitions, 0.05 mmol/kg Gd-DTPA) were performed. Finally, the animals were sacrificed, and the heart was excised and stained with triphenyltetrazolin-chloride (TTC). Maximum signal intensity (SImax), contrast material arrival time (CAT), wash-in time (Tmax) and slope were calculated from time-density/signal-intensity curves. The area of myocardial hypoperfusion was measured as the percentage of the left-ventricular area (%LV). Parameters were compared using Bland-Altman plots and Student's t-tests. The hypoperfused area on MDCT was 19.3±4.5%LV (MR imaging 17.2±4.0%LV). The mean size of infarction was 18.7±5.7%LV with TTC. Semiquantitative analysis of MR imaging and MDCT for SImax, Tmax and slope showed significant differences between normal and infarcted myocardium (P<0.05). No significant differences were found for CAT. MDCT and MR imaging both allowed for the differentiation of hypoperfused and normal myocardium. Results given in absolute values differed significantly between both imaging modalities (P<0.05). MDCT has the potential for visual and semiquantitative assessment of first-pass myocardial perfusion.