Background -We evaluated whether contrast-enhanced multidetector computed tomography(CE-MDCT) might characterize myocardial infarct(MI) with patterns similar to those obtained by contrast-enhanced magnetic resonance(CE-MR)and studied the underlying mechanisms. Methods and Results -In vivo infarct characterization by CE-MDCT was shown to be feasible between 4 and 20 minutes after contrast injection in 7 pigs with MI. Subsequently, in 16 patients with acute MI and 21 patients with chronic MI, contrast patterns by CE-MDCT were related to CE-MR. Eighteen patients had hypoenhanced regions on early CE-MDCT images at the time of coronary imaging, and 34 patients had hyperenhanced regions on images acquired 10 minutes later. On a segmental basis, there was moderately good concordance of early hypoenhanced regions(92%, κ=0.54, P< 0.001) and late hyperenhanced regions(82%, κ=0.61, P< 0.001) between CE-MDCT and CE-MR. Absolute sizes of early hypoenhanced(6±16 versus 7±16 g, P=0.25) and late hyperenhanced(36±34 versus 31±40 g, P=0.14) regions were similar on CE-MDCT and CE-MR and were highly correlated(r=0.93, P< 0.001 and r=0.89, P< 0.001 respectively). In 8 retrogradely perfused infarctedrabbit hearts, contrast kinetics of iomeprol were similar to gadodiamide, ie, slow wash in(8.7±6.7 versus 1.2±0.3 minutes, P< 0.001) in infarct core and slow washout(20±12 versus 2.5±0.5 minutes, P< 0.001) in both infarct core and rim compared with the remote region. Conclusions -Because iodated contrast agents have similar kinetics in infarcted and noninfarcted myocardium as gadolinium DPTA, CE-MDCT can characterize acute and chronic MI with contrast patterns similar to CE-MR. CE-MDCT may thus provide important information on infarct size and viability at the time of noninvasive coronary imaging.
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