Characterization of Acute and Chronic Myocardial Infarcts by Multidetector Computed Tomography

Abstract

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 infarcted rabbit 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.