Detection of Myocardial Infarction Using Delayed Enhancement Dual-Energy CT in Stable Patients

The objective of our study was to explore whether delayed enhancement dual-energy CT (DECT) allows the detection of myocardial infarcts in stable patients. Patients with known or suspected coronary artery disease clinically referred for myocardial perfusion imaging using SPECT were prospectively included. All patients (n = 34) also underwent stress, rest, and delayed enhancement DECT on a DECT scanner. At SPECT, segments with myocardial infarction (MI) were defined as those with a summed rest score of ≥ 2 in two or more consecutive segments, and a diagnosis of MI was supported by wall motion abnormalities, clinical history, and ECG findings. Segments with MI were identified in 13 (38%), 15 (44%), and 14 (41%) patients using SPECT, perfusion CT, and delayed enhancement DECT, respectively. When combined SPECT and perfusion CT results were used as the reference standard, delayed enhancement DECT had a sensitivity, specificity, positive predictive value, and negative predictive value for the detection of MI of 91.7% (95% CI, 62-98%), 86.4% (95% CI, 65-97%), 78.6% (95% CI, 49-95%), and 95.0% (95% CI, 75-100%). At delayed enhancement DECT (40 keV), a signal attenuation higher than 161 HU had a sensitivity of 72% and a specificity of 79% for the detection of MI on a per-segment basis. The median signal attenuation of myocardial infarcts at 40 keV was 3.0 SDs (interquartile range, 1.3-4.0 SDs) above that of normal myocardium. In this study, delayed enhancement DECT allowed the detection of myocardial infarcts in stable patients.