Abstract 10023: Comparison of Delayed Myocardial Contrast Enhancement during Dual Energy Computed Tomography in Acute Coronary Syndrome and Magnetic Resonance Imaging

Abstract

[Background] Delayed contrast enhancement of the myocardium during cardiac magnetic resonance imaging (MRI) is useful for diagnosing myocardial infarction and evaluating myocardial viability. Delayed myocardial contrast enhancement (DE) similar to that seen in cardiac MRI is observed in cardiac computed tomography (CT). SOMATOM Definition Flash (Siemens) is an advanced device equipped with 2 pairs of X-ray tubes and detectors that enable dual energy imaging using 2 types of energy. The present study was undertaken to compare the DE during CT scan (dual energy imaging technique) and MRI in patients with acute coronary syndrome.

[Methods] The study involved 12 patients (men/women = 10/2; mean age, 65.2 ± 8.5 years) with acute coronary syndrome who were hospitalized for emergency percutaneous coronary intervention (PCI), which resulted in successful reperfusion, between April 2010 and March 2012. CT and MRI were performed on each patient about 2 weeks after the onset of the disease. The devices used were Siemens Dual Source CT and GE 1.5T MRI. Delayed-phase imaging was initiated at 6 min with CT and 15 min with MRI. During CT, an additional 50 mL of the contrast material was intravenously injected slowly (0.2 mL/s) after coronary artery CT and delayed-phase imaging was performed. For MRI, the contrast material was injected at an ordinary dose level (0.2 mL/kg body weight). CT was performed using the helical imaging technique (pitch, 0.17-0.25) with 2 tubes (100 kV and 140 kV). Image reconstruction employed the Heart PBV (heart perfused blood volume). The volume of the myocardium showing DE was calculated as ∑ (DE area × slice thickness).

[Results] In all subjects, DE during MRI and CT were identical. Both the DE volume (MRI, 15,377.5 ± 9702.7 cm³ vs CT, 11,796.5 ± 9278.0 cm³, p = 0.0025) and the percentage of this volume relative to the entire myocardial volume (MRI, 14.6% vs CT, 12.7%, p = 0.0268) were significantly greater for MRI than for CT, but the DE volume correlated significantly between MRI and CT (p < 0.0001).

[Conclusion] Patients with acute coronary syndrome showed a good correlation in the delayed contrast enhancement of the myocardium during dual energy CT and MRI, which suggested that this imaging modality would be clinically useful.