Improved Discrimination of Myocardial Perfusion Defects at Low Energy Levels Using Virtual Monochromatic Imaging.

ABSTRACT

OBJECTIVES: The aim of this study was to explore the diagnostic performance of dual-energy computed tomography perfusion (DE-CTP) at different energy levels. METHODS: Patients with known or suspected coronary artery disease underwent stress and rest DE-CTP and single-photon emission computed tomography. Images were evaluated using monochromatic data, and perfusion defects were initially identified in a qualitative manner and subsequently confirmed using attenuation levels. RESULTS: Thirty-six patients were included. Sensitivity, specificity, positive predictive value, and negative predictive value of DE-CTP for the identification of perfusion defects were 84.1%, 94.2%, 77.3%, and 96.2%, respectively. Perfusion defects showed significantly lower attenuation than normal segments, with the largest differences among low energy levels (sensitivity of 96% and specificity of 98% using a cutoff value ≤ 153 Hounsfield units at 40 keV), progressively declining at the higher levels (P < 0.001). CONCLUSIONS: Dual-energy CTP at the lowest energy levels allowed improved discrimination of perfusion defects compared with higher energy levels.