title: Improved Discrimination of Myocardial Perfusion Defects at Low Energy Levels Using Virtual Monochromatic Imaging.
abstract: OBJECTIVE
  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.
authors.affiliation: From the Department of Cardiovascular Imaging, Diagnóstico Maipú, Buenos Aires, Argentina.
authors.forename: Patricia
authors.initials: P
authors.lastname: Carrascosa
authors.forename: Alejandro
authors.initials: A
authors.lastname: Deviggiano
authors.forename: Macarena
authors.initials: M
authors.lastname: de Zan
authors.forename: Carlos
authors.initials: C
authors.lastname: Capunay
authors.forename: Roxana
authors.initials: R
authors.lastname: Campisi
authors.forename: Gaston A
authors.initials: GA
authors.lastname: Rodriguez-Granillo
mesh_terms: D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*