title: Improving the image quality in computed tomographic pulmonary angiography with dual-energy subtraction: a new application of spectral computed tomography.
abstract: OBJECTIVE
  The objectives of this study were to assess quantitative and subjective image quality in computed tomographic pulmonary angiography using dual-energy subtraction methods compared with those of the monochromatic images using optimal contrast-to-noise ratios and those of the routine polychromatic images and to select the best dual-energy subtraction method.
  
  
  METHODS
  A total of 1 routine polychromatic image, 3 sets of dual-energy subtraction images (DESIs), and 2 sets of monochromatic images with different optimal contrast-to-noise ratios from 30 patients were obtained. The signal intensity and noise were measured; signal-to-noise ratio and contrast-to-noise ratio (CNR) were calculated. The global subjective image quality was subjectively assessed.
  
  
  RESULTS
  The DESI 3 got the highest CNR and the DESI 1 got the second highest CNR. The DESI 1 got the highest global subjective image quality score. The 3 subtraction image sets got the highest score in visualization of the pulmonary artery branches.
  
  
  CONCLUSIONS
  Computed tomographic pulmonary angiography with dual-energy subtraction technique is feasible. The DESI 1 afforded the best balance between the quantitative analysis and the subjective evaluation.
authors.affiliation: From the Department of Radiology, Hua Dong Hospital of Fu Dan University, Shanghai, China.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Bai
authors.forename: Yibo
authors.initials: Y
authors.lastname: Sun
authors.forename: Lin
authors.initials: L
authors.lastname: Qi
authors.forename: Yanli
authors.initials: Y
authors.lastname: Yang
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Hua
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*