title: Nonlinear image blending for dual-energy MDCT of the abdomen: can image quality be preserved if the contrast medium dose is reduced?
abstract: OBJECTIVE
  The objective of this study was to compare the image quality of a dual-energy nonlinear image blending technique at reduced load of contrast medium with a simulated 120-kVp linear blending technique at a full dose during portal venous phase MDCT of the abdomen.
  
  
  METHODS
  Forty-five patients (25 men, 20 women; mean age, 65.6 ± 9.7 [SD] years; mean body weight, 74.9 ± 12.4 kg) underwent contrast-enhanced single-phase dual-energy CT of the abdomen by a random assignment to one of three different contrast medium (iomeprol 400) dose injection protocols: 1.3, 1.0, or 0.65 mL/kg of body weight. The contrast-to-noise ratio (CNR) and noise at the portal vein, liver, aorta, and kidney were compared among the different datasets using the ANOVA. Three readers qualitatively assessed all datasets in a blinded and independent fashion.
  
  
  RESULTS
  Nonlinear blended images at a 25% reduced dose allowed a significant improvement in CNR (p < 0.05 for all comparisons), compared with simulated 120-kVp linear blended images at a full dose. No statistically significant difference existed in CNR and noise between the nonlinear blended images at a 50% reduced dose and the simulated 120-kVp linear blended images at a full dose. Nonlinear blended images at a 50% reduced dose were considered in all cases to have acceptable image quality.
  
  
  CONCLUSIONS
  The dual-energy nonlinear image blending technique allows reducing the dose of contrast medium up to 50% during portal venous phase imaging of the abdomen while preserving image quality.
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Erwin Rd, Box 3808, Durham, NC 27710.
authors.forename: Achille
authors.initials: A
authors.lastname: Mileto
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Ramirez-Giraldo
authors.forename: Daniele
authors.initials: D
authors.lastname: Marin
authors.forename: Marcela
authors.initials: M
authors.lastname: Alfaro-Cordoba
authors.forename: Christian D
authors.initials: CD
authors.lastname: Eusemann
authors.forename: Emanuele
authors.initials: E
authors.lastname: Scribano
authors.forename: Alfredo
authors.initials: A
authors.lastname: Blandino
authors.forename: Silvio
authors.initials: S
authors.lastname: Mazziotti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Ascenti
mesh_terms: D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D017711:Nonlinear Dynamics; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol
keywords: MDCT; contrast medium; dual-energy CT; linear blending; nonlinear blending