title: Optimization of window settings for virtual monoenergetic imaging in dual-energy CT of the liver: A multi-reader evaluation of standard monoenergetic and advanced imaged-based monoenergetic datasets.
abstract: OBJECTIVE
  To evaluate optimal window settings for display of virtual monoenergetic reconstructions in third-generation dual-source, dual-energy computed tomography (DECT) of the liver.
  
  
  METHODS
  Twenty-nine subjects were prospectively evaluated with DECT in arterial (AP) and portal venous (PVP) phases. Three reconstructed datasets were calculated: standard linearly-blended (LB120), 70-keV standard virtual monoenergetic (M70), and 50-keV advanced image-based virtual monoenergetic (M50+). Two readers assessed optimal window settings (width and level, W/L), establishing a mean for each reconstruction which was used for a blinded assessment of liver lesions.
  
  
  RESULTS
  The optimal W/L for M50+ were significantly higher for both AP (W=429.3 ± 44.6 HU, L=129.4 ± 9.7 HU) and PVP (W=376.1 ± 14.2HU, L=146.6 ± 7.0 HU) than for LB120 (AP, W=215.9 ± 16.9 HU, L=82.3 ± 9.4 HU) (PVP, W=173.4 ± 8.9 HU, L=69.3 ± 6.0 HU) and M70 (AP, W=247.1 ± 22.2 HU, L=72.9 ± 6.8 HU) (PVP, W=232.0 ± 27.9 HU, L=91.6 ± 14.4 HU). Use of the optimal window setting for M50+ vs. LB120 resulted in higher sensitivity (AP, 100% vs. 86%; PVP, 96% vs. 63%).
  
  
  CONCLUSIONS
  Application of dedicated window settings results in improved liver lesion detection rates in advanced image-based virtual monoenergetic DECT when customized for arterial and portal venous phases.
authors.affiliation: Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Carlo N
authors.initials: CN
authors.lastname: De Cecco
authors.affiliation: Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States; Department of Radiological Sciences, Oncological and Pathological Sciences University of Rome "Sapienza", via Franco Faggiana 1668, 04100 Latina, Italy.
authors.forename: Damiano
authors.initials: D
authors.lastname: Caruso
authors.affiliation: Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
authors.affiliation: Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States; Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Julian L
authors.initials: JL
authors.lastname: Wichmann
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Ter Louw
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Perry
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Picard
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Schaefer
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
authors.forename: Leland W
authors.initials: LW
authors.lastname: Parker
authors.affiliation: Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States. Electronic address: andrewdhardie@gmail.com.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Hardie
mesh_terms: D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Dual Energy CT; Hepatocellular carcinoma; Liver; Monoenergetic; Window