title: Performances of low-dose dual-energy CT in reducing artifacts from implanted metallic orthopedic devices.
abstract: OBJECTIVE
  The objective was to evaluate the performances of dose-reduced dual-energy computed tomography (DECT) in decreasing metallic artifacts from orthopedic devices compared with dose-neutral DECT, dose-neutral single-energy computed tomography (SECT), and dose-reduced SECT.
  
  
  METHODS
  Thirty implants in 20 consecutive cadavers underwent both SECT and DECT at three fixed CT dose indexes (CTDI): 20.0, 10.0, and 5.0 mGy. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV, and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. In each group, the image quality of the seven monoenergetic images and of the SECT image was assessed qualitatively and quantitatively by visually rating and by measuring the maximum streak artifact respectively.
  
  
  RESULTS
  The comparison between SECT and OPTkeV evaluated overall within all groups showed a significant difference (p <0.001), with OPTkeV images providing better images. Comparing OPTkeV with the other DECT images, a significant difference was shown (p <0.001), with OPTkeV and 130-keV images providing the qualitatively best results. The OPTkeV images of 5.0-mGy acquisitions provided percentages of images with scores 1 and 2 of 36 % and 30 % respectively, compared with 0 % and 33.3 % of the corresponding SECT images of 10- and 20-mGy acquisitions. Moreover, DECT reconstructions at the OPTkeV of the low-dose group showed higher CT numbers than the SECT images of dose groups 1 and 2.
  
  
  CONCLUSIONS
  This study demonstrates that low-dose DECT permits a reduction of artifacts due to metallic implants to be obtained in a similar manner to neutral-dose DECT and better than reduced or neutral-dose SECT.
authors.affiliation: Department of Radiological Sciences, Institute of Radiology, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo A. Gemelli 8, 00168, Rome, Italy. laura.filograna@rm.unicatt.it.|Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland. laura.filograna@rm.unicatt.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Filograna
authors.affiliation: Department of Radiological Sciences, Institute of Radiology, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo A. Gemelli 8, 00168, Rome, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Magarelli
authors.affiliation: Department of Radiological Sciences, Institute of Radiology, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo A. Gemelli 8, 00168, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Leone
authors.affiliation: Research Centre for Health Technology Assessment, Department of Public Health, Section of Hygiene, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo F. Vito 1, 00168, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: de Waure
authors.affiliation: Research Centre for Health Technology Assessment, Department of Public Health, Section of Hygiene, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo F. Vito 1, 00168, Rome, Italy.
authors.forename: Giovanna Elisa
authors.initials: GE
authors.lastname: Calabrò
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
authors.forename: Tim
authors.initials: T
authors.lastname: Finkenstaedt
authors.affiliation: Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland.
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Thali
authors.affiliation: Department of Radiological Sciences, Institute of Radiology, Catholic University of Rome, School of Medicine, University Hospital "A. Gemelli", Largo A. Gemelli 8, 00168, Rome, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bonomo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019736:Prostheses and Implants; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Low-dose dual-energy computed tomography; Metallic artifact reduction; Monoenergetic extrapolation