title: Feasibility of spectral CT imaging for the detection of liver lesions with gold-based contrast agents - A simulation study.
abstract: OBJECTIVE
  To demonstrate the feasibility of gold-specific spectral CT imaging for the detection of liver lesions in humans at low concentrations of gold as targeted contrast agent.
  
  
  METHODS
  A Monte Carlo simulation study of spectral CT imaging with a photon-counting and energy-resolving detector (with 6 energy bins) was performed in a realistic phantom of the human abdomen. The detector energy thresholds were optimized for the detection of gold. The simulation results were reconstructed with the K-edge imaging algorithm; the reconstructed gold-specific images were filtered and evaluated with respect to signal-to-noise ratio and contrast-to-noise ratio (CNR).
  
  
  RESULTS
  The simulations demonstrate the feasibility of spectral CT with CNRs of the specific gold signal between 2.7 and 4.8 after bilateral filtering. Using the optimized bin thresholds increases the CNRs of the lesions by up to 23% compared to bin thresholds described in former studies.
  
  
  CONCLUSIONS
  Gold is a promising new CT contrast agent for spectral CT in humans; minimum tissue mass fractions of 0.2 wt% of gold are required for sufficient image contrast.
authors.affiliation: Helmholtz-Zentrum München, German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Marie
authors.initials: M
authors.lastname: Müllner
authors.affiliation: Helmholtz-Zentrum München, German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Schlattl
authors.affiliation: Helmholtz-Zentrum München, German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Hoeschen
authors.affiliation: Josef Lissner Laboratory for Biomedical Imaging, Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany. Electronic address: od@dtrx.net.
authors.forename: Olaf
authors.initials: O
authors.lastname: Dietrich
mesh_terms: D000465:Algorithms; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006046:Gold; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D006046:Gold
keywords: Contrast agent; Gold; K-edge imaging; Monte Carlo simulation; Spectral CT