title: Ventilation imaging of the paranasal sinuses using xenon-enhanced dynamic single-energy CT and dual-energy CT: a feasibility study in a nasal cast.
abstract: OBJECTIVE
  To show the feasibility of dual-energy CT (DECT) and dynamic CT for ventilation imaging of the paranasal sinuses in a nasal cast.
  
  
  METHODS
  In a first trial, xenon gas was administered to a nasal cast with a laminar flow of 7 L/min. Dynamic CT acquisitions of the nasal cavity and the sinuses were performed. This procedure was repeated with pulsating xenon flow. Local xenon concentrations in the different compartments of the model were determined on the basis of the enhancement levels. In a second trial, DECT measurements were performed both during laminar and pulsating xenon administration and the xenon concentrations were quantified directly.
  
  
  RESULTS
  Neither with dynamic CT nor DECT could xenon-related enhancement be detected in the sinuses during laminar airflow. Using pulsating flow, dynamic imaging showed a xenon wash-in and wash-out in the sinuses that followed a mono-exponential function with time constants of a few seconds. Accordingly, DECT revealed xenon enhancement in the sinuses only after pulsating xenon administration.
  
  
  CONCLUSIONS
  The feasibility of xenon-enhanced DECT for ventilation imaging was proven in a nasal cast. The superiority of pulsating gas flow for the administration of gas or aerosolised drugs to the paranasal sinuses was demonstrated.
  
  
  CONCLUSIONS
  • Ventilation of the paranasal sinuses is poorly understood.                         • Dual-energy CT ventilation imaging has been explored using phantom simulation.                         • Xenon can be seen in the paranasal sinuses using pulsating xenon flow.                         • Dual-energy CT uses a lower radiation dose compared with dynamic ventilation CT.
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilians University Hospital Munich, Klinikum Großhadern, Marchioninistr. 15, 81377, Munich, Germany. sven.thieme@med.uni-muenchen.de
authors.forename: Sven F
authors.initials: SF
authors.lastname: Thieme
authors.forename: Winfried
authors.initials: W
authors.lastname: Möller
authors.forename: Sven
authors.initials: S
authors.lastname: Becker
authors.forename: Uwe
authors.initials: U
authors.lastname: Schuschnig
authors.forename: Oliver
authors.initials: O
authors.lastname: Eickelberg
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Helck
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
mesh_terms: D005240:Feasibility Studies; D008953:Models, Anatomic; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging*; D012119:Respiration; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon
chemical_list: D014978:Xenon