title: Ultrasonographic evaluation of sinusitis during microgravity in a novel animal model.
abstract: OBJECTIVE
  To develop an animal model of rhinosinusitis in microgravity, to characterize the behavior of intracavitary fluid in microgravity, and to assess the accuracy of ultrasonographic (US) diagnosis in microgravity.
  
  
  METHODS
  An animal model of acute sinusitis was developed in anesthetized swine by creating a window into a frontal sinus to allow unilateral catheter placement and injection of fluid. We performed US examinations in normal and microgravity environments on control and sinusitis conditions and recorded these for later interpretation.
  
  
  METHODS
  Henry Ford Hospital and the National Aeronautics and Space Administration (NASA) Microgravity Research Facility in Houston, Texas.
  
  
  METHODS
  Ground (normal-gravity) experiments were conducted on anesthetized swine (n = 4) at Henry Ford Hospital before the microgravity experiments (n = 4) conducted in the NASA Microgravity Research Facility.
  
  
  METHODS
  Ultrasound visualization of fluid cavity.
  
  
  RESULTS
  Results of bilateral US examinations before fluid injection demonstrated typical air-filled sinuses. After unilateral injection of 1 mL of fluid, a consistent air-fluid interface was observed on the catheterized side at ground conditions. Microgravity conditions caused the rapid (<10-second) dissolution of the air-fluid interface, associated with uniform dispersion of the fluid to the walls of the sinus. The air-fluid interface reformed on return to normal gravity.
  
  
  CONCLUSIONS
  The US appearance of fluid in nasal sinuses during microgravity is characterized in the large animal model. On the introduction of microgravity, the typical air-fluid interface disassociates, and fluid lining the sinus can be observed. Such fluid behavior can be used to develop diagnostic criteria for acute bacterial rhinosinusitis in the microgravity environment.
authors.affiliation: Department of Surgery, Henry Ford Hospital, Detroit, MI 48202-2689, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Benninger
authors.forename: Kellie
authors.initials: K
authors.lastname: McFarlin
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Hamilton
authors.forename: Ilan
authors.initials: I
authors.lastname: Rubinfeld
authors.forename: Ashot E
authors.initials: AE
authors.lastname: Sargsyan
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Melton
authors.forename: Michelle
authors.initials: M
authors.lastname: Moyhi
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McLaren
authors.forename: Scott A
authors.initials: SA
authors.lastname: Dulchavsky
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D012852:Sinusitis / Q000000981:diagnostic imaging*; D013552:Swine; D014463:Ultrasonography; D014893:Weightlessness