title: Nasolacrimal system aeration on computed tomographic imaging: effects of patient positioning and scan orientation.
abstract: OBJECTIVE
  To determine the impact of patient positioning and scan orientation on the appearance of air in the nasolacrimal drainage system on computed tomography (CT) imaging, and the repeatability of the observations.
  
  
  METHODS
  This was a retrospective analysis of CT images for 92 patients.
  
  
  RESULTS
  Air was found to be present more fully in the upright-position group as compared with the supine-position group. Comparing axial and coronal scan orientation, no difference in aeration was found, except for the nasolacrimal duct in the upright-position group.
  
  
  CONCLUSIONS
  Patient position should be accounted for in diagnostic conclusions and treatment decisions based on CT.
authors: Section Oculofacial Plastic and Reconstructive Surgery, Ohio University/OhioHealth, Columbus, OH, USA.
authors: Craig N
authors: CN
authors: Czyz
authors: Department of Medical Education, Mount Carmel Health Systems, Columbus, OH, USA.
authors: Thomas S
authors: TS
authors: Bacon
authors: Department of Ophthalmology, University of Michigan, Ann Arbor, MI, USA.
authors: Andrew W
authors: AW
authors: Stacey
authors: Department of Biology, Wittenberg University, Springfield, OH, USA.
authors: Eva N
authors: EN
authors: Cahill
authors: Department of Ophthalmology, William H Havener Eye Institute, Ohio State University Wexner Medical Center, Columbus, OH, USA.
authors: Bryan R
authors: BR
authors: Costin
authors: The Sinus Institute of Ohio, Dublin, OH, USA.
authors: Boris I
authors: BI
authors: Karanfilov
authors: Department of Ophthalmology, William H Havener Eye Institute, Ohio State University Wexner Medical Center, Columbus, OH, USA.
authors: Kenneth V
authors: KV
authors: Cahill
keywords: axial; coronal; nasolacrimal duct; nasolacrimal sac