title: Three-dimensional computed tomography imaging of the eustachian tube lumen in patients with patulous eustachian tube.
abstract: BACKGROUND
  The eustachian tube (ET) has a complicated anatomy, which is related to middle ear pathology. The anatomy of the ET has been well investigated in cadavers, but may not accurately reflect that in living subjects. Three-dimensional (3D) computed tomography (CT) was used to examine the ET in patients with patulous ET.
  
  
  METHODS
  The subjects were 35 patients (17 males, aged 59 +/- 16 years, and 18 females, aged 44 +/- 15 years) with patulous ET which could be continuously traced from the pharyngeal orifice to the tympanic orifice (53 ears). CT was performed in the sitting position at rest, followed by 3D reconstruction. The course of the ET from the middle ear to the pharynx was visualized in 3D surface images. Morphological measurements of the curvature angle (angle C) and the inclination angle (angle I) were determined from 3D coordinates on the CT images.
  
  
  RESULTS
  The full length of the ET could be visualized in most patients suffering from patulous ET in the sitting position. Angle C was 21.7 +/- 5.8 degrees in the patients aged <40 years (n = 20), which is significantly larger than 16.7 +/- 6.8 degrees in the patients aged >59 years (n = 18; Student's t test, p < 0.05). Angle I was 26.5 +/- 4.2 degrees in the patients aged <40 years (n = 20), also significantly larger than 21.6 +/- 5.8 degrees in the patients aged >59 years (n = 18; Student's t test, p < 0.05).
  
  
  CONCLUSIONS
  CT in the sitting position is a potential diagnostic tool of the ET and middle ear pathology.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan. toshitoshi330@orl.med.tohoku.ac.jp
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Oshima
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hori
authors.forename: Tetsuaki
authors.initials: T
authors.lastname: Kawase
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D000328:Adult; D000368:Aged; D004432:Ear, Middle / Q000000981:diagnostic imaging; D005064:Eustachian Tube / Q000000981:diagnostic imaging*; D005260:Female; D006311:Hearing Disorders / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000000981:diagnostic imaging; D011187:Posture; D014057:Tomography, X-Ray Computed / Q000379:methods*