title: Localizing the mandibular canal on dental CT reformatted images: usefulness of panoramic views.
abstract: OBJECTIVE
  The aim of this study was to compare panoramic and paraxial views of dental CT reformatted images to detect the mandibular canal, and to evaluate the usefulness of the dental CT software function of "Outlining the Mandibular Canal in the Panoramic View".
  
  
  METHODS
  One hundred and fifty-five patients (310 sides), who underwent multi-slice computed tomography examination for pretreatment planning of dental implant were analyzed. After scanning, two types of dental CT reformatted image, panoramic and paraxial views were obtained. Two oral radiologists evaluated both views for the visibility of the mandibular canal using a 5-point rating scale: score 5, 100-80% visible, to score 1, 20-0% visible. The visibility scores of the two views were evaluated and compared by Wilcoxon's signed rank test.
  
  
  RESULTS
  The mean ± standard deviations of panoramic and paraxial views were 4.2 ± 1.1 and 3.5 ± 1.2, respectively, and the former was significantly higher than the latter (p < 0.001). On the basis of these results, we attempted to apply the function of "Outlining the Mandibular Canal in the Panoramic View" to cases with poor visibility of the canal (score 1, 2 or 3) on paraxial views. Consequently, we could reduce the number of such cases from 128 (41%) to 56 (18%).
  
  
  CONCLUSIONS
  The detectability of the mandibular canal was significantly higher in panoramic views than in paraxial views. Using the function of "Outlining the Mandibular Canal in the Panoramic View", the precision for identifying the canal on paraxial views was considered to be improved.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Takahashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kamiyama
authors.forename: Eiichi
authors.initials: E
authors.lastname: Honda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sumi
authors.forename: Tohru
authors.initials: T
authors.lastname: Kurabayashi
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011862:Radiography, Panoramic; D014057:Tomography, X-Ray Computed