title: Diagnostic accuracy of cone-beam CT in the assessment of mandibular invasion of lower gingival carcinoma: comparison with conventional panoramic radiography.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of cone-beam CT in assessing mandibular invasion by lower gingival carcinoma and compare it with that of panoramic radiography.
  
  
  METHODS
  Fifty patients with squamous cell carcinoma of the lower gingiva who were examined by both panoramic radiography and cone-beam CT before surgery were included in this study. Five radiologists used a 6-point rating scale to independently evaluate cone-beam CT and panoramic images for the presence or absence of alveolar bone and mandibular canal involvement by tumor. Using the histopathogical findings as the gold standard, we calculated and compared the area under the receiver operating characteristic curve (Az value) and the sensitivity and specificity of the two imaging modalities.
  
  
  RESULTS
  In evaluations of both alveolar bone and mandibular canal involvement, the mean Az value for cone-beam CT (0.918 and 0.977, respectively) was significantly higher than that for panoramic radiography (0.793 and 0.872, respectively). The mean sensitivity for cone-beam CT (89% and 99%, respectively) was significantly higher than that for panoramic radiography (73% and 56%, respectively). There was no significant difference in the mean specificity. While cone-beam CT could provide high-resolution three-dimensional images, the image quality around the alveolar crest was often hampered by severe dental artifacts and image noise, resulting in difficulties in detecting subtle alveolar invasion.
  
  
  CONCLUSIONS
  Cone-beam CT was significantly superior to panoramic radiography in evaluating mandibular invasion by lower gingival carcinoma. Its diagnostic value in detecting subtle alveolar invasion, however, may be limited by severe dental artifacts and image noise.
authors.affiliation: Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549, Japan. momin.orad@tmd.ac.jp
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Momin
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okochi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Akiko
authors.initials: A
authors.lastname: Imaizumi
authors.forename: Ken
authors.initials: K
authors.lastname: Omura
authors.forename: Teruo
authors.initials: T
authors.lastname: Amagasa
authors.forename: Norihiko
authors.initials: N
authors.lastname: Okada
authors.forename: Naoto
authors.initials: N
authors.lastname: Ohbayashi
authors.forename: Tohru
authors.initials: T
authors.lastname: Kurabayashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D005887:Gingival Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008339:Mandibular Neoplasms / Q000000981:diagnostic imaging*; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging; D011862:Radiography, Panoramic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity