title: Detection accuracy of condylar defects in cone beam CT images scanned with different resolutions and units.
abstract: OBJECTIVE
  To assess the impact of spatial resolution and cone beam CT (CBCT) unit on CBCT images for the detection accuracy of condylar defects.
  
  
  METHODS
  42 temporomandibular joints were scanned, respectively, with the CBCT units ProMax® 3D (Planmeca Oy, Helsinki, Finland) and DCT PRO (Vatech, Co., Ltd., Yongin-Si, Republic of Korea) at normal and high resolutions. Seven dentists evaluated all the test images with respect to the presence or the absence of condylar defects. Receiver operating characteristic curve analysis was employed to define the detection accuracy. Two-way analysis of variance was used to analyse the values under the receiver operating characteristic curves for the differences among imaging groups and observers. Intraobserver variation was analysed using the Wilcoxon test.
  
  
  RESULTS
  Macroscopic anatomy examination revealed that, of the 42 temporomandibular joint condylar surfaces, 18 were normal and 24 had defects on the surface of condyles. No significant differences were found between the images scanned with normal and high resolutions for both CBCT units ProMax 3D (p = 0.119) and DCT PRO (p = 0.740). Significant differences exist between image groups of DCT PRO and ProMax 3D (p < 0.05). Neither the inter- nor the intraobserver variability were significant.
  
  
  CONCLUSIONS
  The spatial resolution per se did not have an impact on the detection accuracy of condylar defects. The detection accuracy of condylar defects highly depends on the CBCT unit used for examination.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Z-L
authors.initials: ZL
authors.lastname: Zhang
authors.forename: X-q
authors.initials: XQ
authors.lastname: Shi
authors.forename: X-c
authors.initials: XC
authors.lastname: Ma
authors.forename: G
authors.initials: G
authors.lastname: Li
mesh_terms: D000704:Analysis of Variance; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008335:Mandibular Condyle / Q000000981:diagnostic imaging*; D008336:Mandibular Diseases / Q000000981:diagnostic imaging*; D015588:Observer Variation; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods*; D013701:Temporal Bone / Q000000981:diagnostic imaging; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging
keywords: cone-beam computed tomography; mandibular condyle; temporomandibular joint