title: Diagnostic accuracy of limited-volume cone-beam computed tomography in the detection of periapical bone loss: 360° scans versus 180° scans.
abstract: OBJECTIVE
  To investigate the effect of reducing limited-volume cone-beam computed tomographs arc of rotation from 360° to 180° on the ability to diagnose small, artificially created apical lesions.
  
  
  METHODS
  Small, artificial apical bone lesions were prepared with a bur in the apical region of the distal root of ten mandibular first molars, in human dry mandibles. The jaws were scanned in a fixed position with limited-volume CBCT making a 360° and 180° arc of rotation, before and after each periapical lesion had been created. A 4 × 4 cm field of view was used at 90 kV, with a current of 4 mA. Ten examiners blinded to the scan parameters and controls scored the presence/absence of bone lesions. Intra-examiner reliability was determined after 2 weeks, reviewing half the data set. Statistical analyses with paired t-tests determined the diagnostic accuracy of the two modalities (360° vs. 180°) in terms of sensitivity, specificity, receiver operating characteristic area under the curve, positive predictive values and negative predictive values.
  
  
  RESULTS
  The mean values for sensitivity of the 360° and 180° scans were 0.91 and 0.89, respectively; their mean specificities were 0.73. No significant differences were reflected in the statistical analyses.
  
  
  CONCLUSIONS
  Both 360° and 180° cone-beam computed tomography scans yielded similar accuracy in the detection of artificial bone lesions. The use of 180° scans might be advisable to reduce the radiation dose to the patient in line with the ICRP guidance to use as low a dosage as reasonably achievable.
authors: Department of Conservative Dentistry, Dental Institute, King's College London, London, UK.
authors: S
authors: S
authors: Lennon
authors: S
authors: S
authors: Patel
authors: F
authors: F
authors: Foschi
authors: R
authors: R
authors: Wilson
authors: J
authors: J
authors: Davies
authors: F
authors: F
authors: Mannocci
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D019540:Area Under Curve; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003937:Diagnosis, Differential; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D010483:Periapical Diseases / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D012372:ROC Curve; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D012399:Rotation; D012680:Sensitivity and Specificity; D014092:Tooth Root / Q000000981:diagnostic imaging; D020390:Tooth Socket / Q000000981:diagnostic imaging