Diagnostic accuracy of limited-volume cone-beam computed tomography in the detection of periapical bone loss: 360° scans versus 180° scans

Lennon S, Patel S, Foschi F, Wilson R, Davies J, Mannocci F. Diagnostic accuracy of limited- volume conebeam computed tomography in the detection of periapical bone loss: 360 degrees scans versus 180 degrees scans. International Endodontic Journal, 44, 1118-1127, 2011. Aim To investigate the effect of reducing limited-volume cone-beam computed tomographs arc of rotation from 360 degrees to 180 degrees on the ability to diagnose small, artificially created apical lesions. Methodology 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 degrees and 180 degrees arc of rotation, before and after each periapical lesion had been created. A 4 x 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 degrees vs. 180 degrees) 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 degrees and 180 degrees 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 degrees and 180 degrees cone-beam computed tomography scans yielded similar accuracy in the detection of artificial bone lesions. The use of 180 degrees 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.