Diagnostic accuracy of limited-volume cone-beam computed tomography in the detection of periapical bone loss: 360° scans versus 180° scans
S. Lennon1, S. Patel1,2, F. Foschi1, R. Wilson3, J. Davies4, F. Mannocci1
Aim: To investigate the effect of reducing limited-
volume cone-beam computed tomographs arc of rota-
tion from 360° to 180° 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° 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 con- trols scored the presence/absence of bone 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° 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 con- trols scored the presence/absence of bone lesions.
Intra-examiner reliability was determined after
2weeks, 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 com- puted 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.
Keywords: 180°, CBCT, periapical bone loss, ROC,
sensitivity, specificity. 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 com- puted 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.
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