Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

• Published in: Imaging science in dentistry Vol. 44; no. 4; pp. 257 - 262
• Main Authors: Nikneshan, Sima, Aval, Shadi Hamidi, Bakhshalian, Neema, Shahab, Shahriyar, Mohammadpour, Mahdis, Sarikhani, Soodeh
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Academy of Oral and Maxillofacial Radiology 01.12.2014; 대한영상치의학회
• Subjects: Original; 치의학; Dimensional Measurement Accuracy; Dental Implants; Cone-Beam Computed Tomography
• ISSN: 2233-7822; 2233-7830
• DOI: 10.5624/isd.2014.44.4.257

This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0°), +10°, +12°, -12°, and -10° with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12°, -0.66 to -0.11 at -10°, -0.51 to +0.19 at 0°, -0.64 to +0.08 at +10°, and -0.64 to +0.1 at +12°. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Changing the slice orientation in the range of -12° to +12° reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.