Accuracy of radiographic measurements using cone beam computer tomography

Abstract

Objective: To compare the accuracy of radiographic measurements using cone beam (CBCT) and helical computer tomography (CT). Method: Six pig ribs with soft tissues were wrapped by putty impression material with radiographic markers placed. Two CBCTs and CT machines were used. Vertical and horizontal dimensions of the ribs were measured using the default software and on processed CT film. The actual dimension of the ribs was measured directly by the digital caliper after sectioning and removal of the soft tissues. Differences between radiographic dimensions and the actual dimensions were tested by 2-way ANOVA followed by posh-hoc analysis.

Result: No differences were found between measurements made by CBCT and CT images using the default software (P>0.05). However, the measurements were significantly smaller than the true measurement (P<0.001, mean=0.3mm). On the other hand, measurements made on CT films were significantly larger than the true measurement (P<0.001, mean=0.5mm).

Conclusion: Both CBCT and CT are reliable for implant planning. It is advisable to perform planning using default software rather than making direct measurements on films.