Accuracy of chemically created periapical lesion measurements using limited cone beam computed tomography

Objectives: The aim was to assess the accuracy and reproducibility of measurements of chemically created periapical lesions using limited cone beam CT. Methods: Periapical lesions were chemically created in 18 mandibular cadaver teeth. Mandibles were dissected buccolingually using a bone-cutting burr. Diameters and depths were measured directly in the cross-sectional slices using a precision digital caliper. The cross-sectional slices were then embedded in wax, and cone beam CT images were acquired using a NewTom (R) 3G Plus scanner with both 6 inch and 9 inch fields of view (FOVs). Two oral radiologists measured the diameter and depth of periapical lesions on the cross-sectional images using the built-in measurement tools. Measurements were repeated after a 1 week interval. Inter-and intraobserver agreement was calculated by ANOVA. Regression analysis was used to test the correlation between the cone beam CT and digital caliper measurements. Results: No significant differences were found in diameter or depth measurements between or within observers or between 6 inch and 9 inch FOV images. Regression analysis of diameter and depth measurements made by direct caliper versus 6 inch or 9 inch FOV images revealed a high regression coefficient (for diameter: 6 inch FOV, R(2) = 94.6%; 9 inch FOV, R(2) = 94.8%; P<0.001; for depth: 6 inch FOV, R(2) = 99.3%; 9 inch FOV, R(2) = 99.3%; P<0.001) showing a strong linear relationship. For the diameter, the mean deviation from direct caliper measurements was 0.0625 mm and 0.08958 mm, respectively; for the 6 inch FOV and 9 inch FOV images, and for depth, the mean deviation was, respectively, -0.1001 mm and 0.09875 mm. Conclusions: Cone beam CT yielded highly accurate and reproducible results in the quantitative assessment of periapical lesions. Dentomaxillofacial Radiology (2010) 39, 95-99. doi: 10.1259/dmfr/85088069