Accuracy and precision of spiral CT in the assessment of neoplastic lesions associated with the mandible

Rationale and Objectives. The purpose of this study was to determine the ac curacy (validity) and precision (reliability) of spiral computed tomographi c (CT) images by using film- and computer graphics-based measurements of si mulated neoplastic lesions associated with the mandible. Materials and Methods. Four cadaver heads, each with two simulated tumors c ontaining contrast medium positioned medial to the mandibles, were examined by using a subsecond spiral CT scanner. Data were transferred to film and to a computer workstation. With computer graphics data were analyzed by usi ng multiplanar reconstructed images. Linear measurements of the length, wid th, and depth of simulated tumors were made by two observers, twice each, o n the film scans by using manual calipers and on the multiplanar reconstruc ted images by using computerized measurements. The soft tissues were then r emoved from the cadavers and the same measurements made by using the same c alipers. Results. No statistically significant differences between computer graphics - or film-based measurements and physical measurements (P > .05) or between inter- and intraobserver measurements (P > .05) were found. Conclusion, The authors found high reproducibility of measurements for all dimensions. Spiral CT allows accurate computer graphics- and film-based mea surements of neoplastic lesions associated with the mandible.