Craniofacial skeletal measurements based on computed tomography: Part I. Accuracy and reproducibility.

Computed tomography (CT) is a useful modality for the management of craniofacial anomalies. A study was undertaken to assess whether CT measurements of the upper craniofacial skeleton accurately represent the bony region imaged. Measurements taken directly from five dry skulls (approximate ages: adults, over 18 years; child, 4 years; infant, 6 months) were compared to those from axial CT scans of these skulls. Excellent agreement was found between the direct (dry skull) and indirect (CT) measurements. The effect of head tilt on the accuracy of these measurements was investigated. The error was within clinically acceptable limits (less than 5 percent) if the angle was no more than +/- 4 degrees from baseline (0 degrees). Objective standardized information gained from CT should complement the subjective clinical data usually collected for the treatment of craniofacial deformities.