A computer-based method for calculation of orbital floor fractures from coronal computed tomography scans.

PURPOSE: A computer program recently developed for the calculation of the orbital floor and fracture areas from coronal computed tomography (CT) scans was used in a study to evaluate the accuracy and ability of this new method. MATERIAL AND METHODS: The size of orbital floors and fabricated fractures in 14 dried, anatomic specimens were measured in coronal CT scans by 3 independent observers. Based on this data set, the orbital floor and fracture regions were calculated with the newly developed computer program. These calculated regions were then compared with a direct measurement of the specimens that had been obtained by digital photography. The accuracy of the computer-based calculations was assessed using Lin's concordance correlation coefficient. RESULTS: The size of the orbital floor (mean +/- SD) was found to be 5.21 +/- 0.39 cm(2) by direct measurement of the specimens and 5.30 +/- 0.52 cm(2) by calculation with the computer program. The region of the fracture (mean +/- SD) was 1.05 +/- 0.64 cm(2) by direct measurement and 1.01 +/- 0.62 cm(2) by computer calculation. The between-method mean difference (direct measurement minus computer based calculation) was -0.09 cm(2) (or 1.7% of mean orbital floor region) for orbital floor region and 0.04 cm(2) (or 3.8% of mean fracture region) for fracture region. CONCLUSIONS: This accurate and time-saving method is practicable for determining the size and location of orbital floor fractures. This calculation program can be advantageously applied in the clinical management of blowout fractures of the orbit.