Measuring Cranial Vault Volume With Three-Dimensional Photography

Abstract

The gold standard for measuring cranial vault volume is a computed tomography (CT) scan. Computed tomography scans in the pediatric population carry the significant risk of inducing a malignancy later in life. In a novel study, we show that a three-dimensional (3D) photograph can be used to measure and track cranial vault volume changes in craniosynostosis patients. In a study of adequate power as determined by pre hoc analysis, we demonstrate a greater than 0.91 correlation coefficient between volume as measured by CT and 3D photograph in more than 70 patients presenting to a tertiary craniofacial center (P < 0.001). Volume above a plane running through the lateral canthus (ex) and tragus (t) sag-ex-t on the digital 3D photograph differs from CT by a mean percentage difference of 31.9% (SD, 14.0%; 95% confidence interval, P < 0.0001). A linear regression model was used to determine the equation describing the relationship between volume as measured by 3D photograph and CT; with this equation, the absolute volume of the cranial vault is easily determined using only the 3D image. Interrater reliability is high (>0.99, ICC). The ability to measure cranial vault volume from the 3D photograph adds an important dimension to the complete and objective analysis of skull growth and postoperative change.