PURPOSE: Craniosynostosis is surgically released at an early age for multiple reasons, including to allow the brain adequate room to grow. Evidence for the rapid early growth of intracranial volume comes from several studies. However, the results of these studies have been questioned as they often rely on a calculated approximation of intracranial volume or are based on a small series of direct volume measurements. The purpose of our study is to contribute a large series of direct intracranial volume measurements to establish a growth curve in healthy children.

METHOD: We retrospectively reviewed the CT scans of 123 children from 1 week to 6 years of age performed at the NewYork-Presbyterian Hospital in New York City. The scans were performed on otherwise healthy children who came to the pediatric emergency room for an evaluation of possible head trauma, and then had CT scans which were read as normal. Intracranial volumes were calculated with a semi-automated image segmentation technique and volume rendering software.

RESULTS: The accuracy of our volume calculations was first confirmed on 5 dry skulls in which volumes were indirectly and directly measured, and the difference between our indirect and direct measurements was found to have a mean of just 0.66%. The graph of intracranial
volumes versus age in our 123 children formed a logarithmically-shaped curve which will be presented. Our data showed that the intracranial volume of a normal infant doubles by 9 months of age, and triples by 6 years of age.

CONCLUSION: In this relatively large study using a proven, accurate technique to measure intracranial volumes in healthy children, we confirmed the rapid growth of a child's skull, with intracranial volume doubling from birth to 9 months of age, and tripling by the age of 6 years. These data thus strongly support the recommendation for early surgical intervention in children born with craniosysnostosis to help prevent restriction of brain growth.