Indirect intracranial volume measurements using CT scans: clinical applications for craniosynostosis

This paper describes a method for obtaining indirect intracranial volume measurements using CT scans with CTpak, a software package for quantitative analysis of CT scan data. The validity of this technique was confirmed by comparing direct measurement of the intracranial volume of five dry skulls with axial scans at 1.5- and 4-mm slice intervals to determine indirect volume. The indirect intracranial volume measurement technique was then used to compare preoperative and postoperative intracranial volume in 30 patients with craniosynostosis who underwent cranial vault and orbital osteotomies with reshaping and advancement. Our findings show that the suture release and simultaneous reshaping procedures usually carried out are, in fact, associated with increased intracranial volume. The observed intracranial volume gain is attributable to a combination of factors, including the surgical procedure carried out and ongoing growth. These factors are further modified by the diagnosis, age of the patient, and time interval between CT scans.