A new computer tool for systematic evaluation of intracranial volume and its capacity to evaluate the result of the operation for metopic synostosis.

The aim of this project was to develop a tool for systematic evaluation of volumetric changes after surgery for craniosynostosis. A computer program using MATLAB was developed to measure total intracranial volume and frontal volume, anterior to the coronary sutures, by multiplying the area with slice thickness of each slice from just above foramen magnum to just beneath the vertex in CT examinations. The ratio between frontal volume and total volume was used for evaluation of the clinical result in 12 patients operated on for metopic synostosis. In 0.625 and 5 millimetre slices the coefficients of variation were 0.00049 and 0.00058, respectively, for measurements of total volume. The highest coefficient of variation was found in postoperative measurements of the frontal volume and was 0.014 in 0.625 millimetre slices. Measurements in 5 millimetre slices resulted in 3.8% ± 1.5% (mean ± SD) lower total volumes and 5.8% ± 5.3% lower frontal volumes than measurements in 0.625 millimetre slices. In patients operated on for metopic synostosis the ratio between frontal volume and total volume increased 25% ± 16% for patients operated on with cranioplasty in combination with a spring (n = 6) and 20% ± 13% for patients operated on with cranioplasty in combination with a bone transplant (n = 6). In summary, this study has developed a tool that can determine frontal and total intracranial volume with little variation. This tool can be used for systematic evaluation of the result of the operation for metopic synostosis.