Application of a new three-dimensional CT measurement method in evaluating the cranial asymmetry of congenital craniosynostosis

Abstract

Objective To evaluate a modified cranial vault asymmetry index in measuring the asymmetry of the skull shape with congenital craniosynostosis,to assess the surgical outcome quantitatively,and to discuss its advantages and shortcomings by compared with the traditional measurement method:cranial vault asymmetry index (CVAI).Methods Based on the traditional cranial vault asymmetry index,anterior cranial vault asymmetry index (ACVAI) and posterior cranial vault asymmetry index (PCVAI) were proposed to be applied in the evaluation of surgical effect.CI,CVAI,ACVAI and PCVAI on the reconstructed three-dimentional CT images were measured and analysed statistically to evaluate the degree of the malformation and assess the operational effect.The new method was compared with traditional one.Results There was significant difference in CVAI and ACVAI between preoperative and postoperative three-dimensional measurement values,and ACVAI was more obvious among these six congenital craniosynostosis cases.Statistical analysis showed that the difference between preoperative ACVAI and postoperative ACVAI was statistically significant (P＜0.05).Conclusions The modified ACVAI and PCVAI can better describe the degree of the cranial vault asymmetry compared with CVAI.It is also a reliable index to assess the surgical effect quantitatively.In addition,it is conducive to rating the malformation and further study. Key words: Congenital craniosynostosis; Cranial asymmetry; Cranial vault asymmetry index (CVAI) ; Three-dimentional CT measurement