一种新的三维CT测量方法在评价颅缝早闭头颅不对称性畸形中的应用

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

目的 拟创用一种新的三维CT测量方法对先天性颅缝早闭头颅不对称性畸形患者进行诊断分析和手术疗效评价;同时,探讨该测量方法、指标与传统方法、指标相比的优缺点及临床意义.方法 在传统的颅顶不对称指数（cranial vault asymmetry index,CVAI）的基础上提出一种改良的CVAI：前颅顶不对称指数（anterior cranial vault asymmetry index,ACVAI）及后颅顶不对称指数（posterior cranial vault asymmetry index,PCVAI）,重建6例颅缝早闭患儿头颅的三维影像,测量头颅指数（cephalic index,CI）、CVAI、ACVAI及PCVAI,对各指标间进行统计学分析对比,分析头颅不对称畸形程度,评价术后头颅对称性的改善效果.结果 6例颅缝早闭患儿,术前、术后ACVAI的差值与CVAI差值相比差异有统计学意义（P＜0.05）;而CVAI术前、术后测量值差异无统计学意义（P＞0.05）.结论 ACVAI、PCVAI与CVAI相比能更加准确的反映出头颅的不对称性畸形,有助于对畸形程度进行分级,对手术疗效行定量化评价.

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.