CT辅助下听眦线及鼻翼耳郭软骨下缘线对AC-PC平面的定位

摘要

目的 探讨在双源CT辅助下测量听眦线及鼻翼耳郭软骨下缘线对AC-PC平面的定位情况,达到更加准确的在成人体表勾绘出AC-PC平面.方法 通过测量我院326例接受立体定向手术的成人头颅的256层高分辨率双源CT扫描仪数据,输入手术计划系统,以获得听眦线及鼻翼耳郭软骨下缘线与AC-PC线在矢状平面投射夹角、前后联合间径长度、外耳道中点至平面垂直距离等常用参考值,以便获得扫描时精准的AC-PC平面.结果 采用平行于听眦线进行的CT 2 mm层厚的扫描中,AC-PC点全都存在同一层面中;在以平行于鼻翼耳郭软骨下缘线进行的CT 4 mm层厚的扫描中,AC-PC点全都存在同一层面中.听眦线与AC-PC的夹角为(1.6±0.7)°,相距(48.4±4.2)mm;鼻翼耳郭软骨下缘线与AC-PC的夹角(2.3±0.3)°,相距(15.8±2.8)mm,二者差异有统计学意义(P<0.05).结论 听眦线及鼻翼耳郭软骨下缘线在现有的CT扫描基线中与AC-PC连线平行度均较高,临床上实用性均较强;二者相比较,鼻翼耳郭软骨下缘线可作为更理想的立体定向功能神经外科的CT扫描基线.%Objective To study the measurement of AC-PC plane positioning between the Canthomeatal line and nosewing-auricle line assisted by CT,and to achieve delineating the AC-PC plane more accurately in the body surface.Methods By the 326 cases,measurement data who undergo stereotactic surgery of adult head in our hospital,to obtain the measurement of AC-PC line between the Canthomeatal line and nosewing-auricle line in the sagittal plane projection,the relative distance constant of AC-PC, the vertical distance in middle point of the external auditory canal to the AC-PC plane,in order to obtain the accurate AC-PC scan-ning plane.Results According the CT thick 2 mm layer scanning which parallelled to the canthomeatal line,AC-PC are all in the same level;according the CT thick 4 mm layer scanning which parallelled to the nosewing-auricle line,AC-PC are all in the same level.The average angle of canthomeatal line and AC-PC line is 1.6°±0.7°,the average length of AC-PC line is 48.4 mm±4.2 mm,the average angle of nosewing-auricle line and AC-PC line is 2.3°±0.3°,the average length of AC-PC line is 15.8 mm±2.8 mm,there are some obvious statistical difference between the two lines(P <0.05 ).Conclusion In the existing CT baseline,the clinical practicitabily of canthomeatal line and nosewing-auricle line are strong,nosewing-auricle line can be used as ideal CT scan-ning base line in the department of stereotactic and functional neurosurgery.