CT仿真内镜在诊断骨性蜗神经管发育不良中的初步应用

Detection of Hypoplasia of Bony Cochlear Nerve Canal By Virtual Endoscopy: A Prilimitary Study

目的回顾性评价螺旋状结构消失作为CT仿真内镜诊断骨性蜗神经管发育不良的可行性。方法病例组包括14例(20耳)骨性蜗神经管发育不良者,对照组由无内耳及内听道疾患的50例(100耳)受试者组成。以临床及常规影像诊断结果作为骨性蜗神经管发育不良的诊断标准。仿真内镜观察骨性蜗神经管采用Flythrough技术并使用如下阈值:下限阈值850～1150,上限阈值3071。阳性结果指螺旋状结构或中央管消失;阴性结果指螺旋状结构或中央管存在。分别计算敏感性、特异性、准确性。结果病例组中17耳未显示螺旋状结构,3耳显示螺旋状结构,对照组中均显示螺旋状结构。观察者间有大量一致性(K=0.773)。以螺旋状结构消失作为征象诊断骨性蜗神经管发育不良的敏感性、特异性、准确性分别为85%、100%、98%。螺旋状结构消失在病例组及对照组之间有明显的统计学差异。结论螺旋状结构消失可以作为诊断骨性蜗神经管发育不良的有用征象。

Objective To retrospectively examine the feasibility of computed tomographic （CT） virtual endoscopy （VE） in the evaluation of hypoplasia of bony cochlear nerve canal （BCNC） base on absence of helix like shape. Methods Twenty ears in 14 consecutive patients diagnosed with BCNC hypoplasia and 100 ears in 50 gender- and age-matched in- dividuals without inner ear disease and internal auditory canal malformations were included in this work. The BCNCs of all subjects were reconstructed using 3D software program（ Fly Through ,3D）. The VE was performed applying low threshold of 850HU to 1150HU and high threshold of 3071HU. Hypoplasia BCNC was defined as absence of helix-like shape or central canal of the coehleaon CT VE. Normal result on CT VE was defined as presence of helix-like shape or central canal of the cochlea. Sensitivity, specificity and accuracy of CT VE were calculated. Results 17 of 20 ears of hypoplasia BCNC showed absence of helix like shape on CT VE. All of the ears of control subjects showed helix like shape and central canal of the cochlea on CT VE. Inter-observer agreement was substantial （ K = O. 773）. The BCNC hypoplasia was diagnosed based on absence of helix-like shape, the sensitivity, specificity and accuracy were 85% , 100% and 98% respectively. There were significant differences of absence of helix-like shape between the two groups （P 〈 0. 001 ）. Conclusion The absence of helix-like shape on CT VE images may be used as a potentially useful sign for diagnosis of BCNC hypoplasia.