双内听道的影像学特征

Imaging features of duplication of the internal auditory canal

目的 总结双内听道（duplication of internal auditory canal,DIAC）的多层螺旋CT和MRI影像学特点,提高对该病的认识.方法 结合文献回顾性分析4例（5耳）DIAC患者的影像学资料,4例均行多层螺旋CT检查,其中2例同时行MRI检查.结果 多层螺旋CT显示5耳内听道被骨性间隔分为双管状,上部骨管与面神经管相连,下部骨管与前庭和耳蜗相连,其中2耳骨性间隔不完整.5耳上下两管径之和均超过2 mm.3耳可显示蜗神经管狭窄.5耳均合并前庭扩大及外半规管发育不良,2例（2耳）同时合并小耳廓畸形,1耳合并小耳廓畸形、外耳道闭锁及听小骨发育不良.多平面重建（multiplanar reconstruction）、容积再现（volume rendering）图像可全面立体显示骨性间隔及双管结构.MRI显示1耳前庭和蜗神经发育不良、面神经完好,另1耳前庭、蜗神经和面神经均发育不良.结论 多层螺旋CT能清晰显示内听道被骨性间隔分为双管状及伴发畸形,可作为确诊DIAC的依据.MRI能表示其神经发育异常,为电子耳蜗植入对象的选择提供一定帮助.

WANG Lin-sheng（Department of CT, Aff Objective To explore multiple slices computed tomography （MSCT） and magnetic resonance imaging （ MRI） features of duplication of the internal auditory canal （ DIAC） in order to improve the accuracy of diagnosis. Methods Four cases（5 ears） were analyzed and the related documents were reviewed retrospectively. MSCT was performed on all cases, and two cases had MRI scanning at the same time. Results MSCT has shown that the internal auditory canal were divided into two canals by a bony septum in 5 ears. The superior canal ended in a very narrow connection to the facial canal, the inferior portion ended in connection to the cochlea and vestibule. The bony septums from the 2 ears were found no longer intact. The sum of diameter of the two canals was greater than 2 mm. In addition, S ears were found to have an enlarged vestibules and the hypoplasia lateral semicircular canals, and meanwhile, 2 ears of them were combined with ipsilateral microtia. Also 1 case of them was combined with microtia, outer acoustic atresia as well as abnormal middle ear. Multiplanar reconstruction and volume rendering images can entirely show the bony septum and two canals. In this study, the vestibular nerve, cochlear nerve and facial nerve were total hypoplastic in one ear, in the other ear, the vestibular and cochlear nerve were hypoplastic, and however, the facial nerve was intact. Conclusions MSCT can clearly depict duplaication of the internal auditory canals and concomitant anomalies. MRI can clearly show the neural components and their associated malformation.