影像学在耳蜗发育不全Ⅳ型术前评估中的价值

The Value of Imaging Evaluation of Cochlear Hypoplasia Type Ⅳ before Operation

目的 总结耳蜗发育不全Ⅳ型的高分辨率CT(HRCT)或锥形束CT(CBCT)和MRI表现并进行相关径线的测量,为制定手术方案提供技术支持。方法 分析24例(42耳)耳蜗发育不全Ⅳ型的影像学资料,均行HRCT或CBCT检查,其中15例同时行MRI检查。观察内耳结构及镫骨形态等有无异常;在CT图像上测量耳蜗底转、中顶转、面神经管迷路段的长度、高度,耳蜗中顶转中心与底转中心之间的垂直距离等;在MRI图像上判断蜗神经发育情况。与31例(62耳)正常耳相应结构测量值对比分析。结果 24例患者42耳均表现为耳蜗体积小,底转接近正常,中转与顶转融合、位置前移,中转与顶转间的骨性分隔及蜗轴缺如。CH-Ⅳ组与对照组耳蜗相关测量值间差异均有统计学意义(均P<0.05)。而两组在除面神经管迷路段宽度差异无统计学意义外,其余面神经管相关测量值间差异均有统计学意义(均P<0.05)。结论 耳蜗发育不全Ⅳ型具有特征影像学征象,术前对耳蜗、面神经管、蜗神经等结构测量可为手术方案的制定提供客观依据。

Objective To analyze the imaging findings of cochlear hypoplasia type Ⅳ(CH Ⅳ) cochlea malformation using high resolution CT(HRCT) or cone beam computed tomography(CBCT) and MRI,and to measure the key anatomical structures, providing technical support for the development of surgical plans. Methods The imaging of 24 patients(42 ears) with CH Ⅳ were analyzed.All the patients underwent HRCT or CBCT,and 15 of them underwent MRI.The development of inner ear structure and the stapes were reviewed and analyzed.The length and height(width) of the cochlear base turn, middle apical turn, labyrinthine segment of facial nerve canal, and the vertical distance between the center of the cochlear parietal turn and the base turn were measured on CT.The development of cochlear nerve was analyzed on MRI.Compared the corresponding structure measurement values of 31 persons(62 ears) who showed no obvious ear abnormality and 24 patients(42 ears) with CH Ⅳ. Results The cochleae of the 24 patients had smaller dimensions close to normal basal turn, but middle and apical turns were severely hypoplastic and located anterior and medially rather than in their normal central position, and with defective modiolus and interscalar septa in middle and apical turns.There were significant statistical differences between the CH Ⅳ group and the control group in cochlear-related measurements(all P<0.05).Except for there were no significant statistical differences between two groups in the width of labyrinthine segment of facial nerve canal, other facial nerve canal related measurements had significant statistical differences between two groups(all P<0.05). Conclusion CH Ⅳ cochlea malformation has the characteristic imaging features.Preoperation accurate assessment and measurement of the important anatomical structures such as cochlea, facial nerve canal and facial nerve can provide objective information for the development of surgical plans.