前庭导水管的冠状面CT研究

Evaluation of Coronal CT Scanning in Observing Vestibular Aqueduct

目的 评价冠状面CT图像上正常前庭导水管 (VA)的特征 ,为不明原因感音神经性耳聋的诊断进一步提供依据。资料与方法 对 5 2名 10 4只正常耳作螺旋CT横断位及冠状位扫描 ,分别测量VA的宽度、长度 ,并在冠状面上测量VA长轴与水平线的夹角。然后对数据进行统计分析。结果 冠状面上VA峡部的显示率、可测率均为 10 0 % ;横断面上VA峡部的显示率为 10 0 % ,其可测率仅为 88.5 %。VA后部的显示率和可测率均为 6 1.5 %。冠状面VA峡部的宽度为 (0 .87± 0 .5 7)mm ,长度为 (3.0 7± 1.34)mm ;VA后部的宽度为 (1.2 3± 0 .5 1)mm ,长度为(4 .89± 1.6 1)mm。正常VA峡部的上限值为 4 .4mm× 1.5mm(长×宽 )。结论 冠状面上可清楚地观察VA的走行并对峡部进行测量 ,提出了冠状面上正常VA峡部的范围。冠状面结合横断面图像可提高VA扩大的诊断准确性 ,从而提高感音神经性耳聋患者的病因检出率。

Objective To study the imaging features of the normal vestibular aqueduct (VA) on coronal CT scans, to provide further evidence for the diagnosis of sensorineural hearing loss of unknown reason.Materials and Methods Both axial and coronal CT scanning were performed in 52 cases (104 normal ears). The width and length of VA, as well as the angle between the long axis of VA and horizontal level were measured. The data thus obtained were statistically analyzed. Results On coronal plane, both the displaying rate and measurable rate of VA isthmus were 100%. On axial plane, the displaying rate of VA isthmus was 100%, while its measurable rate was only 88.3%. Both the displaying rate and measurable rate of the posterior part of VA were 61.5%. On coronal plane, the width and length of VA isthmus were (0.87±0.57) mm and (3.07±1.34) mm, while the width and length of the posterior part of VA were 1.23±0.51mm and (4.89±1.61) mm, respectively. The normal upper limit of VA isthmus was 4.4mm by 1.5mm (length by width).Conclusion On coronal plane, the VA course can be well demonstrated and the VA isthmus can be easily measured. The normal values of VA isthmus on coronal plane are proposed. Combination of coronal with axial images will improve the diagnostic accuracy of VA dilatation and, thus, help find out the etiology of sensorineural hearing loss.