前庭导水管解剖与CT对照研究

Vestibular aqueduct: anatomy and axial CT

目的:测量和了解在体前庭导水管(vestibularaqueduct,VA)CT解剖形态和正常大小。方法:(1)26块颞骨标本解剖和CT轴位扫描,观察和测量VA的解剖结构及其与周围重要结构(骨性半规管、内听道)的位置关系。(2)对36例临床诊断为单纯性中耳炎,无眩晕和明显听力障碍者进行颞骨轴位CT扫描图像进行VA的观察和测量,并与标本解剖图像和数据对照。结果:VA解剖形态呈倒“J”字形,外口形态多样,CT上VA内侧段难显示,外侧段短线状小管,内径1mm左右,VA外口前后径1～10mm,平均7.5mm。活体螺旋CT83%显示VA外口、67%显示外周段。结论:前庭导水管位置、形态固定。VA外口变异大,CT上难以准确测量其大小,因此不能单凭测量的数据判断VA发育情况。

Objective： To explore morphologic features of the vestibular aqueduct （VA）of normal adults. Methods： ①CT scan and anatomic dissection were performed on 26 temporal bone specimens from cadavers. Morphological study and measurement on VA were made and the distance between the adjacent structures （bony structures of semicircular canal and internal acoustic canal） and VA was assessed as well. ② Same evaluation and measurements were made on axial CT images of temporal bone in 36 patients with serous otitis media, who had no evident vertigo and hearing loss. Data from the specimens and patients were compared. Results： VA was a tiny bony canal with a reversed ＂J＂ shape on sectional images, variously shaped vestibular aqueduct external aperture （VAEA）. The internal portion of VA was rarely revealed on CT images, while the peripheral portion was about 1mm in diameter, representing a tiny canal on the thin-slice CT image. The VAEA was about 1-10 mm （averagely 7.5 mm） wide in anterior-posterior aspect. VAEA was demonstrated by CT scan in 83% patients, while the peripheral portion was revealed in 67% patients. Conclusions： VA is consistent in both the shape and the location. Because of the variation of VAEA, CT measurement could not be exact. It can not be used to evaluate the development of VA according to CT measurement.