听骨链螺旋CT三维重建技术及初步临床应用

目的探讨听骨链螺旋CT三维重建技术的临床应用及局限性.方法采用螺旋CT薄层扫描(层厚1.0mm),Pitch1.5,小视野(FOV=9.0cm),密集重建(间隔0.5mm).观察22例,其中10例正常,12例耳部病变患者,所有病例均采用表面遮盖法(SSD)行听骨链三维重建成像.正常及异常耳的观察阈值分别为-200～-500HU和100～300HU.结果10例正常耳听骨链重建能直观显示锤、砧骨的大小、形态及相互关系,砧镫关节呈"L”形,镫骨前后脚及底板显示欠佳.12例患者中,3例胆脂瘤型及1例肉芽肿型中耳炎患者,3D图像显示有不同程度听小骨破坏,与手术所见基本相符.1例肉芽肿型、2例单纯型中耳炎及2例颞骨骨折患者听骨链3D图像均显示正常.2例中耳畸形显示听骨链发育异常.1例神经鞘瘤病显示听小骨被肿瘤组织破坏.结论螺旋CT三维重建技术能很好显示正常及异常听骨链的立体影像,有利于中耳炎、中耳畸形及其它耳部病变的诊断.

Spiral CT Three-dimensional Reconstruction of the Auditory Ossicular Chain and Its Preliminary Clinical Application

Objective To assess the clinical application and limitation of 3-D spiral CT of the auditory ossicular chain.Methods Spiral CT scan of the middle ear was performed with 1.0 mm slice thickness at pitch 1.5,9.0 cm filed of view,and 0.5 mm reconstruction interval in 10 nomal subjects and 12 patients with middle ear diseases.With the shaded surface display(SSD)3-D reconstruction of the auditory ossicular chain were done in all the patients,and the threshold values for normal and abnormal auditory ossicular chain were-200~500 HU and 100~300 HU,respectively.Results In 10 subjects with normal ossicular chain 3-D reconstruction images could directly display shapes,sizes and correlation of malleus and incus,and the incusstapedial joint was like "L"structure,but it was difficult to exhibit the footplate,and anterior and posterior crura of stapes.Of 12 abnormal cases,in 3 cholestesteatomatic cases with chronic otitis media,3-D reconstruction images demonstrated destructions of varying degrees that were in accord with those seen in operation.1 case with granulomas,2 cases with simple type otitis media and 2 cases of temporal bone fracture demonstrated normal auditory ossicular chain.In 2 cases with congenital anomaly,ossicle dysplasia was seen.Showed erosion of tumor to auditory ossicular chain in 1 case with schwannomatosis.Conclusion 3-D spiral;CT could clearly demonstrate three-dimensional images of the auditory ossicular chain,and it is useful to evaluate chronic otitis media,anatomic malformations and diseases of middle ear.