三维容积重建对传导性耳聋听骨链的影像诊断

3D-CTVR in diagnosis of integrity and pathological changes of ossicular chain in conductive hearing loss

目的评估三维影像容积重建技术(three-dimensional volume rendered computer tomography,3D-CTVR)在耳硬化症与听骨链畸形/中断的传导性耳聋病例中对听骨完整性与病理状态的诊断与临床应用价值。方法回顾性分析经手术治疗的36例(耳)病。所有病例外耳道正常、鼓膜完整、传导性耳聋、A型鼓室曲线、盖莱试验阴性,病史为自幼渐进性听力下降。所有病例术前行CT检查并进行CTVR重建。根据影像,按照3分法评判原则,选择与手术相关的听骨链重要部位为评判内容,以术中所见为标准,以平片(轴位和冠状位)为对照,对3D-CTVR影像显示听骨重要部位的图像显示进行统计学分析。结果 3D-CTVR重建影像能够直观显示听骨链的完整性及病理状态;对镫骨上结构及镫骨上畸形的显示与手术实际相比P值大于0.05,较平片(P=0.00)能够更好的反应实际情况。结论 3D-CTVR能够很好的显示听骨链完整性及听骨的重要部位,对听骨精细结构的显示优于平片,二者结合更切合临床实际,这一技术为听骨链完整的耳硬化症和听骨链畸形/中断提供了更为可靠的客观鉴别诊断方法。

Objective To evaluate clinical values of three-dimensional volume rendered computer tomography （3D-CTVR） in diagnosing ossicular chain abnormalities in otosclerosis, and in ossicular chain absence/malformation （conductive heating loss with intact tympanic membrane）. Methods Thirty six patients participated in the study. All patients had conductive hearing loss, with intact tympanic membrane, normal external ear canal, type A tympanogram and negative Gelle＇ s test. All patients underwent pre-operative CT scan and the respective radiologic reports of ossicles were compared to surgical findings. Quantitative assessments of various segments of the ossicular chain were based on a 3-point scoring system. Using plain x ray as references, the sensitivity, specificity and accuracy of CTVR on different segments were evaluated in comparison to findings during the operation. Results 3D-CTVR images showed the integrity and pathological state of the ossicular chain well. CT imaging of stapes superstructure and malformations mostly agreed with surgical findings （P〉 0.05） and was superior to conventional plain x ray imaging （P=0.00）. Conclusion Together with conventional plain x ray, CTVR provides better view of fine ossicular chain structures in conductive heating loss with normal tympanic membranes. Furthermore, the use of CTVR may have profound value in the diagnosis of otosclerosis and ossicular chain absence or malformation.