中耳占位性病变的CT诊断

CT DIAGNOSIS OF MIDDLE EAR SPACE-OCCUPYING LESIONS

目的 :探讨中耳不同占位性病变的 CT诊断及鉴别诊断问题。方法 :对手术病理证实的 2 5例中耳良性及恶性占位性病变患者的 CT图像资料进行分析 ,分别总结其 CT诊断及鉴别诊断要点。结果 :1胆脂瘤 :肿物多为单发、中心多位于上鼓室或鼓窦入口区 ,常破坏鼓室盾板 ,骨破坏区边缘多清晰硬化 ,常见听小骨受压移位表现。 2炎性肉芽肿 :肿物呈多发结节状或斑片状 ,病灶常相连并紧贴鼓室或鼓窦壁附壁分布伴边缘清楚的骨破坏。 3中耳癌 :肿物及骨破坏区形态极不规则、边缘模糊不清 ,可累及中耳结构以外的骨结构 ;骨破坏区达乳突或岩骨边缘者 ,CT横断层面示乳突或岩骨边缘骨壁呈“多点中断”表现。结论 :听小骨移位及鼓室盾板骨破坏为诊断胆脂瘤最可靠和重要的依据 ;骨破坏区边缘模糊、乳突或岩骨边缘骨壁呈“多点中断”表现为中耳癌的特征性 CT征象。

Objective: To study CT diagnosis and differential diagnosis of various middle ear space occupying lesions Methods: High resolution CT findings of 25 patients with various middle ear space occupying lesions were analyzed,and the main points of CT diagnosis and differential diagnosis of various lesions were summarized Results: ①Cholesteatoma appeared mostly single soft mass whose center was on epitympanum or aditus and antrum, and accompanied usually with the scutum destruction The edge of the involved bone destructive region of all the patients were distinct and sclerosed Dislocation of the ossicular chain was showed in most of the patients ②Granuloma appeared multiple soft masses or soft patches which were usually joined mutually and kept close to the wall of tympanic cavity or antrum with edge distinct bone destruction ③Middle ear carcinoma manifested irregular soft mass and obvious bone destruction The lesion might invade the bone structures outside the middle ear The edge of the bone destructive region was indistinct and irregular in most of the patients Axial CT showed multi points interruption of the boundary wall of mastoid process or petrous bone in the patients whose lesion invaded to the edge of the mastoid process or petrous bone Conclusion:As characteristic CT features, scutum destruction and dislocation of the ossicular chain play an important roles in the diagnosis of cholesteatoma, as the indistinct edge of the bone destructive region and the multi points interruption of the boundary wall of mastoid process or petrous bone do in middle ear carcinoma diagnosis