Wang L S, Zhang L L, Hu N, Liu S F, Li J Y, Wei P, Sun L X, Gong R Z
Department of Medical Imaging Center, Shandong Second Provincial General Hospital, Jinan 250022, China.
Department of Medical Imaging Center, Central Hospital Affiliated to Shandong First Medical University, Jinan 250013, China.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2024 Aug 7;59(8):803-811. doi: 10.3760/cma.j.cn115330-20231218-00304.
To summarize the HRCT and MRI appearances of stapical footplate fistula related to inner ear malformation (SFF-Re-IEM). The HRCT and MRI materials of 48 cases (53 ears) SFF-Re-IEM were retrospectively analyzed. Among them, 25 SFF-Re-IEM ears were confirmed by surgery. Their CT and MRI findings including associated IEM type, internal auditory canal (IAC) malformation, tympanic fluid, its density and signal features, and accompanied labyrinthitis were recorded. Among 48 cases (53 ears) with SFF-Re-IEM, 17 ears with incomplete partition type Ⅰ, accounting for 32.1%, 13 ears with common cavity for 24.5%, 13 ears with cochlear aplasia for 24.5%, 7 ears with cochlear dysplasia Ⅱ for 13.2%, and 3 ears with Mondini for 5.7%,were found respectively. 94.3% of them were associated with a defect or dysplasia in the found of the IAC. They were divided into 4 types according to the intact of the stapical footplate and accompanied CSF otorrhea: 22 ears were diagnosed as the stapical footplate leaking, of them, 2 ears might come from the stapical footplate bony defect, 6 ears were from the stapical footplate hernia. 1 ear belonged to the peristapical footplate leaking. 30 ears with the isolated the stapical footplate hernia were another found. The bony defect in 2 ears with the stapical footplate bony defect were not presented on CT and MRI.The focal bony defect of the affected stapical footplate of 36 ears with the stapical footplate hernia were demonstrated, which presented the hemispherical protruding into the tympana, the soft-tissue density on CT, and CSF-like signal on the MR heaved-T2WI images. Among 22 ears with the stapical footplate leaking, their imaging appearances varied from the different amount of the leaking CSF. Besides the focal bony defects of the affected stapical footplates, there were much more CSF-like density or signal in the ipsilateral tympanic cavity in 17 affected ears connecting with the vestibule through the defect area. In the CSF leaking ears with less CSF leaking in 5 ears, the CSF-like cysts like SFH were shown on the stapical footplate defect area, but their outer edges were irregular, and the CSF-like signal scattering in the tympanic cavity did not connect with the protruding cysts at the stapical area. The variable appearances of the SFF-Re-IEM ears based on the different subtypes are its characteristic HRCT and MRI appearances. This is helpful for the SFF-Re-IEM diagnosing to grasp its imaging features.
总结内耳畸形相关镫骨底板瘘（SFF-Re-IEM）的高分辨率CT（HRCT）及磁共振成像（MRI）表现。回顾性分析48例（53耳）SFF-Re-IEM患者的HRCT及MRI资料。其中25耳SFF-Re-IEM经手术证实。记录其CT及MRI表现，包括相关内耳畸形类型、内耳道（IAC）畸形、鼓室积液、其密度及信号特征，以及伴发的迷路炎。在48例（53耳）SFF-Re-IEM中，分别发现不完全分隔Ⅰ型17耳，占32.1%；共同腔13耳，占24.5%；耳蜗发育不全13耳，占24.5%；耳蜗发育异常Ⅱ型7耳，占13.2%；Mondini畸形3耳，占5.7%。94.3%伴有IAC底部缺损或发育异常。根据镫骨底板完整性及伴发脑脊液耳漏分为4型：诊断为镫骨底板漏22耳，其中2耳可能源于镫骨底板骨质缺损，6耳源于镫骨底板疝；1耳属于镫骨周围底板漏。另发现孤立性镫骨底板疝30耳。2例镫骨底板骨质缺损者CT及MRI未显示骨质缺损。36例镫骨底板疝患者患侧镫骨底板局灶性骨质缺损显示，呈半球形突入鼓室，CT呈软组织密度，MR重T2WI像呈脑脊液样信号。22例镫骨底板漏患者，其影像表现因漏出脑脊液量不同而异。除患侧镫骨底板局灶性骨质缺损外，17例患耳同侧鼓室通过缺损区与前庭相通处有更多脑脊液样密度或信号。5例脑脊液漏出较少的脑脊液漏耳，镫骨底板缺损区可见类似脑脊液囊肿样的结构，但边缘不规则，鼓室内脑脊液样信号散在分布，与镫骨区突出囊肿不相通。SFF-Re-IEM各亚型耳部表现各异，是其特征性HRCT及MRI表现。这有助于SFF-Re-IEM的诊断，以掌握其影像特征。
