Congenital Inner Ear Malformations

KS Tse, KM Chu, LF Chiu, TW Fan, TK Tsang, TL Kwan

Hong Kong J Radiol 2011;14:118-25

Hearing impairment is defined as a person’s hearing threshold being above the normal range of -10 to 15 decibels. It has significant impact on a child’s language, cognitive, socioemotional and behavioural development. Therefore early recognition of hearing impairment is of utmost importance. Congenital inner ear malformation is an important cause of sensorineural hearing loss in children. It consists of labyrinthine aplasia, cochlear aplasia, common cavity deformity, cystic cochleovestibular anomaly (incomplete partition type I), cochlear hypoplasia, Modini deformity (incomplete partition type II). The imaging manifestations of these conditions on computed tomography examination are discussed in this article. Semicircular canal malformation and internal auditory canal deformities, namely: atresia of the internal auditory canal and X-linked progressive hearing loss, are also illustrated.

中文摘要

先天性內耳畸形

謝健燊、朱嘉敏、趙朗峰、范子和、曾子勤、關鼎樂

聽覺障礙是指聽力閾值超過正常範圍的-10至15分貝。聽覺障礙對於小童的語言能力、認知、社會情 緒及行為發展都有相當重要的影響，所以應盡早確定小童是否患有聽覺障礙。先天性內耳畸形是造 成小童感覺神經性聽力損失的一個重要原因，分為迷路發育不全、耳蝸發育不全、共同腔畸形、囊 性耳蝸前庭異常（未完全分隔一型）、耳蝸發育低下、和Modini內耳發育不全（未完全分隔二型） 不同種類。本文討論這些病變的CT表現。此外，亦討論半規管畸形及內聽道畸形，即內聽道閉鎖和 與X染色體有關的漸進式聽力損失。