POU3F4基因突变所致X连锁的非综合征型耳聋患者影像学表现

Imaging findings in patients with X-linked nonsyndromic deafness and a POU3f4 mutation

目的回顾性分析POU3F4基因突变所致X连锁的非综合征型耳聋患者HRCT和MRI表现及特征。方法收集4例POU3F4基因突变所致X连锁的非综合征型耳聋患者的HRCT和MRI资料,在二维图像上(多平面重组图像)上回顾性评价耳蜗、内听道、前庭、半规管、前庭导水管、内听道底神经管、镫骨和耳蜗神经,在三维图像上(CT仿真内镜图像)评价耳蜗神经孔。收集10例听力正常的患者影像资料作为对照组。结果患者内耳畸形是双侧对称性的。耳蜗畸形表现为耳蜗外形大致正常,蜗轴缺如,内听道与耳蜗内腔直接沟通;内听道外侧部扩张;CTVE直接显示螺旋形耳蜗内腔而非对照组所示的螺旋形蜗神经孔。面神经管迷路段和上前庭神经管扩张。Bill嵴肥大,部分气化。7耳发现镫骨底板增厚和镫骨前间隙消失,1耳镫骨呈柱状。结论蜗轴缺如、内听道外侧部扩张及镫骨底板增厚是本组POU3F4基因突变所致X连锁的非综合征型耳聋患者的典型影像学特征。此类患者术前检查可指导治疗方法的选择,应避免镫骨底板切除术而行人工电子耳蜗植入术,同时,影像学检查可预测电子耳蜗植入术中并发症,如脑脊液漏和电极进入内听道。

Objective The aim of this study was to analyze HRCT and MRI findings in patients with X-linked nonsyndromic deafness and a POU3f4 mutation. Methods HRCT and MRI data of four patients （males, 2~19 years old） with a POU3f4 mu-tation were collected and a retrospective review was performed. Cochlea, internal auditory canal （ IAC） , vestibule, semicircular canals, vestibular aqueduct, nerve canals in the IAC fundus, stapes and cochlear nerve were evaluated on 2D images （multi-plan-ner reformation, MPR） and cochlear foramen on 3D images （CT virtual endoscopy, CTVE）. Ten cases with normal hearing sub-jected to CT and MR exams were served as controls. Results Inner ear malformations were bilateral and symmetrical. Cochlear malformation was shown to consist of as a relatively normal outer coat shape, absence of a cochlear modilous, and a direct inter-communication between the IAC and cochlear inner cavity. The lateral portion of the IAC was dilated. A spiral cochlear inner cav-ity was observed with CTVE images versus a helical cochlear nerve foramen as seen in controls. The labyrinthine facial nerve canal and superior vestibular nerve canal were enlarged. The Bill＇ s bar was hypertrophic and partially pneumatized. A thickened stapes footplate was present and a fissura ante fenestram was absent in seven ears examined. A column shaped stapes was observed in one ear. Conclusion The absence of acochlear modilous with a dilatedlateral IAC and thickened stapes footplate were the remarka-ble features observed with imaging these in X-linkednon-syndromicdeafness patients with a POU3F4 mutation. Preoperative recog-nition of the image features in these patients is important because it precludes stapedectomy and indicates the risks in the surgery of cochlear implantation including CSF gusher and electrode insertion into IAC.