3D-real IR MRI detects serendipity of inner ear in enlarged vestibular aqueduct syndrome

Abstract

Background: Although, the diagnostic criteria for enlarged vestibular aqueduct syndrome (EVAS) were determined by years. On the shoulders of predecessors, we still detected some new discoveries about EVAS by using 3D-real IR MRI.

Aims/objectives: To analyze the signal intensity of membranous and osseous labyrinths of vestibular aqueduct (VA) and endolymphatic sac (ES) in EVAS using three-dimensional real inversion recovery (3D-Real-IR) magnetic resonance imaging (MRI) after intratympanic injection of gadolinium.

Material and methods: The study is a prospective trial, diagnosed EVAS patients (n = 10) and none- patients (n = 10) were included. 3D-real-IR MRIs were performed to assess the endolymphatic hydrops (EH) and differentiated the endolymphatic and perilymphatic signal intensities of VA and ES.

Results: Compared to control group, EVAS group had VA osseous labyrinths middle diameter >1.5 mm different from membranous labyrinths. The cochlear EH was correlated with Mondini malformation and irrelation with the level of hearing loss (HL).

Conclusions and significance: Interspace of osseous labyrinths of VA and ES are much larger than their membranous labyrinths, which is not consistance with previous research. And cochlear Mondini malformation may cause endolymphatic fluid malabsorption, inducing cochlear EH. Osteal ampliative of VA and ES and cochlear EH, which are morphogenetic anomalies, may not the direct cause of HL in EVAS.

Chinese abstract

背景：前庭导水管扩大综合征（EVAS）的诊断标准是由年数来确定的。在前人研究成果的基础上, 我们用三维真反转恢复磁共振成像（IRMRI）取得了一些关于EVAS的新发现。

目的：经鼓室注射钆后, 应用三维真反转恢复（3D-REAL-IR）磁共振成像（MRI）技术, 分析EVAS的前庭导水管（VA）和内淋巴囊（ES）的膜和骨迷路的信号强度。

材料与方法：本研究为前瞻性试验, 对象是诊断为EVAS的患者（n=10）和非EVAS患者（n=10）。采用三维真反转恢复磁共振成像对内淋巴积水（EH）进行了评估, 并区分了VA和ES的内淋巴和外淋巴信号强度。

结果：与对照组相比, EVAS组的VA骨迷路中径大于1.5 mm, 与膜迷路不同。耳蜗EH与蒙蒂尼畸形相关, 与听力损失程度（HL）无关。

结论和意义：VA和ES骨迷路的间隙比膜迷路大得多, 这与以往的研究不一致。耳蜗蒙蒂尼畸形可引起内淋巴液吸收障碍, 诱发耳蜗EH。VA、ES和耳蜗EH的骨性放大是形态异常, 可能不是导致前庭导水管扩大综合征病人的听力损失的直接原因。

Keywords:

• Magnetic resonance imaging (MRI)
• intratympanic injection
• vestibular aqueduct (VA)
• endolymphatic sac (ES)
• endolymphatic hydrops (EH)

Disclosure statement

The authors declare no competing financial interests.

Additional information

Funding

This work was supported by the National Nature Science Foundation of China (Grant: 81670933 to Wuqing Wang; http://www.nsfc.gov.cn/).