Magnetic resonance imaging of the endolymphatic space in patients with benign paroxysmal positional vertigo: volume ratio and distribution rate of the endolymphatic space

Abstract

Background

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disease. It is characterised by sudden onset short lived vertigo triggered by sudden changes in head position relative to gravity.

Aims/Objectives

We aimed to perform a quantitative volumetric analysis of the inner ear endolymphatic space in patients with BPPV.

Material and Methods

This study included 67 patients with BPPV and 50 control subjects (CS). The endolymphatic space/total fluid space volume ratio (%) and the distribution rate of the inner ear components in the endolymphatic space (%) were measured using three-dimensional magnetic resonance imaging.

Results

Differences in the endolymphatic space/total fluid space volume ratio of the inner ear, cochlea, vestibule, and semi-circular canals (SCCs) between the CS and BPPV groups were not significant. The endolymphatic space distribution rate of the vestibule in the BPPV group was significantly lower than that in the CS group, and the endolymphatic space distribution rate of SCCs in the BPPV group was significantly higher than that in the CS group.

Conclusions and Significance

Extended endolymphatic space in patients with BPPV did not exist. The otoconia released from the damaged utricles were considered to move with the endolymphatic flow toward SCCs.

Chinese Abstract

背景：良性阵发性位置性眩晕（BPPV）是最常见的外周前庭疾病。它的特点是头部位置因重力导致突然变化而引发的突发短暂眩晕。

目的：对 BPPV 患者的内耳内淋巴空间进行定量体积分析。

材料和方法：研究包括 67 名 BPPV 患者和 50 名对照受试者 (CS)。使用三维磁共振成像测量内淋巴空间/总流体空间体积比（％）和内淋巴空间中内耳成分的分布率（％）。

结果：在CS和BPPV组之间, 内耳、耳蜗、前庭和半规管（SCCs）的内淋巴空间/总液体空间体积比的差异不显著。BPPV组前庭内淋巴空间分布率显著低于 CS 组, BPPV 组 SCC 的内淋巴空间分布率明显高于 CS 组。

结论和意义：BPPV 患者不存在扩大的内淋巴空间。从受损的椭圆囊中释放的耳石被认为随着内淋巴流一起移向 SCC。

Keywords:

• benign paroxysmal positional vertigo
• endolymphatic space
• endolymphatic flow
• magnetic resonance imaging
• volumetric measurement
• distribution rate

Acknowledgements

We would like to thank Professor Kimihiro Kichikawa, Dr. Toshiteru Miyasaka (Department of Radiology, Nara Medical University, Nara, Japan), Professor Shinji Naganawa, and Associate Professor Toshiaki Taoka (Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan). We would also like to thank Dr. Hitoshi Yoshimura and Dr. Masahiko Sakamoto, as well as other collaborators from the Department of Radiology, Kouseikai Takai Hospital, and Mrs. Yuka Katsube (Inui ENT Clinic) for data aggregation. We would like to thank Editage (www.editage.com) for English language editing.

Disclosure statement

The authors alone are responsible for the content and writing of this paper.