Imaging of the saccule for the diagnosis of endolymphatic hydrops in Meniere disease, using a three-dimensional T2-weighted steady state free precession sequence: accurate, fast, and without contrast material intravenous injection

Abstract

Background: Endolymphatic hydrops can be studied on magnetic resonance imaging (MRI) using images acquired 4 h after intravenous injection of Gd-chelate. Our aim was to compare high-resolution T2-weighted images of the saccule in normal subjects with histological sections from cadavers and to identify its changes in Meniere disease, compared to healthy volunteers.

Methods: Sixty-four healthy volunteers without any otologic disease and 64 patients who fulfilled all the criteria for unilateral Meniere disease underwent 3 T MRI using a T2-weighted steady state free precession (SSFP) sequence, without contrast material injection. Images of healthy volunteers were compared with histological sections of normal inner ears from premature foetuses and compared with volunteers.

Results: The normal saccule was easily visible on T2-weighted images in volunteers, with a normal maximal height of 1.6 mm (1.4 ± 0.1 mm, mean ± standard deviation) and a good correlation with reference histological sections, while in Meniere disease the saccule was dilated in 52/62 patients (84%), with a saccular height greater than 1.6 mm (1.69 ± 0.24 mm, p = 0.001), found in 45/52 patients (86%). An associated increased width (greater than 1.4 mm) was found in 23/52 patients (44%). A round shape or the non-visualisation of the saccule were also found in 2/52 (4%) and in 5/62 patients (8%), respectively.

Conclusions: A T2-weighted sequence is an easy method to diagnose Meniere disease. Saccular abnormalities were found in 84% of the cases: elongation (height > 1.6 mm) in 86%, increased saccular width in 44%, or a missing saccule in 8%.

Keywords: Endolymphatic hydrops; Magnetic resonance imaging (MRI); Meniere disease; Normal anatomy; Saccule.

Conflict of interest statement

The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

a Oblique lateral drawing of the membranous and bony labyrinth showing the saccule (S). b Schematic coronal drawing of the membranous and bony labyrinth. c Coronal histological section through the anterior part of the vestibule showing the saccule (S) below the utricular macula (arrow). d 3 T MRI. Coronal T2-weighted gradient-echo FIESTA-C image through the anterior part of the vestibule showing the saccule (S) and the hypointense signal of the utricular macula (arrow), as described in the equivalent histological section shown in c

Fig. 2

3T MRI. Coronal T2-weighted gradient-echo FIESTA-C image, through the anterior and external ampullas. Example of the measurements of the saccular height (arrows) and width (arrowheads)

Fig. 3

3T MRI. Four different healthy volunteers from the control group: a, b, c and d. Coronal T2-weighted gradient-echo FIESTA-C images through the anterior and external ampullas, showing a normal saccule (white arrows)

Fig. 4

3T MRI. Four different patients suffering from Meniere disease: a, b, c and d. Coronal T2-weighted gradient-echo FIESTA-C images through the anterior and external ampullas, showing four dilated saccules with an increased saccular height > 1.6 mm (white arrows)

Fig. 5

3T MRI. Coronal T2-weighted gradient-echo FIESTA-C images in two patients suffering from Meniere disease. 5 a) Dilated saccule with an increased saccular height (> 1.6 mm), associated with an increased saccular width (> 1.4 mm). 5 b) Round saccule with an isolated increased saccular width > 1.4 mm

Fig. 6

3T MRI. Coronal T2-weighted gradient-echo FIESTA-C in a patient suffering from Meniere disease. The saccule is not clearly visible (arrow), although there are not visible motion artefacts. The absence of visualisation of the saccule can be considered as pathological, as the saccule was always seen in the controls