Journal of Otology & RhinologyISSN: 2324-8785

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Research Article, J Otol Rhinol Vol: 4 Issue: 6

The Reliability of 3T MRI in Detecting Endolymphatic Hydrops in the Meniere’s Disease and Sudden Sensorineural Hearing Loss

Yang Liu*, Pengju Zhao, Dan Heng Zhao, Feng Yang, Qingjun Wang and Jianjun Sun
Department of Otolaryngology, PLA Navy General Hospital, Beijing, China
Corresponding author :Yang Liu
Department of Otolaryngology, PLA Navy General Hospital, Beijing 100048 China
E-mail: [email protected]
Received August 30, 2015 Accepted October 27, 2015 Published November 02, 2015
Citation: Liu Y, Zhao P, Zhao DH, Yang F, Wang Q, et al. (2015) The Reliability of 3T MRI in Detecting Endolymphatic Hydrops in the Meniere’s Disease and Sudden Sensorineural Hearing Loss. J Otol Rhinol 4:6. doi:10.4172/2324-8785.1000257

Abstract

Aim: The aim of this study was to assess the reliability of 3T MRI in detecting endolymphatic hydrops (EH) in the Meniere’s disease (MD) and sudden sensorineural hearing loss (SSHL).
Methods: Fifty patients with the unilateral clinical diagnosis of definite MD and twenty with unilateral sudden sensorineural hearing loss were evaluated with inner ear MRI. The MRI detection and imaging measurement was completed 24 hrs after intratympanic administration of gadolinium chelate. The sequence of MRI was three-dimensional fast spin-echo T1-weighted imaging (3D-FSET1WI).
Results: For the vestibule, the EH was visualized in 45 of 50 (90%) patients with MD and 4 of 20 (20%) patients with SSHL. For the cochlea, the EH was visualized in 46 of 50 (92%) patients with MD and 4 of 20 (20%) patients with SSHL.
Conclusion: For detecting EH in MD and SSHL, the inner ear MRI assessment after intratympanic injection of gadolinium is a useful and confident method for the diagnosis of EH in MD and SSHL. The present work also approved existence of EH in SSHL for the first time in the literature.

Keywords: Meniere’s disease; Sudden sensorineural hearing loss; Endolymphatic hydrops; MRI; Gadolinium

Keywords
Meniere’s disease; Sudden sensorineural hearing loss; Endolymphatic hydrops; MRI; Gadolinium
Introduction
EH is thought to be the cause of MD [1]. This pathophysiology describes an over accumulation of endolymph in the inner ear resulting in a swollen membranous labyrinth that occupies the perilymph. However, this diagnosis of hydrops is based on postmortem histologic examinations of the temporal bone. For the past decade, new research on EH has been developed. The discovery that uptake of gadolinium chelate in the perilymphatic compartment distinguishes the cochlear scalae and demonstrated the enlarged scala media occupying the area of scala vestibuli in an animal model of experimental endolymphatic hydrops made it possible to visualize endolymphatic hydrops in vivo [2]. Inner ear MRI of patients with Meniere’s disease after transtympanic injection of gadolinium chelate first demonstrated perilymphatic and endolymphatic spaces separately in humans in 2005 [3]. In 2009, Nakashima T reported the criteria of three-stage grading system to assess the hydrops quantitatively [4]. This paper reports the visualization results of 70 patients and analyzes percentage of endolymphatic hydrops in definite diagnosed MD (50 patients) and SSHL (20 patients). The aim was to assess the reliability of 3T MRI in detecting EH in the MD and SSHL.
Materials and Methods
Patient information
From February 2013 through September 2014, 70 cases from our department were selected for this study. This is a prospective research. All cases enrolled were approved by the ethics committee of our hospital. All the patients were underwent CT scans, and other diseases were excluded. The cases include 50 patients with unilateral MD and 20 patients with unilateral SSHL. Of the 50 patients with MD, 23 were male and 27 female, 21 were left ear and 29 were right, ranging in age from 25 through 73 (mean age: 49.74 ± 11.93). The diagnosis of MD was “definite diagnosis” according to the criteria established by the AAO-HNS (1995) [5]. The history ranged from three months to six years. Of the 20 patients with unilateral SSHL, 12 were male and 8 female, 11 were left ear and 9 were right, ranging in age from 11 through 78 (mean age: 43.95 ± 17.51). All 20 patients of SSHL were acute full frequency hearing loss, the history were from 1 to 30 days, the mean hearing level (0.5, 1, 2, 4 kHz) was 93.40±14.07 dB ranging from 55 through 110 dB, and the duration from the onset to MRI test was 3-30 days.
Intratympanic gadolinium injection
All patients were underwent intratympanic gadolinium injections (Gd, Magnevist, Bayer Schering Pharma AG, Guangzhou, China), and all operations were performed by one of the authors. The gadolinium contrast was diluted eight fold with saline. The diluted Gd was injected through the tympanic membrane using a 23-gauge needle. The volume injected was 0.3-0.5 ml. The injection was made at the post-inferior area of the tympanic membrane. After injection, the patient’s head was turned approximately 45 away from the sagittal line towards the opposite ear and kept for 1 hour.
MRI scans and evaluation
All patients underwent a 3T MRI (HDX; GE, US.) scan 24 h after intratympanic gadolinium injection. A bilateral 8-channel phasedarray surface coil was used. The three-dimensional fast spin-echo T1- weighted imaging (3D-FSE-T1WI) was applied to obtain contrastweighted images of endolymphatic gadolinium. The MRI parameters were as follows: repetition time (TR)/echo time (TE) is 520/31.1 ms, field of view (FOV) is 20 cm, matrix size is 512 × 256, slice thickness is 1.2 mm and signal averages is 2. The imaging was analyzed with image software (ImageJ 1.47t, Wayne Rasband, National Institutes of Health, USA) for evaluation of the endolymphatic space. The evaluation criteria adopted the three-stage grading system reported by Nakashima in 2009 [3]. For basal turn of the cochlea and vestibule, the EH (positive result) was conformed if the ratio of the area of the endolymphatic space to that of the sum of the endo- and perilymphatic space exceeded 33.3% (Figure 1). All judgments were made by one of the authors (radiologist). If there was a disagreement on the diagnosis, the final decision was made by one radiologist and two otologists, and if there was poor contrast enhancement, the cases were removed. SPSS software was used to complete the chi-square test (Figure 1).
Figure 1: Schematic picture of EH measurement. A: Basal turn of the cochlea. B: Vestibule. short arrow: superior semicircular canal; long arrow: lateral semicircular canal; dotted arrow: posterior semicircular canal. The dotted line indicates the sum of the endolymphatic and perilymphatic space. The solid line indicates the endolymphatic space. If the ratio of the area of the endolymphatic space to that of the sum of endo and perilymphatic space exceed 33.3%, the result was assessed to the “positive”.
Results
For the cases enrolled, the perilymphatic space could be detected as a high intensity area due to gadolinium enhancement by MRI 3D-FSE-T1WI sequence, while the endolymphatic space presented as a low or no signal intensity. The detected imaging was transferred to the imaging software to measure the ratio of endolymphatic space to the sum of endo-and perilymphatic space. Table 1 tabulated the results of two groups. For the vestibule, the EH was visualized in 45 of 50 (90%) patients with MD and 4 of 20 (20%) patients with SSHL. For the cochlea, the EH was visualized in 46 of 50 (92%) patients with MD and 4 of 20 (20%) patients with SSHL. Four patients of SSHL with positive result for the vestibular and/or cochlea are listed in Table 2.
Table 1: Positive result of EH in MD and SSHL.
Table 2: Patient profiles of SSHL with EH.
Figure 2A (male, 48 years old, left) shows the MRI contrast image of MD with intractable vertigo and deafness for 5 years. The patient underwent endolymphatic sac decompression and intratympanic administration of gentamycin, but there was no effect, and the patient accepted finally underwent labyrinthectomy with a good result. Figure 2B (male, 43 years old, right) shows the image of MD with intractable vertigo, fluctuating low-tone hearing loss, tinnitus, and ear fullness for 6 years. The patient underwent endolymphatic sac decompression but with an invalid result. We can see from Figure 2A and B that there was no contrast in the vestibule and semicircular canal, which means that the vestibular and semicircular canal spaces were occupied by endolymph.
Figure 2: A&B: Hydrops-positive cochlea. Empty arrows: vestibular and horizontal semicircular canal, the contrast could not enter the vestibular and semicircular canal with the result of low signal. Short arrow: perilymph, the high signal area of basal turn of the cochlea (contrast); long arrow: endolymph. the low signal area of basal turn of the cochlea (EH).
Figure 3A (Table 2, Patient No.1) was a patient of SSHL with tinnitus but no vertigo. Figure 4A shows the image tested by MRI 13 days after the onset. The imaging revealed significant EH in the left vestibule and the basal turn of the cochlea. There was no recovery of hearing for this patient. Figure 3B (Table 2, Patient No. 2) was a patient with sudden deafness with vertigo and tinnitus. The electronystagmography revealed lower vestibular function. Figure 3B shows the image tested by MRI 30 days after the onset. The imaging revealed significant EH in the left vestibule and the basal turn of the cochlea. After treatment, there was a partial recovery of low-tone hearing. Figure 3C (male, 49 years old, left ear) shows a patient of SSHL (hearing level 55dB) with tinnitus but no vertigo for 30 days. The Electronystagmography revealed normal vestibular function. Fig 3-C shows the image of this patient tested by MRI 30 days after the onset. The imaging revealed no EH in the left vestibule and cochlea.
Figure 3: A & B: Hydrops-positive vestibule and cochlea. Solid short arrow: high signal area in the vestibule (perilymph); Solid long arrow: low signal area of EH in the vestibule; dotted short arrow: high signal area in the basal turn of cochlea (perilymph); dotted long arrow: low signal area of EH in the basal turn of cochlea. C: Hydrops-negative vestibule and cochlea. Short solid and dotted arrow: high signal area in the vestibule and semicircular canal (perilymph); Long solid arrow: low signal area of endolymph in the vestibular.
Discussion
In 1995, the AAO-HNS established guidelines of MD [5]. Certain, definite, probable and possible MD were defined. The “certain” diagnosis is only after post mortem histological confirmation of EH. The clinical diagnosis is often based on history. For the past decade, researchers have invested a lot of time in this field, and the EH was detected by MRI [6,7]. In 2007, Nakashima T [8] reported the visualization of EH in patients with Meniere’s disease and in 2009 [4], reported the criteria of three-stage grading system to assessed the hydrops quantitatively. Also, Fang L [9] confirmed these criteria in healthy volunteers in 2011. Until now, this technique has been used in clinical work in the diagnosis of EH. But the question is how about the confidence? Can it be accepted by the otologists?
In our study, 45 (90%) patients with MD had positive result for EH in the vestibule and 46 (92%) in the cochlea. From the statistic result, we can see that the reliability of 3T MRI in detecting EH in MD was satisfactory. Fukuoka [10] reported the relationship between 3 T MRI after intratympanic injection of GBCA, the glycerol test, and ECoG in 20 patients with Meniere’s disease (MD). A positive result was observed in 11 patients (55%) in the glycerol test, in 12 patients (60%) by ECoG and in 19 patients (95%) patients for 3T MRI test. EH is theoretically a constant histopathological finding and should be visualized on MRI. Pyykkö I and Zou J[6] reported that the EH had been shown in almost all patients with definite and probable certainty in inner ear imaging in their study of more than 100 ears. Baráth K [11] reported that the EH had been detected in 100% of ears with the clinical diagnosis of definite MD. In our study, there was no visualization of hydrops in one patient in the vestibule and 4 patients in the cochlea, and we believe that one reason is the poorer permeability of contrast from the round window into the inner ear as reported by Horii A [12] and Yoshioka M [13], another is the disappearance of hydrops in the intermittent period of the attack. Merchant SN [14] reported that the symptoms of Meniere’s syndrome existed during life but no hydrops was observed on histology. Lastly, we think that the technical factors should be considered, including the intratympanic gadolinium injection, the MRI sequence and the assessment of imaging. In addition, EH may be present either locally or throughout the inner ear. Merchant SN [14] reported this phenomenon in 2005.
Merchant SN [15] reported that there were EH in both ears in the temporal bone histopathology examination of 17 ear with idiopathic SSHL. One patient experienced sudden, severe hearing loss but without vestibular symptoms. Another patient developed typical MD in his left ear characterized by episodic vertigo and sensorineural hearing loss. Katayama N [16] reported that none of the four patients with sudden deafness had endolymphatic drops detected by MRI with intratympanic gadolinium. Horii A [12] reported that 2 of the 8 patients with sudden deafness had EH detected by MRI taken several months after the onset. Horii could not confirm whether the hydrops existed from the early onset of sudden deafness or developed after the partial recovery. Horii concluded that these hydrops were not related to the pathogenesis of sudden deafness and were secondary hydrops. In our study of 20 patients with SSHL, 4 patients (Table 2) had EH detected by MRI at the early onset, patient No. 1 and No. 4 had no recovery of hearing at all frequencies, and patients No. 2 and No. 3 had recovered 30 and 25 dB at the low tone hearing (average of 0.125, 0.5, and 1 kHz). Patient No. 2 and No. 3 had vertigo. Theoretically, the EH was classified as secondary hydrops caused by other known disease, delayed hydrops after serious sudden deafness and idiopathic hydrops produced at the onset of the disease. In our study, regarding the two patients with EH (accompanied by vertigo) and low tone hearing recovery, is it idiopathic hydrops? If this conclusion is true, maybe it was MD with serious hearing loss of all frequencies. Although this finding needs further study, the fact that the EH was visualized on MRI imaging at the onset of sudden deafness was indisputable.
Conclusion
In detecting EH, the inner ear MRI assessment after intratympanic injection of gadolinium is a useful and confident method for the diagnosis of EH in MD. The present work also approved existence of EH in SSHL for the first time in the literature.
Acknowledgments
We thank Prof. Jie Chen for generously providing his assistance in the statistical portion of our study. Also we would like to thank LetPub for its linguistic assistance during the preparation of this manuscript.
Financial Support The study was supported by research grants of clinical application from the Beijing science and Technology Committee (Z141107002514104).

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