Temporal changes in endolymphatic hydrops on MRI with or without intervention: A systematic review.

OBJECTIVE: The pathophysiology of Meniere's Disease (MD) involves endolymphatic hydrops (ELH) of the inner ear. Magnetic Resonance Imaging (MRI) has been shown to detect ELH, but changes in ELH have been poorly described using this modality. Our objective was to review MRI-measured changes in ELH over time and after medical and/or surgical intervention in patients with MD. We secondarily aim to associate changes in ELH with changes in MD symptomatology. DATABASES REVIEWED: Medline, Web of Science, and Embase databases. METHODS: A systematic review of articles was performed to identify studies utilizing MRI to measure ELH changes over time, and after medical or surgical treatment. Articles on non-human subjects and without direct measurement of ELH were excluded. RESULTS: Of 532 studies identified, 12 were included, involving 170 patients (mean age 56.3 years). Ten studies were prospective; two were retrospective. Five studies strictly utilized medical means of intervention, four utilized surgical treatments, one utilized both, and two observed temporal changes without treatment. Across all interventions, 72.1 % of patients exhibited the same or worsening ELH on imaging. In studies reporting vertigo outcomes, 95.9 % of patients exhibited improvement after the treatment period. CONCLUSION: Medical and surgical interventions often yield symptomatic relief of vertigo in MD patients despite stable or increasing ELH volume. MRI may have greater clinical utility in diagnosing ELH as opposed to assessing treatment response.

Low-salt diet increases mRNA expression of aldosterone-regulated transporters in the intermediate portion of the endolymphatic sac.

The endolymphatic sac is a small sac-shaped organ at the end of the membranous labyrinth of the inner ear. The endolymphatic sac absorbs the endolymph, in which the ion balance is crucial for inner ear homeostasis. Of the three sections of the endolymphatic sac, the intermediate portion is the center of endolymph absorption, particularly sodium transport, and is thought to be regulated by aldosterone. Disorders of the endolymphatic sac may cause an excess of endolymph (endolymphatic hydrops), a histological observation in Meniere's disease. A low-salt diet is an effective treatment for Meniere's disease, and is based on the assumption that the absorption of endolymph in the endolymphatic sac abates endolymphatic hydrops through a physiological increase in aldosterone level. However, the molecular basis of endolymph absorption in each portion of the endolymphatic sac is largely unknown because of difficulties in gene expression analysis, resulting from its small size and intricate structure. The present study combined reverse transcription-quantitative polymerase chain reaction and laser capture microdissection techniques to analyze the difference of gene expression of the aldosterone-controlled epithelial Na+ channel, thiazide-sensitive Na+-Cl- cotransporter, and Na+, K+-ATPase genes in the three individual portions of the endolymphatic sac in a rat model. A low-salt diet increased the expression of aldosterone-controlled ion transporters, particularly in the intermediate portion of the endolymphatic sac. Our findings will contribute to the understanding of the physiological function of the endolymphatic sac and the pathophysiology of Meniere's disease.

Space-Occupying Lesions of the Inner Ear Are Easily Misdiagnosed as Endolymphatic Hydrops in a Perilymph-Enhanced Sequence Without the Assistance of a Heavily T2-Weighted Sequence.

OBJECTIVE: The aim of the study was to explore the value of T2-sampling perfection with application-optimized contrasts by using different flip angle evolutions (T2-SPACE) in identifying space-occupying lesions of the inner ear. METHODS: We collected the T2-SPACE and 3-dimensional inversion-recovery sequence with real reconstruction (3D-real IR) images of 220 patients with inner ear symptoms, including 15 patients with inner ear space-occupying lesions. With T2-SPACE images hidden, a senior and junior radiologist made a diagnosis for all patients using only the 3D-real IR images. After 4 weeks the images were shuffled, and T2-SPACE images were made available to the 2 radiologists in addition to 3D-real IR to reconsider the diagnosis for all patients. RESULTS: With the SPACE images hidden, the correct diagnosis rate of the space-occupying lesions was 8/15 (53.3%) for the senior radiologist, whereas it was only 2/15 (13.3%) for the junior radiologist. Without the SPACE images hidden, the correct diagnosis rate of the space-occupying lesions was 15/15 (100.0%) for the senior radiologist, whereas it was 13/15 (86.7%) for the junior radiologist. Of the 15 patients, 7 had only vestibular space-occupying lesions, 2 had only cochlear space-occupying lesions, and 6 had both. No semicircular canal space-occupying lesion was observed. CONCLUSIONS: T2-SPACE can help identify space-occupying lesions of the inner ear that tend to be misdiagnosed as endolymphatic hydrops on 3D-real IR. The senior radiologist had a higher rate for the identification of space-occupying lesions than the junior radiologist when using only 3D-real IR, although the senior radiologist detection rate was still only 53.3%. With the addition of T2-SPACE, both the junior and senior radiologist achieved a high detection rate, which increased to 86.7% and 100%, respectively.

Inner ear pathologies impair sodium-regulated ion transport in Meniere's disease.

Meniere's disease (MD), a syndromal inner ear disease, is commonly associated with a pathological accumulation of endolymphatic fluid in the inner ear, termed "idiopathic" endolymphatic hydrops (iEH). Although numerous precipitating/exacerbating factors have been proposed for MD, its etiology remains elusive. Here, using immunohistochemistry and in situ protein-protein interaction detection assays, we demonstrate mineralocorticoid-controlled sodium transport mechanisms in the epithelium of the extraosseous portion of the endolymphatic sac (eES) in the murine and human inner ears. Histological analysis of the eES in an extensive series of human temporal bones consistently revealed pathological changes in the eES in cases with iEH and a clinical history of MD, but no such changes were found in cases with "secondary" EH due to other otological diseases or in healthy controls. Notably, two etiologically different pathologies-degeneration and developmental hypoplasia-that selectively affect the eES in MD were distinguished. Clinical records from MD cases with degenerative and hypoplastic eES pathology revealed distinct intergroup differences in clinical disease presentation. Overall, we have identified for the first time two inner ear pathologies that are consistently present in MD and can be directly linked to the pathogenesis of EH, and which potentially affect the phenotypical presentation of MD.

3D-real IR MRI of Meniere's disease with partial endolymphatic hydrops.

OBJECTIVES: A three-dimensional inversion-recovery sequence with real reconstruction (3D-real IR) sequence 4 h after intravenous gadolinium injection (IV) has been used to visualize the endolymphatic hydrops (ELH) in Meniere's disease (MD). This study was designed to explore the pathology of MD with partial ELH. METHODS: We collected 338 patients with definite MD, all of whom underwent the IV method. Patients who were found to have partial ELH (vestibular or cochlear) were enrolled. The hearing thresholds of the enrolled patients were analyzed, the regions of interest of the cochlear perilymph and the cerebellum white matter were determined, and the signal intensity ratio in the former to the latter (CC ratio) for both sides in the patients was subsequently evaluated. RESULTS: Of the 338 collected patients with definite MD, 19 patients (5.6%) had unilateral vestibular ELH (N = 18) or cochlear ELH (N = 1), and 4 patients (1.2%) with bilateral ELH had contralateral cochlear ELH. The CC ratio of the affected side (1.44 ±â€¯0.46) was higher than that of the unaffected side (1.15 ±â€¯0.33, P < 0.05) in the 19 patients with unilateral ELH. Conversely, there was no difference between the ratio of the contralateral side (1.18 ±â€¯0.16) and the unaffected side (P > 0.05) in the 4 patients with bilateral ELH. CONCLUSIONS: Partial vestibular ELH was more common than partial cochlear ELH in MD. Moreover, vestibular ELH, rather than cochlear ELH, may correlate with the elevated contrast effect in the affected side, which may better reflect the pathologic mechanism of MD.

MRI of endolymphatic hydrops in patients with vestibular schwannomas: a case-controlled study using non-enhanced T2-weighted images at 3 Teslas.

OBJECTIVE: Vestibular schwannomas (VS) may present with similar symptoms endolymphatic hydrops. Association between hydrops and internal auditory canal VS has been described by Naganawa et al. (Neuroradiology 53:1009-1015, 2011), but has never been confirmed since. The aim of this work was to study the prevalence of a saccular dilation on a T2-weighted sequence at 3 T MRI in VS compared to a control group. MATERIALS AND METHODS: All patients presenting with typical VS between May 2009 and July 2018 were included (n = 183) and compared to a control group (n = 53). All underwent a high-resolution T2-weighted 3D sequence (FIESTA-C). The height and width of the saccule were measured on a coronal plane by two radiologists. RESULTS: The saccule was dilated on the side of the schwannoma in 28% of the cases (p = 2.81 × 10- 5), with 15.7% of bilateral dilation. Saccular dilation was correlated to sensorineural hearing loss (OR 3.26, p = 0.02). There was also a significant correlation between saccular hydrops on the normal contralateral side of patients with VS and vertigo (p = 0.049), and between saccular hydrops on the side of the tumour and tinnitus (p = 0.006). CONCLUSION: A third (29%) of VS are associated with a saccular dilation on the side of the tumour, which is an MR sign of endolymphatic hydrops (bilateral in 15.7% of the cases) and it appears related to sensorineural hearing loss and tinnitus, as well as vertigo if a contralateral dilation is present. This opens new therapeutic potentialities with the use of anti-vertiginous drugs, which could have a beneficial effect on the clinical symptoms.

MRI of endolymphatic hydrops in patients with Meniere's disease: a case-controlled study with a simplified classification based on saccular morphology.

OBJECTIVES: Endolymphatic hydrops (EH) can be studied in patients by MRI. With the semi-quantitative grading system, previous imaging studies showed discrepancies in the occurrence and grading of EH in patients with Meniere's disease (MD). Here, we compared the inversion of the saccule to utricle area ratio (SURI) with the semi-quantitative method of grading conventionally used to diagnose MD. METHODS: Imaging was carried out on a 3-T MRI scanner. We performed 3D-FLAIR sequences 4 h after a single intravenous dose of contrast agent. Two radiologists independently studied the morphology of the inner ear structures in the healthy subjects and MD patients. Each subject was then graded on the basis of the EH semi-quantitative analysis and on saccular morphology using axial and sagittal reference slices in the vestibule plane. RESULTS: Thirty healthy subjects and 30 MD patients had MRI scans. Using the semi-quantitative method, we found no significant difference in the number of subjects with EH between the two groups. SURI was found in 15 out of 30 MD patients and in none of the 30 healthy subjects. In three MD patients the saccule was not visible. CONCLUSION: SURI is currently the most specific criterion for imaging diagnosis of MD. KEY POINTS: • Half of MD patients presented with inversion of the saccule to utricle ratio. • Saccular analysis is crucial when assessing patients with Meniere's disease. • In some patients, the saccule is not visible, suggestive of intra-labyrinthine fistulae.

Clinical features of delayed endolymphatic hydrops and intralabyrinthine schwannoma : An imaging-confirmed comparative case series. English version.

BACKGROUND: The aim of this study was to compare the clinical history and audiovestibular function test results of patients suffering from intralabyrinthine schwannoma or delayed endolymphatic hydrops (DEH). PATIENTS AND METHODS: Five patients diagnosed with intralabyrinthine schwannoma by magnetic resonance imaging (MRI) and five patients diagnosed with DEH by locally enhanced inner ear MRI (LEIM) were retrospectively studied. RESULTS: All patients with intralabyrinthine schwannoma or DEH initially presented with hearing loss. Vertigo occurred in two patients with intralabyrinthine schwannoma and in all patients with DEH. While audiometry achieved poorer results for patients with intralabyrinthine schwannomas, vestibular function tests revealed normal results in about half of the patients in both groups. CONCLUSION: Patients with intralabyrinthine schwannomas may present with clinical symptoms similar to patients suffering from other inner ear disorders such as delayed endolymphatic hydrops and they may obtain similar findings in audiovestibular function tests. High-resolution magnetic resonance imaging with locally applied contrast agent may provide evidence of both underlying pathologies.

Effect of Endolymphatic Hydrops on Sound Transmission in Live Guinea Pigs Measured with a Laser Doppler Vibrometer.

Objective. This study aimed at describing the mechanism of hearing loss in low frequency and the different dynamic behavior of the umbo, the stapes head, and the round window membrane (RWM) between normal guinea pigs and those with endolymphatic hydrops (EH), using a laser Doppler vibrometer (LDV). Methods. Cochlear sections were stained with hematoxylin and eosin (HE) to evaluate the hydropic ratio (HR). Auditory brainstem responses (ABR) and whole-mount immunostaining were measured. Displacement of the umbo, stapes head, and RWM in response to ear-canal sound was evaluated using a LDV. Results. Mean HR values in EH model of all the turns are larger than the control group. The ABR threshold of the EH group was significantly higher than that of the control. Strong positive correlation was found between HR at apical turn and ABR threshold elevation at 1000 Hz and at subapical turn and ABR threshold elevation at 2000 Hz. FITC-phalloidin immunostaining of the cochlear basilar membrane in the apical, subapical, and suprabasal turns showed missing and derangement stereocilia of third-row outer hair cells. The umbo, stapes head, and RWM displacement in ears with EH was generally lower than that of normal ears. The EH-induced differences in stapes head and RWM motion were significant at 0.5 kHz. Conclusion. The LDV results suggested that the higher inner ear impedance in EH affected the dynamic behavior of the two opening windows of the cochlea and then reduced the vibration of the ossicular chain by increasing the afterload, resulting in acoustic dysfunction. The vibration reduction mainly occurred at low frequencies, which has related with the morphology changes of the apical and subapical turns in EH model.

Histopathologic ear findings of syphilis: a temporal bone study.

To the best of our knowledge, histopathologic studies of syphilitic ears have generally focused on hydropic changes; so far, no such studies have investigated peripheral vestibular otopathology using differential interference contrast microscopy, in patients with syphilis. For this study, we examined 13 human temporal bone samples from 8 patients with a history of syphilis. Using conventional light microscopy, we performed qualitative histopathologic assessment. In addition, using differential interference contrast microscopy, we performed type I and type II vestibular hair cell counts on each vestibular sense organ with minimal autolysis; in which the neuroepithelium was oriented perpendicular to the plane of section. We then compared vestibular hair cell densities (cells per 0.01 mm² surface area) in the syphilis group vs. the control group. In the syphilis group, we observed precipitate in the endolymphatic or perilymphatic spaces in 1 (7.7 %) of the samples and endolymphatic hydrops in eight (61.5 %) of the samples. Hydrops involved the cochlea (four samples) and/or saccule (four samples). In addition, the syphilis group experienced a significant loss of type II vestibular hair cells in the maculae of the utricle and saccule, and in the cristae of the lateral and posterior semicircular canals, as compared with the control group (P < 0.05).

Association between the Putative Meningeal Lymphatics at the Posterior Wall of the Sigmoid Sinus and Delayed Contrast-agent Elimination from the Cerebrospinal Fluid.

PURPOSE: To investigate the characteristics of the putative meningeal lymphatics located at the posterior wall of the sigmoid sinus (PML-PSS) in human subjects imaged before and after intravenous administration (IV) of a gadolinium-based contrast agent (GBCA). The appearance of the PML-PSS and the enhancement of the perivascular space of the basal ganglia (PVS-BG) were analyzed for an association with gender, age, and clearance of the GBCA from the cerebrospinal fluid (CSF). METHODS: Forty-two patients with suspected endolymphatic hydrops were included. Heavily T2-weighted 3D-fluid attenuated inversion recovery (hT2w-3D-FLAIR) and 3D-real inversion recovery (IR) images were obtained at pre-administration, immediately post-administration, and at 4 and 24 hours after IV-GBCA. The appearance of the PML-PSS and the presence of enhancement in the PVS-BG were analyzed for a relationship with age, gender, contrast enhancement of the CSF at 4 hours after IV-GBCA, and the washout ratio of the GBCA in the CSF from 4 to 24 hours after IV-GBCA. RESULTS: The PML-PSS and PVS-BG were seen in 23 of 42 and 21 of 42 cases, respectively, at 4 hours after IV-GBCA. In all PML-PSS positive cases, hT2w-3D-FLAIR signal enhancement was highest at 4 hours after IV-GBCA. A multivariate analysis between gender, age, CSF signal elevation at 4 hours, and washout ratio indicated that only the washout ratio was independently associated with the enhancement of the PML-PSS or PVS-BG. The odds ratios (95% CIs; P value) were 4.09 × 10-5 (2.39 × 10-8 - 0.07; 0.0078) for the PML-PSS and 1.7 × 10-4 (1.66 × 10-7 - 0.174; 0.014) for the PVS-BG. CONCLUSION: The PML-PSS had the highest signal enhancement at 4 hours after IV-GBCA. When the PML-PSS was seen, there was also often enhancement of the PVS-BG at 4 hours after IV-GBCA. Both observed enhancements were associated with delayed GBCA excretion from the CSF.

A mouse model of autoimmune inner ear disease without endolymphatic hydrops.

Autoimmune inner ear disease (AIED) is an organ-specific disease characterized by irreversible, prolonged, and progressive hearing and equilibrium dysfunctions. The primary symptoms of AIED include asymmetric sensorineural hearing loss accompanied by vertigo, aural fullness, and tinnitus. AIED is divided into primary and secondary types. Research has been conducted using animal models of rheumatoid arthritis (RA), a cause of secondary AIED. However, current models are insufficient to accurately analyze vestibular function, and the mechanism underlying the onset of AIED has not yet been fully elucidated. Elucidation of the mechanism of AIED onset is urgently needed to develop effective treatments. In the present study, we analyzed the pathogenesis of vertigo in autoimmune diseases using a mouse model of type II collagen-induced RA. Auditory brain stem response analysis demonstrated that the RA mouse models exhibited hearing loss, which is the primary symptom of AIED. In addition, our vestibulo-oculomotor reflex analysis, which is an excellent vestibular function test, accurately captured vertigo symptoms in the RA mouse models. Moreover, our results revealed that the cause of hearing loss and vestibular dysfunction was not endolymphatic hydrops, but rather structural destruction of the organ of Corti and the lateral semicircular canal ampulla due to an autoimmune reaction against type II collagen. Overall, we were able to establish a mouse model of AIED without endolymphatic hydrops. Our findings will help elucidate the mechanisms of hearing loss and vertigo associated with AIED and facilitate the development of new therapeutic methods.

Association Between Vestibular Aqueduct Morphology and Meniere's Disease.

OBJECTIVE: To investigate the relationship between vestibular aqueduct (VA) morphology and Meniere's disease (MD) using ultrahigh-resolution computed tomography (U-HRCT). METHODS: Retrospective data were collected from 34 patients (40 ears) diagnosed with MD in our hospital who underwent temporal bone U-HRCT with isotropic 0.05-mm resolution, magnetic resonance with gadolinium-enhanced, and pure-tone audiometry; 34 age- and sex-matched controls (68 ears) who underwent U-HRCT were also included. VA patency was qualitatively classified as locally not shown (grade 1), locally faintly shown (grade 2), or clearly shown throughout (grade 3). The width of the outer orifice and VA length and angle were quantitatively measured. Differences in VA morphology between the MD and control groups were analyzed. The correlations between VA morphology and the degrees of hearing loss and endolymphatic hydrops (EH) were also analyzed. RESULTS: VA was classified as grades 1-3 in 11, 17, and 12 ears in the MD group and 5, 26, and 37 ears in the control group, respectively. The patency differed significantly between the groups (p < 0.01). The width of the outer orifice and length of VA were significantly smaller in the MD group than those in the control group (p < 0.05). Both VA patency and length were correlated with the degree of EH in the cochlea and the vestibule (p < 0.05). No difference was found between VA morphology and the degree of hearing loss (p > 0.05). CONCLUSION: The morphological characteristics of VA were found to be associated with the occurrence of MD and the degree of EH. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3349-3354, 2024.

Morphological and functional changes in a new animal model of Ménière's disease.

The purpose of this study was to clarify the underlying mechanism of vertiginous attacks in Ménière's disease (MD) while obtaining insight into water homeostasis in the inner ear using a new animal model. We conducted both histopathological and functional assessment of the vestibular system in the guinea-pig. In the first experiment, all animals were maintained 1 or 4 weeks after electrocauterization of the endolymphatic sac of the left ear and were given either saline or desmopressin (vasopressin type 2 receptor agonist). The temporal bones from both ears were harvested and the extent of endolymphatic hydrops was quantitatively assessed. In the second experiment, either 1 or 4 weeks after surgery, animals were assessed for balance disorders and nystagmus after the administration of saline or desmopressin. In the first experiment, the proportion of endolymphatic space in the cochlea and the saccule was significantly greater in ears that survived for 4 weeks after surgery and were given desmopressin compared with other groups. In the second experiment, all animals that underwent surgery and were given desmopressin showed spontaneous nystagmus and balance disorder, whereas all animals that had surgery but without desmopressin administration were asymptomatic. Our animal model induced severe endolymphatic hydrops in the cochlea and the saccule, and showed episodes of balance disorder along with spontaneous nystagmus. These findings suggest that administration of desmopressin can exacerbate endolymphatic hydrops because of acute V2 (vasopressin type 2 receptor)-mediated effects, and, when combined with endolymphathic sac dysfunction, can cause temporary vestibular abnormalities that are similar to the vertiginous attacks in patients with MD.

Evaluation of the internal structure of normal and pathological Guinea pig cochleae using optical coherence tomography.

Optical coherence tomography (OCT) makes it possible to visualize the internal structures of several organs, such as the eye, in vivo. Although visualization of the internal structures of the inner ear has been used to try and identify certain pathological conditions, attempts have failed mainly due to the thick bony capsule surrounding this end organ. After decalcifying the bony wall of the cochlea with ethylenediamine tetraacetic acid, we could clearly visualize its internal structures by using OCT. We identified endolymphatic hydrops, strial atrophy and damage to the organ of Corti, evident as a distention of Reissner's membrane, thinning of the lateral wall and flattening of the organ of Corti, respectively. When specimens embedded in paraffin, sliced and stained with hematoxylin and eosin (HE) were examined under a light microscope, the OCT images of normal and pathological cochleae were virtually identical with those of the HE specimens, except that the HE specimens exhibited several artifacts unrecognized in OCT images, which were considered to be induced during the preparation process. Since OCT enables one to obtain arbitrary plane images by manipulating the slice axis of the specimens and avoids any misinterpretation due to artifacts induced during histological preparation, our technique would be useful for examining cochlear pathologies without or prior to histological evaluations.

Geometrical and volume changes of the membranous vestibular labyrinth in guinea pigs with endolymphatic hydrops.

OBJECTIVE: To evaluate geometrical and volume changes of membranous vestibular labyrinths in guinea pigs after endolymphatic hydrops (EH). METHODS: The membranous labyrinths of normal guinea pigs and of those with EH for 4 and 8 weeks were reconstructed after being scanned using micro-computed tomography subseqent to being stained in osmium tetroxide (OsO4). The diameters and volumes of the semicircular ducts, ampullae, utricles and saccules were measured based on the three-dimensional models. RESULTS: The diameters of the ampullae and utricles of EH guinea pigs were greater than those of the normal guinea pigs, while there were no significant differences in the diameters of the semicircular ducts among all groups. The volumes of ampullae, utricles and saccules of the EH groups were greater than those of the control group, but there were no changes in volumes of semicircular ducts after EH. CONCLUSION: The dilations of the membranous vestibular labyrinth in guinea pigs with EH mainly occur at the ampullae, utricles and saccules.

[Endolymphatic hydrops detected with inner ear gd contrast-enhanced MRI; comparison between administration routes or with ECochG or glycerol test].

OBJECTIVE: Gadolinium (Gd) contrast-enhanced MRI has recently been introduced to clinical practice to detect endolymphatic hydrops. However, since the image depends on the hardware, pulse sequence or the way of Gd administration, the protocol and the evaluating criteria for hydrops on MRI have not yet been standardized. In this study, we assessed the usefulness of the hydrops detection by MRI following the intratympanic or intravenous Gd administration methods, and compared these findings with the electrocochleography and glycerol test. METHODS: MRI was taken in 27 patients with Meniere's disease or delayed endolymphatic hydrops. All patients had frequent episodes of vertigo attacks which were clinically considered as of unilateral ear origin. Two types of Gd administration were used; injection into the tympanic cavity in 17 patients or intravenous injection in 10 patients. Axial 2D-FLAIR images were obtained with a 3.0T MRI unit, 24 and 4 h after intratympanic or intravenous administration, respectively. The endolymphatic space was detected as a low signal intensity area, while the surrounding perilymphatic space showed high intensity with Gd contrast. Those cases in which low signal areas corresponding to the cochlear duct could be clearly noticed, were classified as cochlear hydrops. When the greater part of the vestibule was occupied by a low signal area in more than half of the images, it was classified as vestibular hydrops. RESULTS: Endolymphatic hydrops was detected in 88% (15/17 cases) by the intratympanic Gd administration method, and 90% (9/10) by the intravenous method. In the contralateral ears, 20% (2/10) showed hydrops, detected by the intravenous method. ECochG and the glycerol test were difficult when the hearing of the patient was severely impaired. Positive results of EcochG and the glycerol test were obtained only in 15 and 6 cases, respectively. However, as far as the waves could be obtained, ECochG showed a high detection rate of 88% (15/17) in the affected ear. In those cases in which both MRI and EcochG could be obtained, including both ears, the results were matched in 78% (21/27ears). CONCLUSION: For the qualitative detection of hydrops, intratympanic and intravenous Gd administration methods were equivalent. Inner ear Gd contrast-enhanced MRI had higher efficacy in the detection of hydrops than the conventional tests.

Magnetic resonance imaging of endolymphatic hydrops: a comparison of methods with and without gadolinium-based contrast agent administration.

In the evaluation of endolymphatic hydrops (EH) using magnetic resonance (MR) imaging, hybrid of reversed image of positive endolymph signal and native image of perilymph signal multiplied with heavily T2-weighted MR cisternography (HYDROPS-Mi2) imaging with the intravenous administration of a gadolinium-based contrast agent (IV-GBCA) has been utilized. Recently, MR cisternography (MRC) without GBCA has been proposed as a potential alternative method. However, the feasibility of EH evaluation by MRC without GBCA has not been established. The present study aimed to compare HYDROPS-Mi2 imaging with IV-GBCA to MRC without IV-GBCA for the evaluation of EH. In 40 ears of 20 patients with clinically suspected EH, MRC at pre-IV-GBCA and HYDROPS-Mi2 images from 4 h post-IV-GBCA were analyzed. The saccular height on the MRC (SH-MRC) was measured. The percentage of the volume of the endolymphatic space within the whole lymphatic space of the vestibule on the HYDROPS-Mi2 image (%ELvolume-HYD) was measured. The correlation between the SH-MRC and %ELvolume-HYD was calculated. The receiver operating characteristic (ROC) of the SH-MRC and %ELvolume-HYD for the clinical diagnosis of EH was evaluated. The Spearman's rank correlation coefficient between the SH-MRC and %ELvolume-HYD was 0.102. The areas under the ROC curve were 0.570 for the SH-MRC, and 0.926 for the %ELvolume-HYD. In conclusion, there was no significant correlation between the MRC without IV-GBCA and the HYDOROPS-Mi2 with IV-GBCA in the evaluation of EH.

Differential Volume Increase of Endolymphatic Compartments in Ménière's Disease Is Inversely Associated With Membrane Thickness.

OBJECTIVES: Our aim in this study was to characterize the morphology of the endolymphatic compartment on histopathology in individuals with Ménière's disease (MD) and to determine why hydrops of the saccule is more pronounced than that of other compartments of the inner ear in MD. METHODS: Temporal bones from 9 patients with idiopathic MD and from 10 individuals without MD/endolymphatic hydrops were examined. The inner ear fluid compartments in normal ears, and ears with MD were three-dimensionally reconstructed and their volume was calculated. The thickness of the membranes of the labyrinth was measured, and both ruptures of the membranes and patency of the utriculoendolymphatic (UEV; Bast's) valve were assessed. RESULTS: In ears with MD, the saccule and the cochlear duct were most frequently hydropic; the utricle was involved approximately half as frequently. In ears without MD, the Reissner's membrane and the membranous wall of the saccule were thinner than that of the utricle and of the lateral semicircular canal ( p < 0.01). The lateral semicircular canal did not show signs of hydrops. In all ears with MD in which the utricle exceeded the average volume of normals (6 of 12), the UEV was open or there was a rupture in the utricle. CONCLUSION: Increases in endolymphatic pressure may cause a primary swelling of the apical cochlear duct and saccule, both of which have relatively thin membranes. Hydrops in the utricle may occur less frequently because of a thicker wall, because of a functioning UEV, and when the saccule has already occupied most of the vestibular perilymphatic space.

Pitfalls of Using T2-contrast Enhancement Techniques in 3D-FLAIR to Detect Endolymphatic Hydrops.

PURPOSE: To determine whether T2-contrast enhancement techniques can be used to diagnose endolymphatic hydrops, we compared fluid signal artifacts with and without T2-contrast enhancement techniques in 3D fluid-attenuated inversion recovery (3D-FLAIR). METHODS: We prepared a custom-made phantom consisting of eight tubes half-filled with saline. Images were obtained using four 3D-FLAIR: without T2-contrast enhancement (Normal), with non-selective T2-inversion recovery (T2-IR), and two with non-selective T2 preparation IR (T2-prep). Scans were performed with and without rice covering the phantom to simulate minimal and severe B0-inhomogeneity conditions. The average signal intensity (SI) values of eight saline tubes were compared between the four sequences and between each other. Comparisons were performed for all measurement slices and the central 10 slices. The images using T2-contrast enhancement technique were obtained from a volunteer and a patient suspected of Meniere's disease. RESULTS: The Normal sequence SI for all slices was significantly lower than that for the other sequences, with smaller standard deviation (SD) and no outliers. Several outliers were detected in the other sequences. The SDs and outliers were larger without rice than with rice. When the central 10 slices with rice, the T2-IR had a significantly higher SI with more outliers compared with the Normal sequence. The T2-prep had no outliers and SIs that were comparable to those of the Normal sequence. However, without rice, the T2-IR and T2-prep sequences had significantly higher SIs with outliers and larger SDs compared to the Normal sequence. In the corresponding images, the Normal sequence achieved excellent fluid suppression, whereas the T2-IR and T2-prep sequences showed high-signal artifacts. Imperfect fluid suppressions were observed in the volunteer image and the endolymphatic hydrops on the post-gadolinium image differed in size and shape in the non-injected T2-IR in the patient image. CONCLUSION: T2-contrast enhancement techniques should be used with caution in 3D-FLAIR for diagnosing endolymphatic hydrops.