Tsutomu Nakashima

Visualization of Endolymphatic Hydrops in Patients With Meniere's Disease†

Objective: Recently, there have been many reports of intratympanic gentamicin therapy for the treatment of intractable Menieres disease. Intratympanic administration of steroids has also been used to treat sudden sensorineural hearing loss. We attempted to visualize how the intratympanically administered drug enters the inner ear.

Disorders of cochlear blood flow

The cochlea is principally supplied from the inner ear artery (labyrinthine artery), which is usually a branch of the anterior inferior cerebellar artery. Cochlear blood flow is a function of cochlear perfusion pressure, which is calculated as the difference between mean arterial blood pressure and inner ear fluid pressure. Many otologic disorders such as noise-induced hearing loss, endolymphatic hydrops and presbycusis are suspected of being related to alterations in cochlear blood flow. However, the human cochlea is not easily accessible for investigation because this delicate sensory organ is hidden deep in the temporal bone. In patients with sensorineural hearing loss, magnetic resonance imaging, laser-Doppler flowmetry and ultrasonography have been used to investigate the status of cochlear blood flow. There have been many reports of hearing loss that were considered to be caused by blood flow disturbance in the cochlea. However, direct evidence of blood flow disturbance in the cochlea is still lacking in most of the cases.

Grading of endolymphatic hydrops using magnetic resonance imaging

Conclusion: Grading of endolymphatic hydrops in the vestibule and the cochlea using magnetic resonance imaging (MRI) is proposed (2008 Nagoya scale). Objective: To standardize the evaluation of endolymphatic hydrops in both the vestibule and the cochlea using MRI. Patients and methods: The endolymphatic space was evaluated after intratympanic gadolinium injection using three-dimensional fluid attenuated (3D-FLAIR) MRI and three-dimensional real inversion recovery (3D-real IR) MRI. Results: A simple three-stage grading system was acceptable for hydrops in both the vestibule and the cochlea: none, mild, and significant. In the vestibule, the grading was determined by the ratio of the area of endolymphatic space to the vestibular fluid space (sum of the endolymphatic and perilymphatic spaces). Patients with no hydrops have a ratio of one-third or less, those with mild hydrops have between one-third and a half, and those with significant hydrops have a ratio of more than 50%. In the cochlea, patients classified as having no hydrops show no displacement of Reissners membrane; those with mild hydrops show displacement of Reissners membrane but the area of the endolymphatic space does not exceed the area of the scala vestibuli; and in those with significant hydrops the area of the endolymphatic space exceeds the area of the scala vestibuli.

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging findings and prognosis in sudden sensorineural hearing loss.

Objectives/Hypothesis: Three‐dimensional fluid‐attenuated inversion recovery (3D‐FLAIR) magnetic resonance imaging (MRI) has recently been developed to detect high concentrations of protein or hemorrhage. We have previously reported that 50% of patients with sudden sensorineural hearing loss (SNHL) show high signals in the affected inner ear on 3D‐FLAIR MRI. However, the relationship between 3D‐FLAIR findings and hearing prognosis is unclear. Our objective was to evaluate the relationship between the results of 3D‐FLAIR MRI at 3 Tesla and prognosis in sudden SNHL.

Separate visualization of endolymphatic space, perilymphatic space and bone by a single pulse sequence; 3D-inversion recovery imaging utilizing real reconstruction after intratympanic Gd-DTPA administration at 3 Tesla

Twenty-four hours after intratympanic administration of gadolinium contrast material (Gd), the Gd was distributed mainly in the perilymphatic space. Three-dimensional FLAIR can differentiate endolymphatic space from perilymphatic space, but not from surrounding bone. The purpose of this study was to evaluate whether 3D inversion-recovery turbo spin echo (3D-IR TSE) with real reconstruction could separate the signals of perilymphatic space (positive value), endolymphatic space (negative value) and bone (near zero) by setting the inversion time between the null point of Gd-containing perilymph fluid and that of the endolymph fluid without Gd. Thirteen patients with clinically suspected endolymphatic hydrops underwent intratympanic Gd injection and were scanned at 3 T. A 3D FLAIR and 3D-IR TSE with real reconstruction were obtained. In all patients, low signal of endolymphatic space in the labyrinth on 3D FLAIR was observed in the anatomically appropriate position, and it showed negative signal on 3D-IR TSE. The low signal area of surrounding bone on 3D FLAIR showed near zero signal on 3D-IR TSE. Gd-containing perilymphatic space showed high signal on 3D-IR TSE. In conclusion, by optimizing the inversion time, endolymphatic space, perilymphatic space and surrounding bone can be separately visualized on a single image using a 3D-IR TSE with real reconstruction.

Vestibular and Cochlear Toxicity of Aminoglycosides - A review

Recently, there have been many reports describing the efficacy of intratympanic aminoglycoside injection for the treatment of intractable vertigo in patients with Ménières disease. However, the number of injections and the amount of drug injected varies, with concomitant variation in the side-effect of hearing deterioration. To identify drugs that are more selectively vestibulotoxic, we have reviewed the ototoxicity of aminoglycosides, focusing on differences between vestibulo- and cochleotoxicity. At present, the basis for the different effects of each drug is unknown. The mechanisms of vestibulo- and cochleotoxicity are deemed worthy of further study.Recently, there have been many reports describing the efficacy of intratympanic aminoglycoside injection for the treatment of intractable vertigo in patients with Ménières disease. However, the number of injections and the amount of drug injected varies, with concomitant variation in the side-effect of hearing deterioration. To identify drugs that are more selectively vestibulotoxic, we have reviewed the ototoxicity of aminoglycosides, focusing on differences between vestibulo- and cochleotoxicity. At present, the basis for the different effects of each drug is unknown. The mechanisms of vestibulo- and cochleotoxicity are deemed worthy of further study.

Ménière's disease: a reappraisal supported by a variable latency of symptoms and the MRI visualisation of endolymphatic hydrops

Objectives To evaluate the onset of vertigo, hearing loss and tinnitus in Ménières disease and the associated endolymphatic hydrops (EH) of the inner ear. Design Multicentre evaluation of three patient groups. Settings Disease-specific symptoms were reviewed among referred patients in a tertiary referral hospital in Finland and in members of a Finnish Ménière Association in Finland. The MRI of a separate group of patients was undertaken in a tertiary referral centre in Japan. Participants 340 patients were reviewed in the referral hospital along with 740 members of the Ménière Association. MRI was undertaken in 224 patients in Japan. Primary and secondary outcome measures Latency and symptom development in Ménières disease, and the appearance of EH of the inner ear in monosymptomatic patients and in Ménières disease. Results The mean age of the first symptom was 43.8 years, with 10% of the patients being older than 65 years. The time delay between hearing loss and vertigo was more than 5 years in 20% of the members and of the patients. Gadolinium-contrasted MRI demonstrated EH in 90% of the patients with Ménières disease, in which 75% was bilateral among patients with unilateral symptoms. In monosymptomatic patients with vertigo, tinnitus or hearing loss; EH was demonstrated in 55–90% of the patients either in the cochlea and/or the vestibulum of the symptomatic ear. Conclusions Ménières disease often shows bilateral EH and comprises a continuum from a monosymptomatic disease to the typical symptom complex of the disease. We suggest that a 3T MRI measurement should be carried out in patients with sensory-neural hearing loss, vertigo and tinnitus, 4 h after the intravenous injection of a gadolinium-contrast agent to verify the inner ear pathology. This may lead to a better management of the condition.

Individual Differences in the Permeability of the Round Window: Evaluating the Movement of Intratympanic Gadolinium Into the Inner Ear

Objective: Many recent studies have reported on intratympanic gentamicin therapy for the treatment of intractable Ménières disease. Intratympanic administration of steroids has also been used to treat sudden sensorineural hearing loss. These intratympanic drug therapies are based on the assumption that the drug administered intratympanically enters the inner ear through the round window membrane. We used magnetic resonance imaging (MRI) to evaluate whether and how intratympanically administered gadolinium (Gd) enters the inner ear. Methods: GD hydrate was injected intratympanically through the tympanic membrane using a 23-G needle into 61 ears of 55 patients with inner ear diseases. The injected Gd was diluted 8-fold in saline for injection into 58 ears and 16-fold for 3 ears. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging was performed using a 3-Tesla MRI unit 1 day after the intratympanic injection. Results: In 53 of 61 ears, the Gd-containing inner ear was detected well as a high signal on 3D-FLAIR imaging. However, Gd was not visible in 2 ears with Ménières disease and in 1 ear with profound deafness. The concentration of Gd in the perilymph was lower in 4 ears with Ménières disease and 1 ear with delayed endolymphatic hydrops than after intratympanic administration of the 16-fold Gd dilution. Conclusion: Round window permeability was absent in 5% of ears, and 13% of ears had poor round window permeability. These results should be considered when planning intratympanic drug administration therapy to treat inner ear diseases.

Imaging of Endolymphatic and Perilymphatic Fluid at 3T After Intratympanic Administration of Gadolinium-Diethylene-Triamine Pentaacetic Acid

SUMMARY: By optimizing the inversion time of a 3D inversion-recovery turbo spin-echo sequence at 3T, we obtained separate images of endolymphatic and perilymphatic space 24 hours after intratympanic administration of gadolinium contrast material. In patients with Ménière disease, endolymphatic hydrops were detected not only in the cochlea but also in the vestibule. Fusion of the 2 types of images visualized the entire fluid space of the labyrinth and the spatial relationship of the 2 spaces.

Thirty-year trends in sudden deafness from four nationwide epidemiological surveys in Japan.

Conclusions. The estimated annual number of patients with sudden deafness treated in Japan has increased during the last 30 years, especially in the elderly population. Hypertension and diabetes mellitus could contribute to the etiology of this disorder. Objectives. To investigate the epidemiological trends of sudden deafness in Japan over the past 30 years by analyzing data from national surveys. Materials and methods. Nationwide epidemiological surveys on sudden deafness were conducted four times by the Research Committee of the Ministry of Health and Welfare in Japan. The first, second, third, and fourth surveys were performed in 1972, 1987, 1993, and 2001, respectively. Results. The estimated annual numbers of patients with sudden deafness treated in Japan were 4000 in 1972; 16 700 in 1987; 24 000 in 1993, and 35 000 in 2001.The average ages of patients at onset were 39.1, 45.4, 49.3, and 51.3 years, respectively. Thus, both the number of patients and the average age of patients with sudden deafness have increased during the past 30 years. Patients with sudden deafness in the fourth survey exhibited hypertension and diabetes mellitus more frequently than did patients in the first survey; this trend was particularly noticeable among elderly patients.