Ken Kato

Endolymphatic hydrops revealed by intravenous gadolinium injection in patients with Ménière's disease

CONCLUSION Visualization of endolymphatic hydrops became possible after intravenous gadolinium (Gd) injection in patients with Ménières disease. OBJECTIVE To visualize endolymphatic hydrops after intravenous Gd injection. METHODS Gd (gadoteridol; 0.2 mmol/kg) was injected intravenously in three patients with unilateral Ménières disease. We performed three-dimensional fluid attenuated inversion recovery (3D-FLAIR) and three-dimensional real inversion recovery (3D-real IR) magnetic resonance imaging (MRI) 4 h after the injection using a 3-Tesla MRI unit. We used a 32-channel array coil to obtain a high signal-to-noise ratio. RESULTS Endolymphatic hydrops was observed in the ears of patients with Ménières disease. However, Gd concentration in the perilymph was lower compared with that obtained after intratympanic Gd injection.

Endolymphatic Hydrops Revealed by Magnetic Resonance Imaging in Patients With Acute Low-Tone Sensorineural Hearing Loss

Objective Acute low-tone sensorineural hearing loss (ALHL) has been reported to be associated with endolymphatic hydrops (EHs). However, evaluation of the size of the endolymphatic space has not been reported. We attempted to visualize EH in ALHL using magnetic resonance imaging (MRI). Study Design Prospective diagnostic study. Setting University hospital. Methods We evaluated 25 ears of 25 unilateral ALHL patients. Three-tesla MRI was obtained 24 hours after intratympanic injection of gadolinium (Gd) (n = 5) or 4 hours after intravenous injection of Gd (n = 20). A radiologist blinded to the patients’ clinical data classified the degree of EH in the vestibule and cochlea into 3 groups: none, mild, and significant. Results On the affected sides, cochlear EH was recognized in 23 ears (92%) and was classified as significant EH (n = 15) or mild EH (n = 8); vestibular EH was detected in 22 ears (88%), classified as significant EH (n = 16) or mild EH (n = 6). Cochlear EH was more frequently observed in the affected ear than in the contralateral ear (90% versus 40%, p < 0.05). Conclusion In ALHL, EH was observed not only in the cochlea but also in the vestibule as in Ménière’s disease.

Impact of the Japanese Diagnosis Procedure Combination-based Payment System in Japan

In the health insurance system of Japan, a fee-for-service system has been applied to individual treatment services since 1958. This system involves a structural problem of causing an increase in examination and drug administration. A flat-fee payment system called DPC was introduced in April 2003 to solve the problems of the fee-for-service system. Based on the data of 2003 and 2004, we assessed the impact of DPC in Japan, and obtained the following conclusions: First, the introduction of DPC in Japan could not decrease the absolute value of medical costs; second, the internal efficiency of the institutions was improved, for example, by reducing the mean length of hospitalizations; third, the DPC-based diagnosis classification is considered to be effective for simplifying the medical fee system within the framework of EBM and for providing patients with information; and fourth, after introduction of the DPC, structural problems remain in the flat-fee payment system, such as examination and treatment of low quality, selection of patients and up coding. Its introduction should thus be performed with sufficient caution. We will make greater efforts to establish a better medical fee system by evaluating these problems.

Endolymphatic hydrops revealed by magnetic resonance imaging in patients with atypical Meniere's disease

Abstract Conclusion: Our study showed that patients with atypical Menieres disease had endolymphatic hydrops (EH) in both the cochlea and the vestibule. Using an imaging method, we provide evidence that atypical Menieres disease is a true variant of classic Menieres disease. Objectives: The aim of present study was to investigate images of the endolymphatic space in patients with atypical Menieres disease (cochlear and vestibular Menieres disease). Methods: Sixty-four patients divided into two groups were enrolled in this study. The first group included 36 patients who had fluctuating hearing loss without vertigo, as candidates for cochlear Menieres disease (CMD). The second group included 28 patients who had recurrent vertigo without hearing loss, as candidates for vestibular Menieres disease (VMD). The patients underwent 3 T magnetic resonance imaging (MRI) after injection of gadolinium enhancement medium intratympanically or intravenously. We evaluated EH using MRI. Results: Of 56 ears (36 patients) with CMD, 38 showed EH in the cochlea and 44 showed EH in the vestibule. Of 56 ears (28 patients) with VMD, 29 showed EH in the cochlea and 47 showed EH in the vestibule. The VMD group had a significant vestibular predominance in EH distribution whereas the CMD group showed no significant regional predominance of EH.

Association of interleukin‐1 gene polymorphisms with sudden sensorineural hearing loss and Ménière’s disease

Sudden sensorineural hearing loss (SSNHL) and Ménière’s disease are the most common inner ear diseases in which the causes are unknown. As recent magnetic resonance imaging has demonstrated disruption of the blood–labyrinth barrier in these inner ear diseases, inflammatory reaction associated with increased permeability of the blood vessels may be involved. The genotypes of interleukin 1A (IL1A) (−889C/T; rs1800587) and interleukin 1B (IL1B) (−511C/T; rs16944) were determined using an allele‐specific primer–polymerase chain reaction method in 72 patients with SSNHL, 68 patients with Ménière’s disease, and 2202 control subjects living almost in the same area as the patients. A significantly higher prevalence of the IL1A−889T allele was observed in SSNHL and Ménière’s disease compared with controls, although no significant difference in distribution of IL1B−511C/T genotypes was observed between the patients and controls. Adjusted odd ratios for SSNHL and Ménière’s disease risks in the −889TT genotypes were 25.89 (95% confidence interval (CI) 12.19–54.98) and 18.20 (95% CI 7.80–42.46), respectively, after age and gender were taken as moderator variables. Our results suggested that IL1A is closely associated with susceptibility of SSNHL and Ménière’s disease.

Polymorphisms in Genes Involved in Inflammatory Pathways in Patients with Sudden Sensorineural Hearing Loss

Abstract: Although the etiology of idiopathic sudden sensorineural hearing loss (SSNHL) remains unclear, the pathologically increased permeability of blood vessels, elucidated by gadolinium-enhanced magnetic resonance imaging (MRI), suggests the involvement of inflammation. Because SSNHL is considered a multifactorial disease, possibly caused by interactions between genetic factors and environmental factors, the authors investigated the associations of polymorphisms of inflammatory mediator genes with susceptibility to SSNHL. The authors compared 72 patients affected by SSNHL and 2010 adults (1010 men and 1000 women; mean age 59.2 years; range 40–79) who participated in the National Institute for Longevity Sciences Longitudinal Study of Aging. Multiple logistic regression was used to obtain odds ratios (ORs) for SSNHL in subjects with polymorphisms in the genes IL-6 C − 572G, IL-4R G1902A, IL-10 A − 592C, TNFα C − 863A, TNFRSF1B G593A, VEGF C936T, VEGF C − 2578A, and VEGF G − 1154A, with adjustment for age, gender, and any history of hypertension, diabetes, or dyslipidemia. The per-allele OR for the risk of SSNHL in subjects bearing IL-6 C − 572G was 1.480 (95% confidence interval [CI], 1.037–2.111) in model 1 (no adjustment), 1.463 (CI, 1.022–2.094) in model 2 (adjusted for age and gender), and 1.460 (CI, 1.016–2.097) in model 3 (adjusted for age, gender, and a history of hypertension, diabetes, or dyslipidemia). Under the dominant model of inheritance, the ORs were 1.734 (CI, 1.080–2.783) in model 1, 1.690 (CI, 1.050–2.721) in model 2, and 1.669 (CI, 1.035–2.692) in model 3. The remaining seven polymorphisms failed to show any associations with the risk of SSNHL. These data need to be confirmed on larger series of patients. In conclusion, the IL-6 C − 572G polymorphism is associated with a risk of SSNHL. Because permeability of blood vessels in the inner ear is frequently increased in patients with SSNHL, inflammation of the inner ear might be involved.

Persistent acceleration of positrons in a nonstationary shock wave

Long-time evolution of positrons accelerated in an oblique shock wave in an electron-positron-ion plasma is studied with relativistic, electromagnetic, particle simulations. In the early stage, some positrons move nearly parallel to the external magnetic field in the shock transition region and gain energy from the parallel electric field. The acceleration can become stagnant owing to the deformation of the wave profile. After the recovery of the shock profile, however, the acceleration can start again. By the end of simulation runs, ωpet=5000, positron Lorentz factors reached values ∼2000. In this second stage, three different types of acceleration are found. In the first type, the acceleration process is the same as that in the early stage. In the second type, positrons make gyromotions in the wave frame and gain energy mainly from the perpendicular electric field. In the third type, particle orbits are similar to curtate cycloids. Theoretical estimate for this energy increase is given.

Magnetic Resonance Imaging Evaluation of Endolymphatic Hydrops in Cases With Otosclerosis.

Objective Endolymphatic hydrops (EH) has been reported in cases with otosclerosis, and preoperative EH could be a risk factor for inner ear disturbances after stapes surgery. Visualization of EH has recently become possible using magnetic resonance imaging (MRI) with contrast agents. This study investigated the presence of EH on MRI in ears with clinical otosclerosis. Study design Retrospective case series. Setting University hospital. Patients 27 ears of 15 cases diagnosed with otosclerosis. Intervention Ears were evaluated by 3-T MRI performed 4 hours after intravenous injection of gadolinium. The degree of EH in the vestibule and cochlea was classified into three grades (none, mild, and significant). Imaging data were compared with clinical findings for all ears. Main Outcome Measures Imaging and clinical findings. Results Varying degrees of cochlear EH and vestibular EH were observed in 20 and 15 ears, respectively. Episodes of acute sensorineural hearing loss with rotatory vertigo occurred in four ears that showed severe EH in the cochleae and vestibules. Severe EH, however, was also observed in ears without such symptoms. Conclusions The presence of EH in ears with otosclerosis was clearly visualized in the present patient series. Such MRI evaluation could provide useful information for managing symptoms related to EH.

Peak width in multifrequency tympanometry and endolymphatic hydrops revealed by magnetic resonance imaging.

Objective To investigate the relationship between the peak width of the characteristic “M”-shaped peak of 2 kHz conductance tympanometry and the degree of endolymphatic hydrops in magnetic resonance imaging (MRI) after intratympanic or intravenous gadolinium administration. Study Design Prospective study. Setting An academic university hospital. Patients One hundred twenty-eight ears in which multifrequency tympanometry was performed and endolymphatic space size was evaluated by MRI. Forty-five patients were examined bilaterally and 38 patients were examined unilaterally. Interventions Endolymphatic space size was evaluated by MRI after intratympanic or intravenous gadolinium injection. Main Outcome Measures Endolymphatic space size was classified into three groups: none, mild, and significant in the cochlea and in the vestibule. The relationship between the degree of endolymphatic hydrops and peak width of 2 kHz conductance tympanometry was investigated. Results The peak width in 94 ears in which significant endolymphatic hydrops was observed on MRI in the cochlea and/or the vestibule was 178.8 ± 102.7 daPa. The peak width in 21 ears in which mild but not significant endolymphatic hydrops was observed on MRI in the cochlea and/or the vestibule was 126.0 ± 77.1 daPa. The peak width in 13 ears with no endolymphatic hydrops in the cochlea and vestibule was 107.1 ± 84.1 daPa. The peak width in ears with significant endolymphatic hydrops was larger than that observed in ears with no endolymphatic hydrops. However, the peak width was not significantly different between cases of mild and absent endolymphatic hydrops. Conclusion Large peak width in multifrequency tympanometry was associated with significant endolymphatic hydrops.

Polymorphisms in genes encoding aquaporins 4 and 5 and estrogen receptor α in patients with Ménière's disease and sudden sensorineural hearing loss.

AIMS The etiologies of Ménières disease and idiopathic sudden sensorineural hearing loss (SSNHL) remain unclear. The homeostasis of the water and blood circulation in the inner ear is essential for maintaining its hearing and equilibrium functions, and aquaporins and estrogen are involved in the fluid or ion balance in the inner ear. We investigated the associations between genetic polymorphisms in aquaporin 4 (AQP4, rs2075575), aquaporin 5 (AQP5, rs3736309), and estrogen receptor α (ERα1, rs2234693; ERα2, rs9340799) and susceptibility to Ménières disease or SSNHL. MAIN METHODS We compared 86 patients affected by Ménières disease, 85 patients affected by SSNHL, and 2136 adults who were participants in a comprehensive longitudinal study of aging. KEY FINDINGS With the AQP5 polymorphism, the odds ratio for Ménières disease was 0.676 (95% confidence interval: 0.477-0.957) after adjustment for age and sex, when an additive genetic model was used. The AQP5 polymorphism entailed no significant risk of SSNHL and the polymorphisms of AQP4, ERα1, and ERα2 entailed no significant risk of Ménières disease or SSNHL in the additive genetic model, regardless of adjustments for age and sex. SIGNIFICANCE Our study suggests that the variant G allele of AQP5 polymorphism rs3736309 reduces the risk of Ménières disease.