3D-FLAIR magnetic resonance imaging in the evaluation of mumps deafness

A 6-year-old boy suffered acute profound right side deafness after his classmates had mumps. Although his salivary glands were not swollen, he had high levels of anti-mumps IgM and IgG antibodies. The three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) procedure applied to magnetic resonance imaging (MRI) showed high signals in the right cochlea and vestibule. This indicated hemorrhage or a high concentration of protein in the right inner ear. This is the first case demonstrating a high 3D-FLAIR MRI signal of the inner ear in a patient with mumps deafness. Our findings suggest that 3D-FLAIR MRI may help to identify and define labyrinthitis in mumps deafness.     

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging findings in a patient with cochlear otosclerosis

A 51-year-old man had progressive hearing loss over more than 15 years. He had bilateral sensorineural hearing loss (SNHL). Computed tomography (CT) showed extensive bilateral demineralization of the cochlear capsule, which is characteristic of diffuse cochlear otosclerosis. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) of magnetic resonance imaging before enhancement revealed high signals in the cochlea and vestibule. Postcontrast 3D-FLAIR revealed enhancement of the basal turn of the left cochlea. This is the first published case of the breakdown of the blood–labyrinth barrier in a patient with cochlear otosclerosis. Our findings suggest that the breakdown of the blood–labyrinth barrier is associated with a part of SNHL in cochlear otosclerosis.     

突发性聋患者听觉中枢在功能性核磁的表现

目的 利用血氧水平依赖性的功能性磁共振成像（blood oxygen level dependent functional MRI,BOLD～fMRD技术,观察突发性聋患者在接受纯音刺激时听觉中枢的变化。方法研究对象分为两组,突发性聋患者13例（均为左耳患病）为试验组,12例双耳听力正常的健康成年志愿者作为对照组。通过CoolEditPr02软件编辑1000Hz、127dB纯音,刺激模式采用ON／OFF组块设计,通过耳机分别给予右耳及双耳音频刺激,采用荷兰Philips Achieva3．0T磁共振成像系统,采集脑部的BOLD—fMRI数据,最后通过SPM2软件对数据进行统计学分析（组分析）,得到脑功能活动的图像。结果右耳接受纯音刺激时听力正常组主要中枢激活区在双侧颞上回、左枕叶、左额上回,此外还有左小脑、双侧海马及双侧旁中央小叶激活,听觉中枢表现为右侧优势偏向;突聋组见双侧颞上回,以及左侧海马、右枕叶和左侧距状裂区激活,听觉中枢表现为左侧优势偏向,突聋组听中枢激活容积小于正常组。双耳同时刺激时,听力正常组激活区主要在双侧颞中回,右侧扣带回和左胼胝体亦明显激活;突聋组双侧颞中回,以及右侧颞上回、右小脑、右侧额下回及右楔前叶激活,两组听觉中枢均表现为右侧优势偏向。听力正常组与突聋组比较,正常组左小脑、左胼胝体区明显激活,突聋组出现新的激活区右侧颞上回、右侧额下回及右小脑区：突聋组听中枢激活容积小于正常组。结论突聋患者在单耳刺激时听觉中枢出现优势偏向的改变,提示单侧耳聋的病人听觉皮质存在着结构重组;听觉中枢具有可塑性。突聋患者在双侧刺激时通过听觉重组使双耳对外界声音的感知尽量达到正常水平;突聋患者听觉中枢不仅本身存在重组现象,且同视觉皮质之间也发生了感觉交互作用。     

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. Study Design and Methods: We used 3D‐FLAIR at 3 Tesla with and without gadolinium enhancement to evaluate the pathologic conditions in the inner ears of 48 patients with sudden SNHL. Results: Thirty‐one of 48 patients with sudden SNHL showed high signals in the affected inner ear on precontrast 3D‐FLAIR. Hearing improvement in patients with high signals in the affected inner ear on precontrast 3D‐FLAIR (25 ± 19 dB) was significantly worse than that in patients with no signal (45 ± 27 dB; P < .05). Our analysis suggests that high signals in the affected inner ear on precontrast 3D‐FLAIR MRI is a new prognostic factor for sudden SNHL. Conclusions: 3D‐FLAIR findings show that high signals in the cochlea on precontrast 3D‐FLAIR are related to a poor hearing prognosis. These signals may reflect minor hemorrhage or an increased concentration of protein in the inner ear, which has passed through blood vessels with increased permeability or has originated in disrupted cells in the inner ear.     

The clinical value of a thorough diagnostic evaluation for neurotologic complaints

Purpose

Determine the clinical efficacy of comprehensive neurotologic testing in patients presenting with complaints of hearing loss, tinnitus and/or dizziness.

Magnetic resonance imaging compatibility and safety of the SOUNDTEC Direct System

OBJECTIVE/HYPOTHESIS: The purpose of this study was to evaluate magnetic resonance imaging (MRI) compatibility and safety of an electromagnetic implanted hearing device (the SOUNDTEC Direct System; SOUNDTEC, Inc., Oklahoma City, OK) implant during a 0.3-Tesla open MRI imaging examination of the head and neck and to develop an MRI protocol that maximizes patient safety while minimizing the need for implant removal. The current literature regarding MRI compatibility of implantable hearing devices was reviewed. STUDY DESIGN: Linear and torsional forces, heating, and implant magnetization were evaluated in vitro. Implanted fresh-frozen human temporal bones were used to evaluate image distortion. A prospective study of 11 volunteers previously implanted with the SOUNDTEC Direct System was conducted to evaluate MRI compatibility and safety. A MEDLINE search of the literature between 1980 and July 2005 was reviewed to summarize MRI compatibility testing of implantable hearing devices. METHODS: Torsional and linear forces experienced by eight implant magnets were measured using calibrated neurologic Von Frey Hairs and compared with finite element analysis predictions as well as forces required to separate the incudostapedial joints of 12 fresh-frozen human temporal bones. Implant heating was determined by measuring the temperature change of eight implant vials compared with saline controls immediately after a head MRI scan. Implant magnetization was evaluated after repeated exposure to a 0.3-Tesla magnetic field. An 11-patient prospective study was performed to evaluate MRI compatibility in a 0.3-Tesla open MRI environment using adult volunteers previously implanted with the SOUNDTEC Direct System. A modified MRI protocol was developed to maximize patient safety. Each individual underwent an audiometric and otologic examination immediately before and after MRI. RESULTS: Peak linear force at the MRI entry measured 0.5 g +/- 0.2 standard deviation (SD). Maximum torque occurred at isocenter and measured 11.4 g-cm +/- 1.2 SD. The mean torque required to separate the incudostapedial joint was 33.8 g-cm +/- 20.4 SD. The average increase in temperature of the eight implant vials was 0.45 degrees C +/- 0.11 SD, whereas the increase in temperature of the three saline controls measured 0.47 degrees C +/- 0.11 SD. The average change in magnetic flux density of the 14 implant magnets tested was 22.0 gauss. Maximum image distortion occurred during the gradient echo sequence and measured 8.6 cm in diameter with a volume of 5,096 mm. Eleven patients completed a total of 12 head, one shoulder, and three lumbar 0.3-Tesla open MRI scans without patient- or device-related complications other than degradation of the MR image. There was no report of discomfort, tinnitus, dizziness, change in hearing, or change in device performance. All post-MRI changes in pure-tone thresholds, speech discrimination, soundfield thresholds, and aided soundfield thresholds were within the range of test-retest variability. CONCLUSION: When considering MRI of implantable ferromagnetic hearing devices, issues related to mechanical forces, implant heating, current induction, implant demagnetization, image degradation, and acoustic trauma must be considered. The SOUNDTEC Direct System is both MRI-compatible and safe in a 0.3-Tesla open MRI environment when a modified protocol is used. Degradation of the head MRI image may impair visualization of the ipsilateral temporal bone and adjacent structures within a 2.5- to 4.3-cm radius of the implant and is minimized by using a fast spin echo sequence.     

Auditory brainstem response versus magnetic resonance imaging for the evaluation of asymmetric sensorineural hearing loss

OBJECTIVES/HYPOTHESIS: Auditory brainstem response (ABR) testing and magnetic resonance imaging (MRI) are compared for the evaluation of patients with asymmetric sensorineural hearing loss (SNHL). MRI with gadolinium administration is the current gold standard for identifying retrocochlear lesions causing asymmetric SNHL. The study seeks to determine the sensitivity and specificity of ABR in screening for possible retrocochlear pathology. Most important among SNHL etiologies are neoplastic lesions such as vestibular schwannomas, cerebellopontine angle (CPA) tumors, as well as multiple sclerosis, stroke, or other rare nonneoplastic causes. The study results will allow the author to recommend a screening algorithm for patients with asymmetric SNHL. STUDY DESIGN: The study is a multi-institutional, institutional review board approved, prospective, nonrandomized comparison of ABR and MRI for the evaluation of patients with asymmetric SNHL. METHODS: Three hundred twelve patients (between the ages of 18 and 87) with asymmetric SNHL completed the study. Asymmetric SNHL was defined as 15 dB or greater asymmetry in two or more frequencies or 15% or more asymmetry in speech discrimination scores (SDS). These patients prospectively underwent both ABR and MRI. The ABR and MRI were interpreted independently in a blinded fashion. In addition to the ABR and MRI results, a variety of clinical and demographic data were collected. RESULTS: Thirty-one (9.94%) patients of the study population of 312 were found on MRI to have lesions causing their SNHL. Of the 31 patients with causative lesions on MRI there were 24 vestibular schwannomas, 2 glomus jugulare tumors, 2 ectatic basilar arteries with brainstem compression, 1 petrous apex cholesterol granuloma, 1 case of possible demyelinating disease, and 1 parietal lobe mass. Twenty-two of the 31 patients had abnormal ABRs, whereas 9 patients (7 with small vestibular schwannomas) had normal ABRs. This gives an overall false-negative rate for ABR of 29%. The false-positive rate was found to be 76.84%. Sensitivity of ABR as a screening test was 71%, and specificity was 74%. CONCLUSIONS: Ten percent of patients with asymmetric SNHL (by this study's criteria) are likely to have causative lesions found on MRI. Although the recently reported annual incidence of vestibular schwannoma in the general population is 0.00124%, for patients with asymmetric SNHL in this study, the incidence was 7.7% (nearly 4 orders of magnitude higher). ABR has been demonstrated to have low sensitivity and specificity in the evaluation of these patients and cannot be relied on as a screening test for patients with asymmetric SNHL. Keeping the use of MRI conditional on the results of ABR will annually result in missed or delayed diagnosis of causative lesions in 29 patients per 1,000 screened. The author recommends abandoning ABR as a screening test for asymmetric SNHL and adoption of a focused MRI protocol as the screening test of choice (within certain guidelines).     

Guidelines on the diagnosis of noise‐induced hearing loss for medicolegal purposes

These guidelines aim to assist in the diagnosis of noise‐induced hearing loss (NIHL) in medicolegal settings. The task is to distinguish between possibility and probability, the legal criterion being ‘more probable than not’. It is argued that the amount of NIHL needed to qualify for that diagnosis is that which is reliably measurable and identifiable on the audiogram. The three main requirements for the diagnosis of NIHL are defined: R1, high‐frequency hearing impairment; R2, potentially hazardous amount of noise exposure; R3, identifiable high‐frequency audiometric notch or bulge. Four modifying factors also need consideration: MF1, the clinical picture; MF2, compatibility with age and noise exposure; MF3, Robinson's criteria for other causation; MF4, complications such as asymmetry, mixed disorder and conductive hearing impairment.     

The prognostic value of the otoacoustic emission test in low frequency sudden hearing loss

Low frequency sudden hearing loss (LFSHL) is a frequent finding in the otological practice. Several prognostic indicators have been suggested concerning the prediction of the outcome of sudden hearing loss, but so far there are no proven factors to establish the prognosis. The aim of this study was to assess whether OAEs could be considered as a reliable prognostic test in LFSHL. The study group consisted of 20 patients presenting with a unilateral LFSHL. Each patient was submitted to spontaneous otoacoustic emissions (SOAEs), transient otoacoustic emissions (TEOAEs) and distortion products (DPOAEs) recording and then treated with glycerol administrated intravenously in 3-h intervals for 4 days. Pure tone audiometry (PTA) threshold was evaluated again 1 h after the last administration of glycerol. After osmotic therapy 12 patients (60%) showed a significant PTA improvement with a mean improvement of 11 dB; modifications were significant at the Students t test for paired data (P<0.0001). The relationship between the pretherapy presence or absence of SOAEs, TEOAEs and DPOAEs and PTA modification was not significant at the exact Fishers test. In conclusion, even if our study supports that OAEs could be an indicator of the inner ear functional state, they cannot be utilized as a prognostic test in LFSHL in relation to the efficacy of osmotic therapy. Among the other parameters evaluated, only the precocity of therapy seems to be related to prognosis in LFSHL.This revised version was published online in June 2004 with corrections to the names of the authors.     

Profound hearing loss attributable to cochlear nerve disease: diagnosis with combination of otoacoustic emission and magnetic resonance imaging

OBJECTIVE: To detect the causes of deafness based on the combined findings of auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAEs), and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) magnetic resonance imaging (MRI). STUDY DESIGN: Retrospective review of the medical records of 13 patients with unilateral profound hearing loss since childhood. METHODS: Subjects were tested with pure-tone audiometry, ABR, DPOAEs, and 3DFT-CISS imaging. RESULTS: No significant components of ABR were observable in any of the deaf ears. In 10 cases, the cochlear nerves of the deaf ears were found to be as normal as the healthy sides by 3DFT-CISS imaging, and no significant levels of DPOAEs were recorded. In the other three cases, no apparent cochlear nerves were identified by 3DFT-CISS imaging. Although no significant levels of DPOAEs were observable in two cases with cochlear nerves invisible by the MRI study, almost the same level of DPOAEs as that in the healthy side was recorded in the last case. CONCLUSIONS: In the last particular case, the cochlear nerve seemed to be mainly responsible for the profound deafness. 3DFT-CISS imaging in combination with preexisting audiological measures may provide direct evidence for the cochlear nerve disease. steady state, internal auditory canal, cochlear nerve disease.     

Diagnostic evaluation of magnetic resonance imaging with turbo inversion recovery sequence in head and neck tumors

The clinical outcome of patients with head and neck cancer depends on many factors such as tumor size, metastatic involvement and angioarchitecture of the tumor. The correct staging of tumor extension, presence of cervical lymph node metastases and evaluation of vascular infiltration are essential diagnostic steps before treatment. The aim of this study was to evaluate the accuracy of turbo inversion recovery magnitude (TIRM) magnetic resonance imaging (MRI) in the diagnosis of head and neck tumors with special attention to tumor size and tumor spread according to the current TNM classification. TIRM sequence with short T1 relaxation and long TE (echo time) improves imaging contrast because of the increased T1-weighting and the inherent fat suppression. In a prospective clinical study, 32 patients underwent preoperative MRI. Diagnosis was confirmed histologically in all cases. Scanning was performed on a 1.0-T unit applying TIRM as well as T1- and T2-weighted turbo spin echo (TSE) sequences. In all sequences, tumor size was overestimated due to reactive inflammatory changes surrounding the tumor tissue. The least overestimation was documented on TIRM and post-contrast T1 TSE. The highest values of relative tumor signal intensities were obtained in TIRM (3.5±0.9) and T2 TSE (3.5±0.8) followed by post-contrast T1 TSE (1.6±0.7) and pre-contrast T1 TSE (1.2±0.3). Due to the inherent fat suppression, tumor delineation was most obvious in TIRM. In patients with suspected cancer of the head and neck, TIRM should be considered as a standard and a diagnostically relevant sequence in the MRI staging protocol.     

喉癌MRI分期评价

目的评价ＭＲＩ在喉癌术前Ｔ分期中的价值。方法对５９例喉癌的ＭＲＩ资料进行回顾性分期，并与纤维喉镜及手术病理对照。结果ＭＲＩ对各期喉癌分期的准确性分别是：Ｔ１：９５％（２０／２１），Ｔ２：８８％（１５／１７），Ｔ３：８５％（１１／１３）Ｔ４：１００％（８／８）。纤维喉镜分期的准确性是：Ｔ１：９１％（１９／２１），Ｔ２：８８％（１５／１７），Ｔ３：４７％（８／１３），Ｔ４：１３％（１／８）。结论ＭＲＩ能准确判断会厌前间隙（ＰＥＳ）、喉旁间隙（ＰＧＳ）浸润及软骨破坏，因而可显著提高喉癌术前分期的准确性，对临床治疗方案选择具有重要意义。     

1例耳蜗前庭神经畸形患者耳蜗植入术前的功能性磁共振评估并文献复习

目的:探讨功能性磁共振(fMRI)评价耳蜗前庭神经畸形患者是否有人工耳蜗植入指征的可能性。方法:对1例15岁双侧耳聋患者,在人工耳蜗植入前进行听力学、影像学检查及fMRI综合评估。结果:纯音测听和听觉脑干反应显示患者为双侧极重度感音神经性聋,瞬态诱发性耳声发射双侧均未引出。颞骨薄层CT显示内耳畸形(不全分隔Ⅰ型),MRI斜矢状位重建显示耳蜗前庭神经畸形。fMRI显示左耳给声,1000Hz100dBHL,右侧听皮层被激活;右耳给声,双侧听皮层均未见激活。左侧人工耳蜗植入术后1个月开机,患者对声音有反应。结论:结合听力学和影像学检查,fMRI可评估人工耳蜗植入候选者,尤其是在影像学检查显示患者耳蜗前庭神经发育畸形时,更是一种有效的评估方法。     

Safety of magnetic resonance imaging of stapes prostheses

OBJECTIVE: Assess the safety of performing magnetic resonance imaging (MRI) on patients with stapes prostheses. STUDY DESIGN: Survey and animal model. METHODS: A survey regarding implant usage, MRI procedures, and adverse outcomes after MRI in patients previously undergoing stapes procedures. Guinea pigs implanted with ferromagnetic 17 to 4 stainless steel, 316L nonferromagnetic stainless steel, titanium, and fluoroplastic stapes prostheses underwent a MRI in a 4.7 Tesla MR system. RESULTS:: Three adverse outcomes were reported on the clinical survey. One adverse event occurred during an MRI performed on a recalled ferromagnetic prosthesis. The other two adverse events were probably not secondary to MRI exposure. No damage or inflammation was observed in the region of the oval window or vestibule of implanted guinea pigs exposed to a 4.7 Tesla MR system. CONCLUSIONS: The combination of prior studies, the clinical survey, and the absence of histopathologic evidence of damage in the guinea pigs is compelling evidence that MRI for patients with stapes prostheses is safe. Implanting physicians should feel comfortable clearing a patient for a MRI in a 1.5 Tesla or 3.0 Tesla MRI. It is imperative for the physician to qualify the field strength when clearing a patient to undergo a MRI.