磁共振成像在人工耳蜗植入术中的应用进展

人工耳蜗 (cochlearimplant,CI)模拟人的耳蜗功能 ,绕过无效的毛细胞 ,直接刺激残余的螺旋神经节细胞 ,产生听觉 ,可使重度、极重度聋患者回到有声世界。CI植入术手术径路通常是面隐窝径路 ,去除圆窗龛前缘 ,将电极由圆窗植入鼓阶。常用的植入装置有 3种 :Nucleus2 4、MedEl40     

CT与磁共振成像在儿童人工耳蜗植入术前研究

目的　评价CT与磁共振成像 (magneticresonanceimaging ,MRI)在儿童人工耳蜗植入术前的诊断作用 ,以及对手术选择的影响。方法　 71例 ( 142耳 )双耳重度耳聋、拟行人工耳蜗植入的患儿进行术前CT与MRI检查。结果　CT与MRI均发现 ,12例 ( 2 2耳 )患者有前庭水管扩大 ( 15 5 % ) ;14例 ( 2 5耳 )患儿有Mondini畸形 ( 17 6% ) ;3例 ( 5耳 )患儿有内耳道扩大 ( 3 5 % ) ;2例 ( 4耳 )患者有可疑内耳道底骨质缺损 ( 2 8% )。MRI发现有 5例 ( 5耳 )患者单侧耳蜗纤维化 ( 3 5 % ) ,而CT未见异常。1例 ( 2耳 )患儿的CT显示面神经裸露 ( 1 4% ) ,MRI正常。结论　人工耳蜗植入术前应该进行CT与MRI检查。对于发现前庭水管综合征、Mondini畸形、内耳道扩张及内耳道底骨质缺损有重要意义。这二种影像学检查结果可以相互补充诊断耳蜗纤维化与面神经裸露。对手术适应证的选择以及保证手术正常进行有重要意义     

人工耳蜗植入者颅脑磁共振成像检查一例

人工耳蜗术后行磁共振成像(magnetic resonance imaging MRI)一直被视为禁忌。近年来国外学者研究发现一定条件下，耳蜗植入者行颅脑MRI检查是安全的。我们对1例人工耳蜗植入患者行颅脑MRI扫描，报道如下。     

CT与磁共振成像在儿童人工耳蜗植入术前研究

目的 评价CT与磁共振成像（magnetic resonance imaging,MRI)在儿童人工耳蜗植入术前的诊断作用，以及对手术选择的影响。方法 71例（142耳）双耳重度耳聋、拟行人工耳蜗植入的患儿进行术前CT与MRI检查。结果 CT与MRI均发现，12例（22耳）患者有前庭水管扩大（15.5%)；14例（25耳）患儿有Mondini畸形（17.6%)；3例（5耳）患儿有内耳道扩大（3.5%)；2例（4耳）患者有可疑内耳道底骨质缺损（2.8%)。MRI发现有5例（5耳）患者单侧耳蜗纤维化（3.5%)，而CT未见异常。1例（2耳）患儿的CT显示面神经裸露（1.4%)，MRI正常。结论 人工耳蜗植入术前应该进行CT与MRI检查。对于发现前庭水管综合征、Mondini畸形、内耳道扩张及内耳道底骨质缺损有重要意义。这二种影像学检查结果可以相互补充诊断耳蜗纤维化与面神经裸露。对手术适应证的选择以及保证手术正常进行有重要意义。     

内听道狭窄的人工耳蜗植入术效果观察并文献复习

摘要：目的通过观察一例内听道狭窄患者人工耳蜗植入术后的远期康复效果,结合文献复习探讨该类畸形的手术选择指标。方法收集患儿术前听力学资料以及颞骨薄层CT资料,分别于术后半年、2年、4年时进行声场测试、MAIS量表评分、言语识别率测试分析患者康复疗效。并以内听道狭窄、蜗神经管狭窄、蜗神经孔狭窄以及蜗神经发育不良为关键词搜索与人工耳蜗康复的相关文献。结果半年时声场测试500、1 000、2 000、4 000 Hz分别为35、40、40、45 dBHL,2年时MAIS量表评分24分,4年时言语识别率80%,患儿于术后3年时言语理解能力进步明显,康复效果优于文献搜索结果。结论存在内听道狭窄的患者,人工耳蜗植入前对影像学及听力测试结果的综合分析非常重要,选择耳蜗神经发育相对较好侧以及助听效果较好侧手术,同时需坚持术后康复治疗。     

蜗神经发育不良患者人工耳蜗术前影像学评估技术及临床应用

蜗神经发育不良(Cochlear nerve deficiency,CND)是先天性极重度耳聋的原因之一,指蜗神经缺失或蜗神经纤细.CND的诊断主要依靠在3D-核磁中判断蜗神经状态,而由于技术限制,蜗神经往往显示不清.与非CND患者相比,CND患者的人工耳蜗术后效果较差,且部分患者无法从中获益.因此,提高术前CND的诊...     

蜗神经发育不良患者的人工耳蜗植入

目的:观察蜗神经发育不良的患儿人工耳蜗植入术后的效果,探讨术前HRCT和MRI对蜗神经发育不良的诊断及评估价值。方法:回顾性分析10例蜗神经发育不良患儿的术前影像学资料及人工耳蜗植入术后对声音的反应和语训效果。结果:3例(6耳)HRCT提示双侧内耳道狭窄,耳蜗、前庭和半规管发育正常,MRI提示蜗神经发育不良。7例(14耳)HRCT提示双侧内耳道正常,其中1例IP-Ⅰ型,伴前庭半规管发育不良,6例双侧耳蜗、前庭和半规管发育正常;7例MRI提示蜗神经发育异常。10例患儿均行人工耳蜗植入,经过12～32个月的随访,3例学会简单语言,MAIS量表、CAP分数及SIR分级较前提高;1例虽能讲话,但口齿含糊;4例对声音有反应,仅能说"爸爸"、"妈妈"等单音节词;2例无反应(1例取出)。10例蜗神经发育不良患儿同其他蜗神经发育正常儿童相比,术后康复情况明显落后。结论:对蜗神经缺陷患儿,术前仅做颞骨HRCT检查易漏诊,结合内耳道MRI(含内耳道斜矢状位重建)已成必须。若发现疑似病例,应慎重筛选,告知行人工耳蜗植入效果不佳的巨大可能性,严格掌握手术指征。     

咽鼓管倾斜旁矢状位磁共振成像

目的 根据咽鼓管特殊的解剖结构进行咽鼓管倾斜旁矢状位磁共振成像.方法 选取3名志愿者(男2人,女1人)进行研究.应用3.0T超导型磁共振扫描仪,采用质子密度加权成像扫描(proton densityweighted imaging,PDWI)技术进行成像.首先获得头颅正中矢状位扫描图像,然后在此基础上沿双侧咽鼓管长轴所在平面进行咽鼓管倾斜轴位扫描,在获得图像上确定垂直于咽鼓管长轴的扫描线,进行平行于咽鼓管纵断面的倾斜旁矢状位扫描.将最终获得的原始数据通过多平面重建(multiplanar reconstruction,MPR),进一步修正扫描平面,并协助进行解剖结构识别.结果咽鼓管倾斜旁矢状位MRI图像显示咽鼓管软骨清晰,周围细小结构的软组织也能够辨认.结论 临床应用3.0T超导型磁共振扫描仪进行咽鼓管倾斜旁矢状位MR扫描,成像效果满意,操作简便易行,有助于咽鼓管相关疾病的诊断.     

小儿行为听力测试在人工耳蜗植入术前评估中的应用

目的 探讨小儿行为听力测试在人工耳蜗植入中的作用。方法和结果 在我院临床听力中心1996年至2001年4月就诊的1000科名6岁以下儿童中要求植入人工耳蜗的小儿,男30例,女26例,经系统的术前的医学和听力学评估（CT或MRI、ABR、40Hz-AERP、声阻抗、耳声发射、小儿行为听力评估包括裸耳听阈和助听听阈）,植入人工耳蜗45例,10例配以助听器,1例证实为蜗后病变而随访。结论 小儿行为听力测试在人工耳蜗植入术前听力学评估很重要,可以进行手术适应证的选择、指导术后测试,并可作为术前的听觉训练。     

磁共振内耳水成像对内耳畸形患儿人工耳蜗植入术前的应用

目的　探讨磁共振内耳水成像在内耳畸形患儿人工耳蜗植入术前的评估价值。方法　回顾性分析我科85例拟行人工耳蜗植入的内耳畸形患儿的磁共振资料,结合内耳畸形的最新分类标准进行影像学分类诊断。结果85例（170耳）中有2耳Michel畸形,11耳共同腔畸形,35耳Mondini畸形,26耳半规管发育不全,98耳大前庭水管扩大,7耳显示内耳道狭窄。结论　人工耳蜗植入术前磁共振内耳水成像检查对内耳畸形患儿进行分类诊断,可以评估手术难度、指导手术方案及预后。     

Use of MRI to determine cochlear duct length in patients undergoing cochlear implantation

Objectives: It is recognised that CT can be used to determine the cochlear duct length (CDL) when selecting an electrode for cochlear implantation. It is the practice of our institution to routinely use MRI as the sole modality of pre-operative imaging in the assessment of children referred for consideration of cochlear implantation. We therefore wanted to determine whether MRI could be reliably used to determine cochlear duct length.

Methods: An analysis of 40 ears that had undergone MRI and CT of the temporal bones was undertaken. The diameter of the basal turn was independently measured for each ear using the two modalities, and CDL was then calculated.

Results: The mean error of measurement was 0.26?mm (range 0–0.8?mm), leading to a difference in calculated CDL of 0.96?mm (range 0–2.92?mm). CDL did not predict full insertion of 28?mm cochlear implant electrodes in 30 ears.

Conclusions: MRI can be used to reliably determine cochlear duct length.     

Cavernous hemangioma of the internal auditory canal

Hemangiomas rarely occur in the internal auditory canal. These tumors originate from the capillary bed of the epineurium surrounding the nerve and can either compress or infiltrate the nerve. Depending on location and the nerve of origin, these lesions can cause severe and progressive sensorineural hearing loss, tinnitus, facial nerve palsy, or vertigo even when they are relatively small. The presence of a small contrast-enhancing tumor in the internal auditory canal accompanied by severe sensorineural hearing loss and facial nerve palsy, should raise the suspicion of a hemangioma. Early recognition and surgical intervention in these benign tumors may improve the chance of preserving the functional integrity of the facial nerve and provides better results after nerve reconstruction. Due to their relative small size, the temporal bone CT-scan may show no evidence of pathological widening of the internal auditory canal or the typical intralesional calcifications at the time of presentation. MRI with Gadolinium is the imaging method of choice and a high index of clinical suspicion is necessary for the diagnosis of these tumors. In this paper we report about a 51-year-old male presented with right-sided sensory-neural deafness and facial nerve palsy, accompanied by severe tinnitus and ipsilateral loss of vestibular function due to a cavernous hemangioma in the internal auditory canal.     

The bony cochlear nerve canal in children with absent or hypoplastic cochlear nerves

Objective

To correlate presence and size of the bony cochlear nerve canal [BCNC] with size of the internal auditory meatus [IAM] on CT in children with absent or hypoplastic cochlear nerves [CNs] as compared to age matched controls.

Methods

This retrospective case-notes review was based in the departments of Cochlear Implantation and Neuroradiology at a tertiary paediatric hospital. Twenty-five ears of fifteen children (subjects) with profound sensorineural deafness (SND) and absent or hypoplastic CN on MRI scan were compared to age matched controls. Two groups of controls were included; a control group of nineteen ears of twelve children with normal hearing or conductive hearing loss [control group 1] and a second control group of twenty one ears of eleven children with severe to profound hearing loss related to GJB2 mutations [control group 2]. Both control groups had evidence of the presence of the CN. Two neuroradiologists independently assessed presence and size of BCNC and IAM on CT and presence of CN on MRI in subjects and controls. The BCNC and IAM size was compared between subjects and both control groups. The presence of BCNC was correlated with the IAM size on CT, presence/absence of CN on MRI and audiological evaluation in subjects.

Results

The mean IAM width was significantly smaller in subjects as compared to controls. The BCNC was absent in 17/25 subject ears and present in all control ears. Absent BCNC correlated with a narrow IAM in 13/17 subject ears. Presence of the BCNC supported presence of a CN although this was not seen on MRI. However, BCNC absence may be associated with presence of a CN as was seen in two subject ears. Five subject ears out of 22 [22%] with absent CN on MRI had other evidence of a present cochlear nerve.

Conclusions

BCNC is an additional parameter to assess presence of the cochlear branch of the CN. Presence of the BCNC may indicate cochlear nerve presence. Caution should be used in assessing candidacy of cochlear implants based on MRI alone and a combination of imaging and audiological tests should be used to assess presence of the CN.     

Rare tumors of the internal auditory canal

The study was performed to identify the incidence and histology of rare tumors with growth restricted to the internal auditory canal (IAC) that are different from vestibular schwannoma (VS). Furthermore, the question was addressed whether a preoperative diagnosis would be possible in these cases. A series of 351 patients that were operated on for IAC tumors through a transtemporal or translabyrinthine approach was investigated retrospectively. Cases with a tumor entity other than VS were analyzed for symptoms, radiological diagnosis, intraoperative findings and postoperative histolopatology to determine if a differential diagnosis to the common VS can be established prior to surgery. In 15 out of 351 cases (4.3%), uncommon processes of the IAC were determined by histology (6 lipomas, 3 hemangiomas, 2 neurofibromas, 2 menigiomas, 1 facial neuroma and 1 case of bilateral malignant lymphoma). The symptoms and the clinical manifestations were typical for patients with VS so that a preoperative differential diagnosis was not possible in the majority of cases. An analysis of the operation reports revealed that in 10 out of the 15 cases the surgeon suspected an unusual tumor of the IAC during surgery. The results of the present investigation suggest that rare lesions of the IAC can be expected in less than 5% of the cases and that preoperative diagnosis of rare IAC tumors is difficult. Intraoperative findings such as adhesion to cranial nerves and consistency of the tumor often indicate unusual processes, but histological analysis of the removed tissue is essential for the definite diagnosis.     

人工耳蜗植入术前的影像学检查

目的 :探讨CT和MRI检查对人工耳蜗植入术前评估的价值。方法 :对 2 6例感音性耳聋患者均采用颞骨轴位高分辨率CT螺旋扫描、MR水成像及内耳三维重建。结果 :1 8例先天性感音性耳聋患儿中检出Mondini畸形Ⅰ型 1例 (2耳 ) ,Ⅱ型 1例 (2耳 ) ,内耳纤维化 1例 (2耳 ) ;5例语后聋患者中检出慢性化脓性中耳炎 1例 (2耳 ) ,内耳骨化 1例 (2耳 )。结论 :对于人工耳蜗植入术的术前评估 ,CT检查具有重要价值 ,必不可少 ,MRI检查是必要的补充。对内耳的三维重建 ,MRI优于CT。