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。     

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。     

人工耳蜗植入的术前评估与术中处理

目的 总结人工耳蜗植入术前评估和术中处理经验,以提高手术安全性和术后效果。方法 对158例行人工耳蜗植入患者的术前听力学与影像学信息进行评估,与术中术后结果进行比较。结果 158例人工耳蜗植入者,中耳内耳形态正常者116例,中耳内耳有异常改变42例。6例术中出现井喷,除1例井喷术前未预料外,余157例均与术前评估吻合。术后全部患者重新建立了新的听觉,平均纯音听力(声压级)37.6 dB。结论 人工耳蜗植入手术的安全性主要依靠术前影像学评估,使用高分辨率CT指导手术可以降低手术失败率,减少并发症。     

CT三维重建对人工耳蜗植入术后电极位置的观察

目的：探讨建立CT扫描及三维重建技术观察人工耳蜗植入（CI）电极的方法,并比较不同CT扫描三维重建方法的耳蜗内植入电极的影像学特征及其临床应用价值。方法：6例CI患者全部作术后CT扫描并分别应用多层面重建的容积再现（VR）、平均密度投影（AIP）、表面遮盖显示技术（SSD）3种方法进行三维重建,观察人工耳蜗植入术后耳蜗内电极。结果：3种方法的三维重建图均可直观地显示电极形态、走行及其在耳蜗内植入的深度和植入电极与内耳的空间关系,并可清晰识别耳蜗内的电极数目。结论：CT扫描三维重建方法可直接观察植入电极的形态及位置,可准确判断电极在耳蜗内电极数目,有其独特的临床应用价值。     

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。     

人工耳蜗植入术后植入电极的影像学检查

目的　探讨建立螺旋CT扫描及三维重建技术观察人工耳蜗植入电极方法 ,并比较X线摄片方法与螺旋CT扫描三维重建方法的耳蜗内电极的影像学特征及其临床应用价值。方法　 18例人工耳蜗植入患者全部作术后X线摄片检查。其中 9例用经眼眶前后位摄片 ,9例采用侧斜位 6 0°摄片。 3例患者施行术后螺旋CT扫描及内耳三维重建方法。结果　 2种投射头位的X线摄片均可显示电极形态及单个电极对 ,可间接判断电极在耳蜗内的植入深度。螺旋CT扫描三维重建图可直观地显示耳蜗形态、电极形态及其在耳蜗内植入的深度 ,可清晰识别单个电极对。结论　螺旋CT扫描三维重建方法可直观观察植入电极的形态及位置 ,可准确判断电极在耳蜗内植入的深度 ,有其独特的临床应用价值     

REZ-1人工耳蜗电极植入方法的改进研究

目的 探讨使REZ-1人工耳蜗电极靠近蜗轴的植入方法.方法 22例尸头标本CT扫描测量耳蜗直径后,植入REZ-1人工耳蜗电极,完成植入后回撤1～2个电极环,耳蜗位摄片,测量蜗轴与电极环之间距离是否有所改变.测量60例CT扫描显示一侧中耳、内耳结构正常病例的耳蜗直径.结果 22例标本中3例植入27个电极环,19例植入28个电极环.回撤电极后,与回撤前相比17例标本中第12至第19个电极环与蜗轴的距离减小(配对t检验,P<0.01),该17例标本的耳蜗直径均小于9.50 mm;而耳蜗直径大于9.60 mm的5例标本均没有出现电极环靠近蜗轴的改变.17例电极回撤后靠近蜗轴的标本耳蜗直径为9.11(0.57)mm[中位数(四分位数间距),下同],另外5例标本耳蜗卣径为9.78(0.28)mm,二者差异具有统计学意义(Mann-Whitney秩和检验,P<0.001).60例正常耳蜗直径(x±s)为(9.04±0.45)mm,90%小于9.50 mm.结论 REZ-1人工耳蜗电极植入后回撤电极的植入方法可以使耳蜗直径小于9.50 mm的患者底回内部分电极环靠近蜗轴.术前CT扫描测量耳蜗直径可以为REZ-1人工耳蜗电极选择植入方法提供帮助.     

人工耳蜗植入"井喷"的判断与术中处理的体会

目的：探讨人工耳蜗植入发生“井喷”的术前判断与术中处理的方法。方法：327例人工耳蜗植入患者术前均行颞骨高分辨CT（HRCT）筛查，并行术前准备及术中处理。结果：11例术前颞骨HRCT显示内耳畸形并发内听道底骨性缺损与耳蜗、前庭相通，术中均有脑脊液喷出，经过术中对植入口的严密封闭，术后未见脑脊液耳鼻漏等并发症的发生。结论：人工耳蜗植入发生“井喷”的原因为内耳与蛛网膜腔有异常开放的通道。术前行颞骨HRCT检查不仅能对内耳畸形的患者作出准确的判断，还能为术中进行正确的处理提供准确的科学依据，从而避免并发症的发生。     

先天性感音神经性聋患儿耳蜗大小及形态的CT研究

目的　探讨耳蜗大小及形态评估对微小耳蜗畸形诊断及人工耳蜗植入术的意义。方法　42例（84耳）CT示耳蜗结构正常的先天性极重度感音神经性聋儿童为人工耳蜗植入术（cochlear implantation,CI）组,42名（84耳）听力正常儿童为对照组,在耳蜗标准坐标系统上测量耳蜗大小：耳蜗底转长径、底转宽径、耳蜗高度、不同位置（180°、270°、360°、720°）耳蜗长度及耳蜗全长;耳蜗形态：耳蜗底转倾斜角、一二转间夹角及底转形状。比较各参数在两组间的差异。结果　CI组耳蜗大小参数均小于对照组（P <0.05）。耳蜗形态参数两组间无差异（P >0.05）。结论  耳蜗大小评估对诊断微小耳蜗畸形及人工耳蜗电极个性化选择具有指导意义,耳蜗形态评估有助于预测人工耳蜗手术难易。     

人蜗神经管高分辨CT研究

目的 为临床人工耳蜗植入术提供解剖学依据.方法 观测41例(82侧)正常人CT蜗神经管的长度和直径,观测15例(30侧)人颞骨尸头标本CT蜗神经管的长度和直径.结果 蜗神经管为位于内耳道底至耳蜗底之间的一个粗短的圆柱型管道,正常人CT蜗神经管的长度为(0.48±0.049)mm,平均直径为(1.13±0.19)mm;人颞骨尸头标本CT蜗神经管长度为(0.58±0.11)mm,平均直径为(1.26±0.16)mm.结论 将正常人与人颞骨尸头标本CT蜗神经管直径相比较,得出蜗神经管的平均值可作为人工耳蜗植入术前评估的解剖学依据.     

Radiological study of temporal bone in children with profound deafness before cochlear implant: CT vs magnetic resonance imaging]

OBJECTIVE: To evaluate the clinical application of magnetic resonance imaging (MRI) and CT in children with profound deafness before cochlear implant and their impact on surgical decision. METHODS: The pre-operative CT and MRI data from 71 children with bilateral profound deafness planned for cochlear implant were studied. RESULTS: 12 patients showed enlarged vestibular aqueduct (16.9%); 14 patients had Mondini malformation (19.7%); 3 patients demonstrated enlarged internal auditory meatus (4.2%); and 2 patients were suspected to have fistulae (2.8%) on both CT and MRI examinations. In comparison between MRI and CT, unilateral cochlear fibrosis was detected in 5 patients(7%) by MRI, but none by CT scans. Bilateral dehiscent facial nerve was detected in 1 patient(1.4%) by CT scan, while MRI was normal. CONCLUSION: CT and MRI are essential for the pre-operative planning of cochlear implant, especially in patients with enlarged vestibular aqueduct, Mondini malformation, enlarged internal auditory meatus and suspected fistulae. These two imaging modalities are complementary to each other in cases with cochlear fibrosis and facial nerve dehiscence.     

细菌性脑膜炎致聋患者内耳影像学观察及人工耳蜗置入术

目的 :了解细菌性脑膜炎后内耳MRI影像学的变化 ,及对人工耳蜗置入术的影响。方法 :细菌性脑膜炎致聋患者 5例 (10耳 )行听性脑干诱发反应 (ABR)和内耳MRI检查 ,实施人工耳蜗置入术。结果 :MRI成像检查 ,耳蜗膜迷路形态异常 5耳 ,前庭形态异常 3耳 ,半规管形态异常 8耳 ;10耳的平均听阈为 (10 2 .0± 7.1)dBHL ,手术耳的平均听阈为 (98.0± 5 .7)dBHL ,非手术耳的平均听阈为 (10 6 .0± 6 .5 )dBHL ;实施人工耳蜗置入术时 3耳没能将电极全部插入 ;发病到发现听力下降平均为 (15 .8± 15 .0 )d ,小儿较成人发现听力下降时间延迟。结论 :细菌性脑膜炎可引起不同程度的内耳形态异常 ,人工耳蜗置入术前进行MRI检查可以发现内耳形态异常的程度 ,利于正确选择术耳及手术的顺利进行     

Reversing the polarity of a cochlear implant magnet after magnetic resonance imaging

The number of patients with cochlear implant (CI) has been rapidly increasing in recent years, and these patients show a growing need of examination by magnetic resonance imaging (MRI). However, the use of MRI on patients with CI is restricted by the internal magnet of the CI. Many studies have investigated the safety of performing 1.5T MRI on patients with CI, which is now being practiced in a clinical setting. We experienced a case in which the polarity of the cochlear implant magnet was reversed after the patient was examined using 1.5T MRI. The external device was attached to the internal device oppositely. We could not find displacement of the internal device, magnet, or electrode upon radiological evaluation. We came up with two possible mechanisms by which the polarity of the magnet reversed. The first possibility was that the magnetic field of MRI reversed the polarity of the magnet. The second was that the internal magnet was physically realigned while interacting with the MRI. We believe the second hypothesis to be more reliable. A removable magnet and a loose magnet boundary of a CI device may have allowed for physical reorientation of the internal magnet. Therefore, in order to avoid these complications, first, the internal magnet must not be aligned anti-parallel with the magnetic polarity of MRI. In the Siemens MRI, the vector of the magnetic field is downward, so implant site should be placed in facing upwards to minimize demagnetization. In the GE Medical Systems MRI, the vector of the magnetic field is upward, so the implant site should be placed facing downwards. Second, wearing of a commercial mold which is fixed to the internal device before performing MRI can be helpful. In addition, any removable internal magnets in a CI device should be removed before MRI, especially in the trunk. However, to ultimately solve this problem, the pocket of the internal magnet should be redesigned for safety.     

CT diagnosis of temporal bone anomalies and cochlear implant surgery in CHARGE association

Abstract

Children with CHARGE have multiple disabilities. Impairments of vision and hearing, balance problems and facial palsy are common. Few reports have dealt with their radiological temporal bone changes and none with cochlear implant surgery. The pre-operative temporal bone computed tomography (CT) and surgical findings of one child with CHARGE and one with a CHARGE-like condition who have received cochlear implants are reported. The findings include absent semicircular canals, narrow orifice for the cochlear nerve, and abnormalities of the oval and round window, the facial canal and the ossicles. CT can be used as a diagnostic tool as these combinations of temporal bone changes are extremely rare in other materials. Cochlear implants may help these often very isolated children to communicate.     

MSCT多模态三维重建观测颞骨结构及对人工耳蜗手术的指导意义

目的 探讨采用MSCT影像三维多模态重建技术在人工耳蜗植入术术前评估、术后复查中的应用价值.方法 ①应用双阈值重建技术显示耳蜗、前庭、半规管的膜性立体结构及听小骨,颞骨透明成像,逐一融合显示听小骨、内耳与颞骨的关系;②面神经曲面重建显示面神经的走行,观察面神经与面神经隐窝、外耳道后壁、鼓索神经等邻近结构的关系;③双斜径多平面重建(MPR)技术测量鼓岬平面面神经垂直段与鼓索神经的距离.结果 该组83例,内耳畸形11例中Mondini畸形2例、半规管畸形2例、共同腔畸形2例、内听道狭窄1例、前庭导水管扩大4例.正常结构耳鼓岬平面面神经垂直段与鼓索神经距离左侧(0.270±0.057)cm,右侧(0.280±0.068)cm.术后复查5例,清晰显示植入电极位置良好.结论 多模态重建技术能较好地满足临床多角度、全方位观察中耳和内耳解剖的需要,评估手术风险,确保手术顺利进行并可应用于术后复查植入电极的位置.     

儿童人工耳蜗植入术后电诱发复合动作电位分析

目的 应用神经反应遥测(NRT)技术,观察人工耳蜗植入后不同时间段的电诱发复合动作电位(ECAP)阈值变化,探讨其对人工耳蜗术后调机的指导意义。方法 对33例使用Nucleus CI24R(CA)型人工耳蜗植入的患儿,于术中及术后1、1.5、2、4、6个月进行ECAP 阈值测试,统计分析其变化规律。结果 33例165个电极的波形检出率为93.3%。电极1、7、11、17、22的术中ECAP阈值与术后30d开机时的ECAP阈值的差异有统计学意义。同一测试电极,随术后开机时间的增长,ECAP阈值呈逐渐增加的趋势。经单因素方差分析,术后不同测试时间ECAP阈值差异有统计学意义。结论 ECAP检出率高,术中可用于检测神经反应;术后可协助估算患者的行为反应T、C级,指导调机,尤其对儿童患者更为重要。     

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.     

内听道斜矢状位磁共振成像在人工耳蜗置入术前评估中的初步应用

目的:探讨内听道(IAC)斜矢状位MRI在人工耳蜗置入术前评估中的应用价值。方法:应用斜矢状位三维快速自旋回波T2加权MRI技术对15例(30耳)拟行人工耳蜗置入术患者的IAC进行扫描。结果:所有患者顺利完成检查,IAC内神经结构显示清楚。13例蜗神经正常的患者行人工耳蜗置入术并已成功开机,2例双侧蜗神经异常者未行耳蜗置入。结论:IAC斜矢状位MRI能清晰显示IAC内蜗神经的形态、大小及IAC的大小,是人工耳蜗置入术前判断蜗神经发育状况的良好方法。