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     

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60。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。     

人工耳蜗植入术后锥体束CT影像评估

目的利用锥体束CT及多种后处理重建技术显示植入耳蜗电极位置、深度、计数植入电极数及测量离蜗轴距离,并对植入电极清晰度进行评价,探讨锥体束CT对人工耳蜗植入术(cochlear implantation, CI)后植入电极影像评估的应用价值。方法收集行CI手术患者35例,所有患者在术后行植入侧锥体束CT扫描,仪器为（VATECH）PaX Uni3D高分辨锥体束CT,管电压为：89 KV,管电流为：4.0 mA;并分别做垂直及平行于蜗轴轴位的冠状及斜矢状位的MPR图像和三维图像;计数植入电极数、测量电极深度、离蜗轴距离、评估电极位置,并进行电极清晰度的评价。结果锥体束CT可清晰显示耳蜗内电极矩阵走行,可测量电极植入深度和计数电极个数;测得植入电极共766颗,平均（21.88±2.17）颗;测定电极植入深度的平均值（19.37±1.96）mm,对比术中实际测定深度平均值（19.31±2.03）mm,两组数据差异无统计学意义（P＞0.05）。两位医生对电极清晰度的评价一致性良好（t=-0.502,P=0.619）。结论锥体束CT能显示植入电极位置、深度、计数植入电极数及测量离蜗轴的距离,可应用于临床CI术后对耳蜗内植入电极的评估。     

人工耳蜗植入术后耳蜗内电极影像学评估和应用

颞骨高分辨率CT等影像学检查能清晰显示耳蜗和内耳道的形态,已成为人工耳蜗植入(cochlearimplantation,CI)前必不可少的检查项目。随着CI的广泛开展,CI术后影像学评估越来越受到关注,检查方法从单一的二维图像向三维影像发展,观察内容从单纯评估耳蜗内电极向探讨电极位置与相关功能关系上扩展。本文就近年来CI术后耳蜗内电极影像学评估进展和应用综述如下。     

单能量去金属伪影算法重建联合重建技术在人工耳蜗CT成像质量中的评估

目的　探讨320排CT单能量去金属伪影算法重建（single-energy metal artifact reduction algorithm，SEMAR）联合多平面重建（multi-planar reformation，MPR）及最大密度投影（maximum intensity projection，MIP）两种重建技术在人工耳蜗植入（cochlear implant，CI）术后的临床评估价值。方法　对30例（34耳）CI术后患者行CT检查，对去伪影前后图像中耳蜗、电极伪影及骨结构均匀性进行评分，测量去伪影前后骨蜗管CT值。重建图像中对电极植入部位、单电极可见性进行评分，行电极计数 并与术中植入的电极数进行配对t 检验。结果　去伪影前后耳蜗、电极伪影、骨结构均匀性评分比较，差异均有统计学意义（t =-6.116、-6.371、-6.764，P 均＜0.05）；而骨蜗管CT值比较，差异无统计学意义（P＞0.05）。重建图像在电极具体植入位置、单电极评分、电极计数及术中植入的电极数与术后CT图像计数的电极数一致性好（P 均＞0.05）。结论  SEMAR可明显减轻人工耳蜗电极金属伪影，提高CT图像质量，其联合MPR及MIP有利于精准评估电极植入位置及直接进行电极计数，在CI术后的电极评估中具有较好临床应用价值。     

数字X线摄片对人工耳蜗植入电极位置的评估

目的 耳蜗数字X线摄片确定人工耳电极的位置.方法 13例植入人工耳蜗患者术后第1天行耳蜗数字X线摄片,确定人工耳蜗电极在耳蜗内的位置.结果 所有患者电极均有效植入耳蜗内,数字X线片均清楚显示耳蜗内植入的电极排列数目及电极走向,而且能辨认前庭和上半规管的形态,并可以此为标记划出参考线,以帮助计算耳蜗内电极的深度.结论 耳蜗数字X线摄片比常规耳蜗位X线片能更清楚地确定电极在耳蜗内的位置,可充分满足耳蜗植入术后影像学检查的需要,是一经济、简便和直观的方法.     

人工耳蜗植入术前听神经完整性的评估

目的 探讨、评估人工耳蜗植入候选者术前听神经完整性的检查方法;在对侧耳人工耳蜗植入术前,客观检查耳蜗发育及病变状态的检查方法。方法 对12例人工耳蜗植入候选者进行检查,根据本小组建立的人工耳蜗植入术前耳蜗影像学检查方法、术前听神经完整性检查方法及评估标准、以及术后植入电极位置的早期检查方法,结合11例人工耳蜗植入术后听觉康复疗效进行分析。结果 11例患儿满足本小组制定的人工耳蜗植入遴选标准而接受了多导人工耳蜗植入,包括1例对侧耳(第2耳)人工耳蜗植入。一例患儿因评估结果为听神经发育障碍,未作人工耳蜗植入。所有人工耳蜗植入患儿术后听觉能力皆明显改善。结论 MRI头轴位及听神经轴位和颞骨CT薄层扫描、膜迷路表层实时三维重建及膜迷路实时重建等影像学方法,结合听力学及外耳道电刺激测听反应阈与不适阈差值的电生理方法来评估听神经的完整性,对术前预测人工耳蜗植入后患儿听觉康复的可能疗效,有非常重要的意义。术后早期反斯氏位X线摄片观察蜗内植入电极部位及植入电极形态,可作为人工耳蜗电极植入成功性直观、简捷的评估方法。     

锥形束CT评估人工耳蜗植入术后电极位置与植入损伤的研究北大核心CSCD

目的 通过锥形束CT评估感音神经性耳聋患者人工耳蜗植入术(cochlear implantation,CI)后电极位置与植入损伤,为CBCT的应用提供参考。方法 选取在我科行人工耳蜗植入术的35名成人重度或极重度感音神经性耳聋患者为研究对象,年龄13-73岁,在术后3-4天均行植入侧颞骨CBCT扫描。使用NNT Viewer软件对扫描所得的DICOM数据进行后处理。观察电极位置以及植入后内耳损伤程度。结果 两款直电极植入耳蜗后均贴于耳蜗管外侧壁,81%(17/21)诺尔康CS-10A标准电极完全植入,75%(12/16)MED-EL SONATATI100标准电极完全植入。诺尔康CS-10A标准电极的平均植入深度角为366.46°±46.24°,平均植入长度为19.85mm±1.56mm,MED-EL SONATATI100标准电极的平均植入深度角为575.72°±100.33°,平均植入长度为26.66mm±4.02mm。诺尔康CS-10A标准电极植入后有1例发生骨螺旋板升高,1例发生电极从鼓阶进入前庭阶,MED-EL SONATATI100标准电极植入后有2例发生电极从鼓阶进入前庭阶。结论 CBCT具有高空间分辨率、低金属伪影、低辐射量以及成像时间短的优势,可用来评估人工耳蜗术后电极植入深度角、植入长度、电极位置、显示电极与周围结构的关系及植入后内耳损伤程度,具有较大的临床应用价值。     

成人颞骨标本植入REZ-1人工耳蜗电极后的耳蜗位摄片

目前,耳蜗位摄片是人工耳蜗植入术后判断电极植入位置的主要手段。螺旋CT虽可进行三维重建,但受到部分容积效应的影响,单个电极无法辨认清楚。本文采用耳蜗位摄片,探讨如何计数植入耳蜗内的电极个数,从而确定每个植入电极所对应的频率,为匹配频率定位、优化处理方案提供帮助。     

磁共振内耳三维重建在Ⅱ型Waardenburg综合征患者中的应用

目的探讨磁共振内耳三维重建在Ⅱ型Waardenburg综合征中的应用。方法回顾性分析2008～2011年期间行人工耳蜗植入术的6例Ⅱ型Waardenburg综合征患儿术前磁共振内耳三维重建影像学检查结果,观察内耳的发育情况及人工耳蜗植入效果。结果 2例内耳无明显异常,4例有半规管畸形,3例有耳蜗畸形,术中均顺利植入全部电极,术后均顺利开机,听觉和言语水平明显提高。结论术前磁共振内耳三维重建影像学检查可清晰显示Ⅱ型Waardenburg患者的前庭、半规管及耳蜗情况,为内耳畸形特别是耳蜗畸形患者的人工耳蜗植入手术提供指导。     

Preoperative Temporal Bone Computed Tomography Scan and Its Use in Evaluating the Pediatric Cochlear Implant Candidate

Preoperative computed tomography (CT) scan evaluation of the temporal bones in cochlear implant candidates plays a crucial role in determining candidacy and the side of implantation. The CT scans allow the surgeon to carefully review the anatomy of the inner ear and mastoid cavity in order to predict any potential difficulties or complications that may be encountered during the implant insertion. We retrospectively reviewed 50 preoperative CT scans of the temporal bone in children who have been successfully implanted. In these scans, we assessed the degree of mastoid pneumatization, cochlear anatomy and patency, size of the vestibular aqueduct, cochlear aqueduct, and internal auditory canal. We analyzed our findings and measurements and compared our results with the degree of difficulty noted in the insertion of the implant, the number of electrodes inserted in each case, and the overall complication rate. From this radiographic review, we have created a checklist for cochlear implant surgeons in order to highlight key features that need to be recognized in the temporal bone scan in preoperative evaluation of cochlear implant candidates.     

An Electric Frequency-to-place Map for a Cochlear Implant Patient with Hearing in the Nonimplanted Ear

The aim of this study was to relate the pitch of high-rate electrical stimulation delivered to individual cochlear implant electrodes to electrode insertion depth and insertion angle. The patient (CH1) was able to provide pitch matches between electric and acoustic stimulation because he had auditory thresholds in his nonimplanted ear ranging between 30 and 60 dB HL over the range, 250 Hz to 8 kHz. Electrode depth and insertion angle were measured from high-resolution computed tomography (CT) scans of the patient’s temporal bones. The scans were used to create a 3D image volume reconstruction of the cochlea, which allowed visualization of electrode position within the scala. The method of limits was used to establish pitch matches between acoustic pure tones and electric stimulation (a 1,652-pps, unmodulated, pulse train). The pitch matching data demonstrated that, for insertion angles of greater than 450 degrees or greater than approximately 20 mm insertion depth, pitch saturated at approximately 420 Hz. From 20 to 15 mm insertion depth pitch estimates were about one-half octave lower than the Greenwood function. From 13 to 3 mm insertion depth the pitch estimates were approximately one octave lower than the Greenwood function. The pitch match for an electrode only 3.4 mm into the cochlea was 3,447 Hz. These data are consistent with other reports, e.g., Boëx et al. (2006), of a frequency-to-place map for the electrically stimulated cochlea in which perceived pitches for stimulation on individual electrodes are significantly lower than those predicted by the Greenwood function for stimulation at the level of the hair cell.     

Intracochlear assessment of electrode position after cochlear implant surgery by means of multislice computer tomography

The development of electrode arrays, the past years, has focused on modiolus-hugging cochlear implant electrodes. Besides, atraumatic implantation of electrodes is of importance for the use in hearing preservation, in cases of combined electric and acoustic stimulation. Intracochlear positioning of the individual electrodes by means of multislice computer tomography (CT) has not yet been shown. In this study we formulated and tested a CT imaging protocol for postoperative scanning of the temporal bone in cochlear implant subjects. Both a fresh human temporal bone and a fresh human cadaver head were implanted with a cochlear implant. Multislice CT was performed for adequate depiction of the cochlear implant. All scans were analyzed on a viewing workstation. After mid-modiolar reconstruction we were able to identify the intracochlear electrode position relative to the scala tympani and scala vestibuli. This was possible in both the implanted isolated temporal bone and the fresh human cadaver head. The feasibility of imaging the electrode position of the cochlear implant within the intracochlear spaces is shown with multislice CT. An imaging protocol is suggested.     

Variance of angular insertion depths in free-fitting and perimodiolar cochlear implant electrodes.

OBJECTIVE: To assess the variance in cochlear implant electrode insertion depth in degrees around the modiolus (angular insertion depth) in free-fitting and perimodiolar electrode arrays. MATERIALS AND METHODS: Twenty-eight fresh human temporal bones were implanted with free-fitting cochlear implant electrodes, and 18 bones were implanted using perimodiolar electrode arrays. Specimens were embedded, and 2-dimensional radiographs were obtained to assess angular insertion depths. Histologic serial sections of undecalcified bones were then evaluated to analyze intracochlear electrode positions. Finally, linear surgical insertion depths (in millimeters) were correlated with angular insertion depth (degrees around the modiolus). RESULTS: A moderate variance of angular insertion depth was documented for both free-fitting and perimodiolar electrode arrays. Full insertions into the scala tympani ranged from 540 to 630 degrees with free-fitting arrays and from 270 to 375 degrees with perimodiolar electrodes. In free-fitting devices, a linear relationship between linear (in millimeters) and angular (degrees) insertion depths was observed. Insertions into scala vestibuli were observed in 9 of 28 and 5 of 18 of the specimens for free-fitting and perimodiolar electrodes, respectively. Additionally, scala vestibuli insertions showed greater angular insertion depths when compared with scala tympani implantations. CONCLUSION: Variances in angular insertion depths seem to be moderate and similar in free-fitting and perimodiolar electrode arrays. Scala vestibuli insertions showed greater angular insertion depths than comparable insertions into the scala tympani. In perimodiolar electrodes, angular insertion depths equal or greater than 390 degrees suggested scala vestibuli placement.     

High resolution micro-CT scanning as an innovative tool for evaluation of the surgical positioning of cochlear implant electrodes

X-ray microtomography (micro-CT) is a new technique allowing for visualization of the internal structure of opaque specimens with a quasi-histological quality. Among multiple potential applications, the use of this technique in otology is very promising. Micro-CT appears to be ideally suited for in vitro visualization of the inner ear tissues as well as for evaluation of the electrode damage and/or surgical insertion trauma during implantation of the cochlear implant electrodes. This technique can greatly aid in design and development of new cochlear implant electrodes and is applicable for temporal bone studies. The main advantage of micro-CT is the practically artefact-free preparation of the samples and the possibility of evaluation of the interesting parameters along the whole insertion depth of the electrode. This paper presents the results of the first application of micro-CT for visualization of the inner ear structures in human temporal bones and for evaluation of the surgical positioning of the cochlear implant electrodes relative to the intracochlear soft tissues.     

Astragaloside IV inhibits apoptotic cell death in the guinea pig cochlea exposed to impulse noise

X-ray microtomography (micro-CT) is a new technique allowing for visualization of the internal structure of opaque specimens with a quasi-histological quality. Among multiple potential applications, the use of this technique in otology is very promising. Micro-CT appears to be ideally suited for in vitro visualization of the inner ear tissues as well as for evaluation of the electrode damage and/or surgical insertion trauma during implantation of the cochlear implant electrodes. This technique can greatly aid in design and development of new cochlear implant electrodes and is applicable for temporal bone studies. The main advantage of micro-CT is the practically artefact-free preparation of the samples and the possibility of evaluation of the interesting parameters along the whole insertion depth of the electrode. This paper presents the results of the first application of micro-CT for visualization of the inner ear structures in human temporal bones and for evaluation of the surgical positioning of the cochlear implant electrodes relative to the intracochlear soft tissues.     

Cochlear view: postoperative radiography for cochlear implantation

OBJECTIVE: This study aimed to define a spatial position of the cochlea in the skull based on anatomical studies and to design an appropriate method of skull radiography for demonstration of the multichannel intracochlear electrode array and the structures of the inner ear, for use in evaluating the electrode position and its related pitch perception. BACKGROUND: The conventional skull radiograph (plain radiograph) can offer a complete and direct image of an intracochlear electrode array, if the x-ray is directed to the cochlea and parallel to the axis of the cochlea. METHODS: Measurement from computed tomography imaging and three-dimensional reconstruction were performed to define the spatial position of the cochlea in the skull. RESULTS: A radiographic projection, the cochlear view, was designed. A detailed radiographic method and radiologic interpretation of the cochlear view is described. An improved clinical method for measuring the longitudinal and angular position of the electrodes from the cochlear view is recommended. CONCLUSIONS: The application of the cochlear view has proved that it is beneficial postoperatively in documenting the results of cochlear implantation, and in evaluating the depth of insertion and position of individual electrodes. It serves as a valuable reference for managing frequency mapping, optimizing speech processing strategies, and further research purposes. The method can be widely used in cochlear implant clinics because of its simplicity, low radiation, speed, and minimal cost.     

Cochlear implants in forty-eight children with cochlear and/or vestibular abnormality

CT and MRI scans for 48 children with cochlear and/or vestibular abnormality were classified in decreasing severity; common cavity, Mondini plus enlarged vestibular aqueduct, Mondini dysplasia alone and enlarged vestibular aqueduct alone. No significant relationship between degree of cochlea abnormality and surgical issues (cerebrospinal fluid gusher, depth of insertion, number of electrodes) or speech perception/language outcomes was found. A significant relationship was observed between cerebrospinal fluid gusher and partial electrode insertion, fewer active electrodes and poorer sentence understanding. Optimum language outcomes were associated with younger age at implant.