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。     

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.     

人工耳蜗植入术后X线投照位置的探讨

目的:确定耳蜗在颅骨的空间位置,设计最佳耳蜗X线摄片投照角度,用于评价电极位置。方法:测量26例耳蜗植入候选患儿术前CT和32例正常成人中内耳CT片上,耳蜗底周与正中矢状线的夹角;并根据测量的X线投射角度拍摄耳蜗位X线平片。结果:蜗轴中线与正中矢状线的角度为40°到68°,平均52.66°;其中儿童组的平均值为52.52°(s=7.07),成人组的平均值为52.80°(s=5.78),两者间差异无显著性意义(P>0.05)。结论:按所测的X线投射角度拍摄的耳蜗平片,能清晰完整显示电极系列的整体和所有的单个电极,确定电极的插入深度和准确的位置,为频率的匹配定位、语言处理方案的优化提供帮助。     

多平面重建用于人工耳蜗植入术后评估的研究北大核心CSCD

目的通过标准层面下颞骨影像重建技术对人工耳蜗植入术后内耳精细结构进行评估。方法对42例人工耳蜗植入术后病例进行颞骨CT检测,通过多平面重建(MPR)技术,在同一标准层面下观察不同电极在耳蜗内的位置、电极的覆盖角度及电极对耳蜗内精细结构(蜗轴与骨螺旋板)的影响。结果同一标准层面下不同电极在耳蜗内的位置存在差异,电极的覆盖角度不同。颞骨CT下可以观察蜗轴和骨螺旋板。精细操作下人工耳蜗植入,电极对耳蜗内精细结构损伤小。结论标准层面的MPR可以帮助准确评估电极在耳蜗中的位置,虽无法评估其对基底膜造成的损伤,但是可以评价其对蜗轴与骨螺旋板造成的影响。     

人工耳蜗植入电极插入技巧对蜗内电极位置的影响

目的　观察不同手术技巧对多导人工耳蜗植入术后蜗内电极位置的影响。方法　采用澳大利亚Nu cleus 2 4M (直电极 )、Nucleus 2 4Contour(弯电极 )以及不同的手术技巧 ,术后以改良斯氏位X线拍片 ,测量、比较蜗内电极插入的深度。结果　 59例人工耳蜗植入病例中 ,3 2例Nucleus 2 4M型人工耳蜗常规手术的电极X片显示电极在平面图上的深度为 2 68°～ 3 53° ,平均 2 78.6° ;15例Nucleus 2 4M型人工耳蜗采用改进的电极插入方法 ,术后耳蜗电极X片在平面上显示弯成 3 60°～ 445° ,平均深度 3 91.7° ;12例Nucleus 2 4Contour型人工耳蜗植入采用标准术式 ,术后蜗内电极X片在平面上显示电极弯成 3 80～ 455° ,平均 42 3°。结论　澳大利亚Nucleus 2 4M型人工耳蜗通过改良的手术技巧可使电极插入的深度更大 ,部分病例可与弯电极相似 ,Nucleus 2 4Contour型人工耳蜗的电极则更靠近蜗轴     

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。     

耳科影像自动融合技术在人工耳蜗植入后电极位置评估中的应用价值

目的 评估自动多模影像融合技术对人工耳蜗植入后电极蜗内位置评价的有效性、可靠性,并与传统影像融合重建技术相比较,讨论其在电极阶位判断中的临床价值和应用前景。方法 回顾性分析2020年1月～2021年12月于上海交通大学医学院附属第九人民医院耳鼻咽喉头颈外科门诊随访调机的人工耳蜗植入患者,收集其术前电子计算机断层扫描（computed tomography,CT）、磁共振成像（magnetic resonance imaging,MRI）及术后CT的符合医学数字成像和通信协议（digital Imaging and communications in medicine,DICOM）的数据资料,排除有耳蜗畸形或蜗神经畸形的病例。由2位耳科医师分别用传统技术和定制耳科影像分析软件（耳科精细结构图像智能处理分析软件,V 1.0）进行自动影像融合、重建及分析,评估电极位置（植入深度、电极阶位）,并记录评价时间。结果 共68例患者（109耳）纳入本研究（男32,女36）,平均年龄5.1±13.1岁。所有电极均全植入,无电极打折,1例（0.9%）发生电极穿阶,7例（6.4%）发生基底膜移位。两种评价...     

蜗轴缺失内耳形态学表现与人工耳蜗植入入路的选择

目的：总结人工耳蜗植入手术患者耳蜗蜗轴缺失的类型和人工耳蜗植入手术入路的选择,为掌握人工耳蜗植入手术的适应证提供参考。方法：人工耳蜗植入患者按术前颞骨高分辨CT检查,将存在的耳蜗蜗轴发育缺失分为3种类型：1耳蜗发育不良形成的蜗轴缺失（Mondini畸形）;2耳蜗前庭半规管发育不良（Common cavity畸形）;3内耳道与耳蜗共腔（IP-Ⅲ）畸形。将蜗轴缺失的内耳畸形人工耳蜗植入手术入路分成3种类型：Ⅰ型,常规面神经隐窝入路将圆窗扩大开放入耳蜗内;Ⅱ型,常规面隐窝入路后鼓岬表面开放入畸形的耳蜗腔内,电极沿侧壁摆放;Ⅲ型,乳突侧开放外半规管突入共腔将电极摆放于耳蜗侧的腔内骨壁。结果：1246例内耳畸形中耳蜗蜗轴发育缺失共166例,其中Mondini畸形的215例患者中存在蜗轴缺失135例;Conmon cavity畸形18例,全部存在耳蜗蜗轴缺失;内耳道与耳蜗共腔（IP-Ⅲ）畸形13例,全部存在耳蜗蜗轴缺失。2内耳畸形存在耳蜗蜗轴缺失的人工耳蜗植入手术入路的选择：Ⅰ型136例,其中Mondini畸形123例,内耳道与耳蜗共腔（IP-Ⅲ）畸形13例;Ⅱ型12例,全部为Mondini畸形存在蜗轴缺失患者;Ⅲ型18例,全部为Conmon cavity畸形。33种内耳畸形人工耳蜗植入术后效果：Mondini畸形声场测试平均为65dB,单韵母言语识别为95%,单声母言语识别为25%;Conmon cavity畸形声场测试平均为80dB,单韵母言语识别为60%,单声母言语识别为0;内耳道与耳蜗共腔（IP-Ⅲ）畸形声场测试平均为55dB,单韵母言语识别为100%,单声母言语识别为45%。结论：耳蜗蜗轴缺失的内耳畸形人工耳蜗植入术后患者听觉言语识别效果很差,Conmon cavity畸形最差,Mondini畸形次之,内耳道与耳蜗共腔（IP-Ⅲ）畸形较前两者好。     

X线平片对人工耳蜗植入电极位置判定的意义

目的 探讨X线摄片对人工耳蜗植入效果不良的原因分析和处理的指导作用.方法 对6例人工耳蜗植入效果不良的患者行耳蜗X线平片或加拍CT片检查,并根据各不同情况作相应处理.结果 病例1和2的X线耳蜗平片显爪电极化于蜗外,取出电极并再行植入术;病例3和4分别显示9个和4个电极位于蜗外遂关闭蜗外电极;病例5显示蜗内有6个电极弯折,关闭弯折处电极并采用双通道方案调试;病例6经拍片证实电极位于蜗内呈园盘状,无弯折.6例患者皆获得满意效果.结论 人工耳蜗术后常规进行耳蜗位x线平片检查可了解电极位置及形态,利于指导调试上作.     

人工耳蜗植入患者术后汉语声韵调识别能力临床分析

目的分析人工耳蜗（CI）植入患者术后普通话单音节声母、韵母、声调的识别能力差异,对比单双侧植入和植入时长对单音节识别的影响。方法选取单侧和双侧CI患者共63例,其中男35例,女28例,平均年龄（23.45±16.30）岁,CI植入时长（2.81±2.41）年。使用信度效度经已认证的单音节识别测试材料进行测试,记录每个患者声母、韵母、声调和总体的识别率得分情况。结果共获得70个测试结果：CI患者对声母、韵母和单音节总识别率均低于声调识别率且差异具有统计学意义（P=0.000 3;P=0.000 3;P=0.030 3）。对单音节总识别率超过50%的CI患者,声调识别率相比声母、韵母、单音节识别率显著性增高（P<0.005）。对于总识别率小于50%的患者,虽然声韵母识别率均低于声调识别率,但仅有韵母和声调之间差异具有统计学意义（P=0.018 9）。单双侧CI患者声调识别率差异无统计学意义(P>0.05),患者佩戴时长与单音节识别的相关性较弱。结论CI患者的声调识别效果较单音节以及声母和韵母更具有优势,声调识别会在使用CI一定时间后趋于较高水平。植入侧别对其影响较小。     

Imaging cochlear implantation with round window insertion in human temporal bones and cochlear morphological variation using high-resolution cone beam CT

Conclusions: The present experimental set-up of high spatial resolution cone-beam computed tomography (CBCT) showed advantages of demonstrating the critical landmarks of the cochlea in identifying the position of intracochlear electrode contacts and has the potential for clinical application in cochlear implant (CI) surgery. Objective: To evaluate a newly developed CBCT system in defining CI electrode array in human temporal bone and cochlear morphological variation. Methods: Standard electrode, flexible tip electrode (Flex28), and an experimental electrode array with 36 contacts from MED-EL were implanted into the cochleae of six human temporal bones through an atraumatic round window membrane insertion. The cochleae were imaged with 900 frames using an experimental set-up based on a CBCT scanner installed with Superior SXR 130-15-0.5 X-ray tube in combination with filtration of copper and aluminum. Results: In all temporal bones, the landmarks of the cochlea, modiolus, osseous spiral lamina, round window niche, and stapes were demonstrated at an average level of 3.4–4.5. The contacts of electrode arrays were clearly shown to locate in the scala tympani. There was a linear correlation between the ‘A’ value and cochlea height, and between the A value and actual electrode insertion length for the first 360° insertion depth.     

Differences of radiological artefacts in cochlear implantation in temporal bone and complete head

Abstract

Objectives

Accurate radiological evaluation of cochlear implants is essential for improvement of devices and techniques and also for assessing the position of the electrodes within the cochlea. Radiological study of implants has focused on isolated temporal bones. Previous studies showed relevant sizes of artefacts (dimensions of the radiological image compared with the actual dimensions of the electrode) in visualization of cochlear implants in computed tomography and cone beam computed tomography (CBCT). In this study, we aimed to obtain CBCT images of cochlear electrodes in isolated temporal bones and in whole heads and to assess the differences in image quality between the two.

Methods

Cochlear electrodes were implanted in three complete human heads. Radiological examinations were performed using a single CBCT scanner with varying x-ray tube currents, voltages, and rotation angles. The temporal bones were then removed and the same radiological examinations were repeated, with and without the receiver coils. Artefacts from a basal electrode (electrode 9) and an apical electrode (electrode 2) were calculated. These were compared with each other by measuring the diameter of the image of the electrode (electrode inclusive of imaging artefacts) and with the real electrode diameters from the manufacturer's data. Additionally, the radiological diameters (inclusive of artefact) of the electrodes were compared to the cross-sectional diameters of the basal and apical coils of the cochlea at the locations of these two electrodes.

Results

In comparison to the real electrode diameters, radiological artefact proportions of 51–58% for electrode 9 and 56–61% for electrode 2 were calculated. The differences between whole head images (group 1) and temporal bone images with and without the receiver coil (groups 2 and 3) were highly significant for each protocol (P < 0.001).

Discussion and conclusion

These results indicate that it is not possible reliably to determine the exact intracochlear positions of electrodes using CBCT. Imaging of isolated temporal bones produced significantly greater artefacts than imaging of the whole head. Evaluations of image quality based only on results for isolated temporal bones are not transferable to clinical situations, and should be assessed critically.     

Temporal bone results and hearing preservation with a new straight electrode

Due to improved technology, cochlear implant (CI) candidacy has been widened towards patients with usable residual hearing in the low frequency range. These patients might benefit from additional acoustic amplification provided that residual hearing can be preserved with cochlear implantation. To provide a high probability of hearing preservation, a new electrode array was designed and developed at the Medizinische Hochschule Hannover. This 'Hybrid-L' electrode array has 22 electrodes spread over 15 mm with an overall insertion depth of 16 mm. The straight electrode with modiolus facing contacts is designed for a round window insertion. It shall provide the full range of the currently most advanced Nucleus CI system. A temporal bone study demonstrated the favorable insertion characteristics and minimized trauma to intracochlear structures. Compared to standard CI electrodes especially no basilar membrane perforation could be found. So far, 4 patients have been implanted and residual hearing could be preserved. One patient was fitted and showed a marked additional benefit from the electroacoustic stimulation compared to either acoustic or electrical stimulation alone. These results are very encouraging towards a concept of reliable hearing preservation with cochlear implantation.     

Intracochle?re Elektrodenlage

Introduction

Due to the increasing number of cochlear implantations (CI), postoperative radiological verification of the electrode position, e.g., with respect to quality control, plays a central role. The aim of this study was to evaluate the intracochlear position of deep inserted electrodes by cone beam computed tomography (CBCT).

Materials and methods

CBCT data sets (Accu-I-tomo, Morita, Kyoto, Japan) of 22?patients (28?ears operated between 2008 and 2011) were retrospectively analyzed. All patients underwent a CI (round window approach) with deep insertion of the electrode (Flex soft or standard electrode from MedEl?). CBCT data were analyzed for intracochlear position of the electrode (scala vestibuli, scala tympani, malposition between the scalae) and the certainty of this evaluation.

Results

All ears could be evaluated with the status certain or relatively certain in the basal turn of the cochlea. Thereby, the electrode array was inserted into the scala tympani in 93% (n?=?26). Primary insertion into the scala vestibuli and the scala media was observed in 3.5% of the ears, respectively. In the apical part of the cochlea, only 32% (n?=?9 ears) could be evaluated with relative certainty. The remaining 68% of cases could not be evaluated. Of the 32% interpretable cases in the apical part of the cochlea, 25% (n?=?7) were inserted into the scala tympani, 3.5% (n?=?1) into the scala vestibuli, and 3.5% (n?=?1) were malpositioned between the scalae.

Conclusion

The exact evaluation of the intracochlear position of the electrode by CBCT is only possible in the basal turn of the cochlea. In deep insertion, determination of the position in the medial and apical parts of the cochlea by CBCT is still not possible. Furthermore, the round window approach allows reliable implantation into the scala tympani.     

Electrode insertion depth in cochlear implantees estimated during surgery,on plain film radiographs and with electrode function testing

Three methods of determining electrode insertion depth in cochlear implantees are studied: intraoperative counting of inserted electrodes, plain film radiography using Stenvers projection and postoperative electrode function testing. In 16 cases the number of electrodes inserted in the cochlea were counted both by the surgeon at surgery and by two independent observers on plain film radiographs using Stenvers projections. The electrode function was tested postoperatively. The differences between the three methods in estimation of the number of intracochlear electrodes were analyzed with t-tests, and 95% confidence intervals (95% CI) of the mean differences were calculated. The mean difference between the radiograph observers was 0.25 electrode (95% CI, -0.69 to 1.19 electrodes.) The mean difference between radiography observations and the surgical counts was 0.60 electrode (95% CI, -0.71 to 1.91 electrodes.) The mean difference between surgical counting and electrode function testing was 0.40 electrode (95% CI, -0.66 to 1.46 electrodes.) The mean difference between radiograph observations and electrode function testing was 0.50 electrode (95% CI, -0.51 to 1.51 electrodes.) No significant differences existed between the three methods. Our findings showed similar results in estimating electrode array insertion depth with the three methods. Plain film radiography using Stenvers projection is satisfactory if imaging is indicated for determining the number of inserted electrodes.     

Hyperbaric oxygen therapy with short duration intratympanic steroid therapy for sudden hearing loss

Conclusions. Except for basal cochlear traumatization, all specimens implanted into scala tympani showed atraumatic insertion properties and good perimodiolar electrode positioning. Cochleostomy preparation and placement can have a significant impact on levels of basal cochlear trauma. Objective. In the past, perimodiolar cochlear implant electrodes increased the risk for intracochlear traumatization when compared to free-fitting arrays. Recently, however, clinical evidence for atraumatic perimodiolar implantations with preservation of residual hearing has been described. The aim of this paper was to histologically evaluate a perimodiolar cochlear implant array for its insertion properties in cadaver human temporal bones. Surgical and electrode factors, as well as preparation artifacts influencing intracochlear trauma, were considered in the evaluation. Materials and methods. Sixteen human temporal bones were harvested up to 24 hours post mortem and implanted immediately with the Nucleus 24 Contour Advance cochlear implant electrode array. Implantations were either performed using a regular caudal approach cochleostomy or through the round window membrane. After implantation, all bones underwent special histological processing, which allowed sectioning of undecalcified bone. Insertion properties were evaluated according to a grading system. Results. Fourteen specimens were implanted into scala tympani and only two exhibited basal trauma attributable to electrode insertion characteristics. Two bones were implanted into scala vestibuli after causing trauma in the region of the cochleostomy. Insertion depths ranged from 180° to 400°. All bones showed good perimodiolar electrode positioning. Basal trauma due to surgical issues and histological artifacts was present in 10 of 16 bones.     

Mechanisms of electrode fold-over in cochlear implant surgery when using a flexible and slim perimodiolar electrode array

Objectives: This study evaluates the design of a thin perimodiolar cochlear implant electrode array (CI532) and assesses insertion-related rotation and fold-over.

Methods: The study consisted on a cochlear model and temporal bone insertion studies. Twenty insertions were studied, under four different surgical insertion conditions in vitro, the intracochlear disposition of the electrode array and presence of tip fold over were recorded. Also, eight fresh human temporal bones were studied after insertion in two conditions: correct alignment of the electrode array during the insertion and misaligned. These surgical situations were investigated within this study using a video recording of the dynamics of insertion techniques and X-ray, including fluoroscopy, Cone Beam CT, and digital imaging analysis.

Results: For electrodes inserted with a correct surgical technique, the placement was perfect, within the scala tympani. The wrapping factor was 0.53, and the perimodiolar distance was below 0.3?mm, with a mean insertion depth of 405°.

Conclusions: A perimodiolar position can be achieved with the new CI532 electrode array. The new electrode also seems to be reliable for atraumatic intracochlear placement in scala tympani (ST).     

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.     

Flat-panel computed tomography versus multislice computed tomography to evaluate cochlear implant positioning

Abstract

Objective

To evaluate and compare image quality between flat-panel volumetric computed tomography (fpVCT) and multislice CT (msCT) in temporal bones with cochlear implants (CIs), and to evaluate fpVCT imaging for accuracy in determining CI electrode positioning.

Methods

Six cadaveric temporal bones were imaged prior to CI using fpVCT. Each bone was implanted with an electrode array and rescanned in order to create radial reformatted images through each electrode contact. Electrode–modiolar interval (EMI) distances were measured. The bones were fixed and cut in order to grossly evaluate for CI intrascalar positioning and insertional trauma.

Main outcome measure

To compare image quality between fpVCT and msCT in temporal bones with CI, and to evaluate the utility of fpVCT in post-implantation temporal bone analysis.

Results

The mean EMI distances did not differ significantly between fpVCT and msCT images, while the image quality was significantly better for fpVCT. Furthermore, information about intracochlear trauma and intrascalar electrode array positioning can be ascertained using this radiographic technique.

Conclusion

fpVCT and msCT do not differ significantly in the evaluation of EMI distances in implanted temporal bones, but the image quality is significantly better using fpVCT. Additionally, useful information regarding intracochlear trauma, electrode depth of insertion, and intrascalar positioning can be gained from fpVCT imaging. Given the ease of use, superior image quality, improved convenience, reduced levels of radiation, and agreement with histology, fpVCT is a valuable option for post-implantation temporal bone imaging.