Synchrotron radiation X-ray microtomography for the visualization of intra-cochlear anatomy in human temporal bones implanted with a perimodiolar cochlear implant electrode array

2021 ◽  
Vol 28 (1) ◽  
pp. 327-332
Author(s):  
Fergio Sismono ◽  
Lucia Mancini ◽  
Marc Leblans ◽  
Jana Goyens ◽  
Glynnis De Greve ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Cochlear Implant ◽  
Three Dimensional ◽  
Electrode Array ◽  
Standard Technique ◽  
Electrode Arrays ◽  
Contrast Imaging ◽  
Histological Techniques ◽  
Hearing Research ◽  
Temporal Bones

Recently, synchrotron radiation computed microtomography (SRµCT) has emerged as a promising tool for non-destructive, in situ visualization of cochlear implant electrode arrays inserted into a human cochlea. Histological techniques have been the `gold standard' technique for accurate localization of cochlear implant electrodes but are suboptimal for precise three-dimensional measurements. Here, an SRµCT experimental setup is proposed that offers the benefit of a high spatial and contrast resolution (isotropic voxel size = 4.95 µm and propagation-based phase-contrast imaging), while visualizing the soft-tissue structures and electrode array of the cochlear implant simultaneously. In this work, perimodiolar electrode arrays have been tested, which incorporate thick and closely spaced platinum–iridium contacts and wiring. These data can assist cochlear implant and hearing research, can be used to verify electrode segmentation techniques for clinical computed tomography or could be utilized to evaluate cochlear implant electrode array designs.

scholarly journals Evaluation of the Efficacy of Dexamethasone-Eluting Electrode Array on the Post-Implant Cochlear Fibrotic Reaction by Three-Dimensional Immunofluorescence Analysis in Mongolian Gerbil Cochlea

2021 ◽  
Vol 10 (15) ◽  
pp. 3315
Author(s):  
Philippine Toulemonde ◽  
Michaël Risoud ◽  
Pierre Emmanuel Lemesre ◽  
Cyril Beck ◽  
Jean Wattelet ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Dimensional Analysis ◽  
Mongolian Gerbil ◽  
Three Dimensional ◽  
Electrode Array ◽  
Light Sheet ◽  
Tissue Response ◽  
Electrode Arrays ◽  
Immunofluorescence Analysis ◽  
Light Sheet Microscopy

Cochlear implant is the method of choice for the rehabilitation of severe to profound sensorineural hearing loss. The study of the tissue response to cochlear implantation and the prevention of post-cochlear-implant damages are areas of interest in hearing protection research. The objective was to assess the efficacy of dexamethasone-eluting electrode array on endo canal fibrosis formation by three-dimensional immunofluorescence analysis in implanted Mongolian gerbil cochlea. Two trials were conducted after surgery using Mongolian gerbil implanted with dexamethasone-eluting or non-eluting intracochlear electrode arrays. The animals were then euthanised 10 weeks after implantation. The cochleae were prepared (electrode array in place) according to a 29-day protocol with immunofluorescent labelling and tissue clearing. The acquisition was carried out using light-sheet microscopy. Imaris software was then used for three-dimensional analysis of the cochleae and quantification of the fibrotic volume. The analysis of 12 cochleae showed a significantly different mean volume of fibrosis (2.16 × 108 μm3 ± 0.15 in the dexamethasone eluting group versus 3.17 × 108 μm3 ± 0.54 in the non-eluting group) (p = 0.004). The cochlear implant used as a corticosteroid delivery system appears to be an encouraging device for the protection of the inner ear against fibrosis induced by implantation. Three-dimensional analysis of the cochlea by light-sheet microscopy was suitable for studying post-implantation tissue damage.

scholarly journals Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Graziela de Souza Queiroz Martins ◽  
Rubens Vuono Brito Neto ◽  
Robinson Koji Tsuji ◽  
Eloisa Maria Mello Santiago Gebrim ◽  
Ricardo Ferreira Bento
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Minimal Trauma ◽  
Electrode Insertion ◽  
Temporal Bones

Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane.Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation.Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arraysin situ. The resulting images were analyzed for signs of intracochlear trauma.Results. Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion.Conclusions. The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.

scholarly journals The Importance of Intraoperative Plain Radiographs during Cochlear Implant Surgery in Patients with Normal Anatomy

2021 ◽  
Vol 11 (9) ◽  
pp. 4144
Author(s):  
Ohad Cohen ◽  
Jean-Yves Sichel ◽  
Chanan Shaul ◽  
Itay Chen ◽  
J. Thomas Roland ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Electrode Array ◽  
Cost Effective ◽  
X Rays ◽  
Normal Anatomy ◽  
Electrode Arrays ◽  
Plain Radiographs ◽  
Hearing Function ◽  
Tertiary Center ◽  
Cochlear Implant Surgery

Although malpositioning of the cochlear implant (CI) electrode array is rare in patients with normal anatomy, when occurring it may result in reduced hearing outcome. In addition to intraoperative electrophysiologic tests, imaging is an important modality to assess correct electrode array placement. The purpose of this report was to assess the incidence and describe cases in which intraoperative plain radiographs detected a malpositioned array. Intraoperative anti-Stenver’s view plain X-rays are conducted routinely in all CI surgeries in our tertiary center before awakening the patient and breaking the sterile field. Data of patients undergoing 399 CI surgeries were retrospectively analyzed. A total of 355 had normal inner ear and temporal bone anatomy. Patients with intra or extracochlear malpositioned electrode arrays demonstrated in the intraoperative X-ray were described. There were four cases of electrode array malposition out of 355 implantations with normal anatomy (1.1%): two tip fold-overs, one extracochlear placement and one partial insertion. All electrodes were reinserted immediately; repeated radiographs were normal and the patients achieved good hearing function. Intraoperative plain anti-Stenver’s view X-rays are valuable to confirm electrode array location, allowing correction before the conclusion of surgery. These radiographs are cheaper, faster, and emit much less radiation than other imaging options, making them a viable cost-effective tool in patients with normal anatomy.

scholarly journals Vascular Supply of the Human Spiral Ganglion: Novel Three-Dimensional Analysis Using Synchrotron Phase-Contrast Imaging and Histology

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xueshuang Mei ◽  
Rudolf Glueckert ◽  
Annelies Schrott-Fischer ◽  
Hao Li ◽  
Hanif M. Ladak ◽  
...  
Keyword(s):  
Blood Supply ◽  
Phase Contrast ◽  
Spiral Ganglion ◽  
Three Dimensional ◽  
Vascular Anatomy ◽  
Helical Structure ◽  
Vascular Supply ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Temporal Bones

AbstractHuman spiral ganglion (HSG) cell bodies located in the bony cochlea depend on a rich vascular supply to maintain excitability. These neurons are targeted by cochlear implantation (CI) to treat deafness, and their viability is critical to ensure successful clinical outcomes. The blood supply of the HSG is difficult to study due to its helical structure and encasement in hard bone. The objective of this study was to present the first three-dimensional (3D) reconstruction and analysis of the HSG blood supply using synchrotron radiation phase-contrast imaging (SR-PCI) in combination with histological analyses of archival human cochlear sections. Twenty-six human temporal bones underwent SR-PCI. Data were processed using volume-rendering software, and a representative three-dimensional (3D) model was created to allow visualization of the vascular anatomy. Histologic analysis was used to verify the segmentations. Results revealed that the HSG is supplied by radial vascular twigs which are separate from the rest of the inner ear and encased in bone. Unlike with most organs, the arteries and veins in the human cochlea do not follow the same conduits. There is a dual venous outflow and a modiolar arterial supply. This organization may explain why the HSG may endure even in cases of advanced cochlear pathology.

Electrode design and insertional depth-dependent intra-cochlear pressure changes: a model experiment

2017 ◽  
Vol 132 (3) ◽  
pp. 224-229 ◽  
Author(s):  
P Mittmann ◽  
A Ernst ◽  
I Todt
Keyword(s):  
Cochlear Implant ◽  
Fluid Pressure ◽  
Electrode Array ◽  
Lateral Wall ◽  
Peak Frequency ◽  
Peak Amplitude ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Pressure Peak ◽  
Pressure Changes

AbstractBackground:Preservation of residual hearing is one of the major goals in modern cochlear implant surgery. Intra-cochlear fluid pressure changes influence residual hearing, and should be kept low before, during and after cochlear implant insertion.Methods:Experiments were performed in an artificial cochlear model. A pressure sensor was inserted in the apical part. Five insertions were performed on two electrode arrays. Each insertion was divided into three parts, and statistically evaluated in terms of pressure peak frequency and pressure peak amplitude.Results:The peak frequency over each third part of the electrode increased in both electrode arrays. A slight increase was seen in peak amplitude in the lateral wall electrode array, but not in the midscalar electrode array. Significant differences were found in the first third of both electrode arrays.Conclusion:The midscalar and lateral wall electrode arrays have different intra-cochlear fluid pressure changes associated with intra-cochlear placement, electrode characteristics and insertion.

Visualization of mouse spinal cord intramedullary arteries using phase- and attenuation-contrast tomographic imaging

2016 ◽  
Vol 23 (4) ◽  
pp. 966-974 ◽  
Author(s):  
Yong Cao ◽  
Xianzhen Yin ◽  
Jiwen Zhang ◽  
Tianding Wu ◽  
Dongzhe Li ◽  
...  
Keyword(s):  
Spinal Cord ◽  
High Resolution ◽  
Synchrotron Radiation ◽  
Three Dimensional ◽  
Small Vessel ◽  
Imaging Method ◽  
Central Sulcus ◽  
Contrast Imaging ◽  
Mouse Spinal Cord ◽  
Small Vessels

Many spinal cord circulatory disorders present the substantial involvement of small vessel lesions. The central sulcus arteries supply nutrition to a large part of the spinal cord, and, if not detected early, lesions in the spinal cord will cause irreversible damage to the function of this organ. Thus, early detection of these small vessel lesions could potentially facilitate the effective diagnosis and treatment of these diseases. However, the detection of such small vessels is beyond the capability of current imaging techniques. In this study, an imaging method is proposed and the potential of phase-contrast imaging (PCI)- and attenuation-contrast imaging (ACI)-based synchrotron radiation for high-resolution tomography of intramedullary arteries in mouse spinal cord is validated. The three-dimensional vessel morphology, particularly that of the central sulcus arteries (CSA), detected with these two imaging models was quantitatively analyzed and compared. It was determined that both PCI- and ACI-based synchrotron radiation can be used to visualize the physiological arrangement of the entire intramedullary artery network in the mouse spinal cord in both two dimensions and three dimensions at a high-resolution scale. Additionally, the two-dimensional and three-dimensional vessel morphometric parameter measurements obtained with PCI are similar to the ACI data. Furthermore, PCI allows efficient and direct discrimination of the same branch level of the CSA without contrast agent injection and is expected to provide reliable biological information regarding the intramedullary artery. Compared with ACI, PCI might be a novel imaging method that offers a powerful imaging platform for evaluating pathological changes in small vessels and may also allow better clarification of their role in neurovascular disorders.

scholarly journals Three-dimensional Construction of Micrometer Level in Rat Stomach by Synchrotron RadiationThree-dimensional Construction of Micrometer Level in Rat Stomach by Synchrotron Radiation

2020 ◽  
Author(s):  
Qiang Tao ◽  
Chen-Chen Gao ◽  
Xue-Hong Tong ◽  
Shizhen Yuan ◽  
Tian-tian Wang ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Image Resolution ◽  
Phase Contrast Imaging ◽  
Imaging Method ◽  
Rat Stomach ◽  
Contrast Imaging ◽  
X Ray ◽  
3 Dimensional

Abstract Objectives This article shows an imaging method of the stomach that does not use imaging agents. X-ray phase-contrast images of different stages of gastric development were taken using X-ray in-line phase-contrast imaging (XILPCI). The aim of the study was to demonstrate that XILPCI is a micron imaging method for gastric structures. Methods The stomachs of 4-, 6- and 12-week-old rats were removed and cleaned. XILPCI has 1000 times greater soft tissue contrast than that of X-ray traditional absorption radiography. The projection images of the rats’ stomachs were recorded by an XILPCI charge coupled device (CCD) at 9 μm image resolution. Results The X-ray in-line phase-contrast images of the different stages of rat gastric specimens clearly showed the gastric architectures and the details of the gastroduodenal region. 3-dimensional stomach anatomical structure images were reconstruction. Conclusion The reconstructed gastric 3D images can clearly display the internal structure of the stomach. XILPCI may be a useful method for medical research in the future. Keywords: Synchrotron radiation phase-contrast imaging, 3-dimensional gastric structure images

Comparison of Electrically Evoked Whole-Nerve Action Potential and Electrically Evoked Auditory Brainstem Response Thresholds in Nucleus CI24R Cochlear Implant Recipients

2002 ◽  
Vol 13 (08) ◽  
pp. 416-427 ◽  
Author(s):  
Marcia J. Hay-McCutcheon ◽  
Carolyn J. Brown ◽  
Kelly Schmidt Clay ◽  
Keely Seyle
Keyword(s):  
Action Potential ◽  
Cochlear Implant ◽  
Auditory Brainstem Response ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
Electrode Arrays ◽  
Direct Stimulation ◽  
Nerve Action ◽  
Brainstem Response ◽  
Response Thresholds

In this study, differences between electrically evoked whole-nerve action potential (EAP) and electrically evoked auditory brainstem response (EABR) measurements within Nucleus CI24R cochlear implant recipients were evaluated. Precurved modiolus-hugging internal electrode arrays, such as the CI24R, are designed to provide more direct stimulation of neural elements of the modiolus. If the electrode array is closer to the modiolus, electrically evoked and behavioral levels might be lower than were previously recorded for the straight electrode array, the CI24M. EAP and EABR growth functions and behavioral levels were obtained for 10 postlingually deafened adults. Results revealed no significant differences between EAP and EABR threshold levels, and these levels were not significantly lower than those obtained using the CI24M.

scholarly journals Variations in Cochlear Size of Cochlear Implant Candidates

2018 ◽  
Vol 23 (02) ◽  
pp. 184-190 ◽  
Author(s):  
Devira Zahara ◽  
Rima Diana Dewi ◽  
Askaroellah Aboet ◽  
Fikri Mirza Putranto ◽  
Netty Delvrita Lubis ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Temporal Bone ◽  
Three Dimensional ◽  
Mathematical Function ◽  
Electrode Arrays ◽  
High Resolution Computed Tomography ◽  
Bone Measurement ◽  
Length Width ◽  
Hrct Temporal Bone ◽  
Half Turn

Introduction The cochlear anatomy varies in each individual, and that has an impact on decisions regarding the insertion of electrodes. The measurement of the cochlear size is the routine examination required to choose the proper cochlear implant (CI) electrodes. Objective To acquire normative data on the size of the cochlea (length, width, height, scala timpani [ST] height, cochlear duct length [CDL]) of CI candidates in Medan, Indonesia. Methods This descriptive study was conducted based on high-resolution computed tomography (HRCT) temporal bone data and on HRCT temporal data manipulated to reconstruct three-dimensional (3D) multiplanar images with OsiriX MD DICOM Viewer version 9.5.1 (Pixmeo SARL, Bernex, Geneva, Switzerland) viewer of 18 patients (36 ears) who were CI candidates in Medan, Indonesia, in order to determine cochlear length (A), cochlear width, cochlear height, ST height and CDL, calculated through a simple mathematical function. Results The average cochlear length (A) was 8.75 mm (standard deviation [SD] = 0.31 mm); the average cochlear width was 6.53 mm (SD = 0.35 mm); the average cochlear height was 3.26 mm (SD = 0.24 mm) and the average ST height at the basal cochlea was 1.00 mm (SD = 0.1 mm); and 0.71 mm (SD = 0.1 mm) at the half turn of cochlea. The average total CDL was 32.45 mm (SD = 1.31 mm; range: 30.01–34.83 mm). Conclusion The cochlear size varies in each individual; therefore, the temporal bone measurement of CI candidates using HRCT is essential: for the selection of suitable implant electrodes; to minimize cochlear damages at the insertion of the electrode arrays; and to maximize the hearing improvements.

scholarly journals Frictional Behavior of Cochlear Electrode Array Is Dictated by Insertion Speed and Impacts Insertion Force

2021 ◽  
Vol 11 (11) ◽  
pp. 5162
Author(s):  
Dana Dohr ◽  
Nicklas Fiedler ◽  
Wolfram Schmidt ◽  
Niels Grabow ◽  
Robert Mlynski ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Cochlear Implant ◽  
Electrode Array ◽  
Mechanical Trauma ◽  
Electrode Arrays ◽  
Friction Behavior ◽  
Insertion Force ◽  
Friction Coefficients ◽  
Electrode Insertion ◽  
The Impact

Background: During cochlear implantation, the electrode array has significant friction with the sensitive endocochlear lining and causes mutual mechanical trauma while the array is being inserted. Both, the impact of insertion speed on electrode friction and the relationship of electrode insertion force and friction have not been adequately investigated to date. Methods: In this study, friction coefficients between a CI electrode array (31.5 mm) and a tissue simulating the endocochlear lining have been acquired, depending on different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s). Additionally, the electrode insertion forces during the placing into a scala tympani model were recorded and correlated with the friction coefficient. Results: It was shown that the friction coefficient reached the lowest value at an insertion speed of 0.1 mm/s (0.24 ± 0.13), a maximum occurred at 1.5 mm/s (0.59 ± 0.12), and dropped again at 2 mm/s (0.45 ± 0.11). Similar patterns were observed for the insertion forces. Consequently, a high correlation coefficient (0.9) was obtained between the insertion forces and friction coefficients. Conclusion: The present study reveals a non-linear increase in electrode array friction, when insertion speed raises and reports a high correlation between friction coefficient and electrode insertion force. This dependence is a relevant future parameter to evaluate and reduce cochlear implant insertion trauma. Significance statement: Here, we demonstrated a dependence between cochlear electrode insertion speed and its friction behavior and a high correlation to insertion force. Our study provides valuable information for the evaluation and prevention of cochlear implant insertion trauma and supports the optimization of cochlear electrode arrays regarding friction characteristics.

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