Evaluation of cochlear implant electrode scalar position by 3 Tesla magnet resonance imaging

AbstractThe estimation of scalar electrode position is a central point of quality control during the cochlear implant procedure. Ionic radiation is a disadvantage of commonly used radiologic estimation of electrode position. Recent developments in the field of cochlear implant magnets, implant receiver magnet position, and MRI sequence usage allow the postoperative evaluation of inner ear changes after cochlear implantation. The aim of the present study was to evaluate the position of lateral wall and modiolar cochlear implant electrodes using 3 T MRI scanning. In a prospective study, we evaluated 20 patients (10× Med-El Flex 28; 5× HFMS AB and 5× SlimJ AB) with a 3 T MRI and a T2 2D Drive MS sequence (voxel size: 0.3 × 0.3 × 0.9 mm) for the estimation of the intracochlear position of the cochlear implant electrode. In all cases, MRI allowed a determination of the electrode position in relation to the basilar membrane. This observation made the estimation of 19 scala tympani electrode positions and a single case of electrode translocation possible. 3 T MRI scanning allows the estimation of lateral wall and modiolar electrode intracochlear scalar positions.

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High resolution evaluation of various cochlear implant electrodes’ scalar position by 3T MRI

10.21203/rs.3.rs-397570/v1 ◽

2021 ◽

Author(s):

C Riemann ◽

LU Scholtz ◽

HB Gehl ◽

H Sudhoff ◽

I. Todt

Keyword(s):

Cochlear Implant ◽

Basilar Membrane ◽

Single Case ◽

Lateral Wall ◽

Electrode Position ◽

Voxel Size ◽

3T Mri ◽

Recent Developments ◽

A Prospective Study

Abstract Objective: The estimation of scalar electrode position is a central point of quality control during the cochlear implant procedure. Ionic radiation is a disadvantage of commonly used radiologic estimation of electrode position. Recent developments in the field of cochlear implant magnets, implant receiver magnet position, and MRI sequence usage allow the postoperative evaluation of inner ear changes after cochlear implantation.The aim of the present study was to evaluate the position of lateral wall and modiolar cochlear implant electrodes using 3T MRI scanning.Material and Methods: In a prospective study, we evaluated 20 patients (10x Med-El Flex 28; 5x HFMS AB and 5x SlimJ AB) with a 3T MRI and a T2 2D Drive MS sequence (voxel size: 0.3 x 0.3 x 0.9 mm) for the estimation of the intracochlear position of the cochlear implant electrode.Results: In all cases, MRI allowed a determination of the electrode position in relation to the basilar membrane. This observation made the estimation of 19 scala tympani electrode positions and a single case of electrode translocation possible.Conclusion: 3T MRI scanning allows the estimation of lateral wall and modiolar electrode intracochlear scalar positions.

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Magnetic Steering of Robotically Inserted Lateral-wall Cochlear-implant Electrode Arrays Reduces Forces on the Basilar Membrane In Vitro

Otology & Neurotology ◽

10.1097/mao.0000000000003129 ◽

2021 ◽

Vol Publish Ahead of Print ◽

Author(s):

Cameron M. Hendricks ◽

Matt S. Cavilla ◽

David E. Usevitch ◽

Trevor L. Bruns ◽

Katherine E. Riojas ◽

...

Keyword(s):

Cochlear Implant ◽

Basilar Membrane ◽

Lateral Wall ◽

Electrode Arrays ◽

Magnetic Steering

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MRI Pattern of Various Cochlear Implant Electrodes In Vivo

Annals of Otology and Neurotology ◽

10.1055/s-0040-1708796 ◽

2019 ◽

Vol 2 (02) ◽

pp. 51-55

Author(s):

Holger Sudhoff ◽

Conrad Riemann ◽

Hans Björn Gehl ◽

Ingo Todt

Keyword(s):

Cochlear Implant ◽

Spin Echo ◽

Lateral Wall ◽

In Vivo Evaluation ◽

Insertion Depth ◽

Implant Positioning ◽

Electrode Length ◽

Recent Developments ◽

Magnetic Resonance Imaging Mri

Abstract Introduction Recent developments regarding cochlear implant magnets (e.g., a bipolar diametral magnet) and refined surgical technique (e.g., implant positioning) have made a significant impact on the relation between a cochlear implant and magnetic resonance imaging (MRI). MRI scanning has changed from a contraindication to a diagnostic tool. For the first time, a pain-free in vivo evaluation of the cochlea’s fluid state, following the insertion of an electrode, has become possible via MRI scanning. The aim of this study was to evaluate various cochlear implant electrodes’ MRI-specific patterns. Materials and Methods In a retrospective study, we evaluated the MRI pattern of casting iron (CI) electrodes in a 3T T2 turbo spin echo (TSE) sequence after a surgery with Medel Flex 28, Flex 24, AB HFMS, and MRI at 1.5 T T2 TSE with the Oticon EVO array. Results A generally different axial MRI pattern between the “lateral wall” electrodes and the “modiolar” electrodes at the basal turn could be observed. A difference in terms of electrode length/insertion depth could not be found at the present scan resolution. Electrode contacts have an impact on the MRI signal-diminishing pattern. Conclusion At T2 sequences, an electrode design-specific MRI pattern can be observed.

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Effect of Scala Tympani Height on Insertion Depth of Straight Cochlear Implant Electrodes

Otolaryngology ◽

10.1177/0194599820904941 ◽

2020 ◽

Vol 162 (5) ◽

pp. 718-724 ◽

Cited By ~ 1

Author(s):

William G. Morrel ◽

Jourdan T. Holder ◽

Benoit M. Dawant ◽

Jack H. Noble ◽

Robert F. Labadie

Keyword(s):

Cochlear Implant ◽

Retrospective Review ◽

Basilar Membrane ◽

Lateral Wall ◽

Scala Tympani ◽

Tertiary Referral ◽

Insertion Depth ◽

Tertiary Referral Center ◽

Relationship Of ◽

The Relationship

Objective Studies suggest lateral wall (LW) scala tympani (ST) height decreases apically, which may limit insertion depth. No studies have investigated the relationship of LW ST height with translocation rate or location. Study Design Retrospective review. Setting Cochlear implant program at tertiary referral center. Subjects and Methods LW ST height was measured in preoperative images for patients with straight electrodes. Scalar location, angle of insertion depth (AID), and translocation depth were measured in postoperative images. Audiologic outcomes were tracked. Results In total, 177 ears were identified with 39 translocations (22%). Median AID was 443° (interquartile range [IQR], 367°-550°). Audiologic outcomes (126 ears) showed a small, significant correlation between consonant-nucleus-consonant (CNC) word score and AID ( r = 0.20, P = .027), although correlation was insignificant if translocation occurred ( r = 0.11, P = .553). Translocation did not affect CNC score ( P = .335). AID was higher for translocated electrodes (503° vs 445°, P = .004). Median translocation depth was 381° (IQR, 222°-399°). Median depth at which a 0.5-mm electrode would not fit within 0.1 mm of LW was 585° (IQR, 405°-585°). Median depth at which a 0.5-mm electrode would displace the basilar membrane by ≥0.1 mm was 585° (IQR, 518°-765°); this was defined as predicted translocation depth (PTD). Translocation rate was 39% for insertions deeper than PTD and 14% for insertions shallower than PTD ( P = .008). Conclusion AID and CNC are directly correlated for straight electrodes when not translocated. Translocations generally occur around 380° and are more common with deeper insertions due to decreasing LW ST height. Risk of translocation increases significantly after 580°.

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High-resolution microscopy of twin boundaries in gold

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126202 ◽

1987 ◽

Vol 45 ◽

pp. 260-261

Author(s):

William Krakow ◽

David A. Smith

Keyword(s):

High Resolution ◽

Specimen Preparation ◽

Gold Films ◽

Boundary Area ◽

Transmission Electron ◽

Recent Developments ◽

Tilt Boundaries ◽

High Resolution Microscopy ◽

Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

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Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18041768 ◽

2021 ◽

Vol 18 (4) ◽

pp. 1768

Author(s):

Hernâni Marques ◽

Pedro Cruz-Vicente ◽

Tiago Rosado ◽

Mário Barroso ◽

Luís A. Passarinha ◽

...

Keyword(s):

Tobacco Smoke ◽

Solid Phase ◽

Smoke Exposure ◽

Tobacco Smoke Exposure ◽

World Health ◽

Second Hand Smoke ◽

Tobacco Exposure ◽

Wide Range ◽

Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

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Revisiting Electrochemical Biosensing in the 21st Century Society for Inflammatory Cytokines Involved in Autoimmune, Neurodegenerative, Cardiac, Viral and Cancer Diseases

Sensors ◽

10.3390/s21010189 ◽

2020 ◽

Vol 21 (1) ◽

pp. 189

Author(s):

Susana Campuzano ◽

Paloma Yáñez-Sedeño ◽

José Manuel Pingarrón

Keyword(s):

Point Of Care ◽

Low Cost ◽

Accurate Determination ◽

Test Time ◽

Electrochemical Biosensing ◽

Recent Developments ◽

Inflammatory Processes ◽

Human Skills ◽

Cancer Diseases

The multifaceted key roles of cytokines in immunity and inflammatory processes have led to a high clinical interest for the determination of these biomolecules to be used as a tool in the diagnosis, prognosis, monitoring and treatment of several diseases of great current relevance (autoimmune, neurodegenerative, cardiac, viral and cancer diseases, hypercholesterolemia and diabetes). Therefore, the rapid and accurate determination of cytokine biomarkers in body fluids, cells and tissues has attracted considerable attention. However, many currently available techniques used for this purpose, although sensitive and selective, require expensive equipment and advanced human skills and do not meet the demands of today’s clinic in terms of test time, simplicity and point-of-care applicability. In the course of ongoing pursuit of new analytical methodologies, electrochemical biosensing is steadily gaining ground as a strategy suitable to develop simple, low-cost methods, with the ability for multiplexed and multiomics determinations in a short time and requiring a small amount of sample. This review article puts forward electrochemical biosensing methods reported in the last five years for the determination of cytokines, summarizes recent developments and trends through a comprehensive discussion of selected strategies, and highlights the challenges to solve in this field. Considering the key role demonstrated in the last years by different materials (with nano or micrometric size and with or without magnetic properties), in the design of analytical performance-enhanced electrochemical biosensing strategies, special attention is paid to the methods exploiting these approaches.

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Postoperative radiological assessment of the mastoid facial canal in cochlear implant patients in correlation with facial nerve stimulation

European Radiology ◽

10.1007/s00330-021-08128-w ◽

2021 ◽

Author(s):

Iris Burck ◽

Rania A. Helal ◽

Nagy N. N. Naguib ◽

Nour-Eldin A. Nour-Eldin ◽

Jan-Erik Scholtz ◽

...

Keyword(s):

Facial Nerve ◽

Cochlear Implant ◽

Nerve Stimulation ◽

Lateral Wall ◽

Facial Canal ◽

Chorda Tympani ◽

Radiological Assessment ◽

Canal Diameter ◽

History Of ◽

Facial Nerve Stimulation

Abstract Objectives To correlate the radiological assessment of the mastoid facial canal in postoperative cochlear implant (CI) cone-beam CT (CBCT) and other possible contributing clinical or implant-related factors with postoperative facial nerve stimulation (FNS) occurrence. Methods Two experienced radiologists evaluated retrospectively 215 postoperative post-CI CBCT examinations. The mastoid facial canal diameter, wall thickness, distance between the electrode cable and mastoid facial canal, and facial-chorda tympani angle were assessed. Additionally, the intracochlear position and the insertion angle and depth of electrodes were evaluated. Clinical data were analyzed for postoperative FNS within 1.5-year follow-up, CI type, onset, and causes for hearing loss such as otosclerosis, meningitis, and history of previous ear surgeries. Postoperative FNS was correlated with the measurements and clinical data using logistic regression. Results Within the study population (mean age: 56 ± 18 years), ten patients presented with FNS. The correlations between FNS and facial canal diameter (p = 0.09), wall thickness (p = 0.27), distance to CI cable (p = 0.44), and angle with chorda tympani (p = 0.75) were statistically non-significant. There were statistical significances for previous history of meningitis/encephalitis (p = 0.001), extracochlear-electrode-contacts (p = 0.002), scala-vestibuli position (p = 0.02), younger patients’ age (p = 0.03), lateral-wall-electrode type (p = 0.04), and early/childhood onset hearing loss (p = 0.04). Histories of meningitis/encephalitis and extracochlear-electrode-contacts were included in the first two steps of the multivariate logistic regression. Conclusion The mastoid-facial canal radiological assessment and the positional relationship with the CI electrode provide no predictor of postoperative FNS. Histories of meningitis/encephalitis and extracochlear-electrode-contacts are important risk factors. Key Points • Post-operative radiological assessment of the mastoid facial canal and the positional relationship with the CI electrode provide no predictor of post-cochlear implant facial nerve stimulation. • Radiological detection of extracochlear electrode contacts and the previous clinical history of meningitis/encephalitis are two important risk factors for postoperative facial nerve stimulation in cochlear implant patients. • The presence of scala vestibuli electrode insertion as well as the lateral wall electrode type, the younger patient’s age, and early onset of SNHL can play important role in the prediction of post-cochlear implant facial nerve stimulation.

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Developments in mycotoxin analysis: an update for 2015-2016

World Mycotoxin Journal ◽

10.3920/wmj2016.2138 ◽

2017 ◽

Vol 10 (1) ◽

pp. 5-29 ◽

Cited By ~ 47

Author(s):

F. Berthiller ◽

C. Brera ◽

M.H. Iha ◽

R. Krska ◽

V.M.T. Lattanzio ◽

...

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Critical Review ◽

Analytical Methods ◽

Ergot Alkaloids ◽

Sampling Strategies ◽

Liquid Chromatography Mass Spectrometry ◽

Recent Developments ◽

Mycotoxin Analysis

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.

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