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Lenham FM, Iball GR. Improving the quality of computed tomography brain images in the presence of cochlear implant induced metal artefacts through the additional use of tissue mimicking materials alongside metal artefact reduction software. Radiography (Lond) 2024; 30:813-820. [PMID: 38513334 DOI: 10.1016/j.radi.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/15/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024]
Abstract
INTRODUCTION Metal artefact reduction software (MAR) can be used to improve Computed Tomography (CT) image quality in the presence of implanted metalwork; however, this software is not effective for superficial metallic structures such as cochlear implants (CI). This study aimed to investigate whether the effectiveness of MAR software could be improved for brain scans with CI present through the use of tissue mimicking materials (TMM) placed exteriorly to the implant. METHODS In this two-part study, a CI was positioned on the surface of water and anthropomorphic phantoms and imaged using a helical CT brain protocol. Three TMM, Superflab, Sure Thermal heat packs, and Bart's Bolus, were utilised and images were acquired to assess the resulting artefact reduction in terms of CT numbers, noise and artefact index (Aind). Changes in CTDIvol were assessed for the anthropomorphic phantom scans. RESULTS In the water phantom, statistically significant reductions in CT number (p = 0.038) and noise (p = 0.033) were observed for Superflab, whilst the heat packs produced similar significant reductions in CT number (p < 0.001) and noise (p = 0.001) for the anthropomorphic phantom images. Aind values were significantly reduced through the use of Superflab (p = 0.009) and the heat packs (p < 0.001). No significant effects were observed for Bart's Bolus. CTDIvol increases of generally less than 5% were observed for scans with TMM in place. CONCLUSION The additional use of TMM alongside MAR software yielded statistically significant reductions in CI induced metal artefacts on both water and anthropomorphic phantom scans with minimal dose increases. IMPLICATIONS FOR PRACTICE The extent of metal artefacts in clinical head scans with CI in place could be significantly reduced through combined use of TMM and MAR software, consequently providing greater diagnostic confidence in the images.
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Affiliation(s)
- F M Lenham
- Department of Medical Physics & Engineering, Old Medical School, Leeds General Infirmary, Leeds, LS1 3EX, UK.
| | - G R Iball
- Department of Medical Physics & Engineering, Old Medical School, Leeds General Infirmary, Leeds, LS1 3EX, UK; Faculty of Health Studies, University of Bradford, Bradford, BD7 1DP, UK.
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Söderqvist S, Sivonen V, Aarnisalo A, Karppi H, Sinkkonen ST, Koivisto J. OPTIMISING THE PARAMETERS OF COCHLEAR IMPLANT IMAGING WITH CONE-BEAM COMPUTED TOMOGRAPHY. RADIATION PROTECTION DOSIMETRY 2023; 199:462-470. [PMID: 36789742 PMCID: PMC10077498 DOI: 10.1093/rpd/ncad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/22/2022] [Accepted: 01/15/2023] [Indexed: 06/18/2023]
Abstract
With computed tomography (CT), the delicate structures of the inner ear may be hard to visualise, which a cochlear implant (CI) electrode array can further complicate. The usefulness of a novel cone-beam CT device in CI recipient's inner ear imaging was evaluated and the exposure parameters were optimised to attain adequate clinical image quality at the lowest effective dose (ED). Six temporal bones were implanted with a Cochlear Slim Straight electrode array and imaged with six different imaging protocols. Contrast-to-noise ratio was calculated for each imaging protocol, and three observers evaluated independently the image quality of each imaging protocol and temporal bone. The overall image quality of the inner ear structures did not differ between the imaging protocols and the most relevant inner ear structures of CI recipient's inner ear can be visualised with a low ED. To visualise the most delicate structures in the inner ear, imaging protocols with higher radiation exposure may be required.
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Affiliation(s)
| | - Ville Sivonen
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Antti Aarnisalo
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | | | - Saku T Sinkkonen
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Tauno Palva Laboratory, Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital, Helsinki, Finland
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
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Karkas A, Boureille P, Laroche N, Vico L, Bergandi F, Marotte H. Imaging of the human cochlea using micro-computed tomography before and after cochlear implantation: comparison with cone-beam computed tomography. Eur Arch Otorhinolaryngol 2023; 280:3131-3140. [PMID: 36604323 DOI: 10.1007/s00405-022-07811-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE Analysis of cochlear structures and postoperative temporal bone (TB) imaging are gaining importance in the evaluation of cochlear implantation (CI°). Our aims were to explore the microarchitecture of human cochlea using micro-computed tomography (μCT), analyze electrode's placement inside cochlea after CI°, and compare pre-/post-implantation μCT scans with cone-beam CT (CBCT) scans of same TBs. METHODS Cadaveric TBs were scanned using μCT and CBCT then underwent CI° using straight electrodes. Thereafter, they underwent again μCT and CBCT-imaging. RESULTS Ten TBs were studied. μCT allowed visualization of scala tympani, scala vestibuli, basilar membrane, osseous spiral lamina, crista fenestrae, and spiral ligament. CBCT showed same structures except spiral ligament and crista fenestrae. After CI°, μCT and CBCT displayed the scalar location and course of electrode array within the cochlea. There were 7 cases of atraumatic electrode insertion and 3 cases of insertion trauma: basilar membrane elevation, electrode foldover with limited migration into scala vestibuli, and electrode kinking with limited migration into scala vestibuli. Insertion trauma was not correlated with cochlea's size or crista's maximal height but with round window membrane diameter. Resolution of μCT was higher than CBCT but electrode artifacts were similar. CONCLUSIONS μCT was accurate in visualizing cochlear structures, and course and scalar position of electrode array inside cochlea with any possible trauma to cochlea or array. CBCT offers a good alternative to μCT in clinical practice for cochlear imaging and evaluation of CI°, with lower radiation and higher resolution than multi-slice CT. Difficulties related to non-traumatic CI° are multifactorial.
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Affiliation(s)
- Alexandre Karkas
- Service Oto-Rhino-Laryngologie, Division of Otology/Neurotology, Hôpital Nord, University Medical Center of Saint-Etienne, CHU Saint-Etienne, 42055, Saint-Etienne, France. .,Laboratory of Biology of Osteo-Articular Tissues, SAINBIOSE Inserm U1059, Saint-Etienne, France. .,Laboratory of Anatomy of Medical School Jacques Lisfranc, Saint-Etienne, France.
| | - Pierre Boureille
- Laboratory of Biology of Osteo-Articular Tissues, SAINBIOSE Inserm U1059, Saint-Etienne, France.,Division of Neuroradiology, University Medical Center of Saint-Etienne, Saint-Etienne, France
| | - Norbert Laroche
- Laboratory of Biology of Osteo-Articular Tissues, SAINBIOSE Inserm U1059, Saint-Etienne, France
| | - Laurence Vico
- Laboratory of Biology of Osteo-Articular Tissues, SAINBIOSE Inserm U1059, Saint-Etienne, France
| | - Florian Bergandi
- Laboratory of Anatomy of Medical School Jacques Lisfranc, Saint-Etienne, France
| | - Hubert Marotte
- Laboratory of Biology of Osteo-Articular Tissues, SAINBIOSE Inserm U1059, Saint-Etienne, France.,Department of Rheumatology, University Medical Center of Saint-Etienne, Saint-Etienne, France
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Visualization of Different Types of Cochlear Implants in Postoperative Cone-Beam CT Imaging. Acad Radiol 2022; 29 Suppl 3:S88-S97. [PMID: 33840600 DOI: 10.1016/j.acra.2021.02.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 02/11/2021] [Accepted: 02/23/2021] [Indexed: 11/20/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate cone-beam computed-tomography (CBCT) images of the temporal bone for radiological delineation, metal artifacts, and accuracy for localization of six different electrode arrays after cochlear device implantation. MATERIALS AND METHODS This retrospective study included 116 patients who underwent CBCT (120kV, 7.1mA) within 24 hours after cochlear device implantation. Exclusion criteria were anatomical abnormalities, and electrode misinsertion. Six different CI electrodes were implanted: Advanced Bionics HiFocus Mid-Scala, Cochlear Contour Advance, Cochlear Slim-Straight, Cochlear Slim-Modiolar, MED-EL Flex 24 and MED-EL Flex 28. Two radiologists rated independently presence of metal artifacts, overall image quality, as well as dedicated visualization of the osseous spiral lamina, inner and outer cochlear wall, single electrode contacts, and electrode position using 5-point-Likert scales. Inter-rater agreement was calculated by using Cohen's kappa and intraclass correlation. RESULTS Of 116 patients, 94 (81.0%; 56.1 ± 16.9 years; age range, 13-86 years; 49 [52.1%] females) were included in the study. Overall image quality was rated good for all electrode models without significant differences (p = 0.061). Depiction of electrode contacts was rated significantly better for Advanced Bionics HiFocus Mid-Scala, Cochlear Slim-Straight, and MED-EL Flex 24 and 28 compared to Cochlear Contour Advance and Slim-Modiolar (p < 0.001). Depiction of the osseous spiral lamina (p = 0.20), inner (p = 0.42) and outer cochlear wall (p = 0.35), metal artifacts (p = 0.18), and electrode position (p = 0.31) did not show significant differences between electrode models. Inter-rater agreement varied from substantial to almost perfect (0.70-0.93). CONCLUSION CBCT provides excellent visualization of all evaluated CI electrode types, in particular electrode arrays with greater spacing between contacts and contact size allow improved radiologic evaluation.
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Burck I, Helal RA, Naguib NNN, Nour-Eldin NEA, Scholtz JE, Martin S, Leinung M, Helbig S, Stöver T, Lehn A, Vogl TJ. Postoperative radiological assessment of the mastoid facial canal in cochlear implant patients in correlation with facial nerve stimulation. Eur Radiol 2021; 32:234-242. [PMID: 34226991 PMCID: PMC8660739 DOI: 10.1007/s00330-021-08128-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/22/2021] [Accepted: 06/09/2021] [Indexed: 11/25/2022]
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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Affiliation(s)
- Iris Burck
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Rania A Helal
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Nagy N N Naguib
- Department of Radiology, AMEOS Clinic Halberstadt, Halberstadt, Sachsen-Anhalt, Germany
- Department of Diagnostic and Interventional Radiology, Alexandria University Hospital, Alexandria University, Alexandria, Egypt
| | - Nour-Eldin A Nour-Eldin
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
- Department of Diagnostic and Interventional Radiology, Cairo University Hospital, Cairo University, Cairo, Egypt
| | - Jan-Erik Scholtz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Simon Martin
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Martin Leinung
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | - Silke Helbig
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | - Timo Stöver
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | - Annette Lehn
- Department of Biostatistics and Mathematical Modeling, University Hospital Frankfurt, Frankfurt, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
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