Evaluation of Cochlear Duct Length Computations Using Synchrotron Radiation Phase-Contrast Imaging

Koch, Robert W.; Elfarnawany, Mai; Zhu, Ning; Ladak, Hanif M.; Agrawal, Sumit

doi:10.1097/mao.0000000000001410

Cited by 60 publications

(74 citation statements)

References 24 publications

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“…The SR-PCI technique used was recently described by Elfarnawany et al (2017) and Koch et al (2017). A total of 26 fresh-frozen, then fixed, adult cadaveric temporal bones were used in this study.…”

Section: Methodsmentioning

confidence: 99%

Three‐dimensional imaging of the human internal acoustic canal and arachnoid cistern: a synchrotron study with clinical implications

Mei

Schart-Morén

et al. 2018

Journal of Anatomy

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A thorough knowledge of the gross and micro‐anatomy of the human internal acoustic canal (IAC) is essential in vestibular schwannoma removal, cochlear implantation (CI) surgery, vestibular nerve section, and decompression procedures. Here, we analyzed the acoustic‐facial cistern of the human IAC, including nerves and anastomoses using synchrotron phase contrast imaging (SR‐PCI). A total of 26 fresh human temporal bones underwent SR‐PCI. Data were processed using volume‐rendering software to create three‐dimensional (3D) reconstructions allowing soft tissue analyses, orthogonal sectioning, and cropping. A scalar opacity mapping tool was used to enhance tissue surface borders, and anatomical structures were color‐labeled for improved 3D comprehension of the soft tissues. SR‐PCI reproduced, for the first time, the variable 3D anatomy of the human IAC, including cranial nerve complexes, anastomoses, and arachnoid membrane invagination (acoustic‐facial cistern; an extension of the cerebellopontine cistern) in unprocessed, un‐decalcified specimens. An unrecognized system of arachnoid pillars and trabeculae was found to extend between the arachnoid and cranial nerves. We confirmed earlier findings that intra‐meatal vestibular schwannoma may grow unseparated from adjacent nerves without duplication of the arachnoid layers. The arachnoid pillars may support and stabilize cranial nerves in the IAC and could also play a role in local fluid hydrodynamics.

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Section: Methodsmentioning

confidence: 99%

Three‐dimensional imaging of the human internal acoustic canal and arachnoid cistern: a synchrotron study with clinical implications

Mei

Schart-Morén

et al. 2018

Journal of Anatomy

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Section: Introductionmentioning

confidence: 99%

“…Using this equation, Koch et al . () showed that an electrode array placement mismatch of only 6 mm can result in a frequency mismatch of 1100 Hz in the basal region and 400 Hz in the apical region of the cochlea. Another study carried out by Fu et al .…”

Section: Introductionmentioning

confidence: 99%

“…The location of the CI electrode array is also important for postoperative frequency mapping, whereby the inserted array is programmed to match the tonotopic arrangement of the cochlea (Noble et al, , 2016. This programming is supplemented by the Greenwood equation (Greenwood, 1990;Koch et al, 2017). Using this equation, Koch et al (2017) showed that an electrode array placement mismatch of only 6 mm can result in a frequency mismatch of 1100 Hz in the basal region and 400 Hz in the apical region of the cochlea.…”

Section: Introductionmentioning

confidence: 99%

“…This programming is supplemented by the Greenwood equation (Greenwood, 1990;Koch et al, 2017). Using this equation, Koch et al (2017) showed that an electrode array placement mismatch of only 6 mm can result in a frequency mismatch of 1100 Hz in the basal region and 400 Hz in the apical region of the cochlea. Another study carried out by Fu et al (2002) showed that a minor shift of 2-4 mm in electrode array placement affected patients' rehabilitation times.…”

Section: Introductionmentioning

confidence: 99%

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Effects of object‐to‐detector distance and beam energy on synchrotron radiation phase‐contrast imaging of implanted cochleae

Rohani

Iyaniwura

Zhu

et al. 2018

Journal of Microscopy

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Summary Objectives To demonstrate that synchrotron radiation phase‐contrast imaging (SR‐PCI) can be used to visualize the intrascalar structures in implanted human cochleae and to find the optimal combination of the parameters object‐to‐detector distance (ODD) and beam energy (E) for visualization. Materials and Methods Three cadaveric implanted human temporal bones underwent SR‐PCI with varying combinations of parameters ODD (3, 2 and 1 m) and E (47, 60 and 72 keV). All images were then reconstructed to a three‐dimensional (3D) stack of slices. The acquired 3D images were compared using contrast‐to‐noise ratios (CNRs) of the basilar membrane (CNRitalicBM) and the electrode array (CNRE) and the standard deviation of the beam streaks (σS). Postprocessing calculations were performed using Matlab (Version 2017b, MathWorks Inc., Natick, MA, U.S.A.) with a standard significance level p < 0.05 to determine the most optimal combination of parameters. Results SR‐PCI with computed tomography reconstruction provided good visualization of the anatomical features of the implanted cochleae, specifically the exact location of the electrode with respect to the BM. A single‐factor ANOVA revealed a significant difference of variance for both CNRE and CNRBM, but failed to show significance for σS. A two‐sample t‐test failed to show any significant difference between CNRE columns of (3 m, 72 keV) and (2 m, 60 keV). The CNRBM was significantly different only at two pairs of columns, when (1 m, 72 keV) was compared against (2 m, 72 keV) and (3 m, 72 keV). Conclusions The results of this study show that SR‐PCI is a viable method to visualize implanted human cochleae. SR‐PCI is less invasive, less labour intensive and is associated with a much lower acquisition time compared to other methods for postimplantation imaging in humans, such as histological sectioning. We found that the optimal combination of E and ODD parameters was 72 keV and 2 m, respectively. These parameters resulted in high‐contrast images of the electrode as well as all internal structures of the cochleae. Lay Description Cochlear implants (CI) are currently the preferred method of treatment for hearing loss. Cochlear implantation surgery involves placement of a metallic, wire‐shaped electrode inside the cochlea, the main organ of the human hearing system. Knowledge of the exact location of the electrode after implantation is beneficial in improving the extent of restored hearing. Common clinical imaging modalities such as computed‐tomography (CT) are not ideal for providing such information, due to lack of resolution and streaking caused by the metallic electrode. Recent studies have developed algorithms to extract the electrode location from clinical computed‐tomography images and have been validated using histology or micro computed‐tomography (micro‐CT). Synchrotron radiation phase contrast imaging (SR‐PCI) is a high‐resolution imaging technique used to visualize small structures in three dimensions. Recently, SR‐PCI has been shown to be an alternative to histolog...

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Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

et al. 2021

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Objectives To determine the cochlea's average size in humans and evaluate the relationships between certain covariates and cochlear size. Methods A systematic search on articles on cochlear size and published in English was conducted using Cochrane, PubMed, Web of Science, and Scopus databases up to September 15, 2020. Data were pooled using random‐effects with three models. The effect of demographic, clinical, and measurement‐related parameters was specifically analyzed. Meta‐regression and subgroup analyses were conducted. The overall effect estimation was made for outcomes. Results The meta‐analysis included 4,708 cochleae from 56 studies. The overall length of the organ of Corti was 32.94 mm (95% confidence interval [CI]: 32.51–33.38). The first and second models revealed that age, gender, country, continent, measurement method (direct, indirect), measured structure (“A” value, cochlear lateral wall), origin (in vivo, in vitro), and type (histology specimens, plastic casts, imaging) of the cochlear material did not affect the cochlear size. However, study populations (general population, patients with a cochlear implant, and patients with congenital sensorineural hearing loss [CSNHL]) were found to affect the outcomes. Compared to the other populations, patients with CSNHL had shorter cochleae. Therefore, we developed a third model and found that the general population and patients with cochlear implants did not differ in cochlear size. Conclusion This meta‐analysis investigated the factors that could affect the cochlear size and found that patients with CSNHL had significantly shorter cochleae, whereas other covariates had no significant effect. Laryngoscope, 132:188–197, 2022

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Evaluation of Cochlear Duct Length Computations Using Synchrotron Radiation Phase-Contrast Imaging

Cited by 60 publications

References 24 publications

Three‐dimensional imaging of the human internal acoustic canal and arachnoid cistern: a synchrotron study with clinical implications

Three‐dimensional imaging of the human internal acoustic canal and arachnoid cistern: a synchrotron study with clinical implications

Effects of object‐to‐detector distance and beam energy on synchrotron radiation phase‐contrast imaging of implanted cochleae

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

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