Improved middle-ear soft-tissue visualization using synchrotron radiation phase-contrast imaging

Elfarnawany, Mai; Rohani, Seyed Alireza; Ghomashchi, Soroush; Allen, Daniel; Zhu, Ning; Agrawal, Sumit; Ladak, Hanif M.

doi:10.1016/j.heares.2017.08.001

Cited by 24 publications

(28 citation statements)

References 43 publications

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“…SR‐PCI was completed using the Bio‐Medical Imaging and Therapy beamline at the Canadian Light Source Inc. in Saskatoon, SK, Canada. This method has been presented in our previous works (Elfarnawany et al ., , b). A schematic diagram of the imaging setup is given in Figure .…”

Section: Methodsmentioning

confidence: 97%

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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Section: Methodsmentioning

confidence: 97%

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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“…All samples were fixed in a 4F1G (4% formaldehyde + 1% glutaraldehyde in phosphate buffer) bath for five days. The samples were then rinsed and dehydrated using an ethanol series as described in our previous works (Rohani et al ., 2016; Elfarnawany et al ., 2017a, b). In all three samples, the ISJ was dissected for imaging.…”

Section: Methodsmentioning

confidence: 99%

“…1). Sample TB01 was used in our previous study (Elfarnawany et al ., 2017a, b) and the ISJ was dissected by cutting the stapes neck and lenticular process of the incus. All samples were then secured in a plastic container and mounted on a piece of wax to avoid movement during imaging.…”

Section: Methodsmentioning

confidence: 99%

“…Similar to our previous works on imaging the cochlea (Elfarnawany et al ., 2017a, b; Rohani et al ., 2018) and the middle ear (Elfarnawany et al ., 2017a, b), all three samples were scanned using the Bio‐Medical Imaging and Therapy (BMIT) 05ID‐2 beamline at the Canadian Light Source Inc. in Saskatoon, SK, Canada. A custom‐built micro‐CT system (Skyscan, Bruker Inc., Kontich, Belgium) was used as a detector with the synchrotron beamline for imaging the ISJ samples.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we have shown synchrotron‐radiation phase‐contrast imaging (SR‐PCI) as a method to provide detailed insight into the complex geometry of the middle‐ear components, including the ISJ (Elfarnawany et al ., 2017a, b). The voxel size of 9 µm in reconstructed images in addition to the high soft‐tissue contrast produced by SR‐PCI has resulted in clear visualisation of the overall ISJ space; however, the ISJ ultrastructure (e.g.…”

Section: Introductionmentioning

confidence: 99%

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High‐resolution imaging of the human incudostapedial joint using synchrotron‐radiation phase‐contrast imaging

Rohani

Allen

Gare

et al. 2020

Journal of Microscopy

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Summary The incudostapedial joint (ISJ) of the middle ear is important for proper transmission of sound energy to the cochlea. Recently, the biomechanics of the ISJ have been investigated using finite‐element (FE) modelling, using simplified geometry. The objective of the present study was to investigate the feasibility of synchrotron‐radiation phase‐contrast imaging (SR‐PCI) in visualising the ISJ ultrastructure. Three human cadaveric ISJs were dissected and scanned using SR‐PCI at 0.9 µm isotropic voxel size. One of the samples was previously scanned at 9 µm voxel size. The images were visually compared and contrast‐to‐noise ratios (CNRs) were calculated (of both bone and soft tissues) for quantitative comparisons. The ISJ ultrastructure as well as adjacent bone and soft tissues were clearly visible in images with a 0.9 µm voxel size. The CNRs of the 0.9 µm images were relatively lower than those of the 9 µm scans, while the ratio of bone to soft tissue CNRs were higher, indicating better discernibility of bone from soft tissue in the 0.9 µm scans. This study was the first known attempt to image the ISJ ultrastructure using an SR‐PCI scanner at submicron voxel size and results suggest that this method was successful. Future studies are needed to optimise the contrast and test the feasibility of imaging the ISJ in situ. Lay Description The human middle ear consists of the eardrum, three small bones (the malleus, incus and stapes) and two joints connecting the bones (the incudostapedial joint and the incudomallear joint). The role of the middle ear is to amplify and transfer sound energy to the cochlea, the end organ of hearing. The incudostapedial joint (ISJ) of the middle ear is a synovial joint which is important for proper transmission of sound energy to the cochlea. Similar to other synovial joints it consists of meniscus, fluid and articulating surfaces. Recently, the biomechanics of the ISJ have been investigated using computational models, using grossly simplified geometry. Synchrotron radiation phase contrast imaging (SR‐PCI) is a high‐resolution imaging technique used to visualise small structures in three dimensions. The objective of the present study was to investigate the feasibility of using SR‐PCI in visualising the ISJ ultrastructure. Three human cadaveric ISJs were dissected and scanned using SR‐PCI at 0.9 µm isotropic voxel size. One of the samples was previously scanned at 9 µm voxel size. The images were both qualitatively and quantitatively compared. This study was the first known attempt to image the ISJ ultrastructure using an SR‐PCI scanner at submicron voxel size and results suggest that this method was successful. Future studies are needed to optimise the contrast and feasibility of imaging the ISJ in situ.

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Deep Learning for Automated Image Segmentation of the Middle Ear: A Scoping Review

Ross,

Tanna,

Lilaonitkul

et al. 2024

Otolaryngol.--head neck surg.

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ObjectiveConvolutional neural networks (CNNs) have revolutionized medical image segmentation in recent years. This scoping review aimed to carry out a comprehensive review of the literature describing automated image segmentation of the middle ear using CNNs from computed tomography (CT) scans.Data SourcesA comprehensive literature search, generated jointly with a medical librarian, was performed on Medline, Embase, Scopus, Web of Science, and Cochrane, using Medical Subject Heading terms and keywords. Databases were searched from inception to July 2023. Reference lists of included papers were also screened.Review MethodsTen studies were included for analysis, which contained a total of 866 scans which were used in model training/testing. Thirteen different architectures were described to perform automated segmentation. The best Dice similarity coefficient (DSC) for the entire ossicular chain was 0.87 using ResNet. The highest DSC for any structure was the incus using 3D‐V‐Net at 0.93. The most difficult structure to segment was the stapes, with the highest DSC of 0.84 using 3D‐V‐Net.ConclusionsNumerous architectures have demonstrated good performance in segmenting the middle ear using CNNs. To overcome some of the difficulties in segmenting the stapes, we recommend the development of an architecture trained on cone beam CTs to provide improved spatial resolution to assist with delineating the smallest ossicle.Implications for PracticeThis has clinical applications for preoperative planning, diagnosis, and simulation.

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Improved middle-ear soft-tissue visualization using synchrotron radiation phase-contrast imaging

Cited by 24 publications

References 43 publications

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

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

High‐resolution imaging of the human incudostapedial joint using synchrotron‐radiation phase‐contrast imaging

Deep Learning for Automated Image Segmentation of the Middle Ear: A Scoping Review

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