Publications by authors named "Sumit Agrawal"

112 Publications

Stimulation of dorsal hippocampal histaminergic transmission mitigates the expression of ethanol withdrawal-induced despair in mice.

Alcohol 2021 Jul 3. Epub 2021 Jul 3.

Department of Pharmacology, Institute of Pharmaceutical Sciences, Guru Ghasidas Vishwavidyalaya (A Central University), Koni, Bilaspur, Chhattisgarh, India. Electronic address:

Garnered literature points towards the role of the dorsal hippocampus (CA1) in ethanol withdrawal-induced responses, wherein a strong presence of the histaminergic system is also reported. Therefore, the present study investigated the effect of an enhanced CA1 histaminergic transmission on the expression of chronic ethanol withdrawal-induced despair in mice on tail suspension test (TST). The results revealed that mice who were on an ethanol-fed diet (5.96%, v/v) for 8 days, exhibited maximum immobility time on TST, and decreased locomotion at 24 h post ethanol withdrawal (10 day), indicating ethanol withdrawal-induced despair. Enhancement of CA1 histaminergic activity achieved by the treatment of intra-CA1 microinjection of histaminergic agents like histamine (0.1, 10 μg/mouse, bilateral), histamine precursor, L-histidine (1, 10 μg/mouse, bilateral), histamine neuronal releaser/H receptor antagonist, thioperamide (2, 10 μg/mouse, bilateral), histamine H receptor agonist, FMPH (2, 6.5 μg/mouse, bilateral), or H receptor agonist amthamine (0.1, 0.5 μg/mouse, bilateral) to ethanol withdrawn mice, 10 min before 24 h post-ethanol withdrawal time point significantly alleviated the expression of ethanol withdrawal-induced despair in mice on TST. On the other hand, only the pre-treatment of histamine H receptor agonist, FMPH (2, 6.5 μg/mouse, intra-CA1 bilateral) reversed the reduction in locomotor activity induced in ethanol withdrawn mice, wherein other employed histaminergic agents were devoid of any effect on this behavior. Therefore, our findings indicate that an enhanced CA1 histaminergic transmission probably via stimulation of CA1 postsynaptic histamine H or H receptor could preclude the behavioral despair, whilst H stimulation affects motor deficit expressed after ethanol withdrawal.
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http://dx.doi.org/10.1016/j.alcohol.2021.06.002DOI Listing
July 2021

Quality Indicators for the Diagnosis and Management of Menière's Disease.

Otol Neurotol 2021 Jun 4. Epub 2021 Jun 4.

Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Toronto Department of Otolaryngology-Head and Neck Surgery, Western University, London Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, McMaster University, Hamilton, Ontario Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Calgary, Calgary, Alberta Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia Department of Otolaryngology-Head and Neck Surgery, The University of Ottawa and The Ottawa Hospital, Ottawa, Ontario, Canada.

Objective: Menière's disease (MD) is a clinical disorder that often provides challenges in diagnosis and management. High-quality evidence to guide care providers is sparse, which can result in significant practice variations. Quality indicators (QIs) are one method that can be used to standardize and measure accepted care practices to improve healthcare quality and patient outcomes. Here, we developed practical, high-yield QIs that serve to measure and inform the quality of care provided to patients with MD.

Study Design: Modified RAND Corporation University of California, Los Angeles appropriateness methodology for QI development.

Setting: Multicenter nine-member expert panel.

Patients: NA.

Interventions: NA.

Main Outcome Measure: Final QIs deemed appropriate measures of quality care with agreement by the expert panel.

Results: Twenty-seven candidate indicators were identified after literature review. After the first round of evaluations, the panel agreed on three candidate indicators as appropriate QIs. A subsequent expert panel meeting provided a platform to discuss disagreements. Two agreed-upon QIs were revised during this discussion before final evaluations. The expert panel ultimately agreed upon five QIs as appropriate measures of high-quality care after completing final evaluations and reviewing updated literature. The five quality indicators measure audiometric documentation, minimization of electrocochleography, use of intratympanic dexamethasone, use of intratympanic gentamycin, and rate of labyrinthectomy/vestibular neurectomy in refractory MD patient.

Conclusions: This study proposes five QIs that cover key aspects of care for MD, such as accurate diagnosis and management options including initial destructive therapies. These QIs can serve multiple purposes, the most important of which is to galvanize quality improvement initiatives.
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http://dx.doi.org/10.1097/MAO.0000000000003206DOI Listing
June 2021

A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System: Is Meniere's Disease Caused by an Acute Endolymph Backflow?

Front Surg 2021 31;8:662530. Epub 2021 May 31.

Department of Surgical Sciences, Section of Otolaryngology and Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden.

The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (IKI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K-intoxication theory.
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http://dx.doi.org/10.3389/fsurg.2021.662530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8200827PMC
May 2021

Three-Dimensional Modeling and Measurement of the Human Cochlear Hook Region: Considerations for Tonotopic Mapping.

Otol Neurotol 2021 07;42(6):e658-e665

School of Biomedical Engineering, Western University, London, Ontario, Canada.

Hypothesis: Measuring the length of the basilar membrane (BM) in the cochlear hook region will result in improved accuracy of cochlear duct length (CDL) measurements.

Background: Cochlear implant pitch mapping is generally performed in a patient independent approach, which has been shown to result in place-pitch mismatches. In order to customize cochlear implant pitch maps, accurate CDL measurements must be obtained. CDL measurements generally begin at the center of the round window (RW) and ignore the basal-most portion of the BM in the hook region. Measuring the size and morphology of the BM in the hook region can improve CDL measurements and our understanding of cochlear tonotopy.

Methods: Ten cadaveric human cochleae underwent synchrotron radiation phase-contrast imaging. The length of the BM through the hook region and CDL were measured. Two different CDL measurements were obtained for each sample, with starting points at the center of the RW (CDLRW) and the basal-most tip of the BM (CDLHR). Regression analysis was performed to relate CDLRW to CDLHR. A three-dimensional polynomial model was determined to describe the average BM hook region morphology.

Results: The mean CDLRW value was 33.03 ± 1.62 mm, and the mean CDLHR value was 34.68 ± 1.72 mm. The following relationship was determined between CDLRW and CDLHR: CDLHR  = 1.06(CDLRW)-0.26 (R2  = 0.99).

Conclusion: The length and morphology of the hook region was determined. Current measurements underestimate CDL in the hook region and can be corrected using the results herein.
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http://dx.doi.org/10.1097/MAO.0000000000003065DOI Listing
July 2021

Comprehensive metrics for evaluating surgical microscope use during tympanostomy tube placement.

Int J Comput Assist Radiol Surg 2021 Jun 4. Epub 2021 Jun 4.

Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada.

Purpose: Learning to use a surgical microscope is a fundamental step in otolaryngology training; however, there is currently no objective method to teach or assess this skill. Tympanostomy tube placement is a common otologic procedure that requires skilled use of a surgical microscope. This study was designed to (1) implement metrics capable of evaluating microscope use and (2) establish construct validity.

Study Design: This was a prospective cohort study.

Methods: Eight otolaryngology trainees and three otolaryngology experts were asked to use a microscope to insert a tympanostomy tube into a cadaveric myringotomy in a standardized setting. Microscope movements were tracked in a three-dimensional space, and tracking metrics were applied to the data. The procedure was video-recorded and then analyzed by blinded experts using operational metrics. Results from both groups were compared, and discriminatory metrics were determined.

Results: The following tracking metrics were identified as discriminatory between the trainee and expert groups: total completion time, operation time, still time, and jitter (movement perturbation). Many operational metrics were found to be discriminatory between the two groups, including several positioning metrics, optical metrics, and procedural metrics.

Conclusions: Performance metrics were implemented, and construct validity was established for a subset of the proposed metrics by discriminating between expert and novice participants. These discriminatory metrics could form the basis of an automated system for providing feedback to residents during training while using a myringotomy surgical simulator. Additionally, these metrics may be useful in guiding a standardized teaching and evaluation methodology for training in the use of surgical microscopes.
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http://dx.doi.org/10.1007/s11548-021-02428-8DOI Listing
June 2021

Micro-CT of the human ossicular chain: Statistical shape modeling and implications for otologic surgery.

J Anat 2021 May 31. Epub 2021 May 31.

Department of Otolaryngology-Head and Neck Surgery, Western University, London, Canada.

The ossicular chain is a middle ear structure consisting of the small incus, malleus and stapes bones, which transmit tympanic membrane vibrations caused by sound to the inner ear. Despite being shown to be highly variable in shape, there are very few morphological studies of the ossicles. The objective of this study was to use a large sample of cadaveric ossicles to create a set of three-dimensional models and study their statistical variance. Thirty-three cadaveric temporal bone samples were scanned using micro-computed tomography (μCT) and segmented. Statistical shape models (SSMs) were then made for each ossicle to demonstrate the divergence of morphological features. Results revealed that ossicles were most likely to vary in overall size, but that more specific feature variability was found at the manubrium of the malleus, the long process and lenticular process of the incus, and the crura and footplate of the stapes. By analyzing samples as whole ossicular chains, it was revealed that when fixed at the malleus, changes along the chain resulted in a wide variety of final stapes positions. This is the first known study to create high-quality, three-dimensional SSMs of the human ossicles. This information can be used to guide otological surgical training and planning, inform ossicular prosthesis development, and assist with other ossicular studies and applications by improving automated segmentation algorithms. All models have been made publicly available.
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http://dx.doi.org/10.1111/joa.13457DOI Listing
May 2021

Quality Indicators for the Diagnosis and Management of Sudden Sensorineural Hearing Loss.

Otol Neurotol 2021 May 26. Epub 2021 May 26.

Department of Otolaryngology-Head and Neck Surgery, University of Toronto Faculty of Medicine, University of Toronto, Toronto Department of Otolaryngology-Head and Neck Surgery, Western University, London Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, McMaster University, Hamilton, Ontario Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Calgary, Calgary, Alberta Division of Otolaryngology-Head and Neck Surgery Department of Surgery, University of British Columbia, Vancouver, British Columbia Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia Department of Otolaryngology-Head and Neck Surgery, The University of Ottawa and The Ottawa Hospital, Ottawa, Ontario, Canada.

Objective: Sudden sensorineural hearing loss (SSNHL) is an ideal entity for quality indicator (QI) development, providing treatment challenges resulting in variable or substandard care. The American Academy of Otolaryngology-Head and Neck Surgery recently updated their SSNHL guidelines. With SSNHL demonstrating a large burden of illness, this study sought to leverage the updated guidelines and develop QIs that support quality improvement initiatives at an individual, institutional, and systems level.

Methods: Candidate indicators (CIs) were extracted from high-quality SSNHL guidelines that were evaluated using the Appraisal of Guidelines for Research and Evaluation II tool. Each CI and its supporting evidence were summarized and reviewed by a nine-member expert panel based on validity, reliability, and feasibility of measurement. Final QIs were selected from CIs using the modified RAND Corporation-University of California, Los Angeles appropriateness methodology.

Results: Fifteen CIs were identified after literature review. After the first round of evaluations, the panel agreed on 11 candidate indicators as appropriate QIs with 2 additional CIs suggested for consideration. An expert panel meeting provided a platform to discuss areas of disagreement before final evaluations. The expert panel subsequently agreed upon 11 final QIs as appropriate measures of high-quality care for SSNHL.

Conclusion: The 11 proposed QIs from this study are supported by evidence and expert consensus, facilitating measurement across a wide breadth of quality domains. With the recently updated SSNHL guidelines, and a greater focus on quality improvement opportunities, these QIs may be used by healthcare providers for targeted quality improvement initiatives.
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http://dx.doi.org/10.1097/MAO.0000000000003205DOI Listing
May 2021

An Approach for Individualized Cochlear Frequency Mapping Determined from 3D Synchrotron Radiation Phase-Contrast Imaging.

IEEE Trans Biomed Eng 2021 May 13;PP. Epub 2021 May 13.

Objective: Cochlear implants are traditionally programmed to stimulate according to a generalized frequency map, where individual anatomic variability is not considered when selecting the centre frequency of stimulation of each implant electrode. However, high variability in cochlear size and spatial frequency distributions exist among individuals. Generalized cochlear implant frequency maps can result in large pitch perception errors and reduced hearing outcomes for cochlear implant recipients. The objective of this work was to develop an individualized frequency mapping technique for the human cochlea to allow for patient-specific cochlear implant stimulation.

Methods: Ten cadaveric human cochleae were scanned using synchrotron radiation phase-contrast imaging (SR-PCI) combined with computed tomography (CT). For each cochlea, ground truth angle-frequency measurements were obtained in three-dimensions using the SR-PCI CT data. Using an approach designed to minimize perceptual error in frequency estimation, an individualized frequency function was determined to relate angular depth to frequency within the cochlea.

Results: The individualized frequency mapping function significantly reduced pitch errors in comparison to the current gold standard generalized approach.

Conclusion And Significance: This paper presents for the first time a cochlear frequency map which can be individualized using only the angular length of cochleae. This approach can be applied in the clinical setting and has the potential to revolutionize cochlear implant programming for patients worldwide.
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http://dx.doi.org/10.1109/TBME.2021.3080116DOI Listing
May 2021

Arthroscopic Biceps Tenodesis by Bicortical Drilling Technique.

Arthrosc Tech 2021 Apr 2;10(4):e941-e948. Epub 2021 Mar 2.

Department of Orthopaedics, Faculty of Medicine, Thammasat University Hospital, Pathumthani, Thailand.

Pain arising from the long head of biceps tendon can cause significant disability of the shoulder. In young and physically demanding patients, biceps tenodesis is advised, in which the biceps tendon is cut from the native origin and fixed distally. Many methods have been proposed for this. This Technical Note describes arthroscopic biceps tenodesis in the bicipital groove by a bicortical drilling technique. The far cortex is breached only once by a guide wire, and the reamers do not breach the far cortex. The tendon is fixed in the new position using a PopLok anchor. This technique is safe and easy to perform but presents a learning curve.
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http://dx.doi.org/10.1016/j.eats.2020.11.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084844PMC
April 2021

Simultaneous Denoising and Localization Network for Photoacoustic Target Localization.

IEEE Trans Med Imaging 2021 May 3;PP. Epub 2021 May 3.

A significant research problem of recent interest is the localization of targets like vessels, surgical needles, and tumors in photoacoustic (PA) images.To achieve accurate localization, a high photoacoustic signal-to-noise ratio (SNR) is required. However, this is not guaranteed for deep targets, as optical scattering causes an exponential decay in optical fluence with respect to tissue depth. To address this, we develop a novel deep learning method designed to explicitly exhibit robustness to noise present in photoacoustic radio-frequency (RF) data. More precisely, we describe and evaluate a deep neural network architecture consisting of a shared encoder and two parallel decoders. One decoder extracts the target coordinates from the input RF data while the other boosts the SNR and estimates clean RF data. The joint optimization of the shared encoder and dual decoders lends significant noise robustness to the features extracted by the encoder, which in turn enables the network to contain detailed information about deep targets that may be obscured by noise. Additional custom layers and newly proposed regularizers in the training loss function (designed based on observed RF data signal and noise behavior) serve to increase the SNR in the cleaned RF output and improve model performance. To account for depth-dependent strong optical scattering, our network was trained with simulated photoacoustic datasets of targets embedded at different depths inside tissue media of different scattering levels. The network trained on this novel dataset accurately locates targets in experimental PA data that is clinically relevant with respect to the localization of vessels, needles, or brachytherapy seeds. We verify the merits of the proposed architecture by outperforming the state of the art on both simulated and experimental datasets.
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http://dx.doi.org/10.1109/TMI.2021.3077187DOI Listing
May 2021

Vestibular Organ and Cochlear Implantation-A Synchrotron and Micro-CT Study.

Front Neurol 2021 7;12:663722. Epub 2021 Apr 7.

Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada.

Reports vary on the incidence of vestibular dysfunction and dizziness in patients following cochlear implantation (CI). Disequilibrium may be caused by surgery at the cochlear base, leading to functional disturbances of the vestibular receptors and endolymphatic duct system (EDS) which are located nearby. Here, we analyzed the three-dimensional (3D) anatomy of this region, aiming to optimize surgical approaches to limit damage to the vestibular organ. A total of 22 fresh-frozen human temporal bones underwent synchrotron radiation phase-contrast imaging (SR-PCI). One temporal bone underwent micro-computed tomography (micro-CT) after fixation and staining with Lugol's iodine solution (IKI) to increase tissue contrast. We used volume-rendering software to create 3D reconstructions and tissue segmentation that allowed precise assessment of anatomical relationships and topography. Macerated human ears belonging to the Uppsala collection were also used. Drilling and insertion of CI electrodes was performed with metric analyses of different trajectories. SR-PCI and micro-CT imaging demonstrated the complex 3D anatomy of the basal region of the human cochlea, vestibular apparatus, and EDS. Drilling of a cochleostomy may disturb vestibular organ function by injuring the endolymphatic space and disrupting fluid barriers. The saccule is at particular risk due to its proximity to the surgical area and may explain immediate and long-term post-operative vertigo. Round window insertion may be less traumatic to the inner ear, however it may affect the vestibular receptors.
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http://dx.doi.org/10.3389/fneur.2021.663722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8058461PMC
April 2021

Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth.

Trends Hear 2021 Jan-Dec;25:2331216521999139

National Centre for Audiology, Western University, London, Ontario, Canada.

Direct drive hearing devices, which deliver a signal directly to the middle ear by vibrating the tympanic membrane via a lens placed in contact with the umbo, are designed to provide an extension of audible bandwidth, but there are few studies of the effects of these devices on preference, speech intelligibility, and loudness. The current study is the first to compare aided speech understanding between narrow and extended bandwidth conditions for listeners with hearing loss while fitted with a direct drive hearing aid system. The study also explored the effect of bandwidth on loudness perception and investigated subjective preference for bandwidth. Fifteen adult hearing aid users with symmetrical sensorineural hearing loss participated in a prospective, within-subjects, randomized single-blind repeated-measures study. Participants wore the direct drive hearing aids for 4 to 15 weeks (average 6 weeks) prior to outcome measurement. Outcome measures were completed in various bandwidth conditions achieved by reducing the gain of the device above 5000 Hz or by filtering the stimuli. Aided detection thresholds provided evidence of amplification to 10000 Hz. A significant improvement was found in high-frequency consonant detection and recognition, as well as for speech in noise performance in the full versus narrow bandwidth conditions. Subjective loudness ratings increased with provision of the full bandwidth available; however, real-world trials showed most participants were able to wear the full bandwidth hearing aids with only small adjustments to the prescription method. The majority of participants had either no preference or a preference for the full bandwidth setting.
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http://dx.doi.org/10.1177/2331216521999139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8060758PMC
May 2021

Aeration of the Human Prussak's Space: A 3D Synchrotron Imaging Study.

Otol Neurotol 2021 08;42(7):e894-e904

Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University.

Objectives: Prussak's space (PS) is an intricate middle ear region which may play an essential role in the development of middle ear disease. The three-dimensional (3D) anatomy of the human PS and its drainage routes remain relatively unknown. Earlier studies have histologically analyzed PS, by micro-dissection and endoscopy. Here, we used synchrotron-radiation phase-contrast imaging (SR-PCI), 3D reconstructions, and modeling to study the framework of the human PS, including aeration pathways. It may lead to increased understanding of development of middle ear pathology.

Design: Nine human temporal bone specimens underwent in-line SR-PCI at the Canadian Light Source in Saskatoon, Saskatchewan, Canada. Data were processed with volume-rendering software to create 3D reconstructions using scalar opacity mapping and segmentations to visualize its walls in fixed, undecalcified human temporal bones.

Results: The PS was found to be an irregular, variably shaped chamber with different aeration systems. Three different drainage pathways were found: 1) via the posterior malleolar pouch of von Tröltsch in seven of nine ears; 2) directly posterior-inferior into the mesotympanum medial to the posterior malleolar pouch in one ear; and 3) anteriorly in another. The posterior-inferior communications depended on the anatomy of the posterior malleolar fold. In one bilateral case, the aeration differed between the ears. Earlier descriptions of upper ventilation routes between the PS and the epitympanic spaces could not be substantiated.

Conclusions: The 3D anatomy of the membrane folds organizing the PS in humans was demonstrated for the first time using in-line SR-PCI. The PS was always aerated into the mesotympanum, suggesting its relative independence of attic ventilation. The impact of its various drainage routes on middle ear ventilation and disease were discussed.
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http://dx.doi.org/10.1097/MAO.0000000000003127DOI Listing
August 2021

Spike Generators and Cell Signaling in the Human Auditory Nerve: An Ultrastructural, Super-Resolution, and Gene Hybridization Study.

Front Cell Neurosci 2021 16;15:642211. Epub 2021 Mar 16.

Section of Otolaryngology, Department of Surgical Sciences, Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden.

The human auditory nerve contains 30,000 nerve fibers (NFs) that relay complex speech information to the brain with spectacular acuity. How speech is coded and influenced by various conditions is not known. It is also uncertain whether human nerve signaling involves exclusive proteins and gene manifestations compared with that of other species. Such information is difficult to determine due to the vulnerable, "esoteric," and encapsulated human ear surrounded by the hardest bone in the body. We collected human inner ear material for nanoscale visualization combining transmission electron microscopy (TEM), super-resolution structured illumination microscopy (SR-SIM), and RNA-scope analysis for the first time. Our aim was to gain information about the molecular instruments in human auditory nerve processing and deviations, and ways to perform electric modeling of prosthetic devices. Human tissue was collected during trans-cochlear procedures to remove petro-clival meningioma after ethical permission. Cochlear neurons were processed for electron microscopy, confocal microscopy (CM), SR-SIM, and high-sensitive hybridization for labeling single mRNA transcripts to detect ion channel and transporter proteins associated with nerve signal initiation and conductance. Transport proteins and RNA transcripts were localized at the subcellular level. Hemi-nodal proteins were identified beneath the inner hair cells (IHCs). Voltage-gated ion channels (VGICs) were expressed in the spiral ganglion (SG) and axonal initial segments (AISs). Nodes of Ranvier (NR) expressed Nav1.6 proteins, and encoding genes critical for inter-cellular coupling were disclosed. Our results suggest that initial spike generators are located beneath the IHCs in humans. The first NRs appear at different places. Additional spike generators and transcellular communication may boost, sharpen, and synchronize afferent signals by cell clusters at different frequency bands. These instruments may be essential for the filtering of complex sounds and may be challenged by various pathological conditions.
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http://dx.doi.org/10.3389/fncel.2021.642211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8008129PMC
March 2021

Three-dimensional tonotopic mapping of the human cochlea based on synchrotron radiation phase-contrast imaging.

Sci Rep 2021 Feb 24;11(1):4437. Epub 2021 Feb 24.

School of Biomedical Engineering, Western University, 1152 Richmond St, London, ON, N6A 3K7, Canada.

The human cochlea transforms sound waves into electrical signals in the acoustic nerve fibers with high acuity. This transformation occurs via vibrating anisotropic membranes (basilar and tectorial membranes) and frequency-specific hair cell receptors. Frequency-positions can be mapped within the cochlea to create a tonotopic chart which fits an almost-exponential function with lowest frequencies positioned apically and highest frequencies positioned at the cochlear base (Bekesy 1960, Greenwood 1961). To date, models of frequency positions have been based on a two-dimensional analysis with inaccurate representations of the cochlear hook region. In the present study, the first three-dimensional frequency analysis of the cochlea using dendritic mapping to obtain accurate tonotopic maps of the human basilar membrane/organ of Corti and the spiral ganglion was performed. A novel imaging technique, synchrotron radiation phase-contrast imaging, was used and a spiral ganglion frequency function was estimated by nonlinear least squares fitting a Greenwood-like function (F = A (10 - K)) to the data. The three-dimensional tonotopic data presented herein has large implications for validating electrode position and creating customized frequency maps for cochlear implant recipients.
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http://dx.doi.org/10.1038/s41598-021-83225-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904830PMC
February 2021

Comparison of machine learning models to classify Auditory Brainstem Responses recorded from children with Auditory Processing Disorder.

Comput Methods Programs Biomed 2021 Mar 17;200:105942. Epub 2021 Jan 17.

Department of Electrical & Computer Engineering, Western University, London, Ontario, Canada; National Centre for Audiology, Western University, London, Ontario, Canada; School of Biomedical Engineering, Western University, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, Canada.

Introduction: Auditory brainstem responses (ABRs) offer a unique opportunity to assess the neural integrity of the peripheral auditory nervous system in individuals presenting with listening difficulties. ABRs are typically recorded and analyzed by an audiologist who manually measures the timing and quality of the waveforms. The interpretation of ABRs requires considerable experience and training, and inappropriate interpretation can lead to incorrect judgments about the integrity of the system. Machine learning (ML) techniques may be a suitable approach to automate ABR interpretation and reduce human error.

Objectives: The main objective of this paper was to identify a suitable ML technique to automate the analysis of ABR responses recorded as a part of the electrophysiological testing in the Auditory Processing Disorder clinical test battery.

Methods: ABR responses recorded during routine clinical assessment from 136 children being evaluated for auditory processing difficulties were analyzed using several common ML algorithms: Support Vector Machines (SVM), Random Forests (RF), Decision Trees (DT), Gradient Boosting (GB), Extreme Gradient Boosting (Xgboost), and Neural Networks (NN). A variety of signal feature extraction techniques were used to extract features from the ABR waveforms as inputs to the ML algorithms. Statistical significance testing and confusion matrices were used to identify the most robust model capable of accurately identifying neurological abnormalities present in ABRs.

Results: Clinically significant features in the time-frequency representation of the signal were identified. The ML model trained using the Xgboost algorithm was identified as the most robust model with an accuracy of 92% compared to other models.

Conclusion: The findings of the present study demonstrate that it is possible to develop accurate ML models to automate the process of analyzing ABR waveforms recorded at suprathreshold levels. There is currently no ML-based application to screen children with listening difficulties. Therefore, it is expected that this work will be translated into an evaluation tool that can be used by audiologists in the clinic. Furthermore, this work may aid future researchers in exploring ML paradigms to improve clinical test batteries used by audiologists in achieving accurate diagnoses.
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http://dx.doi.org/10.1016/j.cmpb.2021.105942DOI Listing
March 2021

Photoacoustic Imaging of Human Vasculature Using LED versus Laser Illumination: A Comparison Study on Tissue Phantoms and In Vivo Humans.

Sensors (Basel) 2021 Jan 9;21(2). Epub 2021 Jan 9.

Department of Biomedical Engineering, Pennsylvania State University, University Park, State College, PA 16802, USA.

Vascular diseases are becoming an epidemic with an increasing aging population and increases in obesity and type II diabetes. Point-of-care (POC) diagnosis and monitoring of vascular diseases is an unmet medical need. Photoacoustic imaging (PAI) provides label-free multiparametric information of deep vasculature based on strong absorption of light photons by hemoglobin molecules. However, conventional PAI systems use bulky nanosecond lasers which hinders POC applications. Recently, light-emitting diodes (LEDs) have emerged as cost-effective and portable optical sources for the PAI of living subjects. However, state-of-art LED arrays carry significantly lower optical energy (<0.5 mJ/pulse) and high pulse repetition frequencies (PRFs) (4 KHz) compared to the high-power laser sources (100 mJ/pulse) with low PRFs of 10 Hz. Given these tradeoffs between portability, cost, optical energy and frame rate, this work systematically studies the deep tissue PAI performance of LED and laser illuminations to help select a suitable source for a given biomedical application. To draw a fair comparison, we developed a fiberoptic array that delivers laser illumination similar to the LED array and uses the same ultrasound transducer and data acquisition platform for PAI with these two illuminations. Several controlled studies on tissue phantoms demonstrated that portable LED arrays with high frame averaging show higher signal-to-noise ratios (SNRs) of up to 30 mm depth, and the high-energy laser source was found to be more effective for imaging depths greater than 30 mm at similar frame rates. Label-free in vivo imaging of human hand vasculature studies further confirmed that the vascular contrast from LED-PAI is similar to laser-PAI for up to 2 cm depths. Therefore, LED-PAI systems have strong potential to be a mobile health care technology for diagnosing vascular diseases such as peripheral arterial disease and stroke in POC and resource poor settings.
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http://dx.doi.org/10.3390/s21020424DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827532PMC
January 2021

PWD-3DNet: A Deep Learning-Based Fully-Automated Segmentation of Multiple Structures on Temporal Bone CT Scans.

IEEE Trans Image Process 2021 4;30:739-753. Epub 2020 Dec 4.

The temporal bone is a part of the lateral skull surface that contains organs responsible for hearing and balance. Mastering surgery of the temporal bone is challenging because of this complex and microscopic three-dimensional anatomy. Segmentation of intra-temporal anatomy based on computed tomography (CT) images is necessary for applications such as surgical training and rehearsal, amongst others. However, temporal bone segmentation is challenging due to the similar intensities and complicated anatomical relationships among critical structures, undetectable small structures on standard clinical CT, and the amount of time required for manual segmentation. This paper describes a single multi-class deep learning-based pipeline as the first fully automated algorithm for segmenting multiple temporal bone structures from CT volumes, including the sigmoid sinus, facial nerve, inner ear, malleus, incus, stapes, internal carotid artery and internal auditory canal. The proposed fully convolutional network, PWD-3DNet, is a patch-wise densely connected (PWD) three-dimensional (3D) network. The accuracy and speed of the proposed algorithm was shown to surpass current manual and semi-automated segmentation techniques. The experimental results yielded significantly high Dice similarity scores and low Hausdorff distances for all temporal bone structures with an average of 86% and 0.755 millimeter (mm), respectively. We illustrated that overlapping in the inference sub-volumes improves the segmentation performance. Moreover, we proposed augmentation layers by using samples with various transformations and image artefacts to increase the robustness of PWD-3DNet against image acquisition protocols, such as smoothing caused by soft tissue scanner settings and larger voxel sizes used for radiation reduction. The proposed algorithm was tested on low-resolution CTs acquired by another center with different scanner parameters than the ones used to create the algorithm and shows potential for application beyond the particular training data used in the study.
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http://dx.doi.org/10.1109/TIP.2020.3038363DOI Listing
May 2021

Does the position of interference screw in tibial tunnel effect anatomic orientation in single bundle anterior cruciate ligament reconstruction?

Asia Pac J Sports Med Arthrosc Rehabil Technol 2020 Oct 16;22:15-19. Epub 2020 Jul 16.

Thammasat University Hospital, Pathum Thani, Thailand.

Background/objective: The purpose of the study was to evaluate the change in orientation of the reconstructed ACL with the change in position of the interference screw in the tibial tunnel.

Method: It was a retrospective review of Magnetic Resonance Imaging (MRI) in which 51 normal and 61 MRI of patients who had undergone ACL reconstruction at our institute were evaluated. Postoperative ACL reconstruction group MRI studies were obtained and evaluated by two sports medicine fellows independently to assess the position of interference screw, distance of the graft from the anterior cortex of tibia and inclination of the graft. The data was collected and compared with MRI data of normal ACL patients.

Results: There were total 61 patients with ACL reconstruction. 32 patients had anterior screw placement and 29 patients had posterior screw placement in the tibial tunnel. The distance of the graft from the anterior cortex was 39.18% in ACL intact group, 50.35% in anterior screw group and 41.64% in posterior screw group. The inclination angle was 44.49⁰ in intact group, 49.69° and 42.20° in anterior and posterior screw group respectively. The difference between intact group and anterior screw group was statistically significant.

Conclusion: Posterior position of interference screw in tibial tunnel increases graft obliquity than anterior position and decreases its distance from the anterior tibial cortex. This increased graft obliquity and distance from the anterior tibial cortex is similar to the native ACL.
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http://dx.doi.org/10.1016/j.asmart.2020.06.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7640898PMC
October 2020

Competition between the hydrogen bond and the halogen bond in a [CHOH-CCl] complex: a matrix isolation IR spectroscopy and computational study.

Phys Chem Chem Phys 2020 Oct;22(39):22465-22476

Department of Chemistry, Birla Institute of Technology and Science, Vidya Vihar, Pilani, Rajasthan - 333031, India.

Methanol (CH3OH) is the simplest alcohol and carbon tetrachloride (CCl4) is widely used as a solvent in the chemical industry. CH3OH and CCl4 are both important volatile substances in the atmosphere and CCl4 is an important precursor for atmospheric ozone depletion. Moreover, mixtures of CH3OH and CCl4 are an important class of non-aqueous mixtures as they exhibit a large deviation from Raoult's law. The specific interaction between CH3OH and CCl4 is not yet investigated experimentally. The interaction between CH3OH and CCl4 at the molecular level can be twofold: hydrogen bond (O-HCl) and halogen bond (C-ClO) interaction. One halogen bonded minimum and two hydrogen bonded minima are identified in the dimer potential energy surface. Herein, the 1 : 1 complex of [CH3OH-CCl4] has been characterised using matrix-isolation infrared spectroscopy and electronic structure calculations to investigate the competition between hydrogen bonded and halogen bonded complexes. Vibrational spectra have been monitored in the C-Cl, C-O, and O-H stretching regions. The exclusive formation of halogen bonded 1 : 1 complexes in argon and nitrogen matrices is confirmed by a combination of experimental and simulated vibrational frequency, stabilisation energy, energy decomposition analysis, and natural bond orbital and atoms-in-molecules analyses. This investigation helps to understand the specific interactions in the [CH3OH-CCl4] mixture and also the possibilities of formation of halogen bonded atmospheric complexes that may influence the atmospheric chemical activities, and enhance aerosol formation and deposition of CCl4.
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http://dx.doi.org/10.1039/d0cp03855eDOI Listing
October 2020

Sound Quality Ratings of Amplified Speech and Music Using a Direct Drive Hearing Aid: Effects of Bandwidth.

Otol Neurotol 2021 02;42(2):227-234

National Centre for Audiology, Western University, Department of Otolarygology.

Objective: To determine sound quality for extended bandwidth amplification using a direct drive hearing device.

Study Design: Prospective double-blind within-subjects repeated measures study.

Setting: University hearing research laboratories.

Patients: Fifteen experienced hearing aid users with symmetric mild-sloping-to-severe sensorineural hearing loss.

Interventions: Sound quality ratings of speech and music passages were obtained using the Multiple Stimulus with Hidden References and Anchors (MUSHRA) protocol after wearing a direct drive hearing aid for at least 4 weeks. Passages were processed to filter out low-frequency (below 123 and 313 Hz) and high-frequency (above 4455, 5583, 6987, and 10,869 Hz) energy.

Main Outcome Measures: Comparison of sound quality ratings for speech and music between low and high-pass filter frequencies measured from 0 to 100, where 0 represents "bad" and 100 represents "excellent."

Results: Wider bandwidth stimuli received higher sound quality ratings compared with narrower bandwidth stimuli. Conditions with more low-frequency energy (full-band and 123 Hz cut-off) were rated as having higher sound quality. More low-frequency energy in the 123 Hz condition was rated as having higher sound versus the 313 Hz condition (mean difference: 11.2%, p = 0.001). Full-band conditions with more low- and high-frequency energy were higher than the other high-frequency cutoff conditions (mean difference range: 12.9-15%, p < 0.001).

Conclusions: The direct drive system provides higher sound quality of both speech and music compared to narrowband conditions. Sound quality improvements were mainly attributable to low-frequency sound, but stimuli with specific high-frequency content were rated with higher sound quality when additional high-frequency energy was present.
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http://dx.doi.org/10.1097/MAO.0000000000002915DOI Listing
February 2021

Clinico-Laboratory Profile, Complications and Therapeutic Outcome of Scrub Typhus in Children.

J Nepal Health Res Counc 2020 Sep 8;18(2):282-287. Epub 2020 Sep 8.

Ministry of Health and population, Kathmandu, Nepal.

Background: Scrub typhus, an important cause of undifferentiated fever, is grossly neglected and often misdiagnosed in low and middle income countries like Nepal. The main aim of this study was to describe the clinico-laboratory profile, drug used in treatment, predictor of PICU admission and therapeutic outcome of serologically confirmed scrub typhus among Nepalese children.

Methods: A prospective observational study was carried out in children aged up to 14 years with serologically (IgM ELISA) diagnosed Scrub typhus, admitted in a tertiary care hospital of central Nepal between Jan 2019 to Dec 2019.

Results: All 100 children with scrub typhus presented with fever. Other symptoms and sign were cough (29%), abdominal distension (22%) hepatomegaly (45%), splenomegaly (28%), crepitation (10%) and eschar (6%). Similarly, thrombocytopenia (72%), and increased liver enzymes SGPT (51%) and SGOT (62%) were found. Co-infection with dengue (5%) brucella (5%) and UTI (5%) were seen. Thirty six percent has some form of complication. Fifty eight percent of children were treated with azithromycin and 25% treated with doxycycline. The mean length of hospital stay was 6.68 ±2.97 days with a mean duration of defervescence being 30.07 ± 26.65 hours. The increased risk of PICU admission was found in those children with crepitation in chest (OR: 15.17, 95% CI: 3.4-66.8) during presentation and those children not getting azithromycin as treatment (OR: 3.8, 95% CI: 1.2-11.7) Conclusions: Scrub typhus should be considered as a differential diagnosis in any community acquired acute undifferentiated febrile illness regardless of the presence of an eschar. Sepsis, meningitis and pneumonia are important complications. Child having crepitation on presentation has an increased chance admission in critical care unit. The child receiving azithromycin has less chance to land in PICU.
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http://dx.doi.org/10.33314/jnhrc.v18i2.2730DOI Listing
September 2020

Design, Development, and Multi-Characterization of an Integrated Clinical Transrectal Ultrasound and Photoacoustic Device for Human Prostate Imaging.

Diagnostics (Basel) 2020 Aug 7;10(8). Epub 2020 Aug 7.

Department of Biomedical Engineering, Pennsylvania State University, University Park, State College, PA 16802, USA.

The standard diagnostic procedure for prostate cancer (PCa) is transrectal ultrasound (TRUS)-guided needle biopsy. However, due to the low sensitivity of TRUS to cancerous tissue in the prostate, small yet clinically significant tumors can be missed. Magnetic resonance imaging (MRI) with TRUS fusion biopsy has recently been introduced as a way to improve the identification of clinically significant PCa in men. However, the spatial errors in coregistering the preprocedural MRI with the real-time TRUS causes false negatives. A real-time and intraprocedural imaging modality that can sensitively detect PCa tumors and, more importantly, differentiate aggressive from nonaggressive tumors could largely improve the guidance of biopsy sampling to improve diagnostic accuracy and patient risk stratification. In this work, we seek to fill this long-standing gap in clinical diagnosis of PCa via the development of a dual-modality imaging device that integrates the emerging photoacoustic imaging (PAI) technique with the established TRUS for improved guidance of PCa needle biopsy. Unlike previously published studies on the integration of TRUS with PAI capabilities, this work introduces a novel approach for integrating a focused light delivery mechanism with a clinical-grade commercial TRUS probe, while assuring much-needed ease of operation in the transrectal space. We further present the clinical potential of our device by (i) performing rigorous characterization studies, (ii) examining the acoustic and optical safety parameters for human prostate imaging, and (iii) demonstrating the structural and functional imaging capabilities using deep-tissue-mimicking phantoms. Our TRUSPA experimental studies demonstrated a field-of-view in the range of 130 to 150 degrees and spatial resolutions in the range of 300 μm to 400 μm at a soft tissue imaging depth of 5 cm.
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http://dx.doi.org/10.3390/diagnostics10080566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460329PMC
August 2020

The BONEBRIDGE active transcutaneous bone conduction implant: effects of location, lifts and screws on sound transmission.

J Otolaryngol Head Neck Surg 2020 Aug 10;49(1):58. Epub 2020 Aug 10.

Department of Otolaryngology - Head and Neck Surgery, Western University, London, Canada.

Background: The BONEBRIDGE (MED-EL, Innsbruck, Austria) is a bone-conduction implant used in the treatment of conductive and mixed hearing loss. The BONEBRIDGE consists of an external audio processor and a bone-conduction floating mass transducer that is surgically implanted into the skull in either the transmastoid, retrosigmoid or middle fossa regions. The manufacturer includes self-tapping screws to secure the transducer; however, self-drilling screws have also been used with success. In cases where the skull is not thick enough to house the transducer, lifts are available in a variety of sizes to elevate the transducer away from the skull. The objective of the present study was to investigate the effects of screw type, lift thickness, and implant location on the sound transmission of the BONEBRIDGE.

Method: Six cadaveric temporal bones were embalmed and dried for use in this study. In each sample, a hole was drilled in each of the three implant locations to house the implant transducer. At the middle fossa, six pairs of screw holes were pre-drilled; four pairs to be used with self-tapping screws and lifts (1, 2, 3, and 4 mm thick lifts, respectively), one pair with self-tapping screws and no lifts, and one pair with self-drilling screws and no lifts. At the transmastoid and retrosigmoid locations, one pair of screw holes were pre-drilled in each for the use of the self-tapping screws. The vibration of transmitted sound to the cochlea was measured using a laser Doppler vibrometry technique. The measurements were performed on the cochlear promontory at eight discrete frequencies (0.5, 0.75, 1, 1.5, 2, 3, 4 and 6 kHz). Vibration velocity of the cochlear wall was measured in all samples. Measurements were analyzed using a single-factor ANOVA to investigate the effect of each modification.

Results: No significant differences were found related to either screw type, lift thickness, or implant location.

Conclusions: This is the first known study to evaluate the effect of screw type, lift thickness, and implant location on the sound transmission produced by the BONEBRIDGE bone-conduction implant. Further studies may benefit from analysis using fresh cadaveric samples or in-vivo measurements.
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http://dx.doi.org/10.1186/s40463-020-00454-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418375PMC
August 2020

Towards a Low-Cost and Portable Photoacoustic Microscope for Point-of-Care and Wearable Applications.

IEEE Sens J 2020 Jul 15;20(13):6881-6888. Epub 2019 Aug 15.

Department of Biomedical Engineering, Pennsylvania State University, University Park, USA and Penn State Cancer Institute, Pennsylvania State University, Hershey, Pennsylvania, USA.

Several breakthrough applications in biomedical imaging have been reported in the recent years using advanced photoacoustic microscopy imaging systems. While two photon and other optical microscopy systems have recently emerged in portable and wearable form, there is much less work reported on the portable and wearable photoacoustic microscopy (PAM) systems. Working towards this goal, we report our studies on a low-cost and portable photoacoustic microscopy system that uses a custom fabricated 2.5 mm diameter ring ultrasound transducer integrated with a fiber-coupled laser diode. The ultrasound transducer is centered at 17.25 MHz, and shows ~ 45% and ~ 100% fractional bandwidths for ultrasound pulse-echo and photoacoustic A-line signals respectively. To achieve overall system portability, besides the imaging head, other backend imaging system components need to be readily portable as well. In this direction, we have studied the potential use of compact pre-amplifiers, scanning stages and microcontroller based data acquisition and reconstruction for photoacoustic imaging. The portable PAM system is validated by imaging phantoms embedded with light absorbing targets. Future directions that will likely help achieve a completely portable and wearable photoacoustic microscopy system are discussed.
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http://dx.doi.org/10.1109/jsen.2019.2935684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7323929PMC
July 2020

A Micro-CT and Synchrotron Imaging Study of the Human Endolymphatic Duct with Special Reference to Endolymph Outflow and Meniere's Disease.

Sci Rep 2020 05 19;10(1):8295. Epub 2020 May 19.

Department of Surgical Sciences, Head and Neck Surgery, section of Otolaryngology, Uppsala University Hospital, Departments of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden.

Meniere's disease remains enigmatic, and has no treatment with sufficient evidence. The characteristic histopathological finding is endolymphatic hydrops, suggesting either an overproduction or decreased reabsorption of endolymph in the human inner ear. This study presents the first analysis of the vascular plexus around the human endolymphatic duct using micro computed tomography and coherent synchrotron radiation with phase contrast imaging. Using a software program, data were processed by volume-rendering with scalar opacity mapping to create transparent three-dimensional reconstructions. A rich vascular plexus was discovered around the endolymphatic duct that drained into collecting channels, linked to the vestibular venous outflow system. This network is believed to make up the principal route for endolymph outflow, and its associated malfunction may result in endolymphatic hydrops and Meniere's disease.
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http://dx.doi.org/10.1038/s41598-020-65110-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7237694PMC
May 2020

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

Sci Rep 2020 May 1;10(1):7681. Epub 2020 May 1.

Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE, 751 85, Uppsala, Sweden.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41598-020-64611-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193631PMC
May 2020

Correction to: Assessment of a virtual reality temporal bone surgical simulator: a national face and content validity study.

J Otolaryngol Head Neck Surg 2020 04 22;49(1):20. Epub 2020 Apr 22.

Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada.

Following publication of the original article [1], the authors identified incorrect ordering and incorrect files being used for Figs. 1, 2 and 3.
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http://dx.doi.org/10.1186/s40463-020-00416-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178585PMC
April 2020

Assessment of a virtual reality temporal bone surgical simulator: a national face and content validity study.

J Otolaryngol Head Neck Surg 2020 Apr 7;49(1):17. Epub 2020 Apr 7.

Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada.

Background: Trainees in Otolaryngology-Head and Neck Surgery must gain proficiency in a variety of challenging temporal bone surgical techniques. Traditional teaching has relied on the use of cadavers; however, this method is resource-intensive and does not allow for repeated practice. Virtual reality surgical training is a growing field that is increasingly being adopted in Otolaryngology. CardinalSim is a virtual reality temporal bone surgical simulator that offers a high-quality, inexpensive adjunct to traditional teaching methods. The objective of this study was to establish the face and content validity of CardinalSim through a national study.

Methods: Otolaryngologists and resident trainees from across Canada were recruited to evaluate CardinalSim. Ethics approval and informed consent was obtained. A face and content validity questionnaire with questions categorized into 13 domains was distributed to participants following simulator use. Descriptive statistics were used to describe questionnaire results, and either Chi-square or Fishers exact tests were used to compare responses between junior residents, senior residents, and practising surgeons.

Results: Sixty-two participants from thirteen different Otolaryngology-Head and Neck Surgery programs were included in the study (32 practicing surgeons; 30 resident trainees). Face validity was achieved for 5 out of 7 domains, while content validity was achieved for 5 out of 6 domains. Significant differences between groups (p-value of < 0.05) were found for one face validity domain (realistic ergonomics, p = 0.002) and two content validity domains (teaching drilling technique, p = 0.011 and overall teaching utility, p = 0.006). The assessment scores, global rating scores, and overall attitudes towards CardinalSim, were universally positive. Open-ended questions identified limitations of the simulator.

Conclusion: CardinalSim met acceptable criteria for face and content validity. This temporal bone virtual reality surgical simulation platform may enhance surgical training and be suitable for patient-specific surgical rehearsal for practicing Otolaryngologists.
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http://dx.doi.org/10.1186/s40463-020-00411-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7137498PMC
April 2020
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