University of Southern California

University of Southern California Receives NIH Grant for Mechanisms of cochlear synaptopathy after noise or blast trauma

University of Southern California Receives a 2023 NIH Grant for $516,926 for Mechanisms of cochlear synaptopathy after noise or blast trauma.  The principal investigator is John S. Oghalai.  Below is a summary of the proposed study. About 15% of Americans have hearing loss due to noise exposure. The classical explanation is trauma to the cochlear hair cells. An additional mechanism of noise-induced hearing loss is cochlear synaptopathy. There are no effective treatments used clinically to prevent hearing loss via either mechanism after traumatic noise exposure. Recently, we identified that endolymphatic hydrops occurs after blast or noise trauma, and that endolymphatic hydrops correlated with cochlear synaptopathy. Our central hypothesis is that endolymphatic hydrops is a surrogate marker for swelling of auditory nerve dendrites that occurs in response to glutamate excitotoxicity. We will test this hypothesis with three aims. First, we will determine whether swelling of auditory ...

High speed photo-mediated ultrasound therapy integrated with OCTA

, , , , , , , ,

Photo-mediated Ultrasound Therapy (PUT), as a new anti-vascular technique, can promote cavitation activity to selectively destruct blood vessels with a significantly lower amount of energy when compared to energy level required by other laser and ultrasound treatment therapies individually. Here, we report the development of a high speed PUT system based on a 50-kHz pulsed laser to achieve faster treatment, decreasing the treatment time by a factor of 20. Furthermore, we integrated it with optical coherence tomography angiography (OCTA) for real time monitoring. The feasibility of the proposed OCTA-guided PUT was validated through in vivo rabbit experiments. The addition of OCTA to PUT allows for quantitative prescreening and real time monitoring of treatment response, thereby enabling implementation of individualized treatment strategies. ( Read Full Article )

Association of Optical Coherence Tomography–Measured Fibrovascular Ridge Thickness and Clinical Disease Stage in Retinopathy of Prematurity

, , , , , , , , , ,

Importance Accurate diagnosis of retinopathy of prematurity (ROP) is essential to provide timely treatment and reduce the risk of blindness. However, the components of an ROP examination are subjective and qualitative. Objective To evaluate whether optical coherence tomography (OCT)–derived retinal thickness measurements at the vascular-avascular junction are associated with clinical diagnosis of ROP stage. Design, Setting, and Participants This cross-sectional longitudinal study compared OCT-based ridge thickness calculated from OCT B-scans by a masked examiner to the clinical diagnosis of 2 masked examiners using both traditional stage classifications and a more granular continuous scale at the neonatal intensive care unit (NICU) of Oregon Health & Science University (OHSU) Hospital. Infants who met ROP screening criteria in the OHSU NICU between June 2021 and April 2022 and had guardian consent were included. One OCT volume and en face image per patient per eye showing ...

Repeatability and Reproducibility of 4.5 by 4.5 mm Peripapillary Optical Coherence Tomography Angiography Scans in Glaucoma and Non-Glaucoma Eyes

, , , , , , , , , , , , ,

Précis: Peripapillary vessel parameters from optical coherence tomography angiography (OCTA) 4.5×4.5 mm scans in nonglaucomatous and glaucomatous eyes showed high repeatability and reproducibility, with higher reliability for commercially developed OCTA parameters compared with custom OCTA parameters. Purpose: The purpose of this study was to assess intrasession repeatability versus intersession reproducibility of peripapillary vessel parameters from 4.5×4.5 mm OCTA scans in nonglaucomatous eyes and glaucomatous eyes. Materials and Methods: In a longitudinal study, peripapillary OCTA scans were quantified using research-oriented custom quantification software that calculated vessel area density (VAD) and flux and clinic-oriented commercially developed software (Cirrus 11.0) that calculated perfusion density (PD) and flux index (FI). Intrasession repeatability and intersession reproducibility were evaluated using within-eye coefficient of variation (C...

University of Southern California Receives NIH Grant for Role of tonic outer hair cell motility in cochlear amplification

University of Southern California Received a 2022 NIH Grant for $165,000 for Role of tonic outer hair cell motility in cochlear amplification. The principal investigator is James Dewey. Below is a summary of the proposed study. Mammalian hearing sensitivity depends on outer hair cells (OHCs), which change length and generate force to amplify sound-evoked vibrations within the cochlea. While it is often assumed that amplification depends on cycle-by-cycle OHC motility, the ability of this mechanism to operate at sufficiently high frequencies in vivo has been questioned, and exactly how OHCs interact with the surrounding organ of Corti structures to produce amplification remains unclear. Clarifying how OHCs work is critical to understanding and restoring what is missing in ears with OHC damage, which is a common cause of hearing loss. As a step toward this, the proposed work will determine whether, in addition to fast, cycle-by-cycle length changes, OHCs undergo sustained, tonic lengt...

University of Southern California Receives NIH Grant for Long-wavelength 1.7-micron optical coherence tomography for otologic imaging and hearing research

University of Southern California Received a 2022 NIH Grant for $67,582 for Long-wavelength 1.7-micron optical coherence tomography for otologic imaging and hearing research. The principal investigator is Jack Tang. Below is a summary of the proposed work. Hearing loss affects the quality of life in nearly one-in-four adults in the United States, yet in many cases it is difficult to identify the cause. CT imaging can provide high-resolution contrast in the small bony structures in the middle/inner ear, and MRI can provide medium-resolution contrast in soft tissues, but there exists a need for high-resolution imaging of the soft cochlear tissues. Optical coherence tomography (OCT) is one technology that can fill this need and is gaining traction as a potential method for non-invasive otologic imaging due to its ability to record high-resolution volumetric images, blood flow, and vibrations through several millimeters of tissue. These advantages have also made OCT a popular tool in ba...

Repeatability and Reproducibility of 4.5 by 4.5 mm Peripapillary Optical Coherence Tomography Angiography Scans in Glaucoma and Nonglaucoma Eyes

, , , , , , , , , , , , ,

Prcis: Peripapillary vessel parameters from optical coherence tomography angiography (OCTA) 4.5×4.5 mm scans in nonglaucomatous and glaucomatous eyes showed high repeatability and reproducibility, with higher reliability for commercially developed OCTA parameters compared with custom OCTA parameters. Purpose: The purpose of this study was to assess intrasession repeatability versus intersession reproducibility of peripapillary vessel parameters from 4.5×4.5 mm OCTA scans in nonglaucomatous eyes and glaucomatous eyes. Materials and methods: In a longitudinal study, peripapillary OCTA scans were quantified using research-oriented custom quantification software that calculated vessel area density (VAD) and flux and clinic-oriented commercially developed software (Cirrus 11.0) that calculated perfusion density (PD) and flux index (FI). Intrasession repeatability and intersession reproducibility were evaluated using within-eye coefficient of variation (CVW) and intraclass cor...

University of Southern California Receives NIH Grant for Cochlear mechanics in the mouse

University of Southern California Received a 2022 NIH Grant for $623,326 for Cochlear mechanics in the mouse. The principal investigator is John Oghalai. Below is a summary of the proposed work. Sound pressure produces force across the mammalian cochlear partition, ultimately creating a vibratory traveling wave that propagates longitudinally up the cochlear duct. The key feature distinguishing this process from the non-mammalian cochlea is amplification, whereby forces produced by thousands of outer hair cells (OHCs) sharpen and amplify the traveling wave. Our overarching objective is to understand how the complex biomechanics of the 3D multi-cellular and acellular arrangement that form the organ of Corti work together to create cochlear amplification. Specifically, we will determine how this process, which stems from the broadly- tuned basilar membrane, creates sharp frequency tuning and high sensitivity. This question is significant on a basic science level because these biophysic...

Advanced Imaging of the Biliary System and Pancreas

,

Despite advances in noninvasive techniques for imaging the pancreaticobiliary system, several disease processes including indeterminate biliary strictures as well as neuroendocrine tumors, inflammatory pseudotumors, and complex cysts of the pancreas remain difficult to characterize. New endoscopic imaging technologies have emerged to address these challenges. Cholangioscopy and intraductal ultrasound (IDUS) are powerful tools to characterize subtle biliary concretions and strictures. Confocal Laser Endomicroscopy (CLE) and Optical Coherence Tomography (OCT) are emerging approaches for the most difficult biliary lesions. Contrast harmonic endoscopic ultrasound (CH-EUS), elastography, and 3D-EUS are improving the approach to subtle pancreatic lesions, particularly in the context of indeterminate tissue sampling. Pancreatoscopy, pancreatic IDUS, and intracystic CLE hold promise to further improve the assessment of pancreatic cysts. We aim to comprehensively review the emerging clinical...

OCTA Derived Vessel Skeleton Density Versus Flux and Their Associations With Systemic Determinants of Health

, , , , ,

Purpose: To examine the associations of optical coherence tomography angiography (OCTA)-derived retinal capillary flux with systemic determinants of health. Methods: This is a cross-sectional study of subjects recruited from the African American Eye Disease Study. A commercially available swept-source (SS)-OCTA device was used to image the central 3 × 3 mm macular region. Retinal capillary perfusion was assessed using vessel skeleton density (VSD) and flux. Flux approximates the number of red blood cells moving through vessel segments and is a novel metric, whereas VSD is a previously validated measure commonly used to quantify capillary density. The associations of OCTA derived measures with systemic determinants of health were evaluated using multivariate generalized linear mixed-effects models. Results: A total of 154 eyes from 83 participants were enrolled. Mean VSD and flux were 0.148 ± 0.009 and 0.156 ± 0.016, respectively. In a model containing age, systol...

Wedge Defects on Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma

, , , , , , , , , ,

Precis: Among subjects with glaucoma, wedge-shaped defects on optical coherence tomography angiography were associated with disc hemorrhages, paracentral visual field defects, increased cup-to-disc ratio, and thinner retinal nerve fiber layer. Purpose: To examine determinants of wedge defects on peripapillary optical coherence tomography angiography (OCTA) in glaucoma. Methods: 278 eyes of 186 subjects with mild to severe primary open angle glaucoma (POAG) underwent 6×6 spectral domain-OCTA imaging of the superficial peripapillary retina from 2016-2020 at an academic practice. Wedge defects were defined as focal microvasculature loss that extends outward from the optic nerve in an arcuate, wedge shape. Logistic regression models controlling for inter-eye correlation identified variables significantly associated with wedge defects. Eyes with profound microvasculature loss in both hemispheres were excluded. Candidate variables included: age, gender, race or ethnicity, diabetes, ...

Capillary density and caliber as assessed by optical coherence tomography angiography may be significant predictors of diabetic retinopathy severity

, , , , , , , , , , , , , , ,

Purpose To validate retinal capillary density and caliber associations with diabetic retinopathy (DR) severity in different clinical settings. Methods This cross-sectional study assessed retinal capillary density and caliber in the superficial retinal layer of 3-mm OCTA scans centered on the fovea. Images were collected from non-diabetic controls and subjects with mild or referable DR (defined DR worse than mild DR) between February 2016 and December 2019 at secondary and tertiary eye care centers. Vessel Skeleton Density (VSD), a measure of capillary density, and Vessel Diameter Index (VDI), a measure of vascular caliber, were calculated from these images. Discriminatory performance of VSD and VDI was evaluated using multivariable logistic regression models predicting DR severity with adjustments for sex, hypertension, and hyperlipidemia. Area under the curve (AUC) was estimated. Model performance was evaluated in two different cohorts. Results This study included 594 eyes from 385...

Optimal number and orientation of anterior segment OCT images to measure ocular biometric parameters in angle closure eyes: the Chinese American Eye Study

, , , , , ,

Purpose: To assess the optimal number and orientation of anterior segment optical coherence tomography (AS-OCT) images for accurately measuring ocular biometric parameters in angle closure eyes. Methods: Subjects with angle closure, defined as >3 quadrants of non-visible pigmented trabecular meshwork on static gonioscopy, were selected from the Chinese American Eye Study. Mean angle opening distance (AOD500) was calculated using four images (0°-180°, 45°-225°, 90°-270° and 135°-315° meridians) from one eye per subject. Ten eyes from each quartile of AOD500 measurements were randomly selected for detailed 32-image analysis of 10 biometric parameters, including AOD500, iris curvature (IC), anterior chamber depth (ACD), lens vault (LV), and anterior chamber area (ACA). Mean and range of measurements from 1, 2, 4, 8 or 16 images were compared with 32-image values for all parameters. Results: 40 out of 335 eyes with angle closure were selected for 32-im...

University of Southern California Receives NIH Grant for Mechanisms of cochlear synaptopathy after noise or blast trauma

University of Southern California Received a 2022 NIH Grant for $516,925 for Mechanisms of cochlear synaptopathy after noise or blast trauma. The principal investigator is John Oghalai. Below is a summary of the proposed work. About 15% of Americans have hearing loss due to noise exposure. The classical explanation is trauma to the cochlear hair cells. An additional mechanism of noise-induced hearing loss is cochlear synaptopathy. There are no effective treatments used clinically to prevent hearing loss via either mechanism after traumatic noise exposure. Recently, we identified that endolymphatic hydrops occurs after blast or noise trauma, and that endolymphatic hydrops correlated with cochlear synaptopathy. Our central hypothesis is that endolymphatic hydrops is a surrogate marker for swelling of auditory nerve dendrites that occurs in response to glutamate excitotoxicity. We will test this hypothesis with three aims. First, we will determine whether swelling of auditory nerve den...

University of Southern California Receives NIH Grant for Optical Imaging Technologies to Identity Residual Cholesteatoma and Improve Ossiculplasty Outcomes

University of Southern California received a 2022 NIH Grant for $586,520 for Optical Imaging Technologies to Identity Residual Cholesteatoma and Improve Ossiculplasty Outcomes. The principal investigator is Brian Applegate. Below is a summary of the proposed work. There are a number of diseases and conditions in the middle ear that cause hearing loss in both children and adults. In children it is particularly important to expedite interventions to restore hearing since it negatively impacts language development and academic performance. An example is cholesteatoma, a benign lesion due to abnormal skin growth in the middle ear which facilitates erosion of bone, including the ossicles, causing permanent damage. The preferred surgical approach comes with a relatively high risk of both recurrent and residual lesions (~10%). While the initial diagnosis is typically straight forward because of the size of the lesion when the patient seeks medical care, identifying residual cholesteatoma...

Categories

Organizations in the News

OCT Companies in the News

Picture Gallery