Person: Wang, Hui
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Wang
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Hui
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Wang, Hui
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Publication as-PSOCT: Volumetric microscopic imaging of human brain architecture and connectivity(Elsevier BV, 2018-01) Wang, Hui; Magnain, Caroline; Wang, Ruopeng; Dubb, Jay; Varjabedian, Ani; Tirrell, Lee; Stevens, Allison; Augustinack, Jean; Konukoglu, Ender; Aganj, Iman; Frosch, Matthew; Schmahmann, Jeremy; Fischl, Bruce; Boas, DavidPolarization sensitive optical coherence tomography (PSOCT) with serial sectioning has enabled the investigation of 3D structures in mouse and human brain tissue samples. By using intrinsic optical properties of back-scattering and birefringence, PSOCT reliably images cytoarchitecture, myeloarchitecture and fiber orientations. In this study, we developed a fully automatic serial sectioning polarization sensitive optical coherence tomography (as-PSOCT) system to enable volumetric reconstruction of human brain samples with unprecedented sample size and resolution. The 3.5μm in-plane resolution and 50μm through-plane voxel size allow inspection of cortical layers that are a single-cell in width, as well as small crossing fibers. We show the abilities of as- PSOCT in quantifying layer thicknesses of the cerebellar cortex and creating microscopic tractography of intricate fiber networks in the subcortical nuclei and internal capsule regions, all based on volumetric reconstructions. as-PSOCT provides a viable tool for studying quantitative cytoarchitecture and myeloarchitecture and mapping connectivity with microscopic resolution in the human brain.Publication Comparing the minimum spatial-frequency content for recognizing Chinese and alphabet characters(The Association for Research in Vision and Ophthalmology, 2018) Wang, Hui; Legge, Gordon E.Visual blur is a common problem that causes difficulty in pattern recognition for normally sighted people under degraded viewing conditions (e.g., near the acuity limit, when defocused, or in fog) and also for people with impaired vision. For reliable identification, the spatial frequency content of an object needs to extend up to or exceed a minimum value in units of cycles per object, referred to as the critical spatial frequency. In this study, we investigated the critical spatial frequency for alphabet and Chinese characters, and examined the effect of pattern complexity. The stimuli were divided into seven categories based on their perimetric complexity, including the lowercase and uppercase alphabet letters, and five groups of Chinese characters. We found that the critical spatial frequency significantly increased with complexity, from 1.01 cycles per character for the simplest group to 2.00 cycles per character for the most complex group of Chinese characters. A second goal of the study was to test a space-bandwidth invariance hypothesis that would represent a tradeoff between the critical spatial frequency and the number of adjacent patterns that can be recognized at one time. We tested this hypothesis by comparing the critical spatial frequencies in cycles per character from the current study and visual-span sizes in number of characters (measured by Wang, He, & Legge, 2014) for sets of characters with different complexities. For the character size (1.2°) we used in the study, we found an invariant product of approximately 10 cycles, which may represent a capacity limitation on visual pattern recognition.Publication The Interrelationship between Refractive Error, Blood Vessel Anatomy, and Glaucomatous Visual Field Loss(The Association for Research in Vision and Ophthalmology, 2017) Wang, Mengyu; Jin, Qingying; Wang, Hui; Li, Dian; Baniasadi, Neda; Elze, TobiasPurpose We quantified the interrelationship between retinal blood vessel (BV) anatomical variation, spherical equivalent (SE) of refractive error, and functional diagnostic parameters in glaucoma to identify optimal parameters for the improvement of optical coherence tomography (OCT) retinal nerve fiber layer thickness (RNFLT) norms. Methods: A trained observer marked the intersections of the main superior/inferior temporal arteries and veins with concentric circles around the optic nerve head (ONH) center on fundus images. The interrelationship of BV, SE, and visual field global parameters was analyzed by multivariate regression and model comparison. Results: A total of 445 eyes of 445 patients in a large glaucoma practice were selected. Of all investigated BV parameters, interartery angles (IAA) between superior and inferior arteries at a radius of 1.73 mm around the ONH center demonstrated the strongest relationship to SE (Bayesian information criterion difference to null model, 11.9). SE and BV parameters are unrelated to functional parameters, including mean deviation (MD), pattern standard deviation, and glaucoma hemifield test results. Conclusions: BV locations outside the ONH are sufficiently stable over glaucoma severity to represent individual eye anatomy, and the IAA at 1.73 mm eccentricity is the optimal parameter to be considered for novel OCT RNFLT norms. Translational Relevance Among a large set of BV location parameters, considering IAA may improve RNFLT norms optimally and thereby increase the accuracy of clinical glaucoma diagnosis.Publication Evaluation of the precision of contrast sensitivity function assessment on a tablet device(Nature Publishing Group, 2017) Dorr, Michael; Lesmes, Luis A.; Elze, Tobias; Wang, Hui; Lu, Zhong-Lin; Bex, Peter J.The contrast sensitivity function (CSF) relates the visibility of a spatial pattern to both its size and contrast, and is therefore a more comprehensive assessment of visual function than acuity, which only determines the smallest resolvable pattern size. Because of the additional dimension of contrast, estimating the CSF can be more time-consuming. Here, we compare two methods for rapid assessment of the CSF that were implemented on a tablet device. For a single-trial assessment, we asked 63 myopes and 38 emmetropes to tap the peak of a “sweep grating” on the tablet’s touch screen. For a more precise assessment, subjects performed 50 trials of the quick CSF method in a 10-AFC letter recognition task. Tests were performed with and without optical correction, and in monocular and binocular conditions; one condition was measured twice to assess repeatability. Results show that both methods are highly correlated; using both common and novel measures for test-retest repeatability, however, the quick CSF delivers more precision with testing times of under three minutes. Further analyses show how a population prior can improve convergence rate of the quick CSF, and how the multi-dimensional output of the quick CSF can provide greater precision than scalar outcome measures.Publication Quantifying positional variation of retinal blood vessels in glaucoma(Public Library of Science, 2018) Wang, Mengyu; Jin, Qingying; Wang, Hui; Baniasadi, Neda; Elze, TobiasWe studied the relationship between major retinal blood vessel (BV) positions and glaucoma parameters based on pairs of Cirrus optical coherence tomography scans and Humphrey visual fields of 445 eyes from 445 glaucoma patients in our cross-sectional study. A trained observer marked the major superior and inferior temporal BV (artery and vein) positions on four concentric circles around the optic disc. Analysis of variance was performed to analyze the group differences of BV positions related to the factors of radius, BV type, myopia status and glaucoma stage. Subsequent t-tests were implemented to further study the effect of glaucoma stage on BV positions. The radial variations of BV positions were correlated to mean deviation and circumpapillary retinal nerve fiber layer thickness (cpRNFLT). We found significant main effects of BV type, radius and myopia status for superior and inferior BV positions and of glaucoma stage for superior BV positions (all p≤0.006) with significant superior artery nasalization in advanced compared to mild glaucoma on the two smallest circles (subsequent t-tests, p<0.05). In addition, MD (r = -0.10, p = 0.04) and cpRNFLT (r = -0.12, p = 0.02) were significantly correlated to the angle difference of superior arteries between the innermost and outermost circles. In conclusion, we demonstrated that peripapillary superior artery positions are significantly nasalized for advanced glaucoma.