Dr. Zhongwei (Tim) Zhi Profile

Dr. Zhongwei (Tim) Zhi

at Masimo

SPIE Involvement:

Author

Publications (13)

Proceedings Article | 20 March 2015 Paper

Characterization of rat model of acute anterior uveitis using optical coherence tomography angiography

Woo June Choi, Kathryn Pepple, Zhongwei Zhi, Ruikang Wang

Proceedings Volume 9307, 93071Z (2015) https://doi.org/10.1117/12.2080484

KEYWORDS: Optical coherence tomography, Image segmentation, Inflammation, Iris, Eye, Angiography, Eye models, Cornea, Tissues, Iris recognition

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SPIE Journal Paper | 16 January 2015 Open Access

Optical coherence tomography based microangiography for quantitative monitoring of structural and vascular changes in a rat model of acute uveitis in vivo: a preliminary study

Woo June Choi, Kathryn Pepple, Zhongwei Zhi, Ruikang Wang

JBO, Vol. 20, Issue 01, 016015, (January 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.1.016015

KEYWORDS: Optical coherence tomography, Iris, Inflammation, Image segmentation, Eye models, Eye, In vivo imaging, Iris recognition, Angiography, Animal model studies

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SPIE Journal Paper | 7 August 2013 Open Access

Label-free optical lymphangiography: development of an automatic segmentation method applied to optical coherence tomography to visualize lymphatic vessels using Hessian filters

Siavash Yousefi, Jia Qin, Zhongwei Zhi, Ruikang Wang

JBO, Vol. 18, Issue 08, 086004, (August 2013) https://doi.org/10.1117/12.10.1117/1.JBO.18.8.086004

KEYWORDS: Lymphatic system, Image segmentation, Optical coherence tomography, Visualization, Ear, Tissues, Blood vessels, Wound healing, Tissue optics, Image filtering

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Proceedings Article | 26 March 2013 Paper

High quality optical microangiography of ocular microcirculation and measurement of total retinal blood flow in mouse eye

Zhongwei Zhi, Xin Yin, Suzan Dziennis, Charles Alpers, Ruikang Wang

Proceedings Volume 8567, 856728 (2013) https://doi.org/10.1117/12.2005222

KEYWORDS: Blood circulation, Optical coherence tomography, Eye, Retina, Arteries, Optic nerve, Doppler effect, Doppler tomography, Head, Visualization

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Proceedings Article | 20 March 2013 Paper

Phase-sensitive optical coherence tomography characterization of pulse-induced trabecular meshwork displacement in ex vivo non-human primate eyes

Peng Li, Roberto Reif, Zhongwei Zhi, Lin An, Elizabeth Martin, Tueng Shen, Murray Johnstone, Ruikang Wang

Proceedings Volume 8571, 85711S (2013) https://doi.org/10.1117/12.2006992

KEYWORDS: Optical coherence tomography, Tissues, Mercury, Eye, Tissue optics, Imaging systems, Veins, Resistance, Image segmentation, Visualization

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Purpose. It is suspected that the abnormalities of aqueous outflow pump composed of trabecular meshwork (TM) and Schlemm’s canal (SC) results in the increased outflow resistance and then elevated intraocular pressure (IOP) in initial glaucoma. In order to explore the casual mechanism and the early diagnosis of glaucoma, the dynamic characterizations of aqueous outflow pump were explored.
Methods. As a functional extension of optical coherence tomography (OCT), tissue Doppler OCT (tissue-DOCT) method capable of measuring the slow tissue movement was developed. The tissue-DOCT imaging was conducted on the corneo-scleral limbus of 4 monkey eyes. The eye was mounted in an anterior segment holder, together with a perfusion system to control the mean IOP and to induce the cyclic IOP transients with amplitude 3 mm Hg at frequency 1 pulse/second. IOP was monitored on-line by a pressure transducer. Tissue-DOCT data and pressure data were recorded simultaneously. The IOP-transient induced Doppler velocity, displacement and strain rate of TM and the normalized area of SC were quantified at 7 different mean IOPs (5, 8, 10, 20, 30, 40, 50 mm Hg).
Results. The outflow system, including TM, SC and CCs, was visualized in the micro-structural imaging. The IOP-transient induced pulsatile TM movement and SC deformation were detected and quantified by tissue-DOCT. The TM movement was depth-dependent and the largest movement was located in the area closest to SC endothelium (SCE). Both the pulsations of TM and SC were found to be synchronous with the IOP pulse wave. At 8 mm Hg IOP, the global TM movement was around 0.65μm during one IOP transient. As IOP elevated, a gradual attenuation of TM movement and SC deformation was observed.
Conclusions. The observed pulsation of TM and SC induced by the pulsatile IOP transients was in good agreement with the predicated role of TM and SC acting as a biomechanical pump (pumping aqueous from anterior chamber into SC and from SC into CCs) in the aqueous outflow system. As the IOP elevated, the attenuated pulsation amplitude of the aqueous outflow pump indicated the failure of the mechanical pump and the increase of aqueous outflow resistance. The promising results revealed the potential of using the proposed tissue-DOCT for diagnosis and associated therapeutic guidance of the initial and progressive glaucoma process by monitoring the pulsation of the outflow pump.

SPIE Journal Paper | 1 October 2012 Open Access

Effects of hypoxia on cochlear blood flow in mice evaluated using Doppler optical microangiography

Suzan Dziennis, Roberto Reif, Zhongwei Zhi, Alfred Nuttall, Ruikang Wang

JBO, Vol. 17, Issue 10, 106003, (October 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.10.106003

KEYWORDS: Blood circulation, Hypoxia, Doppler effect, Optical coherence tomography, Blood vessels, Oxygen, Arteries, Blood, 3D image processing, Tissue optics

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SPIE Journal Paper | 24 July 2012 Open Access

Phase-sensitive optical coherence tomography characterization of pulse-induced trabecular meshwork displacement in ex vivo nonhuman primate eyes

Peng Li, Roberto Reif, Zhongwei Zhi, Tueng Shen, Ruikang Wang, Elizabeth Martin, Murray Johnstone

JBO, Vol. 17, Issue 7, 076026, (July 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.7.076026

KEYWORDS: Optical coherence tomography, Tissues, Eye, In vivo imaging, Imaging systems, Adaptive optics, Image segmentation, Visualization, Eye models, Visual system

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SPIE Journal Paper | 1 August 2011 Open Access

Ultrahigh sensitive optical microangiography reveals depth-resolved microcirculation and its longitudinal response to prolonged ischemic event within skeletal muscles in mice

Yali Jia, Jia Qin, Zhongwei Zhi, Ruikang Wang

JBO, Vol. 16, Issue 08, 086004, (August 2011) https://doi.org/10.1117/12.10.1117/1.3606565

KEYWORDS: Blood circulation, Tissues, Blood, Arteries, Capillaries, Tissue optics, Biomedical optics, Ischemia, 3D image processing, Image segmentation

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Proceedings Article | 12 February 2011 Paper

Ultra high resolution ultra high sensitive optical micro-angiography based on super continuum light source

Lin An, Jia Qin, Zhongwei Zhi, Ruikang Wang

Proceedings Volume 7889, 788915 (2011) https://doi.org/10.1117/12.875365

KEYWORDS: Image resolution, Light sources, Imaging systems, Optical coherence tomography, Blood, In vivo imaging, Visualization, Tissue optics, Blood vessels, CMOS cameras

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Proceedings Article | 12 February 2011 Paper

Label-free 3D optical imaging of microcirculation within sentinel lymph node in vivo

Yeongri Jung, Zhongwei Zhi, Ruikang Wang

Proceedings Volume 7889, 788910 (2011) https://doi.org/10.1117/12.875682

KEYWORDS: Lymphatic system, In vivo imaging, 3D image processing, Tissue optics, Cancer, Optical coherence tomography, Optical imaging, Tissues, Visualization, Scattering

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Proceedings Article | 11 February 2011 Paper

Smart velocity ranging quantifiable optical microangiography

Zhongwei Zhi, Ruikang Wang

Proceedings Volume 7898, 78980K (2011) https://doi.org/10.1117/12.875712

KEYWORDS: Blood circulation, Ranging, Optical coherence tomography, Tissue optics, In vivo imaging, Cerebral blood flow, Capillaries, 3D image processing, Doppler tomography, Visualization

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Proceedings Article | 11 February 2011 Paper

High sensitive volumetric imaging of renal microcirculation in vivo using ultrahigh sensitive optical microangiography

Zhongwei Zhi, Yeongri Jung, Yali Jia, Lin An, Ruikang Wang

Proceedings Volume 7898, 789816 (2011) https://doi.org/10.1117/12.875694

KEYWORDS: Ischemia, Optical coherence tomography, Capillaries, Kidney, In vivo imaging, Blood circulation, 3D image processing, Tissue optics, Arteries, Imaging systems

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SPIE Journal Paper | 1 September 2010 Open Access

Three-dimensional optical imaging of microvascular networks within intact lymph node in vivo

Yeongri Jung, Zhongwei Zhi, Ruikang Wang

JBO, Vol. 15, Issue 05, 050501, (September 2010) https://doi.org/10.1117/12.10.1117/1.3496301

KEYWORDS: Lymphatic system, Tissues, In vivo imaging, 3D image processing, Optical coherence tomography, Blood vessels, Tissue optics, Blood circulation, Visualization, Blood

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