1. Articles from K. Kirk Shung

    1-24 of 24
    1. 2D Ultrasonic Array-based Optical Coherence Elastography

      2D Ultrasonic Array-based Optical Coherence Elastography

      Acoustic radiation force optical coherence elastography (ARF-OCE) has been successfully implemented to characterize the biomechanical properties of soft tissues such as the cornea and the retina with high resolution using single-element ultrasonic transducers for ARF excitation. Most currently proposed OCE techniques, such as air-puff and ARF, have less capability to control the spatiotemporal information of the induced region of deformation, resulting in limited accuracy and low temporal resolution of the shear wave elasticity imaging. In this study, we propose a new method called 2D ultrasonic array-based optical coherence elastography imaging, which combines the advantages of 3D dynamic electronic steering of ...

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    2. Miniature probe for mapping mechanical properties of vascular lesions using acoustic radiation force optical coherence elastography

      Miniature probe for mapping mechanical properties of vascular lesions using acoustic radiation force optical coherence elastography

      Cardiovascular diseases are the leading cause of fatalities in the United States. Atherosclerotic plaques are one of the primary complications that can lead to strokes and heart attacks if left untreated. It is essential to diagnose the disease early and distinguish vulnerable plaques from harmless ones. Many methods focus on the structural or molecular properties of plaques. Mechanical properties have been shown to change drastically when abnormalities develop in arterial tissue. We report the development of an acoustic radiation force optical coherence elastography (ARF-OCE) system that uses an integrated miniature ultrasound and optical coherence tomography (OCT) probe to map the ...

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    3. Acoustic Radiation Force Optical Coherence Elastography of Corneal Tissue

      Acoustic Radiation Force Optical Coherence Elastography of Corneal Tissue

      We report on a real-time acoustic radiation force optical coherence elastography (ARF-OCE) system to map the relative elasticity of corneal tissue. A modulated ARF is used as excitation to vibrate the cornea, while OCE serves as detection of tissue response. To show feasibility of detecting mechanical contrast using this method, we performed tissue-equivalent agarose phantom studies with inclusions of a different stiffness. We obtained 3-D elastograms of a healthy cornea and a highly cross-linked cornea. Finally, we induced a stiffness change on a small portion of a cornea and observed the differences in displacement.

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      Mentions: UC Irvine
    4. Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

      Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

      Atherosclerotic coronary artery disease (CAD) is the number one cause of death worldwide. The majority of CAD-induced deaths are due to the rupture of vulnerable plaques. Accurate assessment of plaques is crucial to optimize treatment and prevent death in patients with CAD. Current diagnostic techniques are often limited by either spatial resolution or penetration depth. Several studies have proved that the combined use of optical and ultrasonic imaging techniques increase diagnostic accuracy of vulnerable plaques. Here, we introduce an ultrafast optical-ultrasonic dual-modality imaging system and flexible miniaturized catheter, which enables the translation of this technology into clinical practice. This system ...

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    5. Imaging and characterizing shear wave and shear modulus under orthogonal acoustic radiation force excitation using OCT Doppler variance method

      Imaging and characterizing shear wave and shear modulus under orthogonal acoustic radiation force excitation using OCT Doppler variance method

      We report on a novel acoustic radiation force orthogonal excitation optical coherence elastography (ARFOE-OCE) technique for imaging shear wave and quantifying shear modulus under orthogonal acoustic radiation force (ARF) excitation using the optical coherence tomography (OCT) Doppler variance method. The ARF perpendicular to the OCT beam is produced by a remote ultrasonic transducer. A shear wave induced by ARF excitation propagates parallel to the OCT beam. The OCT Doppler variance method, which is sensitive to the transverse vibration, is used to measure the ARF-induced vibration. For analysis of the shear modulus, the Doppler variance method is utilized to visualize shear ...

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    6. Integrated Ultrasound, OCT, PA AND/OR Florescence Imaging Endoscope For Diagnosing Cancers In Gastrointestinal, Respiratory, And Urogenital Tracts

      Integrated Ultrasound, OCT, PA AND/OR Florescence Imaging Endoscope For Diagnosing Cancers In Gastrointestinal, Respiratory, And Urogenital Tracts

      A multimodality imaging system including ultrasound, optical coherence tomography (OCT), photoacoustic (PA) imaging, florescence imaging and endoscopic catheter for imaging inside the gastrointestinal tract with real-time automatic image co-registration capability, including: an ultrasound subsystem for imaging; an optical coherence tomography (OCT) subsystem for imaging, a PA microscopy or tomography subsystem for imaging and a florescence imaging subsystem for imaging. An invasive interventional imaging device is included with an instrumentality to take a tissue biopsy from a location visible on the ultrasound subsystem for imaging, on the optical coherence tomography (OCT) subsystem for imaging, photoacoustic (PA) subsystem for imaging and florescence ...

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      Mentions: UC Irvine
    7. Integrated OCT-US catheter for detection of cancer in gastrointestinal tract

      Integrated OCT-US catheter for detection of cancer in gastrointestinal tract

      Gastrointestinal tract cancer, the most common type of cancer, has a very low survival rate, especially for pancreatic cancer (five year survival rate of 5%) and bile duct cancer (five year survival rate of 12%). Here, we propose to use an integrated OCT-US catheter for cancer detection. OCT is targeted to acquire detailed information, such as dysplasia and neoplasia, for early detection of tumors. US is used for staging cancers according to the size of the primary tumor and whether or not it has invaded lymph nodes and other parts of the body. Considering the lumen size of the GI ...

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    8. Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      In this Letter, we present a trimodality imaging system and an intravascular endoscopic probe for the detection of early-stage atherosclerotic plaques. The integrated system is able to acquire optical coherence tomography (OCT), fluorescence, and ultrasound images and simultaneously display them in real time. A trimodality intravascular endoscopic probe of 1.2 mm in diameter and 7 mm in length was fabricated based on a dual-modality optical probe that integrates OCT and fluorescence imaging functions and a miniature ultrasound transducer. The probe is capable of rotating at up to 600 rpm. Ex vivo images from rabbit aorta and human coronary arteries ...

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    9. Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer

      Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer

      We designed and developed a confocal acoustic radiation force optical coherence elastography system. A ring ultrasound transducer was used to achieve reflection mode excitation and generate an oscillating acoustic radiation force in order to generate displacements within the tissue, which were detected using the phase-resolved optical coherence elastography method. Both phantom and human tissue tests indicate that this system is able to sense the stiffness difference of samples and quantitatively map the elastic property of materials. Our confocal setup promises a great potential for point by point elastic imaging in vivo and differentiation of diseased tissues from normal tissue.

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    10. Resonant Acoustic Radiation Force Optical Coherence Elastography

      Resonant Acoustic Radiation Force Optical Coherence Elastography

      We reported on the development of a resonant acoustic radiation force optical coherence elastography (ARF-OCE) technique that uses mechanical resonant frequency to characterize and identify tissues of different types. The results of resonant ARF-OCE imaging of a post-mortem human coronary artery with atherosclerosis demonstrate the potential of resonant ARF-OCE as a non-invasive method for imaging and characterizing vulnerable plaques. Knowledge of tissue mechanical properties provides valuable medical information in disease diagnosis and prognosis. There is a close correlation between tissue elasticity and pathology. For example, in atherosclerosis, measurement of tissue biomechanical properties has the potential to differentiate between various plaque ...

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    11. Integrated IVUS-OCT for Real-Time Imaging of Coronary Atherosclerosis

      Integrated IVUS-OCT for Real-Time Imaging of Coronary Atherosclerosis

      Accurate assessment of atherosclerotic plaque characteristics and the subsequent tailoring of optimal therapy holds great promise for preventing acute coronary syndromes (ACS) and life-threatening sequelae 1 . Combined use of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) was proposed as a potential method for accurate assessment of plaque characteristics and vulnerability ( 2 , ). However, significant challenges remain in trying to adapt an integrated OCT-IVUS system for clinical applications. We report here a fully integrated intracoronary OCT-IVUS imaging technique to visualize atherosclerotic plaque in living animals and human coronary arteries from cadavers with high resolution and deep penetration capability simultaneously.

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    12. Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display

      Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display

      Combined use of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) holds the potential of combining the strengths of both imaging modalities and improving the diagnostic accuracy of atherosclerotic plaque vulnerability. In this manuscript, we reported a co-registered intracoronary OCT-IVUS system and catheter with real-time imaging and polar-coordinate displaying capability, well-suited for clinical utilization in guiding interventional cardiologists. With an eventual goal of clinical use in humans, this novel catheter design and modified software are poised to strengthen the ability to diagnose vulnerable plaques in patients in real-time. We upgraded our old designs in the following aspects. 1) This novel ...

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    13. Miniature optical coherence tomography-ultrasound probe for automatically coregistered three-dimensional intracoronary imaging with real-time display

      Miniature optical coherence tomography-ultrasound probe for automatically coregistered three-dimensional intracoronary imaging with real-time display

      We have developed a novel miniature integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5-mm-long rigid part and 0.9-mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding of interventional procedures. By placing the OCT ball lens and IVUS transducer back-to-back at the same axial position, this probe can provide automatically coregistered, coaxial OCT-IVUS imaging. To demonstrate its real-time capability, three-dimensional OCT-IVUS imaging of a pig’s coronary artery displaying in polar coordinates, as well as images of three major types of atherosclerotic plaques in human cadaver coronary segments, were obtained using this ...

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    14. A 2.5-mm diameter probe for photoacoustic and ultrasonic endoscopy

      A 2.5-mm diameter probe for photoacoustic and ultrasonic endoscopy

      We have created a 2.5-mm outer diameter integrated photo-acoustic and ultrasonic mini-probe which can be inserted into a standard video endoscope’s instrument channel. A small-diameter focused ultrasonic transducer made of PMN-PT provides adequate signal sensitivity, and enables miniaturization of the probe. Additionally, this new endoscopic probe utilizes the same scanning mirror and micromotor-based built-in actuator described in our previous reports; however, the length of the rigid distal section of the new probe has been further reduced to ~35 mm. This paper describes the technical details of the mini-probe and presents experimental results that both quantify the imaging performance ...

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    15. Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) catheter for characterization of atherosclerotic plaques in vivo

      Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) catheter for characterization of atherosclerotic plaques in vivo

      A miniature integrated intravascular optical coherence tomography (OCT) - ultrasound (US) catheter for real-time imaging of atherosclerotic plaques has been developed, providing high resolution and deep tissue penetration at the same time. This catheter, with an outer diameter of 1.18mm, is suitable for imaging in human coronary arteries. The first in vivo 3D imaging of atherosclerotic microstructure in a rabbit abdominal aorta obtained by an integrated OCT-US catheter is presented. In addition, in vitro imaging of cadaver coronary arteries were conducted to demonstrate the imaging capabilities of this integrated catheter to classify different atherosclerotic plaque types.

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    16. Novel combined miniature optical coherence tomography ultrasound probe for in vivo intravascular imaging

      Novel combined miniature optical coherence tomography ultrasound probe for in vivo intravascular imaging

      We have developed a miniature integrated optical coherence tomography (OCT) ultrasound (US) probing system for intravascular imaging applications. In the OCT probe, the light coming out of a single mode fiber is focused by a gradient-index lens and then reflected by a right-angle prism from the side of the probe into the sample. It was combined with a 35 MHz PMN-PT side-viewing ultrasound transducer to obtain the ultrasound image as well. The OCT and ultrasound probes were integrated as a single probe to obtain OCT and ultrasound images simultaneously. The integrated probe has an outer diameter of 0.69 mm ...

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    17. Integrated optical coherence tomography - ultrasound system and miniaturized probes for intravascular imaging

      Integrated optical coherence tomography - ultrasound system and miniaturized probes for intravascular imaging

      We report on the development of a multimodal optical coherence tomography (OCT) - ultrasound (US) system and miniaturized OCT-US probe for intravascular imaging. Both OCT optical components and a US transducer were integrated into a single probe, enabling both OCT and US imaging at the same time. A miniaturized OCT-US probe using a single element transducer was designed with a maximum outer diameter of 0.8 mm, which is suitable for in vivo intravascular imaging. The integrated OCT-US imaging system adopted a two-channel data acquisition card to digitize both OCT and US signals. Simultaneous OCT and US data processing and image ...

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    18. Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine

      Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine
      Feature Of The Week 1/30/11: Multimodality imaging with OCT is a hot topic in general and at Photonics West in particular. This week’s “Feature Of The Week” is about integrated OCT and IVUS imaging. Below is a summary of work by researchers from the Viterbi School of Engineering at the University of Southern California and the Beckman Laser Institute and Department of Biomedical Engineering at the University of California, Irvine.The USC and UC Irvine researchers developed a dual-mode biomedical imaging probe utilizing intravascular ultrasound (IVUS) and optical coherence tomography (OCT). It consists of an OCT probe ...
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    19. A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications

      A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications
      We have developed a dual-modality biomedical imaging probe utilizing intravascular ultrasound (IVUS) and optical coherence tomography (OCT). It consists of an OCT probe, a miniature ultrasonic transducer and a fixed mirror. The mirror was mounted at the head of the hybrid probe 45° relative to the light and the ultrasound beams to change their propagation directions. The probe was designed to be able to cover a larger area in blood vessel by IVUS and then visualize a specific point at a much finer image resolution using OCT. To demonstrate both its feasibility and potential clinical applications, we used this ultrasound-guide ...
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    20. High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe

      High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe
      We report an integrated ultrasound (US) and optical coherence tomography (OCT) probe and system for intravascular imaging. The dual-function probe is based on a 50 MHz focused ring US transducer, with a centric hole for mounting OCT probe. The coaxial US and light beams are steered by a 45° mirror to enable coregistered US/OCT imaging simultaneously. Lateral resolution of US is improved due to focused ultrasonic beam. Mirror effects on US were investigated and in vitro imaging of a rabbit aorta has been carried out. The combined US-OCT system demonstrated high resolution in visualizing superficial arterial structures while retaining ...
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    21. High-Resolution Photoacoustic Imaging of Ocular Tissues

      High-Resolution Photoacoustic Imaging of Ocular Tissues
      Abstract: Optical coherence tomography (OCT) and ultrasound (US) are methods widely used for diagnostic imaging of the eye. These techniques detect discontinuities in optical refractive index and acoustic impedance, respectively. Because these both relate to variations in tissue density or composition, OCT and US images share a qualitatively similar appearance. In photoacoustic imaging (PAI), short light pulses are directed at tissues, pressure is generated due to a rapid energy deposition in the tissue volume and thermoelastic expansion results in generation of broadband US. PAI thus depicts optical absorption, which is independent of the tissue characteristics imaged by OCT or US ...
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    22. Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) imaging system

      Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) imaging system
      Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are considered two complementary imaging techniques in the detection and diagnosis of atherosclerosis. OCT permits visualization of micron-scale features of atherosclerosis plaque, and IVUS offers full imaging depth of vessel wall. Under the guidance of IVUS, minimal amount of flushing agent will be needed to obtain OCT imaging of the interested area. We report on a dual-modality optical coherence tomography (OCT) - ultrasound (US) system for intravascular imaging. To the best of our knowledge, we have developed the first integrated OCT-US probe that combines OCT optical components with an ultrasound transducer. The OCT ...
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    23. Integrated intravascular optical coherence tomography ultrasound imaging system

      Integrated intravascular optical coherence tomography ultrasound imaging system
      We report on a dual-modality optical coherence tomography (OCT) ultrasound (US) system for intravascular imaging. To the best of our knowledge, we have developed the first integrated OCT-US probe that combines OCT optical components with an US transducer. The OCT optical components mainly consist of a single-mode fiber, a gradient index lens for light-beam focusing, and a right-angled prism for reflecting light into biological tissue. A 40-MHz piezoelectric transducer (PZT-5H) side-viewing US transducer was fabricated to obtain the US image. These components were integrated into a single probe, enabling both OCT and US imaging at the same time. In vitro ...
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    24. Photoacoustic ophthalmoscopy for in vivo retinal imaging

      Photoacoustic ophthalmoscopy for in vivo retinal imaging

      We have developed a non-invasive photoacousticophthalmoscopy (PAOM) for in vivo retinal imaging. PAOM detects the photoacoustic signal induced by pulsed laser light shined onto the retina. Byusing a stationary ultrasonic transducer in contact with the eyelids and scanning only the laser light across the retina, PAOM provides volumetricimaging of the retinal micro-vasculature and retinal pigment epithelium at ahigh speed. For B-scan frames containing 256 A-lines, the current PAOMhas a frame rate of 93 Hz, which is comparable with state-of-the-artcommercial spectral-domain optical coherence tomography (SD-OCT). Byintegrating PAOM with SD-OCT, we further achieved OCT-guided PAOM,which can provide multi-modal retinal imaging simultaneously ...

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    1-24 of 24
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    Photoacoustic ophthalmoscopy for in vivo retinal imaging Integrated intravascular optical coherence tomography ultrasound imaging system Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) imaging system High-Resolution Photoacoustic Imaging of Ocular Tissues High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine Integrated optical coherence tomography - ultrasound system and miniaturized probes for intravascular imaging Novel combined miniature optical coherence tomography ultrasound probe for in vivo intravascular imaging Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display Quantification of biomechanical properties of human corneal scar using acoustic radiation force optical coherence elastography Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb