Zhongping Chen

Wenzhou University, Yung-chia, Zhejiang Sheng, China

Are you Zhongping Chen?

Claim your profile

Publications (374)691.93 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives/hypothesis: To evaluate for the first time the feasibility and methodology of long-range Fourier domain optical coherence tomography (LR-OCT) imaging of the internal nasal valve (INV) area in healthy individuals. Study design: Prospective individual cohort study. Methods: For 16 individuals, OCT was performed in each nare. The angle and the cross-sectional area of the INV were measured. OCT images were compared to corresponding digital pictures recorded with a flexible endoscope. Results: INV angle measured by OCT was found to be 18.3° ± 3.1° (mean ± standard deviation). The cross-sectional area was 0.65 ± 0.23 cm(2) . The INV angle measured by endoscopy was 18.8° ± 6.9°. There was no statistically significant difference between endoscopy and OCT concerning the mean INV angle (P = .778), but there was a significant difference in test precision (coefficient of variance 50% vs. 15%; P < .001). Conclusions: LR-OCT proved to be a fast and easily performed method. OCT could accurately quantify the INV area. The values of the angle and the cross-sectional area of the INV were reproducible and correlated well with the data seen with other methods. Changes in size could be reliably delineated. Endoscopy showed similar values but was significantly less precise. Level of evidence: 2b. Laryngoscope, 2015.
    The Laryngoscope 11/2015; DOI:10.1002/lary.25785 · 2.14 Impact Factor
  • Source
    Lv Ming Zeng · Zhonglie Piao · Shenghai Huang · Wangcun Jia · Zhongping Chen ·
    [Show abstract] [Hide abstract]
    ABSTRACT: We have developed laser-diode-based optical-resolution photoacoustic microscopy (LD-OR-PAM) of superficial microvasculature which has the desirable properties of being compact, low-cost, and label-free. A 300-mW visible pulsed laser diode was operated at 405 ± 5 nm wavelength with a pulse energy as low as 52 nJ. By using a 3.6 MHz ultrasound transducer, the system was tested on carbon fibers with a lateral resolution of 0.95 µm and an SNR of 38 dB. The subcutaneous microvasculature on a mouse back was imaged without an exogenous contrast agent which demonstrates the potential of the proposed prototype for skin chromophores. Our eventual goal is to offer a practical and affordable multi-wavelength functional LD-OR-PAM instrument suitable for clinical applications.
    Optics Express 11/2015; 23(24):31026-31033. DOI:10.1364/OE.23.031026 · 3.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Lipid deposition inside the arterial wall is a hallmark of plaque vulnerability. Based on overtone absorption of C-H bonds, intravascular photoacoustic (IVPA) catheter is a promising technology for quantifying the amount of lipid and its spatial distribution inside the arterial wall. Thus far, the clinical translation of IVPA technology is limited by its slow imaging speed due to lack of a high-pulse-energy high-repetition-rate laser source for lipid-specific first overtone excitation at 1.7 μm. Here, we demonstrate a potassium titanyl phosphate (KTP)-based optical parametric oscillator with output pulse energy up to 2 mJ at a wavelength of 1724 nm and with a repetition rate of 500 Hz. Using this laser and a ring-shape transducer, IVPA imaging at speed of 1 frame per sec was demonstrated. Performance of the IVPA imaging system's resolution, sensitivity, and specificity were characterized by carbon fiber and a lipid-mimicking phantom. The clinical utility of this technology was further evaluated ex vivo in an excised atherosclerotic human femoral artery with comparison to histology.
    Biomedical Optics Express 11/2015; 6(11):4557. DOI:10.1364/BOE.6.004557 · 3.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intravascular photoacoustic imaging at 1.7 μm spectral band has shown promising capabilities for lipid-rich vulnerable atherosclerotic plaque detection. In this work, we report a high speed catheter-based integrated intravascular photoacoustic/intravascular ultrasound (IVPA/IVUS) imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A lipid-mimicking phantom and atherosclerotic rabbit abdominal aorta were imaged at 1 frame per second, which is two orders of magnitude faster than previously reported in IVPA imaging with the same wavelength. Clear photoacoustic signals by the absorption of lipid rich deposition demonstrated the ability of the system for high speed vulnerable atherosclerotic plaques detection.
    Applied Physics Letters 08/2015; 107(8):083701. DOI:10.1063/1.4929584 · 3.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The upper airway is a complex and intricate system responsible for respiration, phonation, and deglutition. Obstruction of the upper airways afflicts an estimated 12–18 million Americans. Pharyngeal size and shape are important factors in the pathogenesis of airway obstructions. In addition, nocturnal loss in pharyngeal muscular tone combined with high pharyngeal resistance can lead to collapse of the airway and periodic partial or complete upper airway obstruction. Anatomical optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images of the airway lumen without the use of ionizing radiation. In this chapter we describe the methods behind endoscopic OCT imaging and processing to generate full three dimensional anatomical models of the human airway which can be used in conjunction with numerical simulation methods to assess areas of airway obstruction. Combining this structural information with flow dynamic simulations, we can better estimate the site and causes of airway obstruction and better select and design surgery for patients with obstructive sleep apnea. © Springer-Verlag Berlin Heidelberg 2008 and Springer International Publishing Switzerland 2015.
    Optical Coherence Tomography: Technology and Applications, Second edition edited by Wolfgang Drexler, James G. Fujimoto, 08/2015: chapter 75: pages 2245-2262; Springer., ISBN: 978-3-319-06418-5 (Print), 978-3-319-06419-2 (Online)
  • [Show abstract] [Hide abstract]
    ABSTRACT: Subglottic edema and acquired subglottic stenosis are potentially airway-compromising sequelae in neonates following endotracheal intubation. At present, no imaging modality is capable of in vivo diagnosis of subepithelial airway wall pathology as signs of intubation-related injury. To use Fourier domain long-range optical coherence tomography (LR-OCT) to acquire micrometer-resolution images of the airway wall of intubated neonates in a neonatal intensive care unit (NICU) setting and to analyze images for histopathology and airway wall thickness. LR-OCT of the neonatal laryngotracheal airway was performed a total of 94 times on 72 subjects (age 1-175 days, total intubation 1-104 days). LR-OCT images of the airway wall were analyzed in MATLAB. Medical records were reviewed retrospectively for extubation outcome. Backwards stepwise regression analysis demonstrated a statistically significant association between log(duration of intubation) and both laryngeal (p<0.001; multiple r2=0.44) and subglottic (p<0.001; multiple r2=0.55) airway wall thickness. Subjects with positive histopathology on LR-OCT images had a higher likelihood of extubation failure (odds ratio 5.9, p=0.007). Longer intubation time was found to be significantly associated with extubation failure. LR-OCT allows for high-resolution evaluation and measurement of the airway wall in intubated neonates. Our data demonstrate a positive correlation between laryngeal and subglottic wall thickness and duration of intubation, suggestive of progressive soft tissue injury. LR-OCT may ultimately aid in the early diagnosis of post-intubation subglottic injury and help reduce the incidences of failed extubation due to subglottic edema or acquired subglottic stenosis in neonates. Clinical trial registration available at www.clinicaltrials.gov, ID NCT00544427.
    American Journal of Respiratory and Critical Care Medicine 07/2015; DOI:10.1164/rccm.201501-0053OC · 13.00 Impact Factor
  • Bryan T Lemieux · Jason J Chen · Joseph Jing · Zhongping Chen · Brian J F Wong ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Measuring ciliary beat frequency (CBF) is a technical challenge and difficult to perform in vivo. Doppler optical coherence tomography (D-OCT) is a mesoscopic noncontact imaging modality that provides high-resolution tomographic images and detects micromotion simultaneously in living tissues. In this work we used D-OCT to measure CBF in ex vivo tissue as the first step toward translating this technology to clinical use. Fresh ex vivo samples of rabbit tracheal mucosa were imaged using both D-OCT and phase-contrast microscopy (n = 5). The D-OCT system was designed and built to specification in our lab (1310-nm swept source vertical-cavity surface-emitting laser [VCSEL], 6-μm axial resolution). The samples were placed in culture and incubated at 37°C. A fast Fourier transform was performed on the D-OCT signal recorded on the surface of the samples to gauge CBF. High-speed digital video of the epithelium recorded via phase-contrast microscopy was analyzed to confirm the CBF measurements. The D-OCT system detected Doppler signal at the epithelial layer of ex vivo rabbit tracheal samples suggestive of ciliary motion. CBF was measured at 9.36 ± 1.22 Hz using D-OCT and 9.08 ± 0.48 Hz using phase-contrast microscopy. No significant differences were found between the 2 methods (p > 0.05). D-OCT allows for the quantitative measurement of CBF without the need to resolve individual cilia. Furthermore, D-OCT technology can be incorporated into endoscopic platforms that allow clinicians to readily measure CBF in the office and provide a direct measurement of mucosal health. © 2015 ARS-AAOA, LLC.
    International Forum of Allergy and Rhinology 07/2015; DOI:10.1002/alr.21582 · 2.37 Impact Factor
  • Source
    Shenghai Huang · Zhonglie Piao · Jiang Zhu · Fan Lu · Zhongping Chen ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases.
    Journal of Biomedical Optics 07/2015; 20(7):76003. DOI:10.1117/1.JBO.20.7.076003 · 2.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 wave propagation instead of Doppler OCT method, and the propagation velocity of the shear wave is measured at different depths of one location with the M scan. In order to quantify shear modulus beyond the OCT imaging depth, we move ARF to a deeper layer at a known step and measure the time delay of the shear wave propagating to the same OCT imaging depth. We also quantitatively map the shear modulus of a cross-section in a tissue-equivalent phantom after employing the B scan.
    Optics Letters 05/2015; 40(9):2099-102. DOI:10.1364/OL.40.002099 · 3.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An increasing number of integrated optical and acoustic intravascular imaging systems have been developed and hold great promise for accurately diagnosing vulnerable plaques and guiding atherosclerosis treatment. However, in any intravascular environment, the vascular lumen is filled with blood, a high-scattering source for optical and high-frequency ultrasound signals. Blood must be flushed away to provide clearer images. To our knowledge, no research has been performed to find the ideal flushing agent for combined optical and acoustic imaging techniques. We selected three solutions as potential flushing agents for their image-enhancing effects: mannitol, dextran, and iohexol. Testing of these flushing agents was performed in a closed-loop circulation model and in vivo on rabbits. We found that a high concentration of dextran was the most useful for simultaneous intravascular ultrasound and optical coherence tomography imaging.
    Journal of Biomedical Optics 05/2015; 20(5):56005. DOI:10.1117/1.JBO.20.5.056005 · 2.86 Impact Factor

  • IEEE Journal of Selected Topics in Quantum Electronics 01/2015; DOI:10.1109/JSTQE.2015.2493961 · 2.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 showed that this combined system is capable of providing high resolution, deep penetration depth and specific molecular fluorescence contrast simultaneously.
    Optics Letters 12/2014; 39(23):6652-5. DOI:10.1364/OL.39.006652 · 3.29 Impact Factor
  • Source

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Acquired subglottic stenosis (SGS) most commonly results from prolonged endotracheal intubation and is a diagnostic challenge in the intubated child. At present, no imaging modality allows for in vivo characterization of subglottic microanatomy to identify early signs of acquired SGS while the child remains intubated. Fourier domain optical coherence tomography (FD-OCT) is a minimally invasive, light-based imaging modality which provides high resolution, three dimensional (3D) cross-sectional images of biological tissue. We used long-range FD-OCT to image the subglottis in intubated pediatric patients undergoing minor head and neck surgical procedures in the operating room. Methods: A long-range FD-OCT system and rotary optical probes (1.2mm and 0.7mm outer diameters) were constructed. Forty-six pediatric patients (ages 2-16 years) undergoing minor upper airway surgery (e.g., tonsillectomy and adenoidectomy) were selected for intraoperative, trans-endotracheal tube FD-OCT of the subglottis. Images were analyzed for anatomical landmarks and subepithelial histology. Volumetric image sets were rendered into virtual 3D airway models in Mimics software. Results: FD-OCT was performed on 46 patients (ages 2-16 years) with no complications. Gross airway contour was visible on all 46 data sets. Twenty (43%) high-quality data sets clearly demonstrated airway anatomy (e.g., tracheal rings, cricoid and vocal folds) and layered microanatomy of the mucosa (e.g., epithelium, basement membrane and lamina propria). The remaining 26 data sets were discarded due to artifact, high signal-to-noise ratio or missing data. 3D airway models were allowed for user-controlled manipulation and multiplanar airway slicing (e.g., sagittal, coronal) for visualization of OCT data at multiple anatomic levels simultaneously. Conclusions: Long-range FD-OCT produces high-resolution, 3D volumetric images of the pediatric subglottis. This technology offers a safe and practical means for in vivo evaluation of lower airway microanatomy in intubated pediatric patients. Ultimately, FD-OCT may be applied to serial monitoring of the neonatal subglottis in long-term intubated infants at risk for acquired SGS.
    International Journal of Pediatric Otorhinolaryngology 11/2014; 79(2). DOI:10.1016/j.ijporl.2014.11.019 · 1.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: While upper airway obstruction is a common problem in the pediatric population, the first-line treatment, adenotonsillectomy, fails in up to 20% of patients. The decision to proceed to surgery is often made without quantitative anatomic guidance. We evaluated the use of a novel technique, long-range optical coherence tomography (LR-OCT), to image the upper airway of children under general anesthesia immediately before and after tonsillectomy and/or adenoidectomy. We investigated the feasibility of LR-OCT to identify both normal anatomy and sites of airway narrowing and to quantitatively compare airway lumen size in the oropharyngeal and nasopharyngeal regions pre- and post-operatively. 46 children were imaged intraoperatively with a custom-designed LR-OCT system, both before and after adenotonsillectomy. These axial LR-OCT images were both rendered into 3D airway models for qualitative analysis and manually segmented for quantitative comparison of cross-sectional area. LR-OCT images demonstrated normal anatomic structures (base of tongue, epiglottis) as well as regions of airway narrowing. Volumetric rendering of pre- and post-operative images clearly showed regions of airway collapse and post-surgical improvement in airway patency. Quantitative analysis of cross-sectional images showed an average change of 70.52mm(2) (standard deviation 47.87mm(2)) in the oropharynx after tonsillectomy and 105.58mm(2) (standard deviation 60.62mm(2)) in the nasopharynx after adenoidectomy. LR-OCT is an emerging technology that rapidly generates 3D images of the pediatric upper airway in a feasible manner. This is the first step toward development of an office-based system to image awake pediatric subjects and thus better identify loci of airway obstruction prior to surgery. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    International Journal of Pediatric Otorhinolaryngology 11/2014; 79(1). DOI:10.1016/j.ijporl.2014.11.009 · 1.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Lipid deposition inside the arterial wall is a key indicator of plaque vulnerability. An intravascular photoacoustic (IVPA) catheter is considered a promising device for quantifying the amount of lipid inside the arterial wall. Thus far, IVPA systems suffered from slow imaging speed (~50 s per frame) due to the lack of a suitable laser source for high-speed excitation of molecular overtone vibrations. Here, we report an improvement in IVPA imaging speed by two orders of magnitude, to 1.0 s per frame, enabled by a custom-built, 2-kHz master oscillator power amplifier (MOPA)-pumped, barium nitrite [Ba(NO3)2] Raman laser. This advancement narrows the gap in translating the IVPA technology to the clinical setting.
    Scientific Reports 11/2014; 4:6889. DOI:10.1038/srep06889 · 5.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives: Identifying the appropriate operation(s) for children with sleep-disordered breathing (SDB) remains a challenge, and current imaging modalities have major shortcomings. We have pioneered the use of long-range optical coherence tomography (LR-OCT) to provide real-time images of the upper airway (UA) during sleep and wakefulness. Here we present our first use of LR-OCT to image the UA of awake children. (1) Understand how LR-OCT produces high-resolution structural images by acting as an optical range-finder. (2) Recognize how LR-OCT can identify strictures and real-time collapse of the airway.
    Otolaryngology Head and Neck Surgery 09/2014; 151(1 Suppl):P133-P133. DOI:10.1177/0194599814541627a325 · 2.02 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We understand now that sleep of sufficient length and quality is required for good health. This is particularly true for infants and children, who have the added physiologic task of growth and development, as compared to their adult counterparts. Sleep-related breathing disorders (SRBDs) are common in childhood and if unrecognized and not treated can result in significant morbidity. For example, children with obstructive sleep apnea (OSA) can exhibit behavioral, mood, and learning difficulties. If left untreated, alterations in the function of the autonomic nervous system and a chronic inflammatory state result, contributing to the risk of heart disease, stroke, glucose intolerance, and hypertension in adulthood.
    IEEE Pulse 09/2014; 5(5):33-39. DOI:10.1109/MPUL.2014.2339293 · 0.96 Impact Factor

  • Journal of the American College of Cardiology 09/2014; 64(11):B111. DOI:10.1016/j.jacc.2014.07.428 · 16.50 Impact Factor

  • Journal of the American College of Cardiology 09/2014; 64(11):B108. DOI:10.1016/j.jacc.2014.07.417 · 16.50 Impact Factor

Publication Stats

6k Citations
691.93 Total Impact Points


  • 2015
    • Wenzhou University
      Yung-chia, Zhejiang Sheng, China
  • 2002-2015
    • Beckman Research Institute
      Дуарте, California, United States
  • 1996-2015
    • University of California, Irvine
      • • Department of Biomedical Engineering
      • • Beckman Laser Institute
      • • Department of Electrical Engineering and Computer Science
      Irvine, California, United States
    • US Army Armament Research, Development and Engineering Center
      Rockaway, New Jersey, United States
  • 2014
    • University of California, Los Angeles
      • Department of Bioengineering
      Los Ángeles, California, United States
  • 2008-2014
    • Pusan National University
      • Department of Cogno-Mechatronics Engineering
      Tsau-liang-hai, Busan, South Korea
  • 1999-2012
    • University of Illinois, Urbana-Champaign
      Urbana, Illinois, United States
  • 2011
    • University College London
      Londinium, England, United Kingdom
  • 2005
    • University of California, Berkeley
      • Department of Electrical Engineering and Computer Sciences
      Berkeley, MO, United States
  • 2004
    • Johns Hopkins University
      Baltimore, Maryland, United States
    • California State University
      • Department of Biomedical Engineering
      Long Beach, California, United States
  • 2003
    • Zhejiang University
      • State Key Lab of Modern Optical Instrumentation
      Hang-hsien, Zhejiang Sheng, China
    • Showa University
      Shinagawa, Tōkyō, Japan
  • 1994-1995
    • University of Massachusetts Lowell
      • Department of Chemistry
      Lowell, Massachusetts, United States