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Jiawen Li,
Xiang Li,
Joseph Jing,
Dilbahar Mohar,
Aidan Raney, Sari Mahon,
Matthew Brenner,
Qifa Zhou,
Pranav Patel,
K Kirk Shung,
Zhongping Chen
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ABSTRACT: 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.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:3175-8.
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ABSTRACT: Optical coherence tomography (OCT) is a nondestructive imaging technique offering high temporal and spatial resolution, which makes it a natural choice for assessing tissue mechanical properties. We have developed methods to mechanically analyze the compliance of the rabbit trachea in vivo using tissue deformations induced by tidal breathing, offering a unique tool to assess the behavior of the airways during their normal function. Four-hundred images were acquired during tidal breathing with a custom-built endoscopic OCT system. The surface of the tissue was extracted from a set of these images via image processing algorithms, filtered with a bandpass filter set at respiration frequency to remove cardiac and probe motion, and compared to ventilatory pressure to calculate wall compliance. These algorithms were tested on elastic phantoms to establish reliability and reproducibility. The mean tracheal wall compliance (in five animals) was 1.3±0.3×10(-5) (mm Pa)(-1). Unlike previous work evaluating airway mechanics, this new method is applicable in vivo, noncontact, and loads the trachea in a physiological manner. The technique may have applications in assessing airway mechanics in diseases such as asthma that are characterized by significant airway remodeling.
Journal of Biomedical Optics 10/2011; 16(10):106011. · 3.16 Impact Factor
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Jiechen Yin,
Xiang Li,
Joe Jing,
Jiawen Li,
David Mukai, Sari Mahon,
Ahmad Edris,
Khiet Hoang,
K Kirk Shung,
Matthew Brenner,
Jagat Narula,
Qifa Zhou,
Zhongping Chen
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ABSTRACT: 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 which, to our knowledge, is the smallest integrated OCT-US probe reported. Fast data acquisition and processing was implemented for real-time imaging. In vitro OCT and US images of human coronary artery with pathology, as well as in vivo images of normal rabbit abdominal aorta, were obtained using the integrated OCT-US probe to demonstrate its capability.
Journal of Biomedical Optics 06/2011; 16(6):060505. · 3.16 Impact Factor
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Sang-Won Lee,
Andrew E Heidary,
David Yoon,
David Mukai,
Tirunelveli Ramalingam, Sari Mahon,
Jiechen Yin,
Joseph Jing,
Gangjun Liu,
Zhongping Chen,
Matthew Brenner
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ABSTRACT: Smoke inhalation injury is frequently accompanied by cyanide poisoning that may result in substantial morbidity and mortality, and methods are needed to quantitatively determine extent of airway injury. We utilized a 3-D endoscopic frequency-domain optical coherence tomography (FD-OCT) constructed with a swept-source laser to investigate morphological airway changes following smoke and cyanide exposure in rabbits. The thickness of the mucosal area between the epithelium and cartilage in the airway was measured and quantified. 3-D endoscopic FD-OCT was able to detect significant increases in the thickness of the tracheal walls of the rabbit beginning almost immediately after smoke inhalation injuries which were similar to those with combined smoke and cyanide poisoning.
Biomedical Optics Express 01/2011; 2(2):243-54. · 2.33 Impact Factor
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ABSTRACT: Concentrated aqueous solutions of hydroxocobalamin (OHCob) are administered intravenously for cyanide poisoning victims, many of whom also have concurrent smoke inhalation. Because of its intense light absorbance in visible wavelengths (absorption peak at 532 nm), we investigate potential interference effects of OHCob on total hemoglobin concentration (tHb), carboxyhemoglobin (COHb), methemoglobin (MetHb), and oxyhemoglobin (Hb-O2) cooximetry measurement values in blood.
In vivo cooximetry measurements were conducted with 3 specific pathogen-free white New Zealand rabbits (3.80+/-0.21 kg) during the intravenous infusion of OHCob (625 mg during a 100-minute period). Resultant changes in tHb, Hb-O2, COHb, and MetHb values were measured and correlated with respect to estimated in vivo OHCob concentrations. In vitro measurements were conducted with rabbit blood to confirm in vivo measurements.
The introduction of OHCob clearly interfered with the cooximetry measurements of each of the hemoglobin component fractions in whole blood and resulted in altered measurement values from the baseline values. The presence of OHCob in blood interferes with cooximetry measurements of COHb, MetHb, and Hb-O2. The increase in measured COHb fraction with increasing concentrations of OHCob was most notable.
The presence of OHCob in blood interferes with cooximetry measurements of COHb, MetHb, and Hb-O2. These effects need to be considered during OHCob treatment of cyanide poisoning, particularly in smoke inhalation victims with potential for concurrent carbon monoxide exposure, because it may lead to potentially erroneous reported COHb levels.
Annals of emergency medicine 07/2007; 49(6):802-5. · 4.23 Impact Factor
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Matthew Brenner,
Kelly Kreuter,
Johnny Ju, Sari Mahon,
Lillian Tseng,
David Mukai,
Tanya Burney,
Shuguang Guo,
Jianping Su,
Andrew Tran,
Andriy Batchinsky,
Leopoldo C Cancio,
Navneet Narula,
Zhongping Chen
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ABSTRACT: Smoke inhalation injury causes acute airway injury that may result in airway compromise with significant morbidity and mortality. We investigate the ability of high resolution endobronchial optical coherence tomography (OCT) to obtain real-time images for quantitatively assessing regional differences between upper tracheal versus lower tracheal and bronchial airway injury responses to smoke inhalation in vivo using a prototype spectral domain (SLD)-OCT system we constructed, and flexible fiber optic probes. 33 New Zealand White rabbits are intubated and mechanically ventilated. The treatment groups are exposed to inhaled smoke. The OCT probe is introduced through the endotracheal tube and maintained in place for 5 to 6 h. Images of airway mucosa and submucosa are obtained at baseline and at specified intervals postexposure. Starting within less than 15 min after smoke inhalation, there is significant airway thickening in the smoke-exposed animals. This is maintained over 5 h of imaging studies. The lower tracheal airway changes, correlating closely with carboxyhemoglobin levels, are much greater than upper tracheal changes. Significant differences are seen in lower trachea and bronchi after acute smoke inhalation compared to upper trachea as measured in vivo by minimally invasive OCT. OCT is capable of quantitatively detecting regional changes in airway swelling following inhalation injury.
Journal of Biomedical Optics 13(3):034001. · 3.16 Impact Factor
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Matthew Brenner,
Kelly Kreuter,
David Mukai,
Tanya Burney,
Shuguang Guo,
Jianping Su, Sari Mahon,
Andrew Tran,
Lillian Tseng,
Johnny Ju,
Zhongping Chen
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ABSTRACT: Optical coherence tomography (OCT) is a micron scale high-resolution optical technology that can provide real-time in vivo images noninvasively. The ability to detect airway mucosal and submucosal injury rapidly will be valuable for a range of pulmonary applications including assessment of acute inhalation smoke and burn injury. OCT has the potential ability to monitor the progression of airway injury changes including edema, hyperemia, and swelling, which are critical clinical components of smoke-inhalation injury. New Zealand white male rabbits exposed to cold smoke from standardized unbleached burned cotton administered during ventilation were monitored for 6 h using a 1.8-mm diameter flexible fiberoptic longitudinal probe that was inserted through the endotracheal tube. The thickness of the epithelial, mucosal, and submucosal layers of the rabbit trachea to the tracheal cartilage was measured using a prototype superluminescent diode OCT system we constructed. OCT was able to detect significant smoke-injury-induced increases in the thickness of the tracheal walls of the rabbit beginning very shortly after smoke administration. Airway wall thickness increased to an average of 120% (+/-33%) of baseline values by 5 h following exposure. OCT is capable of providing real-time, noninvasive images of airway injury changes following smoke exposure. These studies suggest that OCT may have the ability to provide information on potential early indicators of impending smoke-inhalation-induced airway compromise.
Journal of Biomedical Optics 12(5):051701. · 3.16 Impact Factor
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Khiet C Hoang,
Ahmad Edris,
Jianping Su,
David S Mukai, Sari Mahon,
Artiom D Petrov,
Morton Kern,
Chowdhury Ashan,
Zhongping Chen,
Bruce J Tromberg,
Jagat Narula,
Matthew Brenner
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ABSTRACT: Optical coherence tomography (OCT) is a catheter-based imaging technology with powerful resolution capable of identifying vulnerable plaques and guiding coronary intervention. However, a significant limitation of intravascular OCT imaging is its attenuation by blood. We propose that the use of an oxygen-carrying blood substitute could potentially optimize OCT image quality. Surgical isolation of the descending thoracic aorta of six rabbits is performed, followed by intravascular OCT imaging of the abdominal aorta. Perfluorodecalin (PFD) is oxygenated using a bubble-through technique with 100% oxygen. OCT imaging is performed and compared using three different flushing modalities: PFD; saline; and blood. OCT imaging of the rabbit abdominal aorta is successful in all of the subjects. In each of the six studied subjects, flushing with PFD consistently provides dramatically better imaging of the vessel wall tissue structures. OCT image quality is highly dependent on the ability of the flushing modality to remove blood from the imaging field. From this proof-of-concept study, we demonstrate that endovascular flushing with an oxygen-carrying blood substitute (PFD) is optically superior to saline flushing for intravascular imaging.
Journal of Biomedical Optics 14(3):034028. · 3.16 Impact Factor
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ABSTRACT: We report on the feasibility of rapid, high-resolution, 3-D swept-source optical coherence tomography (SSOCT) to detect early airway injury changes following smoke inhalation exposure in a rabbit model. The SSOCT system obtains 3-D helical scanning using a microelectromechanical system motor-based endoscope. Real-time 2-D data processing and image display at the speed of 20 frames/s are achieved by adopting the technique of parallel computing. Longitudinal images are reconstructed via an image processing algorithm to remove motion artifacts caused by ventilation and pulse. Quantitative analyses of tracheal airway thickness as well as thickness distribution along tracheal circumference are also performed based on the comprehensive 3-D volumetric data.
Journal of Biomedical Optics 14(6):060503. · 3.16 Impact Factor
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ABSTRACT: Chronic mucosal and submucosal injury can lead to persistent inflammation and tissue remodeling. We hypothesized that microstructural and mechanical properties of the airway wall could be derived from multiphoton images. New Zealand White rabbits were intubated, and the tracheal epithelium gently denuded every other day for five days (three injuries). Three days following the last injury, the tracheas were excised for multiphoton imaging, mechanical compression testing, and histological analysis. Multiphoton imaging and histology confirm epithelial denudation, mucosal ulceration, subepithelial thickening, collagen deposition, immune cell infiltration, and a disrupted elastin network. Elastase removes the elastin network and relaxes the collagen network. Purified collagenase removes epithelium with subtle subepithelial changes. Young's modulus [(E) measured in kiloPascal] was significantly elevated for the scrape injured (9.0+/-3.2) trachea, and both collagenase (2.6+/-0.4) and elastase (0.8+/-0.3) treatment significantly reduced E relative to control (4.1+/-0.7). E correlates strongly with second harmonic generation (SHG) signal depth decay for enzyme-treated and control tracheas (R(2)=0.77), but not with scrape-injured tracheas. We conclude that E of subepithelial connective tissue increases on repeated epithelial wounding, due in part to changes in elastin and collagen microstructure and concentration. SHG depth decay is sensitive to changes in extracellular matrix content and correlates with bulk Young's modulus.
Journal of Biomedical Optics 15(1):015004. · 3.16 Impact Factor
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ABSTRACT: The purpose of this study was to develop a dynamic tunable focal distance graded-refractive-index lens rod-based high-speed 3-D swept-source (SS) optical coherence tomography (OCT) endoscopic system and demonstrate real-time in vivo, high-resolution (10-microm) imaging of pleural-based malignancies in an animal model. The GRIN lens-based 3-D SS OCT system, which images at 39 fps with 512 A-lines per frame, was able to capture images of and detect abnormalities during thoracoscopy in the thoracic cavity, including the pleura, chest wall, pericardium, and the lungs. The abnormalities were confirmed by histological evaluation and compared to OCT findings. The dynamic tunable focal distance range and rapid speed of the probe and SS prototype OCT system enabled this first-reported application of in vivo 3-D thoracoscopic imaging of pleural-based malignancies. The imaging probe of the system was found to be easily adaptable to various sites within the thoracic cavity and can be readily adapted to other sites, including rigid airway endoscopic examinations.
Journal of Biomedical Optics 14(6):064045. · 3.16 Impact Factor
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ABSTRACT: We demonstrate noninvasive near-infrared diffuse optical spectroscopy (DOS) measurements of tissue hemoglobin contents that can track progressive reductions in central blood volume in human volunteers. Measurements of mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV), and cardiac output (Q) are obtained in ten healthy human subjects during baseline supine rest and exposure to progressive reductions of central blood volume produced by application of lower body negative pressure (LBNP). Simultaneous quantitative noninvasive measurements of tissue oxyhemoglobin (OHb), deoxyhemoglobin (RHb), total hemoglobin concentration (THb), and tissue hemoglobin oxygen saturation (S(t)O(2)) are performed throughout LBNP application using broadband DOS. As progressively increasing amounts of LBNP are applied, HR increases, and MAP, SV, and Q decrease (p<0.001). OHb, S(t)O(2), and THb decrease (p<0.001) in correlation with progressive increases in LBNP, while tissue RHb remained relatively constant (p=0.378). The average fractional changes from baseline values in DOS OHb (fOHb) correlate closely with independently measured changes in SV (r(2)=0.95) and Q (r(2)=0.98) during LBNP. Quantitative noninvasive broadband DOS measurements of tissue hemoglobin parameters of peripheral perfusion are capable of detecting progressive reductions in central blood volume, and appear to be sensitive markers of early hypoperfusion associated with hemorrhage as simulated by LBNP.
Journal of Biomedical Optics 13(6):064027. · 3.16 Impact Factor
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ABSTRACT: Hemoglobin-based oxygen carriers (HBOCs) are solutions of cell-free hemoglobin (Hb) that have been developed for replacement or augmentation of blood transfusion. It is important to monitor in vivo tissue hemoglobin content, total tissue hemoglobin [THb], oxy- and deoxy-hemoglobin concentrations ([OHb], [RHb]), and tissue oxygen saturation (S(t)O(2)=[OHb][THb]x100%) to evaluate effectiveness of HBOC transfusion. We designed and constructed a broadband diffuse optical spectroscopy (DOS) prototype system to measure bulk tissue absorption and scattering spectra between 650 and 1000 nm capable of accurately determining these tissue hemoglobin component concentrations in vivo. Our purpose was to assess the feasibility of using DOS to optically monitor tissue [OHb], [RHb], S(t)O(2), and total tissue hemoglobin concentration ([THb]=[OHb]+[RHb]) during HBOC infusion using a rabbit hypovolemic shock model. The DOS prototype probe was placed on the shaved inner thigh muscle of the hind leg to assess concentrations of [OHb], [RHb], [THb], as well as S(t)O(2). Hemorrhagic shock was induced in intubated New Zealand white rabbits (N=6) by withdrawing blood via a femoral arterial line to 20% blood loss (10-15 cckg). Hemoglobin glutamer-200 (Hb-200) 1:1 volume resuscitation was administered following the hemorrhage. These values were compared against traditional invasive measurements, serum hemoglobin concentration (sHGB), systemic blood pressure, heart rate, and blood gases. DOS revealed increases of [THb], [OHb], and tissue hemoglobin oxygen saturation after Hb-200 infusion, while blood total hemoglobin values continued did not increase; we speculate, due to hyperosmolality induced hemodilution. DOS enables noninvasive in vivo monitoring of tissue hemoglobin and oxygenation parameters during shock and volume expansion with HBOC and potentially enables the assessment of efficacy of resuscitation efforts using artificial blood substitutes.
Journal of Biomedical Optics 14(4):044027. · 3.16 Impact Factor
