29 results on '"Guoqiang Yu"'
Search Results
2. Simultaneous measurements of tissue blood flow and oxygenation using a wearable fiber-free optical sensor
- Author
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Mingjun Zhao, Henrietta S. Bada, Chong Huang, Xuhui Liu, Yutong Gu, Yanda Cheng, Guoqiang Yu, Lei Chen, and Elie G. Abu Jawdeh
- Subjects
Paper ,Adult ,Materials science ,Biomedical Engineering ,01 natural sciences ,Imaging phantom ,wearable ,010309 optics ,Biomaterials ,Speckle pattern ,Wearable Electronic Devices ,0103 physical sciences ,blood oxygenation ,medicine ,Special Series on Wearable, Implantable, Mobile, and Remote Biomedical Optics and Photonics ,blood flow ,Humans ,Artery occlusion ,Oximetry ,CMOS sensor ,Phantoms, Imaging ,Hemodynamics ,Blood flow ,Oxygenation ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,deep tissue ,Light intensity ,Forearm ,medicine.anatomical_structure ,speckle contrast ,Biomedical engineering ,Artery - Abstract
Significance: There is an essential need to develop wearable multimodality technologies that can continuously measure both blood flow and oxygenation in deep tissues to investigate and manage various vascular/cellular diseases. Aim: To develop a wearable dual-wavelength diffuse speckle contrast flow oximetry (DSCFO) for simultaneous measurements of blood flow and oxygenation variations in deep tissues. Approach: A wearable fiber-free DSCFO probe was fabricated using 3D printing to confine two small near-infrared laser diodes and a tiny CMOS camera in positions for DSCFO measurements. The spatial diffuse speckle contrast and light intensity measurements at the two different wavelengths enable quantification of tissue blood flow and oxygenation, respectively. The DSCFO was first calibrated using tissue phantoms and then tested in adult forearms during artery cuff occlusion. Results: Phantom tests determined the largest effective source–detector distance (15 mm) and optimal camera exposure time (10 ms) and verified the accuracy of DSCFO in measuring absorption coefficient variations. The DSCFO detected substantial changes in forearm blood flow and oxygenation resulting from the artery occlusion, which meet physiological expectations and are consistent with previous study results. Conclusions: The wearable DSCFO may be used for continuous and simultaneous monitoring of blood flow and oxygenation variations in freely behaving subjects.
- Published
- 2021
3. Noncontact speckle contrast diffuse correlation tomography of blood flow distributions in tissues with arbitrary geometries
- Author
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Ahmed A. Bahrani, Lesley Wong, Mingjun Zhao, Nneamaka Agochukwu, Chong Huang, Guoqiang Yu, and Siavash Mazdeyasna
- Subjects
Materials science ,Biomedical Engineering ,Iterative reconstruction ,01 natural sciences ,Surgical Flaps ,Imaging ,030218 nuclear medicine & medical imaging ,010309 optics ,Biomaterials ,Necrosis ,03 medical and health sciences ,Speckle pattern ,0302 clinical medicine ,Image Interpretation, Computer-Assisted ,0103 physical sciences ,Humans ,Tomography, Optical ,Mastectomy ,Image restoration ,Blood flow ,Atomic and Molecular Physics, and Optics ,Diffuse optical imaging ,Electronic, Optical and Magnetic Materials ,Forearm ,Photometric stereo ,Regional Blood Flow ,Female ,Tomography ,Preclinical imaging ,Biomedical engineering - Abstract
A noncontact electron multiplying charge-coupled-device (EMCCD)-based speckle contrast diffuse correlation tomography (scDCT) technology has been recently developed in our laboratory, allowing for noninvasive three-dimensional measurement of tissue blood flow distributions. One major remaining constraint in the scDCT is the assumption of a semi-infinite tissue volume with a flat surface, which affects the image reconstruction accuracy for tissues with irregular geometries. An advanced photometric stereo technique (PST) was integrated into the scDCT system to obtain the surface geometry in real time for image reconstruction. Computer simulations demonstrated that a priori knowledge of tissue surface geometry is crucial for precisely reconstructing the anomaly with blood flow contrast. Importantly, the innovative integration design with one single-EMCCD camera for both PST and scDCT data collection obviates the need for offline alignment of sources and detectors on the tissue boundary. The in vivo imaging capability of the updated scDCT is demonstrated by imaging dynamic changes in forearm blood flow distribution during a cuff-occlusion procedure. The feasibility and safety in clinical use are evidenced by intraoperative imaging of mastectomy skin flaps and comparison with fluorescence angiography.
- Published
- 2018
4. Hybrid diffuse optical techniques for continuous hemodynamic measurement in gastrocnemius during plantar flexion exercise
- Author
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Sibu P. Saha, D. Travis Thomas, Mingjun Zhao, Brad A. Henry, Eleftherios S. Xenos, Timothy L. Uhl, Yu Shang, and Guoqiang Yu
- Subjects
Adult ,Male ,Optics and Photonics ,Biomedical Engineering ,Hemodynamics ,Gating ,Isometric exercise ,Biomaterials ,Hemoglobins ,Oxygen Consumption ,Forearm ,Research Papers: General ,Isometric Contraction ,Occlusion ,Medicine ,Plethysmograph ,Humans ,Muscle, Skeletal ,Exercise ,Oxygen saturation (medicine) ,business.industry ,Anatomy ,Blood flow ,Atomic and Molecular Physics, and Optics ,Healthy Volunteers ,Electronic, Optical and Magnetic Materials ,Oxygen ,medicine.anatomical_structure ,Lower Extremity ,Calibration ,Female ,business ,Algorithms ,Blood Flow Velocity ,Biomedical engineering - Abstract
Occlusion calibrations and gating techniques have been recently applied by our laboratory for continuous and absolute diffuse optical measurements of forearm muscle hemodynamics during handgrip exercises. The translation of these techniques from the forearm to the lower limb is the goal of this study as various diseases preferentially affect muscles in the lower extremity. This study adapted a hybrid near-infrared spectroscopy and diffuse correlation spectroscopy system with a gating algorithm to continuously quantify hemodynamic responses of medial gastrocnemius during plantar flexion exercises in 10 healthy subjects. The outcomes from optical measurement include oxy-, deoxy-, and total hemoglobin concentrations, blood oxygen saturation, and relative changes in blood flow (rBF) and oxygen consumption rate (rV˙O2). We calibrated rBF and rV˙O2 profiles with absolute baseline values of BF and V˙O2 obtained by venous and arterial occlusions, respectively. Results from this investigation were comparable to values from similar studies. Additionally, significant correlation was observed between resting local muscle BF measured by the optical technique and whole limb BF measured concurrently by a strain gauge venous plethysmography. The extensive hemodynamic and metabolic profiles during exercise will allow for future comparison studies to investigate the diagnostic value of hybrid technologies in muscles affected by disease.
- Published
- 2015
5. Noncontact diffuse optical assessment of blood flow changes in head and neck free tissue transfer flaps
- Author
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Thomas J. Gal, Yu Shang, Guoqiang Yu, Chong Huang, Amit B. Patel, Rony K. Aouad, Jeffrey P. Radabaugh, Joseph Valentino, and Yu Lin
- Subjects
Male ,medicine.medical_specialty ,Biomedical Engineering ,Anastomosis ,Free Tissue Flaps ,Biomaterials ,Vascularity ,Research Papers: General ,medicine ,Humans ,Stage (cooking) ,Aged ,Spectroscopy, Near-Infrared ,business.industry ,Head and neck cancer ,Diffuse correlation spectroscopy ,Blood flow ,Equipment Design ,Middle Aged ,medicine.disease ,Thrombosis ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Tissue transfer ,Surgery ,Head and Neck Neoplasms ,Regional Blood Flow ,Female ,medicine.symptom ,business ,Head ,Neck - Abstract
Knowledge of tissue blood flow (BF) changes after free tissue transfer may enable surgeons to predict the failure of flap thrombosis at an early stage. This study used our recently developed noncontact diffuse correlation spectroscopy to monitor dynamic BF changes in free flaps without getting in contact with the targeted tissue. Eight free flaps were elevated in patients with head and neck cancer; one of the flaps failed. Multiple BF measurements probing the transferred tissue were performed during and post the surgical operation. Postoperative BF values were normalized to the intraoperative baselines (assigning "1") for the calculation of relative BF change (rBF). The rBF changes over the seven successful flaps were 1.89 ± 0.15, 2.26 ± 0.13, and 2.43 ± 0.13 (mean ± standard error), respectively, on postoperative days 2, 4, and 7. These postoperative values were significantly higher than the intraoperative baseline values (p0.001), indicating a gradual recovery of flap vascularity after the tissue transfer. By contrast, rBF changes observed from the unsuccessful flaps were 1.14 and 1.34, respectively, on postoperative days 2 and 4, indicating less flow recovery. Measurement of BF recovery after flap anastomosis holds the potential to act early to salvage ischemic flaps.
- Published
- 2015
6. Noncontact speckle contrast diffuse correlation tomography of blood flow distributions in tissues with arbitrary geometries.
- Author
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Mazdeyasna, Siavash, Chong Huang, Mingjun Zhao, Agochukwu, Nneamaka B., Bahrani, Ahmed A., Wong, Lesley, and Guoqiang Yu
- Subjects
CHARGE coupled devices ,BLOOD flow ,PHOTOMETRIC stereo ,MASTECTOMY ,SURFACE geometry - Abstract
A noncontact electron multiplying charge-coupled-device (EMCCD)-based speckle contrast diffuse correlation tomography (scDCT) technology has been recently developed in our laboratory, allowing for noninvasive three-dimensional measurement of tissue blood flow distributions. One major remaining constraint in the scDCT is the assumption of a semi-infinite tissue volume with a flat surface, which affects the image reconstruction accuracy for tissues with irregular geometries. An advanced photometric stereo technique (PST) was integrated into the scDCT system to obtain the surface geometry in real time for image reconstruction. Computer simulations demonstrated that a priori knowledge of tissue surface geometry is crucial for precisely reconstructing the anomaly with blood flow contrast. Importantly, the innovative integration design with one single- EMCCD camera for both PST and scDCT data collection obviates the need for offline alignment of sources and detectors on the tissue boundary. The in vivo imaging capability of the updated scDCT is demonstrated by imaging dynamic changes in forearm blood flow distribution during a cuff-occlusion procedure. The feasibility and safety in clinical use are evidenced by intraoperative imaging of mastectomy skin flaps and comparison with fluorescence angiography. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Diffuse optical measurements of head and neck tumor hemodynamics for early prediction of chemoradiation therapy outcomes
- Author
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E Johnson, Chong Huang, Li Chen, Mahesh Kudrimoti, Sameera S. Kumar, Brent J. Shelton, Guoqiang Yu, Lixin Dong, Daniel Irwin, Scott D. Stevens, and Yu Shang
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Biomedical Engineering ,Urology ,Hemodynamics ,01 natural sciences ,010309 optics ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,Research Papers: General ,0103 physical sciences ,medicine ,Humans ,Oxygen saturation (medicine) ,Receiver operating characteristic ,business.industry ,Head and neck cancer ,Chemoradiotherapy ,Blood flow ,medicine.disease ,Primary tumor ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Surgery ,Radiation therapy ,Treatment Outcome ,medicine.anatomical_structure ,Head and Neck Neoplasms ,Cervical lymph nodes ,Oxyhemoglobins ,030220 oncology & carcinogenesis ,business - Abstract
This study used a hybrid near-infrared diffuse optical instrument to monitor tumor hemodynamic responses to chemoradiation therapy for early prediction of treatment outcomes in patients with head and neck cancer. Forty-seven patients were measured once per week to evaluate the hemodynamic status of clinically involved cervical lymph nodes as surrogates for the primary tumor response. Patients were classified into two groups: complete response (CR) (n=29) and incomplete response (IR) (n=18). Tumor hemodynamic responses were found to be associated with clinical outcomes (CR/IR), wherein the associations differed depending on human papillomavirus (HPV-16) status. In HPV-16 positive patients, significantly lower levels in tumor oxygenated hemoglobin concentration ([HbO2]) at weeks 1 to 3, total hemoglobin concentration at week 3, and blood oxygen saturation (StO2) at week 3 were found in the IR group. In HPV-16 negative patients, significantly higher levels in tumor blood flow index and reduced scattering coefficient (μs′) at week 3 were observed in the IR group. These hemodynamic parameters exhibited significantly high accuracy for early prediction of clinical outcomes, within the first three weeks of therapy, with the areas under the receiver operating characteristic curves (AUCs) ranging from 0.83 to 0.96.
- Published
- 2016
8. Low-cost compact diffuse speckle contrast flowmeter using small laser diode and bare charge-coupled-device
- Author
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Joshua Paul Morgan, Jeffrey Todd Hastings, Jae Gwan Kim, Siavash Mazdeyasna, Chong Huang, Guoqiang Yu, and Myeongsu Seong
- Subjects
Materials science ,Biomedical Engineering ,02 engineering and technology ,01 natural sciences ,Imaging phantom ,Flow measurement ,law.invention ,Semiconductor laser theory ,010309 optics ,Biomaterials ,Speckle pattern ,Optics ,law ,0103 physical sciences ,Laser-Doppler Flowmetry ,Humans ,Spectroscopy ,Laser diode ,Phantoms, Imaging ,business.industry ,Spectrum Analysis ,Hemodynamics ,Blood flow ,JBO Letters ,021001 nanoscience & nanotechnology ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Forearm ,Regional Blood Flow ,0210 nano-technology ,business - Abstract
We report a low-cost compact diffuse speckle contrast flowmeter (DSCF) consisting of a small laser diode and a bare charge-coupled-device (CCD) chip, which can be used for contact measurements of blood flow variations in relatively deep tissues (up to ∼ 8 mm). Measurements of large flow variations by the contact DSCF probe are compared to a noncontact CCD-based diffuse speckle contrast spectroscopy and a standard contact diffuse correlation spectroscopy in tissue phantoms and a human forearm. Bland–Altman analysis shows no significant bias with good limits of agreement among these measurements: 96.5%±2.2% (94.4% to 100.0%) in phantom experiments and 92.8% in the forearm test. The relatively lower limit of agreement observed in the in vivo measurements (92.8%) is likely due to heterogeneous reactive responses of blood flow in different regions/volumes of the forearm tissues measured by different probes. The low-cost compact DSCF device holds great potential to be broadly used for continuous and longitudinal monitoring of blood flow alterations in ischemic/hypoxic tissues, which are usually associated with various vascular diseases.
- Published
- 2016
9. Optical measurement of cerebral hemodynamics and oxygen metabolism in neonates with congenital heart defects
- Author
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Stefanie E. Mason, Chao Zhou, Guoqiang Yu, Joel H. Greenberg, Erin M. Buckley, Turgut Durduran, John A. Detre, Arjun G. Yodh, Daniel J. Licht, Regine Choe, Suzanne Durning, Jiongjiong Wang, Susan C. Nicolson, J. William Gaynor, Meeri N. Kim, Robert A. Zimmerman, Thomas L. Spray, Lisa M. Montenegro, and Mary E. Putt
- Subjects
Heart Defects, Congenital ,medicine.medical_specialty ,Optics and Photonics ,Heart disease ,Population ,Biomedical Engineering ,Hemodynamics ,chemistry.chemical_element ,Oxygen ,Biomaterials ,Hypercapnia ,Hemoglobins ,Internal medicine ,Medicine ,Humans ,education ,Cerebral Cortex ,education.field_of_study ,Spectroscopy, Near-Infrared ,medicine.diagnostic_test ,business.industry ,Oxygen metabolism ,Spectrum Analysis ,Infant, Newborn ,Magnetic resonance imaging ,Carbon Dioxide ,medicine.disease ,Magnetic Resonance Imaging ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Cerebral blood flow ,chemistry ,Regional Blood Flow ,Anesthesia ,Oxyhemoglobins ,Cardiology ,medicine.symptom ,business ,Research Papers: Sensing - Abstract
We employ a hybrid diffuse correlation spec- troscopy DCS and near-infrared spectroscopy NIRS monitor for neonates with congenital heart disease n=33. The NIRS-DCS device measured changes during hypercapnia of oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations; cerebral blood flow rCBFDCS; and oxygen metabolism rCMRO2. Concur- rent measurements with arterial spin-labeled magnetic resonance imaging rCBFASL-MRI, n=12 cross-validate rCBFDCS against rCBFASL-MRI, showing good agreement R=0.7, p=0.01. The study demonstrates use of NIRS- DCS on a critically ill neonatal population, and the results indicate that the optical technology is a promising clinical method for monitoring this population. © 2010 Society of Photo
- Published
- 2010
10. Diffuse optical monitoring of blood flow and oxygenation in human breast cancer during early stages of neoadjuvant chemotherapy
- Author
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Albert E. Cerussi, Bruce J. Tromberg, Turgut Durduran, Guoqiang Yu, Natasha Shah, Chao Zhou, Rita S. Mehta, Regine Choe, Arjun G. Yodh, Amanda Durkin, David Hsiang, and John Butler
- Subjects
Pathology ,medicine.medical_specialty ,Spectrophotometry, Infrared ,Haemodynamic response ,medicine.medical_treatment ,Biomedical Engineering ,Urology ,Hemodynamics ,Breast Neoplasms ,Biomaterials ,Hemoglobins ,Breast cancer ,medicine ,Humans ,Tomography, Optical ,Neoadjuvant therapy ,Chemotherapy ,business.industry ,Cancer ,Oxygenation ,Blood flow ,Middle Aged ,medicine.disease ,Atomic and Molecular Physics, and Optics ,Neoadjuvant Therapy ,Electronic, Optical and Magnetic Materials ,Oxygen ,Chemotherapy, Adjuvant ,Female ,business ,Biomarkers ,Blood Flow Velocity - Abstract
We combine diffuse optical spectroscopy DOS and dif- fuse correlation spectroscopy DCS to noninvasively monitor early hemodynamic response to neoadjuvant chemotherapy in a breast cancer patient. The potential for early treatment monitoring is dem- onstrated. Within the first week of treatment day 7 DOS revealed significant changes in tumor/normal contrast compared to pretreat- ment day 0 tissue concentrations of deoxyhemoglobin rctHHbT/N =69±21%, oxyhemoglobin rctO2HbT/N=73±25%, total hemo- globin rctTHbT/N=72±17%, and lipid concentration rctLipidT/N =116±13%. Similarly, DCS found significant changes in tumor/ normal blood flow contrast rBFT/N=75±7%on day 7 with respect to day 0. Our observations suggest the combination of DCS and DOS enhances treatment monitoring compared to either technique alone. The hybrid approach also enables construction of indices reflecting tissue metabolic rate of oxygen, which may provide new insights about therapy mechanisms. © 2007 Society of Photo-Optical Instrumentation Engi
- Published
- 2007
11. Time-dependent blood flow and oxygenation in human skeletal muscles measured with noninvasive near-infrared diffuse optical spectroscopies
- Author
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Arjun G. Yodh, Guoqiang Yu, Emile R. Mohler, Britton Chance, Gwen Lech, Turgut Durduran, and Chao Zhou
- Subjects
Adult ,Male ,Pathology ,medicine.medical_specialty ,Time Factors ,Biomedical Engineering ,Hemodynamics ,Microcirculation ,Biomaterials ,Hemoglobins ,Oxygen Consumption ,Occlusion ,Medicine ,Humans ,Muscle, Skeletal ,Exercise ,Peripheral Vascular Diseases ,Spectroscopy, Near-Infrared ,business.industry ,Foot ,Near-infrared spectroscopy ,Oxygenation ,Blood flow ,Arteries ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Peripheral ,Oxygen ,Regional Blood Flow ,Case-Control Studies ,Cuff ,Female ,business ,Biomedical engineering - Abstract
We have employed near-infrared optical methods to mea- sure noninvasively the dynamics of muscle blood flow and oxygen saturation (StO2) during cuff occlusion and plantar flexion exercise. Relative muscle oxygen consumption (rVO2) was also computed from these data. Diffuse correlation spectroscopy provides information about blood flow, and diffuse reflectance spectroscopy provides infor- mation about blood oxygenation. Ten healthy subjects and one pa- tient with peripheral arterial disease (PAD) were studied during 3-min arterial cuff occlusion of arm and leg, and during 1-min plantar flex- ion exercise. Signals from different layers (cutaneous tissues and muscles) during cuff occlusion were differentiated, revealing strong hemodynamic responses from muscle layers. During exercise in healthy legs, the observed ;4.7 fold increase in relative blood flow (rBF) was significantly lower than the corresponding increase in rVO2 (;7 fold). The magnitudes of rBF and rVO2 during exercise in the PAD patient were ;1/2 of the healthy controls, and the StO2 recovery time was twice that of the controls. The hybrid instrument improves upon current technologies for measuring muscle responses by simul- taneously measuring rBF and StO2 . The instrument thus provides a method for evaluation of microcirculation and muscle metabolism in patients with vascular diseases. © 2005 Society of Photo-Optical Instrumentation
- Published
- 2005
12. Diffuse optical measurements of head and neck tumor hemodynamics for early prediction of chemoradiation therapy outcomes.
- Author
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Lixin Dong, Kudrimoti, Mahesh, Irwin, Daniel, Li Chen, Kumar, Sameera, Yu Shang, Chong Huang, Johnson, Ellis L., Stevens, Scott D., Shelton, Brent J., and Guoqiang Yu
- Subjects
INFRARED imaging ,HEAD & neck cancer diagnosis ,HEAD & neck cancer treatment ,NECK injuries ,SHRUNKEN heads ,TREATMENT effectiveness - Abstract
This study used a hybrid near-infrared diffuse optical instrument to monitor tumor hemodynamic responses to chemoradiation therapy for early prediction of treatment outcomes in patients with head and neck cancer. Forty-seven patients were measured once per week to evaluate the hemodynamic status of clinically involved cervical lymph nodes as surrogates for the primary tumor response. Patients were classified into two groups: complete response (CR) (n = 29) and incomplete response (IR) (n = 18). Tumor hemodynamic responses were found to be associated with clinical outcomes (CR/IR), wherein the associations differed depending on human papillomavirus (HPV-16) status. In HPV-16 positive patients, significantly lower levels in tumor oxygenated hemoglobin concentration ([HbO
2 ]) at weeks 1 to 3, total hemoglobin concentration at week 3, and blood oxygen saturation (StO2 ) at week 3 were found in the IR group. In HPV-16 negative patients, significantly higher levels in tumor blood flow index and reduced scattering coefficient (μ's ) at week 3 were observed in the IR group. These hemodynamic parameters exhibited significantly high accuracy for early prediction of clinical outcomes, within the first three weeks of therapy, with the areas under the receiver operating characteristic curves (AUCs) ranging from 0.83 to 0.96. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
13. Low-cost compact diffuse speckle contrast flowmeter using small laser diode and bare charge-coupled-device.
- Author
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Chong Huang, Myeongsu Seong, Morgan, Joshua Paul, Mazdeyasna, Siavash, Jae Gwan Kim, Hastings, Jeffrey Todd, and Guoqiang Yu
- Subjects
FLOW meters ,DIAGNOSTIC imaging ,BLOOD flow measurement ,BLOOD circulation measurement ,FLOW measurement - Abstract
We report a low-cost compact diffuse speckle contrast flowmeter (DSCF) consisting of a small laser diode and a bare charge-coupled-device (CCD) chip, which can be used for contact measurements of blood flow variations in relatively deep tissues (up to ∼8 mm). Measurements of large flow variations by the contact DSCF probe are compared to a noncontact CCD-based diffuse speckle contrast spectroscopy and a standard contact diffuse correlation spectroscopy in tissue phantoms and a human forearm. Bland-Altman analysis shows no significant bias with good limits of agreement among these measurements: 96.5% ± 2.2% (94.4% to 100.0%) in phantom experiments and 92.8% in the forearm test. The relatively lower limit of agreement observed in the in vivo measurements (92.8%) is likely due to heterogeneous reactive responses of blood flow in different regions/volumes of the forearm tissues measured by different probes. The low-cost compact DSCF device holds great potential to be broadly used for continuous and longitudinal monitoring of blood flow alterations in ischemic/hypoxic tissues, which are usually associated with various vascular diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
14. Hybrid diffuse optical techniques for continuous hemodynamic measurement in gastrocnemius during plantar flexion exercise.
- Author
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Henry, Brad, Mingjun Zhao, Yu Shang, Uhl, Timothy, Thomas, D. Travis, Xenos, Eleftherios S., Saha, Sibu P., and Guoqiang Yu
- Subjects
HEMODYNAMICS ,BLOOD circulation ,OXYGENATORS ,BLOOD flow ,BODY fluid flow - Abstract
Occlusion calibrations and gating techniques have been recently applied by our laboratory for continuous and absolute diffuse optical measurements of forearm muscle hemodynamics during handgrip exercises. The translation of these techniques from the forearm to the lower limb is the goal of this study as various diseases preferentially affect muscles in the lower extremity. This study adapted a hybrid near-infrared spectroscopy and diffuse correlation spectroscopy system with a gating algorithm to continuously quantify hemodynamic responses of medial gastrocnemius during plantar flexion exercises in 10 healthy subjects. The outcomes from optical measurement include oxy-, deoxy-, and total hemoglobin concentrations, blood oxygen saturation, and relative changes in blood flow (rBF) and oxygen consumption rate (r...O
2 ). We calibrated rBF and r...O2 profiles with absolute baseline values of BF and ...O2 obtained by venous and arterial occlusions, respectively. Results from this investigation were comparable to values from similar studies. Additionally, significant correlation was observed between resting local muscle BF measured by the optical technique and whole limb BF measured concurrently by a strain gauge venous plethysmography. The extensive hemodynamic and metabolic profiles during exercise will allow for future comparison studies to investigate the diagnostic value of hybrid technologies in muscles affected by disease. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
15. Noncontact diffuse correlation tomography of human breast tumor.
- Author
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Lian He, Yu Lin, Chong Huang, Irwin, Daniel, Szabunio, Margaret M., and Guoqiang Yu
- Subjects
BREAST tumor diagnosis ,TOMOGRAPHY ,BLOOD flow ,IMAGE reconstruction ,HEMODYNAMICS ,SURFACE geometry - Abstract
Our first step to adapt our recently developed noncontact diffuse correlation tomography (ncDCT) system for three-dimensional (3-D) imaging of blood flow distribution in human breast tumors is reported. A commercial 3-D camera was used to obtain breast surface geometry, which was then converted to a solid volume mesh. An ncDCT probe scanned over a region of interest on the mesh surface and the measured boundary data were combined with a finite element framework for 3-D image reconstruction of blood flow distribution. This technique was tested in computer simulations and in vivo human breasts with low-grade carcinoma. Results from computer simulations suggest that relatively high accuracy can be achieved when the entire tumor is within the sensitive region of diffuse light. Image reconstruction with a priori knowledge of the tumor volume and location can significantly improve the accuracy in recovery of tumor blood flow contrasts. In vivo imaging results from two breast carcinomas show higher average blood flow contrasts (5.9- and 10.9-fold) in the tumor regions compared to the surrounding tissues, which are comparable with previous findings using diffuse correlation spectroscopy. The ncDCT system has the potential to image blood flow distributions in soft and vulnerable tissues without distorting tissue hemodynamics. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
16. Diffuse optical characterization of an exercising patient group with peripheral artery disease
- Author
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Turgut Durduran, Sung Wan Han, Arjun G. Yodh, Yu Shang, Malavika Chandra, Xiaoman Xing, Emile R. Mohler, Gwen Lech, Rickson C. Mesquita, Guoqiang Yu, Mary E. Putt, and Chao Zhou
- Subjects
Male ,medicine.medical_specialty ,Haemodynamic response ,Biomedical Engineering ,Hemodynamics ,Statistics, Nonparametric ,Biomaterials ,Internal medicine ,medicine ,Humans ,Ankle Brachial Index ,Treadmill ,Exercise ,Depression (differential diagnoses) ,Aged ,Peripheral Vascular Diseases ,Leg ,Spectroscopy, Near-Infrared ,business.industry ,Spectrum Analysis ,Case-control study ,Oxygenation ,Blood flow ,Middle Aged ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Surgery ,Oxygen ,medicine.anatomical_structure ,Regional Blood Flow ,Case-Control Studies ,Cardiology ,Female ,Ankle ,business ,Research Papers: Sensing - Abstract
Peripheral artery disease (PAD) is a common condition with high morbidity. While measurement of tissue oxygen saturation (S(t)O(2)) has been demonstrated, this is the first study to assess both S(t)O(2) and relative blood flow (rBF) in the extremities of PAD patients. Diffuse optics is employed to measure hemodynamic response to treadmill and pedal exercises in 31 healthy controls and 26 patients. For S(t)O(2), mild and moderate/severe PAD groups show pronounced differences compared with controls. Pre-exercise mean S(t)O(2) is lower in PAD groups by 9.3% to 10.6% compared with means of 63.5% to 66.2% in controls. For pedal, relative rate of return of S(t)O(2) to baseline is more rapid in controls (p0.05). Patterns of rBF also differ among groups. After both exercises, rBF tend to occur at depressed levels among severe PAD patients compared with healthy (p0.05); post-treadmill, rBF tend to occur at elevated levels among healthy compared with severe PAD patients (p0.05). Additionally, relative rate of return to baseline S(t)O(2) is more rapid among subjects with reduced levels of depression in rBF (p = 0.041), even after adjustment for ankle brachial index. This suggests a physiologic connection between rBF and oxygenation that can be measured using diffuse optics, and potentially employed as an evaluative tool in further studies.
- Published
- 2013
17. Near-infrared diffuse correlation spectroscopy in cancer diagnosis and therapy monitoring
- Author
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Guoqiang Yu
- Subjects
medicine.medical_specialty ,Pathology ,medicine.medical_treatment ,Biomedical Engineering ,Cancer therapy ,Biomaterials ,Mice ,Neoplasms ,Animals ,Humans ,Medicine ,Review Papers ,Monitoring, Physiologic ,Spectroscopy, Near-Infrared ,business.industry ,Near-infrared spectroscopy ,Cancer ,Diffuse correlation spectroscopy ,Blood flow ,medicine.disease ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Radiation therapy ,High temporal resolution ,Therapy monitoring ,Radiology ,business - Abstract
A novel near-infrared (NIR) diffuse correlation spectroscopy (DCS) for tumor blood flow measurement is introduced in this review paper. DCS measures speckle fluctuations of NIR diffuse light in tissue, which are sensitive to the motions of red blood cells. DCS offers several attractive new features for tumor blood flow measurement such as noninvasiveness, portability, high temporal resolution, and relatively large penetration depth. DCS technology has been utilized for continuous measurement of tumor blood flow before, during, and after cancer therapies. In those pilot investigations, DCS hemodynamic measurements add important new variables into the mix for differentiation of benign from malignant tumors and for prediction of treatment outcomes. It is envisaged that with more clinical applications in large patient populations, DCS might emerge as an important method of choice for bedside management of cancer therapy, and it will certainly provide important new information about cancer physiology that may be of use in diagnosis.
- Published
- 2012
18. Noncontact diffuse correlation spectroscopy for noninvasive deep tissue blood flow measurement
- Author
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Lian He, Guoqiang Yu, Yu Shang, and Yu Lin
- Subjects
Materials science ,Biomedical Engineering ,Hemodynamics ,Imaging phantom ,Diffusion ,Biomaterials ,Optics ,Human muscle ,Deep tissue ,Humans ,Spectroscopy ,Spectroscopy, Near-Infrared ,Phantoms, Imaging ,business.industry ,Detector ,Diffuse correlation spectroscopy ,Blood flow ,JBO Letters ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Forearm ,sense organs ,business ,Blood Flow Velocity ,Biomedical engineering - Abstract
A noncontact diffuse correlation spectroscopy (DCS) probe has been developed using two separated optical paths for the source and detector. This unique design avoids the interference between the source and detector and allows large source-detector separations for deep tissue blood flow measurements. The noncontact probe has been calibrated against a contact probe in a tissue-like phantom solution and human muscle tissues; flow changes concurrently measured by the two probes are highly correlated in both phantom (R(2)=0.89, p10(-5)) and real-tissue (R(2)=0.77, p10(-5), n=9) tests. The noncontact DCS holds promise for measuring blood flow in vulnerable (e.g., pressure ulcer) and soft (e.g., breast) tissues without distorting tissue hemodynamic properties.
- Published
- 2012
19. Intraoperative evaluation of revascularization effect on ischemic muscle hemodynamics using near-infrared diffuse optical spectroscopies
- Author
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Sibu P. Saha, Lixin Dong, Youquan Zhao, Guoqiang Yu, Yu Shang, and Ran Cheng
- Subjects
medicine.medical_specialty ,Arterial blood supply ,Percutaneous ,medicine.medical_treatment ,Biomedical Engineering ,Ischemia ,Hemodynamics ,Revascularization ,Diffusion ,Biomaterials ,Internal medicine ,Humans ,Medicine ,Oximetry ,Intraoperative Care ,Spectroscopy, Near-Infrared ,business.industry ,Muscles ,Oxygenation ,Blood flow ,medicine.disease ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Peripheral ,Surgery ,Oxygen ,Treatment Outcome ,Cardiology ,Vascular Grafting ,business ,Research Papers: Sensing - Abstract
Arterial revascularization in patients with peripheral arterial disease (PAD) reestablishes large arterial blood supply to the ischemic muscles in lower extremities via bypass grafts or percutaneous transluminal angioplasty (PTA). Currently no gold standard is available for assessment of revascularization effects in lower extremity muscles. This study tests a novel near-infrared diffuse correlation spectroscopy flow-oximeter for monitoring of blood flow and oxygenation changes in medial gastrocnemius (calf) muscles during arterial revascularization. Twelve limbs with PAD undergoing revascularization were measured using a sterilized fiber-optic probe taped on top of the calf muscle. The optical measurement demonstrated sensitivity to dynamic physiological events, such as arterial clamping/releasing during bypass graft and balloon inflation/deflation during PTA. Significant elevations in calf muscle blood flow were observed after revascularization in patients with bypass graft (+48.1 ± 17.5%) and patients with PTA (+43.2 ± 11.0%), whereas acute post-revascularization effects in muscle oxygenation were not evident. The decoupling of flow and oxygenation after revascularization emphasizes the need for simultaneous measurement of both parameters. The acute elevations/improvements in calf muscle blood flow were associated with significant improvements in symptoms and functions. In total, the investigation corroborates potential of the optical methods for objectively assessing the success of arterial revascularization.
- Published
- 2011
20. Diffuse optical monitoring of hemodynamic changes in piglet brain with closed head injury
- Author
-
Chao Zhou, Arjun G. Yodh, Turgut Durduran, Rebecca Ichord, Stephanie A. Eucker, Guoqiang Yu, Susan S. Margulies, Stuart H. Friess, and Jill Ralston
- Subjects
Optics and Photonics ,Apnea ,Swine ,Traumatic brain injury ,Biomedical Engineering ,Hemodynamics ,Article ,Fluorescence ,Biomaterials ,Hemoglobins ,Head Injuries, Closed ,medicine ,Animals ,Oximetry ,Analysis of Variance ,Spectroscopy, Near-Infrared ,business.industry ,Spectrum Analysis ,Brain ,Reproducibility of Results ,Blood flow ,medicine.disease ,Atomic and Molecular Physics, and Optics ,Heart Arrest ,Electronic, Optical and Magnetic Materials ,Hypertonic saline ,Oxygen ,Disease Models, Animal ,Blood pressure ,Animals, Newborn ,Cerebral blood flow ,Brain Injuries ,Oxyhemoglobins ,Anesthesia ,Closed head injury ,Linear Models ,Female ,medicine.symptom ,business - Abstract
We used a nonimpact inertial rotational model of a closed head injury in neonatal piglets to simulate the conditions following traumatic brain injury in infants. Diffuse optical techniques, including diffuse reflectance spectroscopy and diffuse correlation spectroscopy (DCS), were used to measure cerebral blood oxygenation and blood flow continuously and noninvasively before injury and up to 6 h after the injury. The DCS measurements of relative cerebral blood flow were validated against the fluorescent microsphere method. A strong linear correlation was observed between the two techniques (R = 0.89, p < 0.00001). Injury-induced cerebral hemodynamic changes were quantified, and significant changes were found in oxy- and deoxy-hemoglobin concentrations, total hemoglobin concentration, blood oxygen saturation, and cerebral blood flow after the injury. The diffuse optical measurements were robust and also correlated well with recordings of vital physiological parameters over the 6-h monitoring period, such as mean arterial blood pressure, arterial oxygen saturation, and heart rate. Finally, the diffuse optical techniques demonstrated sensitivity to dynamic physiological events, such as apnea, cardiac arrest, and hypertonic saline infusion. In total, the investigation corraborates potential of the optical methods for bedside monitoring of pediatric and adult human patients in the neurointensive care unit.
- Published
- 2009
21. Noncontact diffuse optical assessment of blood flow changes in head and neck free tissue transfer flaps.
- Author
-
Chong Huang, Radabaugh, Jeffrey P., Aouad, Rony K., Yu Lin, Gal, Thomas J., Patel, Amit B., Valentino, Joseph, Yu Shang, and Guoqiang Yu
- Subjects
SURGICAL flaps ,BLOOD flow ,SPECTROMETRY ,HEAD & neck cancer ,SURGICAL anastomosis - Abstract
Knowledge of tissue blood flow (BF) changes after free tissue transfer may enable surgeons to predict the failure of flap thrombosis at an early stage. This study used our recently developed noncontact diffuse correlation spectroscopy to monitor dynamic BF changes in free flaps without getting in contact with the targeted tissue. Eight free flaps were elevated in patients with head and neck cancer; one of the flaps failed. Multiple BF measurements probing the transferred tissue were performed during and post the surgical operation. Postoperative BF values were normalized to the intraoperative baselines (assigning "1") for the calculation of relative BF change (rBF). The rBF changes over the seven successful flaps were 1.89 ± 0.15, 2.26 ± 0.13, and 2.43 ± 0.13 (mean ± standard error), respectively, on postoperative days 2, 4, and 7. These postoperative values were significantly higher than the intraoperative baseline values (p < 0.001), indicating a gradual recovery of flap vascularity after the tissue transfer. By contrast, rBF changes observed from the unsuccessful flaps were 1.14 and 1.34, respectively, on postoperative days 2 and 4, indicating less flow recovery. Measurement of BF recovery after flap anastomosis holds the potential to act early to salvage ischemic flaps. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. Noninvasive diffuse optical measurement of blood flow and blood oxygenation for monitoring radiation therapy in patients with head and neck tumors: a pilot study
- Author
-
Jun Zhang, Turgut Durduran, Juan Du, Robert A. Lustig, Harry Quon, A. Kilger, Regine Choe, Ulas Sunar, Britton Chance, Laurie A. Loevner, Arjun G. Yodh, Shoko Nioka, Chao Zhou, and Guoqiang Yu
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Biomedical Engineering ,Pilot Projects ,Sensitivity and Specificity ,Biomaterials ,Hemoglobins ,Biomarkers, Tumor ,Humans ,Tissue oxygen ,Medicine ,In patient ,Aged ,business.industry ,Spectrum Analysis ,Head and neck tumors ,Reproducibility of Results ,Diffuse correlation spectroscopy ,Blood flow ,Middle Aged ,Prognosis ,Radiotherapy, Computer-Assisted ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Surgery ,Oxygen ,Radiation therapy ,Treatment Outcome ,Head and Neck Neoplasms ,Blood oxygenation ,Feasibility Studies ,Female ,Therapy monitoring ,Nuclear medicine ,business ,Blood Flow Velocity - Abstract
This pilot study explores the potential of noninvasive diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS) for monitoring early relative blood flow (rBF), tissue oxygen saturation (StO(2)), and total hemoglobin concentration (THC) responses to chemo-radiation therapy in patients with head and neck tumors. rBF, StO(2), and THC in superficial neck tumor nodes of eight patients are measured before and during the chemo-radiation therapy period. The weekly rBF, StO(2), and THC kinetics exhibit different patterns for different individuals, including significant early blood flow changes during the first two weeks. Averaged blood flow increases (52.7+/-9.7)% in the first week and decreases (42.4+/-7.0)% in the second week. Averaged StO(2) increases from (62.9+/-3.4)% baseline value to (70.4+/-3.2)% at the end of the second week, and averaged THC exhibits a continuous decrease from pretreatment value of (80.7+/-7.0) [microM] to (73.3+/-8.3) [microM] at the end of the second week and to (63.0+/-8.1) [microM] at the end of the fourth week of therapy. These preliminary results suggest daily diffuse-optics-based therapy monitoring is feasible during the first two weeks and may have clinical promise.
- Published
- 2006
23. Near-infrared diffuse optical monitoring of cerebral blood flow and oxygenation for the prediction of vasovagal syncope.
- Author
-
Ran Cheng, Yu Shang, Siqi Wang, Evans, Joyce M., Rayapati, Abner, Randall, David C., and Guoqiang Yu
- Subjects
BLOOD pressure ,HEMODYNAMICS ,SYNCOPE ,CEREBRAL circulation ,PLETHYSMOGRAPHY - Abstract
Significant drops in arterial blood pressure and cerebral hemodynamics have been previously observed during vasovagal syncope (VVS). Continuous and simultaneous monitoring of these physiological variables during VVS is rare, but critical for determining which variable is the most sensitive parameter to predict VVS. The present study used a novel custom-designed diffuse correlation spectroscopy flow-oximeter and a finger plethysmograph to simultaneously monitor relative changes of cerebral blood flow (rCBF), cerebral oxygenation (i.e., oxygenated/deoxygenated/total hemoglobin concentration: r[HbO
2 ]/r[Hb]/rTHC), and mean arterial pressure (rMAP) during 70 deg head-up tilt (HUT) in 14 healthy adults. Six subjects developed presyncope during HUT. Two-stage physiological responses during HUT were observed in the presyncopal group: slow and small changes in measured variables (i.e., Stage I), followed by rapid and dramatic decreases in rMAP, rCBF, r[HbO2 , and rTHC (i.e., Stage II). Compared to other physiological variables, rCBF reached its breakpoint between the two stages earliest and had the largest decrease (76 ± 8%) during presyncope. Our results suggest that rCBF has the best sensitivity for the assessment of VVS. Most importantly, a threshold of ~50% rCBF decline completely separated the subjects from those without presyncope, suggesting its potential for predicting VVS. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
24. Noninvasive evaluation of electrical stimulation impacts on muscle hemodynamics via integrating diffuse optical spectroscopies with muscle stimulator.
- Author
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Yu Shang, Yu Lin, Henry, Brad A., Ran Cheng, Chong Huang, Li Chen, Shelton, Brent J., Swartz, Karin R., Salles, Sara S., and Guoqiang Yu
- Subjects
ELECTRIC stimulation research ,MUSCLES ,HEMODYNAMICS ,DIAGNOSTIC imaging research ,BLOOD circulation ,OXYGENATION (Chemistry) - Abstract
Technologies currently available for the monitoring of electrical stimulation (ES) in promoting blood circulation and tissue oxygenation are limited. This study integrated a muscle stimulator with a diffuse correlation spectroscopy (DCS) flow-oximeter to noninvasively quantify muscle blood flow and oxygenation responses during ES. Ten healthy subjects were tested using the integrated system. Themuscle stimulator delivered biphasic electrical current to right leg quadriceps muscle, and a custom-made DCS flow-oximeter was used for simultaneous measurements of muscle blood flow and oxygenation in both legs. To minimize motion artifact of muscle fibers during ES, a novel gating algorithm was developed for data acquisition at the time when the muscle was relaxed. ES at 2, 10, and 50 Hz were applied for 20 min on each subject in three days sequentially. Results demonstrate that the 20-min ES at all frequencies promoted muscle blood flow significantly. However, only the ES at 10 Hz resulted in significant and persistent increases in oxy-hemoglobin concentration during and post ES. This pilot study supports the application of the integrated system to quantify tissue hemodynamic improvements for the optimization of ES treatment in patients suffering from diseases caused by poor blood circulation and low tissue oxygenation (e.g., pressure ulcer). [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
25. Diffuse optical characterization of an exercising patient group with peripheral artery disease.
- Author
-
Mesquita, Rickson C., Putt, Mary, Chandra, Malavika, Guoqiang Yu, Xiaoman Xing, Sung Wan Han, Lech, Gwen, Yu Shang, Durduran, Turgut, Chao Zhou, Yodh, Arjun G., and Mohler III, Emile R.
- Subjects
ARTERIAL diseases ,NEAR infrared spectroscopy ,MUSCLE blood-vessels ,BLOOD flow ,CARDIOVASCULAR diseases ,HEMODYNAMICS - Abstract
Peripheral artery disease (PAD) is a common condition with high morbidity. While measurement of tissue oxygen saturation (S
t O2 ) has been demonstrated, this is the first study to assess both St O2 and relative blood flow (rBF) in the extremities of PAD patients. Diffuse optics is employed to measure hemodynamic response to treadmill and pedal exercises in 31 healthy controls and 26 patients. For St O2 , mild and moderate/severe PAD groups show pronounced differences compared with controls. Pre-exercise mean St O2 is lower in PAD groups by 9.3%to 10.6% compared with means of 63.5% to 66.2% in controls. For pedal, relative rate of return of St O2 to baseline is more rapid in controls (p < 0.05). Patterns of rBF also differ among groups. After both exercises, rBF tend to occur at depressed levels among severe PAD patients compared with healthy (p < 0.05); post-treadmill, rBF tend to occur at elevated levels among healthy compared with severe PAD patients (p < 0.05). Additionally, relative rate of return to baseline St O2 is more rapid among subjects with reduced levels of depression in rBF (p = 0.041), even after adjustment for ankle brachial index. This suggests a physiologic connection between rBF and oxygenation that can be measured using diffuse optics, and potentially employed as an evaluative tool in further studies. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
26. Time-dependent blood flow and oxygenation in human skeletal muscles measured with noninvasive near-infrared diffuse optical spectroscopies.
- Author
-
Guoqiang Yu, Durduran, Turgut, Lech, Gwen, Chao Zhou, Chance, Britton, Mohler III, Emile R., and Yodh, Arjun G.
- Published
- 2005
- Full Text
- View/download PDF
27. Intraoperative evaluation of revascularization effect on ischemic muscle hemodynamics using near-infrared diffuse optical spectroscopies.
- Author
-
Guoqiang Yu, Yu Shang, Youquan Zhao, Ran Cheng, Lixin Dong, and Sibu P. Saha
- Subjects
- *
PERIPHERAL vascular diseases , *SURGERY , *REVASCULARIZATION (Surgery) , *INTRAOPERATIVE monitoring , *ISCHEMIA , *HEMODYNAMICS , *OPTICAL spectroscopy , *OXIMETRY , *TRANSLUMINAL angioplasty - Abstract
Arterial revascularization in patients with peripheral arterial disease (PAD) reestablishes large arterial blood supply to the ischemic muscles in lower extremities via bypass grafts or percutaneous transluminal angioplasty (PTA). Currently no gold standard is available for assessment of revascularization effects in lower extremity muscles. This study tests a novel near-infrared diffuse correlation spectroscopy flow-oximeter for monitoring of blood flow and oxygenation changes in medial gastrocnemius (calf) muscles during arterial revascularization. Twelve limbs with PAD undergoing revascularization were measured using a sterilized fiber-optic probe taped on top of the calf muscle. The optical measurement demonstrated sensitivity to dynamic physiological events, such as arterial clampingreleasing during bypass graft and balloon inflationdeflation during PTA. Significant elevations in calf muscle blood flow were observed after revascularization in patients with bypass graft (48.1 ± 17.5) and patients with PTA (43.2 ± 11.0), whereas acute post-revascularization effects in muscle oxygenation were not evident. The decoupling of flow and oxygenation after revascularization emphasizes the need for simultaneous measurement of both parameters. The acute elevationsimprovements in calf muscle blood flow were associated with significant improvements in symptoms and functions. In total, the investigation corroborates potential of the optical methods for objectively assessing the success of arterial revascularization. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
28. Optical measurement of cerebral hemodynamics and oxygen metabolism in neonates with congenital heart defects.
- Author
-
Turgut Durduran, Chao Zhou, Erin M. Buckley, Meeri N. Kim, Guoqiang Yu, Regine Choe, J. William Gaynor, Thomas L. Spray, Suzanne M. Durning, Stefanie E. Mason, Lisa M. Montenegro, Susan C. Nicolson, Robert A. Zimmerman, Mary E. Putt, Jiongjiong Wang, Joel H. Greenberg, John A. Detre, Arjun G. Yodh, and Daniel J. Licht
- Subjects
OPTICAL measurements ,CONGENITAL heart disease ,NEAR infrared spectroscopy ,HEMODYNAMIC monitoring ,METABOLISM ,PHYSIOLOGICAL effects of oxygen ,CEREBRAL circulation ,MEDICAL imaging systems - Abstract
We employ a hybrid diffuse correlation spectroscopy (DCS) and near-infrared spectroscopy (NIRS) monitor for neonates with congenital heart disease (n=33). The NIRS-DCS device measured changes during hypercapnia of oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations; cerebral blood flow (rCBFDCS); and oxygen metabolism (rCMRO2). Concurrent measurements with arterial spin-labeled magnetic resonance imaging (rCBFASL-MRI, n=12) cross-validate rCBFDCSagainst rCBFASL-MRI, showing good agreement (R=0.7, p=0.01). The study demonstrates use of NIRS-DCS on a critically ill neonatal population, and the results indicate that the optical technology is a promising clinical method for monitoring this population. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
29. Diffuse optical monitoring of blood flow and oxygenation in human breast cancer during early stages of neoadjuvant chemotherapy.
- Author
-
Chao Zhou, Regine Choe, Natasha Shah, Turgut Durduran, Guoqiang Yu, Amanda Durkin, David Hsiang, Rita Mehta, John Butler, Albert Cerussi, Bruce J. Tromberg, and Arjun G. Yodh
- Subjects
DRUG therapy ,BREAST cancer ,BLOOD flow measurement ,OXYGENATORS - Abstract
We combine diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS) to noninvasively monitor early hemodynamic response to neoadjuvant chemotherapy in a breast cancer patient. The potential for early treatment monitoring is demonstrated. Within the first week of treatment (day 7) DOS revealed significant changes in tumor/normal contrast compared to pretreatment (day 0) tissue concentrations of deoxyhemoglobin (rctHHbT/N=69±21%), oxyhemoglobin (rctO2HbT/N=73±25%), total hemoglobin (rctTHbT/N=72±17%), and lipid concentration (rctLipidT/N=116±13%). Similarly, DCS found significant changes in tumor/normal blood flow contrast (rBFT/N=75±7% on day 7 with respect to day 0). Our observations suggest the combination of DCS and DOS enhances treatment monitoring compared to either technique alone. The hybrid approach also enables construction of indices reflecting tissue metabolic rate of oxygen, which may provide new insights about therapy mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
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