101
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Diop M, Kishimoto J, Toronov V, Lee DSC, St. Lawrence K. Development of a combined broadband near-infrared and diffusion correlation system for monitoring cerebral blood flow and oxidative metabolism in preterm infants. BIOMEDICAL OPTICS EXPRESS 2015; 6:3907-18. [PMID: 26504641 PMCID: PMC4605050 DOI: 10.1364/boe.6.003907] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 05/23/2023]
Abstract
Neonatal neuromonitoring is a major clinical focus of near-infrared spectroscopy (NIRS) and there is an increasing interest in measuring cerebral blood flow (CBF) and oxidative metabolism (CMRO2) in addition to the classic tissue oxygenation saturation (StO2). The purpose of this study was to assess the ability of broadband NIRS combined with diffusion correlation spectroscopy (DCS) to measured changes in StO2, CBF and CMRO2 in preterm infants undergoing pharmaceutical treatment of patent ductus arteriosus. CBF was measured by both DCS and contrast-enhanced NIRS for comparison. No significant difference in the treatment-induced CBF decrease was found between DCS (27.9 ± 2.2%) and NIRS (26.5 ± 4.3%). A reduction in StO2 (70.5 ± 2.4% to 63.7 ± 2.9%) was measured by broadband NIRS, reflecting the increase in oxygen extraction required to maintain CMRO2. This study demonstrates the applicability of broadband NIRS combined with DCS for neuromonitoring in this patient population.
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Affiliation(s)
- Mamadou Diop
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Jessica Kishimoto
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | | | - David S. C. Lee
- Department of Neonatology, London Health Sciences Centre, London, ON, Canada
| | - Keith St. Lawrence
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
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102
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Chen C, Florian K, Rajesh K, Max R, Christian K, Florian S, Michael S. Recovering the superficial microvascular pattern via diffuse reflection imaging: phantom validation. Biomed Eng Online 2015; 14:87. [PMID: 26419826 PMCID: PMC4589028 DOI: 10.1186/s12938-015-0081-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 09/03/2015] [Indexed: 11/26/2022] Open
Abstract
Background Diffuse reflection imaging could potentially be used to recover the superficial microvasculature under cutaneous tissue and the associated blood oxygenation status with a modified imaging resolution. The aim of this work is to deliver a new approach of local off-axis scanning diffuse reflection imaging, with the revisit of the modified Beer–Lambert Law (MBLL). Methods To validate this, the system is used to recover the micron-scale subsurface vessel structure interiorly embedded in a skin equivalent tissue phantom. This vessel structure is perfused with oxygenated meta-hemoglobin solution. Results Our preliminary results confirm that the thin vessel structure can be mapped into a 2-D planar image. The distributions of oxygenated hemoglobin concentration (\documentclass[12pt]{minimal}
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\begin{document}$$Ct_{HbO_{2}}$$\end{document}CtHbO2) and deoxygenated hemoglobin concentration (\documentclass[12pt]{minimal}
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\begin{document}$$Ct_{RHb}$$\end{document}CtRHb) can be co-registerated through the MBLL upon the CW spectroscopy, the scattering issue is addressed in the reformed MBLL. The recovered pattern matches to the estimation from the simultaneous optical coherence tomography studies. Conclusions With further modification, this system may serve as the first prototype to investigate the superficial microvasculature in the expotential skin cancer loci, or a micro-lesion of vascular dermatosis.
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Affiliation(s)
- Chen Chen
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
| | - Klämpfl Florian
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany.
| | - Kanawade Rajesh
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
| | - Riemann Max
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Knipfer Christian
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Stelzle Florian
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glück Str. 11, 91054, Erlangen, Germany.
| | - Schmidt Michael
- Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052, Erlangen, Germany. .,Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052, Erlangen, Germany.
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103
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Han S, Johansson J, Mireles M, Proctor AR, Hoffman MD, Vella JB, Benoit DSW, Durduran T, Choe R. Non-contact scanning diffuse correlation tomography system for three-dimensional blood flow imaging in a murine bone graft model. BIOMEDICAL OPTICS EXPRESS 2015; 6. [PMID: 26203392 PMCID: PMC4505720 DOI: 10.1364/boe.6.002695] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A non-contact galvanometer-based optical scanning system for diffuse correlation tomography was developed for monitoring bone graft healing in a murine femur model. A linear image reconstruction algorithm for diffuse correlation tomography was tested using finite-element method based simulated data and experimental data from a femur or a tube suspended in a homogeneous liquid phantom. Finally, the non-contact system was utilized to monitor in vivo blood flow changes prior to and one week after bone graft transplantation within murine femurs. Localized blood flow changes were observed in three mice, demonstrating a potential for quantification of longitudinal blood flow associated with bone graft healing.
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Affiliation(s)
- Songfeng Han
- Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - Johannes Johansson
- ICFO- Institut de Ciències Fotòniques, 08860, Castelldefels (Barcelona), Spain
| | - Miguel Mireles
- ICFO- Institut de Ciències Fotòniques, 08860, Castelldefels (Barcelona), Spain
| | - Ashley R. Proctor
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Michael D. Hoffman
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Joseph B. Vella
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, USA
- Department of Otolaryngology-Head and Neck Surgery, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Danielle S. W. Benoit
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, USA
- Department of Chemical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Turgut Durduran
- ICFO- Institut de Ciències Fotòniques, 08860, Castelldefels (Barcelona), Spain
| | - Regine Choe
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627, USA
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104
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Liu P, Dimitrov I, Andrews T, Crane DE, Dariotis JK, Desmond J, Dumas J, Gilbert G, Kumar A, Maclntosh BJ, Tucholka A, Yang S, Xiao G, Lu H. Multisite evaluations of a T2 -relaxation-under-spin-tagging (TRUST) MRI technique to measure brain oxygenation. Magn Reson Med 2015; 75:680-7. [PMID: 25845468 DOI: 10.1002/mrm.25627] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/19/2014] [Accepted: 01/02/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE Venous oxygenation (Yv ) is an important index of brain physiology and may be indicative of brain diseases. A T2 -relaxation-under-spin-tagging (TRUST) MRI technique was recently developed to measure Yv . A multisite evaluation of this technique would be an important step toward broader availability and potential clinical utilizations of Yv measures. METHODS TRUST MRI was performed on a total of 250 healthy subjects, 125 from the developer's site and 25 each from five other sites. All sites were equipped with a 3 Tesla (T) MRI of the same vendor. The estimated Yv and the standard error (SE) of the estimation εYv were compared across sites. RESULTS The averaged Yv and εYv across six sites were 61.1% ± 1.4% and 1.3% ± 0.2%, respectively. Multivariate regression analysis showed that the estimated Yv was dependent on age (P = 0.009) but not on performance site. In contrast, the SE of the Yv estimation was site-dependent (P = 0.024) but was less than 1.5%. Further analysis revealed that εYv was positively associated with the amount of subject motion (P < 0.001) but negatively associated with blood signal intensity (P < 0.001). CONCLUSION This work suggests that TRUST MRI can yield equivalent results of Yv estimation across different sites.
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Affiliation(s)
- Peiying Liu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ivan Dimitrov
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,MR clinical science, Philips Healthcare, Cleveland, Ohio, USA
| | - Trevor Andrews
- MR clinical science, Philips Healthcare, Cleveland, Ohio, USA.,Department of Radiology, University of Vermont College of Medicine, Burlington, Vermont, USA
| | - David E Crane
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Jacinda K Dariotis
- Department of Population, Family and Reproductive Health, Center for Adolescent Health, The Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - John Desmond
- Department of Neurology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Julie Dumas
- Department of Psychiatry, University of Vermont College of Medicine, Burlington, Vermont, USA
| | - Guillaume Gilbert
- MR clinical science, Philips Healthcare, Cleveland, Ohio, USA.,Department of Radiology, Notre-Dame Hospital, University of Montreal, Montreal, QC, Canada
| | - Anand Kumar
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Bradley J Maclntosh
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Alan Tucholka
- Department of Radiology, Notre-Dame Hospital, University of Montreal, Montreal, QC, Canada
| | - Shaolin Yang
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Guanghua Xiao
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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105
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Continuous optical monitoring of cerebral hemodynamics during head-of-bed manipulation in brain-injured adults. Neurocrit Care 2015; 20:443-53. [PMID: 23653267 DOI: 10.1007/s12028-013-9849-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Head-of-bed manipulation is commonly performed in the neurocritical care unit to optimize cerebral blood flow (CBF), but its effects on CBF are rarely measured. This pilot study employs a novel, non-invasive instrument combining two techniques, diffuse correlation spectroscopy (DCS) for measurement of CBF and near-infrared spectroscopy (NIRS) for measurement of cerebral oxy- and deoxy-hemoglobin concentrations, to monitor patients during head-of-bed lowering. METHODS Ten brain-injured patients and ten control subjects were monitored continuously with DCS and NIRS while the head-of-bed was positioned first at 30° and then at 0°. Relative CBF (rCBF) and concurrent changes in oxy- (ΔHbO2), deoxy- (ΔHb), and total-hemoglobin concentrations (ΔTHC) from left/right frontal cortices were monitored for 5 min at each position. Patient and control response differences were assessed. RESULTS rCBF, ΔHbO2, and ΔTHC responses to head lowering differed significantly between brain-injured patients and healthy controls (P < 0.02). For patients, rCBF changes were heterogeneous, with no net change observed in the group average (0.3 ± 28.2 %, P = 0.938). rCBF increased in controls (18.6 ± 9.4 %, P < 0.001). ΔHbO2, ΔHb, and ΔTHC increased with head lowering in both groups, but to a larger degree in brain-injured patients. rCBF correlated moderately with changes in cerebral perfusion pressure (R = 0.40, P < 0.001), but not intracranial pressure. CONCLUSION DCS/NIRS detected differences in CBF and oxygenation responses of brain-injured patients versus controls during head-of-bed manipulation. This pilot study supports the feasibility of continuous bedside measurement of cerebrovascular hemodynamics with DCS/NIRS and provides the rationale for further investigation in larger cohorts.
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106
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Liu P, Chalak LF, Lu H. Non-invasive assessment of neonatal brain oxygen metabolism: A review of newly available techniques. Early Hum Dev 2014; 90:695-701. [PMID: 25028136 PMCID: PMC4170025 DOI: 10.1016/j.earlhumdev.2014.06.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 06/23/2014] [Indexed: 11/28/2022]
Abstract
Because oxidative metabolism is the primary form of energy production in the brain, the amount of oxygen consumed by the brain, denoted by a physiological parameter termed cerebral metabolic rate of oxygen (CMRO2), represents a key marker for tissue viability and brain function. Quantitative assessment of cerebral oxygen metabolism in the neonate may provide an important marker in better understanding normal brain development and in making diagnosis and treatment decisions in neonatal brain injuries. Measurement of CMRO2 in humans has been a challenging task, particularly in neonates. Recently, several promising techniques have been proposed to quantify neonatal CMRO2 and the purpose of this article is to provide a technical review of these techniques. Among these, we will focus the review on the NIRS optic based methods and MRI methods which are non-invasive, have been applied in normal and sick newborns and show great potentials. Potential clinical prospects of CMRO2 techniques are discussed in the context of their advantages, challenges and limitations.
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Affiliation(s)
- Peiying Liu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States.
| | - Lina F Chalak
- Depart of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States.
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States.
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107
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Jadcherla SR, Pakiraih JF, Hasenstab KA, Dar I, Gao X, Bates DG, Kashou NH. Esophageal reflexes modulate frontoparietal response in neonates: Novel application of concurrent NIRS and provocative esophageal manometry. Am J Physiol Gastrointest Liver Physiol 2014; 307:G41-9. [PMID: 24789204 PMCID: PMC4080167 DOI: 10.1152/ajpgi.00350.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Central and peripheral neural regulation of swallowing and aerodigestive reflexes is unclear in human neonates. Functional near infrared spectroscopy (NIRS) is a noninvasive method to measure changes in oxyhemoglobin (HbO) and deoxyhemoglobin (HbD). Pharyngoesophageal manometry permits evaluation of aerodigestive reflexes. Modalities were combined to investigate feasibility and to test neonatal frontoparietal cortical changes during pharyngoesophageal (visceral) stimulation and/or swallowing. Ten neonates (45.6 ± 3.0 wk postmenstrual age, 4.1 ± 0.5 kg) underwent novel pharyngoesophageal manometry concurrent with NIRS. To examine esophagus-brain interactions, we analyzed cortical hemodynamic response (HDR) latency and durations during aerodigestive provocation and esophageal reflexes. Data are presented as means ± SE or percent. HDR rates were 8.84 times more likely with basal spontaneous deglutition compared with sham stimuli (P = 0.004). Of 182 visceral stimuli, 95% were analyzable for esophageal responses, 38% for HDR, and 36% for both. Of analyzable HDR (n = 70): 1) HbO concentration (μmol/l) baseline 1.5 ± 0.7 vs. 3.7 ± 0.7 poststimulus was significant (P = 0.02), 2) HbD concentration (μmol/l) between baseline 0.1 ± 0.4 vs. poststimulus -0.5 ± 0.4 was not significant (P = 0.73), and 3) hemispheric lateralization was 21% left only, 29% right only, and 50% bilateral. During concurrent esophageal and NIRS responses (n = 66): 1) peristaltic reflexes were present in 74% and HDR in 61% and 2) HDR was 4.75 times more likely with deglutition reflex vs. secondary peristaltic reflex (P = 0.016). Concurrent NIRS with visceral stimulation is feasible in neonates, and frontoparietal cortical activation is recognized. Deglutition contrasting with secondary peristalsis is related to cortical activation, thus implicating higher hierarchical aerodigestive protective functional neural networks.
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Affiliation(s)
- Sudarshan R. Jadcherla
- 1Divisions of Neonatology and Pediatric Gastroenterology and Nutrition, Nationwide Children's Hospital, Columbus, Ohio; ,2Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio; ,3Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio;
| | - Joanna F. Pakiraih
- 2Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio; ,5Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio
| | - Kathryn A. Hasenstab
- 2Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio;
| | - Irfaan Dar
- 2Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio; ,4Biomedical, Industrial & Human Factors Engineering, Wright State University, Ohio; and
| | - Xiaoyu Gao
- 2Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio;
| | - D. Gregory Bates
- 3Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio; ,5Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio
| | - Nasser H. Kashou
- 4Biomedical, Industrial & Human Factors Engineering, Wright State University, Ohio; and
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108
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Lynch JM, Buckley EM, Schwab PJ, McCarthy AL, Winters ME, Busch DR, Xiao R, Goff DA, Nicolson SC, Montenegro LM, Fuller S, Gaynor JW, Spray TL, Yodh AG, Naim MY, Licht DJ. Time to surgery and preoperative cerebral hemodynamics predict postoperative white matter injury in neonates with hypoplastic left heart syndrome. J Thorac Cardiovasc Surg 2014; 148:2181-8. [PMID: 25109755 DOI: 10.1016/j.jtcvs.2014.05.081] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 05/12/2014] [Accepted: 05/29/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Hypoxic-ischemic white mater brain injury commonly occurs in neonates with hypoplastic left heart syndrome (HLHS). Approximately one half of HLHS survivors will exhibit neurobehavioral symptoms believed to be associated with this injury, although the exact timing of the injury is unknown. METHODS Neonates with HLHS were recruited for pre- and postoperative monitoring of cerebral oxygen saturation, cerebral oxygen extraction fraction, and cerebral blood flow using 2 noninvasive optical-based techniques: diffuse optical spectroscopy and diffuse correlation spectroscopy. Anatomic magnetic resonance imaging was performed before and approximately 1 week after surgery to quantify the extent and timing of the acquired white matter injury. The risk factors for developing new or worsened white matter injury were assessed using uni- and multivariate logistic regression. RESULTS A total of 37 neonates with HLHS were studied. On univariate analysis, neonates who developed a large volume of new, or worsened, postoperative white matter injury had a significantly longer time to surgery (P=.0003). In a multivariate model, a longer time between birth and surgery, delayed sternal closure, and greater preoperative cerebral blood flow were predictors of postoperative white matter injury. Additionally, a longer time to surgery and greater preoperative cerebral blood flow on the morning of surgery correlated with lower cerebral oxygen saturation (P=.03 and P=.05, respectively) and greater oxygen extraction fraction (P=.05 for both). CONCLUSIONS A longer time to surgery was associated with new postoperative white matter injury in otherwise healthy neonates with HLHS. The results suggest that earlier Norwood palliation might decrease the likelihood of acquiring postoperative white matter injury.
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Affiliation(s)
- Jennifer M Lynch
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pa.
| | - Erin M Buckley
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pa; Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Massachusetts General Hospital, Charlestown, Mass; Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Peter J Schwab
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Ann L McCarthy
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Madeline E Winters
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - David R Busch
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Rui Xiao
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pa
| | - Donna A Goff
- Division of Pediatric Cardiology, Loma Linda University Children's Hospital, Loma Linda, Calif
| | - Susan C Nicolson
- Division of Cardiothoracic Anesthesia, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Lisa M Montenegro
- Division of Cardiothoracic Anesthesia, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Stephanie Fuller
- Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - J William Gaynor
- Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Thomas L Spray
- Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pa
| | - Maryam Y Naim
- Division of Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Daniel J Licht
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pa
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109
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Buckley EM, Parthasarathy AB, Grant PE, Yodh AG, Franceschini MA. Diffuse correlation spectroscopy for measurement of cerebral blood flow: future prospects. NEUROPHOTONICS 2014; 1:011009. [PMID: 25593978 PMCID: PMC4292799 DOI: 10.1117/1.nph.1.1.011009] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Diffuse correlation spectroscopy (DCS) is an emerging optical modality used to measure cortical cerebral blood flow. This outlook presents a brief overview of the technology, summarizing the advantages and limitations of the method, and describing its recent applications to animal, adult, and infant cohorts. At last, the paper highlights future applications where DCS may play a pivotal role individualizing patient management and enhancing our understanding of neurovascular coupling, activation, and brain development.
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Affiliation(s)
- Erin M. Buckley
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts 02129
- Address all correspondence to: Erin M. Buckley,
| | - Ashwin B. Parthasarathy
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania 19104
| | - P. Ellen Grant
- Boston Children’s Hospital, Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston, Massachusetts 02115
| | - Arjun G. Yodh
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania 19104
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts 02129
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110
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Jain V, Buckley EM, Licht DJ, Lynch JM, Schwab PJ, Naim MY, Lavin NA, Nicolson SC, Montenegro LM, Yodh AG, Wehrli FW. Cerebral oxygen metabolism in neonates with congenital heart disease quantified by MRI and optics. J Cereb Blood Flow Metab 2014; 34:380-8. [PMID: 24326385 PMCID: PMC3948119 DOI: 10.1038/jcbfm.2013.214] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/30/2013] [Accepted: 11/04/2013] [Indexed: 11/09/2022]
Abstract
Neonatal congenital heart disease (CHD) is associated with altered cerebral hemodynamics and increased risk of brain injury. Two novel noninvasive techniques, magnetic resonance imaging (MRI) and diffuse optical and correlation spectroscopies (diffuse optical spectroscopy (DOS), diffuse correlation spectroscopy (DCS)), were employed to quantify cerebral blood flow (CBF) and oxygen metabolism (CMRO(2)) of 32 anesthetized CHD neonates at rest and during hypercapnia. Cerebral venous oxygen saturation (S(v)O(2)) and CBF were measured simultaneously with MRI in the superior sagittal sinus, yielding global oxygen extraction fraction (OEF) and global CMRO(2) in physiologic units. In addition, microvascular tissue oxygenation (StO(2)) and indices of microvascular CBF (BFI) and CMRO(2) (CMRO(2)(i)) in the frontal cortex were determined by DOS/DCS. Median resting-state MRI-measured OEF, CBF, and CMRO(2) were 0.38, 9.7 mL/minute per 100 g and 0.52 mL O(2)/minute per 100 g, respectively. These CBF and CMRO(2) values are lower than literature reports for healthy term neonates (which are sparse and quantified using different methods) and resemble values reported for premature infants. Comparison of MRI measurements of global S(v)O(2), CBF, and CMRO(2) with corresponding local DOS/DCS measurements demonstrated strong linear correlations (R(2)=0.69, 0.67, 0.67; P<0.001), permitting calibration of DOS/DCS indices. The results suggest that MRI and optics offer new tools to evaluate cerebral hemodynamics and metabolism in CHD neonates.
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Affiliation(s)
- Varsha Jain
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
| | - Erin M Buckley
- 1] Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA [2] Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel J Licht
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jennifer M Lynch
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Peter J Schwab
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Maryam Y Naim
- Division of Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Natasha A Lavin
- Division of Respiratory Therapy, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Susan C Nicolson
- Division of Cardiothoracic Anesthesia, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Lisa M Montenegro
- Division of Cardiothoracic Anesthesia, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
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111
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Busch DR, Choe R, Durduran T, Friedman DH, Baker WB, Maidment AD, Rosen MA, Schnall MD, Yodh AG. Blood flow reduction in breast tissue due to mammographic compression. Acad Radiol 2014; 21:151-61. [PMID: 24439328 DOI: 10.1016/j.acra.2013.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 10/08/2013] [Accepted: 10/14/2013] [Indexed: 10/25/2022]
Abstract
RATIONALE AND OBJECTIVES This study measures hemodynamic properties such as blood flow and hemoglobin concentration and oxygenation in the healthy human breast under a wide range of compressive loads. Because many breast-imaging technologies derive contrast from the deformed breast, these load-dependent vascular responses affect contrast agent-enhanced and hemoglobin-based breast imaging. METHODS Diffuse optical and diffuse correlation spectroscopies were used to measure the concentrations of oxygenated and deoxygenated hemoglobin, lipid, water, and microvascular blood flow during axial breast compression in the parallel-plate transmission geometry. RESULTS Significant reductions (P < .01) in total hemoglobin concentration (∼30%), blood oxygenation (∼20%), and blood flow (∼87%) were observed under applied pressures (forces) of up to 30 kPa (120 N) in 15 subjects. Lipid and water concentrations changed <10%. CONCLUSIONS Imaging protocols based on injected contrast agents should account for variation in tissue blood flow due to mammographic compression. Similarly, imaging techniques that depend on endogenous blood contrasts will be affected by breast compression during imaging.
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Durduran T, Yodh AG. Diffuse correlation spectroscopy for non-invasive, micro-vascular cerebral blood flow measurement. Neuroimage 2014; 85 Pt 1:51-63. [PMID: 23770408 PMCID: PMC3991554 DOI: 10.1016/j.neuroimage.2013.06.017] [Citation(s) in RCA: 299] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 05/10/2013] [Accepted: 06/06/2013] [Indexed: 12/25/2022] Open
Abstract
Diffuse correlation spectroscopy (DCS) uses the temporal fluctuations of near-infrared (NIR) light to measure cerebral blood flow (CBF) non-invasively. Here, we provide a brief history of DCS applications in the brain with an emphasis on the underlying physical ideas, common instrumentation and validation. Then we describe recent clinical research that employs DCS-measured CBF as a biomarker of patient well-being, and as an indicator of hemodynamic and metabolic responses to functional stimuli.
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Affiliation(s)
- Turgut Durduran
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain.
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113
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Cerebral oxygen metabolism in neonatal hypoxic ischemic encephalopathy during and after therapeutic hypothermia. J Cereb Blood Flow Metab 2014; 34:87-94. [PMID: 24064492 PMCID: PMC3887346 DOI: 10.1038/jcbfm.2013.165] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/15/2013] [Accepted: 08/26/2013] [Indexed: 11/09/2022]
Abstract
Pathophysiologic mechanisms involved in neonatal hypoxic ischemic encephalopathy (HIE) are associated with complex changes of blood flow and metabolism. Therapeutic hypothermia (TH) is effective in reducing the extent of brain injury, but it remains uncertain how TH affects cerebral blood flow (CBF) and metabolism. Ten neonates undergoing TH for HIE and seventeen healthy controls were recruited from the NICU and the well baby nursery, respectively. A combination of frequency domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) systems was used to non-invasively measure cerebral hemodynamic and metabolic variables at the bedside. Results showed that cerebral oxygen metabolism (CMRO2i) and CBF indices (CBFi) in neonates with HIE during TH were significantly lower than post-TH and age-matched control values. Also, cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) were significantly higher in neonates with HIE during TH compared with age-matched control neonates. Post-TH CBV was significantly decreased compared with values during TH whereas SO2 remained unchanged after the therapy. Thus, FDNIRS-DCS can provide information complimentary to SO2 and can assess individual cerebral metabolic responses to TH. Combined FDNIRS-DCS parameters improve the understanding of the underlying physiology and have the potential to serve as bedside biomarkers of treatment response and optimization.
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114
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Sodium bicarbonate causes dose-dependent increases in cerebral blood flow in infants and children with single-ventricle physiology. Pediatr Res 2013; 73:668-73. [PMID: 23403802 PMCID: PMC3724528 DOI: 10.1038/pr.2013.25] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Sodium bicarbonate (NaHCO3) is a common treatment for metabolic acidemia; however, little definitive information exists regarding its treatment efficacy and cerebral hemodynamic effects. This pilot observational study quantifies relative changes in cerebral blood flow (ΔrCBF) and oxy- and deoxyhemoglobin concentrations (ΔHbO2 and ΔHb) due to bolus administration of NaHCO3 in patients with mild base deficits. METHODS Infants and children with hypoplastic left heart syndrome (HLHS) were enrolled before cardiac surgery. NaHCO3 was given as needed for treatment of base deficit. Diffuse optical spectroscopies were used for 15 min postinjection to noninvasively monitor ΔHb, ΔHbO2, and ΔrCBF relative to baseline before NaHCO3 administration. RESULTS Twenty-two anesthetized and mechanically ventilated patients with HLHS (aged 1 d to 4 y) received a median (interquartile range) dose of 1.1 (0.8, 1.8) mEq/kg NaHCO3 administered intravenously over 10-20 s to treat a median (interquartile range) base deficit of -4 (-6, -3) mEq/l. NaHCO3 caused significant dose-dependent increases in ΔrCBF; however, population-averaged ΔHb and ΔHbO2 as compared with those of controls were not significant. CONCLUSIONS Dose-dependent increases in cerebral blood flow (CBF) caused by bolus administration of NaHCO3 are an important consideration in vulnerable populations wherein risk of rapid CBF fluctuations does not outweigh the benefit of treating a base deficit.
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Lin PY, Roche-Labarbe N, Dehaes M, Carp S, Fenoglio A, Barbieri B, Hagan K, Grant PE, Franceschini MA. Non-invasive optical measurement of cerebral metabolism and hemodynamics in infants. J Vis Exp 2013:e4379. [PMID: 23524854 PMCID: PMC3639513 DOI: 10.3791/4379] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Perinatal brain injury remains a significant cause of infant mortality and morbidity, but there is not yet an effective bedside tool that can accurately screen for brain injury, monitor injury evolution, or assess response to therapy. The energy used by neurons is derived largely from tissue oxidative metabolism, and neural hyperactivity and cell death are reflected by corresponding changes in cerebral oxygen metabolism (CMRO2). Thus, measures of CMRO2 are reflective of neuronal viability and provide critical diagnostic information, making CMRO2 an ideal target for bedside measurement of brain health. Brain-imaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) yield measures of cerebral glucose and oxygen metabolism, but these techniques require the administration of radionucleotides, so they are used in only the most acute cases. Continuous-wave near-infrared spectroscopy (CWNIRS) provides non-invasive and non-ionizing radiation measures of hemoglobin oxygen saturation (SO2) as a surrogate for cerebral oxygen consumption. However, SO2 is less than ideal as a surrogate for cerebral oxygen metabolism as it is influenced by both oxygen delivery and consumption. Furthermore, measurements of SO2 are not sensitive enough to detect brain injury hours after the insult 1,2, because oxygen consumption and delivery reach equilibrium after acute transients3. We investigated the possibility of using more sophisticated NIRS optical methods to quantify cerebral oxygen metabolism at the bedside in healthy and brain-injured newborns. More specifically, we combined the frequency-domain NIRS (FDNIRS) measure of SO2 with the diffuse correlation spectroscopy (DCS) measure of blood flow index (CBFi) to yield an index of CMRO2 (CMRO2i) 4,5. With the combined FDNIRS/DCS system we are able to quantify cerebral metabolism and hemodynamics. This represents an improvement over CWNIRS for detecting brain health, brain development, and response to therapy in neonates. Moreover, this method adheres to all neonatal intensive care unit (NICU) policies on infection control and institutional policies on laser safety. Future work will seek to integrate the two instruments to reduce acquisition time at the bedside and to implement real-time feedback on data quality to reduce the rate of data rejection.
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Affiliation(s)
- Pei-Yi Lin
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, USA.
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Roche-Labarbe N, Fenoglio A, Radhakrishnan H, Kocienski-Filip M, Carp SA, Dubb J, Boas DA, Grant PE, Franceschini MA. Somatosensory evoked changes in cerebral oxygen consumption measured non-invasively in premature neonates. Neuroimage 2013; 85 Pt 1:279-86. [PMID: 23370052 DOI: 10.1016/j.neuroimage.2013.01.035] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/16/2013] [Accepted: 01/22/2013] [Indexed: 12/20/2022] Open
Abstract
The hemodynamic functional response is used as a reliable marker of neuronal activity in countless studies of brain function and cognition. In newborns and infants, however, conflicting results have appeared in the literature concerning the typical response, and there is little information on brain metabolism and functional activation. Measurement of all hemodynamic components and oxygen metabolism is critical for understanding neurovascular coupling in the developing brain. To this end, we combined multiple near infrared spectroscopy techniques to measure oxy- and deoxy-hemoglobin concentrations, cerebral blood volume (CBV), and relative cerebral blood flow (CBF) in the somatosensory cortex of 6 preterm neonates during passive tactile stimulation of the hand. By combining these measures we estimated relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2). CBF starts increasing immediately after stimulus onset, and returns to baseline before blood volume. This is consistent with the model of pre-capillary arteriole active dilation driving the CBF response, with a subsequent CBV increase influenced by capillaries and veins dilating passively to accommodate the extra blood. rCMRO2 estimated using the steady-state formulation shows a biphasic pattern: an increase immediately after stimulus onset, followed by a post-stimulus undershoot due to blood flow returning faster to baseline than oxygenation. However, assuming a longer mean transit time from the arterial to the venous compartment, due to the immature vascular system of premature infants, reduces the post-stimulus undershoot and increases the flow/consumption ratio to values closer to adult values reported in the literature. We are the first to report changes in local rCBF and rCMRO2 during functional activation in preterm infants. The ability to measure these variables in addition to hemoglobin concentration changes is critical for understanding neurovascular coupling in the developing brain, and for using this coupling as a reliable functional imaging marker in neonates.
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Affiliation(s)
- Nadege Roche-Labarbe
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Laboratoire Psychologie des Actions Langagières et Motrices, Université de Caen Basse-Normandie, France.
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117
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Shang Y, Gurley K, Yu G. Diffuse Correlation Spectroscopy (DCS) for Assessment of Tissue Blood Flow in Skeletal Muscle: Recent Progress. ACTA ACUST UNITED AC 2013; 3:128. [PMID: 24724043 PMCID: PMC3979478 DOI: 10.4172/2161-0940.1000128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Near-infrared diffuse correlation spectroscopy (DCS) is an emerging technology for monitoring blood flow in various tissues. This article reviews the recent progress of DCS for the assessment of skeletal muscle blood flow, including the developments in technology allowing use during dynamic exercise and muscular electrical stimulation, the utilization for diagnosis of muscle vascular diseases, and the applications for evaluating treatment effects. The limitations of current DCS studies and future perspective are finally discussed.
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Affiliation(s)
- Yu Shang
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Katelyn Gurley
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA ; Department of Neurological Surgery, University of Louisville, Louisville, KY 40202, USA
| | - Guoqiang Yu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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118
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Buckley EM, Lynch JM, Goff DA, Schwab PJ, Baker WB, Durduran T, Busch DR, Nicolson SC, Montenegro LM, Naim MY, Xiao R, Spray TL, Yodh AG, Gaynor JW, Licht DJ. Early postoperative changes in cerebral oxygen metabolism following neonatal cardiac surgery: effects of surgical duration. J Thorac Cardiovasc Surg 2012; 145:196-203, 205.e1; discussion 203-5. [PMID: 23111021 DOI: 10.1016/j.jtcvs.2012.09.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/21/2012] [Accepted: 09/21/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE The early postoperative period following neonatal cardiac surgery is a time of increased risk for brain injury, yet the mechanisms underlying this risk are unknown. To understand these risks more completely, we quantified changes in postoperative cerebral metabolic rate of oxygen (CMRO(2)), oxygen extraction fraction (OEF), and cerebral blood flow (CBF) compared with preoperative levels by using noninvasive optical modalities. METHODS Diffuse optical spectroscopy and diffuse correlation spectroscopy were used concurrently to derive cerebral blood flow and oxygen utilization postoperatively for 12 hours. Relative changes in CMRO(2), OEF, and CBF were quantified with reference to preoperative data. A mixed-effect model was used to investigate the influence of total support time and deep hypothermic circulatory arrest duration on relative changes in CMRO(2), OEF, and CBF. RESULTS Relative changes in CMRO(2), OEF, and CBF were assessed in 36 patients, 21 with single-ventricle defects and 15 with 2-ventricle defects. Among patients with single-ventricle lesions, deep hypothermic circulatory arrest duration did not affect relative changes in CMRO(2), CBF, or OEF (P > .05). Among 2-ventricle patients, total support time was not a significant predictor of relative changes in CMRO(2) or CBF (P > .05), although longer total support time was associated significantly with greater increases in relative change of postoperative OEF (P = .008). CONCLUSIONS Noninvasive diffuse optical techniques were used to quantify postoperative relative changes in CMRO(2), CBF, and OEF for the first time in this observational pilot study. Pilot data suggest that surgical duration does not account for observed variability in the relative change in CMRO(2), and that more comprehensive clinical studies using the new technology are feasible and warranted to elucidate these issues further.
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Affiliation(s)
- Erin M Buckley
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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119
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Lückl J, Dreier JP, Szabados T, Wiesenthal D, Bari F, Greenberg JH. Peri-infarct flow transients predict outcome in rat focal brain ischemia. Neuroscience 2012; 226:197-207. [PMID: 22986160 DOI: 10.1016/j.neuroscience.2012.08.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/10/2012] [Accepted: 08/23/2012] [Indexed: 01/09/2023]
Abstract
Spreading depolarizations are accompanied by transient changes in cerebral blood flow (CBF). In a post hoc analysis of previously studied control rats we analyzed CBF time courses after middle cerebral artery occlusion in the rat in order to test whether intra-ischemic flow, reperfusion, and different parameters of peri-infarct flow transients (PIFTs) (amplitude, number) can predict outcome. Sprague-Dawley rats anesthetized with either halothane (n=23) or isoflurane (n=32) underwent 90-min filament occlusion of the middle cerebral artery followed by 72 h of reperfusion. The infarct size was determined by 2,3,5-triphenyltetrazolium chloride staining. Relative CBF changes were monitored by laser Doppler flowmetry at 4-5 mm lateral, and 1-2mm posterior to Bregma. An additional filament occlusion study (n=12) was performed to validate that PIFTs were coupled to direct current shifts of spreading depolarization. The PIFT-direct current shift study revealed that every PIFT was associated with a negative direct current shift typical of spreading depolarization. Post-hoc analysis showed that the number of PIFTs, especially with the combination of intra-ischemic level of flow, can predict the development of cortical infarcts. These findings show that PIFTs can serve as an early biomarker in predicting outcome in preclinical animal studies.
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Affiliation(s)
- J Lückl
- Department of Neurology, University of Pennsylvania, 415 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6063, USA
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120
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Cheng R, Shang Y, Hayes D, Saha SP, Yu G. Noninvasive optical evaluation of spontaneous low frequency oscillations in cerebral hemodynamics. Neuroimage 2012; 62:1445-54. [DOI: 10.1016/j.neuroimage.2012.05.069] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/11/2012] [Accepted: 05/24/2012] [Indexed: 01/15/2023] Open
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121
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Devor A, Sakadžić S, Srinivasan VJ, Yaseen MA, Nizar K, Saisan PA, Tian P, Dale AM, Vinogradov SA, Franceschini MA, Boas DA. Frontiers in optical imaging of cerebral blood flow and metabolism. J Cereb Blood Flow Metab 2012; 32:1259-76. [PMID: 22252238 PMCID: PMC3390808 DOI: 10.1038/jcbfm.2011.195] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In vivo optical imaging of cerebral blood flow (CBF) and metabolism did not exist 50 years ago. While point optical fluorescence and absorption measurements of cellular metabolism and hemoglobin concentrations had already been introduced by then, point blood flow measurements appeared only 40 years ago. The advent of digital cameras has significantly advanced two-dimensional optical imaging of neuronal, metabolic, vascular, and hemodynamic signals. More recently, advanced laser sources have enabled a variety of novel three-dimensional high-spatial-resolution imaging approaches. Combined, as we discuss here, these methods are permitting a multifaceted investigation of the local regulation of CBF and metabolism with unprecedented spatial and temporal resolution. Through multimodal combination of these optical techniques with genetic methods of encoding optical reporter and actuator proteins, the future is bright for solving the mysteries of neurometabolic and neurovascular coupling and translating them to clinical utility.
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Affiliation(s)
- Anna Devor
- Department of Neurosciences, UCSD, La Jolla, CA, USA.
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122
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Buckley EM, Hance D, Pawlowski T, Lynch J, Wilson FB, Mesquita RC, Durduran T, Diaz LK, Putt ME, Licht DJ, Fogel MA, Yodh AG. Validation of diffuse correlation spectroscopic measurement of cerebral blood flow using phase-encoded velocity mapping magnetic resonance imaging. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:037007. [PMID: 22502579 PMCID: PMC3380925 DOI: 10.1117/1.jbo.17.3.037007] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Diffuse correlation spectroscopy (DCS) is a novel optical technique that appears to be an excellent tool for assessing cerebral blood flow in a continuous and non-invasive manner at the bedside. We present new clinical validation of the DCS methodology by demonstrating strong agreement between DCS indices of relative cerebral blood flow and indices based on phase-encoded velocity mapping magnetic resonance imaging (VENC MRI) of relative blood flow in the jugular veins and superior vena cava. Data were acquired from 46 children with single ventricle cardiac lesions during a hypercapnia intervention. Significant increases in cerebral blood flow, measured both by DCS and by VENC MRI, as well as significant increases in oxyhemoglobin concentration, and total hemoglobin concentration, were observed during hypercapnia. Comparison of blood flow changes measured by VENC MRI in the jugular veins and by DCS revealed a strong linear relationship, R=0.88, p<0.001, slope=0.91±0.07. Similar correlations were observed between DCS and VENC MRI in the superior vena cava, R=0.77, slope=0.99±0.12, p<0.001. The relationship between VENC MRI in the aorta and DCS, a negative control, was weakly correlated, R=0.46, slope=1.77±0.45, p<0.001.
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Affiliation(s)
- Erin M Buckley
- University of Pennsylvania, Department of Physics and Astronomy, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, USA.
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123
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Abstract
Little is known about cerebral blood flow, cerebral blood volume (CBV), oxygenation, and oxygen consumption in the premature newborn brain. We combined quantitative frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation (SO(2)) and CBV with diffusion correlation spectroscopy measures of cerebral blood flow index (BF(ix)) to determine the relationship between these measures, gestational age at birth (GA), and chronological age. We followed 56 neonates of various GA once a week during their hospital stay. We provide absolute values of SO(2) and CBV, relative values of BF(ix), and relative cerebral metabolic rate of oxygen (rCMRO(2)) as a function of postmenstrual age (PMA) and chronological age for four GA groups. SO(2) correlates with chronological age (r=-0.54, P value ≤0.001) but not with PMA (r=-0.07), whereas BF(ix) and rCMRO(2) correlate better with PMA (r=0.37 and 0.43, respectively, P value ≤0.001). Relative CMRO2 during the first month of life is lower when GA is lower. Blood flow index and rCMRO(2) are more accurate biomarkers of the brain development than SO(2) in the premature newborns.
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124
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Lin PY, Roche-Labarbe N, Dehaes M, Fenoglio A, Grant PE, Franceschini MA. Regional and hemispheric asymmetries of cerebral hemodynamic and oxygen metabolism in newborns. ACTA ACUST UNITED AC 2012; 23:339-48. [PMID: 22328446 DOI: 10.1093/cercor/bhs023] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Understanding the evolution of regional and hemispheric asymmetries in the early stages of life is essential to the advancement of developmental neuroscience. By using 2 noninvasive optical methods, frequency-domain near-infrared spectroscopy and diffuse correlation spectroscopy, we measured cerebral hemoglobin oxygenation (SO(2)), blood volume (CBV), an index of cerebral blood flow (CBF(i)), and the metabolic rate of oxygen (CMRO(2i)) in the frontal, temporal, and parietal regions of 70 premature and term newborns. In concordance with results obtained using more invasive imaging modalities, we verified both hemodynamic (CBV, CBF(i), and SO(2)) and metabolic (CMRO(2i)) parameters were greater in the temporal and parietal regions than in the frontal region and that these differences increased with age. In addition, we found that most parameters were significantly greater in the right hemisphere than in the left. Finally, in comparing age-matched males and females, we found that males had higher CBF(i) in most cortical regions, higher CMRO(2i) in the frontal region, and more prominent right-left CBF(i) asymmetry. These results reveal, for the first time, that we can detect regional and hemispheric asymmetries in newborns using noninvasive optical techniques. Such a bedside screening tool may facilitate early detection of abnormalities and delays in maturation of specific cortical areas.
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Affiliation(s)
- Pei-Yi Lin
- The Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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125
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Kang D, Kupinski MA. Effect of noise on modulation amplitude and phase in frequency-domain diffusive imaging. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:016010. [PMID: 22352660 PMCID: PMC4098065 DOI: 10.1117/1.jbo.17.1.016010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 11/13/2011] [Accepted: 11/16/2011] [Indexed: 05/30/2023]
Abstract
We theoretically investigate the effect of noise on frequency-domain heterodyne and/or homodyne measurements of intensity-modulated beams propagating through diffusive media, such as a photon density wave. We assumed that the attenuated amplitude and delayed phase are estimated by taking the Fourier transform of the noisy, modulated output data. We show that the estimated amplitude and phase are biased when the number of output photons is small. We also show that the use of image intensifiers for photon amplification in heterodyne or homodyne measurements increases the amount of biases. Especially, it turns out that the biased estimation is independent of AC-dependent noise in sinusoidal heterodyne or homodyne outputs. Finally, the developed theory indicates that the previously known variance model of modulation amplitude and phase is not valid in low light situations. Monte-Carlo simulations with varied numbers of input photons verify our theoretical trends of the bias.
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Affiliation(s)
- Dongyel Kang
- University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, USA.
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126
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Yu G. Near-infrared diffuse correlation spectroscopy in cancer diagnosis and therapy monitoring. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:010901. [PMID: 22352633 PMCID: PMC3380819 DOI: 10.1117/1.jbo.17.1.010901] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/08/2011] [Accepted: 11/14/2011] [Indexed: 05/19/2023]
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.
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Affiliation(s)
- Guoqiang Yu
- University of Kentucky, Center for Biomedical Engineering, Lexington, Kentucky 40506-0070, USA.
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127
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Xu F, Uh J, Liu P, Lu H. On improving the speed and reliability of T2-relaxation-under-spin-tagging (TRUST) MRI. Magn Reson Med 2011; 68:198-204. [PMID: 22127845 DOI: 10.1002/mrm.23207] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 08/03/2011] [Accepted: 08/15/2011] [Indexed: 11/06/2022]
Abstract
A T(2) -relaxation-under-spin-tagging technique was recently developed to estimate cerebral blood oxygenation, providing potentials for noninvasive assessment of the brain's oxygen consumption. A limitation of the current sequence is the need for long repetition time, as shorter repetition time causes an over-estimation in blood R(2). This study proposes a postsaturation T(2)-relaxation-under-spin-tagging by placing a nonselective 90° pulse after the signal acquisition to reset magnetization in the whole brain. This scheme was found to eliminate estimation bias at a slight cost of precision. To improve the precision, echo time of the sequence was optimized and it was found that a modest echo time shortening of 3.4 ms can reduce the estimation error by 49%. We recommend the use of postsaturation T(2)-relaxation-under-spin-tagging sequence with a repetition time of 3000 ms and a echo time of 3.6 ms, which allows the determination of global venous oxygenation with scan duration of 1 min 12 s and an estimation precision of ± 1% (in units of oxygen saturation percentage).
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Affiliation(s)
- Feng Xu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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128
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Boas DA, Franceschini MA. Haemoglobin oxygen saturation as a biomarker: the problem and a solution. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4407-24. [PMID: 22006898 PMCID: PMC3263786 DOI: 10.1098/rsta.2011.0250] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy measures of haemoglobin oxygen saturation are often used as an indicator of sufficient oxygen delivery to assess injury susceptibility and tissue damage. They have also often been used as a surrogate measure of oxygen metabolism. Unfortunately, these measures have generally failed to provide robust indicators of injury and metabolism. In this paper, we first review when haemoglobin oxygen saturation does work as a robust indicator, and then detail when and why it fails for assessing brain injury and breast cancer. Finally, we discuss the solution to obtain more robust measures of tissue injury and cancer by combining oxygen saturation measurements with measures of blood flow and volume to more accurately estimate oxygen metabolism.
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Affiliation(s)
- David A Boas
- Optics Division of the Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, 149 13th St rm 2301, Charlestown, MA 02129, USA.
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129
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Mesquita RC, Durduran T, Yu G, Buckley EM, Kim MN, Zhou C, Choe R, Sunar U, Yodh AG. Direct measurement of tissue blood flow and metabolism with diffuse optics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4390-406. [PMID: 22006897 PMCID: PMC3263785 DOI: 10.1098/rsta.2011.0232] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Diffuse optics has proven useful for quantitative assessment of tissue oxy- and deoxyhaemoglobin concentrations and, more recently, for measurement of microvascular blood flow. In this paper, we focus on the flow monitoring technique: diffuse correlation spectroscopy (DCS). Representative clinical and pre-clinical studies from our laboratory illustrate the potential of DCS. Validation of DCS blood flow indices in human brain and muscle is presented. Comparison of DCS with arterial spin-labelled MRI, xenon-CT and Doppler ultrasound shows good agreement (0.50<r<0.95) over a wide range of tissue types and source detector distances, corroborating the potential of the method to measure perfusion non-invasively and in vivo at the microvasculature level. All-optical measurements of cerebral oxygen metabolism in both rat brain, following middle cerebral artery occlusion, and human brain, during functional activation, are also described. In both situations, the use of combined DCS and diffuse optical spectroscopy/near-infrared spectroscopy to monitor changes in oxygen consumption by the tissue is demonstrated. Finally, recent results spanning from gene expression-induced angiogenic response to stroke care and cancer treatment monitoring are discussed. Collectively, the research illustrates the capability of DCS to quantitatively monitor perfusion from bench to bedside, providing results that match up both with literature findings and with similar experiments performed with other techniques.
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Affiliation(s)
- Rickson C Mesquita
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.
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130
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Wojtkiewicz S, Liebert A, Rix H, Maniewski R. Evaluation of algorithms for microperfusion assessment by fast simulations of laser Doppler power spectral density. Phys Med Biol 2011; 56:7709-23. [PMID: 22085805 DOI: 10.1088/0031-9155/56/24/002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In classical laser Doppler (LD) perfusion measurements, zeroth- and first-order moments of the power spectral density of the LD signal are utilized for the calculation of a signal corresponding to the concentration, speed and flow of red blood cells (RBCs). We have analysed the nonlinearities of the moments in relation to RBC speed distributions, parameters of filters utilized in LD instruments and the signal-to-noise ratio. We have developed a new method for fast simulation of the spectrum of the LD signal. The method is based on a superposition of analytically calculated Doppler shift probability distributions derived for the assumed light scattering phase function. We have validated the method by a comparison of the analytically calculated spectra with results of Monte Carlo (MC) simulations. For the semi-infinite, homogeneous medium and the single Doppler scattering regime, the analytical calculation describes LD spectra with the same accuracy as the MC simulation. The method allows for simulating the LD signal in time domain and furthermore analysing the index of perfusion for the assumed wavelength of the light, optical properties of the tissue and concentration of RBCs. Fast simulations of the LD signal in time domain and its frequency spectrum can be utilized in applications where knowledge of the LD photocurrent is required, e.g. in the development of detectors for tissue microperfusion monitoring or in measurements of the LD autocorrelation function for perfusion measurements. The presented fast method for LD spectra calculation can be used as a tool for evaluation of signal processing algorithms used in the LD method and/or for the development of new algorithms of the LD flowmetry and imaging. We analysed LD spectra obtained by analytical calculations using a classical algorithm applied in classical LD perfusion measurements. We observed nonlinearity of the first moment M₁ for low and high speeds of particles (v < 2 mm s⁻¹, v > 10 mm s⁻¹). It was also noted that the first moment M(1) is less sensitive to the change of the mean RBC speed for flat speed distributions. The low-pass filter frequency f₂ implemented in the LD instrument has a significant influence on the first moment of the spectrum. In particular, for a cut-off frequency lower than 10 kHz the M₁ value is strongly underestimated.
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Affiliation(s)
- S Wojtkiewicz
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland.
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131
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Irwin D, Dong L, Shang Y, Cheng R, Kudrimoti M, Stevens SD, Yu G. Influences of tissue absorption and scattering on diffuse correlation spectroscopy blood flow measurements. BIOMEDICAL OPTICS EXPRESS 2011; 2:1969-85. [PMID: 21750773 PMCID: PMC3130582 DOI: 10.1364/boe.2.001969] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/13/2011] [Accepted: 06/14/2011] [Indexed: 05/19/2023]
Abstract
In this study we evaluate the influences of optical property assumptions on near-infrared diffuse correlation spectroscopy (DCS) flow index measurements. The optical properties, absorption coefficient (µ(a)) and reduced scattering coefficient (µ(s)'), are independently varied using liquid phantoms and measured concurrently with the flow index using a hybrid optical system combining a dual-wavelength DCS flow device with a commercial frequency-domain tissue-oximeter. DCS flow indices are calculated at two wavelengths (785 and 830 nm) using measured µ(a) and µ(s)' or assumed constant µ(a) and µ(s)'. Inaccurate µ(s)' assumptions resulted in much greater flow index errors than inaccurate µ(a). Underestimated/overestimated µ(s)' from -35%/+175% lead to flow index errors of +110%/-80%, whereas underestimated/overestimated µ(a) from -40%/+150% lead to -20%/+40%, regardless of the wavelengths used. Examination of a clinical study involving human head and neck tumors indicates up to +280% flow index errors resulted from inter-patient optical property variations. These findings suggest that studies involving significant µ(a) and µ(s)' changes should concurrently measure flow index and optical properties for accurate extraction of blood flow information.
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Affiliation(s)
- Daniel Irwin
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Lixin Dong
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Yu Shang
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Ran Cheng
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Mahesh Kudrimoti
- Department of Radiation Medicine, University of Kentucky Chandler Hospital, Lexington, KY 40536, USA
| | - Scott D. Stevens
- Department of Radiology, University of Kentucky Chandler Hospital, Lexington, KY 40536, USA
| | - Guoqiang Yu
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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132
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Diop M, Verdecchia K, Lee TY, St Lawrence K. Calibration of diffuse correlation spectroscopy with a time-resolved near-infrared technique to yield absolute cerebral blood flow measurements. BIOMEDICAL OPTICS EXPRESS 2011; 2:2068-81. [PMID: 21750781 PMCID: PMC3130590 DOI: 10.1364/boe.2.002068] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 06/23/2011] [Accepted: 06/25/2011] [Indexed: 05/18/2023]
Abstract
A primary focus of neurointensive care is the prevention of secondary brain injury, mainly caused by ischemia. A noninvasive bedside technique for continuous monitoring of cerebral blood flow (CBF) could improve patient management by detecting ischemia before brain injury occurs. A promising technique for this purpose is diffuse correlation spectroscopy (DCS) since it can continuously monitor relative perfusion changes in deep tissue. In this study, DCS was combined with a time-resolved near-infrared technique (TR-NIR) that can directly measure CBF using indocyanine green as a flow tracer. With this combination, the TR-NIR technique can be used to convert DCS data into absolute CBF measurements. The agreement between the two techniques was assessed by concurrent measurements of CBF changes in piglets. A strong correlation between CBF changes measured by TR-NIR and changes in the scaled diffusion coefficient measured by DCS was observed (R(2) = 0.93) with a slope of 1.05 ± 0.06 and an intercept of 6.4 ± 4.3% (mean ± standard error).
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Affiliation(s)
- Mamadou Diop
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Kyle Verdecchia
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Ting-Yim Lee
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6G 2V4, Canada
| | - Keith St Lawrence
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
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133
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Carp SA, Roche-Labarbe N, Franceschini MA, Srinivasan VJ, Sakadžić S, Boas DA. Due to intravascular multiple sequential scattering, Diffuse Correlation Spectroscopy of tissue primarily measures relative red blood cell motion within vessels. BIOMEDICAL OPTICS EXPRESS 2011; 2:2047-54. [PMID: 21750779 PMCID: PMC3130588 DOI: 10.1364/boe.2.002047] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/13/2011] [Accepted: 06/17/2011] [Indexed: 05/19/2023]
Abstract
We suggest that Diffuse Correlation Spectroscopy (DCS) measurements of tissue blood flow primarily probe relative red blood cell (RBC) motion, due to the occurrence of multiple sequential scattering events within blood vessels. The magnitude of RBC shear-induced diffusion is known to correlate with flow velocity, explaining previous reports of linear scaling of the DCS "blood flow index" with tissue perfusion despite the observed diffusion-like auto-correlation decay. Further, by modeling RBC mean square displacement using a formulation that captures the transition from ballistic to diffusive motion, we improve the fit to experimental data and recover effective diffusion coefficients and velocity de-correlation time scales in the range expected from previous blood rheology studies.
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134
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Shang Y, Cheng R, Dong L, Ryan SJ, Saha SP, Yu G. Cerebral monitoring during carotid endarterectomy using near-infrared diffuse optical spectroscopies and electroencephalogram. Phys Med Biol 2011; 56:3015-32. [PMID: 21508444 DOI: 10.1088/0031-9155/56/10/008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Intraoperative monitoring of cerebral hemodynamics during carotid endarterectomy (CEA) provides essential information for detecting cerebral hypoperfusion induced by temporary internal carotid artery (ICA) clamping and post-CEA hyperperfusion syndrome. This study tests the feasibility and sensitivity of a novel dual-wavelength near-infrared diffuse correlation spectroscopy technique in detecting cerebral blood flow (CBF) and cerebral oxygenation in patients undergoing CEA. Two fiber-optic probes were taped on both sides of the forehead for cerebral hemodynamic measurements, and the instantaneous decreases in CBF and electroencephalogram (EEG) alpha-band power during ICA clamping were compared to test the measurement sensitivities of the two techniques. The ICA clamps resulted in significant CBF decreases (-24.7 ± 7.3%) accompanied with cerebral deoxygenation at the surgical sides (n = 12). The post-CEA CBF were significantly higher (+43.2 ± 16.9%) than the pre-CEA CBF. The CBF responses to ICA clamping were significantly faster, larger and more sensitive than EEG responses. Simultaneous monitoring of CBF, cerebral oxygenation and EEG power provides a comprehensive evaluation of cerebral physiological status, thus showing potential for the adoption of acute interventions (e.g., shunting, medications) during CEA to reduce the risks of severe cerebral ischemia and cerebral hyperperfusion syndrome.
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Affiliation(s)
- Yu Shang
- Center for Biomedical Engineering, University of Kentucky, KY, USA
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135
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Ninck M, Untenberger M, Gisler T. Diffusing-wave spectroscopy with dynamic contrast variation: disentangling the effects of blood flow and extravascular tissue shearing on signals from deep tissue. BIOMEDICAL OPTICS EXPRESS 2010; 1:1502-1513. [PMID: 21258565 PMCID: PMC3018123 DOI: 10.1364/boe.1.001502] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/12/2010] [Accepted: 11/20/2010] [Indexed: 05/19/2023]
Abstract
We investigate the effects of blood flow and extravascular tissue shearing on diffusing-wave spectroscopy (DWS) signals from deep tissue, using an ex vivo porcine kidney model perfused artificially at controlled arterial pressure and flow. Temporal autocorrelation functions g((1))(τ) of the multiply scattered light field show a decay which is described by diffusion for constant flow, with a diffusion coefficient scaling linearly with volume flow rate. Replacing blood by a non-scattering fluid reveals a flow-independent background dynamics of the extravascular tissue. For a sinusoidally driven perfusion, field autocorrelation functions g((1))(τ, t') depend on the phase t' within the pulsation cycle and are approximately described by diffusion. The effective diffusion coefficient D(eff)(t') is modulated at the driving frequency in the presence of blood, showing coupling with flow rate; in the absence of blood, D(eff)(t') is modulated at twice the driving frequency, indicating shearing of extravascular tissue as the origin of the DWS signal. For both constant and pulsatile flow the contribution of extravascular tissue shearing to the DWS signal is small.
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Affiliation(s)
- Markus Ninck
- Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany
| | | | - Thomas Gisler
- Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany
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136
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Zirak P, Delgado-Mederos R, Martí-Fàbregas J, Durduran T. Effects of acetazolamide on the micro- and macro-vascular cerebral hemodynamics: a diffuse optical and transcranial doppler ultrasound study. BIOMEDICAL OPTICS EXPRESS 2010; 1:1443-1459. [PMID: 21258561 PMCID: PMC3018112 DOI: 10.1364/boe.1.001443] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/07/2010] [Accepted: 11/07/2010] [Indexed: 05/24/2023]
Abstract
Acetazolamide (ACZ) was used to stimulate the cerebral vasculature on ten healthy volunteers to assess the cerebral vasomotor reactivity (CVR). We have combined near infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS) and transcranial Doppler (TCD) technologies to non-invasively assess CVR in real-time by measuring oxy- and deoxy-hemoglobin concentrations, using NIRS, local cerebral blood flow (CBF), using DCS, and blood flow velocity (CBFV) in the middle cerebral artery, using TCD. Robust and persistent increases in oxy-hemoglobin concentration, CBF and CBFV were observed. A significant agreement was found between macro-vascular (TCD) and micro-vascular (DCS) hemodynamics, between the NIRS and TCD data, and also within NIRS and DCS results. The relative cerebral metabolic rate of oxygen, rCMRO(2), was also determined, and no significant change was observed. Our results showed that the combined diffuse optics-ultrasound technique is viable to follow (CVR) and rCMRO(2) changes in adults, continuously, at the bed-side and in real time.
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Affiliation(s)
- Peyman Zirak
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology
Park, 08860 Castelldefels, Barcelona, Spain
| | | | - Joan Martí-Fàbregas
- Department of Neurology, Hospital de la Santa Creu i Sant Pau,
Barcelona, Spain
| | - Turgut Durduran
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology
Park, 08860 Castelldefels, Barcelona, Spain
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137
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Petschke A, La Rivière PJ. Comparison of intensity-modulated continuous-wave lasers with a chirped modulation frequency to pulsed lasers for photoacoustic imaging applications. BIOMEDICAL OPTICS EXPRESS 2010; 1:1188-1195. [PMID: 21258540 PMCID: PMC3018082 DOI: 10.1364/boe.1.001188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/16/2010] [Accepted: 10/15/2010] [Indexed: 05/14/2023]
Abstract
Using a Green's function solution to the photoacoustic wave equation, we compare intensity-modulated continuous-wave (CW) lasers with a chirped modulation frequency to pulsed lasers for photoacoustic imaging applications. Assuming the same transducer is used in both cases, we show that the axial resolution is identical and is determined by the transducer and material properties of the object. We derive a simple formula relating the signal-to-noise ratios (SNRs) of the two imaging systems that only depends on the fluence of each pulse and the time-bandwidth product of the chirp pulse. We also compare the SNR of the two systems assuming the fluence is limited by the American National Standards Institute (ANSI) laser safety guidelines for skin. We find that the SNR is about 20 dB to 30 dB larger for pulsed laser systems for reasonable values of the parameters. However, CW diode lasers have the advantage of being compact and relatively inexpensive, which may outweigh the lower SNR in many applications.
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Affiliation(s)
- Adam Petschke
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Patrick J. La Rivière
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
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138
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Mesquita RC, Skuli N, Kim MN, Liang J, Schenkel S, Majmundar AJ, Simon MC, Yodh AG. Hemodynamic and metabolic diffuse optical monitoring in a mouse model of hindlimb ischemia. BIOMEDICAL OPTICS EXPRESS 2010; 1:1173-1187. [PMID: 21258539 PMCID: PMC3018079 DOI: 10.1364/boe.1.001173] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/29/2010] [Accepted: 10/12/2010] [Indexed: 05/06/2023]
Abstract
Murine hindlimb ischemia is a useful model for investigation of the mechanisms of peripheral arterial disease and for understanding the role of endothelial cells and generic factors affecting vascular regeneration or angiogenesis. To date, important research with these models has explored tissue reperfusion following ischemia with Laser Doppler methods, methods which provide information about superficial (~mm) vascular regeneration. In this work, we employ diffuse correlation spectroscopy (DCS) and diffuse optical spectroscopy (DOS) in mice after hindlimb ischemia. We hypothesize that vascular re-growth is not uniform in tissue, and therefore, since diffuse optical methods are capable of probing deep tissues, that the diffuse optics approach will provide a more complete picture of the angiogenesis process throughout the whole depth profile of the limb. Besides increased depth penetration, the combined measurements of DCS and DOS enable all-optical, noninvasive, longitudinal monitoring of tissue perfusion and oxygenation that reveals the interplay between these hemodynamic parameters during angiogenesis. Control mice were found to reestablish 90% of perfusion and oxygen consumption during this period, but oxygen saturation in the limb only partially recovered to about 30% of its initial value. The vascular recovery of mice with endothelial cell-specific deletion of HIF-2α was found to be significantly impaired relative to control mice, indicating that HIF-2α is important for endothelial cell functions in angiogenesis. Comparison of DOS/DCS measurements to parallel measurements in the murine models using Laser Doppler Flowmetry reveal differences in the reperfusion achieved by superficial versus deep tissue during neoangiogenesis; findings from histological analysis of blood vessel development were further correlated with these differences. In general, the combination of DCS and DOS enables experimenters to obtain useful information about oxygenation, metabolism, and perfusion throughout the limb. The results establish diffuse optics as a practical noninvasive method to evaluate the role of transcription factors, such as the endothelial cell-specific HIF-2α, in genetic ally modified mice.
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Affiliation(s)
- Rickson C. Mesquita
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicolas Skuli
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Meeri N. Kim
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jiaming Liang
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
- School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Steve Schenkel
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amar J. Majmundar
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M. Celeste Simon
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arjun G. Yodh
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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139
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Carp SA, Dai GP, Boas DA, Franceschini MA, Kim YR. Validation of diffuse correlation spectroscopy measurements of rodent cerebral blood flow with simultaneous arterial spin labeling MRI; towards MRI-optical continuous cerebral metabolic monitoring. BIOMEDICAL OPTICS EXPRESS 2010; 1:553-565. [PMID: 21258489 PMCID: PMC3017992 DOI: 10.1364/boe.1.000553] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 07/13/2010] [Accepted: 07/13/2010] [Indexed: 05/18/2023]
Abstract
Cerebral blood flow (CBF) during stepped hypercapnia was measured simultaneously in the rat brain using near-infrared diffuse correlation spectroscopy (DCS) and arterial spin labeling MRI (ASL). DCS and ASL CBF values agree very well, with high correlation (R=0.86, p< 10(-9)), even when physiological instability perturbed the vascular response. A partial volume effect was evident in the smaller magnitude of the optical CBF response compared to the MRI values (averaged over the cortical area), primarily due to the inclusion of white matter in the optically sampled volume. The 8.2 and 11.7 mm mid-separation channels of the multi-distance optical probe had the lowest partial volume impact, reflecting ~75 % of the MR signal change. Using a multiplicative correction factor, the ASL CBF could be predicted with no more than 10% relative error, affording an opportunity for real-time relative cerebral metabolism monitoring in conjunction with MR measurement of cerebral blood volume using super paramagnetic contrast agents.
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Affiliation(s)
- S. A. Carp
- Athinoula A. Martinos Center for Biomedical Imaging,
Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129,
USA
| | - G. P. Dai
- Athinoula A. Martinos Center for Biomedical Imaging,
Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129,
USA
| | - D. A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging,
Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129,
USA
| | - M. A. Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging,
Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129,
USA
| | - Y. R. Kim
- Athinoula A. Martinos Center for Biomedical Imaging,
Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129,
USA
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140
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Durduran T, Choe R, Baker WB, Yodh AG. Diffuse Optics for Tissue Monitoring and Tomography. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2010; 73:076701. [PMID: 26120204 PMCID: PMC4482362 DOI: 10.1088/0034-4885/73/7/076701] [Citation(s) in RCA: 571] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This review describes the diffusion model for light transport in tissues and the medical applications of diffuse light. Diffuse optics is particularly useful for measurement of tissue hemodynamics, wherein quantitative assessment of oxy- and deoxy-hemoglobin concentrations and blood flow are desired. The theoretical basis for near-infrared or diffuse optical spectroscopy (NIRS or DOS, respectively) is developed, and the basic elements of diffuse optical tomography (DOT) are outlined. We also discuss diffuse correlation spectroscopy (DCS), a technique whereby temporal correlation functions of diffusing light are transported through tissue and are used to measure blood flow. Essential instrumentation is described, and representative brain and breast functional imaging and monitoring results illustrate the workings of these new tissue diagnostics.
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Affiliation(s)
- T Durduran
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
| | - R Choe
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - W B Baker
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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