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Robinson MB, Renna M, Ozana N, Martin AN, Otic N, Carp SA, Franceschini MA. Portable, high speed blood flow measurements enabled by long wavelength, interferometric diffuse correlation spectroscopy (LW-iDCS). Sci Rep 2023; 13:8803. [PMID: 37258644 PMCID: PMC10232495 DOI: 10.1038/s41598-023-36074-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/29/2023] [Indexed: 06/02/2023] Open
Abstract
Diffuse correlation spectroscopy (DCS) is an optical technique that can be used to characterize blood flow in tissue. The measurement of cerebral hemodynamics has arisen as a promising use case for DCS, though traditional implementations of DCS exhibit suboptimal signal-to-noise ratio (SNR) and cerebral sensitivity to make robust measurements of cerebral blood flow in adults. In this work, we present long wavelength, interferometric DCS (LW-iDCS), which combines the use of a longer illumination wavelength (1064 nm), multi-speckle, and interferometric detection, to improve both cerebral sensitivity and SNR. Through direct comparison with long wavelength DCS based on superconducting nanowire single photon detectors, we demonstrate an approximate 5× improvement in SNR over a single channel of LW-DCS in the measured blood flow signals in human subjects. We show equivalence of extracted blood flow between LW-DCS and LW-iDCS, and demonstrate the feasibility of LW-iDCS measured at 100 Hz at a source-detector separation of 3.5 cm. This improvement in performance has the potential to enable robust measurement of cerebral hemodynamics and unlock novel use cases for diffuse correlation spectroscopy.
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Affiliation(s)
- Mitchell B Robinson
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
| | - Marco Renna
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Nisan Ozana
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Bar-Ilan University, Tel Aviv District, Ramat Gan, Israel
| | - Alyssa N Martin
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Nikola Otic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Stefan A Carp
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Maria Angela Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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2
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Levi AR, Hazan Y, Lev A, Sfez BG, Rosenthal A. Homodyne time-of-flight acousto-optic imaging for low-gain photodetector. Biomed Eng Lett 2023; 13:49-56. [PMID: 36711164 PMCID: PMC9873866 DOI: 10.1007/s13534-022-00252-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 10/27/2022] [Accepted: 11/14/2022] [Indexed: 11/20/2022] Open
Abstract
Acousto-optics imaging (AOI) is a hybrid imaging modality that is capable of mapping the light fluence rate in deep tissue by local ultrasound modulation of the diffused photons. Since the intensity of the modulated photons is relatively low, AOI systems often rely on high-gain photodetectors, e.g. photomultiplier tubes (PMTs), which limit scalability due to size and cost and may significantly increase the relative shot-noise in the detected signal due to low quantum yields or gain noise. In this work, we have developed a homodyne AOI scheme in which the modulated photons are amplified by interference with a reference beam, enabling their detection with a single low-gain photodetector in reflection-mode configuration. We experimentally demonstrate our approach with a silicon photodiode, achieving over a 4-fold improvement in SNR in comparison to a PMT-based setup. The increased SNR manifested in lower background noise level thus enabling deeper imaging depths. The use of a fiber-based configuration enables the integration of our scheme in a hand-held AOI probe.
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Affiliation(s)
- Ahiad R. Levi
- Andrew and Erna Viterbi Faculty of Electrical & Computer Engineering, Technion – Israel Institute of Technology, 32000 Technion City, Haifa, Israel
| | - Yoav Hazan
- Andrew and Erna Viterbi Faculty of Electrical & Computer Engineering, Technion – Israel Institute of Technology, 32000 Technion City, Haifa, Israel
| | - Aner Lev
- The Israel Center for Advanced Photonics (ICAP), Soreq NRC, Yavne, Israel
| | - Bruno G. Sfez
- The Israel Center for Advanced Photonics (ICAP), Soreq NRC, Yavne, Israel
| | - Amir Rosenthal
- Andrew and Erna Viterbi Faculty of Electrical & Computer Engineering, Technion – Israel Institute of Technology, 32000 Technion City, Haifa, Israel
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Robinson MB, Renna M, Ozana NN, Peruch A, Sakadzic S, Blackwell ML, Richardson JM, Aull BF, Carp SA, Franceschini MA. Diffuse Correlation Spectroscopy Beyond the Water Peak Enabled by Cross-Correlation of the Signals From InGaAs/InP Single Photon Detectors. IEEE Trans Biomed Eng 2022; 69:1943-1953. [PMID: 34847015 PMCID: PMC9119938 DOI: 10.1109/tbme.2021.3131353] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Diffuse correlation spectroscopy (DCS) is an optical technique that allows for the non-invasive measurement of blood flow. Recent work has shown that utilizing longer wavelengths beyond the traditional NIR range provides a significant improvement to signal-to-noise ratio (SNR). However, current detectors both sensitive to longer wavelengths and suitable for clinical applications (InGaAs/InP SPADs) suffer from suboptimal afterpulsing and dark noise characteristics. To overcome these barriers, we introduce a cross correlation method to more accurately recover blood flow information using InGaAs/InP SPADs. METHODS Two InGaAs/InP SPAD detectors were used for during in vitro and in vivo DCS measurements. Cross correlation of the photon streams from each detector was performed to calculate the correlation function. Detector operating parameters were varied to determine parameters which maximized measurement SNR.State-space modeling was performed to determine the detector characteristics at each operating point. RESULTS Evaluation of detector characteristics was performed across the range of operating conditions. Modeling the effects of the detector noise on the correlation function provided a method to correct the distortion of the correlation curve, yielding accurate recovery of flow information as confirmed by a reference detector. CONCLUSION Through a combination of cross-correlation of the signals from two detectors, model-based characterization of detector response, and optimization of detector operating parameters, the method allows for the accurate estimation of the true blood flow index. SIGNIFICANCE This work presents a method by which DCS can be performed at longer NIR wavelengths with existing detector technology, taking advantage of the increased SNR.
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Badenes R, Bogossian EG, Chisbert V, Robba C, Oddo M, Taccone FS, Matta BF. The role of non-invasive brain oximetry in adult critically ill patients without primary brain injury. Minerva Anestesiol 2021; 87:1226-1238. [PMID: 33938677 DOI: 10.23736/s0375-9393.21.15333-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A primary objective in intensive care and perioperative settings is to promote an adequate supply and delivery of oxygen to tissues and organs, particularly to the brain. Cerebral near infrared spectroscopy (NIRS) is a non-invasive, continuous monitoring technique, that can be used to assess cerebral oxygenation. Using NIRS to monitor cerebral oximetry is not new, and has been in widespread use in neonates and cardiac surgery for decades. In addition, it has become common to see NIRS being used in adult and pediatric cardiac surgery, acute neurological diseases, neurosurgical procedures, vascular surgery, severe trauma and other acute medical diseases. Furthermore, recent evidence suggests a role for NIRS in the perioperative settings; detecting and preventing episodes of cerebral desaturation aiming to reduce the development of post-operative delirium. NIRS is not without its limitations; these include the risk of extra-cranial contamination, spatial limitations and skin blood flow/volume changes, as well being a measure of localized blood oxygenation underneath the sensor. However, NIRS is a non-invasive technique and can, therefore, be used in those patients without indications or justification for invasive brain monitoring; non-neurosurgical procedures such as liver transplantation, major orthopedic surgery and critically illness where the brain is at risk. The aim of this manuscript was to discuss the physical principles of NIRS and to report the current evidence regarding its use in critically ill patients without primary non-anoxic brain injury.
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Affiliation(s)
- Rafael Badenes
- Department of Anesthesiology and Surgical-Trauma Intensive Care, Hospital Clinic Universitari de Valencia, University of Valencia, Valencia, Spain - .,Department of Surgery, School of Medicine, University of Valencia, Valencia, Spain - .,INCLIVA Health Research Institute, Valencia, Spain -
| | - Elisa G Bogossian
- Department of Intensive Care Medicine, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Vicente Chisbert
- INCLIVA Health Research Institute, Valencia, Spain.,Escuela de Doctorado, Universidad Católica de Valencia, Valencia, Spain
| | - Chiara Robba
- Anaesthesia and Intensive Care, IRCSS S. Martino Hospital, Genoa, Italy
| | - Mauro Oddo
- Department of Intensive Care Medicine, Faculty of Biology and Medicine, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne University Hospital, Lausanne, Switzerland
| | - Fabio S Taccone
- Department of Intensive Care Medicine, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Basil F Matta
- Trauma and NeuroCritical Care Unit, Cambridge University Hospital, Cambridge, UK
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Zhou W, Kholiqov O, Zhu J, Zhao M, Zimmermann LL, Martin RM, Lyeth BG, Srinivasan VJ. Functional interferometric diffusing wave spectroscopy of the human brain. SCIENCE ADVANCES 2021; 7:eabe0150. [PMID: 33980479 PMCID: PMC8115931 DOI: 10.1126/sciadv.abe0150] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 03/23/2021] [Indexed: 05/18/2023]
Abstract
Cerebral blood flow (CBF) is essential for brain function, and CBF-related signals can inform us about brain activity. Yet currently, high-end medical instrumentation is needed to perform a CBF measurement in adult humans. Here, we describe functional interferometric diffusing wave spectroscopy (fiDWS), which introduces and collects near-infrared light via the scalp, using inexpensive detector arrays to rapidly monitor coherent light fluctuations that encode brain blood flow index (BFI), a surrogate for CBF. Compared to other functional optical approaches, fiDWS measures BFI faster and deeper while also providing continuous wave absorption signals. Achieving clear pulsatile BFI waveforms at source-collector separations of 3.5 cm, we confirm that optical BFI, not absorption, shows a graded hypercapnic response consistent with human cerebrovascular physiology, and that BFI has a better contrast-to-noise ratio than absorption during brain activation. By providing high-throughput measurements of optical BFI at low cost, fiDWS will expand access to CBF.
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Affiliation(s)
- Wenjun Zhou
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, USA
| | - Oybek Kholiqov
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, USA
| | - Jun Zhu
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, USA
| | - Mingjun Zhao
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, USA
| | - Lara L Zimmermann
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, USA
| | - Ryan M Martin
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, USA
| | - Bruce G Lyeth
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, USA
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, USA.
- Department of Ophthalmology and Vision Science, University of California, Davis, Sacramento, CA, USA
- Department of Ophthalmology, NYU Langone Health, New York, NY, USA
- Department of Radiology, NYU Langone Health, New York, NY, USA
- Tech4Health Institute, NYU Langone Health, New York, NY, USA
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Robinson MB, Carp SA, Peruch A, Boas DA, Franceschini MA, Sakadžić S. Characterization of continuous wave ultrasound for acousto-optic modulated diffuse correlation spectroscopy (AOM-DCS). BIOMEDICAL OPTICS EXPRESS 2020; 11:3071-3090. [PMID: 32637242 PMCID: PMC7316011 DOI: 10.1364/boe.390322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/03/2020] [Accepted: 04/25/2020] [Indexed: 05/25/2023]
Abstract
Intra and post-operative blood flow monitoring of tissue has been shown to be effective in the improvement of patient outcomes. Diffuse correlation spectroscopy (DCS) has been shown to be effective in measuring blood flow at the bedside, and is a useful technique in measuring cerebral blood flow (CBF) in many clinical settings. However, DCS suffers from reduced sensitivity to blood flow changes at larger tissue depths, making measurements of CBF in adults difficult. This issue can be addressed with acousto-optic modulated diffuse correlation spectroscopy (AOM-DCS), which is a hybrid technique that combines the sensitivity of DCS to blood flow with ultrasound resolution to allow for improved spatial resolution of the optical signal based on knowledge of the area which is insonified by ultrasound. We present a quantitative model for perfusion estimation based on AOM-DCS in the presence of continuous wave ultrasound, supported by theoretical derivations, Monte Carlo simulations, and phantom and human subject experiments. Quantification of the influence of individual mechanisms that contribute to the temporal fluctuations of the optical intensity due to ultrasound is shown to agree with previously derived results. By using this model, the recovery of blood-flow induced scatterer dynamics based on ultrasound-modulated light is shown to deviate by less than one percent from the standard DCS measurement of scatterer dynamics over a range of optical scattering values and scatterer motion conditions. This work provides an important step towards future implementation of AOM-DCS setups with more complex spatio-temporal distributions of ultrasound pressure, which are needed to enhance the DCS spatial resolution.
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Affiliation(s)
- Mitchell B. Robinson
- Optics at Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
- Harvard-MIT Program in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stefan A. Carp
- Optics at Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Adriano Peruch
- Optics at Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - David A. Boas
- Boston University, Boston University Neurophotonics Center, Boston, MA 02215, USA
| | - Maria Angela Franceschini
- Optics at Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Sava Sakadžić
- Optics at Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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7
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Francoeur CL, Lee J, Dangayach N, Gidwani U, Mayer SA. Non-invasive cerebral perfusion monitoring in cardiac arrest patients: a prospective cohort study. Clin Neurol Neurosurg 2020; 196:105970. [PMID: 32505869 DOI: 10.1016/j.clineuro.2020.105970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To determine if non-invasive cerebral perfusion estimation provided by a new acousto-optic technology can be used as a reliable predictor of neurological outcome. PATIENTS AND METHODS We performed a prospective, observational cohort study of consecutive comatose patients successfully resuscitated from out-of-hospital cardiac arrest. Patients were monitored using c-FLOW (Ornim Medical) from critical care unit admission up to 72 h, full awakening, or death. Primary outcome was favourable neurological outcome at hospital discharge, defined as a Cerebral Performance Category score of 1 or 2. RESULTS A total of 21 patients were enrolled, without any loss to follow-up. Mean perfusion index over the monitoring period was not associated with functional outcome at hospital discharge (OR 1.03 [0.93, 1.17]). Adjustment for initial rhythm, time to return of spontaneous circulation and Glasgow coma scale motor score did not significantly alter the results (OR 1.06 [0.99, 1.12]). Mean perfusion index showed a poor discriminative value with an area under the curve of 0.60 for functional outcome (0.64 for survival). Correlation between the probes was weak (Pearson coefficient 0.35). CONCLUSION Cerebral perfusion monitoring using a c-FLOW device in survivors of cardiac arrest is feasible, but reliability of the information provided has yet to be demonstrated. In our cohort, we were unable to identify any association between the perfusion index and clinical outcomes at discharge. As such, clinical management of cardiac arrest patients based on non-invasive perfusion index is not supported and should be limited to research protocols. The trial was registered with ClinicalTrials.gov, number NCT02575196.
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Affiliation(s)
- Charles L Francoeur
- CHU de Québec-Université Laval Research Centre, Population Health and Optimal Health Practises Research Unit (Trauma-Emergency-Critical Care Medicine), Université Laval, 1401, 18e rue, Québec City, Québec, Canada; Division of Critical Care Medicine, Department of Anesthesiology and Critical Care Medicine, Université Laval, Québec City, Québec, Canada.
| | - James Lee
- Division of Neurocritical Care, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104, United States
| | - Neha Dangayach
- Departments of Neurology and Neurosurgery, Mount Sinai Hospital, 1468 Madison Ave, New York, NY 10029, United States
| | - Umesh Gidwani
- Cardiology, Pulmonary, Critical Care and Sleep Medicine, Mount Sinai Hospital, 1468 Madison Ave, New York, NY 10029, United States; Cardiac Critical Care Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, 1468 Madison Ave, New York, NY 10029, United States; Cardiac ICU & Cardiac Stepdown Unit, Mount Sinai Hospital, 1468 Madison Ave, New York, NY 10029, United States
| | - Stephan A Mayer
- Department of Neurology, Henry Ford Health System, 2799 W. Grand Blvd, Clara Ford Pavillion, Room 462, Detroit, MI 48202, United States; Neurology, Wayne State University School of Medicine, Detroit, Michigan, United States
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8
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Levi A, Monin S, Hahamovich E, Lev A, Sfez BG, Rosenthal A. Increased SNR in acousto-optic imaging via coded ultrasound transmission. OPTICS LETTERS 2020; 45:2858-2861. [PMID: 32412486 DOI: 10.1364/ol.392617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
Acousto-optic imaging (AOI) is a non-invasive method that uses acoustic modulation to map the light fluence inside biological tissue. In many AOI implementations, ultrasound pulses are used in a time-gated measurement to perform depth-resolved imaging without the need for mechanical scanning. However, to achieve high axial resolution, it is required that ultrasound pulses with few cycles are used, limiting the modulation strength. In this Letter, we develop a new approach to pulse-based AOI in which coded ultrasound transmission is used. In coded-transmission AOI (CT-AOI), one may achieve an axial resolution that corresponds to a single cycle, but with a signal-to-noise ratio (SNR) that scales as the square root of the number of cycles. Using CT-AOI with 79 cycles, we experimentally demonstrate over four-fold increase in SNR in comparison to a single-cycle AOI scheme.
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9
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Caccioppola A, Carbonara M, Macrì M, Longhi L, Magnoni S, Ortolano F, Triulzi F, Zanier ER, Zoerle T, Stocchetti N. Ultrasound-tagged near-infrared spectroscopy does not disclose absent cerebral circulation in brain-dead adults. Br J Anaesth 2018; 121:588-594. [PMID: 30115257 DOI: 10.1016/j.bja.2018.04.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 04/09/2018] [Accepted: 05/04/2018] [Indexed: 10/14/2022] Open
Abstract
BACKGROUND Near-infrared spectroscopy, a non-invasive technique for monitoring cerebral oxygenation, is widely used, but its accuracy is questioned because of the possibility of extra-cranial contamination. Ultrasound-tagged near-infrared spectroscopy (UT-NIRS) has been proposed as an improvement over previous methods. We investigated UT-NIRS in healthy volunteers and in brain-dead patients. METHODS We studied 20 healthy volunteers and 20 brain-dead patients with two UT-NIRS devices, CerOx™ and c-FLOW™ (Ornim Medical, Kfar Saba, Israel), which measure cerebral flow index (CFI), a parameter related to changes in cerebral blood flow (CBF). Monitoring started after the patients had been declared brain dead for a median of 34 (range: 11-300) min. In 11 cases, we obtained further demonstration of absent CBF. RESULTS In healthy volunteers, CFI was markedly different in the two hemispheres in the same subject, with wide variability amongst subjects. In brain-dead patients (median age: 64 yr old, 45% female; 20% traumatic brain injury, 40% subarachnoid haemorrhage, and 40% intracranial haemorrhage), the median (inter-quartile range) CFI was 41 (36-47), significantly higher than in volunteers (33; 27-36). CONCLUSIONS In brain-dead patients, where CBF is absent, the UT-NIRS findings can indicate an apparently perfused brain. This might reflect an insufficient separation of signals from extra-cranial structures from a genuine appraisal of cerebral perfusion. For non-invasive assessment of CBF-related parameters, the near-infrared spectroscopy still needs substantial improvement.
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Affiliation(s)
- A Caccioppola
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - M Carbonara
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - M Macrì
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - L Longhi
- Neurosurgical Intensive Care Unit, Department of Anesthesia and Critical Care Medicine, Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII, Bergamo, Italy
| | - S Magnoni
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - F Ortolano
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - F Triulzi
- Department of Neuroradiology, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - E R Zanier
- Department of Neuroscience, Laboratory of Acute Brain Injury and Therapeutic Strategies, IRCCS Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - T Zoerle
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - N Stocchetti
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
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10
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Hussain A, Steenbergen W, Vellekoop IM. Imaging blood flow inside highly scattering media using ultrasound modulated optical tomography. JOURNAL OF BIOPHOTONICS 2018; 11:e201700013. [PMID: 28681970 DOI: 10.1002/jbio.201700013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/30/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
We report the use of ultrasound modulated optical tomography (UOT) with heterodyne parallel detection to locally sense and image blood flow deep inside a highly scattering medium. We demonstrate that the UOT signal is sensitive to the speed of the blood flow in the ultrasound focus and present an analytical model that relates UOT signals to the optical properties (i. e. scattering coefficient, anisotropy, absorption, and flow speed) of the blood and the background medium. We found an excellent agreement between the experimental data and the analytical model. By varying the integration time of the camera in our setup, we were able to spatially resolve blood flow in a scattering medium with a lateral resolution of 1.5 mm.
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Affiliation(s)
- Altaf Hussain
- Biomedical Photonic Imaging group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Wiendelt Steenbergen
- Biomedical Photonic Imaging group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Ivo M Vellekoop
- Biomedical Photonic Imaging group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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11
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Fegley MW, Spelde A, Johnson D, Desai ND, Levy WJ. Malperfusion During Hypothermic Antegrade Cerebral Perfusion: Cerebral Perfusion Index-An Early Indicator Compared to Cerebral Oximetry. J Cardiothorac Vasc Anesth 2017; 32:1835-1837. [PMID: 29331552 DOI: 10.1053/j.jvca.2017.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Mark W Fegley
- Department of Anesthesiology and Critical Care, University of Pennsylvania Medical Center, Philadelphia, PA.
| | - Audrey Spelde
- Department of Anesthesiology and Critical Care, University of Pennsylvania Medical Center, Philadelphia, PA
| | - David Johnson
- Department of Anesthesiology and Critical Care, University of Pennsylvania Medical Center, Philadelphia, PA
| | - Nimesh D Desai
- Division of Cardiovascular Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Warren J Levy
- Department of Anesthesiology and Critical Care, University of Pennsylvania Medical Center, Philadelphia, PA
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12
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Tsalach A, Ratner E, Lokshin S, Silman Z, Breskin I, Budin N, Kamar M. Cerebral Autoregulation Real-Time Monitoring. PLoS One 2016; 11:e0161907. [PMID: 27571474 PMCID: PMC5003385 DOI: 10.1371/journal.pone.0161907] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 08/12/2016] [Indexed: 11/19/2022] Open
Abstract
Cerebral autoregulation is a mechanism which maintains constant cerebral blood flow (CBF) despite changes in mean arterial pressure (MAP). Assessing whether this mechanism is intact or impaired and determining its boundaries is important in many clinical settings, where primary or secondary injuries to the brain may occur. Herein we describe the development of a new ultrasound tagged near infra red light monitor which tracks CBF trends, in parallel, it continuously measures blood pressure and correlates them to produce a real time autoregulation index. Its performance is validated in both in-vitro experiment and a pre-clinical case study. Results suggest that using such a tool, autoregulation boundaries as well as its impairment or functioning can be identified and assessed. It may therefore assist in individualized MAP management to ensure adequate organ perfusion and reduce the risk of postoperative complications, and might play an important role in patient care.
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Affiliation(s)
- Adi Tsalach
- Ornim Medical Ltd, Kfar Saba, Israel
- * E-mail:
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13
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Fantini S, Sassaroli A, Tgavalekos KT, Kornbluth J. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods. NEUROPHOTONICS 2016; 3:031411. [PMID: 27403447 PMCID: PMC4914489 DOI: 10.1117/1.nph.3.3.031411] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/10/2016] [Indexed: 05/23/2023]
Abstract
Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.
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Affiliation(s)
- Sergio Fantini
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Kristen T. Tgavalekos
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Joshua Kornbluth
- Tufts University School of Medicine, Department of Neurology, Division of Neurocritical Care, 800 Washington Street, Box #314, Boston, Massachusetts 02111, United States
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Wang D, Parthasarathy AB, Baker WB, Gannon K, Kavuri V, Ko T, Schenkel S, Li Z, Li Z, Mullen MT, Detre JA, Yodh AG. Fast blood flow monitoring in deep tissues with real-time software correlators. BIOMEDICAL OPTICS EXPRESS 2016; 7:776-97. [PMID: 27231588 PMCID: PMC4866455 DOI: 10.1364/boe.7.000776] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 05/19/2023]
Abstract
We introduce, validate and demonstrate a new software correlator for high-speed measurement of blood flow in deep tissues based on diffuse correlation spectroscopy (DCS). The software correlator scheme employs standard PC-based data acquisition boards to measure temporal intensity autocorrelation functions continuously at 50 - 100 Hz, the fastest blood flow measurements reported with DCS to date. The data streams, obtained in vivo for typical source-detector separations of 2.5 cm, easily resolve pulsatile heart-beat fluctuations in blood flow which were previously considered to be noise. We employ the device to separate tissue blood flow from tissue absorption/scattering dynamics and thereby show that the origin of the pulsatile DCS signal is primarily flow, and we monitor cerebral autoregulation dynamics in healthy volunteers more accurately than with traditional instrumentation as a result of increased data acquisition rates. Finally, we characterize measurement signal-to-noise ratio and identify count rate and averaging parameters needed for optimal performance.
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Affiliation(s)
- Detian Wang
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
- Interdisciplinary Laboratory of Physics and Biomedicine, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900,
China
| | | | - Wesley B. Baker
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Kimberly Gannon
- Div. of Stroke and Neurocritical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Venki Kavuri
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Tiffany Ko
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Steven Schenkel
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Zhe Li
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072,
China
| | - Zeren Li
- Interdisciplinary Laboratory of Physics and Biomedicine, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900,
China
| | - Michael T. Mullen
- Div. of Stroke and Neurocritical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104
USA
| | - John A. Detre
- Div. of Stroke and Neurocritical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104
USA
| | - Arjun G. Yodh
- Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104
USA
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