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Mazumder D, Wu MM, Ozana N, Tamborini D, Franceschini MA, Carp SA. Optimization of time domain diffuse correlation spectroscopy parameters for measuring brain blood flow. NEUROPHOTONICS 2021; 8:035005. [PMID: 34395719 PMCID: PMC8358828 DOI: 10.1117/1.nph.8.3.035005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/15/2021] [Indexed: 05/05/2023]
Abstract
Significance: Time domain diffuse correlation spectroscopy (TD-DCS) can offer increased sensitivity to cerebral hemodynamics and reduced contamination from extracerebral layers by differentiating photons based on their travel time in tissue. We have developed rigorous simulation and evaluation procedures to determine the optimal time gate parameters for monitoring cerebral perfusion considering instrumentation characteristics and realistic measurement noise. Aim: We simulate TD-DCS cerebral perfusion monitoring performance for different instrument response functions (IRFs) in the presence of realistic experimental noise and evaluate metrics of sensitivity to brain blood flow, signal-to-noise ratio (SNR), and ability to reject the influence of extracerebral blood flow across a variety of time gates to determine optimal operating parameters. Approach: Light propagation was modeled on an MRI-derived human head geometry using Monte Carlo simulations for 765- and 1064-nm excitation wavelengths. We use a virtual probe with a source-detector separation of 1 cm placed in the pre-frontal region. Performance metrics described above were evaluated to determine optimal time gate(s) for different IRFs. Validation of simulation noise estimates was done with experiments conducted on an intralipid-based liquid phantom. Results: We find that TD-DCS performance strongly depends on the system IRF. Among Gaussian pulse shapes, ∼ 300 ps pulse length appears to offer the best performance, at wide gates (500 ps and larger) with start times 400 and 600 ps after the peak of the TPSF at 765 and 1064 nm, respectively, for a 1-s integration time at photon detection rates seen experimentally (600 kcps at 765 nm and 4 Mcps at 1064 nm). Conclusions: Our work shows that optimal time gates satisfy competing requirements for sufficient sensitivity and sufficient SNR. The achievable performance is further impacted by system IRF with ∼ 300 ps quasi-Gaussian pulse obtained using electro-optic laser shaping providing the best results.
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Affiliation(s)
- Dibbyan Mazumder
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
- Address all correspondence to Dibbyan Mazumder,
| | - Melissa M. Wu
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Nisan Ozana
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Davide Tamborini
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Maria Angela Franceschini
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Stefan A. Carp
- Harvard Medical School, Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
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Wu KC, Sunwoo J, Sheriff F, Farzam P, Farzam PY, Orihuela-Espina F, LaRose SL, Monk AD, Aziz-Sultan MA, Patel N, Vaitkevicius H, Franceschini MA. Validation of diffuse correlation spectroscopy measures of critical closing pressure against transcranial Doppler ultrasound in stroke patients. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200360R. [PMID: 33774980 PMCID: PMC7998065 DOI: 10.1117/1.jbo.26.3.036008] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/08/2021] [Indexed: 05/25/2023]
Abstract
SIGNIFICANCE Intracranial pressure (ICP), variability in perfusion, and resulting ischemia are leading causes of secondary brain injury in patients treated in the neurointensive care unit. Continuous, accurate monitoring of cerebral blood flow (CBF) and ICP guide intervention and ultimately reduce morbidity and mortality. Currently, only invasive tools are used to monitor patients at high risk for intracranial hypertension. AIM Diffuse correlation spectroscopy (DCS), a noninvasive near-infrared optical technique, is emerging as a possible method for continuous monitoring of CBF and critical closing pressure (CrCP or zero-flow pressure), a parameter directly related to ICP. APPROACH We optimized DCS hardware and algorithms for the quantification of CrCP. Toward its clinical translation, we validated the DCS estimates of cerebral blood flow index (CBFi) and CrCP in ischemic stroke patients with respect to simultaneously acquired transcranial Doppler ultrasound (TCD) cerebral blood flow velocity (CBFV) and CrCP. RESULTS We found CrCP derived from DCS and TCD were highly linearly correlated (ipsilateral R2 = 0.77, p = 9 × 10 - 7; contralateral R2 = 0.83, p = 7 × 10 - 8). We found weaker correlations between CBFi and CBFV (ipsilateral R2 = 0.25, p = 0.03; contralateral R2 = 0.48, p = 1 × 10 - 3) probably due to the different vasculature measured. CONCLUSION Our results suggest DCS is a valid alternative to TCD for continuous monitoring of CrCP.
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Affiliation(s)
- Kuan-Cheng Wu
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - John Sunwoo
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Faheem Sheriff
- Brigham and Women’s Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Parisa Farzam
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Parya Y. Farzam
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Felipe Orihuela-Espina
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
- National Institute for Astrophysics Optics and Electronics, Department of Computational Sciences, Puebla, Mexico
| | - Sarah L. LaRose
- Brigham and Women’s Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Andrew D. Monk
- Brigham and Women’s Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Mohammad A. Aziz-Sultan
- Brigham and Women’s Hospital, Department of Neurosurgery, Boston, Massachusetts, United States
| | - Nirav Patel
- Brigham and Women’s Hospital, Department of Neurosurgery, Boston, Massachusetts, United States
| | - Henrikas Vaitkevicius
- Brigham and Women’s Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital and Harvard Medical School, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
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Delay of cerebral autoregulation in traumatic brain injury patients. Clin Neurol Neurosurg 2021; 202:106478. [PMID: 33454499 DOI: 10.1016/j.clineuro.2021.106478] [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: 10/07/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Adequate cerebral perfusion prevents secondary insult after traumatic brain injury (TBI). Cerebral autoregulation (CAR) keeps cerebral blood flow (CBF) constant when arterial blood pressure (ABP) changes. Aim of the study was to evaluate the existence of delayed CAR in TBI patients and its possible association with outcome. METHODS We retrospectively analysed TBI patients. Flow velocity (FV) in middle cerebral artery, invasive intra-cranial pressure (ICP) and ABP were recorded. Cerebral perfusion pressure (CPP) was calculated as ABP - ICP. Mean flow index (Mx) > 0.3 defined altered CAR. Samples from patients with altered CAR were further analysed: FV signal was shifted backward relative to CPP; Mx was calculated after each shift (MxD). Mx > 0.3 plus MxD ≤ 0.3 defined delayed CAR. Favourable outcome (FO) at 6 months was defined as Glasgow Outcome Scale 4-5. RESULTS 154 patients were included. GCS was 6 [4-9], ICP was 14 [9-20] mmHg. Data on 6 months outcome were available for 131 patients: 104/131 patients (79 %) were alive; GOS was 4 [3-5]; 70/131 (53 %) had FO. Mx was 0.07 [-0.19 to 0.28] overall. Mx was lower in patients with FO compared others (0.00 [-0.21 to 0.20] vs 0.17 [-0.12 to 0.37], p = 0.02). 118 (77 %) patients had intact CAR and 36 (23 %) patients had altered CAR; 23 patients - 15 % of the general cohort and 64 % of patients with altered CAR - had delayed CAR. Delay in the autoregulatory response was 2 [1-4] seconds. 80/98 (82 %) of patients with intact CAR survived, compared to 16/21 (76 %) with delayed and 8/12 (67 %) with altered CAR (p = 0.20). 80/98 (58 %) patients with intact, 10/21 (48 %) patients with delayed and 3/12 (25 %) patients with altered CAR had FO (p = 0.03). CONCLUSION A subgroup of TBI patients with delayed CAR was identified. Delayed CAR was associated with better neurological outcome than altered CAR.
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Lyson T, Sieskiewicz A, Rutkowski R, Rybaczek M, Sobolewski A, Gorbacz K, Krajewski J, Kochanowicz J, Rogowski M, Mariak Z. Brain tissue oxygenation during transnasal endoscopic skull base procedures. Adv Med Sci 2020; 65:286-290. [PMID: 32361485 DOI: 10.1016/j.advms.2020.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/19/2020] [Accepted: 03/23/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE We aimed to study brain tissue oxygenation during the period of controlled reduction of arterial blood pressure - a maneuver often used in extended endoscopic skull base surgery for bloodless operative field. METHODS Intracranial pressure, arterial blood pressure and the resultant cerebral perfusion pressure were measured during extended endoscopic skull base surgery in 5 patients with diagnosed tumors of the skull base and arterial hypertension. Simultaneously, in those patients, we measured partial pressure of oxygen in the brain parenchyma (PbtO2). RESULTS Values of PbtO2 lower than 15 mm Hg (risk of brain ischemia) were observed in 3 patients for periods of 40 min, 110 min and 123 min, respectively. In 2 of these patients, no hypotension (mean arterial pressure <65 mm Hg) was necessary for bloodless operative field. Another 2 patients had PbtO2 above 30 mm Hg at the time when their mean arterial pressure was below 65 mm Hg. The time course of PbtO2 followed that of cerebral perfusion pressure with a time lag of 40-60 s in all patients. CONCLUSION Moderate reduction of arterial pressure, often used to obtain bloodless operative field during extended endoscopic skull base surgery, may in patients with the medical history of arterial hypertension be associated with critically low values of partial oxygen pressure in brain tissue.
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Tamborini D, Stephens KA, Wu MM, Farzam P, Siegel AM, Shatrovoy O, Blackwell M, Boas DA, Carp SA, Franceschini MA. Portable System for Time-Domain Diffuse Correlation Spectroscopy. IEEE Trans Biomed Eng 2019; 66:3014-3025. [PMID: 30794161 PMCID: PMC7216142 DOI: 10.1109/tbme.2019.2899762] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We introduce a portable system for clinical studies based on time-domain diffuse correlation spectroscopy (DCS). After evaluating different lasers and detectors, the final system is based on a pulsed laser with about 550 ps pulsewidth, a coherence length of 38 mm, and two types of single-photon avalanche diodes (SPAD). The higher efficiency of the red-enhanced SPAD maximizes detection of the collected light, increasing the signal-to-noise ratio, while the better timing response of the CMOS SPAD optimizes the selection of late photons and increases spatial resolution. We discuss component selection and performance, and we present a full characterization of the system, measurement stability, a phantom-based validation study, and preliminary in vivo results collected from the forearms and the foreheads of four healthy subjects. With this system, we are able to resolve blood flow changes 1 cm below the skin surface with improved depth sensitivity and spatial resolution with respect to continuous wave DCS.
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Correlation between Glasgow coma scale and Jugular venous oxygen saturation in severe traumatic brain injury. EGYPTIAN JOURNAL OF ANAESTHESIA 2019. [DOI: 10.1016/j.egja.2013.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Selb J, Wu KC, Sutin J, Lin PY(I, Farzam P, Bechek S, Shenoy A, Patel AB, Boas DA, Franceschini MA, Rosenthal ES. Prolonged monitoring of cerebral blood flow and autoregulation with diffuse correlation spectroscopy in neurocritical care patients. NEUROPHOTONICS 2018; 5:045005. [PMID: 30450363 PMCID: PMC6233866 DOI: 10.1117/1.nph.5.4.045005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 09/24/2018] [Indexed: 05/13/2023]
Abstract
Monitoring of cerebral blood flow (CBF) and autoregulation are essential components of neurocritical care, but continuous noninvasive methods for CBF monitoring are lacking. Diffuse correlation spectroscopy (DCS) is a noninvasive diffuse optical modality that measures a CBF index ( CBF i ) in the cortex microvasculature by monitoring the rapid fluctuations of near-infrared light diffusing through moving red blood cells. We tested the feasibility of monitoring CBF i with DCS in at-risk patients in the Neurosciences Intensive Care Unit. DCS data were acquired continuously for up to 20 h in six patients with aneurysmal subarachnoid hemorrhage, as permitted by clinical care. Mean arterial blood pressure was recorded synchronously, allowing us to derive autoregulation curves and to compute an autoregulation index. The autoregulation curves suggest disrupted cerebral autoregulation in most patients, with the severity of disruption and the limits of preserved autoregulation varying between subjects. Our findings suggest the potential of the DCS modality for noninvasive, long-term monitoring of cerebral perfusion, and autoregulation.
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Affiliation(s)
- Juliette Selb
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Kuan-Cheng Wu
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Jason Sutin
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Pei-Yi (Ivy) Lin
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Parisa Farzam
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Sophia Bechek
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Apeksha Shenoy
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - Aman B. Patel
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
| | - David A. Boas
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Optics at Martinos, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States
- Address all correspondence to: Maria Angela Franceschini, E-mail:
| | - Eric S. Rosenthal
- Massachusetts General Hospital, Department of Neurology, Boston, Massachusetts, United States
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Vinke EJ, Kortenbout AJ, Eyding J, Slump CH, van der Hoeven JG, de Korte CL, Hoedemaekers CWE. Potential of Contrast-Enhanced Ultrasound as a Bedside Monitoring Technique in Cerebral Perfusion: a Systematic Review. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2751-2757. [PMID: 28964614 DOI: 10.1016/j.ultrasmedbio.2017.08.935] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/10/2017] [Accepted: 08/13/2017] [Indexed: 06/07/2023]
Abstract
Contrast-enhanced ultrasound (CEUS) has been suggested as a new method to measure cerebral perfusion in patients with acute brain injury. In this systematic review, the tolerability, repeatability, reproducibility and accuracy of different CEUS techniques for the quantification of cerebral perfusion were assessed. We selected studies published between January 1994 and March 2017 using CEUS to measure cerebral perfusion. We included 43 studies (bolus kinetics n = 31, refill kinetics n = 6, depletion kinetics n = 6) with a total of 861 patients. Tolerability was reported in 28 studies describing 12 patients with mild and transient side effects. Repeatability was assessed in 3 studies, reproducibility in 2 studies and accuracy in 19 studies. Repeatability was high for experienced sonographers and significantly lower for less experienced sonographers. Reproducibility of CEUS was not clear. The sensitivity and specificity of CEUS for the detection of cerebral ischemia ranged from 75% to 96% and from 60% to 100%. Limited data on repeatability, reproducibility and accuracy may suggest that this technique could be feasible for use in acute brain injury patients.
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Affiliation(s)
- Elisabeth J Vinke
- Department of Intensive Care, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Anna J Kortenbout
- Department of Intensive Care, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Jens Eyding
- Department of Neurology, Sana-Klinikum Remscheid and University Hospital Knappschaftskrankenhaus, Ruhr University, Bochum, Germany
| | - Cornelis H Slump
- Department of Technical Medicine, University of Twente, Enschede, The Netherlands
| | | | - Chris L de Korte
- Medical Ultrasound Imaging Center, Department of Radiology, Radboud University Medical Center, Nijmegen, The Netherlands
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Stadler KL, Pease AP, Ballegeer EA. Dynamic Susceptibility Contrast Magnetic Resonance Imaging Protocol of the Normal Canine Brain. Front Vet Sci 2017; 4:41. [PMID: 28377923 PMCID: PMC5359224 DOI: 10.3389/fvets.2017.00041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/07/2017] [Indexed: 01/06/2023] Open
Abstract
Perfusion magnetic resonance imaging (MRI), specifically dynamic susceptibility MRI (DSC-MRI) is routinely performed as a supplement to conventional MRI in human medicine for patients with intracranial neoplasia and cerebrovascular events. There is minimal data on the use of DSC-MRI in veterinary patients and a DSC-MRI protocol in the veterinary patient has not been described. Sixteen normal dogs, 6 years or older were recruited for this study. The sample population included 11 large dogs (>11 kg) and 5 small dogs (<11 kg). DSC-MRI was performed on a 1.5-T MRI using an adjusted protocol inherent to the MRI. Contrast media was injected using an automatic power injector. Injections were made after five MR measurements were obtained. Following image acquisition, an arterial input function (AIF) graph mapping the transit time of contrast within the cerebral arteries was generated. The manually selected time points along this graph were used to compute perfusion maps. A dose and rate of 0.1 mmol/kg gadolinium-based contrast media at 3 ml/s followed by 10 ml saline flush at 3 ml/s was used in all dogs greater than 11 kg. In all dogs >11 kg, a useable AIF and perfusion map was generated. One dog less than 11 kg received the same contrast dose and rate. In this patient, the protocol did not generate a useable AIF. The remainder of the dogs less than 11 kg followed a protocol of 0.2 mmol/kg gadolinium-based contrast media at 1.5 ml/s with a 10 ml saline flush at 1.5 ml/s. A useable AIF and perfusion map was generated in the remaining dogs <11 kg using the higher contrast dose and slower rate protocol. This study establishes a contrast dose and administration rate for canine DSC-MRI imaging that is different in dogs greater than 11 kg compared to dogs less than 11 kg. These protocols may be used for future applications to evaluate hemodynamic disturbances in canine intracranial pathology.
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Affiliation(s)
- Krystina L Stadler
- Department of Small Animal Clinical Sciences, Michigan State University College of Veterinary Medicine , East Lansing, MI , USA
| | - Anthony P Pease
- Department of Small Animal Clinical Sciences, Michigan State University College of Veterinary Medicine , East Lansing, MI , USA
| | - Elizabeth A Ballegeer
- Department of Small Animal Clinical Sciences, Michigan State University College of Veterinary Medicine , East Lansing, MI , USA
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On-site Rapid Diagnosis of Intracranial Hematoma using Portable Multi-slice Microwave Imaging System. Sci Rep 2016; 6:37620. [PMID: 27897197 PMCID: PMC5126641 DOI: 10.1038/srep37620] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/01/2016] [Indexed: 11/28/2022] Open
Abstract
Rapid, on-the-spot diagnostic and monitoring systems are vital for the survival of patients with intracranial hematoma, as their conditions drastically deteriorate with time. To address the limited accessibility, high costs and static structure of currently used MRI and CT scanners, a portable non-invasive multi-slice microwave imaging system is presented for accurate 3D localization of hematoma inside human head. This diagnostic system provides fast data acquisition and imaging compared to the existing systems by means of a compact array of low-profile, unidirectional antennas with wideband operation. The 3D printed low-cost and portable system can be installed in an ambulance for rapid on-site diagnosis by paramedics. In this paper, the multi-slice head imaging system’s operating principle is numerically analysed and experimentally validated on realistic head phantoms. Quantitative analyses demonstrate that the multi-slice head imaging system is able to generate better quality reconstructed images providing 70% higher average signal to clutter ratio, 25% enhanced maximum signal to clutter ratio and with around 60% hematoma target localization compared to the previous head imaging systems. Nevertheless, numerical and experimental results demonstrate that previous reported 2D imaging systems are vulnerable to localization error, which is overcome in the presented multi-slice 3D imaging system. The non-ionizing system, which uses safe levels of very low microwave power, is also tested on human subjects. Results of realistic phantom and subjects demonstrate the feasibility of the system in future preclinical trials.
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Goodson CM, Rosenblatt K, Rivera-Lara L, Nyquist P, Hogue CW. Cerebral Blood Flow Autoregulation in Sepsis for the Intensivist: Why Its Monitoring May Be the Future of Individualized Care. J Intensive Care Med 2016; 33:63-73. [PMID: 27798314 DOI: 10.1177/0885066616673973] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.
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Affiliation(s)
- Carrie M Goodson
- 1 Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kathryn Rosenblatt
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lucia Rivera-Lara
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Paul Nyquist
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles W Hogue
- 4 Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Noninvasive Measurement of Cerebral Blood Flow Under Anesthesia Using Arterial Spin Labeling MRI: A Pilot Study. J Neurosurg Anesthesiol 2016; 28:331-6. [DOI: 10.1097/ana.0000000000000231] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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13
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Sutin J, Zimmerman B, Tyulmankov D, Tamborini D, Wu KC, Selb J, Gulinatti A, Rech I, Tosi A, Boas DA, Franceschini MA. Time-domain diffuse correlation spectroscopy. OPTICA 2016; 3:1006-1013. [PMID: 28008417 PMCID: PMC5166986 DOI: 10.1364/optica.3.001006] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Physiological monitoring of oxygen delivery to the brain has great significance for improving the management of patients at risk for brain injury. Diffuse correlation spectroscopy (DCS) is a rapidly growing optical technology able to non-invasively assess the blood flow index (BFi) at the bedside. The current limitations of DCS are the contamination introduced by extracerebral tissue and the need to know the tissue's optical properties to correctly quantify the BFi. To overcome these limitations, we have developed a new technology for time-resolved diffuse correlation spectroscopy. By operating DCS in the time domain (TD-DCS), we are able to simultaneously acquire the temporal point-spread function to quantify tissue optical properties and the autocorrelation function to quantify the BFi. More importantly, by applying time-gated strategies to the DCS autocorrelation functions, we are able to differentiate between short and long photon paths through the tissue and determine the BFi for different depths. Here, we present the novel device and we report the first experiments in tissue-like phantoms and in rodents. The TD-DCS method opens many possibilities for improved non-invasive monitoring of oxygen delivery in humans.
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Affiliation(s)
- Jason Sutin
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Bernhard Zimmerman
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Danil Tyulmankov
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Davide Tamborini
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Dipartimento di Elettronica, Informazione e Bioingegneria at Politecnico di Milano, Milano, Italy
| | - Kuan Cheng Wu
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Juliette Selb
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Angelo Gulinatti
- Dipartimento di Elettronica, Informazione e Bioingegneria at Politecnico di Milano, Milano, Italy
| | - Ivan Rech
- Dipartimento di Elettronica, Informazione e Bioingegneria at Politecnico di Milano, Milano, Italy
| | - Alberto Tosi
- Dipartimento di Elettronica, Informazione e Bioingegneria at Politecnico di Milano, Milano, Italy
| | - David A. Boas
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Maria Angela Franceschini
- Optics Division at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Corresponding author:
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14
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Dolui S, Wang Z, Wang DJJ, Mattay R, Finkel M, Elliott M, Desiderio L, Inglis B, Mueller B, Stafford RB, Launer LJ, Jacobs DR, Bryan RN, Detre JA. Comparison of non-invasive MRI measurements of cerebral blood flow in a large multisite cohort. J Cereb Blood Flow Metab 2016; 36:1244-56. [PMID: 27142868 PMCID: PMC4929707 DOI: 10.1177/0271678x16646124] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/22/2016] [Indexed: 11/16/2022]
Abstract
UNLABELLED Arterial spin labeling and phase contrast magnetic resonance imaging provide independent non-invasive methods for measuring cerebral blood flow. We compared global cerebral blood flow measurements obtained using pseudo-continuous arterial spin labeling and phase contrast in 436 middle-aged subjects acquired at two sites in the NHLBI CARDIA multisite study. Cerebral blood flow measured by phase contrast (CBFPC: 55.76 ± 12.05 ml/100 g/min) was systematically higher (p < 0.001) and more variable than cerebral blood flow measured by pseudo-continuous arterial spin labeling (CBFPCASL: 47.70 ± 9.75). The correlation between global cerebral blood flow values obtained from the two modalities was 0.59 (p < 0.001), explaining less than half of the observed variance in cerebral blood flow estimates. Well-established correlations of global cerebral blood flow with age and sex were similarly observed in both CBFPCASL and CBFPC CBFPC also demonstrated statistically significant site differences, whereas no such differences were observed in CBFPCASL No consistent velocity-dependent effects on pseudo-continuous arterial spin labeling were observed, suggesting that pseudo-continuous labeling efficiency does not vary substantially across typical adult carotid and vertebral velocities, as has previously been suggested. CONCLUSIONS Although CBFPCASL and CBFPC values show substantial similarity across the entire cohort, these data do not support calibration of CBFPCASL using CBFPC in individual subjects. The wide-ranging cerebral blood flow values obtained by both methods suggest that cerebral blood flow values are highly variable in the general population.
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Affiliation(s)
- Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA
| | - Ze Wang
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Hangzhou, China Departments of Psychiatry and Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Danny J J Wang
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Raghav Mattay
- Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mack Finkel
- School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Elliott
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa Desiderio
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ben Inglis
- Henry H. Wheeler Jr. Brain Imaging Center, University of California, Berkeley, CA, USA
| | - Bryon Mueller
- Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA
| | - Randall B Stafford
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Lenore J Launer
- Laboratory of Epidemiology and Population Science, National Institute on Aging, Bethesda, MD, USA
| | - David R Jacobs
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - R Nick Bryan
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA
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15
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Wang Q, Fan W, Cai Y, Wu Q, Mo L, Huang Z, Huang H. Protective effects of taurine in traumatic brain injury via mitochondria and cerebral blood flow. Amino Acids 2016; 48:2169-77. [PMID: 27156064 DOI: 10.1007/s00726-016-2244-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/25/2016] [Indexed: 12/12/2022]
Abstract
In mammalian tissues, taurine is an important natural component and the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. This study is to examine the taurine's protective effects on neuronal ultrastructure, the function of the mitochondrial respiratory chain complex, and on cerebral blood flow (CBF). The model of traumatic brain injury (TBI) was made for SD rats by a fluid percussion device, with taurine (200 mg/kg) administered by tail intravenous injection once daily for 7 days after TBI. It was found that CBF was improved for both left and right brain at 30 min and 7 days post-injury by taurine. Reaction time was prolonged relative to the TBI-only group. Neuronal damage was prevented by 7 days taurine. Mitochondrial electron transport chain complexes I and II showed greater activity with the taurine group. The improvement by taurine of CBF may alleviate edema and elevation in intracranial pressure. Importantly taurine improved the hypercoagulable state.
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Affiliation(s)
- Qin Wang
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing, 100050, China.,Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China
| | - Weijia Fan
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China
| | - Ying Cai
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China
| | - Qiaoli Wu
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China
| | - Lidong Mo
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China
| | - Zhenwu Huang
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing, 100050, China
| | - Huiling Huang
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurological Institute, Tianjin Huanhu Hospital, No. 6 Jizhao Road, Jinnan District, Tianjin, 300350, China.
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16
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Oziel M, Hjouj M, Gonzalez CA, Lavee J, Rubinsky B. Non-ionizing radiofrequency electromagnetic waves traversing the head can be used to detect cerebrovascular autoregulation responses. Sci Rep 2016; 6:21667. [PMID: 26898944 PMCID: PMC4761952 DOI: 10.1038/srep21667] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 01/26/2016] [Indexed: 11/25/2022] Open
Abstract
Monitoring changes in non-ionizing radiofrequency electromagnetic waves as they traverse the brain can detect the effects of stimuli employed in cerebrovascular autoregulation (CVA) tests on the brain, without contact and in real time. CVA is a physiological phenomenon of importance to health, used for diagnosis of a number of diseases of the brain with a vascular component. The technology described here is being developed for use in diagnosis of injuries and diseases of the brain in rural and economically underdeveloped parts of the world. A group of nine subjects participated in this pilot clinical evaluation of the technology. Substantial research remains to be done on correlating the measurements with physiology and anatomy.
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Affiliation(s)
- M. Oziel
- Faculty of Life Science, Bar Ilan University, Israel
| | - M. Hjouj
- Medical Imaging Department, Al-Quds University, Abu Dis, Palestine
| | - C. A. Gonzalez
- Instituto Politécnico Nacional-Escuela Superior de Medicina, DF, Mexico
- Universidad del Ejército y Fuerza Aérea-EMGS, DF, Mexico
| | - J. Lavee
- Faculty of Life Science, Bar Ilan University, Israel
- Heart Transplantation Unit, Department of Cardiac Surgery, Leviev Heart Center, Sheba Medical Center, Ramat Gan, Israel
| | - B. Rubinsky
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720 USA
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17
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Li C, Wu PM, Wu Z, Limnuson K, Mehan N, Mozayan C, Golanov EV, Ahn CH, Hartings JA, Narayan RK. Highly accurate thermal flow microsensor for continuous and quantitative measurement of cerebral blood flow. Biomed Microdevices 2015; 17:87. [DOI: 10.1007/s10544-015-9992-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Mundiyanapurath S, Schönenberger S, Rosales ML, Carrilho Romeiro AM, Möhlenbruch M, Bendszus M, Hacke W, Bösel J. Circulatory and Respiratory Parameters during Acute Endovascular Stroke Therapy in Conscious Sedation or General Anesthesia. J Stroke Cerebrovasc Dis 2015; 24:1244-9. [DOI: 10.1016/j.jstrokecerebrovasdis.2015.01.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/09/2015] [Accepted: 01/22/2015] [Indexed: 11/29/2022] Open
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19
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Ha TN, van Renen RG, Ludbrook GL, Valentine R, Ou J, Wormald P. The relationship between hypotension, cerebral flow, and the surgical field during endoscopic sinus surgery. Laryngoscope 2014; 124:2224-30. [DOI: 10.1002/lary.24664] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/04/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Thanh Ngoc Ha
- Department of Surgery–Otolaryngology Head and Neck SurgeryThe University of AdelaideAdelaide Australia
| | | | - Guy L. Ludbrook
- Discipline of Acute Care MedicineThe University of AdelaideAdelaide Australia
| | - Rowan Valentine
- Department of Surgery–Otolaryngology Head and Neck SurgeryThe University of AdelaideAdelaide Australia
| | - Judy Ou
- Department of Surgery–Otolaryngology Head and Neck SurgeryThe University of AdelaideAdelaide Australia
| | - Peter‐John Wormald
- Department of Surgery–Otolaryngology Head and Neck SurgeryThe University of AdelaideAdelaide Australia
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20
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Acocello S, Broshek DK, Saliba S. Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor. J Neurosci Methods 2014; 221:85-91. [DOI: 10.1016/j.jneumeth.2013.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/26/2013] [Accepted: 09/08/2013] [Indexed: 01/26/2023]
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21
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Andrade AFD, Soares MS, Patriota GC, Belon AR, Paiva WS, Bor-Seng-Shu E, Oliveira MDL, Nascimento CN, Noleto GS, Alves Junior AC, Figueiredo EG, Otoch JP, Teixeira MJ. Experimental model of intracranial hypertension with continuous multiparametric monitoring in swine. ARQUIVOS DE NEURO-PSIQUIATRIA 2013; 71:802-6. [DOI: 10.1590/0004-282x20130126] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/31/2013] [Indexed: 11/21/2022]
Abstract
Objective Intracranial hypertension (IH) develops in approximately 50% of all patients with severe traumatic brain injury (TBI). Therefore, it is very important to identify a suitable animal model to study and understand the pathophysiology of refractory IH to develop effective treatments. Methods We describe a new experimental porcine model designed to simulate expansive brain hematoma causing IH. Under anesthesia, IH was simulated with a balloon insufflation. The IH variables were measured with intracranial pressure (ICP) parenchymal monitoring, epidural, cerebral oximetry, and transcranial Doppler (TCD). Results None of the animals died during the experiment. The ICP epidural showed a slower rise compared with parenchymal ICP. We found a correlation between ICP and cerebral oximetry. Conclusion The model described here seems useful to understand some of the pathophysiological characteristics of acute IH.
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22
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Bor-Seng-Shu E, Kita WS, Figueiredo EG, Paiva WS, Fonoff ET, Teixeira MJ, Panerai RB. Cerebral hemodynamics: concepts of clinical importance. ARQUIVOS DE NEURO-PSIQUIATRIA 2012; 70:352-6. [PMID: 22618788 DOI: 10.1590/s0004-282x2012000500010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 12/06/2011] [Indexed: 11/22/2022]
Abstract
Cerebral hemodynamics and metabolism are frequently impaired in a wide range of neurological diseases, including traumatic brain injury and stroke, with several pathophysiological mechanisms of injury. The resultant uncoupling of cerebral blood flow and metabolism can trigger secondary brain lesions, particularly in early phases, consequently worsening the patient's outcome. Cerebral blood flow regulation is influenced by blood gas content, blood viscosity, body temperature, cardiac output, altitude, cerebrovascular autoregulation, and neurovascular coupling, mediated by chemical agents such as nitric oxide (NO), carbon monoxide (CO), eicosanoid products, oxygen-derived free radicals, endothelins, K+, H+, and adenosine. A better understanding of these factors is valuable for the management of neurocritical care patients. The assessment of both cerebral hemodynamics and metabolism in the acute phase of neurocritical care conditions may contribute to a more effective planning of therapeutic strategies for reducing secondary brain lesions. In this review, the authors have discussed concepts of cerebral hemodynamics, considering aspects of clinical importance.
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Affiliation(s)
- Edson Bor-Seng-Shu
- Division of Neurological Surgery, Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, SP, Brazil.
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23
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Schytz HW, Guo S, Jensen LT, Kamar M, Nini A, Gress DR, Ashina M. A new technology for detecting cerebral blood flow: a comparative study of ultrasound tagged NIRS and 133Xe-SPECT. Neurocrit Care 2012; 17:139-45. [PMID: 22610823 DOI: 10.1007/s12028-012-9720-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
There is a need for real-time non-invasive, continuous monitoring of cerebral blood flow (CBF) during surgery, in intensive care units and clinical research. We investigated a new non-invasive hybrid technology employing ultrasound tagged near infrared spectroscopy (UT-NIRS) that may estimate changes in CBF using a cerebral blood flow index (CFI). Changes over time for UT-NIRS CFI and 133Xenon single photon emission computer tomography (133Xe-SPECT) CBF data were assessed in 10 healthy volunteers after an intravenous bolus of acetazolamide. UT-NIRS CFI was measured continuously and SPECT CBF was measured at baseline, 15 and 60 min after acetazolamide. We found significant changes over time in CFI by UT-NIRS and CBF by SPECT after acetazolamide (P ≤ 0.001). Post hoc tests showed a significant increase in CFI (P = 0.011) and SPECT CBF (P < 0.001) at 15 min after acetazolamide injection. There was a significant correlation between CFI and SPECT CBF values (r = 0.67 and P ≤ 0.033) at 15 min, but not at 60 min (P ≥ 0.777). UT-NIRS detected an increase in CFI following an acetazolamide bolus, which correlated with CBF measured with 133Xe-SPECT. This study demonstrates that UT-NIRS technology may be a promising new technique for non-invasive and real-time bedside CBF monitoring.
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Affiliation(s)
- Henrik W Schytz
- Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, 2600, Glostrup, Denmark.
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24
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Zweifel C, Czosnyka M, Carrera E, de Riva N, Pickard JD, Smielewski P. Reliability of the Blood Flow Velocity Pulsatility Index for Assessment of Intracranial and Cerebral Perfusion Pressures in Head-Injured Patients. Neurosurgery 2012; 71:853-61. [DOI: 10.1227/neu.0b013e3182675b42] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
It has been postulated that the Gosling pulsatility index (PI) assessed with transcranial Doppler (TCD) has a diagnostic value for noninvasive estimation of intracranial pressure (ICP) and cerebral perfusion pressure (CPP).
OBJECTIVE:
To revisit this hypothesis with the use of a database of digitally stored signals from a cohort of head-injured patients.
METHODS:
We analyzed prospectively collected data of patients admitted to the Cambridge Neuroscience critical care unit who had continuous recordings of arterial blood pressure, ICP, and cerebral blood flow velocities (FVs) using TCD. PI was calculated (FVsys − FVdia)/FVmean over each recording session. Statistical analysis was performed using Spearman rank correlation, receiver-operator-characteristics methods, and modeling of a nonlinear PI-ICP/CPP graph.
RESULTS:
Seven hundred sixty-two recorded daily sessions from 290 patients were analyzed with a total recording time of 499.9 hours. The correlation between PI and ICP was 0.31 (P < .001) and for PI and CPP -0.41 (P < .001). The 95% prediction interval of ICP values for a given PI was more than ±15 mm Hg and for CPP more than ±25 mm Hg. The diagnostic value of PI to assess ICP area under the curve ranged from 0.62 (ICP >15 mm Hg) to 0.74 (ICP >35 mm Hg). For CPP, the area under the curve ranged from 0.68 (CPP <70 mm Hg) to 0.81 (CPP <50 mm Hg). Probability charts for elevated ICP/lowered CPP depending on PI were created.
CONCLUSION:
Overall, the value of TCD-PI to assess ICP and CPP noninvasively is very limited. However, extreme values of PI can still potentially be used in support of a decision for invasive ICP monitoring.
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Affiliation(s)
- Christian Zweifel
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
- Department of Neurosurgery, University Hospital of Basel, Basel, Switzerland
| | - Marek Czosnyka
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
| | - Emmanuel Carrera
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
| | - Nicolas de Riva
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
| | - John D. Pickard
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
| | - Peter Smielewski
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom
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25
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Abstract
This article presents an overview of the management of traumatic brain injury (TBI) as relevant to the practicing anesthesiologist. Key concepts surrounding the pathophysiology and anesthetic principles are used to describe potential ways to reduce secondary insults and improve outcomes after TBI.
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26
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Abstract
This article presents an overview of intracranial monitoring techniques during the perioperative and intensive care management of neurologic patients. Various regional and global brain monitors are available; some modalities are well established whereas others are new to the clinical arena and their indications are still being evaluated. Indications for monitoring are reviewed, modalities critically evaluated, and future directions identified.
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Affiliation(s)
- Matthew A Kirkman
- The National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London, UK
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27
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Micromachined lab-on-a-tube sensors for simultaneous brain temperature and cerebral blood flow measurements. Biomed Microdevices 2012; 14:759-68. [DOI: 10.1007/s10544-012-9646-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Hayempour BJ, Rushing SE, Alavi A. The Role of Neuroimaging in Assessing Neuropsychological Deficits following Traumatic Brain Injury. ACTA ACUST UNITED AC 2011. [DOI: 10.1177/009318531103900403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neuroimaging enables highly accurate and specific identification of treatable brain injuries for the purposes of preventing secondary damage as well as providing useful prognostic information. This article addresses the range of currently employed neuroimaging techniques and their utility in assessing legal claims involving the presence of brain damage.
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