Journal articles on the topic 'Transcranial tissue Doppler'
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Rock, Erwin H. "Vascular Dizziness and Transcranial Doppler Ultrasonography." Annals of Otology, Rhinology & Laryngology 98, no. 7_suppl (July 1989): 3–23. http://dx.doi.org/10.1177/00034894890980s701.
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Dizziness as defined herein will include an illusion of motion caused by various degrees of ischemia to the vestibular pathway or its interconnecting pathways. “Syndrome,” such as the lateral medullary syndrome, denotes a macroinfarct, while a microinfarct or an area of incomplete infarct (where there may develop an incomplete degeneration of the neural tissue secondary to the arteriolar microatheromatous stenosis) may cause only one neurologic deficit, such as dizziness per se as the only symptom. However, the latter may presage a larger and more debilitating neurologic deficit. The transcranial Doppler, used to track sequentially the larger basal arteries of the brain, specifically the vertebrobasilar arterial system, is an addition to noninvasive diagnostic methods of separating vascular problems from other causes of dizziness.
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Craven, Claudia L., Morrakot Sae-Huang, Chandrashekar Hoskote, Laurence D. Watkins, Ugan Reddy, and Ahmed K. Toma. "Relationship between Brain Tissue Oxygen Tension and Transcranial Doppler Ultrasonography." World Neurosurgery 149 (May 2021): e942-e946. http://dx.doi.org/10.1016/j.wneu.2021.01.070.
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Lindegaard, Karl-Fredrik, Peter Grolimund, Rune Aaslid, and Helge Nornes. "Evaluation of cerebral AVM's using transcranial Doppler ultrasound." Journal of Neurosurgery 65, no. 3 (September 1986): 335–44. http://dx.doi.org/10.3171/jns.1986.65.3.0335.
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✓Blood flow velocities in basal cerebral arteries were recorded noninvasively in 28 patients with cerebral arteriovenous malformations (AVM's) and were correlated with the angiographic findings. In normal arteries remote from the AVM, flow velocities ranged from 44 to 94 cm/sec (median 65 cm/sec) with pulsatility indexes from 0.65 to 1.10 (median 0.87). This is consistent with findings in normal individuals. Arteries feeding the AVM's were identified by the high flow velocities (ranging from 75 to 237 cm/sec, median 124 cm/sec). The pulsatility index ranged from 0.22 to 0.74 (median 0.48). The difference of these results from findings in normal remote arteries was highly significant (p < 0.001). Hyperventilation tests illustrated the hemodynamic difference between an AVM and normal cerebrovascular beds. Flow velocity measurements permitted noninvasive diagnosis of AVM's in 26 of the 28 patients. Furthermore, the identification of individual feeding arteries permitted good definition of the anatomical localization of individual AVM's. Flow velocity measurements combined with computerized tomography scans are useful in the diagnosis of AVM's. With the feeding artery's configuration identified on angiography, flow velocity measurements permit a new insight into the “hemodynamic dimension” of an AVM and its possible effects on adjacent normal brain-tissue perfusion in the individual patient.
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Hertel, Frank, Christof Walter, Martin Bettag, Maria Mörsdorf, R. Loch Macdonald, Gabriele Schackert, and J. Max Findlay. "Perfusion-weighted Magnetic Resonance Imaging in Patients with Vasospasm: A Useful New Tool in the Management of Patients with Subarachnoid Hemorrhage." Neurosurgery 56, no. 1 (January 1, 2005): 28–35. http://dx.doi.org/10.1227/01.neu.0000144866.28101.6d.
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Abstract OBJECTIVE: Cerebral vasospasm (VSP) is one of the most important risk factors for the development of a delayed neurological deficit after subarachnoid hemorrhage (SAH). Perfusion-weighted magnetic resonance imaging (pwMRI) provides the possibility of detecting tissue at risk for infarction. The objective of our study was to evaluate the feasibility and impact of pwMRI in the management of SAH patients. METHODS: From a consecutive series of 180 patients experiencing SAH and treated at our institution over a 3-year period, we identified 20 who underwent pwMRI during their acute illness. For these 20 patients, the results of pwMRI were compared with the results of diffusion-weighted MRI, transcranial Doppler sonography, and neurological examinations performed at the same time and with repeated pwMRI examinations of the same patient at different times. RESULTS: Nineteen of 20 patients showed perfusion changes predominantly in the time maps. Fifteen of 19 patients with changes in pwMRI had a neurological deficit at the same time. In 7 of 15 patients with neurological deterioration, transcranial Doppler sonography showed signs of VSP, whereas all 15 patients showed alterations in pwMRI. The areas of perfusion changes in pwMRI correlated well with the neurological deficits of the patients and were larger than the areas of changed diffusion in diffusion-weighted MRI performed at the same time. There were no clinical complications with regard to the pwMRI examinations. CONCLUSION: pwMRI is safe and helpful in the management of patients with VSP after SAH. The sensitivity of pwMRI is higher than that of transcranial Doppler sonography in the detection of decreased perfusion as a result of VSP. pwMRI can detect tissue at risk before definitive infarction occurs and therefore may lead to a change of therapy in those patients.
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Telman, Gregory, Olga Namestnikov, Efim Kouperberg, Elliot Sprecher, and David Yarnitsky. "Ischemic Middle Cerebral Artery Stroke Missing the Tissue Plasminogen Activator Time Window: Transcranial Doppler Evaluation." Journal of Stroke and Cerebrovascular Diseases 17, no. 6 (November 2008): 366–69. http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2008.04.004.
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Porter, Tyrone M., Christy K. Holland, Jason M. Meunier, and George J. Shaw. "Enhancement of recombinant tissue‐plasminogen activator (rt‐PA) activity with 2‐MHz transcranial Doppler ultrasound." Journal of the Acoustical Society of America 120, no. 5 (November 2006): 3004. http://dx.doi.org/10.1121/1.4787007.
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Musahl, Christian, Hans Henkes, Zsolt Vajda, Jan Coburger, and Nikolai Hopf. "Continuous Local Intra-arterial Nimodipine Administration in Severe Symptomatic Vasospasm After Subarachnoid Hemorrhage." Neurosurgery 68, no. 6 (June 1, 2011): 1541–47. http://dx.doi.org/10.1227/neu.0b013e31820edd46.
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Abstract BACKGROUND: Cerebral vasospasm (CV) is a potentially disastrous consequence of subarachnoid hemorrhage despite medical treatment. Nimodipine is a potent drug for vessel relaxation, but side effects may preclude a sufficient dose. OBJECTIVE: To explore whether continuous local intra-arterial nimodipine administration (CLINA) can reverse vasospasm and prevent delayed ischemic neurological deficit. METHODS: Six consecutive subarachnoid hemorrhage patients (5 women; mean age, 47.2 years) with severe CV despite maximum medical therapy underwent CLINA within 2 hours after the onset of clinical symptoms. After anticoagulation, microcatheters were inserted distally in the concerning supra-aortic vessels. Glyceryl trinitrate injection (2 mg) was followed by CLINA (nimodipine 0.4 mg/h for 70-147 hours). Duration of CLINA was determined by neurological status, transcranial Doppler sonography, and partial tissue oxygen pressure values. RESULTS: In all patients, neurological deficits improved or partial tissue oxygen pressure values returned to normal and transcranial Doppler sonography confirmed a reduced blood flow velocity within 12 hours. Magnetic resonance imaging showed no ischemic lesion caused by CV. Neurological outcome was good (modified Rankin Scale score, 0–2) in 3 patients, whereas 1 patient had a moderate clinical outcome (modified Rankin Scale score, 3–4) and 2 patients had a poor outcome (modified Rankin Scale score, 5) because of the SAH. CONCLUSION: Preliminary data show that CLINA is a straightforward, effective, and safe option for patients with severe CV refractory to medical therapy. Dilation of spastic arteries starts within a few hours and is lasting. Indication for CLINA is peripheral and diffuse CV at any location.
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Gan, Lingli, Xiaoling Yin, Jiating Huang, and Bin Jia. "Transcranial Doppler analysis based on computer and artificial intelligence for acute cerebrovascular disease." Mathematical Biosciences and Engineering 20, no. 2 (2022): 1695–715. http://dx.doi.org/10.3934/mbe.2023077.
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<abstract> <p>Cerebrovascular disease refers to damage to brain tissue caused by impaired intracranial blood circulation. It usually presents clinically as an acute nonfatal event and is characterized by high morbidity, disability, and mortality. Transcranial Doppler (TCD) ultrasonography is a non-invasive method for the diagnosis of cerebrovascular disease that uses the Doppler effect to detect the hemodynamic and physiological parameters of the major intracranial basilar arteries. It can provide important hemodynamic information that cannot be measured by other diagnostic imaging techniques for cerebrovascular disease. And the result parameters of TCD ultrasonography such as blood flow velocity and beat index can reflect the type of cerebrovascular disease and serve as a basis to assist physicians in the treatment of cerebrovascular diseases. Artificial intelligence (AI) is a branch of computer science which is used in a wide range of applications in agriculture, communications, medicine, finance, and other fields. In recent years, there are much research devoted to the application of AI to TCD. The review and summary of related technologies is an important work to promote the development of this field, which can provide an intuitive technical summary for future researchers. In this paper, we first review the development, principles, and applications of TCD ultrasonography and other related knowledge, and briefly introduce the development of AI in the field of medicine and emergency medicine. Finally, we summarize in detail the applications and advantages of AI technology in TCD ultrasonography including the establishment of an examination system combining brain computer interface (BCI) and TCD ultrasonography, the classification and noise cancellation of TCD ultrasonography signals using AI algorithms, and the use of intelligent robots to assist physicians in TCD ultrasonography and discuss the prospects for the development of AI in TCD ultrasonography.</p> </abstract>
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Zivanovic, Zeljko, Andrei Alexandrov, Aleksandar Jesic, and Petar Slankamenac. "Sonothrombolysis: Is the story (t)old or just the beginning." Medical review 67, no. 1-2 (2014): 17–23. http://dx.doi.org/10.2298/mpns1402017z.
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Introduction. Intravenous administration of recombinant tissue plasminogen activator, fastest and widely feasible treatment in acute ischemic stroke induces arterial recanalization, a prerequisite for neurological recovery. The Therapeutic Role of Ultrasound and Potential Mechanism of Sonothrombolysis. Augmentation of recanalization can be achieved safely in combination with diagnostic transcranial Doppler by delivering mechanical pressure waves to the thrombus and exposing more thrombus surface to circulating drug. The addition of microspheres can further improve thrombolytic effect. Clinical Trials. International multicenter CLOTBUST trial showed that acute ischemic stroke patients treated with sonothrombolysis had higher rate of arterial recanalization and dramatic clinical recovery without increasing risk of symptomatic intracranial hemorrhage. A microsphere dose-escalation study called TUCSON showed that rates of recanalization and clinical recovery tended to be higher in target groups compared with controls. Meta-analysis of clinical trials of sonothrombolysis. Cochrane Stroke Group found that sonothrombolysis was likely to reduce death or dependency. A metaanalysis of sonothrombolysis showed that patients who received any form of sonothrombolysis had more than twofold higher likelihood of achieving complete arterial recanalization. Perspectives for sonothrombolysis - Operator-independent device for sonothrombolysis. The collaborative group of the CLOTBUST trial designed multi-transducer assembly to cover conventional windows used for transcranial Doppler examinations. Operatorindependent device can be quickly mounted by medical personnel with no prior experience in ultrasound. Sonothrombolysis for acute ischemic stroke is now tested in a pivotal efficacy multi-national trial called CLOTBUSTER. Conclusion. Ultrasound is a promising tool to enhance systemic thrombolysis.
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Gandee, Richard, and Chad Miller. "Multimodality Monitoring: Toward Improved Outcomes." Seminars in Respiratory and Critical Care Medicine 38, no. 06 (December 2017): 785–92. http://dx.doi.org/10.1055/s-0037-1608774.
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AbstractMultimodality monitoring provides insights into the critically ill brain-injured patient through the assessment of biochemical, physiological, and electrical data that provides insight into a patient's condition and what strategies may be available to limit further damage and improve the odds for recovery. Modalities utilized include evaluation of intracranial pressure along with cerebral perfusion pressure to determine adequate blood flow; continuous electroencephalography to protect the patient from seizures and to identify early functional manifestations of ischemia and toxicity; transcranial Doppler evaluation for bedside review of circulatory adequacy; tissue oxygen monitoring to establish that brain tissue is receiving adequate oxygen from blood flow; and microdialysis to evaluate the metabolic function of the tissue in areas of concern. These monitors provide insights regarding specific aspects of brain tissue and overall brain function in the critically ill patient. Although recommendations continue to evolve for therapeutic targets for each of these modalities, an effective clinician may use each of these modalities to evaluate patients on an individual basis to improve the outcome of each patient, tailoring management to provide the care needed for any unique clinical presentation.
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Alharbi, Meshal, Poppy Turner, Jonathan Ince, Mitsuhiro Oura, Kelechi U. Ebirim, Alanoud Almudayni, Andrea Lecchini-Visintini, Jatinder S. Minhas, and Emma M. L. Chung. "The Effects of Hypocapnia on Brain Tissue Pulsations." Brain Sciences 10, no. 9 (September 6, 2020): 614. http://dx.doi.org/10.3390/brainsci10090614.
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Hypocapnia is known to affect patients with acute stroke and plays a key role in governing cerebral autoregulation. However, the impact of hypocapnia on brain tissue pulsations (BTPs) is relatively unexplored. As BTPs are hypothesised to result from cerebrovascular resistance to the inflow of pulsatile arterial blood, it has also been hypothesised that cerebral autoregulation changes mediated by hypocapnia will alter BTP amplitude. This healthy volunteer study reports measurements of BTPs obtained using transcranial tissue Doppler (TCTD). Thirty participants underwent hyperventilation to induce mild hypocapnia. BTP amplitude, EtCO2, blood pressure, and heart rate were then analysed to explore the impact of hypocapnia on BTP amplitude. Significant changes in BTP amplitude were noted during recovery from hypocapnia, but not during the hyperventilation manoeuvre itself. However, a significant increase in heart rate and pulse pressure and decrease in mean arterial pressure were also observed to accompany hypocapnia, which may have confounded our findings. Whilst further investigation is required, the results of this study provide a starting point for better understanding of the effects of carbon dioxide levels on BTPs. Further research in this area is needed to identify the major physiological drivers of BTPs and quantify their interactions with other aspects of cerebral haemodynamics.
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D'Ausilio, A., L. Maffongelli, E. Bartoli, M. Campanella, E. Ferrari, J. Berry, and L. Fadiga. "Listening to speech recruits specific tongue motor synergies as revealed by transcranial magnetic stimulation and tissue-Doppler ultrasound imaging." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1644 (June 5, 2014): 20130418. http://dx.doi.org/10.1098/rstb.2013.0418.
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The activation of listener's motor system during speech processing was first demonstrated by the enhancement of electromyographic tongue potentials as evoked by single-pulse transcranial magnetic stimulation (TMS) over tongue motor cortex. This technique is, however, technically challenging and enables only a rather coarse measurement of this motor mirroring. Here, we applied TMS to listeners’ tongue motor area in association with ultrasound tissue Doppler imaging to describe fine-grained tongue kinematic synergies evoked by passive listening to speech. Subjects listened to syllables requiring different patterns of dorso-ventral and antero-posterior movements (/ki/, /ko/, /ti/, /to/). Results show that passive listening to speech sounds evokes a pattern of motor synergies mirroring those occurring during speech production. Moreover, mirror motor synergies were more evident in those subjects showing good performances in discriminating speech in noise demonstrating a role of the speech-related mirror system in feed-forward processing the speaker's ongoing motor plan.
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Sun, Li-Li, Wen-Xiong Tang, Min Tian, Lu Zhang, and Zun-Jing Liu. "Clinical Manifestations and Mechanisms of Autoimmune Disease-Related Multiple Cerebral Infarcts." Cell Transplantation 28, no. 8 (May 7, 2019): 1045–52. http://dx.doi.org/10.1177/0963689719846838.
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It is important to investigate the clinical characteristics and identify the stroke mechanisms of patients with autoimmune disease-related stroke, which are necessary for early etiology diagnosis, accurate treatment and preventive strategies. In this article we retrospectively studied eight cases of acute ischemic stroke associated with autoimmune diseases, and without competing conventional stroke etiologies. The characteristics of stroke (clinical and radiological features), the laboratory tests especially serum D-dimer levels (as a marker of hypercoagulable state), and embolic signals on transcranial Doppler were evaluated for all eight patients. High-resolution magnetic resonance imaging (HRMRI), which can help to evaluate vasculitis was performed in four patients. The possible underlying mechanisms of these cases were discussed based on these manifestations. As a result, autoimmune diseases in our study included systemic lupus erythematosus ( n=5), mixed connective tissue disease ( n=1), central nervous system vasculitis ( n=1), and Takayasu arteritis ( n=1). All eight patients presented with acute infarction lesions in ≥2 vascular territories. Most patients presented with numerous small and medium infarction lesions located in the cortical and subcortical areas. Multiple stroke mechanisms were involved in these cases, including hypercoagulability ( n=4), cardiac embolism ( n=1) and vasculitis ( n=3). Embolic signals could be detected on transcranial Doppler in all three stroke mechanisms. In conclusion, our study revealed the characteristics of autoimmune disease-related stroke. For patients with multiple acute cerebral infarcts within non-single arterial territories, autoimmune disease is an important etiology not to be neglected. Multiple stroke mechanisms were involved in these cases.
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Ong, Cheung-Ter, and Rei-Yeuh Chang. "Intravenous Thrombolysis of Occlusion in the Middle Cerebral and Retinal Arteries from Presumed Ventricular Myxoma." Stroke Research and Treatment 2011 (2011): 1–3. http://dx.doi.org/10.4061/2011/735057.
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Background. Although thrombolytic therapy has been shown to be beneficial to stroke patients, the effectiveness of intravenous thrombolysis in ischemic stroke patients with ventricle myxoma is unknown.Case Description. A 22-year-old woman with left hemiplegia was sent to the emergency department at a teaching hospital. The magnetic resonance angiography showed occlusion of the right middle cerebral artery, and the echocardiography showed a mass in the left ventricle. Intravenous recombined tissue plasminogen activator (rt-PA) was administrated, and the postthrombolysis transcranial Doppler exam showed that her right middle cerebral artery was circulative. The patient's condition improved gradually, and no complication was observed up to 16 months of follow-up.Conclusion. Intravenous rt-PA is a reasonable treatment for stroke patients with ventricle myxoma.
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Santibanez, Francisco, Thomas Kierski, Ryan Deruiter, Rebecca Jones, Danai Soulioti, Jake McCall, Hatim Belgharbi, Davis Crews, Paul A. Dayton, and Gianmarco Pinton. "Super-resolution imaging using conventional and non-conventional beamforming." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A53. http://dx.doi.org/10.1121/10.0010633.
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Super-resolution ultrasound surpasses diffraction limits by localizing spatio-temporally separable contrast agents and generates images that significantly exceed the resolution of conventional B-mode imaging methods. However, the ability to detect contrast agents and to separate their signal from the underlying tissue and from sources of image degradation such as phase aberration or reverberation clutter remains a process that is governed by fundamental wave propagation and beamforming. Here, super-resolution imaging and improvements in contrast detection, imaging depth, resolution, and registration accuracy are demonstrated using conventional and non-conventional beamforming methods in 2D and 3D. Three different imaging schemes: (a) single plane-wave, (b) three steered plane-wave compounding, and (c) 256 focused transmits are compared in vivo to quantify the improvements in contrast detection. Wide-beam 3D transcranial super-resolution and power Doppler images through a human and macaque skull are demonstrated using a 1.5 MHz sparse matrix array. These partially and fully focused methods are also demonstrated transcranially in rodents using 2D imaging at 15 MHz and volumetric imaging at 8 MHz. Finally super-harmonic super-resolution imaging approaches are demonstrated for stationary and moving bubbles in murine tumors. These imaging methods extend the capabilities of super-resolution imaging and may improve the clinical translatability of the technique.
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Christou, Ioannis, Andrei V. Alexandrov, W. Scott Burgin, Anne W. Wojner, Robert A. Felberg, Marc Malkoff, and James C. Grotta. "Timing of Recanalization After Tissue Plasminogen Activator Therapy Determined by Transcranial Doppler Correlates With Clinical Recovery From Ischemic Stroke." Stroke 31, no. 8 (August 2000): 1812–16. http://dx.doi.org/10.1161/01.str.31.8.1812.
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Rimini, Daniele, Filippo Molinari, William Liboni, Vincenzo Simonetti, and Marianno Franzini. "The speed of reinfusion affects the vascular system during ozone major autohemotherapy." Ozone Therapy 1, no. 3 (January 18, 2017): 56. http://dx.doi.org/10.4081/ozone.2016.6477.
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Ozone major autohemotherapy (O-MAHT) is a way of ozonetherapy administration consisting of drawing patient’s venous blood, mixing with oxygen/ozone, and reinfusing it into the vein. Some ozone therapists reported side effects during the O-MAHT, but the origin has not been described yet. We investigated the effect of blood drawing velocity during O-MAHT to see its effects on the vascular system and symptomatology. We administered O-MAHT to 11 subjects, and we interleaved fast and slow reinfusions. We monitored cerebral macrocirculation with transcranial Doppler (TCD) and tissue microcirculation with near-infrared spectroscopy (NIRS). Annoying symptoms appeared just during the fast reinfusion periods. NIRS and TCD parameters revealed vasoconstriction during fast reinfusion and improved metabolism during slow reinfusion. Overall, our investigation well discriminated fast from slow reinfusion velocity.
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Stewart, Julian M., Marvin S. Medow, Andrew DelPozzi, Zachary R. Messer, Courtney Terilli, and Christopher E. Schwartz. "Middle cerebral O2 delivery during the modified Oxford maneuver increases with sodium nitroprusside and decreases during phenylephrine." American Journal of Physiology-Heart and Circulatory Physiology 304, no. 11 (June 1, 2013): H1576—H1583. http://dx.doi.org/10.1152/ajpheart.00114.2013.
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The modified Oxford maneuver is the reference standard for assessing arterial baroreflex function. The maneuver comprises a systemic bolus injection of 100 μg sodium nitroprusside (SNP) followed by 150 μg phenylephrine (PE). On the one hand, this results in an increase in oxyhemoglobin and total hemoglobin followed by a decrease within the cerebral sample volume illuminated by near-infrared spectroscopy (NIRS). On the other hand, it produces a decrease in cerebral blood flow velocity (CBFv) within the middle cerebral artery (MCA) during SNP and an increase in CBFv during PE as measured by transcranial Doppler ultrasound. To resolve this apparent discrepancy, we hypothesized that SNP dilates, whereas PE constricts, the MCA. We combined transcranial Doppler ultrasound of the right MCA with NIRS illuminating the right frontal cortex in 12 supine healthy subjects 18–24 yr old. Assuming constant O2 consumption and venous saturation, as estimated by partial venous occlusion plethysmography, we used conservation of mass (continuity) equations to estimate the changes in arterial inflow (ΔQa) and venous outflow (ΔQv) of the NIRS-illuminated area. Oxyhemoglobin and total hemoglobin, respectively, increased by 13.6 ± 1.6 and 15.2 ± 1.4 μmol/kg brain tissue with SNP despite hypotension and decreased by 6 ± 1 and 7 ± 1 μmol/kg with PE despite hypertension. SNP increased ΔQa by 0.36 ± .03 μmol·kg−1·s−1 (21.6 μmol·kg−1·min−1), whereas CBFv decreased from 71 ± 2 to 62 ± 2 cm/s. PE decreased ΔQa by 0.27 ± .2 μmol·kg−1·s−1 (16.2 μmol·kg−1·min−1), whereas CBFv increased to 75 ± 3 cm/s. These results are consistent with dilation of the MCA by SNP and constriction by PE.
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TOTARO, Rocco, Giovanna BARATTELLI, Valentina QUARESIMA, Antonio CAROLEI, and Marco FERRARI. "Evaluation of potential factors affecting the measurement of cerebrovascular reactivity by near-infrared spectroscopy." Clinical Science 95, no. 4 (October 1, 1998): 497–504. http://dx.doi.org/10.1042/cs0950497.
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1.Near-infrared (IR) spectroscopy is based on the relative transparency of skin, skull and brain to the light in the near-IR region (700–1100 ;nm) and on the oxygen-dependent tissue absorption changes of haemoglobin. 2.We evaluated the most relevant factors (reproducibility, venous return, age and sex) that might affect reliability of near-IR spectroscopy to test CO2 cerebrovascular reactivity. 3.Thirty-four healthy volunteers were enrolled in the study. The protocol consisted of a 3-min baseline, a 3-min hypercapnia (5% CO2 in air) and a 2-min recovery. Transcranial Doppler sonography measurements were simultaneously performed. The CO2 reactivity test was repeated on 27 subjects after 1 ;h to assess reproducibility. CO2 reactivity was also evaluated at different body positions (supine, 35° Trendelenburg and 35° reverse Trendelenburg), and over a gradual increase of the inspired CO2. 4.Changes in near-IR spectroscopy and transcranial Doppler sonography parameters were significantly correlated with variations of end-tidal CO2 (P< 0.005). A significant correlation between the reactivity indexes of near-IR spectroscopy parameters and flow velocity was also found (P< 0.01). A high reproducibility was also found for deoxyhaemoglobin (rI = 0.76), oxyhaemoglobin (rI = 0.68) and flow velocity (rI = 0.60) reactivity indexes. No significant differences between the reactivity indexes of different body positions were found (P> 0.05). The reactivity index of oxyhaemoglobin and deoxyhaemoglobin decreased (P< 0.05) and increased (P< 0.01) with age respectively. 5.We found that near-IR spectroscopy is a reliable and reproducible method for the evaluation of cerebrovascular reactivity and might be considered, after appropriate validation, for the assessment of patients with cerebrovascular disease.
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Ikeda, Seiichi, Fumihito Arai, Toshio Fukuda, Makoto Negoro, and Keiko Irie. "An In Vitro Patient-Specific Biological Model of the Cerebral Artery Reproduced with a Membranous Configuration for Simulating Endovascular Intervention." Journal of Robotics and Mechatronics 17, no. 3 (June 20, 2005): 327–34. http://dx.doi.org/10.20965/jrm.2005.p0327.
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We propose an in vitro patient-specific anatomical model of the human cerebral artery and its simulation of endovascular intervention, a potent treatment modality for cerebrovascular diseases. Our proposed model reproduces the 3-dimensional vasculature lumen, using computed tomography (CT) and magnetic resonance (MR) fluoroscopic information, within a thin artery-like membranous configuration having material properties close to arterial tissue. This cerebral arterial model reproduces an exceedingly realistic surgical feel, dynamic vascular deformation and, other important aspects involving endovascular intervention, realizing a highly realistic surgical simulation. We also propose another vasculature model that reproduces the subarachnoid space around the cerebral arteries. This version simulates endovascular intervention realistically. The model is compatible with current major imaging modalities such as CT, MR, and transcranial Doppler (TDC), and should provide effective platforms for applications, such as diagnosis, surgical planning, medical training, hemodynamic analysis and medical system development and evaluation, especially surgical robots.
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Kistka, Heather, Michael C. Dewan, and J. Mocco. "Evidence-Based Cerebral Vasospasm Surveillance." Neurology Research International 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/256713.
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Subarachnoid hemorrhage related to aneurysmal rupture (aSAH) carries significant morbidity and mortality, and its treatment is focused on preventing secondary injury. The most common—and devastating—complication is delayed cerebral ischemia resulting from vasospasm. In this paper, the authors review the various surveillance technologies available to detect cerebral vasospasm in the days following aSAH. First, evidence related to the most common modalities, including transcranial doppler ultrasonography and computed tomography, are reviewed. Continuous electroencephalography and older instruments such as positron emission tomography, xenon-enhanced CT, and single-photon emission computed tomography are also discussed. Invasive strategies including brain tissue oxygen monitoring, microdialysis, thermal diffusion, and jugular bulb oximetry are examined. Lastly, near-infrared spectroscopy, a recent addition to the field, is briefly reviewed. Each surveillance tool carries its own set of advantages and limitations, and the concomitant use of multiple modalities serves to improve diagnostic sensitivity and specificity.
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Blomstrand, Christian, Anne Westerlind, and Christina Jern. "Evidence of a net release of tissue-type plasminogen activator across the human cerebral vasculature." Thrombosis and Haemostasis 91, no. 05 (2004): 1019–25. http://dx.doi.org/10.1160/th03-11-0693.
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SummaryWe have earlier described models for measuring local net release rates of tissue-type plasminogen activator (t-PA) in vivo across skeletal, coronary, pulmonary, and splanchnic vascular beds. Aim of the present study was to investigate whether there is a net release of t-PA across the human cerebral vascular bed and whether an acute regulated release can be induced by sympathoadrenal activation. Fourteen male subjects undergoing elective coronary artery bypass grafting were investigated prior to surgery and during sternotomy-induced sympathoadrenal activation. Blood samples were obtained simultaneously from the radial artery and the jugular bulb. Blood flow velocity in the middle cerebral artery (VMCA) was determined by transcranial Doppler. Cerebral net release of t-PA was calculated as the arterio-venous concentration gradient times VMCA. Prior to surgery there was a significant cerebral net release of t-PA (131 and 42 ng/min for t-PA antigen and activity, respectively). The release was significantly induced by sternotomy (to 271 and 80 ng/min, respectively). No significant cerebral net release of plasminogen activator inhibitor type 1 (PAI-1) was detected throughout the experiment. The results show that there is a basal net release of t-PA across the human cerebral vascular bed and that sympathoadrenal activation induces a local regulated release of t-PA.
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M., Sánchez Lorenzo, and Seoane Pardo R. "The use of ultrasound as a research tool in acupunture: a literature review." Revista Fisioterapia Invasiva / Journal of Invasive Techniques in Physical Therapy 02, no. 02 (December 2019): 082. http://dx.doi.org/10.1055/s-0039-3401864.
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Abstract Background and Aims Ultrasound is a non-invasive test which enables a fast real time exam, which is both dynamic and accessible. In contrast, the mechanisms of functioning of acupuncture have not been completely understood. The aim of this review was to determine the various uses assigned to ultrasound in acupuncture research. Material and Methods A literature search was performed in PubMed, Cochrane Library, PEDro and ScienceDirect databases. Manual searches were performed in the following journals: Evidence-Based Complementary and Alternative Medicine, Acupuncture Medicine, Medical Acupuncture and The Journal of Alternative and Complementary Medicine. The search terms “ultrasonography” and “Acupuncture” were used, related with AND. Research studies in humans were included in which ultrasound was used to assess some aspect of the acupuncture intervention. No time limit was established and the languages were limited to Spanish, English, Galician or Portuguese. The data extraction was performed by two independently blinded evaluators. Results A total of 46 studies were included for the analysis. B Mode is the most used form of imaging, followed by Doppler and elastography. In total, 18 studies performed an analysis of vascular parameters. Doppler was commonly used, with a dominance of transcranial Doppler methods, although B mode was also used to measure the transverse diameter of blood vessels. In 11 studies, B mode was used alone or combined with Doppler to obtain measures of safety, precision, location of target structures and needle position regarding sensitive structures. Seven studies used elastography. Five studies quantified tissue movement and another quantified muscle stiffness using elastography and B mode. A further study also included Doppler for the measurement of blood flow. Six studies evaluated visceral conditions. One study evaluated gastric emptying and the five remaining studies focused on the genitourinary sphere such as the rate of pregnancy, fetal position, prostate characteristics, intrapelvic venous congestion and bladder emptying. From the musculoskeletal point of view, 4 studies were located. Two studies evaluated the thickness parameter of the common extensor tendon of the epicondyle and two layers of connective tissue, respectively. One study concluded that the application of acupuncture can influence the viscoelastic properties of the tendon and one remaining study informed of the positive association between ultrasound as an assessment tool and follow up tool in acupuncture treatments. Conclusions In this field of study, ultrasound has been used to obtain objective outcomes and adopt safety guidelines related to acupuncture procedures.
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Adnyana, I. Made Oka, and Valentina Tjandra Dewi. "CEREBRAL AND SYSTEMIC ENDOTHELIAL DYSFUNCTION IN MIGRAINE: CURRENT KNOWLEDGE AND PERSPECTIVE." Romanian Journal of Neurology 20, no. 2 (June 30, 2021): 138–44. http://dx.doi.org/10.37897/rjn.2021.2.3.
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Migraine still causes a high rate of disability and is reported to increase the risk of cardiovascular and cerebrovascular diseases. Endothelial dysfunction is considered to be one of the underlying mechanisms linking migraine and vascular disorders. Investigation of endothelial function in migraine includes a variety of examinations including biomarkers and ultrasonography-based studies. Several proposed biomarkers for endothelial dysfunction are endothelial progenitor cells (EPCs), von Willebrand factor (vWF), nitric oxide (NO), tissue-type plasminogen activator antigen (tPA antigen), C-reactive protein (CRP), endothelin-1 (ET-1), and vascular endothelial growth factor (VEGF). Brachial flow-mediated dilatation (FMD) is quite commonly used to reflect systemic endothelial dysfunction, while cerebral endothelial function can be assessed using breath holding index (BHI) on transcranial Doppler (TCD). The results of most studies in migraine sufferers indicate that endothelial dysfunction is found locally in the cerebral circulation, especially at the posterior circulation, while evidence for endothelial dysfunction in the systemic circulation remains controversial.
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Mills, Jena N., Vivek Mehta, Jonathan Russin, Arun P. Amar, Anandh Rajamohan, and William J. Mack. "Advanced Imaging Modalities in the Detection of Cerebral Vasospasm." Neurology Research International 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/415960.
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The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT,133Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.
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Tasneem, Nudrat, Edgar A. Samaniego, Connie Pieper, Enrique C. Leira, Harold P. Adams, David Hasan, and Santiago Ortega-Gutierrez. "Brain Multimodality Monitoring: A New Tool in Neurocritical Care of Comatose Patients." Critical Care Research and Practice 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6097265.
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Neurocritical care patients are at risk of developing secondary brain injury from inflammation, ischemia, and edema that follows the primary insult. Recognizing clinical deterioration due to secondary injury is frequently challenging in comatose patients. Multimodality monitoring (MMM) encompasses various tools to monitor cerebral metabolism, perfusion, and oxygenation aimed at detecting these changes to help modify therapies before irreversible injury sets in. These tools include intracranial pressure (ICP) monitors, transcranial Doppler (TCD), Hemedex™ (thermal diffusion probe used to measure regional cerebral blood flow), microdialysis catheter (used to measure cerebral metabolism), Licox™ (probe used to measure regional brain tissue oxygen tension), and continuous electroencephalography. Although further research is needed to demonstrate their impact on improving clinical outcomes, their contribution to illuminate the black box of the brain in comatose patients is indisputable. In this review, we further elaborate on commonly used MMM parameters, tools used to measure them, and the indications for monitoring per current consensus guidelines.
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Ghosh, Arnab, David Highton, Christina Kolyva, Ilias Tachtsidis, Clare E. Elwell, and Martin Smith. "Hyperoxia results in increased aerobic metabolism following acute brain injury." Journal of Cerebral Blood Flow & Metabolism 37, no. 8 (January 1, 2016): 2910–20. http://dx.doi.org/10.1177/0271678x16679171.
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Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24–72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy. Increased inspired oxygen resulted in increased pbrO2 [ΔpbrO2 30.9 mmHg p < 0.001], reduced LPR [ΔLPR −3.07 p = 0.015], and increased cytochrome c oxidase (CCO) oxidation (Δ[oxCCO] + 0.32 µM p < 0.001) which persisted on return-to-baseline (Δ[oxCCO] + 0.22 µM, p < 0.01), accompanied by a 7.5% increase in estimated cerebral metabolic rate for oxygen ( p = 0.038). Our results are consistent with an improvement in cellular redox state, suggesting oxygen-limited metabolism above recognised ischaemic pbrO2 thresholds. Diffusion limitation or mitochondrial inhibition might explain these findings. Further investigation is warranted to establish optimal oxygenation to sustain aerobic metabolism after acute brain injury.
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Greco, Frédéric. "Technical Assessment of Ultrasonic Cerebral Tomosphygmography and New Scientific Evaluation of Its Clinical Interest for the Diagnosis of Electrohypersensitivity and Multiple Chemical Sensitivity." Diagnostics 10, no. 6 (June 24, 2020): 427. http://dx.doi.org/10.3390/diagnostics10060427.
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Ultrasonic cerebral tomosphygmography (UCTS), also known as “encephaloscan”, is an ultrasound-based pulsatile echoencephalography for both functional and anatomical brain imaging investigations. Compared to classical imaging, UCTS makes it possible to locate precisely the spontaneous brain tissue pulsations that occur naturally in temporal lobes. Scientific publications have recently validated the scientific interest of UCTS technique but clinical use and industrial development of this ancient brain imaging technique has been stopped notably in France, not for scientific or technical reasons but due to a lack of financing support. UCTS should be fundamentally distinguished from transcranial Doppler ultrasonography (TDU), which, although it also uses pulsed ultrasounds, aims at studying the velocity of blood flow (hemodynamics) in the cerebral arteries by using Doppler effect, especially in the middle cerebral artery of both hemispheres. Instead, UCTS has the technical advantage of measuring and locating spontaneous brain tissue pulsations in temporal lobes. Recent scientific work has shown the possibility to make an objective diagnosis of electrohypersensitivity (EHS) and multiple chemical sensitivity (MCS) by using UCTS, in conjunction with TDU investigation and the detection of several biomarkers in the peripheral blood and urine of the patients. In this paper, we independently confirm the clinical interest of using UCTS for the diagnosis of EHS and MCS. Moreover, it has been shown that repetitive use of UCTS in EHS and/or MCS patients can contribute to the objective assessment of their therapeutic follow-up. Since classical CT scan and MRI are usually not contributive for the diagnosis and are poorly tolerated by these patients, UCTS should therefore be considered as one of the best imaging technique to be used for the diagnosis of these new disorders and the follow-up of patients.
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Jia, Zaishen, Yichao Teng, Yuan Liu, Hong Wang, Yue Li, and Xiaotong Hou. "Influence of high-flow modified ultrafiltration on brain oxygenation and perfusion during surgery for children with ventricular septal defects: a pilot study." Perfusion 33, no. 3 (October 6, 2017): 203–8. http://dx.doi.org/10.1177/0267659117736120.
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Background: Modified ultrafiltration (MUF) can be performed in infants with ventricular septal defects (VSDs) after cardiopulmonary bypass (CPB) to reduce haemodilution and its potential adverse effects. High-flow MUF might reduce ultrafiltration duration and hasten the necessary correction of haemodilution during CPB. However, its influence on brain oxygenation remains controversial. Objective: This non-randomized, prospective, pilot study aimed to investigate the influence of high-flow MUF on brain oxygenation in infants with VSDs. Methods: High-flow MUF (≥20 mL/kg/min) was performed in twenty infants. Brain oxygen saturation (rSO2) and tissue haemoglobin index (tHI) were non-invasively and continuously measured intraoperatively using near-infrared spectroscopy (NIRS). Transcranial Doppler non-invasively detected the mean flow velocity of the middle cerebral artery (Vmean). Results: rSO2 increased significantly during MUF, as did tHI, Vmean, mean arterial pressure and haematocrit (all p<0.05). No correlation was found between changes in rSO2 and changes in other parameters (all p≥0.05). Conclusion: In infants with ventricular septal defects managed with CPB during VSDs repair, high-flow MUF did not reduce brain oxygenation.
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Bor-Seng-Shu, Edson, Ricardo De Carvalho Nogueira, Eberval G. Figueiredo, Eli Faria Evaristo, Adriana Bastos Conforto, and Manoel Jacobsen Teixeira. "Sonothrombolysis for acute ischemic stroke: a systematic review of randomized controlled trials." Neurosurgical Focus 32, no. 1 (January 2012): E5. http://dx.doi.org/10.3171/2011.10.focus11251.
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Object Sonothrombolysis has recently been considered an emerging modality for the treatment of stroke. The purpose of the present paper was to review randomized clinical studies concerning the effects of sonothrombolysis associated with tissue plasminogen activator (tPA) on acute ischemic stroke. Methods Systematic searches for literature published between January 1996 and July 2011 were performed for studies regarding sonothrombolysis combined with tPA for acute ischemic stroke. Only randomized controlled trials were included. Data extraction was based on ultrasound variables, patient characteristics, and outcome variables (rate of intracranial hemorrhages and arterial recanalization). Results Four trials were included in this study; 2 trials evaluated the effect of transcranial Doppler (TCD) ultrasonography on sonothrombolysis, and 2 addressed transcranial color-coded duplex (TCCD) ultrasonography. The frequency of ultrasound waves varied from 1.8 to 2 MHz. The duration of thrombus exposure to ultrasound energy ranged from 60 to 120 minutes. Sample sizes were small, recanalization was evaluated at different time points (60 and 120 minutes), and inclusion criteria were heterogeneous. Sonothrombolysis combined with tPA did not lead to an increase in symptomatic intracranial hemorrhagic complications. Two studies demonstrated that patients treated with ultrasound combined with tPA had statistically significant higher rates of recanalization than patients treated with tPA alone. Conclusions Despite the heterogeneity and the limitations of the reviewed studies, there is evidence that sonothrombolysis associated with tPA is a safe procedure and results in an increased rate of recanalization in the setting of acute ischemic stroke when wave frequencies and energy intensities of diagnostic ultrasound systems are used.
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Tomoto, Tsubasa, Jun Sugawara, Yoshie Nogami, Kazutaka Aonuma, and Seiji Maeda. "The influence of central arterial compliance on cerebrovascular hemodynamics: insights from endurance training intervention." Journal of Applied Physiology 119, no. 5 (September 1, 2015): 445–51. http://dx.doi.org/10.1152/japplphysiol.00129.2015.
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Normally, central elastic arteries (e.g., aorta and common carotid artery) effectively buffer cardiac pulsation-induced flow/pressure fluctuations. With advancing age, arterial stiffening deteriorates this function and produces the greater cerebral hemodynamic pulsatility that impacts vulnerable brain tissue. It is well known that the buffering function of the central artery is improved by regular aerobic exercise, but the influence of endurance training on the pulsatile component of cerebral hemodynamics remains poorly understood. To characterize the functional role of the central artery at the heart-brain hemodynamic connection comprehensively, we assessed relations among the endurance training-induced changes in the left ventricle (LV), carotid arterial compliance, and cerebral hemodynamics. Thirteen collegiate tennis players (20 ± 1 yr) underwent a 16-wk endurance training intervention designed for improving cardiovascular function. Expectedly, maximal oxygen uptake (V̇o2peak), LV ejection velocity (via Doppler ultrasound), and the maximal rate of pressure increase of estimated aortic pressure waveform (via general transfer function) improved after the training intervention, whereas middle cerebral arterial (MCA) hemodynamics (via transcranial Doppler), such as mean and pulsatile flow velocities, remained unchanged. Carotid arterial compliance (via ultrasound and applanation tonometry) increased after the training intervention, and a larger increase in carotid arterial compliance was significantly associated with the greater attenuations of pulsatile MCA velocity ( r = −0.621) normalized by mean MCA velocity. These results suggest that the training-induced improvement of carotid artery Windkessel function might offset the expected increase in the pulsatile component of cerebral perfusion induced by the enhanced LV systolic function.
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Ribo, Marc, Carlos A. Molina, Alex Rovira, Manuel Quintana, Pilar Delgado, Joan Montaner, Elisenda Grivé, Juan F. Arenillas, and José Álvarez-Sabín. "Safety and Efficacy of Intravenous Tissue Plasminogen Activator Stroke Treatment in the 3- to 6-Hour Window Using Multimodal Transcranial Doppler/MRI Selection Protocol." Stroke 36, no. 3 (March 2005): 602–6. http://dx.doi.org/10.1161/01.str.0000155737.43566.ad.
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Demchuk, Andrew M., W. Scott Burgin, Ioannis Christou, Robert A. Felberg, Philip A. Barber, Michael D. Hill, and Andrei V. Alexandrov. "Thrombolysis in Brain Ischemia (TIBI) Transcranial Doppler Flow Grades Predict Clinical Severity, Early Recovery, and Mortality in Patients Treated With Intravenous Tissue Plasminogen Activator." Stroke 32, no. 1 (January 2001): 89–93. http://dx.doi.org/10.1161/01.str.32.1.89.
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Baker, Wesley B., Ashwin B. Parthasarathy, Kimberly P. Gannon, Venkaiah C. Kavuri, David R. Busch, Kenneth Abramson, Lian He, et al. "Noninvasive optical monitoring of critical closing pressure and arteriole compliance in human subjects." Journal of Cerebral Blood Flow & Metabolism 37, no. 8 (May 25, 2017): 2691–705. http://dx.doi.org/10.1177/0271678x17709166.
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The critical closing pressure ( CrCP) of the cerebral circulation depends on both tissue intracranial pressure and vasomotor tone. CrCP defines the arterial blood pressure ( ABP) at which cerebral blood flow approaches zero, and their difference ( ABP − CrCP) is an accurate estimate of cerebral perfusion pressure. Here we demonstrate a novel non-invasive technique for continuous monitoring of CrCP at the bedside. The methodology combines optical diffuse correlation spectroscopy (DCS) measurements of pulsatile cerebral blood flow in arterioles with concurrent ABP data during the cardiac cycle. Together, the two waveforms permit calculation of CrCP via the two-compartment Windkessel model for flow in the cerebral arterioles. Measurements of CrCP by optics (DCS) and transcranial Doppler ultrasound (TCD) were carried out in 18 healthy adults; they demonstrated good agreement (R = 0.66, slope = 1.14 ± 0.23) with means of 11.1 ± 5.0 and 13.0 ± 7.5 mmHg, respectively. Additionally, a potentially useful and rarely measured arteriole compliance parameter was derived from the phase difference between ABP and DCS arteriole blood flow waveforms. The measurements provide evidence that DCS signals originate predominantly from arteriole blood flow and are well suited for long-term continuous monitoring of CrCP and assessment of arteriole compliance in the clinic.
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Parthasarathy, Ashwin B., Kimberly P. Gannon, Wesley B. Baker, Christopher G. Favilla, Ramani Balu, Scott E. Kasner, Arjun G. Yodh, John A. Detre, and Michael T. Mullen. "Dynamic autoregulation of cerebral blood flow measured non-invasively with fast diffuse correlation spectroscopy." Journal of Cerebral Blood Flow & Metabolism 38, no. 2 (December 12, 2017): 230–40. http://dx.doi.org/10.1177/0271678x17747833.
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Cerebral autoregulation (CA) maintains cerebral blood flow (CBF) in the presence of systemic blood pressure changes. Brain injury can cause loss of CA and resulting dysregulation of CBF, and the degree of CA impairment is a functional indicator of cerebral tissue health. Here, we demonstrate a new approach to noninvasively estimate cerebral autoregulation in healthy adult volunteers. The approach employs pulsatile CBF measurements obtained using high-speed diffuse correlation spectroscopy (DCS). Rapid thigh-cuff deflation initiates a chain of responses that permits estimation of rates of dynamic autoregulation in the cerebral microvasculature. The regulation rate estimated with DCS in the microvasculature (median: 0.26 s−1, inter quartile range: 0.19 s−1) agrees well (R = 0.81, slope = 0.9) with regulation rates measured by transcranial Doppler ultrasound (TCD) in the proximal vasculature (median: 0.28 s−1, inter quartile range: 0.10 s−1). We also obtained an index of systemic autoregulation in concurrently measured scalp microvasculature. Systemic autoregulation begins later than cerebral autoregulation and exhibited a different rate (0.55 s−1, inter quartile range: 0.72 s−1). Our work demonstrates the potential of diffuse correlation spectroscopy for bedside monitoring of cerebral autoregulation in the microvasculature of patients with brain injury.
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Uzuner, Nevzat, Özcan Özdemir, and Gülnur Tekgöl Uzuner. "Relationship between Pulsatility Index and Clinical Course of Acute Ischemic Stroke after Thrombolytic Treatment." BioMed Research International 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/265171.
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Background. The relationship between the arterial recanalization after intravenous recombinant tissue plasminogen activator (rtPA) and outcomes is still uncertain. The aim of our study was to evaluate whether there is an association between the pulsatility indexes (PI) of the middle cerebral artery (MCA) measured by transcranial Doppler (TCD) after iv rtPA treatment and short- and long-term outcomes in ischemic stroke patients.Methods. Forty-eight patients with acute ischemia in the MCA territory who achieved complete recanalization after the administration of intravenous thrombolytic treatment were included in the study. The TCD was applied to patients after the iv rtPA treatment. Clinical and functional outcomes were assessed by National Institutes of Health Stroke Scale (NIHSS) scores and modified Rankin Scores (mRS), respectively.Results. Significant positive correlations were found between the PI value and NIHSS score at 24 hours, NIHSS score at 3 months, and mRS at 3 months ( for all). The cut-off value for PI in predicting a favorable prognosis and a good prognosis might be less than or equal to 1.1 and less than or equal to 1.4, respectively.Conclusions. PI may play a role in predicting the functional and clinical outcome after thrombolytic therapy in acute ischemic stroke patients.
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Ramakrishna, Rohan, Laligam N. Sekhar, Dinesh Ramanathan, Nancy Temkin, Danial Hallam, Basavaraj V. Ghodke, and Louis J. Kim. "Intraventricular Tissue Plasminogen Activator for the Prevention of Vasospasm and Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage." Neurosurgery 67, no. 1 (July 1, 2010): 110–17. http://dx.doi.org/10.1227/01.neu.0000370920.44359.91.
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Abstract BACKGROUND The sequelae of aneurysmal subarachnoid hemorrhage (SAH) include vasospasm and hydrocephalus. OBJECTIVE To assess whether intraventricular tissue plasminogen activator (tPA) results in less vasospasm, fewer angioplasties, or fewer cerebrospinal fluid shunting procedures. METHODS 41 patients (tPA group, Hunt and Hess 3, 4, 5) from 2007 to 2008 received intraventricular tPA and lumbar drainage for a minimum of 5 days (range 5–7 days) and were compared to a matched group of 35 patients from 2006 to 2007 (Control, HH 3, 4, 5). Statistical comparison was done by t test analysis or Fisher exact tests and data are expressed as average ± standard error of the mean. RESULTS There were no significant differences in demographic data, although the tPA group had a trend toward more surgical patients. The tPA group of patients had a significantly higher modified Fisher grade than controls (P < .001) and had a significantly better Hunt and Hess grade than controls (P < .03). The angioplasty rate was significantly lower among the tPA patients (15.0% ± 5.6) than controls (40.0% ± 8.5, P = .019). The number of days spent in severe vasospasm normalized over the 14-day monitoring period by transcranial Doppler was significantly lower in the tPA group (0.09 ± 0.02) than controls (0.17 ± 0.03). The shunt rate was significantly lower among tPA patients (17.5% ± 6.0) than controls (42.8% ± 8.6). There were 2 clinically silent tract hemorrhages in the tPA group (4.8%). CONCLUSION Intraventricular tPA is a safe and effective treatment for reducing both angioplasty and shunting rates in patients with SAH H&H Grades 3 to 5. A randomized trial is indicated.
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Hoelper, Bernd Manfred, Erich Hofmann, Roland Sporleder, Florian Soldner, and Robert Behr. "Transluminal Balloon Angioplasty Improves Brain Tissue Oxygenation and Metabolism in Severe Vasospasm after Aneurysmal Subarachnoid Hemorrhage: Case Report." Neurosurgery 52, no. 4 (April 1, 2003): 970–76. http://dx.doi.org/10.1227/01.neu.0000053033.98317.a3.
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Abstract OBJECTIVE AND IMPORTANCE The effect of transluminal balloon angioplasty on cerebral biochemical monitoring during treatment of severe cerebral vasospasm after subarachnoid hemorrhage (SAH) was investigated. CLINICAL PRESENTATION In a 36-year-old man, an anterior communicating artery aneurysm caused an SAH (Hunt and Hess Grade IV, Fisher Grade III). After clipping, intraparenchymal monitoring (intracranial pressure, brain tissue oxygen tension [PtiO2], and microdialysis sampling of extracellular glucose, lactate, pyruvate, and glutamate) was initiated. Flow velocities obtained by transcranial Doppler sonography increased in the internal carotid artery (ICA)/middle cerebral artery bilaterally. INTERVENTION After a decrease of PtiO2to less than 2 mm Hg and an increase of the lactate-to-pyruvate ratio to 44 in the territorial region of the left ICA, angiography demonstrated a 70 to 80% stenosis of the left ICA, which was dilated by a temporary occlusion balloon. This maneuver normalized the ICA diameter, PtiO2increased immediately from 1.5 to 40 mm Hg, the lactate-to-pyruvate ratio decreased from 44 to 30, and extracellular glucose increased from 0.4 to 0.9 mmol/L. No major changes in glutamate or intracranial pressure were seen. In the clinical follow-up, the patient showed a good recovery 6 months after SAH. CONCLUSION Transluminal balloon angioplasty led to a continuous and effective resolution of cerebral vasospasm observed by sustained, improved cerebral biochemical parameters. Both PtiO2and lactate-to-pyruvate ratio might provide an early diagnosis of severe cerebral vasospasm after SAH and continuous surveillance of threatened tissue regions after transluminal balloon angioplasty.
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Chang, Nathan, and Lindsey Rasmussen. "Exploring Trends in Neuromonitoring Use in a General Pediatric ICU: The Need for Standardized Guidance." Children 9, no. 7 (June 22, 2022): 934. http://dx.doi.org/10.3390/children9070934.
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Neuromonitoring has become more standardized in adult neurocritical care, but the utility of different neuromonitoring modalities in children remains debated. We aimed to describe the use of neuromonitoring in critically ill children with and without primary neurological diseases. We conducted a retrospective review of patients admitted to a 32-bed, non-cardiac PICU during a 12-month period. Neuro-imaging, electroencephalogram (EEG), cerebral oximetry (NIRS), automated pupillometry, transcranial doppler (TCD), intracranial pressure (ICP) monitoring, brain tissue oxygenation (PbtO2), primary diagnosis, and outcome were extracted. Neuromonitoring use by primary diagnosis and associations with outcome were observed. Of 1946 patients, 420 received neuro-imaging or neuromonitoring. Primary non-neurological diagnoses most frequently receiving neuromonitoring were respiratory, hematologic/oncologic, gastrointestinal/liver, and infectious/inflammatory. The most frequently used technologies among non-neurological diagnoses were neuro-imaging, EEG, pupillometry, and NIRS. In the multivariate analysis, pupillometry use was associated with mortality, and EEG, NIRS, and neuro-imaging use were associated with disability. Frequencies of TCD and PbtO2 use were too small for analysis. Neuromonitoring is prevalent among various diagnoses in the PICU, without clear benefit on outcomes when used in an ad hoc fashion. We need standard guidance around who, when, and how neuromonitoring should be applied to improve the care of critically ill children.
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Ott, Stephanie, Sheila Jedlicka, Stefan Wolf, Mozes Peter, Christine Pudenz, Patrick Merker, Ludwig Schürer, and Christianto Benjamin Lumenta. "Continuous Selective Intra-Arterial Application of Nimodipine in Refractory Cerebral Vasospasm due to Aneurysmal Subarachnoid Hemorrhage." BioMed Research International 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/970741.
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Background. Cerebral vasospasm is one of the leading courses for disability in aneurysmal subarachnoid hemorrhage. Effective treatment of vasospasm is therefore one of the main priorities for these patients. We report about a case series of continuous intra-arterial infusion of the calcium channel antagonist nimodipine for 1–5 days on the intensive care unit.Methods. In thirty patients with aneurysmal subarachnoid hemorrhage and refractory vasospasm continuous infusion of nimodipine was started on the neurosurgical intensive care unit. The effect of nimodipine on brain perfusion, cerebral blood flow, brain tissue oxygenation, and blood flow velocity in cerebral arteries was monitored.Results. Based on Hunt & Hess grades on admission, 83% survived in a good clinical condition and 23% recovered without an apparent neurological deficit. Persistent ischemic areas were seen in 100% of patients with GOS 1–3 and in 69% of GOS 4-5 patients. Regional cerebral blood flow and computed tomography perfusion scanning showed adequate correlation with nimodipine application and angiographic vasospasm. Transcranial Doppler turned out to be unreliable with interexaminer variance and failure of detecting vasospasm or missing the improvement.Conclusion. Local continuous intra-arterial nimodipine treatment for refractory cerebral vasospasm after aSAH can be recommended as a low-risk treatment in addition to established endovascular therapies.
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Zhang, Peizhen, Guoyuan Huang, and Xiangrong Shi. "Cerebral vasoreactivity during hypercapnia is reset by augmented sympathetic influence." Journal of Applied Physiology 110, no. 2 (February 2011): 352–58. http://dx.doi.org/10.1152/japplphysiol.00802.2010.
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Sympathetic nerve activity influences cerebral blood flow, but it is unknown whether augmented sympathetic nerve activity resets cerebral vasoreactivity to hypercapnia. This study tested the hypothesis that cerebral vasodilation during hypercapnia is restrained by lower-body negative pressure (LBNP)-stimulated sympathoexcitation. Cerebral hemodynamic responses were assessed in nine healthy volunteers [age 25 yr (SD 3)] during rebreathing-induced increases in partial pressure of end-tidal CO2 (PetCO2) at rest and during LBNP. Cerebral hemodynamic responses were determined by changes in flow velocity of middle cerebral artery (MCAV) using transcranial Doppler sonography and in regional cerebral tissue oxygenation (ScO2) using near-infrared spectroscopy. PetCO2 values during rebreathing were similarly increased from 41.9 to 56.5 mmHg at rest and from 40.7 to 56.0 mmHg during LBNP of −15 Torr. However, the rates of increases in MCAV and in ScO2 per unit increase in PetCO2 (i.e., the slopes of MCAV/PetCO2 and ScO2/PetCO2) were significantly ( P ≤0.05) decreased from 2.62 ± 0.16 cm·s−1·mmHg−1 and 0.89 ± 0.10%/mmHg at rest to 1.68 ± 0.18 cm·s−1·mmHg−1 and 0.63 ± 0.07%/mmHg during LBNP. In conclusion, the sensitivity of cerebral vasoreactivity to hypercapnia, in terms of the rate of increases in MCAV and in ScO2, is diminished by LBNP-stimulated sympathoexcitation.
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Del Pozzi, Andrew T., Akash Pandey, Marvin S. Medow, Zachary R. Messer, and Julian M. Stewart. "Blunted cerebral blood flow velocity in response to a nitric oxide donor in postural tachycardia syndrome." American Journal of Physiology-Heart and Circulatory Physiology 307, no. 3 (August 1, 2014): H397—H404. http://dx.doi.org/10.1152/ajpheart.00194.2014.
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Cognitive deficits are characteristic of postural tachycardia syndrome (POTS). Intact nitrergic nitric oxide (NO) is important to cerebral blood flow (CBF) regulation, neurovascular coupling, and cognitive efficacy. POTS patients often experience defective NO-mediated vasodilation caused by oxidative stress. We have previously shown dilation of the middle cerebral artery in response to a bolus administration of the NO donor sodium nitroprusside (SNP) in healthy volunteers. In the present study, we hypothesized a blunted middle cerebral artery response to SNP in POTS. We used combined transcranial Doppler-ultrasound to measure CBF velocity and near-infrared spectroscopy to measure cerebral hemoglobin oxygenation while subjects were in the supine position. The responses of 17 POTS patients were compared with 12 healthy control subjects (age: 14–28 yr). CBF velocity in POTS patients and control subjects were not different at baseline (75 ± 3 vs. 71 ± 2 cm/s, P = 0.31) and decreased to a lesser degree with SNP in POTS patients (to 71 ± 3 vs. 62 ± 2 cm/s, P = 0.02). Changes in total and oxygenated hemoglobin (8.83 ± 0.45 and 8.13 ± 0.48 μmol/kg tissue) were markedly reduced in POTS patients compared with control subjects (14.2 ± 1.4 and 13.6 ± 1.6 μmol/kg tissue), primarily due to increased venous efflux. The data indicate reduced cerebral oxygenation, blunting of cerebral arterial vasodilation, and heightened cerebral venodilation. We conclude, based on the present study outcomes, that decreased bioavailability of NO is apparent in the vascular beds, resulting in a downregulation of NO receptor sites, ultimately leading to blunted responses to exogenous NO.
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Bernaudin, Francoise, Suzanne Verlhac, Lena COIC, Emmanuelle Lesprit, Pierre Brugieres, and Philippe Reinert. "Long Term Follow-Up of Pediatric SCD Patients with Abnormal High Velocities on Transcranial Doppler: Monocenter Experience in Creteil, France." Blood 104, no. 11 (November 16, 2004): 1656. http://dx.doi.org/10.1182/blood.v104.11.1656.1656.
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Abstract Abnormal high velocities are predictive of high stroke risk which can be significantly reduced by transfusion program (Adams and al). They are related to stenosis, severe anemia or tissue hypoxia. We hypothesized that high velocities observed in patients with normal MRA and normalized on transfusion program (TP), were anemia related and could be safely decreased with hydroxyurea (HU)-therapy. Patients and Methods: since 1992, 291 pediatric SCD patients (235 SS, 40 SC, 3 Sb0, 11 Sb+) were systematically explored once a year by TCD. The newborn screened cohort (n=149) had the first TCD exploration between 12 and 18 months age. TCD was performed with a real-time imaging unit, using a 2 MHz sector transducer with color Doppler capabilities. When abnormal high velocities (defined as mean maximum velocities > 200 cm/sec in MCA, ACA or ICA) were observed, TCD was controlled and the patient treated with TP and cerebral imaging (MRI/MRA) was performed within 3 months. In patients with severe stenosis, TP was pursued or transplantation performed. In patients with normal MRA and transfusion-normalized velocities, a progressive switch towards HU therapy was applied and TCD controlled once a trimester. Results: among the stroke-free patients (n=281), abn. high velocities were detected in 25 patients (all SS:11% of incidence in SS patients). In the newborn screened population, velocities became abnormal in 10 patients at the median age of 5.7 years (range 1.4 – 12.5 y). The first MRI/MRA (n=24/25) performed in the 3 months following the detection of high velocities showed MRI/silent infarcts in 9/24 (38%): only 1/11 among the newborn screened cohort had silent infarcts in contrast with 8/13 older patients secondary referred in our center. MRA detected severe vascular abnormalities in 10 and mild in 3 patients. Mean velocities (2.69 m/sec) were significantly higher (p=0.002) in the 7 patients with abn. MRI and MRA than in the 10 patients (2.11m/sec) who had normal MRI and MRA. One stroke occurred in a very young 1.6 y old girl just before the second TCD evaluation (first abn. TCD had been observed at 1.5 y) and before the beginning of the TP. Long-term outcome: no stroke was observed following the initiation of the TP. With a median follow-up of 4.4 years (0.5 to 11.4 y.), velocities remained abnormal in 11/25 patients: 7 of them had abnormal MRA and among the 4 patients with normal MRA at first exploration MRA became abnormal in 2 cases showing that abnormal TCD can precede the occurrence of cerebral vasculopathy. TP was maintained in 7 patients and safely stopped in 4 patients transplanted with genoidentical donor. Velocities normalization (defined as < 170 cm/sec) was observed in 13/25 patients in a median delay of 0.75 years (0.25 – 2.3 years). TP was stopped in 10 patients with normal MRA and therapy was switched towards HU in 7 patients with abstention in 3. However, abnormal TCD relapsed in 4 patients who were again placed on TP. Conclusion: abnormal high velocities concerned 11% of SS patients and were predictive of MRA and MRI lesions occurrence. TP was efficient to prevent the stroke risk and normalized velocities in about 50% of patients but relapses were observed in 4/7 patients following TP stop and HU switch. Only few patients with high velocities history did not develop cerebral vasculopathy. Also, early TCD allows a selection of very high risk patients justifying the research of suitable donors.
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Dostanic, M. M., M. M. Stosic, B. D. Milakovic, B. V. Baljozovic, I. B. Jovanovic, Z. Kojic, D. M. Marinkovic, D. J. Markovic, and I. S. Milic. "New trends in neuromonitoring patients with aneurysmal subarachnoid haemorrhage." Acta chirurgica Iugoslavica 55, no. 2 (2008): 69–74. http://dx.doi.org/10.2298/aci0802069d.
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Neurointensive care of patients with subarachnoid haemorrhage is based on the theory that clinical outcome is the consequence of the primary haemorrhage and a number of secondary insults in the acute post haemorrhage period. Several neuromonitoring techniques have been introduced or accomplished into clinical practice in the last decade with the purpose of monitoring different but related aspects of brain physiology, such as cerebral blood flow (CBF), pressure within the cranial cavity, metabolism, and oxygenation. The aim of these techniques is to obtain information that can improve knowledge on brain pathophysiology, and especially to detect secondary insults which may cause permanent neurological damage if undetected and untreated in "real time", at the time when they can still be managed. These techniques include intracranial pressure (ICP) measurements, jugular venous oxygen saturation, near-infrared spectroscopy, brain tissue monitoring, and transcranial Doppler. The available devices are limited because they measure a part of complex process indirectly. Expense, technical difficulties, invasiveness, limited spatial or temporal resolution and the lack of sensitivity add to the limitation of any individual monitor. These problems have been partially addressed by the combination of several monitors known as multimodality monitoring. In this review, we describe the most common neuromonitoring methods in patients with subarachnoidal hemorrhage that can assess nervous system function, cerebral haemodynamics and cerebral oxygenation.
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Rupp, Thomas, François Esteve, Pierre Bouzat, Carsten Lundby, Stéphane Perrey, Patrick Levy, Paul Robach, and Samuel Verges. "Cerebral Hemodynamic and Ventilatory Responses to Hypoxia, Hypercapnia, and Hypocapnia during 5 Days at 4,350 m." Journal of Cerebral Blood Flow & Metabolism 34, no. 1 (September 25, 2013): 52–60. http://dx.doi.org/10.1038/jcbfm.2013.167.
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This study investigated the changes in cerebral near-infrared spectroscopy (NIRS) signals, cerebrovascular and ventilatory responses to hypoxia and CO2 during altitude exposure. At sea level (SL), after 24 hours and 5 days at 4,350 m, 11 healthy subjects were exposed to normoxia, isocapnic hypoxia, hypercapnia, and hypocapnia. The following parameters were measured: prefrontal tissue oxygenation index (TOI), oxy- (HbO2), deoxy- and total hemoglobin (HbTot) concentrations with NIRS, blood velocity in the middle cerebral artery (MCAv) with transcranial Doppler and ventilation. Smaller prefrontal deoxygenation and larger ΔHbTot in response to hypoxia were observed at altitude compared with SL (day 5: ΔHbO2−0.6±1.1 versus −1.8±1.3 μmol/cmper mm Hg and ΔHbTot 1.4±1.3 versus 0.7±1.1 μmol/cm per mm Hg). The hypoxic MCAv and ventilatory responses were enhanced at altitude. Prefrontal oxygenation increased less in response to hypercapnia at altitude compared with SL (day 5: ΔTOI 0.3±0.2 versus 0.5±0.3% mm Hg). The hypercapnic MCAv and ventilatory responses were decreased and increased, respectively, at altitude. Hemodynamic responses to hypocapnia did not change at altitude. Short-term altitude exposure improves cerebral oxygenation in response to hypoxia but decreases it during hypercapnia. Although these changes may be relevant for conditions such as exercise or sleep at altitude, they were not associated with symptoms of acute mountain sickness.
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Belpomme, Dominique, and Philippe Irigaray. "Electrohypersensitivity as a Newly Identified and Characterized Neurologic Pathological Disorder: How to Diagnose, Treat, and Prevent It." International Journal of Molecular Sciences 21, no. 6 (March 11, 2020): 1915. http://dx.doi.org/10.3390/ijms21061915.
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Since 2009, we built up a database which presently includes more than 2000 electrohypersensitivity (EHS) and/or multiple chemical sensitivity (MCS) self-reported cases. This database shows that EHS is associated in 30% of the cases with MCS, and that MCS precedes the occurrence of EHS in 37% of these EHS/MCS-associated cases. EHS and MCS can be characterized clinically by a similar symptomatic picture, and biologically by low-grade inflammation and an autoimmune response involving autoantibodies against O-myelin. Moreover, 80% of the patients with EHS present with one, two, or three detectable oxidative stress biomarkers in their peripheral blood, meaning that overall these patients present with a true objective somatic disorder. Moreover, by using ultrasonic cerebral tomosphygmography and transcranial Doppler ultrasonography, we showed that cases have a defect in the middle cerebral artery hemodynamics, and we localized a tissue pulsometric index deficiency in the capsulo-thalamic area of the temporal lobes, suggesting the involvement of the limbic system and the thalamus. Altogether, these data strongly suggest that EHS is a neurologic pathological disorder which can be diagnosed, treated, and prevented. Because EHS is becoming a new insidious worldwide plague involving millions of people, we ask the World Health Organization (WHO) to include EHS as a neurologic disorder in the international classification of diseases.
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Malinova, Vesna, Karoline Dolatowski, Peter Schramm, Onnen Moerer, Veit Rohde, and Dorothee Mielke. "Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage." Journal of Neurosurgery 125, no. 1 (July 2016): 128–36. http://dx.doi.org/10.3171/2015.6.jns15720.
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OBJECT This prospective study investigated the role of whole-brain CT perfusion (CTP) studies in the identification of patients at risk for delayed ischemic neurological deficits (DIND) and of tissue at risk for delayed cerebral infarction (DCI). METHODS Forty-three patients with aneurysmal subarachnoid hemorrhage (aSAH) were included in this study. A CTP study was routinely performed in the early phase (Day 3). The CTP study was repeated in cases of transcranial Doppler sonography (TCD)–measured blood flow velocity (BFV) increase of > 50 cm/sec within 24 hours and/or on Day 7 in patients who were intubated/sedated. RESULTS Early CTP studies revealed perfusion deficits in 14 patients, of whom 10 patients (72%) developed DIND, and 6 of these 10 patients (60%) had DCI. Three of the 14 patients (21%) with early perfusion deficits developed DCI without having had DIND, and the remaining patient (7%) had neither DIND nor DCI. There was a statistically significant correlation between early perfusion deficits and occurrence of DIND and DCI (p < 0.0001). A repeated CTP was performed in 8 patients with a TCD–measured BFV increase > 50 cm/sec within 24 hours, revealing a perfusion deficit in 3 of them (38%). Two of the 3 patients (67%) developed DCI without preceding DIND and 1 patient (33%) had DIND without DCI. In 4 of the 7 patients (57%) who were sedated and/or comatose, additional CTP studies on Day 7 showed perfusion deficits. All 4 patients developed DCI. CONCLUSIONS Whole-brain CTP on Day 3 after aSAH allows early and reliable identification of patients at risk for DIND and tissue at risk for DCI. Additional CTP investigations, guided by TCD–measured BFV increase or persisting coma, do not contribute to information gain.
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Van Lieshout, Johannes J., Wouter Wieling, John M. Karemaker, and Niels H. Secher. "Syncope, cerebral perfusion, and oxygenation." Journal of Applied Physiology 94, no. 3 (March 1, 2003): 833–48. http://dx.doi.org/10.1152/japplphysiol.00260.2002.
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During standing, both the position of the cerebral circulation and the reductions in mean arterial pressure (MAP) and cardiac output challenge cerebral autoregulatory (CA) mechanisms. Syncope is most often associated with the upright position and can be provoked by any condition that jeopardizes cerebral blood flow (CBF) and regional cerebral tissue oxygenation (cO2Hb). Reflex (vasovagal) responses, cardiac arrhythmias, and autonomic failure are common causes. An important defense against a critical reduction in the central blood volume is that of muscle activity (“the muscle pump”), and if it is not applied even normal humans faint. Continuous tracking of CBF by transcranial Doppler-determined cerebral blood velocity ( Vmean) and near-infrared spectroscopy-determined cO2Hb contribute to understanding the cerebrovascular adjustments to postural stress; e.g., MAP does not necessarily reflect the cerebrovascular phenomena associated with (pre)syncope. CA may be interpreted as a frequency-dependent phenomenon with attenuated transfer of oscillations in MAP to Vmeanat low frequencies. The clinical implication is that CA does not respond to rapid changes in MAP; e.g., there is a transient fall in Vmeanon standing up and therefore a feeling of lightheadedness that even healthy humans sometimes experience. In subjects with recurrent vasovagal syncope, dynamic CA seems not different from that of healthy controls even during the last minutes before the syncope. Redistribution of cardiac output may affect cerebral perfusion by increased cerebral vascular resistance, supporting the view that cerebral perfusion depends on arterial inflow pressure provided that there is a sufficient cardiac output.
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Welton, K. Linnea, Tigran Garabekyan, Matthew J. Kraeutler, Laura A. Vogel-Abernathie, Daniel Raible, Jesse A. Goodrich, and Omer Mei-Dan. "Effects of Hip Arthroscopy Without a Perineal Post on Venous Blood Flow, Muscle Damage, Peripheral Nerve Conduction, and Perineal Injury: A Prospective Study." American Journal of Sports Medicine 47, no. 8 (May 24, 2019): 1931–38. http://dx.doi.org/10.1177/0363546519849663.
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Background: Prior reports of hip arthroscopy using a perineal post have established the risks of groin soft tissue injury, sexual dysfunction, and altered lower extremity neurovascular function. These parameters have not been investigated for hip arthroscopy without the use of a perineal post. Purpose: To evaluate the effects of postless hip arthroscopy on lower extremity venous blood flow, nerve conduction, muscle tissue damage, and perineal injury. Study Design: Case series; Level of evidence, 4. Methods: Patients between the ages of 18 and 50 years undergoing an elective unilateral or simultaneous bilateral hip arthroscopy were enrolled. Creatine phosphokinase (CPK)–MM levels and D-dimer levels were obtained preoperatively, immediately postoperatively, and 7 to 12 days postoperatively. Bilateral Doppler ultrasonography of the common femoral vein (CFV) and popliteal vein were conducted intraoperatively. Somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) were measured intraoperatively for the lower limbs. Perineal injury was assessed at 7 to 12 days postoperatively. Results: 35 patients underwent a total of 40 hip arthroscopies. No significant differences were found in venous blood flow between the operative and nonoperative legs for either the CFV or popliteal vein. SSEP monitoring of the peroneal nerve showed no significant reduction when traction was applied to the operative leg, 90.8%, compared with final measurement just before it was removed, 72.4% ( P = .09). For TcMEPs measured in the muscles outside of the traction boots, no significant changes were seen in the percentage of cases with abnormal measurements throughout the procedure. CPK-MM levels preoperatively, immediately postoperatively, and 7 to 12 days after surgery were on average 112, 190, and 102 IU/L, respectively (normal, <156 IU/L). No significant relationship was found between abnormal venous flow and altered D-dimer levels. No clinical evidence of nerve or vascular injury was encountered, and no groin soft tissue complications were observed during the study period. Conclusion: Postless hip arthroscopy is safe, without a notable reduction of venous blood flow or alteration of nerve function in the operative leg. Muscle tissue damage is subclinical, transient, and reduced compared with distraction with a post. No cases of perineal injury were observed during the study period.
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Saqqur, Maher, Esseddeeg Ghrooda, Aftab Ahmad, Khurshid Khan, Muhammad S. Hussain, and Ashfaq Shuaib. "The Combination of Clinical Features, Transcranial Doppler, and Alberta Stroke Program Early Computed Tomography Score (Computed Tomography Angiography) in Predicting Outcome in Intravenous Recombinant Tissue Plasminogen Activator-Treated Patients." Journal of Stroke and Cerebrovascular Diseases 25, no. 8 (August 2016): 2019–23. http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.12.013.
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