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Sample records for abnormal cerebral blood

  1. Regional cerebral blood flow abnormalities in chronic solvent abusers.

    PubMed

    Okada, S; Yamanouchi, N; Kodama, K; Uchida, Y; Hirai, S; Sakamoto, T; Noda, S; Komatsu, N; Sato, T

    1999-06-01

    This study aimed to reveal regional abnormalities of cerebral blood flow (CBF) and their relation to amotivational syndrome which causes poor social prognosis in solvent abusers Sixteen chronic solvent abusers (12 males and four females) along with five normal subjects underwent single photon emission computed tomography with N-isopropyl-p[123I]iodoamphetamine. The patients received a clinical evaluation with the Scale for the Assessment of Negative Symptoms. Using a semiquantitative method (normalized by the parietal cortex count), patients showed a statistically significant decrease in regional cerebral blood flow (rCBF) in the bilateral prefrontal cortices (P<0.01). In addition, the severity of hypoperfusion in the bilateral prefrontal cortices was related to the degree of severity of the avolition-apathy scale on SANS (left; P<0.05, right; P<0.01) even after excluding the effect of antipsychotics. These results suggest that rCBF abnormalities, especially in the prefrontal cortex, develop in chronic solvent abusers, and that this frontal hypoperfusion may be a biological basis of amotivational syndrome. PMID:10459736

  2. Regional cerebral blood flow abnormalities in Alzheimer's Disease

    SciTech Connect

    Rezai, K.; Damasio, H.; Graff-Radford, N.; Eslinger, P.; Kirchner, P.

    1985-05-01

    In 37 patients (ages 58-81) with senile dementia of Alzheimer type (SDAT), regional cerebral blood flow (rCBF) was studied utilizing a dedicated SPECT system (Tomomatic-64) that produces rCBF images from 4-minute clearance of Xenon-133 in the brain. The authors have modified the device to acquire 5 continuous tomographic slices simultaneously. A consistent pattern of diminished blood flow was seen in 33 patients in the posterior-temporal and lower-parietal brain regions. Computer programs were developed to quantitate the size of the affected brain tissue in the posterolateral brain areas (confined to the posterior 40% and the lateral 25% of the major and minor brain axes respectively). They have previously reported normal rCBF in 25 volunteers to be greater than 45 ml/min/100g with less than 10% regional variation. Hence, an area was considered abnormal if rCBF measured less than 40 ml/min/100g or was less than 70% of the mean rCBF value in the anterior temporal-frontal regions.

  3. Cerebral blood flow in normal and abnormal sleep and dreaming

    SciTech Connect

    Meyer, J.S.; Ishikawa, Y.; Hata, T.; Karacan, I.

    1987-07-01

    Measurements of regional or local cerebral blood flow (CBF) by the xenon-133 inhalation method and stable xenon computerized tomography CBF (CTCBF) method were made during relaxed wakefulness and different stages of REM and non-REM sleep in normal age-matched volunteers, narcoleptics, and sleep apneics. In the awake state, CBF values were reduced in both narcoleptics and sleep apneics in the brainstem and cerebellar regions. During sleep onset, whether REM or stage I-II, CBF values were paradoxically increased in narcoleptics but decreased severely in sleep apneics, while in normal volunteers they became diffusely but more moderately decreased. In REM sleep and dreaming CBF values greatly increased, particularly in right temporo-parietal regions in subjects experiencing both visual and auditory dreaming.

  4. Abnormal resting regional cerebral blood flow patterns and their correlates in schizophrenia

    SciTech Connect

    Mathew, R.J.; Wilson, W.H.; Tant, S.R.; Robinson, L.; Prakash, R.

    1988-06-01

    Regional cerebral blood flow (CBF) was measured under resting conditions in 108 right-handed schizophrenic inpatients and a matched group of normal controls with the xenon 133 inhalation technique. Forty-six patients were free of all medication for two weeks. There were no significant differences in CBF to the two hemispheres. The patients showed a comparatively reduced anteroposterior (AP) gradient for CBF. Though there were no differences in frontal flow, the patients had higher flow to several postcentral brain regions, bilaterally. Cerebral blood flow in the patients correlated inversely with age and positively with carbon dioxide level. Women had higher flow than men. Duration of the illness was the only significant predictor of the reduced AP gradient in patients. Higher left temporal and right parietal flow were found to be the best discriminators between patients and controls. Mean hemispheric flow to both hemispheres and several brain regions correlated with the total score and the item, unusual thought content, of the Brief Psychiatric Rating Scale. There were no differences in regional CBF between medicated and unmedicated patients.

  5. Abnormal cerebral vasodilation in aneurysmal subarachnoid hemorrhage: use of serial 133Xe cerebral blood flow measurement plus acetazolamide to assess cerebral vasospasm.

    PubMed

    Tran Dinh, Y R; Lot, G; Benrabah, R; Baroudy, O; Cophignon, J; Seylaz, J

    1993-10-01

    A patient with cerebral vasospasm following subarachnoid hemorrhage (SAH) was investigated by serial measurement of cerebral blood flow (CBF) using the xenon-133 emission tomography method. The CBF was measured before and after acetazolamide injection. On Day 2 after SAH, there was early local hyperperfusion in the middle cerebral artery (MCA) territory, ipsilateral to the left posterior communicating artery aneurysm. The regional CBF of this arterial territory decreased slightly after acetazolamide injection, probably because of vasoplegia and the "steal" phenomenon, and thus surgery was delayed. A right hemiplegia with aphasia and disturbed consciousness occurred 4 days later (on Day 6 after SAH) due to arterial vasospasm, despite treatment with a calcium-channel blocker. The initial hyperemia of the left MCA territory was followed by ischemia. The vasodilation induced by acetazolamide administration was significantly subnormal until Day 13, at which time CBF and vasoreactivity amplitude returned to normal and the patient's clinical condition improved. Surgery on Day 14 and outcome were without complication. It is concluded that serial CBF measurements plus acetazolamide injection are useful for monitoring the development of cerebral vasospasm to determine the most appropriate time for aneurysm surgery. PMID:8410215

  6. Multiple medullary venous malformations decreasing cerebral blood flow: Case report

    SciTech Connect

    Tomura, N.; Inugami, A.; Uemura, K.; Hadeishi, H.; Yasui, N. )

    1991-02-01

    A rare case of multiple medullary venous malformations in the right cerebral hemisphere is reported. The literature review yielded only one case of multiple medullary venous malformations. Computed tomography scan showed multiple calcified lesions with linear contrast enhancement representing abnormal dilated vessels and mild atrophic change of the right cerebral hemisphere. Single-photon emission computed tomography using N-isopropyl-p-({sup 123}I) iodoamphetamine demonstrated decreased cerebral blood flow in the right cerebral hemisphere.

  7. [Abnormal cerebral blood flow distributions during the post-ictal phase of febrile status epilepticus in three pediatric patients measured by arterial spin labeling perfusion MRI].

    PubMed

    Hirano, Keiko; Fukuda, Tokiko

    2016-05-01

    The ability to visualize brain perfusion is important for identifying epileptic foci. We present three pediatric cases showing asymmetrical cerebral blood flow (CBF) distributions during the post-ictal phase of febrile status epilepticus measured by arterial spin labeling (ASL) perfusion MRI. During the acute phase, regional CBF measurements in the areas considered including epileptic foci were higher than in the corresponding area of the contralateral hemisphere, though the exact quantitative value varied between cases. We could not identify the correct epileptogenic foci, because those ASL images were taken after the prolonged and extraordinary activation of neurons in the affected area. During the recovery phase, the differences reduced and the average regional CBF measurement was 54.6 ± 6.1 ml/100 g per minute, which was a little less than the number of previous ASL studies. ASL perfusion MRI imaging provides a method for evaluating regional CBF by using magnetically labeled arterial blood water as an endogenous tracer. With this technique, we can repeatedly evaluate both the brain structure and the level of perfusion at the same time. ASL is noninvasive and easily accessible, and therefore it could become a routine tool for assessment of perfusion in daily practice of pediatric neurology. PMID:27349086

  8. Abnormal regional cerebral blood flow found by technetium-99m ethyl cysteinate dimer brain single photon emission computed tomography in systemic lupus erythematosus patients with normal brain MRI findings.

    PubMed

    Chen, J J-H; Yen, R-F; Kao, A; Lin, C-C; Lee, C-C

    2002-11-01

    In this study, technetium-(99m) ethyl cysteinate dimer ((99m)Tc ECD) brain single photon emission computed tomography (SPECT) was used to detect regional cerebral blood flow (rCBF) of the brain in SLE patients with normal brain magnetic resonance imaging (MRI) findings. Twenty female SLE patients were enrolled in this study, divided into two groups. Group 1 consisted of 10 patients with neuropsychiatric manifestations. Group 2 consisted of 10 patients without neuropsychiatric manifestations. All patients had normal brain MRI findings. Another 10 SLE patients with abnormal MRI findings were included as group 3 for comparison. Meanwhile, 10 healthy female volunteers also underwent brain MRI and (99m)Tc ECD brain SPECT for comparison. The scans revealed hypoperfusion lesions in 9/20 (45%) SLE patients, including 7/10 (70%) cases in group 1 and 2/10 (20%) cases in group 2. In contrast, all 10 patients (100%) in group 3 had abnormal (99m)Tc ECD brain SPECT findings. The parietal lobes were the most commonly involved areas. We conclude that (99m)Tc ECD brain SPECT is more sensitive for detecting rCBF changes than is brain MRI in detecting the brain anatomic changes, and may have a diagnostic value in lupus cerebral involvement. However, (99m)Tc ECD brain SPECT may not be indicated for SLE patients with normal MRI and mild neuropsychiatric symptoms/signs, such headaches and dizziness. PMID:12447638

  9. Incidental Cerebral Microbleeds and Cerebral Blood Flow in Elderly Individuals

    PubMed Central

    Gregg, Nicholas M.; Kim, Albert E.; Gurol, M. Edip; Lopez, Oscar L.; Aizenstein, Howard J.; Price, Julie C.; Mathis, Chester A.; James, Jeffrey A.; Snitz, Beth E.; Cohen, Ann D.; Kamboh, M. Ilyas; Minhas, Davneet; Weissfeld, Lisa A.; Tamburo, Erica L.; Klunk, William E.

    2016-01-01

    IMPORTANCE Cerebral microbleeds (CMBs) are collections of blood breakdown products that are a common incidental finding in magnetic resonance imaging of elderly individuals. Cerebral microbleeds are associated with cognitive deficits, but the mechanism is unclear. Studies show that individuals with CMBs related to symptomatic cerebral amyloid angiopathy have abnormal vascular reactivity and cerebral blood flow (CBF), but, to our knowledge, abnormalities in cerebral blood flow have not been reported for healthy individuals with incidental CMBs. OBJECTIVE To evaluate the association of incidental CMBs with resting-state CBF, cerebral metabolism, cerebrovascular disease, β-amyloid (Aβ), and cognition. DESIGN, SETTING, AND PARTICIPANTS A cross-sectional study of 55 cognitively normal individuals with a mean (SD) age of 86.8 (2.7) years was conducted from May 1, 2010, to May 1, 2013, in an academic medical center in Pittsburgh; data analysis was performed between June 10, 2013, and April 9, 2015. INTERVENTIONS 3-Tesla magnetic resonance imaging was performed with susceptibility-weighted imaging or gradient-recalled echo to assess CMBs, arterial spin labeling for CBF, and T1- and T2-weighted imaging for atrophy, white matter hyperintensities, and infarcts. Positron emission tomography was conducted with fluorodeoxyglucose to measure cerebral metabolism and Pittsburgh compound B for fibrillar Aβ. Neuropsychological evaluation, including the Clinical Dementia Rating scale, was performed. MAIN OUTCOMES AND MEASURES Magnetic resonance images were rated for the presence and location of CMBs. Lobar CMBs were subclassified as cortical or subcortical. Measurements of CBF, metabolism, and Aβ were compared with the presence and number of CMBs with voxelwise and region-of-interest analyses. RESULTS The presence of cortical CMBs was associated with significantly reduced CBF in multiple regions on voxelwise and region-of-interest analyses (percentage difference in global CBF,

  10. Blood flow distribution in cerebral arteries

    PubMed Central

    Zarrinkoob, Laleh; Ambarki, Khalid; Wåhlin, Anders; Birgander, Richard; Eklund, Anders; Malm, Jan

    2015-01-01

    High-resolution phase–contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra- and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717±123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21% distal MCA, 6% anterior cerebral artery (ACA), 12%, distal ACA, 4% ophthalmic artery, 2% posterior cerebral artery (PCA), 8% and 20% to basilar artery. Deviating distributions were observed in subjects with ‘fetal' PCA. Blood flow rate in cerebral arteries decreased with increasing age (P<0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61±8; men: 55±6 mL/min/100 mL, P<0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system. PMID:25564234

  11. Multifractality of cerebral blood flow

    NASA Astrophysics Data System (ADS)

    West, Bruce J.; Latka, Miroslaw; Glaubic-Latka, Marta; Latka, Dariusz

    2003-02-01

    Scale invariance, the property relating time series across multiple scales, has provided a new perspective of physiological phenomena and their underlying control systems. The traditional “signal plus noise” paradigm of the engineer was first replaced with a model in which biological time series have a fractal structure in time (Fractal Physiology, Oxford University Press, Oxford, 1994). This new paradigm was subsequently shown to be overly restrictive when certain physiological signals were found to be characterized by more than one scaling parameter and therefore to belong to a class of more complex processes known as multifractals (Fractals, Plenum Press, New York, 1988). Here we demonstrate that in addition to heart rate (Nature 399 (1999) 461) and human gait (Phys. Rev. E, submitted for publication), the nonlinear control system for cerebral blood flow (CBF) (Phys. Rev. Lett., submitted for publication; Phys. Rev. E 59 (1999) 3492) is multifractal. We also find that this multifractality is greatly reduced for subjects with “serious” migraine and we present a simple model for the underlying control process to describe this effect.

  12. Multiple sphingolipid abnormalities following cerebral microendothelial hypoxia

    PubMed Central

    Testai, Fernando D.; Kilkus, John P.; Berdyshev, Evgeny; Gorshkova, Irina; Natarajan, Viswanathan; Dawson, Glyn

    2015-01-01

    Hypoxia has been previously shown to inhibit the dihydroceramide (DHC) desaturase, leading to the accumulation of DHC. In this study, we used metabolic labeling with [3H]-palmitate, HPLC/MS/MS analysis, and specific inhibitors to show numerous sphingolipid changes after oxygen deprivation in cerebral microendothelial cells. The increased DHC, particularly long-chain forms, was observed in both whole cells and detergent-resistant membranes. This was reversed by reoxygenation and blocked by the de novo sphingolipid synthesis inhibitor myriocin, but not by the neutral sphingomyelinase inhibitor GW-4869. Furthermore, oxygen deprivation of microendothelial cells increased levels of dihydro-sphingosine (DH-Sph), DH-sphingosine1-phosphate (DH-S1P), DH-sphingomyelin (DH-SM), DH-glucosylceramide (DH-GlcCer), and S1P levels. In vitro assays revealed no changes in the activity of sphingomyelinases or sphingomyelin synthase, but resulted in reduced S1P lyase activity and 40% increase in glucosylceramide synthase (GCS) activity, which was reversed by reoxygenation. Inhibition of the de novo sphingolipid pathway (myriocin) or GCS (EtPoD4) induced endothelial barrier dysfunction and increased caspase 3-mediated cell death in response to hypoxia. Our findings suggest that hypoxia induces synthesis of S1P and multiple dihydrosphingolipids, including DHC, DH-SM, DH-GlcCer, DH-Sph and DH-S1P, which may be involved in ameliorating the effects of stroke. PMID:25060904

  13. Cerebral blood flow velocity in two patients with neonatal cerebral infarction.

    PubMed

    Nishimaki, S; Seki, K; Yokota, S

    2001-04-01

    Cerebral blood flow velocity was measured in the middle cerebral artery of two patients who exhibited unilateral neonatal cerebral infarction during the neonatal period. Doppler studies demonstrated increases in cerebral blood flow velocity but decreases in the resistance index on the affected side of the middle cerebral artery in the neonate who developed hemiplegia with cystic encephalomalacia, although the neonate with normal neurologic outcome exhibited symmetric cerebral blood flow velocity and resistance index. The asymmetry in cerebral blood flow velocity measurements of both middle cerebral arteries may be useful to evaluate the severity of brain damage and predict the neurodevelopmental prognosis of unilateral neonatal cerebral infarction. PMID:11377112

  14. Early Blood Gas Abnormalities and the Preterm Brain

    PubMed Central

    Leviton, Alan; Allred, Elizabeth; Kuban, Karl C. K.; Dammann, Olaf; O'Shea, T. Michael; Hirtz, Deborah; Schreiber, Michael D.; Paneth, Nigel

    2010-01-01

    The authors explored associations between blood gas abnormalities in more than 1,000 preterm infants during the first postnatal days and indicators of neonatal brain damage. During 2002–2004, women delivering infants before 28 weeks’ gestation at one of 14 participating institutions in 5 US states were asked to enroll in the study. The authors compared infants with blood gas values in the highest or lowest quintile for gestational age and postnatal day (extreme value) on at least 1 of the first 3 postnatal days with the remainder of the subjects, with separate analyses for blood gas abnormalities on multiple days and for partial pressure of oxygen in the alveolar gas of <35. Outcomes analyzed were ventriculomegaly and an echolucent lesion on an ultrasound scan in the neonatal intensive care unit, and cerebral palsy, microcephaly, and a low score on a Bayley Scale of Infant Development at 24 months. Every blood gas derangement (hypoxemia, hyperoxemia, hypocapnia, hypercapnia, and acidosis) was associated with multiple indicators of brain damage. However, for some, the associations were seen with only 1 day of exposure; others were evident with 2 or more days’ exposure. Findings suggest that individual blood gas derangements do not increase brain damage risk. Rather, the multiple derangements associated with indicators of brain damage might be indicators of immaturity/vulnerability and illness severity. PMID:20807736

  15. Optoacoustic monitoring of cerebral venous blood oxygenation through extracerebral blood

    PubMed Central

    Petrov, I. Y.; Petrov, Y.; Prough, D. S.; Deyo, D. J.; Cicenaite, I.; Esenaliev, R. O.

    2011-01-01

    There is strong clinical evidence that controlling cerebral venous oxygenation (oxyhemoglobin saturation) is critically important for patients with severe traumatic brain injury as well as for patients undergoing cardiac surgery. However, the only available method for cerebral venous blood oxygenation monitoring is invasive and requires catheterization of the internal jugular vein. We designed and built a novel optoacoustic monitor of cerebral venous oxygenation as measured in the superior sagittal sinus (SSS), the large midline cerebral vein. To the best of our knowledge, optical monitoring of cerebral venous blood oxygenation through overlying extracerebral blood is reported for the first time in this paper. The system was capable of detecting SSS signals in vivo at 700, 800, and 1064 nm through the thick (5–6 mm) sheep skull containing the circulating blood. The high (submillimeter) in-depth resolution of the system provided identification of the SSS peaks in the optoacoustic signals. The SSS peak amplitude closely followed the actual SSS blood oxygenation measured invasively using catheterization, blood sampling, and “gold standard” CO-Oximetry. Our data indicate the system may provide accurate measurement of the SSS blood oxygenation in patients with extracerebral blood over the SSS. PMID:22254173

  16. Cerebral venous hemodynamic abnormalities in episodic and chronic migraine

    PubMed Central

    Petolicchio, Barbara; Viganò, Alessandro; di Biase, Lazzaro; Tatulli, Doriana; Toscano, Massimiliano; Vicenzini, Edoardo; Passarelli, Francesco; Di Piero, Vittorio

    2016-01-01

    Summary Alterations of cerebral venous drainage have been demonstrated in chronic migraine (CM), suggesting that cerebral venous hemodynamic abnormalities (CVHAs) play a role in this condition. The aim of the present study was to look for a correlation between CM and CVHAs. We recruited 33 subjects suffering from CM with or without analgesic overuse, 29 episodic migraine (EM) patients with or without aura, and 21 healthy subjects as controls (HCs). CVHAs were evaluated by transcranial and extracranial echo-color Doppler evaluation of five venous hemodynamic parameters. CVHAs were significantly more frequent in the CM and EM patients than in the HCs. In the migraine patients, CVHAs were not correlated with clinical features. The significantly greater frequency of CVHAs observed in the migraineurs may reflect a possible relationship between migraine and these abnormalities. Prospective longitudinal studies are needed to investigate whether CVHAs have a role in the processes of migraine chronification. PMID:27358220

  17. Diabetic patients have abnormal cerebral autoregulation during cardiopulmonary bypass

    SciTech Connect

    Croughwell, N.; Lyth, M.; Quill, T.J.; Newman, M.; Greeley, W.J.; Smith, L.R.; Reves, J.G. )

    1990-11-01

    We tested the hypothesis that insulin-dependent diabetic patients with coronary artery bypass graft surgery experience altered coupling of cerebral blood flow and oxygen consumption. In a study of 23 patients (11 diabetics and 12 age-matched controls), cerebral blood flow was measured using 133Xe clearance during nonpulsatile, alpha-stat blood gas managed cardiopulmonary bypass at the conditions of hypothermia and normothermia. In diabetic patients, the cerebral blood flow at 26.6 +/- 2.42 degrees C was 25.3 +/- 14.34 ml/100 g/min and at 36.9 +/- 0.58 degrees C it was 27.3 +/- 7.40 ml/100 g/min (p = NS). The control patients increased cerebral blood flow from 20.7 +/- 6.78 ml/100 g/min at 28.4 +/- 2.81 degrees C to 37.6 +/- 8.81 ml/100 g/min at 36.5 +/- 0.45 degrees C (p less than or equal to 0.005). The oxygen consumption was calculated from jugular bulb effluent and increased from hypothermic values of 0.52 +/- 0.20 ml/100 g/min in diabetics to 1.26 +/- 0.28 ml/100 g/min (p = 0.001) at normothermia and rose from 0.60 +/- 0.27 to 1.49 +/- 0.35 ml/100 g/min (p = 0.0005) in the controls. Thus, despite temperature-mediated changes in oxygen consumption, diabetic patients did not increase cerebral blood flow as metabolism increased. Arteriovenous oxygen saturation gradients and oxygen extraction across the brain were calculated from arterial and jugular bulb blood samples. The increase in arteriovenous oxygen difference between temperature conditions in diabetic patients and controls was significantly different (p = 0.01). These data reveal that diabetic patients lose cerebral autoregulation during cardiopulmonary bypass and compensate for an imbalance in adequate oxygen delivery by increasing oxygen extraction.

  18. Update on cerebral uptake of blood ammonia.

    PubMed

    Sørensen, Michael

    2013-06-01

    Ammonia is believed to play a key role in the development of hepatic encephalopathy (HE) with increased formation of glutamine playing a central role. It has been debated whether blood ammonia enters the brain by passive diffusion and/or active transport by ion-transporters and that changes in blood pH could affect the blood-to-brain transfer of ammonia. It has also been proposed that the permeability-surface area product for ammonia across the blood-brain barrier (PSBBB) should be increased in cirrhosis and HE. In the present paper it is argued that changes in blood pH does not alter PSBBB for ammonia and the question of passive diffusion versus active transport of ammonia remains unresolved. Furthermore, recent studies do not find evidence for increased PSBBB for ammonia in cirrhosis. The main determent for cerebral uptake of blood ammonia (i.e. flux) is the arterial blood ammonia concentration. This means that the only way to protect the brain from hyperammonemia is by lowering blood ammonia, inhibit cerebral uptake of ammonia, or by manipulating cerebral ammonia metabolism so that less glutamine is produced. PMID:23479402

  19. Regional cerebral blood flow in schizophrenia

    SciTech Connect

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-10-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions.

  20. SPECT study of regional cerebral blood flow in Alzheimer disease

    SciTech Connect

    Bonte, F.J.; Ross, E.D.; Chehabi, H.H.; Devous, M.D. Sr.

    1986-07-01

    A common cause of dementia in late midlife and old age is Alzheimer disease (AD), which affects more than one in 20 individuals over the age of 65. Past studies of regional cerebral blood flow (rCBF) in patients with AD here suggested blood flow abnormalities, but findings have differed. We have studied 37 patients diagnosed as having AD with inhalation and washout of /sup 133/Xe and single-photon emission computed tomography (SPECT), obtaining evidence of abnormal rCBF patterns in 19. Flow reductions were most common in the temporoparietal regions and were occasionally found in the frontal areas. Investigators using positron-emission tomography (PET) have identified similar findings with respect to rCBF and regional oxygen, glucose, and protein metabolism. The SPECT determination of rCBF, which gives information similar to that provided by PET, may assume importance in the diagnosis of AD and in the differential diagnosis of the dementias.

  1. REM sleep abnormalities in severe athetoid cerebral palsy.

    PubMed

    Hayashi, M; Inoue, Y; Iwakawa, Y; Sasaki, H

    1990-01-01

    Various abnormalities of sleep have been reported in extrapyramidal diseases in adults. We have investigated the disturbances of REM sleep (SREM) in severe athetoid cerebral palsy (ACP) originating perinatally. Ten ACP patients, 5 males and 5 females ranging from 15 to 30 years old, were studied by means of all-night polygraphic examination. Three cases showed a marked decrease in rapid eye movements in SREM. Moreover, the tone of submental muscle in SREM was also disturbed in three. Regarding body movements during sleep, gross movements and twitch movements of the submental muscle were analyzed. In most of the patients, an abnormal distribution of body movements according to sleep stages was observed, the rate being significantly reduced in SREM. REMs, atonia and body movements are considered to be related to the brainstem function in animals. The results of the present study suggest that perinatal extrapyramidal diseases could also coincide with brainstem dysfunctions. PMID:2288380

  2. Cerebral blood flow in humans following resuscitation from cardiac arrest

    SciTech Connect

    Cohan, S.L.; Mun, S.K.; Petite, J.; Correia, J.; Tavelra Da Silva, A.T.; Waldhorn, R.E.

    1989-06-01

    Cerebral blood flow was measured by xenon-133 washout in 13 patients 6-46 hours after being resuscitated from cardiac arrest. Patients regaining consciousness had relatively normal cerebral blood flow before regaining consciousness, but all patients who died without regaining consciousness had increased cerebral blood flow that appeared within 24 hours after resuscitation (except in one patient in whom the first measurement was delayed until 28 hours after resuscitation, by which time cerebral blood flow was increased). The cause of the delayed-onset increase in cerebral blood flow is not known, but the increase may have adverse effects on brain function and may indicate the onset of irreversible brain damage.

  3. Cerebral blood flow variations in CNS lupus

    SciTech Connect

    Kushner, M.J.; Tobin, M.; Fazekas, F.; Chawluk, J.; Jamieson, D.; Freundlich, B.; Grenell, S.; Freemen, L.; Reivich, M. )

    1990-01-01

    We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery.

  4. Cerebral glucose metabolic abnormality in patients with congenital scoliosis.

    PubMed

    Park, Weon Wook; Suh, Kuen Tak; Kim, Jeung Il; Ku, Ja Gyung; Lee, Hong Seok; Kim, Seong-Jang; Kim, In-Ju; Kim, Yong-Ki; Lee, Jung Sub

    2008-07-01

    A possible association between congenital scoliosis and low mental status has been recognized, but there are no reports describing the mental status or cerebral metabolism in patients with congenital scoliosis in detail. We investigated the mental status using a mini-mental status exam as well as the cerebral glucose metabolism using F-18 fluorodeoxyglucose brain positron emission tomography in 12 patients with congenital scoliosis and compared them with those of 14 age-matched patients with adolescent idiopathic scoliosis. The mean mini-mental status exam score in the congenital scoliosis group was significantly lower than that in the adolescent idiopathic scoliosis group. Group analysis found that various brain areas of patients with congenital scoliosis showed glucose hypometabolisms in the left prefrontal cortex (Brodmann area 10), right orbitofrontal cortex (Brodmann area 11), left dorsolateral prefrontal cortex (Brodmann area 9), left anterior cingulate gyrus (Brodmann area 24) and pulvinar of the left thalamus. From this study, we could find the metabolic abnormalities of brain in patients with congenital scoliosis and suggest the possible role of voxel-based analysis of brain fluorodeoxyglucose positron emission tomography. PMID:18446384

  5. Cerebral blood flow in normal pressure hydrocephalus

    SciTech Connect

    Mamo, H.L.; Meric, P.C.; Ponsin, J.C.; Rey, A.C.; Luft, A.G.; Seylaz, J.A.

    1987-11-01

    A xenon-133 method was used to measure cerebral blood flow (CBF) before and after cerebrospinal fluid (CSF) removal in patients with normal pressure hydrocephalus (NPH). Preliminary results suggested that shunting should be performed on patients whose CBF increased after CSF removal. There was a significant increase in CBF in patients with NPH, which was confirmed by the favorable outcome of 88% of patients shunted. The majority of patients with senile and presenile dementia showed a decrease or no change in CBF after CSF removal. It is suggested that although changes in CBF and clinical symptoms of NPH may have the same cause, i.e., changes in the cerebral intraparenchymal pressure, there is no simple direct relation between these two events. The mechanism underlying the loss of autoregulation observed in NPH is also discussed.

  6. Intraoperative cerebral blood flow imaging of rodents

    NASA Astrophysics Data System (ADS)

    Li, Hangdao; Li, Yao; Yuan, Lu; Wu, Caihong; Lu, Hongyang; Tong, Shanbao

    2014-09-01

    Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats.

  7. Cerebral blood flow in sickle cell cerebrovascular disease

    SciTech Connect

    Huttenlocher, P.R.; Moohr, J.W.; Johns, L.; Brown, F.D.

    1984-05-01

    Cerebral blood flow (CBF) has been studied by the xenon-133 (/sup 133/Xe) inhalation method in 16 children with suspected sickle cell cerebrovascular disease. Abnormalities consisting of decreases in total, hemispheral, or regional CBF were found in 17 of 26 studies. Eleven studies performed immediately after stroke, transient ischemic attack, or depression of state of alertness showed abnormalities. In addition to confirming regional cerebrovascular insufficiency in children with stroke due to major cerebral artery occlusion, the method detected diffuse decrease in CBF in children with stupor, coma, and seizures who had normal angiographic findings. In contrast, six of seven studies obtained after exchange transfusion or during maintenance on hypertransfusion therapy showed normal findings. The difference between results in patients with acute neurologic disturbances and those receiving transfusion therapy was statistically significant (P less than .005). The data indicate that the /sup 133/Xe method reliably demonstrates cerebrovascular impairment in sickle cell disease. They also suggest that CBF changes in patients with sickle cell disease can be reversed by exchange transfusion and by hypertransfusion therapy. The /sup 133/Xe CBF method may be useful for following up children with sickle cell disease who are at high risk for recurrent stroke.

  8. Cerebral blood flow at high altitude.

    PubMed

    Ainslie, Philip N; Subudhi, Andrew W

    2014-06-01

    This brief review traces the last 50 years of research related to cerebral blood flow (CBF) in humans exposed to high altitude. The increase in CBF within the first 12 hours at high altitude and its return to near sea level values after 3-5 days of acclimatization was first documented with use of the Kety-Schmidt technique in 1964. The degree of change in CBF at high altitude is influenced by many variables, including arterial oxygen and carbon dioxide tensions, oxygen content, cerebral spinal fluid pH, and hematocrit, but can be collectively summarized in terms of the relative strengths of four key integrated reflexes: 1) hypoxic cerebral vasodilatation; 2) hypocapnic cerebral vasoconstriction; 3) hypoxic ventilatory response; and 4) hypercapnic ventilatory response. Understanding the mechanisms underlying these reflexes and their interactions with one another is critical to advance our understanding of global and regional CBF regulation. Whether high altitude populations exhibit cerebrovascular adaptations to chronic levels of hypoxia or if changes in CBF are related to the development of acute mountain sickness are currently unknown; yet overall, the integrated CBF response to high altitude appears to be sufficient to meet the brain's large and consistent demand for oxygen. This short review is organized as follows: An historical overview of the earliest CBF measurements collected at high altitude introduces a summary of reported CBF changes at altitude over the last 50 years in both lowlanders and high-altitude natives. The most tenable candidate mechanism(s) regulating CBF at altitude are summarized with a focus on available data in humans, and a role for these mechanisms in the pathophysiology of AMS is considered. Finally, suggestions for future directions are provided. PMID:24971767

  9. Mapping cerebral blood flow by xenon-enhanced computed tomography: clinical experience

    SciTech Connect

    Yonas, H.; Good, W.F.; Gur, D.; Wolfson, S.K. Jr.; Latchaw, R.E.; Good, B.C.; Leanza, R.; Miller, S.L.

    1984-08-01

    Local cerebral blood flow was measured and mapped using xenon-enhanced x-ray transmission computed tomography. Studies involving 4-6 minutes of xenon-oxygen inhalation can be performed routinely in awake and anesthetized patients with acceptable patient tolerance and compliance. Several case studies of patients with acute and chronic ischemic injuries and other cerebral abnormalities are presented to illustrate characterization of flow pattern in normal and abnormal tissue, as well as the relevance of this flow information to clinical patient management.

  10. Assessment of Specific Characteristics of Abnormal General Movements: Does It Enhance the Prediction of Cerebral Palsy?

    ERIC Educational Resources Information Center

    Hamer, Elisa G.; Bos, Arend F.; Hadders-Algra, Mijna

    2011-01-01

    Aim: Abnormal general movements at around 3 months corrected age indicate a high risk of cerebral palsy (CP). We aimed to determine whether specific movement characteristics can improve the predictive power of definitely abnormal general movements. Method: Video recordings of 46 infants with definitely abnormal general movements at 9 to 13 weeks…

  11. Alterations in regional cerebral blood flow in neonatal stroke: preliminary findings with color Doppler sonography.

    PubMed

    Taylor, G A

    1994-01-01

    Little information is available regarding alterations in regional cerebral blood flow and vascularity on cranial sonography in infants with focal ischemic brain injury. This study describes the use of color Doppler sonography in the characterization of these changes following acute neonatal stroke. Color Doppler examinations were performed as part of the series of clinically indicated cranial sonograms in eight infants with clinical, sonographic, and CT evidence of acute cerebral infarction. The cerebral vascularity of each hemisphere was assessed for symmetry and for presence of abnormal blood vessels. Initial Doppler study in four infants with hypoxic-ischemic infarcts showed increased size and number of visible vessels in the periphery of the infarct and increased mean blood flow velocity in vessels supplying or draining the infarcted areas. Diminished vessel number and size and frequency shifts suggestive of decreased hemispheric perfusion was identified in one infant with middle cerebral artery insufficiency. Repeat Doppler studies were performed on two infants. These showed the development of multiple small, irregular blood vessels in the periphery of the infarct. Focal abnormalities in regional cerebral blood flow may be present as part of the normal healing process following neonatal stroke, and can be demonstrated with color Doppler sonography. PMID:7915832

  12. Noninvasive optoacoustic monitoring of cerebral venous blood oxygenation in newborns

    NASA Astrophysics Data System (ADS)

    Petrov, Irene Y.; Wynne, Karon E.; Petrov, Yuriy; Esenaliev, Rinat O.; Richardson, C. Joan; Prough, Donald S.

    2012-02-01

    Cerebral ischemia after birth and during labor is a major cause of death and severe complications such as cerebral palsy. In the USA alone, cerebral palsy results in permanent disability of 10,000 newborns per year and approximately 500,000 of the total population. Currently, no technology is capable of direct monitoring of cerebral oxygenation in newborns. This study proposes the use of an optoacoustic technique for noninvasive cerebral ischemia monitoring by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, near-infrared optoacoustic system suitable for noninvasive monitoring of cerebral ischemia in newborns with normal weight (NBW), low birth-weight (LBW, 1500 - 2499 g) and very low birth-weight (VLBW, < 1500 g). The system was capable of detecting SSS signals through the open anterior and posterior fontanelles as well as through the skull. We tested the system in NBW, LBW, and VLBW newborns (weight range: from 675 g to 3,000 g) admitted to the neonatal intensive care unit. We performed single and continuous measurements of the SSS blood oxygenation. The data acquisition, processing and analysis software developed by our group provided real-time, absolute SSS blood oxygenation measurements. The SSS blood oxygenation ranged from 60% to 80%. Optoacoustic monitoring of the SSS blood oxygenation provides valuable information because adequate cerebral oxygenation would suggest that no therapy was necessary; conversely, evidence of cerebral ischemia would prompt therapy to increase cerebral blood flow.

  13. Cerebral blood volume changes during brain activation

    PubMed Central

    Krieger, Steffen Norbert; Streicher, Markus Nikolar; Trampel, Robert; Turner, Robert

    2012-01-01

    Cerebral blood volume (CBV) changes significantly with brain activation, whether measured using positron emission tomography, functional magnetic resonance imaging (fMRI), or optical microscopy. If cerebral vessels are considered to be impermeable, the contents of the skull incompressible, and the skull itself inextensible, task- and hypercapnia-related changes of CBV could produce intolerable changes of intracranial pressure. Because it is becoming clear that CBV may be useful as a well-localized marker of neural activity changes, a resolution of this apparent paradox is needed. We have explored the idea that much of the change in CBV is facilitated by exchange of water between capillaries and surrounding tissue. To this end, we developed a novel hemodynamic boundary-value model and found approximate solutions using a numerical algorithm. We also constructed a macroscopic experimental model of a single capillary to provide biophysical insight. Both experiment and theory model capillary membranes as elastic and permeable. For a realistic change of input pressure, a relative pipe volume change of 21±5% was observed when using the experimental setup, compared with the value of approximately 17±1% when this quantity was calculated from the mathematical model. Volume, axial flow, and pressure changes are in the expected range. PMID:22569192

  14. Gender differences in regional cerebral blood flow

    SciTech Connect

    Gur, R.E.; Gur, R.C. )

    1990-01-01

    Gender differences have been noted in neurobehavioral studies. The 133xenon inhalation method for measuring regional cerebral blood flow (rCBF) can contribute to the understanding of the neural basis of gender differences in brain function. Few studies have examined gender differences in rCBF. In studies of normal subjects, women have higher rates of CBF than men, and this is related to age. Usually by the sixth decade men and women have similar flow rates. Fewer studies on rCBF in schizophrenia have examined sex differences. The pattern of higher flows for females maintains, but its correlates with gender differences in clinical as well as other parameters of brain function remain to be examined.

  15. Laser Speckle Imaging of Cerebral Blood Flow

    NASA Astrophysics Data System (ADS)

    Luo, Qingming; Jiang, Chao; Li, Pengcheng; Cheng, Haiying; Wang, Zhen; Wang, Zheng; Tuchin, Valery V.

    Monitoring the spatio-temporal characteristics of cerebral blood flow (CBF) is crucial for studying the normal and pathophysiologic conditions of brain metabolism. By illuminating the cortex with laser light and imaging the resulting speckle pattern, relative CBF images with tens of microns spatial and millisecond temporal resolution can be obtained. In this chapter, a laser speckle imaging (LSI) method for monitoring dynamic, high-resolution CBF is introduced. To improve the spatial resolution of current LSI, a modified LSI method is proposed. To accelerate the speed of data processing, three LSI data processing frameworks based on graphics processing unit (GPU), digital signal processor (DSP), and field-programmable gate array (FPGA) are also presented. Applications for detecting the changes in local CBF induced by sensory stimulation and thermal stimulation, the influence of a chemical agent on CBF, and the influence of acute hyperglycemia following cortical spreading depression on CBF are given.

  16. Regional cerebral blood flow measurement with intravenous ( sup 15 O)water bolus and ( sup 18 F)fluoromethane inhalation

    SciTech Connect

    Herholz, K.; Pietrzyk, U.; Wienhard, K.; Hebold, I.; Pawlik, G.; Wagner, R.; Holthoff, V.; Klinkhammer, P.; Heiss, W.D. )

    1989-09-01

    In 20 patients with ischemic cerebrovascular disease, classic migraine, or angiomas, we compared paired dynamic positron emission tomographic measurements of regional cerebral blood flow using both ({sup 15}O)water and ({sup 18}F)fluoromethane as tracers. Cerebral blood flow was also determined according to the autoradiographic technique with a bolus injection of ({sup 15}O)water. There were reasonable overall correlations between dynamic ({sup 15}O)water and ({sup 18}F)fluoromethane values for cerebral blood flow (r = 0.82) and between dynamic and autoradiographic ({sup 15}O)water values for cerebral blood flow (r = 0.83). We found a close correspondence between abnormal pathologic findings and visually evaluated cerebral blood flow tomograms obtained with the two tracers. On average, dynamic ({sup 15}O)water cerebral blood flow was 6% lower than that measured with ({sup 18}F)fluoromethane. There also was a general trend toward a greater underestimation with ({sup 15}O)water in high-flow areas, particularly in hyperemic areas, probably due to incomplete first-pass extraction of ({sup 15}O)water. Underestimation was not detected in low-flow areas or in the cerebellum. Absolute cerebral blood flow values were less closely correlated between tracers and techniques than cerebral blood flow patterns. The variability of the relation between absolute flow values was probably caused by confounding effects of the variation in the circulatory delay time. The autoradiographic technique was most sensitive to this type error.

  17. [A Case of Ruptured Peripheral Cerebral Aneurysm at Abnormal Vessels Associated with Middle Cerebral Artery Stenosis:Similarity to Moyamoya Disease].

    PubMed

    Miyazaki, Hajime; Kohno, Kanehisa; Tanaka, Hideo; Fukumoto, Shinya; Ichikawa, Haruhisa; Onoue, Shinji; Fumoto, Noriyuki; Ozaki, Saya; Maeda, Toshiharu

    2016-04-01

    We report a case of ruptured peripheral cerebral aneurysm at abnormal vessels associated with severe stenosis at the middle cerebral artery (MCA). A 66-year-old woman was admitted at our hospital with headache on foot. Computed tomography (CT) showed intracerebral hemorrhage in the left fronto-basal area. Three-dimensional-CT and conventional angiogram revealed abnormal vessels, which were similar to those seen in moyamoya disease, with a small enhancement close to the hematoma. On day 11, subsequent cerebral angiogram demonstrated an aneurysm at the peripheral portion of an abnormal vessel arising from the left A2. On day 17, soon after the diagnosis of the ruptured aneurysm was made (while still at the subacute stage), we operated on the aneurysm. Superficial temporal artery (STA)-MCA anastomosis was also performed to preserve cerebral blood flow and reduce hemodynamic stress. Several days after the operation, she had transient aphasia due to hyperperfusion of the MCA territory, but eventually recovered with no neurological deficit at discharge. Follow-up study revealed revascularization from the branches of the external carotid artery as well as the STA. On admission, we initially thought that this patient had abnormal vessels associated with arteriosclerotic MCA stenosis. However, the postoperative clinical course as well as the histopathological specimens of both the abnormal artery with the aneurysm and the STA revealed similar findings to those of moyamoya disease. Although this case did not satisfy the criteria for moyamoya disease, it is conceivable that a single arterial occlusive lesion associated with moyamoya-like vessels might develop in the same mechanism with that of moyamoya disease. PMID:27056872

  18. The Role of Neuronal Signaling in Controlling Cerebral Blood Flow

    ERIC Educational Resources Information Center

    Drake, Carrie T.; Iadecola, Costantino

    2007-01-01

    Well-regulated blood flow within the brain is vital to normal function. The brain's requirement for sufficient blood flow is ensured by a tight link between neural activity and blood flow. The link between regional synaptic activity and regional cerebral blood flow, termed functional hyperemia, is the basis for several modern imaging techniques…

  19. Regional cerebral blood flow changes associated with ethanol intoxication

    SciTech Connect

    Mathew, R.J.; Wilson, W.H.

    1986-11-01

    Regional cerebral blood flow (CBF) was measured via the 133Xenon inhalation technique in 26 healthy volunteers before and 60 minutes after the oral administration of ethyl alcohol or placebo on a double-blind basis. The cerebral blood flow values, corrected for test-retest differences in carbon dioxide showed a significant bilateral increase after ethanol administration. Blood levels of ethanol, estimated with a breath analyser, did not correlate with the CBF changes.

  20. Cerebral blood flow tomography with xenon-133

    SciTech Connect

    Lassen, N.A.

    1985-10-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-/sup 133/. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical and investigative purposes. This article discusses in particular its use for the selection of patients with carotid occlusion for extracranial/intracranial bypass surgery, for detection of severe arterial spasm after aneurysm bleeding, and for detection of low flow areas during severe migraine attacks. The use of other tracers for CBF tomography using SPECT is summarized with emphasis on the /sup 99m/Tc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers.

  1. Abnormality of low frequency cerebral hemodynamics oscillations in TBI population.

    PubMed

    Chernomordik, Victor; Amyot, Franck; Kenney, Kimbra; Wassermann, Eric; Diaz-Arrastia, Ramon; Gandjbakhche, Amir

    2016-05-15

    Functional Near Infrared Spectroscopy (fNIRS) can non-invasively capture dynamic cognitive activation and underlying physiological processes by measuring changes in oxy- and deoxy-hemoglobin levels, correlated to brain activation. It is a portable, inexpensive and user-friendly device which is easily adapted to the outpatient setting for the assessment of cognitive functions after Traumatic Brain Injury (TBI). Low frequency oscillations in hemodynamic signal, attributed in the literature to cerebral autoregulation, were assessed using recently introduced metrics, Oxygenation Variability (OV Index), obtained from oxy/deoxy-hemoglobin variations in response to mental tasks for a group of healthy control (HC, n=14) and TBI (n=29). Participants responded to an action complexity judgment task (evaluating the complexity of daily life activities by classifying the number of steps as "few" or "many") with a varying degree of cognitive load to produce brain activation. During the task, we measured blood variations with fNIRS and analyzed OV Index changes. Mean OV indices, corresponding to high complexity tasks, are higher than that of low complexity tasks in the HC group, revealing strong parametric effect (0.039±0.017 for low, 0.057±0.036 for high, p-value=0.069). However, no significant difference has been recorded for the OV indexes for two different loads in the TBI group (0.055±0.033 for low, 0.054±0.035 for high, p=0.9). OV index metrics proves to be sensitive to chronic TBI and can potentially be used to separate subpopulations TBI vs. HC. Noticeable differences in OV index spatial distributions between subpopulations have been observed. PMID:26996413

  2. Noninvasive method of estimating human newborn regional cerebral blood flow

    SciTech Connect

    Younkin, D.P.; Reivich, M.; Jaggi, J.; Obrist, W.; Delivoria-Papadopoulos, M.

    1982-12-01

    A noninvasive method of estimating regional cerebral blood flow (rCBF) in premature and full-term babies has been developed. Based on a modification of the /sup 133/Xe inhalation rCBF technique, this method uses eight extracranial NaI scintillation detectors and an i.v. bolus injection of /sup 133/Xe (approximately 0.5 mCi/kg). Arterial xenon concentration was estimated with an external chest detector. Cerebral blood flow was measured in 15 healthy, neurologically normal premature infants. Using Obrist's method of two-compartment analysis, normal values were calculated for flow in both compartments, relative weight and fractional flow in the first compartment (gray matter), initial slope of gray matter blood flow, mean cerebral blood flow, and initial slope index of mean cerebral blood flow. The application of this technique to newborns, its relative advantages, and its potential uses are discussed.

  3. Regional cerebral blood flow in childhood headache

    SciTech Connect

    Roach, E.S.; Stump, D.A.

    1989-06-01

    Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical.

  4. Hemodilution increases cerebral blood flow in acute ischemic stroke

    SciTech Connect

    Vorstrup, S.; Andersen, A.; Juhler, M.; Brun, B.; Boysen, G.

    1989-07-01

    We measured cerebral blood flow in 10 consecutive, but selected, patients with acute ischemic stroke (less than 48 hours after onset) before and after hemodilution. Cerebral blood flow was measured by xenon-133 inhalation and emission tomography, and only patients with focal hypoperfusion in clinically relevant areas were included. Hemodilution was done according to the hematocrit level: for a hematocrit greater than or equal to 42%, 500 ml whole blood was drawn and replaced by the same volume of dextran 40; for a hematocrit between 37% and 42%, only 250 ml whole blood was drawn and replaced by 500 cc of dextran 40. Mean hematocrit was reduced by 16%, from 46 +/- 5% (SD) to 39 +/- 5% (SD) (p less than 0.001). Cerebral blood flow increased in both hemispheres by an average of 20.9% (p less than 0.001). Regional cerebral blood flow increased in the ischemic areas in all cases, on an average of 21.4 +/- 12.0% (SD) (p less than 0.001). In three patients, a significant redistribution of flow in favor of the hypoperfused areas was observed, and in six patients, the fractional cerebral blood flow increase in the hypoperfused areas was of the same magnitude as in the remainder of the brain. In the last patient, cerebral blood flow increased relatively less in the ischemic areas. Our findings show that cerebral blood flow increases in the ischemic areas after hemodilution therapy in stroke patients. The marked regional cerebral blood flow increase seen in some patients could imply an improved oxygen delivery to the ischemic tissue.

  5. Effects of mild exercise on cytokines and cerebral blood flow in chronic fatigue syndrome patients.

    PubMed

    Peterson, P K; Sirr, S A; Grammith, F C; Schenck, C H; Pheley, A M; Hu, S; Chao, C C

    1994-03-01

    Chronic fatigue syndrome (CFS) is an idiopathic disorder characterized by fatigue that is markedly exacerbated by physical exertion. In the present study, we tested the hypothesis that mild exercise (walking 1 mph [1 mile = 1.609 km] for 30 min) would provoke serum cytokine and cerebral blood flow abnormalities of potential pathogenic importance in CFS. Interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha were nondetectable in sera of CFS patients (n = 10) and healthy control subjects (n = 10) pre- and postexercise. At rest, serum transforming growth factor beta (TGF-beta) levels were elevated in the CFS group compared with the control group (287 +/- 18 versus 115 +/- 5 pg/ml, respectively; P < 0.01). Serum TGF-beta and cerebral blood flow abnormalities, detected by single-photon emission-computed tomographic scanning, were accentuated postexercise in the CFS group. Although these findings were not significantly different from those in the control group, the effect of exercise on serum TGF-beta and cerebral blood flow appeared magnified in the CFS patients. Results of this study encourage future research on the interaction of physical exertion, serum cytokines, and cerebral blood flow in CFS that will adopt a more rigorous exercise program than the one used in this study. PMID:7496949

  6. Cerebral Blood Flow, Heart Rate, and Blood Pressure Patterns during the Tilt Test in Common Orthostatic Syndromes.

    PubMed

    Novak, Peter

    2016-01-01

    Objective. The head-up tilt test is widely used for evaluation of orthostatic intolerance. Although orthostatic symptoms usually reflect cerebral hypoperfusion, the cerebral blood flow velocity (CBFv) profile in orthostatic syndromes is not well described. This study evaluated CBFv and cardiovascular patterns associated with the tilt test in common orthostatic syndromes. Methods. This retrospective study analyzed the tilt test of patients with history of orthostatic intolerance. The following signals were recorded: ECG, blood pressure, CBFv using transcranial Doppler, respiratory signals, and end tidal CO2. Results. Data from 744 patients were analyzed. Characteristic pattern associated with a particular orthostatic syndrome can be grouped into abnormalities predominantly affecting blood pressure (orthostatic hypotension, orthostatic hypertension syndrome, vasomotor oscillations, and neurally mediated syncope-cardioinhibitory, vasodepressor, and mixed), cerebral blood flow (orthostatic hypoperfusion syndrome, primary cerebral autoregulatory failure), and heart rate (tachycardia syndromes: postural tachycardia syndrome, paroxysmal sinus tachycardia, and inappropriate sinus tachycardia). Psychogenic pseudosyncope is associated with stable CBFv. Conclusions. The tilt test is useful add-on in diagnosis of several orthostatic syndromes. However diagnostic criteria for several syndromes had to be modified to allow unambiguous pattern classification. CBFv monitoring in addition to blood pressure and heart rate may increase diagnostic yield of the tilt test. PMID:27525257

  7. Cerebral Blood Flow, Heart Rate, and Blood Pressure Patterns during the Tilt Test in Common Orthostatic Syndromes

    PubMed Central

    2016-01-01

    Objective. The head-up tilt test is widely used for evaluation of orthostatic intolerance. Although orthostatic symptoms usually reflect cerebral hypoperfusion, the cerebral blood flow velocity (CBFv) profile in orthostatic syndromes is not well described. This study evaluated CBFv and cardiovascular patterns associated with the tilt test in common orthostatic syndromes. Methods. This retrospective study analyzed the tilt test of patients with history of orthostatic intolerance. The following signals were recorded: ECG, blood pressure, CBFv using transcranial Doppler, respiratory signals, and end tidal CO2. Results. Data from 744 patients were analyzed. Characteristic pattern associated with a particular orthostatic syndrome can be grouped into abnormalities predominantly affecting blood pressure (orthostatic hypotension, orthostatic hypertension syndrome, vasomotor oscillations, and neurally mediated syncope—cardioinhibitory, vasodepressor, and mixed), cerebral blood flow (orthostatic hypoperfusion syndrome, primary cerebral autoregulatory failure), and heart rate (tachycardia syndromes: postural tachycardia syndrome, paroxysmal sinus tachycardia, and inappropriate sinus tachycardia). Psychogenic pseudosyncope is associated with stable CBFv. Conclusions. The tilt test is useful add-on in diagnosis of several orthostatic syndromes. However diagnostic criteria for several syndromes had to be modified to allow unambiguous pattern classification. CBFv monitoring in addition to blood pressure and heart rate may increase diagnostic yield of the tilt test. PMID:27525257

  8. Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report

    SciTech Connect

    Di Piero, V.; Perani, D.; Savi, A.; Gerundini, P.; Lenzi, G.L.; Fazio, F.

    1986-06-01

    Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-(123I)iodobenzyl-1, 3-propanediamine-2 HCl- and /sup 99m/TC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.

  9. Altered Cerebral Blood Flow Covariance Network in Schizophrenia

    PubMed Central

    Liu, Feng; Zhuo, Chuanjun; Yu, Chunshui

    2016-01-01

    Many studies have shown abnormal cerebral blood flow (CBF) in schizophrenia; however, it remains unclear how topological properties of CBF network are altered in this disorder. Here, arterial spin labeling (ASL) MRI was employed to measure resting-state CBF in 96 schizophrenia patients and 91 healthy controls. CBF covariance network of each group was constructed by calculating across-subject CBF covariance between 90 brain regions. Graph theory was used to compare intergroup differences in global and nodal topological measures of the network. Both schizophrenia patients and healthy controls had small-world topology in CBF covariance networks, implying an optimal balance between functional segregation and integration. Compared with healthy controls, schizophrenia patients showed reduced small-worldness, normalized clustering coefficient and local efficiency of the network, suggesting a shift toward randomized network topology in schizophrenia. Furthermore, schizophrenia patients exhibited altered nodal centrality in the perceptual-, affective-, language-, and spatial-related regions, indicating functional disturbance of these systems in schizophrenia. This study demonstrated for the first time that schizophrenia patients have disrupted topological properties in CBF covariance network, which provides a new perspective (efficiency of blood flow distribution between brain regions) for understanding neural mechanisms of schizophrenia. PMID:27445677

  10. Altered Cerebral Blood Flow Covariance Network in Schizophrenia.

    PubMed

    Liu, Feng; Zhuo, Chuanjun; Yu, Chunshui

    2016-01-01

    Many studies have shown abnormal cerebral blood flow (CBF) in schizophrenia; however, it remains unclear how topological properties of CBF network are altered in this disorder. Here, arterial spin labeling (ASL) MRI was employed to measure resting-state CBF in 96 schizophrenia patients and 91 healthy controls. CBF covariance network of each group was constructed by calculating across-subject CBF covariance between 90 brain regions. Graph theory was used to compare intergroup differences in global and nodal topological measures of the network. Both schizophrenia patients and healthy controls had small-world topology in CBF covariance networks, implying an optimal balance between functional segregation and integration. Compared with healthy controls, schizophrenia patients showed reduced small-worldness, normalized clustering coefficient and local efficiency of the network, suggesting a shift toward randomized network topology in schizophrenia. Furthermore, schizophrenia patients exhibited altered nodal centrality in the perceptual-, affective-, language-, and spatial-related regions, indicating functional disturbance of these systems in schizophrenia. This study demonstrated for the first time that schizophrenia patients have disrupted topological properties in CBF covariance network, which provides a new perspective (efficiency of blood flow distribution between brain regions) for understanding neural mechanisms of schizophrenia. PMID:27445677

  11. Autoregulation of cerebral blood circulation under orthostatic tests

    NASA Technical Reports Server (NTRS)

    Gayevyy, M. D.; Maltsev, V. G.; Pogorelyy, V. E.

    1980-01-01

    Autoregulation of cerebral blood flow (ACBF) under orthostatic tests (OT) was estimated in acute experiments on rabbits and cats under local anesthesia according to changes of perfusion pressure (PP) in carotid arteries, cerebral blood flow, pressure in the venous system of the brain, and resistance of cerebral vessels. The OT were conducted by turning a special table with the animal fastened to it from a horizontal to a vertical (head up or head down) position at 40 to 80 deg. In most experiments ACBF correlated with the changes of PP. Different variations of ACBF and its possible mechanisms are discussed.

  12. Cerebral blood flow velocity underestimates cerebral blood flow during modest hypercapnia and hypocapnia.

    PubMed

    Coverdale, Nicole S; Gati, Joseph S; Opalevych, Oksana; Perrotta, Amanda; Shoemaker, J Kevin

    2014-11-15

    To establish the accuracy of transcranial Doppler ultrasound (TCD) measures of middle cerebral artery (MCA) cerebral blood flow velocity (CBFV) as a surrogate of cerebral blood flow (CBF) during hypercapnia (HC) and hypocapnia (HO), we examined whether the cross-sectional area (CSA) of the MCA changed during HC or HO and whether TCD-based estimates of CBFV were equivalent to estimates from phase contrast (PC) magnetic resonance imaging. MCA CSA was measured from 3T magnetic resonance images during baseline, HO (hyperventilation at 30 breaths/min), and HC (6% carbon dioxide). PC and TCD measures of CBFV were measured during these protocols on separate days. CSA and TCD CBFV were used to calculate CBF. During HC, CSA increased from 5.6 ± 0.8 to 6.5 ± 1.0 mm(2) (P < 0.001, n = 13), while end-tidal carbon dioxide partial pressure (PETCO2) increased from 37 ± 3 to 46 ± 5 Torr (P < 0.001). During HO, CSA decreased from 5.8 ± 0.9 to 5.3 ± 0.9 mm(2) (P < 0.001, n = 15), while PetCO2 decreased from 36 ± 4 to 23 ± 3 Torr (P < 0.001). CBFVs during baseline, HO, and HC were compared between PC and TCD, and the intraclass correlation coefficient was 0.83 (P < 0.001). The relative increase from baseline was 18 ± 8% greater (P < 0.001) for CBF than TCD CBFV during HC, and the relative decrease of CBF during HO was 7 ± 4% greater than the change in TCD CBFV (P < 0.001). These findings challenge the assumption that the CSA of the MCA does not change over modest changes in PETCO2. PMID:25012027

  13. Mathematical Modelling of Cerebral Blood Circulation and Cerebral Autoregulation: Towards Preventing Intracranial Hemorrhages in Preterm Newborns

    PubMed Central

    Botkin, Nikolai; Alves-Pinto, Ana

    2014-01-01

    Impaired cerebral autoregulation leads to fluctuations in cerebral blood flow, which can be especially dangerous for immature brain of preterm newborns. In this paper, two mathematical models of cerebral autoregulation are discussed. The first one is an enhancement of a vascular model proposed by Piechnik et al. We extend this model by adding a polynomial dependence of the vascular radius on the arterial blood pressure and adjusting the polynomial coefficients to experimental data to gain the autoregulation behavior. Moreover, the inclusion of a Preisach hysteresis operator, simulating a hysteretic dependence of the cerebral blood flow on the arterial pressure, is tested. The second model couples the blood vessel system model by Piechnik et al. with an ordinary differential equation model of cerebral autoregulation by Ursino and Lodi. An optimal control setting is proposed for a simplified variant of this coupled model. The objective of the control is the maintenance of the autoregulatory function for a wider range of the arterial pressure. The control can be interpreted as the effect of a medicament changing the cerebral blood flow by, for example, dilation of blood vessels. Advanced numerical methods developed by the authors are applied for the numerical treatment of the control problem. PMID:25126111

  14. Frequency and patterns of abnormality detected by iodine-123 amine emission CT after cerebral infarction

    SciTech Connect

    Brott, T.G.; Gelfand, M.J.; Williams, C.C.; Spilker, J.A.; Hertzberg, V.S.

    1986-03-01

    Single photon emission computed tomography (SPECT) was performed in 31 patients with cerebral infarction and 13 who had had transient ischemic attacks, using iodine-123-labeled N,N,N'-trimethyl-N'-(2-hydroxyl-3-methyl-5-iodobenzyl)-1,3-propanediamin e (I-123-HIPDM) as the radiopharmaceutical. SPECT scans were compared with computed tomographic (CT) scans. SPECT was as sensitive as CT in detecting cerebral infarction (94% vs. 84%). The abnormalities were larger on the SPECT scans than on the CT scans in 19 cases, equal in seven, and smaller in five (SPECT abnormalities greater than or equal to CT abnormalities in 86% of cases). Fifteen of 30 patients with hemispheric infarction had decreased perfusion (decreased uptake of I-123-HIPDM) to the cerebellar hemisphere contralateral to the cerebral hemisphere involved by the infarction (crossed cerebellar diaschisis). Nine of these 15 patients had major motor deficits, while only one of the 15 without crossed cerebellar diaschisis had a major motor deficit.

  15. Cerebral blood flow in the newborn infant.

    PubMed Central

    Pryds, O.; Edwards, A. D.

    1996-01-01

    Studies of CBF have provided some insight into cerebrovascular physiology and pharmacology. However, the precise relation between CBF and cerebral damage remains elusive, and there is no definition of a threshold CBF below which ischaemic brain damage always occurs. Measurement of CBF thus does not currently provide a secure guide in the clinical management of sick infants. Further work, particularly using techniques like magnetic resonance imaging and NIRS, which provide data in addition to CBF measurements, may yet disclose strategies which manipulate CBF to reduce cerebral ischaemia. While cerebral injury remains a substantial problem in neonatal intensive care, such research is urgently needed. Images Figure 3 PMID:8653440

  16. Abnormal cerebral effective connectivity during explicit emotional processing in adults with autism spectrum disorder

    PubMed Central

    Fonlupt, Pierre; Hubert, Bénédicte; Tardif, Carole; Gepner, Bruno; Deruelle, Christine

    2008-01-01

    Several recent studies suggest that autism may result from abnormal communication between brain regions. We directly assessed this hypothesis by testing the presence of abnormalities in a model of the functional cerebral network engaged during explicit emotion processing in adults with high functioning autism or Asperger syndrome. Comparison of structural equation models revealed abnormal patterns of effective connectivity, with the prefrontal cortex as a key site of dysfunction. These findings provide evidence that abnormal long-range connectivity between structures of the ‘social brain’ could explain the socio-emotional troubles that characterize the autistic pathology. PMID:19015104

  17. Cerebral blood flow: Physiologic and clinical aspects

    SciTech Connect

    Wood, J.H.

    1987-01-01

    This book contains 46 chapters divided among nine sections. The section titles are: Historical Perspectives; Cerebrovascular Anatomy; Cerebrovascular Physiology; Methods of Clinical Measurement; Experimental Methods; Imaging of Cerebral Circulation; Cerebrovascular Pathophysiology; Cerebrovascular Pharmacology; and Surgical and Interventional Augmentation.

  18. Cerebral blood flow measured by NMR indicator dilution in cats

    SciTech Connect

    Ewing, J.R.; Branch, C.A.; Helpern, J.A.; Smith, M.B.; Butt, S.M.; Welch, K.M.

    1989-02-01

    We developed techniques to assess the utility of a nuclear magnetic resonance (NMR) indicator for cerebral blood flow studies in cats, using Freon-22 for the first candidate. A PIN-diode-switched NMR experiment allowed the acquisition of an arterial as well as a cerebral fluorine-19 signal proportional to concentration vs. time in a 1.89 T magnet. Mean +/- SD blood:brain partition coefficients for Freon-22 were estimated at 0.93 +/- 0.08 for gray matter and 0.77 +/- 0.12 for white matter. Using maximum-likelihood curve fitting, estimates of mean +/- SD resting cerebral blood flow were 50 +/- 19 ml/100 g-min for gray matter and 5.0 +/- 2.0 ml/100 g-min for white matter. Hypercapnia produced the expected increases in gray and white matter blood flow. The physiologic effects of Freon-22, including an increase in cerebral blood flow itself with administration of 40% by volume, may limit its use as an indicator. Nevertheless, the NMR techniques described demonstrate the feasibility of fluorine-19-labeled compounds as cerebral blood flow indicators and the promise for their use in humans.

  19. Cerebral abnormalities: use of calculated T1 and T2 magnetic resonance images for diagnosis

    SciTech Connect

    Mills, C.M.; Crooks, L.E.; Kaufman, L.; Brant-Zawadzki, M.

    1984-01-01

    The potential clinical importance of T1 and T2 relaxation times in distinguishing normal and pathologic tissue with magnetic resonance (MR) is discussed and clinical examples of cerebral abnormalities are given. Five patients with cerebral infarction, 15 with multiple sclerosis, two with Wilson disease, and four with tumors were imaged. Hemorrhagic and ischemic cerebrovascular accidents were distinguished using the spin echo technique. In the patients with multiple sclerosis, lesions had prolonged T1 and T2 times, but the definition of plaque was limited by spatial resolution. No abnormalities in signal intensity were seen in the patient with Wilson disease who was no longer severly disabled; abnormal increased signal intensity in the basal ganglia was found in the second patient with Wilson disease. Four tumors produced abnormal T1 and T2 relaxation times but these values alone were not sufficient for tumor characterization.

  20. Cerebral blood flow and autoregulation during hypothermic cardiopulmonary bypass

    SciTech Connect

    Johnsson, P.; Messeter, K.; Ryding, E.; Nordstroem, L.S.; Stahl, E.

    1987-04-01

    Mean hemispheric cerebral blood flow (CBF) was studied following intravenous or intraarterial administration of xenon-133, in 10 men admitted for coronary artery bypass grafting. Repeated CBF measurements were performed to evaluate autoregulation before, during, and after cardiopulmonary bypass (CPB). During CPB mean CBF remained unchanged compared with the pre-CPB level, without evidence of cerebral hyperemia or impairment of autoregulation. A marked increase in CBF occurred after CPB and was followed by a time-dependent reduction toward the pre-CPB level. The data support the alpha-stat regulation theory but cannot explain the cerebral vasodilation observed after CPB.

  1. Cerebral Blood Flow Autoregulation and Dysautoregulation.

    PubMed

    Armstead, William M

    2016-09-01

    This article provides a review of cerebral autoregulation, particularly as it relates to the clinician scientist experienced in neuroscience in anesthesia and critical care. Topics covered are biological mechanisms; methods used for assessment of autoregulation; effects of anesthetics; role in control of cerebral hemodynamics in health and disease; and emerging areas, such as role of age and sex in contribution to dysautoregulation. Emphasis is placed on bidirectional translational research wherein the clinical informs the study design of basic science studies, which, in turn, informs the clinical to result in development of improved therapies for treatment of central nervous system conditions. PMID:27521192

  2. Regional cerebral blood flow in mood disorders. I. Comparison of major depressives and normal controls at rest

    SciTech Connect

    Sackeim, H.A.; Prohovnik, I.; Moeller, J.R.; Brown, R.P.; Apter, S.; Prudic, J.; Devanand, D.P.; Mukherjee, S. )

    1990-01-01

    We measured regional cerebral blood flow with the xenon 133 inhalation technique in 41 patients with major depressive disorder and 40 matched, normal controls during an eyes-closed, resting condition. The depressed group had a marked reduction in global cortical blood flow. To examine topographic abnormalities, traditional multivariate analyses were applied, as well as a new scaled subprofile model developed to identify abnormal functional neural networks in clinical samples. Both approaches indicated that the depressed sample had an abnormality in topographic distribution of blood flow, in addition to the global deficit. The scaled subprofile model identified the topographic abnormality as being due to flow reduction in the depressed patients in selective frontal, central, superior temporal, and anterior parietal regions. This pattern may reflect dysfunction in the parallel distributed cortical network involving frontal and temporoparietal polymodal association areas. The extent of this topographic abnormality, as revealed by the scaled subprofile model, was associated with both patient age and severity of depressive symptoms.

  3. Hypothermia reduces cerebral metabolic rate and cerebral blood flow in newborn pigs

    SciTech Connect

    Busija, D.W.; Leffler, C.W. )

    1987-10-01

    The authors examined effects of hypothermia on cerebral metabolic rate and cerebral blood flow in anesthetized, newborn pigs (1-4 days old). Cerebral blood flow (CBF) was determined with 15-{mu}m radioactive microspheres. Regional CBF ranged from 44 to 66 ml{center dot}min{sup {minus}1}{center dot}100 g{sup {minus}1}, and cerebral metabolic rate was 1.94 {plus minus} 0.23 ml O{sub 2}{center dot}100 g{sup {minus}1}{center dot}min{sup {minus}1} during normothermia (39{degree}C). Reduction of rectal temperature to 34-35{degree}C decreased CBF and cerebral metabolic rate 40-50%. In another group of piglets, they examined responsiveness of the cerebral circulation to arterial hypercapnia during hypothermia. Although absolute values for normocapnic and hypercapnic CBF were reduced by hypothermia and absolute values for normocapnic and hypercapnic cerebrovascular resistance were increased, the percentage changes from control in these variables during hypercapnia were similar during normothermia and hypothermia. In another group of animals that were maintained normothermic and exposed to two episodes of hypercapnia, there was no attenuation of cerebrovascular dilation during the second episode. They conclude that hypothermia reduces CBF secondarily to a decrease in cerebral metabolic rate and that percent dilator responsiveness to arterial hypercapnia is unaltered when body temperature is reduced.

  4. Modelling cerebral blood oxygenation using Monte Carlo XYZ-PA

    NASA Astrophysics Data System (ADS)

    Zam, Azhar; Jacques, Steven L.; Alexandrov, Sergey; Li, Youzhi; Leahy, Martin J.

    2013-02-01

    Continuous monitoring of cerebral blood oxygenation is critically important for the management of many lifethreatening conditions. Non-invasive monitoring of cerebral blood oxygenation with a photoacoustic technique offers advantages over current invasive and non-invasive methods. We introduce a Monte Carlo XYZ-PA to model the energy deposition in 3D and the time-resolved pressures and velocity potential based on the energy absorbed by the biological tissue. This paper outlines the benefits of using Monte Carlo XYZ-PA for optimization of photoacoustic measurement and imaging. To the best of our knowledge this is the first fully integrated tool for photoacoustic modelling.

  5. Regional cerebral blood flow characteristics of the Sturge-Weber syndrome

    SciTech Connect

    Riela, A.R.; Stump, D.A.; Roach, E.S.; McLean, W.T. Jr.; Garcia, J.C.

    1985-03-01

    Four patients with the Sturge-Weber syndrome were studied using the non-invasive Xenon-133 inhalation technique. All four patients had decreased regional cerebral blood flow in the area of their lesion, and in two patients who were subsequently tested with 5% carbon dioxide inhalation, impaired vasomotor reactivity was documented. Diminished regional cerebral blood flow is consistent with previously described nuclide flow studies which demonstrated a delay in the initial perfusion blush in the region of the abnormal vasculature. The focal decrease in blood flow was greatest in the most severely affected patient, but was also prominent in the two younger patients, both of whom have excellent neurologic function. These studies suggest that localized decrease in blood flow and vasomotor dysfunction in Sturge-Weber syndrome can precede the occurrence of severe neurologic impairment and extensive cerebral atrophy and possibly be a major contributing factor in progressive dysfunction. A secondary observation was that the blood flow in the unaffected hemisphere was significantly greater in two children compared to the two adults and was similar to the age-related differences reported for normal children and adults.

  6. Local cerebral blood flow and partition coefficients measured in cerebral astrocytomas of different grades of malignancy

    SciTech Connect

    Tachibana, H.; Meyer, J.S.; Rose, J.E.; Kandula, P.

    1984-02-01

    Local cerebral blood flow and local partition coefficients were measured in patients with different grades of malignant cerebral astrocytomas (n . 5) who inhaled 35% stable xenon during computed tomography scanning. Results were compared with those in age-matched normal subjects (n . 5. Mean values for local cerebral blood flow in the gray matter in patients with astrocytomas were decreased throughout the tumor mass and surrounding brain that was apparently free of tumor. Patients with highly malignant glioblastoma multiforme (astrocytoma grade IV; n . 2) showed more variable values for local cerebral blood flow and local partition coefficients compared to those with astrocytomas of lower grades (grades I-II; n . 3). Local partition coefficients in gray matter invaded by grade IV astrocytoma were significantly higher than those in gray matter invaded by grade I-III astrocytomas. Local cerebral blood flow and local partition coefficients in the brain tissue surrounding grade IV astrocytomas were reduced to a greater extent than those in more benign tumors.

  7. Abnormal catecholamine urinary excretion after emotional stimulus in patients with cerebral hemorrhage.

    PubMed

    Stoica, E; Enulescu, O

    1981-01-01

    The epinephrine (E) and norepinephrine (NE) urinary excretion before and after a mild "emotional stimulus" (ES) was determined in 22 patients with cerebral infarction and 30 patients with cerebral hemorrhage, as well as in 18 normotensive and 18 hypertensive controls. In patients with cerebral infarction, the majority normotensive, the "emotional stimulus" induced a significant increase in NE excretion, but non-significant alterations in E excretion. Similar changes were noted in normotensive controls. In patients with cerebral hemorrhage, almost all hypertensive, and in hypertensive controls, ES brought about a consistent rise in E excretion without influencing significantly the NE excretion. The presence of a constant increase in E excretion after a mild emotion not only in patients with cerebral hemorrhage but also in subjects with uncomplicated essential hypertension, suggests that the E release found in patients with cerebral hemorrhage is related to the hypertensive state pre-existing the stroke rather than to hemorrhagic stroke itself. The pattern of catecholamine discharge in hypertensive patients might play a part in the occurrence of cerebral hemorrhagic accidents. The epinephrine discharges induce sudden increases in systolic blood pressure which could lead to the rupture of cerebral vessels with hyalinotic or atherosclerotic alterations. PMID:7245303

  8. Role of phorbol esters in regional cerebral blood flow regulation

    SciTech Connect

    Hanley, D.F.; Uhl, G.R.; Miyabe, M.; Traystman, R.J.

    1986-03-05

    Phorbol esters are known to activate protein kinase C, an intracellular enzyme capable of phosphorylating membrane associated receptors. By using phorbol-12-13-dibutyrate (PDBU), they investigated the presence and function of protein kinase C on canine cerebral vessels. In vitro tissue autoradiographic studies performed on 8 ..mu.. sections of canine cerebral vessels with H/sup 3/-PDBU revealed a 3 to 1 ratio of specific to nonspecific binding. Competitive displacement was demonstrated for 3 physiologically active phorbol esters but could not be demonstrated for 3 physiologically inactive phorbol derivatives. The effect of PDBU on regional cerebral blood flow (rCBF) was then studied in vivo using radiolabelled microspheres in 6 dogs. Measurements were made during control ventriculocisternal CSF infusions and 5,10,15,20 and 25 minutes after infusion of .1 nM/min PDBU. For grey matter regions in contact with the perfusate, caudate nucleus, cortical watershed and cerebellum, blood flow increased from 33 +/- 6 to 45 +/- 7, 20 +/- 2 to 27 +/- 2, and 31 +/- 2 to 42 +/- 5 ml/min/100 gm, respectively. rCBF was unchanged for brainstem, temporal lobe or white matter regions. They conclude (1) PDBU has high affinity binding to canine cerebral vascular smooth muscle, and (2) PDBU produces an increase in rCBF when delivered intraventricularly. These data suggest a possible role for protein kinase C in the regulation of cerebral blood flow.

  9. The effect of ventricular assist devices on cerebral blood flow and blood pressure fractality.

    PubMed

    Bellapart, Judith; Chan, Gregory S H; Tzeng, Yu-Chieh; Ainslie, Philip N; Dunster, Kimble R; Barnett, Adrian G; Boots, Rob; Fraser, John F

    2011-09-01

    Biological signals often exhibit self-similar or fractal scaling characteristics which may reflect intrinsic adaptability to their underlying physiological system. This study analysed fractal dynamics of cerebral blood flow in patients supported with ventricular assist devices (VAD) to ascertain if sustained modifications of blood pressure waveform affect cerebral blood flow fractality. Simultaneous recordings of arterial blood pressure and cerebral blood flow velocity using transcranial Doppler were obtained from five cardiogenic shock patients supported by VAD, five matched control patients and five healthy subjects. Computation of a fractal scaling exponent (α) at the low-frequency time scale by detrended fluctuation analysis showed that cerebral blood flow velocity exhibited 1/f fractal scaling in both patient groups (α = 0.95 ± 0.09 and 0.97 ± 0.12, respectively) as well as in the healthy subjects (α = 0.86 ± 0.07). In contrast, fluctuation in blood pressure was similar to non-fractal white noise in both patient groups (α = 0.53 ± 0.11 and 0.52 ± 0.09, respectively) but exhibited 1/f scaling in the healthy subjects (α = 0.87 ± 0.04, P < 0.05 compared with the patient groups). The preservation of fractality in cerebral blood flow of VAD patients suggests that normal cardiac pulsation and central perfusion pressure changes are not the integral sources of cerebral blood flow fractality and that intrinsic vascular properties such as cerebral autoregulation may be involved. However, there is a clear difference in the fractal scaling properties of arterial blood pressure between the cardiogenic shock patients and the healthy subjects. PMID:21775798

  10. Trigeminal neuralgia increases cerebral blood flow in a focal cerebral ischemic model in rats

    PubMed Central

    Wang, Wei; Zhao, Weiliang; Liu, Zhenxiu; Xia, Jianhua; Wu, Jingru; Shi, Xueyin

    2015-01-01

    Objective: To investigate the influences of trigeminal neuropathic pain on the cerebral blood flow in a ET-1 focal cerebral ischemia model. Methods: Male Sprague-Dawley (SD) rats (220-260 g) were randomly divided into a model group (trigeminal neuralgia, TN group) and a sham operation group (sham group). The TN group received bilateral infraorbital nerve chronic constriction surgery, and the sham group only underwent exposure of the infraorbital nerve. The mechanical pain threshold of the rats was continuously monitored for 30 days post surgery. On postoperative day 30, the animals were anesthetized, and 3 μL (120 pM/μL) ET-1 was injected into the surroundings of the middle cerebral artery (MCA) to establish a cerebral focal ischemia-reperfusion injury model in rats. The changes in cerebral blood flow of these two groups were monitored 30 min after the injection of ET-1. Results: The mechanic pain threshold values between rats in the two groups were not significantly different (P>0.05). The threshold value in the TN group on postoperative day 9 significantly decreased compared with that before surgery (P<0.01). Between postoperative days 9 and 30, the pain threshold values in the TN group were significantly lower than those in the sham group (P<0.01). From postoperative day 10, the mean arterial pressure in the TN group significantly increased compared with that before surgery (P<0.05), and the blood pressure (BP) in the TN group was higher than that in the sham group between postoperative days 10 and 30 (P<0.05). After 75 min of ET-1 microinjection, the cerebral blood flow in the rat frontal cortex exhibited reperfusion, and the cerebral blood flow in the TN group was significantly higher than that in the sham group (P<0.05). In addition, the content of calcitonin gene-related peptide (CGRP) in the blood of rats in the TN group was significantly higher than that in the sham group (P<0.05). Conclusions: Trigeminal neuropathic pain may increase the mean arterial

  11. Longitudinal Cerebral Blood Flow Changes during Speech in Hereditary Ataxia

    ERIC Educational Resources Information Center

    Sidtis, John J.; Strother, Stephen C.; Naoum, Ansam; Rottenberg, David A.; Gomez, Christopher

    2010-01-01

    The hereditary ataxias constitute a group of degenerative diseases that progress over years or decades. With principal pathology involving the cerebellum, dysarthria is an early feature of many of the ataxias. Positron emission tomography was used to study regional cerebral blood flow changes during speech production over a 21 month period in a…

  12. [Changes of cerebral blood flow during diving reactions in humans].

    PubMed

    Baranova, T I; Berlov, D N; Ianvareva, I N

    2014-05-01

    The characteristics of human cerebral blood flow were estimated during the implementation of the diving response, simulated by complex cold-hypoxic-hypercapnic exposure (CHHE), and under the influence of separate cold, hypercapnic and hypoxic stimuli. Was studied 18 people aged 18-22 years who had no special training. Cerebral blood flow was recorded by transcranial Doppler. It is shown that in the CHHE with the respect initial state to observe a marked increase in cerebral blood flow linear velocity (BFV) to 82.3 ± 15.2%, as well as reducing characterizing the tone of resistance vessels of the brain pulsatility index (PI) to 77.2 ± 13.1%. During cold and tactile stimulation of facial skin BFV and PI did not change significantly, with a single breath hold (Genchi test) BFV increased by 52.3 ± 12.5%, PI at 64.5 ± 15%. The latent period of cerebral blood flow (14-43) allow suppose metabolic (chemical) nature of regulatory influences, which provide changes of considered indicators. PMID:25669101

  13. Ozone Therapy on Cerebral Blood Flow: A Preliminary Report

    PubMed Central

    2004-01-01

    Ozone therapy is currently being used in the treatment of ischemic disorders, but the underlying mechanisms that result in successful treatment are not well known. This study assesses the effect of ozone therapy on the blood flow in the middle cerebral and common carotid arteries. Seven subjects were recruited for the therapy that was performed by transfusing ozone-enriched autologous blood on 3 alternate days over 1 week. Blood flow quantification in the common carotid artery (n = 14) was performed using color Doppler. Systolic and diastolic velocities in the middle cerebral artery (n = 14) were estimated using transcranial Doppler. Ultrasound assessments were conducted at the following three time points: 1) basal (before ozone therapy), 2) after session #3 and 3) 1 week after session #3. The common carotid blood flow had increased by 75% in relation to the baseline after session #3 (P < 0.001) and by 29% 1 week later (P = 0.039). In the middle cerebral artery, the systolic velocity had increased by 22% after session #3 (P = 0.001) and by 15% 1 week later (P = 0.035), whereas the diastolic velocity had increased by 33% after session #3 (P < 0.001) and by 18% 1 week later (P = 0.023). This preliminary Doppler study supports the clinical experience of achieving improvement by using ozone therapy in peripheral ischemic syndromes. Its potential use as a complementary treatment in cerebral low perfusion syndromes merits further clinical evaluation. PMID:15841265

  14. Cerebral oxygen metabolism and blood flow in human cerebral ischemic infarction

    SciTech Connect

    Lenzi, G.L.; Frackowiak, R.S.; Jones, T.

    1982-09-01

    Fifteen patients with acute cerebral hemispheric infarcts have been studied with positron emission tomography and the /sup 15/O steady-state inhalation technique. Thirteen follow-up studies were also performed. The values of cerebral oxygen metabolism (CMRO/sub 2/), cerebral blood flow (CBF), and oxygen extraction ration (OER) have been calculated for the infarcted regions, their borders, the symmetrical regions in contralateral cerebral hemispheres, and the cerebellar hemispheres. This study demonstrates that in the completed stroke there are thresholds for regional CMRO/sub 2/ and regional CBF below which the general clinical outcome of the patients is usually poor. The ischaemic lesions invariably produce an uncoupling between the greatly decreased metabolic demand and the less affected blood supply, with very frequent instances of relative hyperperfusion. Remote effects of the hemispheric infarcts have been demonstrated, such as crossed cerebellar diaschisis and contralateral transhemispheric depression. The level of consciousness correlates with oxygen uptake and blood flow both in the posterior fossa and in the contralateral cerebral hemispheres. The follow-up studies of individual patients underline the high variability of metabolism-to-flow balance during the acute phase of the illness, and stress the need for more studies focused on repeated assessments of homogeneous patient populations.

  15. Increased Cerebral Blood Flow Velocity in Children with Mild Sleep-Disordered Breathing

    PubMed Central

    Hill, Catherine M.; Hogan, Alexandra M.; Onugha, Nwanneka; Harrison, Dawn; Cooper, Sara; McGrigor, Victoria J.; Datta, Avijit; Kirkham, Fenella J.

    2007-01-01

    Objective Sleep-disordered breathing describes a spectrum of upper airway obstruction in sleep from simple primary snoring, estimated to affect 10% of preschool children, to the syndrome of obstructive sleep apnea. Emerging evidence has challenged previous assumptions that primary snoring is benign. A recent report identified reduced attention and higher levels of social problems and anxiety/depressive symptoms in snoring children compared with controls. Uncertainty persists regarding clinical thresholds for medical or surgical intervention in sleep-disordered breathing, underlining the need to better understand the pathophysiology of this condition. Adults with sleep-disordered breathing have an increased risk of cerebrovascular disease independent of atherosclerotic risk factors. There has been little focus on cerebrovascular function in children with sleep-disordered breathing, although this would seem an important line of investigation, because studies have identified abnormalities of the systemic vasculature. Raised cerebral blood flow velocities on transcranial Doppler, compatible with raised blood flow and/or vascular narrowing, are associated with neuropsychological deficits in children with sickle cell disease, a condition in which sleep-disordered breathing is common. We hypothesized that there would be cerebral blood flow velocity differences in sleep-disordered breathing children without sickle cell disease that might contribute to the association with neuropsychological deficits. Design Thirty-one snoring children aged 3 to 7 years were recruited from adenotonsillectomy waiting lists, and 17 control children were identified through a local Sunday school or as siblings of cases. Children with craniofacial abnormalities, neuromuscular disorders, moderate or severe learning disabilities, chronic respiratory/cardiac conditions, or allergic rhinitis were excluded. Severity of sleep-disordered breathing in snoring children was categorized by attended

  16. Cerebral glucose utilization and blood flow in Huntington's Disease (HD)

    SciTech Connect

    Phelps, M.E.; Mazziotta, J.C.; Wapenski, J.; Riege, W.; Baxter, L.R.

    1985-05-01

    Previous studies in the authors' Laboratory have been carried out on 13 patients symptomatic of HD (SHD) and 15 asymptomatic at-risk for HD (ARHD) with a ECAT II and identification of changes in caudate metabolism using an index technique. The authors report now studies of additional 28 subjects (11 SHD, 17 ARHD) studied drug free and compared to age/sex matched controls using the higher resolution NeuroECAT, FDG for glucose utilization (LCMRGlc) and 0-15 water for cerebral blood flow (CBF). Patients had neurological, psychiatric-tests, x-ray CT and were video taped to determine type, timing and amount of choreathetic movements during study. In SHD (disease duration 4.9 +- 2.7 yrs), significant decreases (30%) in LCMRGlc were found in striatum (SHD=19.3 +- 7.7, controls = 29.9 +- 5.8 ..mu.. moles/min/100g) despite no to moderate caudate atrophy on x-ray CT. Hemisphere and cortical CMRGlc were not significantly decreased. There was a significant correlation between disease duration and ratio of caudate to putamen (Cd/Put). Pattern of LCMRGlc and CBF matched in SHD. The caudate to hemisphere LCMRGlc ratio was not different between ARHD and controls except variance was about 4 times greater for ARHD (ARHD=1.21 +- 0.15, controls = 1.28 +- 0.04) indicating presence of subpopulations in ARHD group. Four ARHD subjects had a ratio of 1 Std. Dev. from mean of SHD (no normals had values in this range). The 2 ARHD subjects with lowest caudate LCMRGlc had Cd/Put ratios > 2 Std. Dev. from controls. Results show 1) LCMRGlc abnormalities in all SHD patients and subpopulations in ARHD, 2) metabolic alterations appear to begin in caudate and spread to putamen and that a Cd/Put value of 0.7 should be found at start of symptoms, and 3) cortex and thalamus are relatively spared in ARHD and early SHD.

  17. Cerebral Blood Flow Alterations in Acute Sport-Related Concussion.

    PubMed

    Wang, Yang; Nelson, Lindsay D; LaRoche, Ashley A; Pfaller, Adam Y; Nencka, Andrew S; Koch, Kevin M; McCrea, Michael A

    2016-07-01

    Sport-related concussion (SRC) is a major health problem, affecting millions of athletes each year. While the clinical effects of SRC (e.g., symptoms and functional impairments) typically resolve within several days, increasing evidence suggests persistent neurophysiological abnormalities beyond the point of clinical recovery after injury. This study aimed to evaluate cerebral blood flow (CBF) changes in acute SRC, as measured using advanced arterial spin labeling (ASL) magnetic resonance imaging (MRI). We compared CBF maps assessed in 18 concussed football players (age, 17.8 ± 1.5 years) obtained within 24 h and at 8 days after injury with a control group of 19 matched non-concussed football players. While the control group did not show any changes in CBF between the two time-points, concussed athletes demonstrated a significant decrease in CBF at 8 days relative to within 24 h. Scores on the clinical symptom (Sport Concussion Assessment Tool 3, SCAT3) and cognitive measures (Standardized Assessment of Concussion [SAC]) demonstrated significant impairment (vs. pre-season baseline levels) at 24 h (SCAT, p < 0.0001; SAC, p < 0.01) but returned to baseline levels at 8 days. Two additional computerized neurocognitive tests, the Automated Neuropsychological Assessment Metrics and Immediate Post-Concussion and Cognitive Testing, showed a similar pattern of changes. These data support the hypothesis that physiological changes persist beyond the point of clinical recovery after SRC. Our results also indicate that advanced ASL MRI methods might be useful for detecting and tracking the longitudinal course of underlying neurophysiological recovery from concussion. PMID:26414315

  18. Cerebral blood flow links insulin resistance and baroreflex sensitivity.

    PubMed

    Ryan, John P; Sheu, Lei K; Verstynen, Timothy D; Onyewuenyi, Ikechukwu C; Gianaros, Peter J

    2013-01-01

    Insulin resistance confers risk for diabetes mellitus and associates with a reduced capacity of the arterial baroreflex to regulate blood pressure. Importantly, several brain regions that comprise the central autonomic network, which controls the baroreflex, are also sensitive to the neuromodulatory effects of insulin. However, it is unknown whether peripheral insulin resistance relates to activity within central autonomic network regions, which may in turn relate to reduced baroreflex regulation. Accordingly, we tested whether resting cerebral blood flow within central autonomic regions statistically mediated the relationship between insulin resistance and an indirect indicator of baroreflex regulation; namely, baroreflex sensitivity. Subjects were 92 community-dwelling adults free of confounding medical illnesses (48 men, 30-50 years old) who completed protocols to assess fasting insulin and glucose levels, resting baroreflex sensitivity, and resting cerebral blood flow. Baroreflex sensitivity was quantified by measuring the magnitude of spontaneous and sequential associations between beat-by-beat systolic blood pressure and heart rate changes. Individuals with greater insulin resistance, as measured by the homeostatic model assessment, exhibited reduced baroreflex sensitivity (b = -0.16, p < .05). Moreover, the relationship between insulin resistance and baroreflex sensitivity was statistically mediated by cerebral blood flow in central autonomic regions, including the insula and cingulate cortex (mediation coefficients < -0.06, p-values < .01). Activity within the central autonomic network may link insulin resistance to reduced baroreflex sensitivity. Our observations may help to characterize the neural pathways by which insulin resistance, and possibly diabetes mellitus, relates to adverse cardiovascular outcomes. PMID:24358272

  19. Impact of COPD exacerbation on cerebral blood flow.

    PubMed

    Yildiz, Sema; Kaya, Ihsan; Cece, Hasan; Gencer, Mehmet; Ziylan, Zeki; Yalcin, Funda; Turksoy, Ozlem

    2012-01-01

    We aimed to investigate the impact of chronic obstructive pulmonary disease (COPD) exacerbation on cerebral blood flow (CBF). In 21 COPD patients - in both exacerbation and stable phases -Doppler ultrasonographies of internal carotid artery (ICA) and vertebral artery (VA) were performed. There were significant differences in total, anterior and posterior CBF, ICA and VA flow volumes in exacerbated COPD compared to stable COPD. Total CBF was correlated with cross-sectional areas of left and right ICA, whereas independent predictor of total CBF was cross-sectional area of right ICA. Increased CBF might indicate cerebral autoregulation-mediated vasodilatation to overcome COPD exacerbation induced hypoxia. PMID:22542376

  20. Effects of midazolam on cerebral blood flow in human volunteers

    SciTech Connect

    Forster, A.; Juge, O.; Morel, D.

    1982-06-01

    The effects of intravenously administered midazolam on cerebral blood flow were evaluated in eight healthy volunteers using the /sup 133/Xe inhalation technique. Six minutes after an intravenous dose of 0.15 mg/kg midazolam, the cerebral blood flow decreased significantly (P less than 0.001) from a value of 40.6 +/- 3.3 to a value of 27.0 +/- 5.0 ml . 100 g-1 . min-1. Cerebrovascular resistance (CVR) increased from 2.8 +/- 0.2 to 3.9 to 0.6 mmHg/(ml . 100 g-1 . min-1)(P less than 0.001). Mean arterial blood pressure decreased significantly (P less than 0.05) from 117 +/- 8 to 109 +/- 9 mmHg and arterial carbon dioxide tension increased from 33.9 +/- 2.3 to 38.6 +/- 3.2 mmHg (P less than 0.05). Arterial oxygen tension remained stable throughout the study, 484 +/- 95 mmHg before the administration of midazolam and 453 +/- 76 mmHg after. All the subjects slept after the injection of the drug and had anterograde amnesia of 24.5 +/- 5 min. The decrease in mean arterial blood pressure was probably not important since it remained in the physiologic range for cerebral blood flow autoregulation. The increase in arterial carbon dioxide tension observed after the midazolam injection may have partially counteracted the effect of this new benzodiazepine on cerebral blood flow. Our data suggest that midazolam might be a safe agent to use for the induction of anethesia in neurosurgical patients with intracranial hypertension.

  1. Relative changes of cerebral arterial and venous blood volumes during increased cerebral blood flow: implications for BOLD fMRI.

    PubMed

    Lee, S P; Duong, T Q; Yang, G; Iadecola, C; Kim, S G

    2001-05-01

    Measurement of cerebral arterial and venous blood volumes during increased cerebral blood flow can provide important information regarding hemodynamic regulation under normal, pathological, and neuronally active conditions. In particular, the change in venous blood volume induced by neural activity is one critical component of the blood oxygenation level-dependent (BOLD) signal because BOLD contrast is dependent only on venous blood, not arterial blood. Thus, relative venous and arterial blood volume (rCBV) and cerebral blood flow (rCBF) in alpha-chlorolase-anesthetized rats under hypercapnia were measured by novel diffusion-weighted (19)F NMR following an i.v. administration of intravascular tracer, perfluorocarbons, and continuous arterial spin labeling methods, respectively. The relationship between rCBF and total rCBV during hypercapnia was rCBV(total) = rCBF(0.40), which is consistent with previous PET measurement in monkeys. This relationship can be linearized in a CBF range of 50-130 ml/100 g/min as DeltarCBV(total)/ DeltarCBF = 0.31 where DeltarCBV and DeltarCBF represent rCBV and rCBF changes. The average arterial volume fraction was 0.25 at a basal condition with CBF of approximately 60 ml/100 g/min and increased up to 0.4 during hypercapnia. The change in venous rCBV was 2-fold smaller than that of total rCBV (DeltarCBV(vein)/DeltarCBF = 0.15), while the arterial rCBV change was 2.5 times larger than that of total rCBV (DeltarCBV(artery)/DeltarCBF = 0.79). These NMR results were confirmed by vessel diameter measurements with in vivo videomicroscopy. The absolute venous blood volume change contributes up to 36% of the total blood volume change during hypercapnia. Our findings provide a quantitative physiological model of BOLD contrast. PMID:11323805

  2. Induced hypertension for the treatment of cerebral ischemia after subarachnoid hemorrhage. Direct effect on cerebral blood flow

    SciTech Connect

    Muizelaar, J.P.; Becker, D.P.

    1986-04-01

    The best treatment for symptomatic cerebral ischemia from presumed vasospasm after aneurysmal subarachnoid hemorrhage remains a matter of controversy. A direct effect of any treatment modality on regional cerebral blood flow has never been documented. In a series of 43 patients operated on for ruptured anterior circulation aneurysms, five patients (11.6%) developed clinical signs of cerebral ischemia postoperatively. In four of those patients, the diagnosis of vasospasm was made with measurements of cerebral blood flow (133Xe inhalation or intravenous injection, 10-16 detectors, cerebral blood flow infinity). Treatment with induced arterial hypertension with phenylephrine was instituted. Hemodilution was instituted in one patient; the other three patients already had hematocrits in the range of 33. Within 1 hour, the cerebral blood flow measurement was repeated to document the effect of treatment. The average pretreatment hemispherical blood flow on the operated side was 18.8 mL/100 g per minute, on the contralateral side 21.0 mL/100 g per minute. With treatment these flows increased to 30.8 and 35.8 mL/100 g per minute, respectively. There was also an immediate and obvious positive clinical effect in all patients. The role of measurement of cerebral blood flow in the clinical management of vasospasm is discussed. We stress the theoretical and practical advances of measurements of cerebral blood flow over cerebral angiography, especially in comatose patients.

  3. Evaluation of regional cerebral blood flow in a patient with musical hallucinations.

    PubMed

    Shoyama, Masaru; Ukai, Satoshi; Kitabata, Yuji; Yamamoto, Masahiro; Okumura, Masatoshi; Kose, Asami; Tsuji, Tomikimi; Shinosaki, Kazuhiro

    2010-02-01

    A 52-year-old woman with musical hallucinations was examined using brain single photon emission computed tomography (SPECT) with 99mTc-ECD. Changes in regional cerebral blood flow (rCBF) after carbamazepine treatment were assessed using a three-dimensional stereotaxic ROI template. Following treatment, rCBF was decreased in the subcortical structures and increased in the global cortical regions. From our findings, we propose that rCBF values in subcortical structures represent abnormalities similar to those reported in previous reports or other psychiatric disorders, while those in cortical regions suggest background brain dysfunctions that result in generation of musical hallucinations. PMID:20391182

  4. Cerebral blood flow asymmetries in headache-free migraineurs

    SciTech Connect

    Levine, S.R.; Welch, K.M.; Ewing, J.R.; Joseph, R.; D'Andrea, G.

    1987-11-01

    Regional cerebral blood flow (rCBF) asymmetries were studied in controls and patients with common and classic/complicated migraine using /sup 133/Xe inhalation with 8 homologously situated external collimators over each cerebral hemisphere. Migraine patients as a group more frequently had posterior rCBF asymmetries than controls (p less than 0.03). Although there were no differences in the number of anterior rCBF asymmetries, migraine patients had 2 or more asymmetric probe pairs more often than controls (p less than 0.02). The posterior rCBF asymmetries, consistent with the site of activation of many migraine attacks, may be related to more labile control of the cerebral circulation.

  5. Anxiety, pCO2 and cerebral blood flow.

    PubMed

    Van den Bergh, Omer; Zaman, Jonas; Bresseleers, Johan; Verhamme, Peter; Van Diest, Ilse

    2013-07-01

    This study examined the effect of anxiety on cerebral blood flow at different levels of pCO2 in healthy participants (N=29). Three types of breathing were used to manipulate pCO2 in a within-subject threat-of-shock paradigm: spontaneous breathing, CO2-inhalation and hyperventilation resulting in normo-, hyper- and hypocapnia. Transcranial Doppler ultrasonography was used to measure CBF velocity (CBFv) in the right middle cerebral artery, while breathing behavior and end-tidal pCO2 were monitored. During normocapnia, elevated anxiety was clearly associated with increased CBFv. Consistent with the cerebral vasoconstrictive and vasodilating effects of, respectively, hypo- and hypercapnia, we observed a positive linear association between CBFv and pCO2. The slope of this association became steeper with increasing anxiety, indicating that anxiety enhances the sensitivity of CBFv to changes in pCO2. The findings may elucidate conflicting findings in the literature and are relevant for brain imaging relying on regional cerebral blood flow. PMID:23727628

  6. Cerebral blood flow autoregulation during intracranial hypertension in hypoxic lambs

    SciTech Connect

    Borel, C.O.; Backofen, J.E.; Koehler, R.C.; Jones, M.D. Jr.; Traystman, R.J. )

    1987-12-01

    The authors tested the hypothesis that hypoxic hypoxia interferes with cerebral blood flow (CBF) autoregulation when intracranial pressure (ICP) is elevated in pentobarbital-anesthetized lambs (3 to 9 days old). Cerebral perfusion pressure (CPP) was lowered stepwise from 73 to 23 mmHg in eight normoxic lambs and from 65 to 31 mmHg in eight other hypoxic lambs by ventricular infusion of artificial cerebrospinal fluid. In normoxic lambs, CBF measured by microspheres labeled with six different radioisotopes was not significantly changed over this range of CPP. In animals made hypoxic, base-line CBF was twice that of normoxic lambs. CBF was unchanged as CPP was reduced to 31 mmHg. Lower levels of CPP were not attained because a pressor response occurred with further elevations of ICP. No regional decrements in blood flow to cortical arterial watershed areas or to more caudal regions, such as cerebellum, brain stem, or thalamus, were detected with elevated ICP. Cerebral O{sub 2} uptake was similar in both groups and did not decrease when CPP was reduced. These results demonstrate that normoxic lambs have a considerable capacity for effective autoregulation of CBF when ICP is elevated. Moreover, cerebral vasodilation in response to a level of hypoxia approximating that normally seen prenatally does not abolish CBF autoregulation when ICP is elevated during the first postnatal week.

  7. Cerebral angiography, blood flow and vascular reactivity in progressive hypertension

    PubMed Central

    Li, Yunxia; Shen, Qiang; Huang, Shiliang; Li, Wei; Muir, Eric R.; Long, Justin; Duong, Timothy Q.

    2015-01-01

    Chronic hypertension alters cerebral vascular morphology, cerebral blood flow (CBF), cerebrovascular reactivity, increasing susceptibility to neurological disorders. This study evaluated: i) the lumen diameters of major cerebral and downstream arteries using magnetic resonance angiography, and ii) basal CBF, and iii) cerebrovascular reactivity to hypercapnia of multiple brain regions using arterial-spin-labeling technique in spontaneously hypertensive rats (SHR) at different stages. Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR, lumen diameter started to reduce, basal CBF, and hypercapnic CBF response were higher from elevated arterial blood pressure, but there was no evidence of stenosis, compared to age-matched WKY. In 20-week SHR, lumen diameter remained reduced, CBF returned toward normal from vasoconstriction, hypercapnic CBF response reversed and became smaller, but without apparent stenosis. In 40-week SHR, lumen diameter remained reduced and basal CBF further decreased, resulting in larger differences compared to WKY. There was significant stenosis in main supplying cerebral vessels. Hypercapnic CBF response further decreased, with some animals showing negative hypercapnic CBF responses in some brain regions, indicative of compromised cerebrovascular reserve. The territory with negative hypercapnia CBF responses corresponded with the severity of stenosis in arteries that supplied those territories. We also found enlargement of downstream vessels and formation of collateral vessels as compensatory responses to vasoconstriction upstream vessels. The middle cerebral and azygos arteries were amongst the most susceptible to hypertension-induced changes. Multimodal MRI provides clinically relevant data that might be useful to characterize disease pathogenesis, stage disease progression, and monitor treatment effects in hypertension. PMID:25731987

  8. Regulation of cerebral blood flow after spinal cord injury.

    PubMed

    Phillips, Aaron A; Ainslie, Philip N; Krassioukov, Andrei V; Warburton, Darren E R

    2013-09-15

    Significant cardiovascular and autonomic dysfunction occurs after era spinal cord injury (SCI). Two major conditions arising from autonomic dysfunction are orthostatic hypotension and autonomic dysreflexia (i.e., severe acute hypertension). Effective regulation of cerebral blood flow (CBF) is essential to offset these drastic changes in cerebral perfusion pressure. In the context of orthostatic hypotension and autonomic dysreflexia, the purpose of this review is to critically examine the mechanisms underlying effective CBF after an SCI and propose future avenues for research. Although only 16 studies have examined CBF control in those with high-level SCI (above the sixth thoracic spinal segment), it appears that CBF regulation is markedly altered in this population. Cerebrovascular function comprises three major mechanisms: (1) cerebral autoregulation, (i.e., ΔCBF/Δ blood pressure); (2) cerebrovascular reactivity to changes in PaCO2 (i.e. ΔCBF/arterial gas concentration); and (3) neurovascular coupling (i.e., ΔCBF/Δ metabolic demand). While static cerebral autoregulation appears to be well maintained in high-level SCI, dynamic cerebral autoregulation, cerebrovascular reactivity, and neurovascular coupling appear to be markedly altered. Several adverse complications after high-level SCI may mediate the changes in CBF regulation including: systemic endothelial dysfunction, sleep apnea, dyslipidemia, decentralization of sympathetic control, and dominant parasympathetic activity. Future studies are needed to describe whether altered CBF responses after SCI aid or impede orthostatic tolerance. Further, simultaneous evaluation of extracranial and intracranial CBF, combined with modern structural and functional imaging, would allow for a more comprehensive evaluation of CBF regulatory processes. We are only beginning to understand the functional effects of dysfunctional CBF regulation on brain function on persons with SCI, which are likely to include increased risk

  9. Aging, regional cerebral blood flow, and neuropsychological functioning

    SciTech Connect

    MacInnes, W.D.; Golden, C.J.; Gillen, R.W.; Sawicki, R.F.; Quaife, M.; Uhl, H.S.; Greenhouse, A.J.

    1984-10-01

    Previous studies found changes in regional cerebral blood flow (rCBF) patterns related to both age and various cognitive tasks. However, no study has yet demonstrated a relationship between rCBF and performance on the Luria-Nebraska Neuropsychological Battery (LNNB) in an elderly group. Seventy-nine elderly volunteers (56-88 years old), both healthy and demented, underwent the /sup 133/xenon inhalation rCBF procedure and were given the LNNB. The decrements in the gray-matter blood flow paralleled decrements in performance on the LNNB. Using partial correlations, a significant proportion of shared variance was observed between gray-matter blood flow and the LNNB scales. However, there was much less of a relationship between white-matter blood flow and performance on the LNNB. This study suggests that even within a restricted age sample rCBF is related in a global way to neuropsychological functioning.

  10. Persistence of cerebral metabolic abnormalities in chronic schizophrenia as determined by positron emission tomography

    SciTech Connect

    Wolkin, A.; Jaeger, J.; Brodie, J.D.; Wolf, A.P.; Fowler, J.; Rotrosen, J.; Gomez-Mont, F.; Cancro, R.

    1985-05-01

    Local cerebral metabolic rates were determined by positron emission tomography and the deoxyglucose method in a group of 10 chronic schizophrenic subjects before and after somatic treatment and in eight normal subjects. Before treatment, schizophrenic subjects had markedly lower absolute metabolic activity than did normal controls in both frontal and temporal regions and a trend toward relative hyperactivity in the basal ganglia area. After treatment, their metabolic rates approached those seen in normal subjects in nearly all regions except frontal. Persistence of diminished frontal metabolism was manifested as significant relative hypofrontality. These findings suggest specific loci of aberrant cerebral functioning in chronic schizophrenia and the utility of positron emission tomography in characterizing these abnormalities.

  11. Progressive bone and joint abnormalities of the spine and lower extremities in cerebral palsy.

    PubMed

    Morrell, David S; Pearson, J Michael; Sauser, Donald D

    2002-01-01

    Bone and joint changes in cerebral palsy result from muscle spasticity and contracture. The spine and the joints of the lower extremity are most commonly affected. Scoliosis may progress rapidly and may continue after skeletal maturity. Increased thoracic kyphosis and lumbar lordosis, spondylolisthesis, spondylolysis, and pelvic obliquity may accompany the scoliosis. Progressive hip flexion and adduction lead to windswept deformity, increased femoral anteversion, apparent coxa valga, subluxation, deformity of the femoral head, hip dislocation, and formation of a pseudoacetabulum. In the knee, flexion contracture, patella alta, and patellar fragmentation are the most commonly seen abnormalities. Recurvatum deformity can also develop in the knee secondary to contracture of the rectus femoris muscle. Progressive equinovalgus and equinovarus of the foot and ankle are associated with rocker-bottom deformity and subluxation of the talonavicular joint. Early recognition of progressive deformity in patients with cerebral palsy allows timely treatment and prevention of irreversible change. PMID:11896216

  12. On line cerebral blood flow velocity and blood pressure measurement in neonates: a new method.

    PubMed Central

    Fenton, A C; Evans, D H; Levene, M I

    1990-01-01

    To test the hypothesis that impairment of cerebral perfusion and cerebrovascular autoregulation play a part in the pathogenesis of neurological injury in the critically sick neonate, we tested in 33 infants a small, light-weight probe and cable that are attached to the infant's skin to record cerebral blood flow velocity from the middle cerebral artery over a period of hours. This considerably reduced the amount of handling of the infant compared with conventional assessment. Captured data were analysed and displayed graphically at the cotside. The system is applicable for use on infants over a wide range of gestational ages and may give information on the complex haemodynamic changes occurring in the cerebral circulation. PMID:2407196

  13. Embryologic Association of Tornwaldt's Cyst with Cerebral Artery Abnormalities and Infarction: A Case Report

    PubMed Central

    Osborn, Michael F.; Buchanan, Benjamin K.; Akle, Nassim; Badr, Ahmed; Zhang, Jun

    2012-01-01

    Background and Purpose. Tornwaldt's cysts are rare nasopharyngeal lesions that develop from remnants of the embryonic notochord. Summary of Case. We reported a twelve-year-old female stroke patient with Tornwaldt's cysts, whose father also suffered a stroke at age fifty two with the presence of an abdominal aortic aneurysm, suggesting a genetic influence in this case. Conclusions. This paper suggests an etiologic connection between Tornwaldt's cysts and cerebral vasculature abnormalities by way of notochordal dysfunction during development, likely the result of perturbation of notochord-derived molecular cues during development or biogenesis. PMID:23094173

  14. CEREBRAL BLOOD FLOW AND METABOLISM IN ANXIETY AND ANXIETY DISORDERS

    PubMed Central

    Mathew, Roy J.

    1994-01-01

    Anxiety disorders are some of the commonest psychiatric disorders and anxiety commonly co-exists with other psychiatric conditions. Anxiety can also be a normal emotion. Thus, study of the neurobiological effects of anxiety is of considerable significance. In the normal brain, cerebral blood flow (CBF) and metabolism (CMR) serve as indices of brain function. CBF/CMR research is expected to provide new insight into alterations in brain function in anxiety disorders and other psychiatric disorders. Possible associations between stress I anxiety I panic and cerebral ischemia I stroke give additional significance to the effects of anxiety on CBF. With the advent of non-invasive techniques, study of CBF/CMR in anxiety disorders became easier. A large numbers of research reports are available on the effects of stress, anxiety and panic on CBF/CMR in normals and anxiety disorder patients. This article reviews the available human research on this topic. PMID:21743685

  15. Effect of anxiety on cortical cerebral blood flow and metabolism

    SciTech Connect

    Gur, R.C.; Gur, R.E.; Resnick, S.M.; Skolnick, B.E.; Alavi, A.; Reivich, M.

    1987-04-01

    The relation between anxiety and cortical activity was compared in two samples of normal volunteers. One group was studied with the noninvasive xenon-133 inhalation technique for measuring cerebral blood flow (CBF) and the other with positron emission tomography (PET) using /sup 18/Flurodeoxyglucose (/sup 18/FDG) for measuring cerebral metabolic rates (CMR) for glucose. The inhalation technique produced less anxiety than the PET procedure, and for low anxiety subjects, there was a linear increase in CBF with anxiety. For higher anxiety subjects, however, there was a linear decrease in CBF with increased anxiety. The PET group manifested a linear decrease in CMR with increased anxiety. The results indicate that anxiety can have systematic effects on cortical activity, and this should be taken into consideration when comparing data from different procedures. They also suggest a physiologic explanation of a fundamental behavioral law that stipulates a curvilinear, inverted-U relationship between anxiety and performance.

  16. The Utility of Cerebral Blood Flow Assessment in TBI.

    PubMed

    Akbik, Omar S; Carlson, Andrew P; Krasberg, Mark; Yonas, Howard

    2016-08-01

    Over the past few decades, intracranial monitoring technologies focused on treating and preempting secondary injury after traumatic brain injury (TBI) have experienced considerable growth. A physiological measure fundamental to the management of these patients is cerebral blood flow (CBF), which may be determined directly or indirectly. Direct measurement has proven difficult previously; however, invasive and non-invasive CBF monitors are now available. This article reviews the history of CBF measurements in TBI as well as the role of CBF in pathologies associated with TBI, such as cerebral autoregulation, hyperemia, and cortical spreading depression. The limitations of various CBF monitors are reviewed in order to better understand their role in TBI management. PMID:27315250

  17. Quantitative cerebral blood flow with Optical Coherence Tomography

    PubMed Central

    Srinivasan, Vivek J.; Sakadžić, Sava; Gorczynska, Iwona; Ruvinskaya, Svetlana; Wu, Weicheng; Fujimoto, James G.; Boas, David A.

    2010-01-01

    Absolute measurements of cerebral blood flow (CBF) are an important endpoint in studies of cerebral pathophysiology. Currently no accepted method exists for in vivo longitudinal monitoring of CBF with high resolution in rats and mice. Using three-dimensional Doppler Optical Coherence Tomography and cranial window preparations, we present methods and algorithms for regional CBF measurements in the rat cortex. Towards this end, we develop and validate a quantitative statistical model to describe the effect of static tissue on velocity sensitivity. This model is used to design scanning protocols and algorithms for sensitive 3D flow measurements and angiography of the cortex. We also introduce a method of absolute flow calculation that does not require explicit knowledge of vessel angles. We show that OCT estimates of absolute CBF values in rats agree with prior measures by autoradiography, suggesting that Doppler OCT can perform absolute flow measurements in animal models. PMID:20174075

  18. Synchronization patterns in cerebral blood flow and peripheral blood pressure under minor stroke

    NASA Astrophysics Data System (ADS)

    Chen, Zhi; Ivanov, Plamen C.; Hu, Kun; Stanley, H. Eugene; Novak, Vera

    2003-05-01

    Stroke is a leading cause of death and disability in the United States. The autoregulation of cerebral blood flow that adapts to changes in systemic blood pressure is impaired after stroke. We investigate blood flow velocities (BFV) from right and left middle cerebral arteries (MCA) and beat-to-beat blood pressure (BP) simultaneously measured from the finger, in 13 stroke and 11 healthy subjects using the mean value statistics and phase synchronization method. We find an increase in the vascular resistance and a much stronger cross-correlation with a time lag up to 20 seconds with the instantaneous phase increment of the BFV and BP signals for the subjects with stroke compared to healthy subjects.

  19. Capillary pericytes regulate cerebral blood flow in health and disease

    PubMed Central

    Sutherland, Brad A.; O’Farrell, Fergus M.; Buchan, Alastair M.; Lauritzen, Martin; Attwell, David

    2014-01-01

    Brain blood flow increases, evoked by neuronal activity, power neural computation and are the basis of BOLD functional imaging. It is controversial whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes. We demonstrate that neuronal activity and the neurotransmitter glutamate evoke the release of messengers that dilate capillaries by actively relaxing pericytes. Dilation is mediated by prostaglandin E2, but requires nitric oxide release to suppress vasoconstricting 20-HETE synthesis. In vivo, when sensory input increases blood flow, capillaries dilate before arterioles and are estimated to produce 84% of the blood flow increase. In pathology, ischaemia evokes capillary constriction by pericytes. We show that this is followed by pericyte death in rigor, which may irreversibly constrict capillaries and damage the blood-brain barrier. Thus, pericytes are major regulators of cerebral blood flow and initiators of functional imaging signals. Prevention of pericyte constriction and death may reduce the long-lasting blood flow decrease which damages neurons after stroke. PMID:24670647

  20. Relations of blood pressure and head injury to regional cerebral blood flow.

    PubMed

    Kisser, Jason E; Allen, Allyssa J; Katzel, Leslie I; Wendell, Carrington R; Siegel, Eliot L; Lefkowitz, David; Waldstein, Shari R

    2016-06-15

    Hypertension confers increased risk for cognitive decline, dementia, and cerebrovascular disease. These associations have been attributed, in part, to cerebral hypoperfusion. Here we posit that relations of higher blood pressure to lower levels of cerebral perfusion may be potentiated by a prior head injury. Participants were 87 community-dwelling older adults - 69% men, 90% white, mean age=66.9years, 27.6% with a history of mild traumatic brain injury (mTBI) defined as a loss of consciousness ≤30min resulting from an injury to the head, and free of major medical (other than hypertension), neurological or psychiatric comorbidities. All engaged in clinical assessment of systolic and diastolic blood pressure (SBP, DBP) and single photon emission computed tomography (SPECT). Computerized coding of the SPECT images yielded relative ratios of blood flow in left and right cortical and select subcortical regions. Cerebellum served as the denominator. Sex-stratified multiple regression analyses, adjusted for age, education, race, alcohol consumption, smoking status, and depressive symptomatology, revealed significant interactions of blood pressure and head injury to cerebral blood flow in men only. Specifically, among men with a history of head injury, higher systolic blood pressure was associated with lower levels of perfusion in the left orbital (β=-3.21, p=0.024) and left dorsolateral (β=-2.61, p=0.042) prefrontal cortex, and left temporal cortex (β=-3.36, p=0.014); higher diastolic blood pressure was marginally associated with lower levels of perfusion in the left dorsolateral prefrontal cortex (β=-2.79, p=0.051). Results indicate that men with a history of head injury may be particularly vulnerable to the impact of higher blood pressure on cerebral perfusion in left anterior cortical regions, thus potentially enhancing risk for adverse brain and neurocognitive outcomes. PMID:27206865

  1. Cerebral blood flow is reduced in patients with sepsis syndrome

    SciTech Connect

    Bowton, D.L.; Bertels, N.H.; Prough, D.S.; Stump, D.A.

    1989-05-01

    The relationship between sepsis-induced CNS dysfunction and changes in brain blood flow remains unknown, and animal studies examining the influence of sepsis on cerebral blood flow (CBF) do not satisfactorily address that relationship. We measured CBF and cerebrovascular reactivity to CO/sub 2/ in nine patients with sepsis syndrome using the /sup 133/Xe clearance technique. Mean CBF was 29.6 +/- 15.8 (SD) ml/100 g.min, significantly lower than the normal age-matched value in this laboratory of 44.9 +/- 6.2 ml/100 g.min (p less than .02). This depression did not correlate with changes in mean arterial pressure. Despite the reduction in CBF, the specific reactivity of the cerebral vasculature to changes in CO/sub 2/ was normal, 1.3 +/- 0.9 ml/100 g.min/mm Hg. Brain blood flow is reduced in septic humans; the contribution of this reduction to the metabolic and functional changes observed in sepsis requires further study.

  2. Ion channel networks in the control of cerebral blood flow.

    PubMed

    Longden, Thomas A; Hill-Eubanks, David C; Nelson, Mark T

    2016-03-01

    One hundred and twenty five years ago, Roy and Sherrington made the seminal observation that neuronal stimulation evokes an increase in cerebral blood flow.(1) Since this discovery, researchers have attempted to uncover how the cells of the neurovascular unit-neurons, astrocytes, vascular smooth muscle cells, vascular endothelial cells and pericytes-coordinate their activity to control this phenomenon. Recent work has revealed that ionic fluxes through a diverse array of ion channel species allow the cells of the neurovascular unit to engage in multicellular signaling processes that dictate local hemodynamics.In this review we center our discussion on two major themes: (1) the roles of ion channels in the dynamic modulation of parenchymal arteriole smooth muscle membrane potential, which is central to the control of arteriolar diameter and therefore must be harnessed to permit changes in downstream cerebral blood flow, and (2) the striking similarities in the ion channel complements employed in astrocytic endfeet and endothelial cells, enabling dual control of smooth muscle from either side of the blood-brain barrier. We conclude with a discussion of the emerging roles of pericyte and capillary endothelial cell ion channels in neurovascular coupling, which will provide fertile ground for future breakthroughs in the field. PMID:26661232

  3. Regional cerebral blood flow during comprehension and speech (in cerebrally healthy subjects)

    SciTech Connect

    Lechevalier, B.; Petit, M.C.; Eustache, F.; Lambert, J.; Chapon, F.; Viader, F. )

    1989-07-01

    Regional cerebral blood flow (rCBF) was measured by the xenon-133 inhalation method in 10 cerebrally healthy subjects at rest and during linguistic activation tests. These consisted of a comprehension test (binaural listening to a narrative text) and a speech test (making sentences from a list of words presented orally at 30-s intervals). The comprehension task induced a moderate increase in the mean right CBF and in both inferior parietal areas, whereas the speech test resulted in a diffuse increase in the mean CBF of both hemispheres, predominating regionally in both inferior parietal, left operculary, and right upper motor and premotor areas. It is proposed that the activation pattern induced by linguistic stimulation depends on not only specific factors, such as syntactic and semantic aspects of language, but also the contents of the material proposed and the attention required by the test situation.

  4. In Utero Bisphenol A Exposure Induces Abnormal Neuronal Migration in the Cerebral Cortex of Mice

    PubMed Central

    Ling, Wenting; Endo, Toshihiro; Kubo, Ken-ichiro; Nakajima, Kazunori; Kakeyama, Masaki; Tohyama, Chiharu

    2016-01-01

    Bisphenol A (BPA) has been known to have endocrine-disrupting activity to induce reproductive and behavioral abnormalities in offspring of laboratory animal species. However, morphological basis of this abnormality during brain development is largely unknown. Cerebral cortex plays a crucial role in higher brain function, and its precisely laminated structure is formed by neuronal migration. In the present study, transfecting a plasmid (pCAG-mCherry) by in utero electroporation (IUE), we visualized developing neurons and investigated the possible effects of in utero BPA exposure on neuronal migration. Pregnant mice were exposed to BPA by osmotic pump at estimated daily doses of 0, 40 (BPA-40), or 400 (BPA-400) μg/kg from embryonic day 14.5 (E14.5) to E18.5. IUE was performed at E14.5 and neuronal migration was analyzed at E18.5. Compared with the control group, neuronal migration in the cortical plate was significantly decreased in the BPA-40 group; however, there was no significant difference in the BPA-400 group. Among several neuronal migration-related genes and cortical layer-specific genes, TrkB in the BPA-400 group was found significantly upregulated. In conclusion, in utero exposure to low BPA dose was found to disrupt neuronal migration in the cerebral cortex in a dose-specific manner. PMID:26869994

  5. Regional cerebral blood flow in essential hypertension: data evaluation by a mapping system

    SciTech Connect

    Rodriguez, G.; Arvigo, F.; Marenco, S.; Nobili, F.; Romano, P.; Sandini, G.; Rosadini, G.

    1987-01-01

    Regional cerebral blood flow was studied by means of the 133Xe inhalation method in 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal regions in the previously diagnosed group, and this was attributed to pathological changes in the district served by the middle cerebral artery. Regional temporal lobe impairment was also noted in the newly diagnosed and treated subjects. A significant correlation was found between regional cerebral blood flow and mean arterial blood pressure.

  6. Abnormal Excitability and Episodic Low-Frequency Oscillations in the Cerebral Cortex of the tottering Mouse

    PubMed Central

    Cramer, Samuel W.; Popa, Laurentiu S.; Carter, Russell E.; Chen, Gang

    2015-01-01

    The Ca2+ channelopathies caused by mutations of the CACNA1A gene that encodes the pore-forming subunit of the human Cav2.1 (P/Q-type) voltage-gated Ca2+ channel include episodic ataxia type 2 (EA2). Although, in EA2 the emphasis has been on cerebellar dysfunction, patients also exhibit episodic, nonmotoric abnormalities involving the cerebral cortex. This study demonstrates episodic, low-frequency oscillations (LFOs) throughout the cerebral cortex of tottering (tg/tg) mice, a widely used model of EA2. Ranging between 0.035 and 0.11 Hz, the LFOs in tg/tg mice can spontaneously develop very high power, referred to as a high-power state. The LFOs in tg/tg mice are mediated in part by neuronal activity as tetrodotoxin decreases the oscillations and cortical neuron discharge contain the same low frequencies. The high-power state involves compensatory mechanisms because acutely decreasing P/Q-type Ca2+ channel function in either wild-type (WT) or tg/tg mice does not induce the high-power state. In contrast, blocking l-type Ca2+ channels, known to be upregulated in tg/tg mice, reduces the high-power state. Intriguingly, basal excitatory glutamatergic neurotransmission constrains the high-power state because blocking ionotropic or metabotropic glutamate receptors results in high-power LFOs in tg/tg but not WT mice. The high-power LFOs are decreased markedly by acetazolamide and 4-aminopyridine, the primary treatments for EA2, suggesting disease relevance. Together, these results demonstrate that the high-power LFOs in the tg/tg cerebral cortex represent a highly abnormal excitability state that may underlie noncerebellar symptoms that characterize CACNA1A mutations. PMID:25855180

  7. Abnormal excitability and episodic low-frequency oscillations in the cerebral cortex of the tottering mouse.

    PubMed

    Cramer, Samuel W; Popa, Laurentiu S; Carter, Russell E; Chen, Gang; Ebner, Timothy J

    2015-04-01

    The Ca(2+) channelopathies caused by mutations of the CACNA1A gene that encodes the pore-forming subunit of the human Cav2.1 (P/Q-type) voltage-gated Ca(2+) channel include episodic ataxia type 2 (EA2). Although, in EA2 the emphasis has been on cerebellar dysfunction, patients also exhibit episodic, nonmotoric abnormalities involving the cerebral cortex. This study demonstrates episodic, low-frequency oscillations (LFOs) throughout the cerebral cortex of tottering (tg/tg) mice, a widely used model of EA2. Ranging between 0.035 and 0.11 Hz, the LFOs in tg/tg mice can spontaneously develop very high power, referred to as a high-power state. The LFOs in tg/tg mice are mediated in part by neuronal activity as tetrodotoxin decreases the oscillations and cortical neuron discharge contain the same low frequencies. The high-power state involves compensatory mechanisms because acutely decreasing P/Q-type Ca(2+) channel function in either wild-type (WT) or tg/tg mice does not induce the high-power state. In contrast, blocking l-type Ca(2+) channels, known to be upregulated in tg/tg mice, reduces the high-power state. Intriguingly, basal excitatory glutamatergic neurotransmission constrains the high-power state because blocking ionotropic or metabotropic glutamate receptors results in high-power LFOs in tg/tg but not WT mice. The high-power LFOs are decreased markedly by acetazolamide and 4-aminopyridine, the primary treatments for EA2, suggesting disease relevance. Together, these results demonstrate that the high-power LFOs in the tg/tg cerebral cortex represent a highly abnormal excitability state that may underlie noncerebellar symptoms that characterize CACNA1A mutations. PMID:25855180

  8. The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia.

    PubMed

    Kay, Victoria L; Rickards, Caroline A

    2016-02-15

    Tolerance to central hypovolemia is highly variable, and accumulating evidence suggests that protection of anterior cerebral blood flow (CBF) is not an underlying mechanism. We hypothesized that individuals with high tolerance to central hypovolemia would exhibit protection of cerebral oxygenation (ScO2), and prolonged preservation of CBF in the posterior vs. anterior cerebral circulation. Eighteen subjects (7 male/11 female) completed a presyncope-limited lower body negative pressure (LBNP) protocol (3 mmHg/min onset rate). ScO2 (via near-infrared spectroscopy), middle cerebral artery velocity (MCAv), posterior cerebral artery velocity (PCAv) (both via transcranial Doppler ultrasound), and arterial pressure (via finger photoplethysmography) were measured continuously. Subjects who completed ≥70 mmHg LBNP were classified as high tolerant (HT; n = 7) and low tolerant (LT; n = 11) if they completed ≤60 mmHg LBNP. The minimum difference in LBNP tolerance between groups was 193 s (LT = 1,243 ± 185 s vs. HT = 1,996 ± 212 s; P < 0.001; Cohen's d = 3.8). Despite similar reductions in mean MCAv in both groups, ScO2 decreased in LT subjects from -15 mmHg LBNP (P = 0.002; Cohen's d=1.8), but was maintained at baseline values until -75 mmHg LBNP in HT subjects (P < 0.001; Cohen's d = 2.2); ScO2 was lower at -30 and -45 mmHg LBNP in LT subjects (P ≤ 0.02; Cohen's d ≥ 1.1). Similarly, mean PCAv decreased below baseline from -30 mmHg LBNP in LT subjects (P = 0.004; Cohen's d = 1.0), but remained unchanged from baseline in HT subjects until -75 mmHg (P = 0.006; Cohen's d = 2.0); PCAv was lower at -30 and -45 mmHg LBNP in LT subjects (P ≤ 0.01; Cohen's d ≥ 0.94). Individuals with higher tolerance to central hypovolemia exhibit prolonged preservation of CBF in the posterior cerebral circulation and sustained cerebral tissue oxygenation, both associated with a delay in the onset of presyncope. PMID:26676249

  9. In vivo cerebral blood flow autoregulation studies using rheoencephalography

    NASA Astrophysics Data System (ADS)

    Bodo, M.; Pearce, F.; Garcia, A.; Van Albert, S.; Settle, T.; Szebeni, J.; Baranyi, L.; Hartings, J.; Armonda, R.

    2010-04-01

    Acute management of patients with traumatic brain/blast injury is a challenge. To minimize secondary injury and improve outcome, it is critical to detect neurological deterioration early, when it is potentially reversible. One potential monitoring method is cerebral electrical impedance (rheoencephalography-REG) because of its non-invasiveness and good time resolution. Reported here are the results of cerebral blood flow (CBF) manipulations comparing electroencephalogram (EEG) with REG (both intra-cerebral) and measuring with surface and skull REG electrodes. Our hypothesis was that REG would reflect spreading depression and CBF autoregulation. Animal experiments were performed using one rat (four trials with intracerebral electrodes), monkeys (n=8, with surface electrodes) and pigs (n = 24 pigs with skull electrodes; 57 trials, 19 types of liposomes). Challenges included intracranial pressure (ICP) elevation, liposome infusion, and hemorrhage. Data were stored on a PC and evaluated off line. CBF autoregulation was evaluated both by visual inspection and by a Matlab script. These studies confirmed that REG reflects CBF autoregulation and that REG is useful for detecting spreading depression (SD), vasospasm and the lower limit of CBF autoregulation. These findings have clinical relevance for use in noninvasive neuro-monitoring in the neurosurgery intensive care and during transportation of patients with brain injury.

  10. Brief Report: Alterations in Cerebral Blood Flow as Assessed by PET/CT in Adults with Autism Spectrum Disorder with Normal IQ

    ERIC Educational Resources Information Center

    Pagani, Marco; Manouilenko, Irina; Stone-Elander, Sharon; Odh, Richard; Salmaso, Dario; Hatherly, Robert; Brolin, Fredrik; Jacobsson, Hans; Larsson, Stig A.; Bejerot, Susanne

    2012-01-01

    Specific biological markers for Autism Spectrum Disorder (ASD) have not yet been established. Functional studies have shown abnormalities in the anatomo-functional connectivity of the limbic-striatal "social" brain. This study aimed to investigate regional cerebral blood flow (rCBF) at rest. Thirteen patients with ASD of normal intelligence and…

  11. Impacts of small arteriovenous malformations (AVM) on regional cerebral blood flow and glucose metabolism

    SciTech Connect

    Liu, R.S.; Yeh, S.H.; Chu, L.S.

    1994-05-01

    This study assessed the effects of small AVMs (<3 cm) on the regional cerebral blood flow (rCBF) by Tc-99m HMPAO SPECT and on the glucose metabolism (rCGlcM) by [F-18]-FDG PET. Seven AVM patients (pts) were studied. All AVMs were confirmed by cerebral angiography and CT/MR scans. Tc-99m HMPAO SPECT and [F-18]-PDG PET images were interpreted visually to detect the changes of rCBF and rCGlcM. All pts except one brain stem AVM had defects in the regions of nidi on HMPAO and FDG images. FDG PET disclosed low rCGlcM in surrounding areas of AVMs in 6 pts, while HMPAO SPECT detected only 4 cases. One AVM had increased rCBF surrounding the nidus despite of decreased rCGlcM in the same region. Five pts had abnormal rCGlcM over ipsilateral remote cortex but only one had corresponding abnormal rCBF. Contralateral cortical hypofunction was noted in 3 pts by FDG PET but none by HMPAO SPECT. Cross cerebellar diaschisis was found in 2 AVMs by FDG PET and only one by HMPAO SPECT. All regions with abnormal HMPAO uptake did not look as discernibly as seen on the FDG PET scan. CT/MR scans detected the nidi of AVMs of all pts and old hemorrhage in one pt. In conclusion, either HMPAO SPECT or FDG PET is sensitive to detect the functional abnormalities in the region of nidus of small AVM and the surrounding brain tissue. FDG PET is better than HMPAO SPECT to detect functional changes in the remote cortex and diaschisis.

  12. Significance of Cerebral Blood Flow Analysis in the Acute Stage after Revascularization Surgery for Moyamoya Disease

    PubMed Central

    FUJIMURA, Miki; TOMINAGA, Teiji

    2015-01-01

    Moyamoya disease is a chronic, occlusive cerebrovascular disease with unknown etiology characterized by steno-occlusive changes at the terminal portion of the internal carotid artery, either bilaterally or unilaterally, and an abnormal vascular network at the base of the brain. Surgical revascularization such as extracranial-intracranial (EC-IC) bypass is the preferred procedure for moyamoya disease. Despite the favorable long-term outcome, cerebral infarction and hyperperfusion syndrome are potential complications of this procedure, which can lead to neurological deterioration in the acute stage. In light of the similar clinical presentations between perioperative ischemia and hyperperfusion, it is essential to attempt a prompt cerebral blood flow (CBF) measurement in the acute stage after EC-IC bypass for moyamoya disease to differentiate these distinct pathologies, because the management of cerebral ischemia and hyperperfusion is contradictory to each other. Routine CBF analysis by single-photon emission computed tomography and/or magnetic resonance imaging not only facilitated a safer perioperative management but also provided important information about dynamic pathology of the hemodynamic conversion in the acute stage after revascularization surgery for moyamoya disease. We represent the current status of CBF analysis during the perioperative period of revascularization surgery for moyamoya disease, and sought to discuss its significance and efficacy to avoid surgical complications. PMID:26369873

  13. Radioactive microsphere study of cerebral blood flow under acceleration. Technical report

    SciTech Connect

    Greenlees, K.J.; Yoder, J.E.; Toth, D.M.; Oloff, C.M.; Karl, A.

    1980-11-01

    A study using radioactive microspheres for the investigation of cerebral blood flow during acceleration is described. Details of a technique for the blunt dissection of cerebral tissues are included. Results of flow studies at 3 and 5 G sub z acceleration stress indicate there is no selective regional preservation of cerebral tissue. (Author)

  14. [Blood viscosity and blood factors in non-embolic cerebral infarction].

    PubMed

    Fong, C S; Chia, L G

    1990-11-01

    We compared blood viscosity at a high and a low shear rate, hematocrit, as well as levels of fibrinogen, cholesterol, triglyceride and high density lipoprotein-cholesterol between 42 patients with nonembolic cerebral infarction and 39 normal subjects. Blood viscosity, levels of fibrinogen, cholesterol and triglyceride were significantly higher, and high density lipoprotein-cholesterol levels were significantly lower, in patients than in normal persons. Blood viscosity had a positive correlation with hematocrit and fibrinogen, and a negative correlation with high density lipoprotein-cholesterol, but no correlation with cholesterol and triglyceride. PMID:1982124

  15. Pentobarbital changes compartmental contribution to cerebral blood flow

    SciTech Connect

    Laurent, J.P.; Lawner, P.; Simeone, F.A.; Fink, E.

    1982-04-01

    Barbiturates were administered to normal dogs, establishing an isoelectric electrocorticogram. Cortical cerebral blood flows (CBF) and deeper CBF's were respectively measured by krypton-85 (85Kr) and xenon-133 (133 Xe). Following barbiturate administration, the two methods of measuring CBF showed a poor coefficient of variation (r.0.12, p less than 0.05). The cortical flows decreased less than the fast compartment flows. A shifting of percentage contribution of flow to the slow compartment (60% increase, p less than 0.001) was observed after barbiturate infusion. A selective shunting of blood flow to the slower areas may explain the lowering of intracranial pressure and protection of the deep white matter observed by many authors who use barbiturates in clinical an experimental situations.

  16. Frontiers in optical imaging of cerebral blood flow and metabolism

    PubMed Central

    Devor, Anna; Sakadžić, Sava; Srinivasan, Vivek J; Yaseen, Mohammad A; Nizar, Krystal; Saisan, Payam A; Tian, Peifang; Dale, Anders M; Vinogradov, Sergei A; Franceschini, Maria Angela; Boas, David A

    2012-01-01

    In vivo optical imaging of cerebral blood flow (CBF) and metabolism did not exist 50 years ago. While point optical fluorescence and absorption measurements of cellular metabolism and hemoglobin concentrations had already been introduced by then, point blood flow measurements appeared only 40 years ago. The advent of digital cameras has significantly advanced two-dimensional optical imaging of neuronal, metabolic, vascular, and hemodynamic signals. More recently, advanced laser sources have enabled a variety of novel three-dimensional high-spatial-resolution imaging approaches. Combined, as we discuss here, these methods are permitting a multifaceted investigation of the local regulation of CBF and metabolism with unprecedented spatial and temporal resolution. Through multimodal combination of these optical techniques with genetic methods of encoding optical reporter and actuator proteins, the future is bright for solving the mysteries of neurometabolic and neurovascular coupling and translating them to clinical utility. PMID:22252238

  17. Determinants of resting cerebral blood flow in sickle cell disease.

    PubMed

    Bush, Adam M; Borzage, Matthew T; Choi, Soyoung; Václavů, Lena; Tamrazi, Benita; Nederveen, Aart J; Coates, Thomas D; Wood, John C

    2016-09-01

    Stroke is common in children with sickle cell disease and results from an imbalance in oxygen supply and demand. Cerebral blood flow (CBF) is increased in patients with sickle cell disease to compensate for their anemia, but adequacy of their oxygen delivery has not been systematically demonstrated. This study examined the physiological determinants of CBF in 37 patients with sickle cell disease, 38 ethnicity matched control subjects and 16 patients with anemia of non-sickle origin. Cerebral blood flow was measured using phase contrast MRI of the carotid and vertebral arteries. CBF increased inversely to oxygen content (r(2)  = 0.69, P < 0.0001). Brain oxygen delivery, the product of CBF and oxygen content, was normal in all groups. Brain composition, specifically the relative amounts of grey and white matter, was the next strongest CBF predictor, presumably by influencing cerebral metabolic rate. Grey matter/white matter ratio and CBF declined monotonically until the age of 25 in all subjects, consistent with known maturational changes in brain composition. Further CBF reductions were observed with age in subjects older than 35 years of age, likely reflecting microvascular aging. On multivariate regression, CBF was independent of disease state, hemoglobin S, hemoglobin F, reticulocyte count and cell free hemoglobin, suggesting that it is regulated similarly in patients and control subjects. In conclusion, sickle cell disease patients had sufficient oxygen delivery at rest, but accomplish this only by marked increases in their resting CBF, potentially limiting their ability to further augment flow in response to stress. Am. J. Hematol. 91:912-917, 2016. © 2016 Wiley Periodicals, Inc. PMID:27263497

  18. Autoregulation of cerebral blood flow in orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Novak, V.; Novak, P.; Spies, J. M.; Low, P. A.

    1998-01-01

    BACKGROUND AND PURPOSE: We sought to evaluate cerebral autoregulation in patients with orthostatic hypotension (OH). METHODS: We studied 21 patients (aged 52 to 78 years) with neurogenic OH during 80 degrees head-up tilt. Blood flow velocities (BFV) from the middle cerebral artery were continuously monitored with transcranial Doppler sonography, as were heart rate, blood pressure (BP), cardiac output, stroke volume, CO2, total peripheral resistance, and cerebrovascular resistance. RESULTS: All OH patients had lower BP (P<.0001), BFV_diastolic (P<.05), CVR (P<.007), and TPR (P<.02) during head-up tilt than control subjects. In control subjects, no correlations between BFV and BP were found during head-up tilt, suggesting normal autoregulation. OH patients could be separated into those with normal or expanded autoregulation (OH_NA; n=16) and those with autoregulatory failure (OH_AF; n=5). The OH_NA group showed either no correlation between BFV and BP (n=8) or had a positive BFV/BP correlation (R2>.75) but with a flat slope. An expansion of the "autoregulated" range was seen in some patients. The OH_AF group was characterized by a profound fall in BFV in response to a small reduction in BP (mean deltaBP <40 mm Hg; R2>.75). CONCLUSIONS: The most common patterns of cerebral response to OH are autoregulatory failure with a flat flow-pressure relationship or intact autoregulation with an expanded autoregulated range. The least common pattern is autoregulatory failure with a steep flow-pressure relationship. Patients with patterns 1 and 2 have an enhanced capacity to cope with OH, while those with pattern 3 have reduced capacity.

  19. Blood biomarkers in the early stage of cerebral ischemia.

    PubMed

    Maestrini, I; Ducroquet, A; Moulin, S; Leys, D; Cordonnier, C; Bordet, R

    2016-03-01

    In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke-within 72h of its onset-as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed. PMID:26988891

  20. Cerebral blood flow in patients with congestive heart failure treated with captopril

    SciTech Connect

    Paulson, O.B.; Jarden, J.O.; Godtfredsen, J.; Vorstrup, S.

    1984-05-31

    The effect of captopril on cerebral blood flow was studied in five patients with severe congestive heart failure and in five control subjects. Cerebral blood flow was measured by inhalation of /sup 133/xenon and registration of its uptake and washout from the brain by single photon emission computer tomography. In addition, cerebral (internal jugular) venous oxygen tension was determined in the controls. The measurements were made before and 15, 60, and 180 minutes after a single oral dose of captopril (6.25 mg in patients with congestive heart failure and 25 mg in controls). Despite a marked decrease in blood pressure, cerebral blood flow increased slightly in the patients with severe congestive heart failure. When a correction was applied to take account of a change in arterial carbon dioxide tension, however, cerebral blood flow was unchanged after captopril administration even in patients with the greatest decrease in blood pressure, in whom a decrease in cerebral blood flow might have been expected. In the controls, blood pressure was little affected by captopril, whereas a slight, but not statistically significant, decrease in cerebral blood flow was observed. The cerebral venous oxygen tension decreased concomitantly.

  1. Influence of probe pressure on the diffuse correlation spectroscopy blood flow signal: extra-cerebral contributions.

    PubMed

    Mesquita, Rickson C; Schenkel, Steven S; Minkoff, David L; Lu, Xiangping; Favilla, Christopher G; Vora, Patrick M; Busch, David R; Chandra, Malavika; Greenberg, Joel H; Detre, John A; Yodh, A G

    2013-07-01

    A pilot study explores relative contributions of extra-cerebral (scalp/skull) versus brain (cerebral) tissues to the blood flow index determined by diffuse correlation spectroscopy (DCS). Microvascular DCS flow measurements were made on the head during baseline and breath-holding/hyperventilation tasks, both with and without pressure. Baseline (resting) data enabled estimation of extra-cerebral flow signals and their pressure dependencies. A simple two-component model was used to derive baseline and activated cerebral blood flow (CBF) signals, and the DCS flow indices were also cross-correlated with concurrent Transcranial Doppler Ultrasound (TCD) blood velocity measurements. The study suggests new pressure-dependent experimental paradigms for elucidation of blood flow contributions from extra-cerebral and cerebral tissues. PMID:23847725

  2. Cerebral Blood Flow Autoregulation Is Preserved After Continuous Flow Left Ventricular Assist Device Implantation

    PubMed Central

    Ono, Masahiro; Joshi, Brijen; Brady, Kenneth; Easley, R. Blaine; Kibler, Kathy; Conte, John; Shah, Ashish; Russell, Stuart D.; Hogue, Charles W.

    2012-01-01

    Objective To compare cerebral blood flow (CBF) autoregulation in patients undergoing continuous flow left ventricular assist device (LVAD) implantation with that in patients undergoing coronary artery bypass graft (CABG) surgery. Design Prospective, observational, controlled study. Setting Academic medical center. Participants Fifteen patients undergoing LVAD insertion and 10 patients undergoing CABG surgery. Measurements and Main Results Cerebral autoregulation was monitored with transcranial Doppler and near-infrared spectroscopy (NIRS). A continuous, Pearson's correlation coefficient was calculated between mean arterial pressure (MAP) and CBF velocity, and between MAP and NIRS data rendering the variables mean velocity index (Mx) and cerebral oximetry index (COx), respectively. Mx and COx approach zero when autoregulation is intact (no correlation between CBF and MAP), but approach 1 when autoregulation is impaired. Mx was lower during and immediately after cardiopulmonary bypass (CPB) in the LVAD group than it was in the CABG surgery patients, indicating better preserved autoregulation. Based on COx monitoring, autoregulation tended to be better preserved in the LVAD group than in the CABG group immediately after surgery (p=0.0906). On postoperative day 1, COx was lower in LVAD patients than in CABG surgery patients, again indicating preserved CBF autoregulation (p=0.0410). Based on COx monitoring, 3 (30%) of the CABG patients had abnormal autoregulation (COx ≥ 0.3) on the first postoperative day but none of the LVAD patients had this abnormality (p=0.037). Conclusion These data suggest that CBF autoregulation is preserved during and immediately after surgery in patients undergoing LVAD insertion. PMID:23122299

  3. Effects of forskolin on cerebral blood flow: implications for a role of adenylate cyclase

    SciTech Connect

    Wysham, D.G.; Brotherton, A.F.; Heistad, D.D.

    1986-11-01

    We have studied cerebral vascular effects of forskolin, a drug which stimulates adenylate cyclase and potentiates dilator effects of adenosine in other vascular beds. Our goals were to determine whether forskolin is a cerebral vasodilator and whether it potentiates cerebral vasodilator responses to adenosine. We measured cerebral blood flow with microspheres in anesthetized rabbits. Forskolin (10 micrograms/kg per min) increased blood flow (ml/min per 100 gm) from 39 +/- 5 (mean +/- S.E.) to 56 +/- 9 (p less than 0.05) in cerebrum, and increased flow to myocardium and kidney despite a decrease in mean arterial pressure. Forskolin did not alter cerebral oxygen consumption, which indicates that the increase in cerebral blood flow is a direct vasodilator effect and is not secondary to increased metabolism. We also examined effects of forskolin on the response to infusion of adenosine. Cerebral blood flow was measured during infusion of 1-5 microM/min adenosine into one internal carotid artery, under control conditions and during infusion of forskolin at 3 micrograms/kg per min i.v. Adenosine alone increased ipsilateral cerebral blood flow from 32 +/- 3 to 45 +/- 5 (p less than 0.05). Responses to adenosine were not augmented during infusion of forskolin. We conclude that forskolin is a direct cerebral vasodilator and forskolin does not potentiate cerebral vasodilator responses to adenosine.

  4. The effect of an acute increase in central blood volume on the response of cerebral blood flow to acute hypotension.

    PubMed

    Ogoh, Shigehiko; Hirasawa, Ai; Sugawara, Jun; Nakahara, Hidehiro; Ueda, Shinya; Shoemaker, J Kevin; Miyamoto, Tadayoshi

    2015-09-01

    The purpose of the present study was to examine whether the response of cerebral blood flow to an acute change in perfusion pressure is modified by an acute increase in central blood volume. Nine young, healthy subjects voluntarily participated in this study. To measure dynamic cerebral autoregulation during normocapnic and hypercapnic (5%) conditions, the change in middle cerebral artery mean blood flow velocity was analyzed during acute hypotension caused by two methods: 1) thigh-cuff occlusion release (without change in central blood volume); and 2) during the recovery phase immediately following release of lower body negative pressure (LBNP; -50 mmHg) that initiated an acute increase in central blood volume. In the thigh-cuff occlusion release protocol, as expected, hypercapnia decreased the rate of regulation, as an index of dynamic cerebral autoregulation (0.236 ± 0.018 and 0.167 ± 0.025 s(-1), P = 0.024). Compared with the cuff-occlusion release, the acute increase in central blood volume (relative to the LBNP condition) with LBNP release attenuated dynamic cerebral autoregulation (P = 0.009). Therefore, the hypercapnia-induced attenuation of dynamic cerebral autoregulation was not observed in the LBNP release protocol (P = 0.574). These findings suggest that an acute change in systemic blood distribution modifies dynamic cerebral autoregulation during acute hypotension. PMID:26159757

  5. Cerebral abnormalities in cocaine abusers: Demonstration by SPECT perfusion brain scintigraphy. Work in progress

    SciTech Connect

    Tumeh, S.S.; Nagel, J.S.; English, R.J.; Moore, M.; Holman, B.L. )

    1990-09-01

    Single photon emission computed tomography (SPECT) perfusion brain scans with iodine-123 isopropyl iodoamphetamine (IMP) were obtained in 12 subjects who acknowledged using cocaine on a sporadic to a daily basis. The route of cocaine administration varied from nasal to intravenous. Concurrent abuse of other drugs was also reported. None of the patients were positive for human immunodeficiency virus. Brain scans demonstrated focal defects in 11 subjects, including seven who were asymptomatic, and no abnormality in one. Among the findings were scattered focal cortical deficits, which were seen in several patients and which ranged in severity from small and few to multiple and large, with a special predilection for the frontal and temporal lobes. No perfusion deficits were seen on I-123 SPECT images in five healthy volunteers. Focal alterations in cerebral perfusion are seen commonly in asymptomatic drug users, and these focal deficits are readily depicted by I-123 IMP SPECT.

  6. Effect of high dose isoflurane on cerebral blood flow in macaque monkeys

    PubMed Central

    Li, Chun-Xia; Patel, Sudeep; Wang, Danny JJ; Zhang, Xiaodong

    2014-01-01

    The effect of high dose isoflurane on cerebral blood flow (CBF) was investigated in adult macaque monkeys receiving 1% to 2% isoflurane with the pseudo continuous arterial-spin-labeling (pCASL) MRI technique. High concentration (2%) of isoflurane resulted in significant increase in the mean CBF of the global, cortical, subcortical regions and the regional CBF in all subcortical structures and most cortical structures (such as motor cortex, anterior cingulate cortex, but not media prefrontal cortex). In addition, the changes of regional CBF in the affected regions correlated linearly with increasing isoflurane concentrations. The study demonstrates region specific CBF abnormal increase in adult macaque monkeys under high dose (2%) isoflurane and suggests the brain functionality in corresponding structures may be affected and need to be taken consideration in either human or non-human primate neuroimaging studies. PMID:24890304

  7. Effect of flunarizine on regional cerebral blood flow in common and complicated migraine. Pilot study.

    PubMed

    Lagrèze, H L; Tsuda, Y; Hartmann, A; Bülau, P

    1986-01-01

    Alterations of regional cerebral blood flow (rCBF) are at least epiphenomena of common and complicated migraine, but may lead to serious clinical complications. Since flunarizine seems to be effective in migraine prevention it may exert a beneficial influence on rCBF in migraine as well. rCBF was assessed using the 133Xe inhalation method in 5 patients with common and 8 patients with complicated migraine. Measurements were done interictally prior and after therapy with 15 mg flunarizine p.o. daily over a period of 4 weeks. Major abnormalities of grey matter flow were observed even interictally. Significant improvement of rCBF in initially hypoemic regions may be attributed to flunarizine therapy. These preliminary data suggest that calcium entry blockers may prevent the ischemic complications of migraine. PMID:3093236

  8. Hypoxemia, oxygen content, and the regulation of cerebral blood flow.

    PubMed

    Hoiland, Ryan L; Bain, Anthony R; Rieger, Mathew G; Bailey, Damian M; Ainslie, Philip N

    2016-03-01

    This review highlights the influence of oxygen (O2) availability on cerebral blood flow (CBF). Evidence for reductions in O2 content (CaO2 ) rather than arterial O2 tension (PaO2 ) as the chief regulator of cerebral vasodilation, with deoxyhemoglobin as the primary O2 sensor and upstream response effector, is discussed. We review in vitro and in vivo data to summarize the molecular mechanisms underpinning CBF responses during changes in CaO2 . We surmise that 1) during hypoxemic hypoxia in healthy humans (e.g., conditions of acute and chronic exposure to normobaric and hypobaric hypoxia), elevations in CBF compensate for reductions in CaO2 and thus maintain cerebral O2 delivery; 2) evidence from studies implementing iso- and hypervolumic hemodilution, anemia, and polycythemia indicate that CaO2 has an independent influence on CBF; however, the increase in CBF does not fully compensate for the lower CaO2 during hemodilution, and delivery is reduced; and 3) the mechanisms underpinning CBF regulation during changes in O2 content are multifactorial, involving deoxyhemoglobin-mediated release of nitric oxide metabolites and ATP, deoxyhemoglobin nitrite reductase activity, and the downstream interplay of several vasoactive factors including adenosine and epoxyeicosatrienoic acids. The emerging picture supports the role of deoxyhemoglobin (associated with changes in CaO2 ) as the primary biological regulator of CBF. The mechanisms for vasodilation therefore appear more robust during hypoxemic hypoxia than during changes in CaO2 via hemodilution. Clinical implications (e.g., disorders associated with anemia and polycythemia) and future study directions are considered. PMID:26676248

  9. Heterogeneity of muscarinic receptor subtypes in cerebral blood vessels

    SciTech Connect

    Garcia-Villalon, A.L.; Krause, D.N.; Ehlert, F.J.; Duckles, S.P. )

    1991-07-01

    The identity and distribution of muscarinic cholinergic receptor subtypes and associated signal transduction mechanisms was characterized for the cerebral circulation using correlated functional and biochemical investigations. Subtypes were distinguished by the relative affinities of a panel of muscarinic antagonists, pirenzepine, AF-DX 116 (11-2-((2-(diethylaminomethyl)- 1-piperidinyl)acetyl)-5,11-dihydro-6H- pyrido(2,3-b)(1,4)benzodiazepine-6-one), hexahydrosiladifenidol, methoctramine, 4-diphenylacetoxy-N-methylpiperidine methobromide, dicyclomine, para-fluoro-hexahydrosiladifenidol and atropine. Muscarinic receptors characterized by inhibition of (3H)quinuclidinylbenzilate binding in membranes of bovine pial arteries were of the M2 subtype. In contrast pharmacological analysis of (3H)-quinuclidinylbenzilate binding in bovine intracerebral microvessels suggests the presence of an M4 subtype. Receptors mediating endothelium-dependent vasodilation in rabbit pial arteries were of the M3 subtype, whereas muscarinic receptors stimulating endothelium-independent phosphoinositide hydrolysis in bovine pial arteries were of the M1 subtype. These findings suggest that characteristics of muscarinic receptors in cerebral blood vessels vary depending on the type of vessel, cellular location and function mediated.

  10. Altered Regional Cerebral Blood Flow in Chronic Whiplash Associated Disorders.

    PubMed

    Vállez García, David; Doorduin, Janine; Willemsen, Antoon T M; Dierckx, Rudi A J O; Otte, Andreas

    2016-08-01

    There is increasing evidence of central hyperexcitability in chronic whiplash-associated disorders (cWAD). However, little is known about how an apparently simple cervical spine injury can induce changes in cerebral processes. The present study was designed (1) to validate previous results showing alterations of regional cerebral blood flow (rCBF) in cWAD, (2) to test if central hyperexcitability reflects changes in rCBF upon non-painful stimulation of the neck, and (3) to verify our hypothesis that the missing link in understanding the underlying pathophysiology could be the close interaction between the neck and midbrain structures. For this purpose, alterations of rCBF were explored in a case-control study using H2(15)O positron emission tomography, where each group was exposed to four different conditions, including rest and different levels of non-painful electrical stimulation of the neck. rCBF was found to be elevated in patients with cWAD in the posterior cingulate and precuneus, and decreased in the superior temporal, parahippocampal, and inferior frontal gyri, the thalamus and the insular cortex when compared with rCBF in healthy controls. No differences in rCBF were observed between different levels of electrical stimulation. The alterations in regions directly involved with pain perception and interoceptive processing indicate that cWAD symptoms might be the consequence of a mismatch during the integration of information in brain regions involved in pain processing. PMID:27444853

  11. Experimental Arrest of Cerebral Blood Flow in Human Subjects

    PubMed Central

    Smith, Brian A.; Clayton, Ellen Wright; Robertson, David

    2013-01-01

    Loss of consciousness in pilots during rapid ascent after bombing missions was a major problem in World War II, and experiments were undertaken to study the cause of this phenomenon. Postulating impaired cerebral blood flow as a likely mechanism, the investigators developed a neck device, the KRA Cuff, which when inflated could shut off blood supply to the brain. With cessation of blood flow for up to 100 seconds, the investigators observed a sequence of responses, including unconsciousness, followed by dilated pupils, tonic/clonic movements, loss of bladder and eventually bowel control, and appearance of pathological reflexes. This study, carried out in prisoners and patients with schizophrenia in 1941–42, largely disappeared from public discourse for a number of years. It has received occasional attention subsequently and been considered controversial. Recently discovered records, including extensive written and photographic data from the studies, shed new light on the methods and motives of the research team. We describe here this new information and its implications for the scientific and ethical assessment of the study. PMID:21532128

  12. MRI of cerebral blood flow under hyperbaric conditions in rats.

    PubMed

    Cardenas, Damon P; Muir, Eric R; Duong, Timothy Q

    2016-07-01

    Hyperbaric oxygen (HBO) therapy has a number of clinical applications. However, the effects of acute HBO on basal cerebral blood flow (CBF) and neurovascular coupling are not well understood. This study explored the use of arterial spin labeling MRI to evaluate changes in baseline and forepaw stimulus-evoked CBF responses in rats (n = 8) during normobaric air (NB), normobaric oxygen (NBO) (100% O2 ), 3 atm absolute (ATA) hyperbaric air (HB) and 3 ATA HBO conditions. T1 was also measured, and the effects of changes in T1 caused by increasing oxygen on the CBF calculation were investigated. The major findings were as follows: (i) increased inhaled oxygen concentrations led to a reduced respiration rate; (ii) increased dissolved paramagnetic oxygen had significant effects on blood and tissue T1 , which affected the CBF calculation using the arterial spin labeling method; (iii) the differences in blood T1 had a larger effect than the differences in tissue T1 on CBF calculation; (iv) if oxygen-induced changes in blood and tissue T1 were not taken into account, CBF was underestimated by 33% at 3 ATA HBO, 10% at NBO and <5% at HB; (v) with correction, CBF values under HBO, HB and NBO were similar (p > 0.05) and all were higher than CBF under NB by ~40% (p < 0.05), indicating that hypercapnia from the reduced respiration rate masks oxygen-induced vasoconstriction, although blood gas was not measured; and (vi) substantial stimulus-evoked CBF increases were detected under HBO, similar to NB, supporting the notion that activation-induced CBF regulation in the brain does not operate through an oxygen-sensing mechanism. CBF MRI provides valuable insights into the effects of oxygen on basal CBF and neurovascular coupling under hyperbaric conditions. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27192391

  13. Portable real time analysis system for regional cerebral blood flow

    SciTech Connect

    Tiernan, T.; Entine, G.; Stump, D.A.; Prough, D.S.

    1988-02-01

    A very portable, regional cerebral blood flow (rCBF) analysis instrument system suitable for use in the operating theater during surgery is under development. Cadmium telluride (CdTe) solid state radiation detectors, an 8086 based data acquisition and communications module and a DEC Microvax computer are used so that the instrument is very compact, yet has the computational power to provide real time data analysis in the clinical environment. The instrument is currently being used at Bowman Gray School of Medicine to study rCBF during cardiopulmonary bypass surgery (CPB). Preliminary studies indicate that monitoring rCBF during this surgical procedure may provide insights into the mechanism that causes a significant fraction of these patients to suffer post operative neuropsychological deficit.

  14. Cerebral blood flow changes during vagus nerve stimulation for depression.

    PubMed

    Conway, Charles R; Sheline, Yvette I; Chibnall, John T; George, Mark S; Fletcher, James W; Mintun, Mark A

    2006-03-31

    Positron emission tomography (PET oxygen-15 labeled water or PET [15O]H2O) was used to identify changes in regional cerebral blood flow (rCBF) in response to acute vagus nerve stimulation (VNS) in four subjects with treatment-resistant major depression (TRMD). Four 90-s PET [15O]H2O scans were performed on each subject in an off-on sequence (2 VNS de-activated; 2 VNS activated). PET images were aligned, normalized for global uptake, and resampled to standard atlas space. Statistical t-images were used to evaluate change. VNS-induced increases in rCBF were found in the bilateral orbitofrontal cortex, bilateral anterior cingulate cortex, and right superior and medial frontal cortex. Decreases were found in the bilateral temporal cortex and right parietal area. Regions of change were consistent with brain structures associated with depression and the afferent pathways of the vagus nerve. PMID:16510266

  15. Optical coherence Doppler tomography for quantitative cerebral blood flow imaging

    PubMed Central

    You, Jiang; Du, Congwu; Volkow, Nora D.; Pan, Yingtian

    2014-01-01

    Optical coherence Doppler tomography (ODT) is a promising neurotechnique that permits 3D imaging of the cerebral blood flow (CBF) network; however, quantitative CBF velocity (CBFv) imaging remains challenging. Here we present a simple phase summation method to enhance slow capillary flow detection sensitivity without sacrificing dynamic range for fast flow and vessel tracking to improve angle correction for absolute CBFv quantification. Flow phantom validation indicated that the CBFv quantification accuracy increased from 15% to 91% and the coefficient of variation (CV) decreased 9.3-fold; in vivo mouse brain validation showed that CV decreased 4.4-/10.8- fold for venular/arteriolar flows. ODT was able to identify cocaine-elicited microischemia and quantify CBFv disruption in branch vessels and capillaries that otherwise would have not been possible. PMID:25401033

  16. Effect of hematocrit and systolic blood pressure on cerebral blood flow in newborn infants

    SciTech Connect

    Younkin, D.P.; Reivich, M.; Jaggi, J.L.; Obrist, W.D.; Delivoria-Papadopoulos, M.

    1987-06-01

    The effects of hematocrit and systolic blood pressure on cerebral blood flow were measured in 15 stable, low birth weight babies. CBF was measured with a modification of the xenon-133 (/sup 133/Xe) clearance technique, which uses an intravenous bolus of /sup 133/Xe, an external chest detector to estimate arterial /sup 133/Xe concentration, eight external cranial detectors to measure cephalic /sup 133/Xe clearance curves, and a two-compartmental analysis of the cephalic /sup 133/Xe clearance curves to estimate CBF. There was a significant inverse correlation between hematocrit and CBF, presumably due to alterations in arterial oxygen content and blood viscosity. Newborn CBF varied independently of systolic blood pressure between 60 and 84 mm Hg, suggesting an intact cerebrovascular autoregulatory mechanism. These results indicate that at least two of the factors that affect newborn animal CBF are operational in human newborns and may have important clinical implications.

  17. Cerebral blood flow during orthostasis: role of arterial CO2.

    PubMed

    Serrador, J M; Hughson, R L; Kowalchuk, J M; Bondar, R L; Gelb, A W

    2006-04-01

    Reductions in end-tidal Pco(2) (Pet(CO(2))) during upright posture have been suggested to be the result of hyperventilation and the cause of decreases in cerebral blood flow (CBF). The goal of this study was to determine whether decreases in Pet(CO(2)) reflected decreases in arterial Pco(2) (Pa(CO(2))) and their relation to increases in alveolar ventilation (Va) and decreases in CBF. Fifteen healthy subjects (10 women and 5 men) were subjected to a 10-min head-up tilt (HUT) protocol. Pa(CO(2)), Va, and cerebral flow velocity (CFV) in the middle and anterior cerebral arteries were examined. In 12 subjects who completed the protocol, reductions in Pet(CO(2)) and Pa(CO(2)) (-1.7 +/- 0.5 and -1.1 +/- 0.4 mmHg, P < 0.05) during minute 1 of HUT were associated with a significant increase in Va (+0.7 +/- 0.3 l/min, P < 0.05). However, further decreases in Pa(CO(2)) (-0.5 +/- 0.5 mmHg, P < 0.05), from minute 1 to the last minute of HUT, occurred even though Va did not change significantly (-0.2 +/- 0.3 l/min, P = not significant). Similarly, CFV in the middle and anterior cerebral arteries decreased (-7 +/- 2 and -8 +/- 2%, P < 0.05) from minute 1 to the last minute of HUT, despite minimal changes in Pa(CO(2)). These data suggest that decreases in Pet(CO(2)) and Pa(CO(2)) during upright posture are not solely due to increased Va but could be due to ventilation-perfusion mismatch or a redistribution of CO(2) stores. Furthermore, the reduction in Pa(CO(2)) did not fully explain the decrease in CFV throughout HUT. These data suggest that factors in addition to a reduction in Pa(CO(2)) play a role in the CBF response to orthostatic stress. PMID:16306163

  18. Cognitive impairment and gray matter volume abnormalities in silent cerebral infarction.

    PubMed

    Yang, Tao; Zhang, Lan; Xiang, Mingqing; Luo, Wei; Huang, Jinbai; Li, Maokun; Xiong, Xunbo; Wang, Hua

    2015-10-21

    To investigate the association between cognitive impairment and gray matter volume (GMV) abnormalities in silent cerebral infarction (SCI) patients, the GMV of 62 pairs of patients and well-matched healthy controls was calculated. All participants underwent a P300 test, a Montreal Cognitive Assessment (MoCA) test. Compared with controls, the patients showed decreased GMV in the left superior frontal gyrus, left inferior frontal gyrus, left superior temporal gyrus, right middle temporal gyrus, and bilateral parahippocampal gyrus; no significantly increasing GMV was found. The volumes of the frontal and temporal lobes were positively correlated with the score of the MoCA scale and P300 amplitudes (r≥0.62, P<0.01). The P300 latency was negatively correlated with the volumes of the frontal lobe, the temporal lobe, and the hippocampus (r≤-0.71, P<0.05). No significant correlations between the GMV of the abnormal brain regions and four clinical characteristics in SCI patients were found, suggesting that cognitive deficiency existed in SCI patients and the reduced GMV might contribute to the pathology of cognitive deficiency in SCI patients. PMID:26313037

  19. The influence of hyperoxia on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and cerebral blood flow velocity in the middle cerebral artery (CBFVMCA) in human volunteers.

    PubMed

    Kolbitsch, Christian; Lorenz, Ingo H; Hörmann, Christoph; Hinteregger, Martin; Löckinger, Alexander; Moser, Patrizia L; Kremser, Christian; Schocke, Michael; Felber, Stephan; Pfeiffer, Karl P; Benzer, Arnulf

    2002-09-01

    Conflicting results reported on the effects of hyperoxia on cerebral hemodynamics have been attributed mainly to methodical and species differences. In the present study contrast-enhanced magnetic resonance imaging (MRI) perfusion measurement was used to analyze the influence of hyperoxia (fraction of inspired oxygen (FiO2) = 1.0) on regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in awake, normoventilating volunteers (n = 19). Furthermore, the experiment was repeated in 20 volunteers for transcranial Doppler sonography (TCD) measurement of cerebral blood flow velocity in the middle cerebral artery (CBFV(MCA)). When compared to normoxia (FiO2 = 0.21), hyperoxia heterogeneously influenced rCBV (4.95 +/- 0.02 to 12.87 +/- 0.08 mL/100g (FiO2 = 0.21) vs. 4.50 +/- 0.02 to 13.09 +/- 0.09 mL/100g (FiO2 = 1.0). In contrast, hyperoxia diminished rCBF in all regions (68.08 +/- 0.38 to 199.58 +/- 1.58 mL/100g/min (FiO2 = 0.21) vs. 58.63 +/- 0.32 to 175.16 +/- 1.51 mL/100g/min (FiO2 = 1.0)) except in parietal and left frontal gray matter. CBFV(MCA) remained unchanged regardless of the inspired oxygen fraction (62 +/- 9 cm/s (FiO2 = 0.21) vs. 64 +/- 8 cm/s (FiO2 = 1.0)). Finding CBFV(MCA) unchanged during hyperoxia is consistent with the present study's unchanged rCBF in parietal and left frontal gray matter. In these fronto-parietal regions predominantly fed by the middle cerebral artery, the vasoconstrictor effect of oxygen was probably counteracted by increased perfusion of foci of neuronal activity controlling general behavior and arousal. PMID:12413599

  20. Cerebral hemodynamics in patients with moyamoya disease. A study of regional cerebral blood flow by the /sup 133/Xe inhalation method

    SciTech Connect

    Takeuchi, S.; Tanaka, R.; Ishii, R.; Tsuchida, T.; Kobayashi, K.; Arai, H.

    1985-05-01

    Regional cerebral blood flow was measured by the /sup 133/Xe inhalation method in 20 young patients with moyamoya disease and five young healthy volunteers. Most patients showed low values of mean hemispheric blood flow in both hemispheres. Regional cerebral blood flow was at a low value in the upper frontal region and at an almost average value in the posterotemporal and occipital regions, which was different from the ''hyperfrontal'' pattern in healthy volunteers. Regional cerebral blood flow was reduced evenly by hyperventilation. By 5% CO/sub 2/ inhalation, regional cerebral blood flow was increased in the temporooccipital regions and was nearly unchanged or decreased in the frontal region.

  1. A Modeling of Cerebral Blood Flow Changes due to Head Motion for fNIRS

    NASA Astrophysics Data System (ADS)

    Takahashi, Kosuke; Tanaka, Takayuki; Nara, Hiroyuki; Kaneko, Shun'ichi; Inoue, Masao; Shimizu, Shunji; Kojima, Satoru

    2013-04-01

    A method is proposed for measuring brain activity during exercises involving head motion by using functional near-infrared spectroscopy (fNIRS), which investigates cerebral hemodynamics. Obtaining measurements during exercise is difficult because cerebral blood flow changes due to the head motion component (HMC), in addition to neural activity. HMC is an undesirable artifact in the measurement of hemodynamic response caused by neural activity, and as such, it must be estimated and eliminated. In our experiments, cerebral blood flow and head motion were measured during repeated passive forward bending of the subjects. Head motion was measured by 3-D motion capture, and HMC was estimated by deriving a relation between head motion and cerebral blood flow, where the pitch angle was found to be suitable for estimating HMC. In this research, an assumption was made that cerebral blood flow caused by neural activity and that caused by postural change were additive, and thus HMC was eliminated by subtraction.

  2. Effect of acetazolamide on cerebral blood flow in subacute and chronic cerebrovascular disease

    SciTech Connect

    Hojer-Pedersen, E.

    1987-09-01

    Acetazolamide increases cerebral blood flow. The generalized and regional changes in blood flow after administration of acetazolamide were evaluated by the xenon-133 inhalation technique in a series of patients with subacute or chronic focal cerebral ischemia. Acetazolamide augmented interhemispheric asymmetry of cerebral blood flow in patients with unilateral occlusion of major cerebral arteries, whereas no significant side-to-side asymmetry was evident in patients with minor arterial lesions. Low flow areas in relation to computed tomography-verified infarcts tended to be larger after administration of acetazolamide. Hyperfrontality was present at rest and during stimulation with acetazolamide. A decline of cerebral blood flow with advancing age was greater in patients than in normal controls. The vasodilator response to acetazolamide did not change with age.

  3. Changes in the cerebral blood flow in newborn rats assessed by LSCI and DOCT before and after the hemorrhagic stroke

    NASA Astrophysics Data System (ADS)

    Semyachkina-Glushkovskaya, O. V.; Lychagov, V. V.; Abdurashitov, A. S.; Sindeeva, O. V.; Sindeev, S. S.; Zinchenko, E. M.; Kajbeleva, E. I.; Pavlov, A. N.; Kassim, M.; Tuchin, V. V.

    2015-03-01

    The incidence of perinatal hemorrhagic stroke (HS) is very similar to that in the elderly and produces a significant morbidity and long-term neurologic and cognitive deficits. There is strong evidence that cerebral blood flow (CBF) abnormalities make considerable contribution to HS development. However, the mechanisms responsible for pathological changes in CBF in infants with HS are not established. Therefore, quantitative assessment of CBF may significantly advance the understanding of the nature of neonatal stroke. The aim of this investigation was to determine the particularities of alterations in macro- microcirculation in the brain of newborn rats in the different stages of stress-related development of HS using three-dimensional Doppler optical coherence tomography (DOCT) and laser speckle contrast imaging (LSCI).Our results show that cerebral veins are more sensitive to harmful effect of stress compared with microcirculatory vessels. Stress-induced progressive dilation of cerebral veins with the fall of blood flow velocity precedes HS while pathological changes in microcirculatory vessels are accompanied by development of HS. The further detailed study of cerebral venous and microcirculatory circulation would be a significant advance in development of prognostic criteria for a HS risk during the first days after birthday.

  4. Dragon's blood dropping pills have protective effects on focal cerebral ischemia rats model.

    PubMed

    Xin, Nian; Yang, Fang-Ju; Li, Yan; Li, Yu-Juan; Dai, Rong-Ji; Meng, Wei-Wei; Chen, Yan; Deng, Yu-Lin

    2013-12-15

    Dragon's blood is a bright red resin obtained from Dracaena cochinchinensis (Lour.) S.C.Chen (Yunnan, China). As a traditional Chinese medicinal herb, it has great traditional medicinal value and is used for wound healing and to stop bleeding. Its main biological activity comes from phenolic compounds. In this study, phenolic compounds were made into dropping pills and their protective effects were examined by establishing focal cerebral ischemia rats model used method of Middle Cerebral Artery Occlusion (MCAO), and by investigating indexes of neurological scores, infarct volume, cerebral index, cerebral water content and oxidation stress. Compared to model group, high, middle and low groups of Dragon's blood dropping pills could improve the neurological function significantly (p<0.01) and reduce cerebral infarct volume of focal cerebral ischemia rats remarkably (p<0.05-0.01). Meanwhile, each group could alleviate cerebral water content and cerebral index (p<0.05-0.01) and regulate oxidative stress of focal cerebral ischemia rats obviously (p<0.05-0.01). Activities of middle group corresponded with that treated with positive control drug. The results obtained here showed that Dragon's blood dropping pills had protective effects on focal cerebral ischemia rats. PMID:24051215

  5. Cerebral blood flow velocity declines before arterial pressure in patients with orthostatic vasovagal presyncope

    NASA Technical Reports Server (NTRS)

    Dan, Dan; Hoag, Jeffrey B.; Ellenbogen, Kenneth A.; Wood, Mark A.; Eckberg, Dwain L.; Gilligan, David M.

    2002-01-01

    OBJECTIVES: We studied hemodynamic changes leading to orthostatic vasovagal presyncope to determine whether changes of cerebral artery blood flow velocity precede or follow reductions of arterial pressure. BACKGROUND: Some evidence suggests that disordered cerebral autoregulation contributes to the occurrence of orthostatic vasovagal syncope. We studied cerebral hemodynamics with transcranial Doppler recordings, and we closely examined the temporal sequence of changes of cerebral artery blood flow velocity and systemic arterial pressure in 15 patients who did or did not faint during passive 70 degrees head-up tilt. METHODS: We recorded photoplethysmographic arterial pressure, RR intervals (electrocardiogram) and middle cerebral artery blood flow velocities (mean, total, mean/RR interval; Gosling's pulsatility index; and cerebrovascular resistance [mean cerebral velocity/mean arterial pressure, MAP]). RESULTS: Eight men developed presyncope, and six men and one woman did not. Presyncopal patients reported light-headedness, diaphoresis, or a sensation of fatigue 155 s (range: 25 to 414 s) before any cerebral or systemic hemodynamic change. Average cerebral blood flow velocity (CBFV) changes (defined by an iterative linear regression algorithm) began 67 s (range: 9 to 198 s) before reductions of MAP. Cerebral and systemic hemodynamic measurements remained constant in nonsyncopal patients. CONCLUSIONS: Presyncopal symptoms and CBFV changes precede arterial pressure reductions in patients with orthostatic vasovagal syncope. Therefore, changes of cerebrovascular regulation may contribute to the occurrence of vasovagal reactions.

  6. Acute cocaine administration alters posttraumatic blood pressure and cerebral blood flow in rats.

    PubMed

    Muir, J K; Ellis, E F

    1995-01-01

    Cocaine abuse is widespread, and it is possible that its two main pharmacological actions, sympathomimetic and local anesthetic, could influence the blood pressure and cerebral blood flow response to brain injury, which occurs with increased frequency in drug abusers. We tested this hypothesis in ventilated barbiturate-anesthetized rats. Brain injury was induced using the fluid-percussion method, and cortical blood flow was measured using laser-Doppler flowmetry. Saline, cocaine, methamphetamine, or lidocaine was administered 10 min before injury. Upon injury, both cocaine- and saline-pretreated rats showed a similar acute hypertensive phase, which was followed by a period of more pronounced hypotension in the cocaine group (68 +/- 4 vs. 100 +/- 6 mmHg). Cortical blood flow increased dramatically 3-15 s following injury-induced hypertension in both the cocaine and saline groups (approximately 230-260%), but then fell below preinjury values within minutes. At 1 h postinjury, the blood flow in the saline group was 53 +/- 6% of the preinjury value, while in the cocaine group, flow was 74 +/- 7% of preinjury baseline. Similar to the cocaine-treated animals, methamphetamine also caused a more pronounced hypotensive event, but blood flow was not significantly different from saline controls. Lidocaine did not alter posttraumatic blood pressure but did significantly elevate blood flow throughout the 1-h postinjury period. At 60 min posttrauma, blood flow in the lidocaine group was 80 +/- 10% of the preinjury value. The mechanism by which cocaine alters blood pressure and blood flow after injury is not entirely certain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7840303

  7. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    SciTech Connect

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-06-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO/sub 2/ did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow.

  8. Effects of captopril on cerebral blood flow in normotensive and hypertensive rats

    SciTech Connect

    Barry, D.I.; Paulson, O.B.; Jarden, J.O.; Juhler, M.; Graham, D.I.; Strandgaard, S.

    1984-05-31

    Cerebrovascular effects of the angiotensin converting enzyme inhibitor captopril were examined in normotensive and hypertensive rats. Cerebral blood flow was measured with the intracarotid /sup 133/xenon injection method in halothane-anesthetized animals. The blood-brain barrier permeability of captopril (determined with an integral-uptake method) was negligible, the permeability-surface area product in most brain regions being 1 X 10(-5) cm3/g per second, that is, three to four times lower than that of sodium ion. When administered into the cerebral ventricles to bypass the blood-brain barrier, captopril had no effect on cerebral blood flow: furthermore, cerebral blood flow autoregulation (studied by raising and lowering blood pressure) was identical to that in controls. In contrast, when given intravenously, captopril had a marked effect on cerebral blood flow autoregulation--both the lower and upper limits of autoregulation being shifted to a lower pressure (by about 20 to 30 and 50 to 60 mm Hg, respectively), and the autoregulatory range was shortened by about 40 mm Hg. This effect may be ascribed to inhibition of converting enzyme in the cerebral blood vessels rather than within the brain.

  9. Conditional Tat protein brain expression in the GT-tg bigenic mouse induces cerebral fractional anisotropy abnormalities

    PubMed Central

    Carey, Amanda N.; Liu, Xiaoxu; Mintzopoulos, Dionyssios; Paris, Jason J.; McLaughlin, Jay P.; Kaufman, Marc J.

    2015-01-01

    Cerebral white matter changes including tissue water diffusion abnormalities detected with diffusion tensor magnetic resonance imaging (DTI) are commonly found in humans with Human Immunodeficiency Virus (HIV) infection, as well as in animal models of the disorder. The severities of some of these abnormalities have been reported to correlate with measures of disease progression or severity, or with the degree of cognitive dysfunction. Accordingly, DTI may be a useful translational biomarker. HIV-Tat protein appears to be an important factor in the viral pathogenesis of HIV-associated neurotoxicity. We previously reported cerebral gray matter density reductions in the GT-tg bigenic mouse treated with doxycycline (Dox) to conditionally induce Tat protein expression. Presently, we administered intraperitoneal (i.p.) Dox (100 mg/kg/day) for 7 days to GT-tg mice to determine whether induction of conditional Tat expression led to the development of cerebral DTI abnormalities. Perfused and fixed brains from eight GT-tg mice administered Dox and eight control mice administered saline i.p. were extracted and underwent DTI scans on a 9.4 Tesla scanner. A whole brain analysis detected fractional anisotropy (FA) reductions in several areas including insular and endopiriform regions, as well as within the dorsal striatum. These findings suggest that exposure to Tat protein is sufficient to induce FA abnormalities, and further support the use of the GT-tg mouse to model some effects of HIV. PMID:25619988

  10. Abnormal Myocardial Blood Flow Reserve Observed in Cardiac Amyloidosis

    PubMed Central

    Nel, Karen; Senior, Roxy; Greaves, Kim

    2016-01-01

    We performed real-time myocardial contrast echocardiography on a patient with cardiac amyloidosis and previous normal coronary angiography presenting with atypical chest pain to assess myocardial blood flow reserve (MBFR). Myocardial contrast echocardiography was performed and flash microbubble destruction and replenishment analysis was used to calculate myocardial blood flow. Dipyridamole was used to achieve hyperemia. MBFR was derived from the ratio of peak myocardial blood flow at hyperemia and rest. The results show a marked reduction in MBFR in our patient. Previous reports of luminal obstruction of intramyocardial rather than epicardial vessels by amyloid deposition may be causing microvascular dysfunction. PMID:27081447

  11. Adrenergic and prostanoid mechanisms in control of cerebral blood flow in hypotensive newborn pigs

    SciTech Connect

    Armstead, W.M.; Leffler, C.W.; Busija, D.W.; Beasley, D.G.; Mirro, R. )

    1988-04-01

    The interaction between adrenergic and prostanoid mechanisms in the control of cerebral hemodynamics in the conscious, hypotensive newborn pig was investigated. Pretreatment with the selective {alpha}{sub 1}- and {alpha}{sub 2}-adrenoceptor antagonists prazosin and yohimbine, respectively, had no effect on cerebral blood flow, calculated cerebral vascular resistance, or cerebral metabolic rate either before or after hemmorrhagic hypotension. Indomethacin treatment (5 mg/kg ia) of piglets following hemorrhage caused a significant decrease in blood flow to all brain regions within 20 min. This decrease in cerebral blood flow resulted from increased cerebral vascular resistances of 54 and 177%, 20 and 40 min after treatment, respectively. Cerebral oxygen consumption was reduced from 2.42 {+-} 0.28 to 1.45 {+-} 0.28 ml{center dot}100 g{sup {minus}1} and to 1.0 {+-} 0.28 ml{center dot}100 g{sup {minus}1}{center dot}min{sup {minus}1} 20 and 40 min after indomethacin, respectively, in hemorrhaged piglets. Decreases in cerebral blood flow and metabolic rate and increases in vascular resistance on treatment with indomethacin were the same as in animals pretreated with vehicle, prazosin, or yohimbine. These data are consistent with the hypothesis that the prostanoid system contributes to the maintenance of cerebral blood flow and cerebral metabolic rate during hypotension in the newborn, as reported previously. These data do not implicate removal of sympathetic modulation by prostanoids as a mechanism for indomethacin-induced cerebral vasoconstriction in hypotensive newborn piglets.

  12. Role of hypotension in decreasing cerebral blood flow in porcine endotoxemia

    SciTech Connect

    Miller, C.F.; Breslow, M.J.; Shapiro, R.M.; Traystman, R.J. )

    1987-10-01

    The role of reduced arterial blood pressure (MAP) in decreasing cerebral blood flow (CBF) during endotoxemia was studied in pentobarbital-anesthetized pigs. Microspheres were used to measure regional CBF changes during MAP manipulations in animals with and without endotoxin. Endotoxin decreased MAP to 50 mmHg and decreased blood flow to the cortex and cerebellum without affecting cerebral cortical oxygen consumption (CMRo{sub 2}). Elevating MAP from 50 to 70 mmHg during endotoxemia with norepinephrine did not change cortical blood flow or CMRo{sub 2} but increased cerebellar blood flow. Brain stem blood flow was not affected by endotoxin or norepinephrine. When MAP was decreased to 50 mmHg by hemorrhage without endotoxin, no change in blood flow to cortex, cerebellum, or brain stem was observed from base-line levels. These results suggest that decreased MAP below a lower limit for cerebral autoregulation does not account for the decreased CBF observed after endotoxin.

  13. Focal cerebral ischaemia in the rat: 2. Regional cerebral blood flow determined by (14C)iodoantipyrine autoradiography following middle cerebral artery occlusion

    SciTech Connect

    Tamura, A.; Graham, D.I.; McCulloch, J.; Teasdale, G.M.

    1981-01-01

    Local cerebral blood flow has been measured by quantitative autoradiography, employing (14C)iodoantipyrine as tracer, in rats killed half an hour after occlusion of the middle cerebral artery. The results were compared with pattern of local cerebral blood flow (CBF) in sham-operated rats and with neuropathological findings. In every animal there was a profound reduction (to 13% of control levels)in blood flow in the neocortex previously by the occluded artery. The level of blood flow in the areas in which ischaemic brain damage occurred was 0.24 +/- 0.03 ml g-1 min-1 (mean +/- SEM). this level of CBF is considerably greater than that reported following a similar surgical procedure in cats and primates. Moderate reductions in blood flow were also seen outside the territory of the occluded artery and in parts of the opposite hemisphere. Absolute increases in blood flow (hyperaemia) were seen only in the substantia nigra and globus pallidus ipsilateral to the occlusion. It is of the middle cerebral artery are reflections of alterations in neuronal function and metabolic activity secondary to the ischaemic lesion.

  14. SPECT study of cerebral blood flow reactivity after acetazolamide in patients with transient ischemic attacks

    SciTech Connect

    Chollet, F.; Celsis, P.; Clanet, M.; Guiraud-Chaumeil, B.; Rascol, A.; Marc-Vergnes, J.P.

    1989-04-01

    We investigated 15 patients with one or more transient ischemic attacks (TIAs) in the internal carotid artery territory within the month following the most recent TIA. Cerebral blood flow (CBF) was measured by single-photon emission computed tomography, using intravenous xenon-133 before and after injection of 1 g acetazolamide. Six patients had severe carotid stenosis or occlusion; the other nine patients had no significant carotid lesions. Twenty age-matched volunteers free of neurologic symptoms or history were used as controls. Mean CBF in the sylvian region was not significantly different between patients and controls. Seven patients exhibited a focal hypoperfusion at rest in the symptomatic hemisphere, and their hypoperfused areas were hyporeactive after administration of acetazolamide. Seven other patients exhibited hyporeactive areas after acetazolamide administration while their CBF tomograms at rest were normal. Thus, CBF abnormalities were detected in 14 of the 15 patients. Our findings suggest that CBF measured early after acetazolamide administration could be useful to confirm the clinical diagnosis of TIA. In the nine patients with no significant lesion of the internal carotid artery, the areas of hypoperfusion were small and were probably related to the focal ischemic event. In the six patients with severe lesions of the internal carotid artery, abnormalities were of variable size and intensity but were often large and pronounced. The discrepancy between these two subgroups of patients could be ascribed to the hemodynamic influence of the internal carotid artery lesions. Moreover, our findings may provide some insight into the pathophysiology of TIAs.

  15. Unveiling astrocytic control of cerebral blood flow with optogenetics

    PubMed Central

    Masamoto, Kazuto; Unekawa, Miyuki; Watanabe, Tatsushi; Toriumi, Haruki; Takuwa, Hiroyuki; Kawaguchi, Hiroshi; Kanno, Iwao; Matsui, Ko; Tanaka, Kenji F.; Tomita, Yutaka; Suzuki, Norihiro

    2015-01-01

    Cortical neural activities lead to changes in the cerebral blood flow (CBF), which involves astrocytic control of cerebrovascular tone. However, the manner in which astrocytic activity specifically leads to vasodilation or vasoconstriction is difficult to determine. Here, cortical astrocytes genetically expressing a light-sensitive cation channel, channelrhodopsin-2 (ChR2), were transcranially activated with a blue laser while the spatiotemporal changes in CBF were noninvasively monitored with laser speckle flowgraphy in the anesthetised mouse cortex. A brief photostimulation induced a fast transient increase in CBF. The average response onset time was 0.7 ± 0.7 sec at the activation foci, and this CBF increase spread widely from the irradiation spot with an apparent propagation speed of 0.8–1.1 mm/sec. The broad increase in the CBF could be due to a propagation of diffusible vasoactive signals derived from the stimulated astrocytes. Pharmacological manipulation showed that topical administration of a K+ channel inhibitor (BaCl2; 0.1–0.5 mM) significantly reduced the photostimulation-induced CBF responses, which indicates that the ChR2-evoked astrocytic activity involves K+ signalling to the vascular smooth muscle cells. These findings demonstrate a unique model for exploring the role of the astrocytes in gliovascular coupling using non-invasive, time-controlled, cell-type specific perturbations. PMID:26076820

  16. Functional laser speckle imaging of cerebral blood flow under hypothermia

    NASA Astrophysics Data System (ADS)

    Li, Minheng; Miao, Peng; Zhu, Yisheng; Tong, Shanbao

    2011-08-01

    Hypothermia can unintentionally occur in daily life, e.g., in cardiovascular surgery or applied as therapeutics in the neurosciences critical care unit. So far, the temperature-induced spatiotemporal responses of the neural function have not been fully understood. In this study, we investigated the functional change in cerebral blood flow (CBF), accompanied with neuronal activation, by laser speckle imaging (LSI) during hypothermia. Laser speckle images from Sprague-Dawley rats (n = 8, male) were acquired under normothermia (37°C) and moderate hypothermia (32°C). For each animal, 10 trials of electrical hindpaw stimulation were delivered under both temperatures. Using registered laser speckle contrast analysis and temporal clustering analysis (TCA), we found a delayed response peak and a prolonged response window under hypothermia. Hypothermia also decreased the activation area and the amplitude of the peak CBF. The combination of LSI and TCA is a high-resolution functional imaging method to investigate the spatiotemporal neurovascular coupling in both normal and pathological brain functions.

  17. Muscle metaboreflex and cerebral blood flow regulation in humans: implications for exercise with blood flow restriction.

    PubMed

    Prodel, Eliza; Balanos, George M; Braz, Igor D; Nobrega, Antonio C L; Vianna, Lauro C; Fisher, James P

    2016-05-01

    We investigated the effect of activating metabolically sensitive skeletal muscle afferents (muscle metaboreflex) on cerebral blood flow and the potentially confounding influence of concomitant changes in the partial pressure of arterial carbon dioxide. Eleven healthy males (25 ± 4 yr) performed submaximal leg cycling exercise on a semirecumbent cycle ergometer (heart rate: ∼120 beats/min), and assessments were made of the partial pressure of end-tidal carbon dioxide (PetCO2 ), internal carotid artery blood flow (ICAQ) and conductance (ICACVC), and middle cerebral artery mean blood velocity (MCAvm) and conductance index (MCACVCi).The muscle metaboreflex was activated during cycling with leg blood flow restriction (BFR) or isolated with postexercise ischemia (PEI). In separate trials, PetCO2 was either permitted to fluctuate spontaneously (control trial) or was clamped at 1 mmHg above resting levels (PetCO2 clamp trial). In the control trial, leg cycling with BFR decreased PetCO2 (Δ-4.8 ± 0.9 mmHg vs. leg cycling exercise) secondary to hyperventilation, while ICAQ, ICACVC, and MCAvm were unchanged and MCACVCi decreased. However, in the PetCO2 clamp trial, leg cycling with BFR increased both MCAvm (Δ5.9 ± 1.4 cm/s) and ICAQ (Δ20.0 ± 7.8 ml/min) and attenuated the decrease in MCACVCi, while ICACVC was unchanged. In the control trial, PEI decreased PetCO2 (Δ-7.0 ± 1.3 mmHg vs. rest), MCAvm and MCACVCi, whereas ICAQ and ICACVC were unchanged. In contrast, in the PetCO2 clamp trial both ICAQ (Δ18.5 ± 11.9 ml/min) and MCAvm (Δ8.8 ± 2.0 cm/s) were elevated, while ICACVC and MCACVCi were unchanged. In conclusion, when hyperventilation-related decreases in PetCO2 are prevented the activation of metabolically sensitive skeletal muscle afferent fibers increases cerebral blood flow. PMID:26873971

  18. Estimation of error limits for cerebral blood flow values obtained from xenon-133 clearance curves

    SciTech Connect

    Ryding, E.

    1989-02-01

    I provide the theoretical basis for an error calculus for measurements of cerebral blood flow using a freely diffusible tracer substance such as xenon-133. The use of the error calculus is exemplified by a study of the effect on the error margins in measurements of gray matter blood flow from flow level, relative weight of the gray matter compartment, and use of the earliest parts of the clearance curves. The clinical value of the error calculus is illustrated by its ability to separate different sources of measurement error. As a consequence, it is possible to optimize the method for blood flow calculation from the clearance curves, depending on the type of cerebral blood flow measurement. I show that if a true picture of the regional gray matter blood flow distribution is sought, the earliest part of the clearance curves should be used. This does, however, increase the error in the estimate of the average cerebral blood flow value.

  19. Longitudinal cerebral blood flow and amyloid deposition: an emerging pattern?

    PubMed Central

    Sojkova, Jitka; Beason-Held, Lori; Zhou, Yun; An, Yang; Kraut, Michael A; Ye, Weigo; Ferrucci, Luigi; Mathis, Chester A; Klunk, William E; Wong, Dean F; Resnick, Susan M

    2008-01-01

    Although cerebral amyloid deposition may precede cognitive impairment by decades, the relationship between amyloid deposition and longitudinal change in neuronal function has not been studied. The aim of this paper is to determine whether nondemented individuals with high and low amyloid burden show different patterns of longitudinal regional cerebral blood flow (rCBF) changes in the years preceding measurement of amyloid deposition. Methods Twenty-eight nondemented participants (mean (SD) age at [11C] PIB 82.5(4.8) yrs; 6 mildly impaired) from the Baltimore Longitudinal Study of Aging underwent yearly resting-state [15O]H2O PET scans for up to 8 years. [11C]PIB images of amyloid deposition were acquired on average 10.8(0.8) years after the first CBF scan. [11C]PIB distribution volume ratios (DVR) of regions of interest were estimated by fitting a reference tissue model to the measured time activity curves. Based on mean cortical DVR, participants were divided into high and low [11C]PIB retention groups. Differences in longitudinal rCBF changes between high and low [11C]PIB groups were investigated by voxel-based analysis. Results Longitudinal rCBF changes differed significantly between high (n=10) and low (n=18) [11C]PIB groups (p<=0.001). Greater longitudinal decreases in rCBF in the high [11C]PIB group were seen in right anterior/mid cingulate, right supramarginal gyrus, left thalamus and midbrain bilaterally relative to the low group. Greater increases in rCBF over time in the high [11C]PIB group were found in left medial and inferior frontal gyri, right precuneus, left inferior parietal lobule, and the left postcentral gyrus. Conclusion In this group of nondemented older adults, those with high [11C]PIB show greater longitudinal declines in rCBF in certain areas, representing regions with greater decrements in neuronal function. Greater longitudinal increases in rCBF are also observed in those with higher amyloid load and may represent an attempt to preserve

  20. Mechanisms of recovery from aphasia: evidence from serial xenon 133 cerebral blood flow studies

    SciTech Connect

    Knopman, D.S.; Rubens, A.B.; Selnes, O.A.; Klassen, A.C.; Meyer, M.W.

    1984-06-01

    In 21 patients who suffered aphasia resulting from left hemisphere ischemic infarction, the xenon 133 inhalation cerebral blood flow technique was used to measure cerebral blood flow within 3 months and 5 to 12 months after stroke. In addition to baseline measurements, cerebral blood flow measurements were also carried out while the patients were performing purposeful listening. In patients with incomplete recovery of comprehension and left posterior temporal-inferior parietal lesions, greater cerebral blood flow occurred with listening in the right inferior frontal region in the late studies than in the early studies. In patients with nearly complete recovery of comprehension and without left posterior temporal-inferior parietal lesions, early listening studies showed diffuse right hemisphere increases in cerebral blood flow. Later listening studies in this latter patient group showed greater cerebral blood flow in the left posterior temporal-inferior parietal region. The study provides evidence for participation of the right hemisphere in language comprehension in recovering aphasics, and for later return of function in left hemisphere regions that may have been functionally impaired early during recovery.

  1. Sympathetic regulation of cerebral blood flow during seizures in newborn lambs

    SciTech Connect

    Kurth, C.D.; Wagerle, L.C.; Delivoria-Papadopoulos, M. )

    1988-09-01

    The authors examined cerebral blood flow (CBF) regulation by the sympathetic nerves in 12 newborn lambs during seizures, a potent reflex stimulator of the sympathetic nervous system. CBF was measured with microspheres, and seizures were induced with bicuculline. In six of these lambs, one hemibrain was denervated (D) chronically by interrupting the ipsilateral cervical sympathetic trunk; the other hemibrain remained innervated (I). Before and after 10, 35, and 70 min of seizures, cerebral gray matter blood flow was measured. In the cerebral white matter, hippocampus, caudate, and thalamus blood flows to the D and I hemibrains were similar before seizures but during seizures they were 10-39% greater in the D than in the I hemibrain. Midbrain, brainstem, and cerebellum D and I blood flows were always similar. In the other six lambs, acute denervation during seizures increased ipsilateral cerebral gray and hippocampus blood flow by 10-31%, but unilateral electrical stimulation decreased ipsilateral cerebral gray, cerebral white, hippocampus, thalamus, and caudate blood flow by 17-27%. The data demonstrate that, during seizures, sympathetic nerve activity modifies regional CBF and the effect is sustained, suggesting a role for the sympathetic nervous system in newborn CBF regulation.

  2. Blood Pressure is Associated With Cerebral Blood Flow Alterations in Patients With T2DM as Revealed by Perfusion Functional MRI

    PubMed Central

    Xia, Wenqing; Rao, Hengyi; Spaeth, Andrea M.; Huang, Rong; Tian, Sai; Cai, Rongrong; Sun, Jie; Wang, Shaohua

    2015-01-01

    Abstract Type 2 diabetes mellitus (T2DM) and hypertension are both associated with cognitive impairment and brain function abnormalities. We investigated whether abnormal cerebral blood flow (CBF) patterns exists in T2DM patients and possible relationships between aberrant CBF and cognitive performance. Furthermore, we examined the influence of hypertension on CBF alterations in T2DM patients. T2DM patients (n = 38) and non-T2DM subjects (n = 40) were recruited from clinics, hospitals, and normal community health screenings. Cerebral blood flow images were collected and analyzed using arterial spin labeling perfusion functional magnetic resonance imaging (fMRI). Regions with major CBF differences between T2DM patients and non-T2DM controls were detected via 1-way ANOVA. The interaction effects between hypertension and T2DM for CBF alterations were also examined. Correlation analyses illustrated the association between CBF values and cognitive performance and between CBF and blood pressure. Compared with non-T2DM controls, T2DM patients exhibited decreased CBF, primarily in the visual area and the default mode network (DMN); decreased CBF in these regions was correlated with cognitive performance. There was a significant interaction effect between hypertension and diabetes for CBF in the precuneus and the middle occipital gyrus. Additionally, blood pressure correlated negatively with CBF in T2DM patients. T2DM patients exhibited reduced CBF in the visual area and DMN. Hypertension may facilitate a CBF decrease in the setting of diabetes. T2DM patients may benefit from blood pressure control to maintain their brain perfusion through CBF preservation. PMID:26632913

  3. Brain barrier properties and cerebral blood flow in neonatal mice exposed to cerebral hypoxia-ischemia

    PubMed Central

    Ek, C Joakim; D'Angelo, Barbara; Baburamani, Ana A; Lehner, Christine; Leverin, Anna-Lena; Smith, Peter LP; Nilsson, Holger; Svedin, Pernilla; Hagberg, Henrik; Mallard, Carina

    2015-01-01

    Insults to the developing brain often result in irreparable damage resulting in long-term deficits in motor and cognitive functions. The only treatment today for hypoxic-ischemic encephalopathy (HIE) in newborns is hypothermia, which has limited clinical benefit. We have studied changes to the blood–brain barriers (BBB) as well as regional cerebral blood flow (rCBF) in a neonatal model of HIE to further understand the underlying pathologic mechanisms. Nine-day old mice pups, brain roughly equivalent to the near-term human fetus, were subjected to hypoxia-ischemia. Hypoxia-ischemia increased BBB permeability to small and large molecules within hours after the insult, which normalized in the following days. The opening of the BBB was associated with changes to BBB protein expression whereas gene transcript levels were increased showing direct molecular damage to the BBB but also suggesting compensatory mechanisms. Brain pathology was closely related to reductions in rCBF during the hypoxia as well as the areas with compromised BBB showing that these are intimately linked. The transient opening of the BBB after the insult is likely to contribute to the pathology but at the same time provides an opportunity for therapeutics to better reach the infarcted areas in the brain. PMID:25627141

  4. Cerebral blood flow changes during sodium-lactate-induced panic attacks

    SciTech Connect

    Stewart, R.S.; Devous, M.D. Sr.; Rush, A.J.; Lane, L.; Bonte, F.J.

    1988-04-01

    Dynamic single-photon emission computed axial tomography (CAT) with inhaled xenon-133 was used to measure regional cerebral blood flow in 10 drug-free patients with DSM-III-diagnosed panic disorder and in five normal control subjects. All subjects underwent regional cerebral blood flow studies while at rest or during normal saline infusion and during sodium lactate infusion. Six of the 10 patients and none of the control subjects experienced lactate-induced panic attacks. Lactate infusion markedly raised hemispheric blood flow levels in both control subjects and patients who did not panic. Patients who did panic experienced either a minimal increase or a decrease in hemispheric blood flow.

  5. Reduced cerebral blood flow with orthostasis precedes hypocapnic hyperpnea, sympathetic activation, and postural tachycardia syndrome.

    PubMed

    Del Pozzi, Andrew T; Schwartz, Christopher E; Tewari, Deepali; Medow, Marvin S; Stewart, Julian M

    2014-06-01

    Hyperventilation and reduced cerebral blood flow velocity can occur in postural tachycardia syndrome (POTS). We studied orthostatically intolerant patients, with suspected POTS, with a chief complaint of upright dyspnea. On the basis of our observations of an immediate reduction of cerebral blood flow velocity with orthostasis, we hypothesize that the resulting ischemic hypoxia of the carotid body causes chemoreflex activation, hypocapnic hyperpnea, sympathetic activation, and increased heart rate and blood pressure in this subset of POTS. We compared 11 dyspneic POTS subjects with 10 healthy controls during a 70° head-up tilt. In POTS subjects during initial orthostasis before blood pressure recovery; central blood volume and mean arterial pressure were reduced (P<0.025), resulting in a significant (P<0.001) decrease in cerebral blood flow velocity, which temporally preceded (17±6 s; P<0.025) a progressive increase in minute ventilation and decrease in end tidal CO2 (P<0.05) when compared with controls. Sympathoexcitation, measured by muscle sympathetic nerve activity, was increased in POTS (P<0.01) and inversely proportional to end tidal CO2 and resulted in an increase in heart rate (P<0.001), total peripheral resistance (P<0.025), and a decrease in cardiac output (P<0.025). The decrease in cerebral blood flow velocity and mean arterial pressure during initial orthostasis was greater (P<0.025) in POTS. Our data suggest that exaggerated initial central hypovolemia during initial orthostatic hypotension in POTS results in reduced cerebral blood flow velocity and postural hypocapnic hyperpnea that perpetuates cerebral ischemia. We hypothesize that sustained hypocapnia and cerebral ischemia produce sympathoexcitation, tachycardia, and a statistically significant increase in blood pressure. PMID:24711524

  6. Relationship between blood pressure and cerebral blood flow during supine cycling: influence of aging.

    PubMed

    Smirl, Jonathan D; Hoffman, Keegan; Tzeng, Yu-Chieh; Hansen, Alex; Ainslie, Philip N

    2016-03-01

    The cerebral pressure-flow relationship can be quantified as a high-pass filter, where slow oscillations are buffered (<0.20 Hz) and faster oscillations are passed through relatively unimpeded. During moderate intensity exercise, previous studies have reported paradoxical transfer function analysis (TFA) findings (altered phase or intact gain). This study aimed to determine whether these previous findings accurately represent this relationship. Both younger (20-30 yr; n = 10) and older (62-72 yr; n = 9) adults were examined. To enhance the signal-to-noise ratio, large oscillations in blood pressure (via oscillatory lower body negative pressure; OLBNP) were induced during steady-state moderate intensity supine exercise (∼45-50% of heart rate reserve). Beat-to-beat blood pressure, cerebral blood velocity, and end-tidal Pco2 were monitored. Very low frequency (0.02-0.07 Hz) and low frequency (0.07-0.20 Hz) range spontaneous data were quantified. Driven OLBNP point estimates were sampled at 0.05 and 0.10 Hz. The OLBNP maneuvers augmented coherence to >0.97 at 0.05 Hz and >0.98 at 0.10 Hz in both age groups. The OLBNP protocol conclusively revealed the cerebrovascular system functions as a high-pass filter during exercise throughout aging. It was also discovered that the older adults had elevations (+71%) in normalized gain (+0.46 ± 0.36%/%: 0.05 Hz) and reductions (-34%) in phase (-0.24 ± 0.22 radian: 0.10 Hz). There were also age-related phase differences between resting and exercise conditions. It is speculated that these age-related changes in the TFA metrics are mediated by alterations in vasoactive factors, sympathetic tone, or the mechanical buffering of the compliance vessels. PMID:26586907

  7. Pediatric Sports-Related Concussion Produces Cerebral Blood Flow Alterations

    PubMed Central

    Farley, Chad; Altaye, Mekibib; Leach, James; Cecil, Kim M.

    2012-01-01

    Objectives: The pathophysiology of sports-related concussion (SRC) is incompletely understood. Human adult and experimental animal investigations have revealed structural axonal injuries, decreases in the neuronal metabolite N-acetyl aspartate, and reduced cerebral blood flow (CBF) after SRC and minor traumatic brain injury. The authors of this investigation explore these possibilities after pediatric SRC. Patients And Methods: Twelve children, ages 11 to 15 years, who experienced SRC were evaluated by ImPACT neurocognitive testing, T1 and susceptibility weighted MRI, diffusion tensor imaging, proton magnetic resonance spectroscopy, and phase contrast angiography at <72 hours, 14 days, and 30 days or greater after concussion. A similar number of age- and gender-matched controls were evaluated at a single time point. Results: ImPACT results confirmed statistically significant differences in initial total symptom score and reaction time between the SRC and control groups, resolving by 14 days for total symptom score and 30 days for reaction time. No evidence of structural injury was found on qualitative review of MRI. No decreases in neuronal metabolite N-acetyl aspartate or elevation of lactic acid were detected by proton magnetic resonance spectroscopy. Statistically significant alterations in CBF were documented in the SRC group, with reduction in CBF predominating (38 vs 48 mL/100 g per minute; P = .027). Improvement toward control values occurred in only 27% of the participants at 14 days and 64% at >30 days after SRC. Conclusions: Pediatric SRC is primarily a physiologic injury, affecting CBF significantly without evidence of measurable structural, metabolic neuronal or axonal injury. Further study of CBF mechanisms is needed to explain patterns of recovery. PMID:22129537

  8. The contribution of arterial blood gases in cerebral blood flow regulation and fuel utilization in man at high altitude.

    PubMed

    Willie, Christopher K; MacLeod, David B; Smith, Kurt J; Lewis, Nia C; Foster, Glen E; Ikeda, Keita; Hoiland, Ryan L; Ainslie, Philip N

    2015-05-01

    The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial-jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H(+) relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia. PMID:25690474

  9. The contribution of arterial blood gases in cerebral blood flow regulation and fuel utilization in man at high altitude

    PubMed Central

    Willie, Christopher K; MacLeod, David B; Smith, Kurt J; Lewis, Nia C; Foster, Glen E; Ikeda, Keita; Hoiland, Ryan L; Ainslie, Philip N

    2015-01-01

    The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial–jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H+ relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia. PMID:25690474

  10. Novel optoacoustic system for noninvasive continuous monitoring of cerebral venous blood oxygenation

    NASA Astrophysics Data System (ADS)

    Petrov, Yuriy; Petrov, Irene Y.; Prough, Donald S.; Esenaliev, Rinat O.

    2012-02-01

    Traumatic brain injury (TBI) and spinal cord injury are a major cause of death for individuals under 50 years of age. In the USA alone, 150,000 patients per year suffer moderate or severe TBI. Moreover, TBI is a major cause of combatrelated death. Monitoring of cerebral venous blood oxygenation is critically important for management of TBI patients because cerebral venous blood oxygenation below 50% results in death or severe neurologic complications. At present, there is no technique for noninvasive, accurate monitoring of this clinically important variable. We proposed to use optoacoustic technique for noninvasive monitoring of cerebral venous blood oxygenation by probing cerebral veins such as the superior sagittal sinus (SSS) and validated it in animal studies. In this work, we developed a novel, medical grade optoacoustic system for continuous, real-time cerebral venous blood oxygenation monitoring and tested it in human subjects at normal conditions and during hyperventilation to simulate changes that may occur in patients with TBI. We designed and built a highly-sensitive optoacoustic probe for SSS signal detection. Continuous measurements were performed in the near infrared spectral range and the SSS oxygenation absolute values were automatically calculated in real time using a special algorithm developed by our group. Continuous measurements performed at normal conditions and during hyperventilation demonstrated that hyperventilation resulted in approximately 12% decrease of cerebral venous blood oxygenation.

  11. REDUCED CEREBRAL BLOOD FLOW WITH ORTHOSTASIS PRECEDES HYPOCAPNIC HYPERPNEA, SYMPATHETIC ACTIVATION AND POTS

    PubMed Central

    Del Pozzi, Andrew T.; Schwartz, Christopher E.; Tewari, Deepali; Medow, Marvin S.; Stewart, Julian M.

    2014-01-01

    Hyperventilation, and reduced cerebral blood flow velocity can occur in postural tachycardia syndrome (POTS). We studied orthostatically intolerant patients, with suspected POTS, with a chief complaint of upright dyspnea. Based on our observations of an immediate reduction of cerebral blood flow velocity with orthostasis, we hypothesize that the resulting ischemic hypoxia of the carotid body causes chemoreflex activation, hypocapnic hyperpnea, sympathetic activation, and increased heart rate and blood pressure in this subset of POTS. We compared 11 dyspneic POTS subjects to 10 healthy controls during a 70° head-up tilt. In POTS subjects during initial orthostasis prior to BP recovery; central blood volume and mean arterial pressure were reduced (P<0.025) resulting in a significant (P<0.001) decrease in cerebral blood flow velocity, which temporally preceded (17±6 s; P<0.025) a progressive increase in minute ventilation and decrease in end tidal CO2 (P<0.05), compared to controls. Sympathoexcitation, measured by muscle sympathetic nerve activity, was increased in POTS, (P<0.01), and inversely proportional to end tidal CO2 and resulted in an increase in heart rate, (P<0.001), total peripheral resistance (P<0.025), and a decrease in cardiac output (P<0.025). The decrease in cerebral blood flow velocity and mean arterial pressure during initial orthostasis was greater (P<0.025) in POTS. Our data suggest that exaggerated initial central hypovolemia during initial orthostatic hypotension in POTS results in reduced cerebral blood flow velocity and postural hypocapnic hyperpnea that perpetuates cerebral ischemia. We hypothesize that sustained hypocapnia and cerebral ischemia produce sympathoexcitation, tachycardia and a statistically significant increase in blood pressure. PMID:24711524

  12. The influence of the non-Newtonian properties of blood on blood-hammer through the posterior cerebral artery.

    PubMed

    Tazraei, Pedram; Riasi, Alireza; Takabi, Behrouz

    2015-06-01

    This work investigates a two dimensional numerical analysis of blood hammer through the posterior cerebral artery. The non-Newtonian and usual Newtonian blood models are compared in the case of blood hammer through the posterior cerebral artery to quantify the differences between the models. In this way, a validated CFD simulation is used to study non-Newtonian shear-thinning effects of blood. The governing equations for the modeling of two-dimensional transient flow are solved using a combination of characteristics and central finite difference methods, respectively for the hyperbolic and parabolic parts. Herein, the non-Newtonian viscosity characteristic of blood is incorporated by using the Carreau model. To convert the nonlinear terms available in the characteristics equation into the linear ones, the Newton-Kantorovich method is implemented. The verification and validation of the numerical results are carried out in detail. Hemodynamic characteristics of blood hammer through the posterior cerebral artery are derived with both the Newtonian and non-Newtonian models, and the results are meticulously compared and discussed. The results show that when blood hammer occurs, the non-Newtonian properties greatly influence the velocity and shear stress profiles. At the early stages of blood hammer, there is a 64% difference between magnitudes of wall shear stress in these two models, and the magnitude of the wall shear stress for the shear-thinning blood flow is lower than the Newtonian one. PMID:25865933

  13. Blood gases and energy metabolites in mouse blood before and after cerebral ischemia: the effects of anesthetics.

    PubMed

    Schwarzkopf, Tina M; Horn, Tobias; Lang, Dorothee; Klein, Jochen

    2013-01-01

    The levels of blood gases and energy metabolites strongly influence the outcome of animal experiments, for example in experimental stroke research. While mice have become prominent animal models for cerebral ischemia, little information is available on the effects of anesthetic drugs on blood parameters such as blood gases, glucose and lactate in this species. In this work, we collected arterial and venous blood samples from female CD-1 mice before and after cerebral ischemia induced by middle cerebral artery occlusion (MCAO), and we tested the influence of different anesthetic drugs. We found that all of the injectable anesthetics tested (ketamine/xylazine, chloral hydrate, propofol and pentobarbital) caused a decrease in blood pH and partial pressure of oxygen (pO2) and an increase of partial pressure of carbon dioxide (pCO2), indicating respiratory depression. This was not observed with inhalable anesthetics such as isoflurane, sevoflurane and halothane. Significant and up to two-fold increases of blood glucose concentration were observed under isoflurane, halothane, ketamine/xylazine, chloral hydrate, and propofol anesthesia. Lactate concentration rose significantly by 2-3-fold during inhalation of isoflurane and halothane treatment, but decreased by more than 50% after administration of pentobarbital. Permanent cerebral ischemia induced respiratory acidosis (low pH and pO2, high pCO2) which was most prominent after 24 h. Postsurgical treatment with Ringer-lactate solution (1 mL, intraperitoneal) caused a recovery of blood gases to basal levels after 24 h. Use of isoflurane for surgery caused a minor increase of blood glucose concentrations after one hour, but a strong increase of blood lactate. In contrast, anesthesia with pentobarbital did not affect glucose concentration but strongly reduced blood lactate concentrations one hour after surgery. All values recovered at three hours after MCAO. In conclusion, anesthetic drugs have a strong influence on murine

  14. Traumatic Brain Injury by a Closed Head Injury Device Induces Cerebral Blood Flow Changes and Microhemorrhages

    PubMed Central

    Kallakuri, Srinivasu; Bandaru, Sharath; Zakaria, Nisrine; Shen, Yimin; Kou, Zhifeng; Zhang, Liying; Haacke, Ewart Mark; Cavanaugh, John M

    2015-01-01

    Objectives: Traumatic brain injury is a poly-pathology characterized by changes in the cerebral blood flow, inflammation, diffuse axonal, cellular, and vascular injuries. However, studies related to understanding the temporal changes in the cerebral blood flow following traumatic brain injury extending to sub-acute periods are limited. In addition, knowledge related to microhemorrhages, such as their detection, localization, and temporal progression, is important in the evaluation of traumatic brain injury. Materials and Methods: Cerebral blood flow changes and microhemorrhages in male Sprague Dawley rats at 4 h, 24 h, 3 days, and 7 days were assessed following a closed head injury induced by the Marmarou impact acceleration device (2 m height, 450 g brass weight). Cerebral blood flow was measured by arterial spin labeling. Microhemorrhages were assessed by susceptibility-weighted imaging and Prussian blue histology. Results: Traumatic brain injury rats showed reduced regional and global cerebral blood flow at 4 h and 7 days post-injury. Injured rats showed hemorrhagic lesions in the cortex, corpus callosum, hippocampus, and brainstem in susceptibility-weighted imaging. Injured rats also showed Prussian blue reaction products in both the white and gray matter regions up to 7 days after the injury. These lesions were observed in various areas of the cortex, corpus callosum, hippocampus, thalamus, and midbrain. Conclusions: These results suggest that changes in cerebral blood flow and hemorrhagic lesions can persist for sub-acute periods after the initial traumatic insult in an animal model. In addition, microhemorrhages otherwise not seen by susceptibility-weighted imaging are present in diverse regions of the brain. The combination of altered cerebral blood flow and microhemorrhages can potentially be a source of secondary injury changes following traumatic brain injury and may need to be taken into consideration in the long-term care of these cases. PMID:26605126

  15. Enhanced global mathematical model for studying cerebral venous blood flow.

    PubMed

    Müller, Lucas O; Toro, Eleuterio F

    2014-10-17

    Here we extend the global, closed-loop, mathematical model for the cardiovascular system in Müller and Toro (2014) to account for fundamental mechanisms affecting cerebral venous haemodynamics: the interaction between intracranial pressure and cerebral vasculature and the Starling-resistor like behaviour of intracranial veins. Computational results are compared with flow measurements obtained from Magnetic Resonance Imaging (MRI), showing overall satisfactory agreement. The role played by each model component in shaping cerebral venous flow waveforms is investigated. Our results are discussed in light of current physiological concepts and model-driven considerations, indicating that the Starling-resistor like behaviour of intracranial veins at the point where they join dural sinuses is the leading mechanism. Moreover, we present preliminary results on the impact of neck vein strictures on cerebral venous hemodynamics. These results show that such anomalies cause a pressure increment in intracranial cerebral veins, even if the shielding effect of the Starling-resistor like behaviour of cerebral veins is taken into account. PMID:25169660

  16. Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations.

    PubMed

    Hilz, Max J; Wang, Ruihao; Marthol, Harald; Liu, Mao; Tillmann, Alexandra; Riss, Stephan; Hauck, Paulina; Hösl, Katharina M; Wasmeier, Gerald; Stemper, Brigitte; Köhrmann, Martin

    2016-06-15

    Cerebral autoregulation (CA) dampens transfer of blood pressure (BP)-fluctuations onto cerebral blood flow velocity (CBFV). Thus, CBFV-oscillations precede BP-oscillations. The phase angle (PA) between sympathetically mediated low-frequency (LF: 0.03-0.15Hz) BP- and CBFV-oscillations is a measure of CA quality. To evaluate whether PA depends on sympathetic modulation, we assessed PA-changes upon sympathetic stimulation with and without pharmacologic sympathetic blockade. In 10 healthy, young men, we monitored mean BP and CBFV before and during 120-second cold pressor stimulation (CPS) of one foot (0°C ice-water). We calculated mean values, standard deviations and sympathetic LF-powers of all signals, and PAs between LF-BP- and LF-CBFV-oscillations. We repeated measurements after ingestion of the adrenoceptor-blocker carvedilol (25mg). We compared parameters before and during CPS, without and after carvedilol (analysis of variance, post-hoc t-tests, significance: p<0.05). Without carvedilol, CPS increased BP, CBFV, BP-LF- and CBFV-LF-powers, and shortened PA. Carvedilol decreased resting BP, CBFV, BP-LF- and CBFV-LF-powers, while PAs remained unchanged. During CPS, BPs, CBFVs, BP-LF- and CBFV-LF-powers were lower, while PAs were longer with than without carvedilol. With carvedilol, CPS no longer shortened resting PA. Sympathetic activation shortens PA. Partial adrenoceptor blockade abolishes this PA-shortening. Thus, PA-measurements provide a subtle marker of sympathetic influences on CA and might refine CA evaluation. PMID:27206903

  17. The Effect of Acetazolamide on Cerebral Blood Flow and Oxygen Utilization in the Rhesus Monkey

    PubMed Central

    Laux, B. E.; Raichle, M. E.

    1978-01-01

    The brain is critically dependent for its moment to moment function and survival on an adequate supply of oxygen. The enzyme carbonic anhydrase (EC 4.2.1.1) may play an important role in oxygen delivery to brain tissue by facilitating the hydration of metabolically produced carbon dioxide in erythrocytes in brain capillaries, thus permitting the Bohr effect to occur. We examined the effect of 30 mg/kg i.v. acetazolamide, a potent inhibitor of carbonic anhydrase, upon cerebral blood flow and oxygen consumption in lightly anesthetized, passively ventilated rhesus monkeys. Cerebral blood flow and oxygen consumption were measured with oxygen-15-labeled water and oxygen-15-labeled oxyhemoglobin, respectively, injected into the internal carotid artery and monitored externally. Acetazolamide produced an immediate and significant increase in cerebral blood flow (from a mean of 64.7 to 83.8 ml/100 g per min), an increase in arterial carbon dioxide tension (from a mean of 40.7 to 47.5 torr), and a decrease in cerebral oxygen consumption (from a mean of 4.16 to 2.82 ml/100 g per min). Because the change in cerebral oxygen consumption occurred within minutes of the administration of acetazolamide, we believe that this effect probably was not due to a direct action on brain cells but was achieved by an interference with oxygen unloading in brain capillaries. A resultant tissue hypoxia might well explain part of the observed increase in cerebral blood flow. PMID:99455

  18. Increased cerebral blood flow during hypercapnia is not affected by lesion of the nucleus locus ceruleus

    SciTech Connect

    Harik, S.I.; Prado, R.; Busto, R.; Ginsberg, M.D.

    1986-11-01

    To test the hypothesis that the putative noradrenergic innervation of intraparenchymal cerebral blood vessels from the nucleus locus ceruleus mediates the vasodilatory response to hypercapnia, regional cerebral blood flow was measured by iodo-(/sup 14/C)antipyrine autoradiography in awake and restrained rats with unilateral 6-hydroxydopamine lesion of the nucleus locus ceruleus and in unlesioned control rats. Hypercapnia, induced by the inhalation of 5% or 8% CO/sub 2/ in air for 8 minutes caused a 2 to 5-fold increase in regional cerebral blood flow. However, despite a marked reduction of about 90% in cortical norepinephrine levels ipsilateral to the lesion, blood flow to the frontal and parietal cortex, hippocampus, striatum and cerebellum increased to the same extent in ipsilateral and contralateral regions. Thus, lesion of the locus ceruleus and the resultant depletion of endogenous cortical and hippocampal norepinephrine, does not influence the cerebrovascular response to hypercapnia.

  19. Aerobic fitness is associated with greater hippocampal cerebral blood flow in children.

    PubMed

    Chaddock-Heyman, Laura; Erickson, Kirk I; Chappell, Michael A; Johnson, Curtis L; Kienzler, Caitlin; Knecht, Anya; Drollette, Eric S; Raine, Lauren B; Scudder, Mark R; Kao, Shih-Chun; Hillman, Charles H; Kramer, Arthur F

    2016-08-01

    The present study is the first to investigate whether cerebral blood flow in the hippocampus relates to aerobic fitness in children. In particular, we used arterial spin labeling (ASL) perfusion MRI to provide a quantitative measure of blood flow in the hippocampus in 73 7- to 9-year-old preadolescent children. Indeed, aerobic fitness was found to relate to greater perfusion in the hippocampus, independent of age, sex, and hippocampal volume. Such results suggest improved microcirculation and cerebral vasculature in preadolescent children with higher levels of aerobic fitness. Further, aerobic fitness may influence how the brain regulates its metabolic demands via blood flow in a region of the brain important for learning and memory. To add specificity to the relationship of fitness to the hippocampus, we demonstrate no significant association between aerobic fitness and cerebral blood flow in the brainstem. Our results reinforce the importance of aerobic fitness during a critical period of child development. PMID:27419884

  20. Cerebral Blood Flow Response to Hypercapnia in Children with Obstructive Sleep Apnea Syndrome

    PubMed Central

    Busch, David R.; Lynch, Jennifer M.; Winters, Madeline E.; McCarthy, Ann L.; Newland, John J.; Ko, Tiffany; Cornaglia, Mary Anne; Radcliffe, Jerilynn; McDonough, Joseph M.; Samuel, John; Matthews, Edward; Xiao, Rui; Yodh, Arjun G.; Marcus, Carole L.; Licht, Daniel J.; Tapia, Ignacio E.

    2016-01-01

    Study Objectives: Children with obstructive sleep apnea syndrome (OSAS) often experience periods of hypercapnia during sleep, a potent stimulator of cerebral blood flow (CBF). Considering this hypercapnia exposure during sleep, it is possible that children with OSAS have abnormal CBF responses to hypercapnia even during wakefulness. Therefore, we hypothesized that children with OSAS have blunted CBF response to hypercapnia during wakefulness, compared to snorers and controls. Methods: CBF changes during hypercapnic ventilatory response (HCVR) were tested in children with OSAS, snorers, and healthy controls using diffuse correlation spectroscopy (DCS). Peak CBF changes with respect to pre-hypercapnic baseline were measured for each group. The study was conducted at an academic pediatric sleep center. Results: Twelve children with OSAS (aged 10.1 ± 2.5 [mean ± standard deviation] y, obstructive apnea hypopnea index [AHI] = 9.4 [5.1–15.4] [median, interquartile range] events/hour), eight snorers (11 ± 3 y, 0.5 [0–1.3] events/hour), and 10 controls (11.4 ± 2.6 y, 0.3 [0.2–0.4] events/hour) were studied. The fractional CBF change during hypercapnia, normalized to the change in end-tidal carbon dioxide, was significantly higher in controls (9 ± 1.8 %/mmHg) compared to OSAS (7.1 ± 1.5, P = 0.023) and snorers (6.7 ± 1.9, P = 0.025). Conclusions: Children with OSAS and snorers have blunted CBF response to hypercapnia during wakefulness compared to controls. Noninvasive DCS blood flow measurements of hypercapnic reactivity offer insights into physiopathology of OSAS in children, which could lead to further understanding about the central nervous system complications of OSAS. Citation: Busch DR, Lynch JM, Winters ME, McCarthy AL, Newland JJ, Ko T, Cornaglia MA, Radcliffe J, McDonough JM, Samuel J, Matthews E, Xiao R, Yodh AG, Marcus CL, Licht DJ, Tapia IE. Cerebral blood flow response to hypercapnia in children with obstructive sleep apnea syndrome. SLEEP 2016

  1. Pulsed arterial spin labeling effectively and dynamically observes changes in cerebral blood flow after mild traumatic brain injury

    PubMed Central

    Peng, Shu-ping; Li, Yi-ning; Liu, Jun; Wang, Zhi-yuan; Zhang, Zi-shu; Zhou, Shun-ke; Tao, Fang-xu; Zhang, Zhi-xue

    2016-01-01

    Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient's condition and judging prognosis after traumatic brain injury. PMID:27073378

  2. Single-photon tomographic determination of regional cerebral blood flow in psychiatric disorders

    SciTech Connect

    Devous, M.D. Sr.; Rush, A.J.; Schlesser, M.A.; Debus, J.; Raese, J.D.; Chehabi, H.H.; Bonte, F.J.

    1984-01-01

    Regional cerebral blood flow (rCBF) was measured by single-photon emission computed tomography (SPECT) of 133-Xe washout in 29 normal volunteers, 22 unipolar endogenous depressives (UPE), 9 unipolar nonendogenous depressives (UPNE), 13 bipolar depressed patients (BPD), and 14 schizophrenic patients (SCHZ). RCBF was measured 2 and 6 cm above and parallel to the cantho-meatal line and quantitated in 14 gray matter regions. Most subjects were drug-free for 4-14 days. Diagnoses were made by experienced clinicians employing the Research Diagnostic Criteria, the Hamilton Rating Scale, and the dexamethasone suppression test. SCHZ were rated with the Brief Psychiatric Rating Scale. UPE had reduced flow compared to normals in the right parietal and temporal lobes and a nonsignificant trend toward left temporal flow reductions. UPNE were not different from normal or other patient groups. BPD had significant flow elevations in the left hemisphere relative to normal, and in both hemispheres relative to UPE. SCHZ were not significantly different from normal or other patient groups. Anterior-posterior flow shifts were evaluated by subtracting parietal or temporal flows from frontal flows. SCHZ demonstrated a greater posterior shift (lower relative frontal lobe flow) in comparison to both UPE and UPNE. The most significant regional flow abnormalities were observed as frontal flow reductions in individual SCHZ, although these were not significant in the whole group in comparison to normal.

  3. Interictal regional cerebral blood flow during non specific activation test in partial epilepsy.

    PubMed Central

    Valmier, J; Touchon, J; Baldy-Moulinier, M

    1989-01-01

    In order to investigate, during activation testing, the interictal cortical cerebral blood flows (rCBF) of epileptic patients suffering from complex partial seizures, 40 epileptic patients (divided into "lesional", this is, with abnormal CT findings, and "non lesional", that is, with normal CT findings) were submitted to rCBF measurements with the 133 xenon intravenous technique, at rest and during intermittent light stimulation (ILS). The findings compared with normal volunteers seem to demonstrate that, during ILS, (1) in non lesional patients, the suspected epileptic focus shows a significant rCBF increase (2) in lesional patients, the significant rCBF increases were not in the region of the suspected epileptic focus but in adjacent or in contralateral ones. It was concluded that activation interictal rCBF measurements are more useful than resting ones for the determination of epileptic foci when CT findings are normal and that the nature of the epileptic focus influences markedly the interhemispheric activation pattern. PMID:2926422

  4. Human Umbilical Cord Blood Cells Ameliorates Motor Deficits In Rabbits In a Cerebral Palsy Model

    PubMed Central

    Drobyshevsky, A.; Cotten, C. M.; Shi, Z.; Luo, K.; Jiang, R.; Derrick, M.; Tracy, E. T.; Gentry, T.; Goldberg, R. N.; Kurtzberg, J.; Tan, S.

    2015-01-01

    Cerebral palsy (CP) has significant impact on both patients and society but therapy is limited. Human umbilical cord blood cells (HUCBC), containing various stem and progenitor cells, have been used to treat various brain genetic conditions. In small animal experiments, HUCBC have improved outcomes after hypoxic-ischemic injury. Clinical trials using HUCBC are underway testing feasibility, safety and efficacy for neonatal injury as well as CP. We tested HUCBC therapy in a validated rabbit model of CP after acute changes secondary to hypoxic-ischemic (H-I) injury had subsided. Following uterine ischemia at 70% gestation, we infused HUCBC to newborn rabbit kits with either mild or severe neurobehavioral changes. Infusion of high dose HUCBC, 5x106 cells, dramatically altered the natural history of the injury alleviating the abnormal phenotype including posture, righting reflex, locomotion, tone, and dystonia. Half the high dose showed lesser but still significant improvement. The swimming test however showed that joint function did not restore to naïve control function in either group. Tracing HUCBCs with either MRI biomarkers or PCR for human DNA found little penetration of HUCBC in the newborn brain in the immediate newborn period, suggesting that the beneficial effects were not due to cellular integration or direct proliferative effects but rather to paracrine signaling. This is the first study to show that HUCBC improve motor performance in a dose-dependent manner perhaps by improving compensatory repair processes. PMID:25791742

  5. Effects of video game playing on cerebral blood flow in young adults: a SPECT study.

    PubMed

    Chou, Yuan-Hwa; Yang, Bang-Hung; Hsu, Ju-Wei; Wang, Shyh-Jen; Lin, Chun-Lung; Huang, Kai-Lin; Chien Chang, Alice; Lee, Shin-Min

    2013-04-30

    To study the impact of video game playing on the human brain, the effects of two video games playing on cerebral blood flow (CBF) in young adults were determined. Thirty healthy subjects comprising 18 males and 12 females who were familiar with video game playing were recruited. Each subject underwent three sessions of single photon emission computed tomography (SPECT) with a bolus injection of 20 mCi (99m)Tc ECD IV to measure their CBF. The first measurement was performed as baseline, the second and third measurements were performed after playing two different video games for 30 min, respectively. Statistic parametric mapping (SPM2) with Matlab 6.5 implemented on a personal computer was used for image analysis. CBF was significantly decreased in the prefrontal cortex and significantly increased in the temporal and occipital cortices after both video games playing. Furthermore, decreased CBF in the anterior cingulate cortex (ACC) which was significantly correlated with the number of killed characters was found after the violent game playing. The major finding of hypo-perfusion in prefrontal regions after video game playing is consistent with a previous study showing reduced or abnormal prefrontal cortex functions after video game playing. The second finding of decreased CBF in the ACC after playing the violent video game provides support for a previous hypothesis that the ACC might play a role in regulating violent behavior. PMID:23137807

  6. Cerebral blood velocity and other cardiovascular responses to 2 days of head-down tilt

    NASA Technical Reports Server (NTRS)

    Frey, Mary A. B.; Mader, Thomas H.; Bagian, James P.; Charles, John B.; Meehan, Richard T.

    1993-01-01

    Spaceflight induces a cephalad redistribution of fluid volume and blood flow within the human body, and space motion sickness, which is a problem during the first few days of space flight, could be related to these changes in fluid status and in blood flow of the cerebrum and vestibular system. To evaluate possible changes in cerebral blood flow during simulated weightlessness, we measured blood velocity in the middle cerebral artery (MCA) along with retinal vascular diameters, intraocular pressure, impedance cardiography, and sphygmomanometry on nine men (26.2 +/- 6.6 yr) morning and evening for 2 days during continuous 10 deg head-down tilt (HDT). When subjects went from seated to head-down bed rest, their heart rate and retinal diameters decreased, and intraocular pressures increased. After 48 h of HDT, blood flow velocity in the MCA was decreased and thoracic impedance was increased, indicating less fluid in the thorax. Percent changes in blood flow velocities in the MCA after 48 h of HDT were inversely correlated with percent changes in retinal vascular diameters. Blood flow velocities in the MCA were inversely correlated (intersubject) with arterial pressures and retinal vascular diameters. Heart rate, stroke volume, cardiac output, systolic arterial pressure, and at times pulse pressure and blood flow velocities in the MCA were greater in the evening. Total peripheral resistance was higher in the morning. Although cerebral blood velocity is reduced after subjects are head down for 2 days, the inverse relationship with retinal vessel diameters, which have control analogous to that of cerebral vessels, indicates cerebral blood flow is not reduced.

  7. Problems in cerebral blood flow calculation using xenon-133 in patients with pulmonary diseases

    SciTech Connect

    Hansen, M.; Jakobsen, M.; Enevoldsen, E.; Egede, F. )

    1990-05-01

    We used the end-tidal concentration of xenon-133 (air curve) to estimate the profile of its arterial concentration in calculating cerebral blood flow. We examined the effects of pulmonary disease and artificial ventilation on the air curve and the calculated cerebral blood flow. We studied the relation between arterial and end-tidal xenon activities in 19 subjects, of whom 15 had pulmonary dysfunction. The t 1/2 of the declining phases of the arterial and air curves were used to express their shapes. The mean +/- SD reference t 1/2 from 15 normal volunteers was 26.8 +/- 8.4 seconds. The mean +/- SD t 1/2 s of the air and arterial curves from the 15 patients with pulmonary dysfunction were 10.4 +/- 2.9 and 33.8 +/- 10.9 seconds. The degree of pulmonary dysfunction (expressed as the pulmonary shunt percentage) correlated with distortion of the air curve. Substituting the arterial for the air curve, mean calculated cerebral blood flow (as the initial slope index) increased from 40 to 61 for the 12 patients with chronic obstructive pulmonary disease. The degree of underestimation of cerebral blood flow using the air curve correlated with the pulmonary shunt percentage. Our work confirms the problems of estimating cerebral blood flow in subjects with pulmonary dysfunction.

  8. Diverse functions of pericytes in cerebral blood flow regulation and ischemia

    PubMed Central

    Fernández-Klett, Francisco; Priller, Josef

    2015-01-01

    Pericytes are mural cells with contractile properties. Here, we provide evidence that microvascular pericytes modulate cerebral blood flow in response to neuronal activity (‘functional hyperemia'). Besides their role in neurovascular coupling, pericytes are responsive to brain damage. Cerebral ischemia is associated with constrictions and death of capillary pericytes, followed by fibrotic reorganization of the ischemic tissue. The data suggest that precapillary arterioles and capillaries are major sites of hemodynamic regulation in the brain. PMID:25853910

  9. The Hemodynamic Effects of Blood Flow-Arterial Wall Interaction on Cerebral Aneurysms

    NASA Astrophysics Data System (ADS)

    Oshima, Marie

    2005-11-01

    Mechanical stresses such as wall shear induced by blood flow play an important role on cardiovascular diseases and cerebral disorders like arterioscleroses and cerebral aneurysm. In order to obtain a better understanding of mechanism of formation, growth, and rupture of cerebral aneurysm, this paper focuses on investigation of cerebral hemodynamics and its effects on aneurismal wall. The paper mainly consists of three parts. Since it is important to obtain the detailed information on the hemodynamic properties in the cerebral circulatory system, the first part discusses a large-scale hemodynamic simulation of the Cerebral Arterial Circle of Willis. The second part presents the simulation and in-vitro experiment of cerebral aneurysm with the consideration of blood flow-arterial wall interaction. Both simulations in the first and the second parts are conducted in a patient specific manner using medical images and also include modeling of boundary conditions to emulate realistic hemodynamic conditions. The present mathematical model, however, includes only macroscopic mechanical functions. Therefore, in the third part, the paper touches upon on future prospects in modeling of microscopic functions such as the effects of endothelial cells and multi physics functions such as physiological effects.

  10. Cerebral blood flow in experimental ischemia assessed by sup 19 F magnetic resonance spectroscopy in cats

    SciTech Connect

    Brunetti, A.; Nagashima, G.; Bizzi, A.; DesPres, D.J. )

    1990-10-01

    We evaluated a 19F magnetic resonance spectroscopic technique that detects Freon-23 washout as a means of measuring cerebral blood flow in halothane-anesthetized adult cats during and after transient cerebral ischemia produced by vascular occlusion. The experiments were performed to test the ability of this recently developed method to detect postischemic flow deficits. Results were consistent with postischemic hypoperfusion. The method also proved valuable for measuring small residual flow during vascular occlusion. Our experiments indicate that this method provides simple, rapid, and repeatable flow measurements that can augment magnetic resonance examinations of cerebral metabolic parameters in the study of ischemia.

  11. Regional brain blood flow and cerebral hemispheric oxygen consumption during acute hypoxaemia in the llama fetus

    PubMed Central

    Llanos, Aníbal J; Riquelme, Raquel A; Sanhueza, Emilia M; Herrera, Emilio; Cabello, Gertrudis; Giussani, Dino A; Parer, Julian T

    2002-01-01

    Unlike fetal animals of lowland species, the llama fetus does not increase its cerebral blood flow during an episode of acute hypoxaemia. This study tested the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral O2 extraction rather than decreasing cerebral oxygen utilisation during acute hypoxaemia. Six llama fetuses were surgically instrumented under general anaesthesia at 217 days of gestation (term ca 350 days) with vascular and amniotic catheters in order to carry out cardiorespiratory studies. Following a control period of 1 h, the llama fetuses underwent 3 × 20 min episodes of progressive hypoxaemia, induced by maternal inhalational hypoxia. During basal conditions and during each of the 20 min of hypoxaemia, fetal cerebral blood flow was measured with radioactive microspheres, cerebral oxygen extraction was calculated, and fetal cerebral hemispheric O2 consumption was determined by the modified Fick principle. During hypoxaemia, fetal arterial O2 tension and fetal pH decreased progressively from 24 ± 1 to 20 ± 1 Torr and from 7.36 ± 0.01 to 7.33 ± 0.01, respectively, during the first 20 min episode, to 16 ± 1 Torr and 7.25 ± 0.05 during the second 20 min episode and to 14 ± 1 Torr and 7.21 ± 0.04 during the final 20 min episode. Fetal arterial partial pressure of CO2 (Pa,CO2, 42 ± 2 Torr) remained unaltered from baseline throughout the experiment. Fetal cerebral hemispheric blood flow and cerebral hemispheric oxygen extraction were unaltered from baseline during progressive hypoxaemia. In contrast, a progressive fall in fetal cerebral hemispheric oxygen consumption occurred during the hypoxaemic challenge. In conclusion, these data do not support the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral hemispheric O2 extraction. Rather, the data show that in the llama fetus, a reduction in cerebral hemispheric metabolism occurs during acute

  12. Relationship of 133Xe cerebral blood flow to middle cerebral arterial flow velocity in men at rest

    NASA Technical Reports Server (NTRS)

    Clark, J. M.; Skolnick, B. E.; Gelfand, R.; Farber, R. E.; Stierheim, M.; Stevens, W. C.; Beck, G. Jr; Lambertsen, C. J.

    1996-01-01

    Cerebral blood flow (CBF) was measured by 133Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial PCO2 in eight normal men. Average arterial PCO2, which was varied by giving 4% and 6% CO2 in O2 and by controlled hyperventilation on O2, ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF15 were 27.2 and 65.0 ml 100 g min-1, respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial PCO2 was described analytically by a parabola with the equation: CBF = 22.8 - 0.17 x velocity + 0.006 x velocity2 The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial PCO2 during O2 breathing at rest. With respect to baseline values measured while breathing 100% O2 spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial PCO2 and larger than CBF changes at the lower arterial PCO2. These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

  13. Cerebral blood flow determination within the first 8 hours of cerebral infarction using stable xenon-enhanced computed tomography

    SciTech Connect

    Hughes, R.L.; Yonas, H.; Gur, D.; Latchaw, R.

    1989-06-01

    Cerebral blood flow mapping with stable xenon-enhanced computed tomography (Xe/CT) was performed in conjunction with conventional computed tomography (CT) within the first 8 hours after the onset of symptoms in seven patients with cerebral infarction. Six patients had hemispheric infarctions, and one had a progressive brainstem infarction. Three patients with very low (less than 10 ml/100 g/min) blood flow in an anatomic area appropriate for the neurologic deficit had no clinical improvement by the time of discharge from the hospital; follow-up CT scans of these three patients confirmed infarction in the area of very low blood flow. Three patients with moderate blood flow reductions (15-45 ml/100 g/min) in the appropriate anatomic area had significant clinical improvement from their initial deficits and had normal follow-up CT scans. One patient studied 8 hours after stroke had increased blood flow (hyperemia) in the appropriate anatomic area and made no clinical recovery.

  14. Assessing Regional Cerebral Blood Flow in Depression Using 320-Slice Computed Tomography

    PubMed Central

    Tang, Songlin; Liu, Xingde; O'Neil, Adrienne; Turner, Alyna; Chai, Fangxian; Chen, Fanying; Berk, Michael

    2014-01-01

    While there is evidence that the development and course of major depressive disorder (MDD) symptomatology is associated with vascular disease, and that there are changes in energy utilization in the disorder, the extent to which cerebral blood flow is changed in this condition is not clear. This study utilized a novel imaging technique previously used in coronary and stroke patients, 320-slice Computed-Tomography (CT), to assess regional cerebral blood flow (rCBF) in those with MDD and examine the pattern of regional cerebral perfusion. Thirty nine participants with depressive symptoms (Hamilton Depression Rating Scale 24 (HAMD24) score >20, and Self-Rating Depression Scale (SDS) score >53) and 41 healthy volunteers were studied. For all subjects, 3 ml of venous blood was collected to assess hematological parameters. Trancranial Doppler (TCD) ultrasound was utilized to measure parameters of cerebral artery rCBFV and analyse the Pulsatility Index (PI). 16 subjects (8 =  MDD; 8 =  healthy) also had rCBF measured in different cerebral artery regions using 320-slice CT. Differences among groups were analyzed using ANOVA and Pearson's tests were employed in our statistical analyses. Compared with the control group, whole blood viscosity (including high\\middle\\low shear rate)and hematocrit (HCT) were significantly increased in the MDD group. PI values in different cerebral artery regions and parameters of rCBFV in the cerebral arteries were decreased in depressive participants, and there was a positive relationship between rCBFV and the corresponding vascular rCBF in both gray and white matter. rCBF of the left gray matter was lower than that of the right in MDD. Major depression is characterized by a wide range of CBF impairments and prominent changes in gray matter blood flow. 320-slice CT appears to be a valid and promising tool for measuring rCBF, and could thus be employed in psychiatric settings for biomarker and treatment response purposes. PMID:25251476

  15. Persistent endothelial abnormalities and blood-brain barrier leak in primary and secondary progressive multiple sclerosis.

    PubMed

    Leech, S; Kirk, J; Plumb, J; McQuaid, S

    2007-02-01

    Epithelial and endothelial tight junctions are pathologically altered in infectious, inflammatory, neoplastic and other diseases. Previously, we described such abnormalities, associated with serum protein leak, in tight junctions of the blood-brain barrier endothelium, in lesional and normal-appearing white matter (NAWM) in secondary progressive (SP) and acute multiple sclerosis (MS). This work is extended here to lesions and NAWM in primary progressive multiple sclerosis (PPMS) and to cortical grey matter in PPMS and SPMS. Immunocytochemistry and semiquantitative confocal microscopy for the tight junction protein zonula occludens 1 (ZO-1) was performed on snap-frozen sections from PPMS (n = 6) and controls (n = 5). Data on 2103 blood vessels were acquired from active lesions (n = 10), inactive lesions (n = 15), NAWM (n = 42) and controls (n = 20). Data on 1218 vessels were acquired from normal-appearing grey matter (PPMS, 5; SPMS, 6; controls, 5). In PPMS abnormal ZO-1 expression in active white matter lesions and NAWM, was found in 42% and 13% of blood vessels, respectively, comparable to previous data from acute and SPMS. In chronic white matter plaques, however, abnormalities were considerably more frequent (37%) in PPMS than in SPMS. Abnormality was also more frequent in normal-appearing grey matter in SPMS (23%) than in PPMS (10%). In summary, abnormal tight junctions in both SPMS and PPMS are most frequent in active white matter lesions but persist in inactive lesions, particularly in PPMS. Abnormal tight junctions are also common in normal-appearing grey matter in SPMS. Persistent endothelial abnormality with leak (PEAL) is therefore widespread but variably expressed in MS and may contribute to disease progression. PMID:17239011

  16. PET evaluation of cerebral blood flow reactivity in symptomatic and asymptomatic carotid artery stenosis

    SciTech Connect

    Dey, H.M.; Brass, L.; Rich, D.

    1994-05-01

    The purpose of this study was to use acetazolamide (AZ) enhanced O-15 water PET to evaluate cerebral perfusion reserve in symptomatic and asymptomatic carotid artery stenosis. We hypothesized that impaired vasoreactivity would be associated with symptomatic disease and a higher likelihood of future ischemic events. Twenty-two patients with significant (>75%) carotid artery occlusion underwent cerebral blood flow imaging at baseline and following AZ infusion. Paired O-15 data sets were coregistered and globally normalized. Regions of interest were drawn on baseline blood flow images and superimposed upon (AZ - baseline) difference images to derive a % change in regional blood flow after AZ administration. The results showed a significant difference in cerebral perfusion reserve between symptomatic (n=19) and asymptomatic (n=3) carotid artery disease.

  17. Regional cerebral blood flow utilizing the gamma camera and xenon inhalation: reproducibility and clinical applications

    SciTech Connect

    Fox, R.A.; Knuckey, N.W.; Fleay, R.F.; Stokes, B.A.; Van der Schaaf, A.; Surveyor, I.

    1985-11-01

    A modified collimator and standard gamma camera have been used to measure regional cerebral blood flow following inhalation of radioactive xenon. The collimator and a simplified analysis technique enables excellent statistical accuracy to be achieved with acceptable precision in the measurement of grey matter blood flow. The validity of the analysis was supported by computer modelling and patient measurements. Sixty-one patients with subarachnoid hemorrhage, cerebrovascular disease or dementia were retested to determine the reproducibility of our method. The measured coefficient of variation was 6.5%. Of forty-six patients who had a proven subarachnoid hemorrhage, 15 subsequently developed cerebral ischaemia. These showed a CBF of 42 +/- 6 ml X minute-1 X 100 g brain-1 compared with 49 +/- 11 ml X minute-1 X 100 g brain-1 for the remainder. There is evidence that decreasing blood flow and low initial flow correlate with the subsequent onset of cerebral ischemia.

  18. Regional cerebral blood flow during hypoxia-ischemia in immature rats

    SciTech Connect

    Vannucci, R.C.; Lyons, D.T.; Vasta, F.

    1988-02-01

    Immature rats subjected to a combination of unilateral common carotid artery ligation and hypoxia sustain brain damage confined largely to the ipsilateral cerebral hemisphere. To ascertain the extent and distribution of ischemic alterations in the brains of these small animals, we modified the Sakurada technique to measure regional cerebral blood flow using carbon-14 autoradiography. Seven-day-old rats underwent right common carotid artery ligation following which they were rendered hypoxic with 8% O2 at 37 degrees C. Before and during hypoxia, the rat pups received an injection of iodo(/sup 14/C)antipyrine for determination of regional cerebral blood flow. Blood flows to individual structures of the ipsilateral cerebral hemisphere were not influenced by arterial occlusion alone; flows to the contralateral hemisphere and to the brainstem and cerebellum actually increased by 25-50%. Hypoxia-ischemia was associated with decreases in regional cerebral blood flow of the ipsilateral hemisphere such that by 2 hours, flows to subcortical white matter, neocortex, striatum, and thalamus were 15, 17, 34, and 41% of control, respectively. The hierarchy of the blood flow reductions correlated closely with the distribution and extent of ischemic neuronal necrosis. However, unlike the pathologic pattern of this model, the degree of ischemia appeared homogeneous within each brain region. Blood flows to contralateral cerebral hemispheric structures were relatively unchanged from prehypoxic values, whereas flows to the brainstem and cerebellum nearly doubled and tripled, respectively. Thus, ischemia is the predominant factor that determines the topography of tissue injury to major regions of immature rat brain, whereas metabolic factors may influence the heterogeneous pattern of damage seen within individual structures.

  19. Regional cerebral blood flow in dialysis encephalopathy and primary degenerative dementia

    SciTech Connect

    Mathew, R.J.; Rabin, P.; Stone, W.J.; Wilson, W.H.

    1985-07-01

    Regional cerebral blood flow (CBF) was measured in patients with dialysis encephalopathy, primary degenerative dementia, dialysis patients with no central nervous system (CNS) complications, and normal controls. Both groups of dialysis patients (with and without CNS complications) demonstrated higher CBF values, and the dementia patients, lower CBF values than the controls. The dialysis patients had lower hematocrit, which correlated inversely with the cerebral blood flow. No such correlations were present in normals and patients with primary degenerative dementia. The dialysis patients and controls obtained similar CBF when the flow values were adjusted for the differences in hematocrit.

  20. Evaluation of regional cerebral blood flow in patient with atypical senile dementia with asymmetrical calcification.

    PubMed

    Shoyama, Masaru; Ukai, Satoshi; Shinosaki, Kazuhiro

    2015-12-01

    We report an 83-year-old woman with atypical senile dementia with Fahr-type calcification. Brain computed tomography demonstrated asymmetrical calcification predominant in the basal ganglia on the right side and pronounced diffuse cortical atrophy in the frontotemporal areas. The patient was clinically diagnosed with diffuse neurofibrillary tangles with calcification. Brain single photon emission computed tomography findings revealed that cerebral blood flow was reduced on the right side, as compared with the left side, in widespread areas. Hemispheric asymmetry in both calcification and cerebral blood flow suggests a relationship between calcification and vascular changes. PMID:25737312

  1. Cerebral blood flow - Comparison of ground-based and spaceflight data and correlation with space adaptation syndrome

    NASA Technical Reports Server (NTRS)

    Bagian, James P.; Hackett, Peter

    1991-01-01

    The relationship between the cerebral blood flow velocity and the space adaptation syndrome (SAS), which includes symptoms of motion sickness, stuffy head, and/or headaches, was investigated by measuring (using a transcranial Doppler device) differences between the preflight and the inflight cerebral blood flow velocity in crew members who were motion sick and in those who were not sick during a flight aboard KC-135. It was found that the cerebral artery bloodflow inflight did not differ significantly from that recorded preflight, nor did the severity of SAS symptoms correlate directly with the cerebral blood flow.

  2. Effect of natriuretic peptides on cerebral artery blood flow in healthy volunteers.

    PubMed

    Guo, Song; Goetze, Jens P; Jeppesen, Jørgen L; Burnett, John C; Olesen, Jes; Jansen-Olesen, Inger; Ashina, Messoud

    2015-12-01

    The natriuretic peptides (NPs), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP), have vasoactive functions that concern humans and most animals, but their specific effects on cerebral circulation are poorly understood. We therefore examined the responsiveness of cerebral arteries to different doses of the natriuretic peptides in animals and humans. We conducted a dose-response experiment in guinea pigs (in vitro) and a double-blind, three-way cross-over study in healthy volunteers (in vivo). In the animal experiment, we administered cumulative doses of NPs to pre-contracted segments of cerebral arteries. In the main study, six healthy volunteers were randomly allocated to receive two intravenous doses of ANP, BNP or CNP, respectively, over 20 min on three separate study days. We recorded blood flow velocity in the middle cerebral artery (VMCA) by transcranial Doppler. In addition, we measured temporal and radial artery diameters, headache response and plasma concentrations of the NPs. In guinea pigs, ANP and BNP but not CNP showed significant dose-dependent relaxation of cerebral arteries. In healthy humans, NP infusion had no effect on mean VMCA, and we found no difference in hemodynamic responses between the NPs. Furthermore, natriuretic peptides did not affect temporal and radial artery diameters or induce headache. In conclusion, natriuretic peptides in physiological and pharmacological doses do not affect blood flow velocity in the middle cerebral artery or dilate extracerebral arteries in healthy volunteers. PMID:26417835

  3. Cerebral cortical neurons with activity linked to central neurogenic spontaneous and evoked elevations in cerebral blood flow

    NASA Technical Reports Server (NTRS)

    Golanov, E. V.; Reis, D. J.

    1996-01-01

    We recorded neurons in rat cerebral cortex with activity relating to the neurogenic elevations in regional cerebral blood flow (rCBF) coupled to stereotyped bursts of EEG activity, burst-cerebrovascular wave complexes, appearing spontaneously or evoked by electrical stimulation of rostral ventrolateral medulla (RVL) or fastigial nucleus (FN). Of 333 spontaneously active neurons only 15 (5%), in layers 5-6, consistently (P < 0.05, chi-square) increased their activity during the earliest potential of the complex, approximately 1.3 s before the rise of rCBF, and during the minutes-long elevation of rCBF elicited by 10 s of stimulation of RVL or FN. The results indicate the presence of a small population of neurons in deep cortical laminae whose activity correlates with neurogenic elevations of rCBF. These neurons may function to transduce afferent neuronal signals into vasodilation.

  4. Children with New Onset Epilepsy Exhibit Diffusion Abnormalities in Cerebral White Matter in the Absence of Volumetric Differences

    PubMed Central

    Hutchinson, Elizabeth; Pulsipher, Dalin; Dabbs, Kevin; Myers y Gutierrez, Adan; Sheth, Raj; Jones, Jana; Seidenberg, Michael; Meyerand, Elizabeth; Hermann, Bruce

    2010-01-01

    SUMMARY The purpose of this investigation was to examine the diffusion properties of cerebral white matter in children with recent onset epilepsy (n=19) compared to healthy controls (n=11). Subjects underwent DTI with quantification of mean diffusion (MD), fractional anisotropy (FA), axial diffusivity (Dax) and radial diffusivity (Drad) for regions of interest including anterior and posterior corpus callosum, fornix, cingulum, and internal and external capsules. Quantitative volumetrics were also performed for the corpus callosum and its subregions (anterior, midbody and posterior) and total lobar white and gray matter for the frontal, parietal, temporal and occipital lobes. The results demonstrated no group differences in total lobar gray or white matter volumes or volume of the corpus callosum and its subregions, but did show reduced FA and increased Drad in the posterior corpus callosum and cingulum. These results provide the earliest indication of microstructural abnormality in cerebral white matter among children with idiopathic epilepsies. This abnormality occurs in the context of normal volumetrics and suggests disruption in myelination processes. PMID:20044239

  5. The effect of hyperoxia on cerebral blood flow: a study in healthy volunteers using magnetic resonance phase-contrast angiography.

    PubMed

    Watson, N A; Beards, S C; Altaf, N; Kassner, A; Jackson, A

    2000-03-01

    A small decrease in cerebral blood flow (approximately 10%) in response to 100% oxygen (O2) administration is well recognized. This observation was based on human volunteer studies, which employed a nitrous oxide washout method for the measurement of cerebral blood flow. Because this method is now appreciated to be subject to potential errors we have examined the cerebral blood flow response to 100% oxygen using a magnetic resonance imaging technique to quantify changes in carotid and basilar artery flow. The study, was performed in 12 normal male subjects aged 23-42 years. We report decreases in cerebral blood flow ranging from 9 to 31% with a mean value of over 20%. The decrease in cerebral blood flow was greater in seven young subjects (aged 23-26 years) with decreases in cerebral blood flow of 19.3-31.4% (mean 26.8%). In five older subjects (aged 32-42 years), decreases in CBF were smaller (mean 16. 2%). The administration of 100% O2 was accompanied by a small decrease in end-tidal CO2 (3.7-7.1%), insufficient to explain the changes in cerebral blood flow. We conclude that the decrease in cerebral blood flow in response to O2 administration is greater than previously described and appears to be greater in young adults. PMID:10758463

  6. Outcome of Fetuses with Cerebral Ventriculomegaly and Septum Pellucidum Leaflet Abnormalities

    PubMed Central

    Li, Y; Sansgiri, R; Estroff, JA; Mehta, TS; Poussaint, TY; Robertson, RL; Robson, CD; Feldman, HA; Barnewolt, C; Levine, D

    2013-01-01

    Objective To assess outcomes of prenatal diagnosis of septal leaflet abnormality in fetuses referred for ventriculomegaly (VM). Methods In a prospective IRB-approved study with written informed consent, between 7/1/2003 to 5/15/2009, 425 pregnant women with 433 fetuses referred for VM were imaged with US and MRI. Four to six radiologists independently reviewed sonographic and MR images and recorded lateral ventricular diameters at the atrium and frontal horns, ventricular configuration, and the presence of VM and other CNS abnormalities. Final US, MR, and overall prenatal diagnoses were decided by consensus. Fetuses coded for septal leaflet abnormality were identified, and birth outcome, autopsy, postnatal imaging, and postnatal follow-up were obtained. Log-transformed ANCOVA, controlling for GA, was used to compare ventricular dimensions between fetuses with septal leaflet abnormalities and fetuses with isolated VM. Inter-rater agreement of septal leaflet abnormality was assessed with kappa statistics. Results 23 fetuses had septal leaflet abnormalities and 229 had isolated VM. Atrial and frontal horn diameters, adjusted for GA, were 77% and 98% larger, respectively, in fetuses with septal leaflet abnormalities than in fetuses with isolated VM (p<0.0001). Pre-conference consensus among US readers was moderate (kappa = 0.54) and among MR readers was good (kappa = 0.69). Additional MR CNS findings were seen in 12/23 (52%) fetuses. Eleven pregnancies with septal leaflet abnormalities underwent termination and 12 progressed to live birth with 3 neonatal demise. Neurodevelopmental follow-up was abnormal in all surviving children. Conclusion Even when septal leaflet abnormality is an isolated finding, developmental delay can occur postnatally. PMID:21178039

  7. Effects of GABA(A) receptor blockade on regional cerebral blood flow and blood-brain barrier disruption in focal cerebral ischemia.

    PubMed

    Chi, Oak Z; Hunter, Christine; Liu, Xia; Chi, Youngchan; Weiss, Harvey R

    2011-02-15

    In cerebral ischemia, transmission by the inhibitory neurotransmitter, γ-aminobutyric acid (GABA) is altered. This study was performed to determine whether blockade of GABA(A) receptor would affect regional cerebral blood flow (rCBF) and blood-brain barrier (BBB) permeability in a focal ischemic area of the brain. Rats were anesthetized with isoflurane and mechanically ventilated. Fifteen minutes after a permanent middle cerebral artery (MCA) occlusion, one half of the rats were infused with bicuculline 1mg/kg/min iv for 2 min followed by 0.1mg/kg/min iv to the end of the experiment. The other half were infused with normal saline. At one hour after MCA occlusion, rCBF was determined using ¹⁴C-iodoantipyrine and BBB permeability was determined by measuring the transfer coefficient (Ki) of ¹⁴C-α-aminoisobutyric acid. With MCA occlusion, rCBF was decreased in the ischemic cortex (IC) (-70%) in the control rats. In the bicuculline treated rats, the rCBF of the IC was lower (-48%) than the contralateral cortex but higher than the rCBF of the IC of the control rats (+55%). MCA occlusion increased Ki in the IC of the control rats (+72%) and bicuculline administration increased Ki further (+53%) in the IC. Blockade of GABA(A) receptors did not significantly affect rCBF or BBB permeability in the non-ischemic brain regions under isoflurane anesthesia. Our data demonstrated that blockade of GABA(A) receptors increased rCBF and enhanced the BBB disruption in focal cerebral ischemia. Our data suggest that GABA(A) receptors are involved, at least in part, in modulating rCBF and BBB disruption in focal cerebral ischemia. PMID:21094956

  8. Cerebral Blood Flow Estimation Using Classification Techniques On A Sequence Of Low Resolution Tomographic Evolutive Images

    NASA Astrophysics Data System (ADS)

    Chan, Marie; Aguilar-Martin, Joseph; Boulanouar, Kader; Celsis, Pierre; Marc-Vergnes, Jean P.

    1989-05-01

    In order to improve the performance of the instrumental variable method (IVM) in calculating regional cerebral blood flow (rCBF) using Single Photon Emission Computed Tomography (SPELT), and inert diffusible tracer such as 133Xe, we use Learning Algorithms for Multivariate Data Analysis (LAMDA) to classify the voxels of the images of local concentrations in the brain. The LAMDA method correctly distinguished between extra and intra-cerebral voxels. However the topography of the intra-cerebral classes did not match the Regions Of Interest (ROI) defined on an anatomical basis. Provided that all the intra-cerebral classes contaminated by bone and air passage artefact were rejected, the results given by the NM are in good agreement with those derived by the bolus distribution principle. We thus conclude that LAMDA methods can improve the reliability of images of CBF estimates.

  9. Autologous Cord Blood Therapy for Infantile Cerebral Palsy: From Bench to Bedside

    PubMed Central

    Jensen, A.

    2014-01-01

    About 17 million people worldwide live with cerebral palsy, the most common disability in childhood, with hypoxic-ischemic encephalopathy, preterm birth, and low birth weight being the most important risk factors. This review will focus on recent developments in cell therapy for infantile cerebral palsy by transplantation of autologous umbilical cord blood. There are only 4 publications available at present; however, the observations made along with experimental data in vivo and in vitro may be of utmost importance clinically, so that a review at an early developmental stage of this new therapeutic concept seems justified. Particularly, since the first published double-blind randomized placebo-controlled trial in a paradigm using allogeneic cord blood and erythropoietin to treat cerebral palsy under immunosuppression showed beneficial therapeutic effects in infantile cerebral palsy, long-held doubts about the efficacy of this new cell therapy are dispelled and a revision of therapeutic views upon an ailment, for which there is no cure at present, is warranted. Hence, this review will summarize the available information on autologous cord blood therapy for cerebral palsy and that on the relevant experimental work as far as potential mechanisms and modes of action are concerned. PMID:24695413

  10. Cerebral aneurysms treated with flow-diverting stents: Computational models using intravascular blood flow measurements

    PubMed Central

    Levitt, Michael R; McGah, Patrick M; Aliseda, Alberto; Mourad, Pierre D; Nerva, John D; Vaidya, Sandeep S; Morton, Ryan P; Ghodke, Basavaraj V; Kim, Louis J

    2013-01-01

    Background and Purpose Computational fluid dynamics modeling is useful in the study of the hemodynamic environment of cerebral aneurysms, but patient-specific measurements of boundary conditions, such as blood flow velocity and pressure, have not been previously applied to the study of flow-diverting stents. We integrated patient-specific intravascular blood flow velocity and pressure measurements into computational models of aneurysms before and after treatment with flow-diverting stents to determine stent effects on aneurysm hemodynamics. Methods Blood flow velocity and pressure were measured in peri-aneurysmal locations using an intravascular dual-sensor pressure and Doppler velocity guidewire before and after flow-diverting stent treatment of four unruptured cerebral aneurysms. These measurements defined inflow and outflow boundary conditions for computational models. Intra-aneurysmal flow rates, wall shear stress and wall shear stress gradient were calculated. Results Measurements of inflow velocity and outflow pressure were successful in all four patients. Computational models incorporating these measurements demonstrated significant reductions in intra-aneurysmal wall shear stress and wall shear stress gradient, and a trend in reduced intra-aneurysmal blood flow. Conclusions Integration of intravascular dual-sensor guidewire measurements of blood flow velocity and blood pressure provided patient-specific computational models of cerebral aneurysms. Aneurysm treatment with flow-diverting stents reduces blood flow and hemodynamic shear stress in the aneurysm dome. PMID:23868162

  11. Noninvasive cerebral blood oxygenation monitoring: clinical test of multiwavelength optoacoustic system

    NASA Astrophysics Data System (ADS)

    Petrov, Y. Y.; Prough, D. S.; Petrova, I.; Patrikeev, I. A.; Cicenaite, I.; Esenaliev, R. O.

    2007-02-01

    Continuous monitoring of cerebral blood oxygenation is critically important for treatment of patients with life-threatening conditions like severe brain injury or during cardiac surgery. We designed and built a novel multiwavelength optoacoustic system for noninvasive, continuous, and accurate monitoring of cerebral blood oxygenation. We use an Optical Parametric Oscillator as a light source. We successfully tested the system in vitro as well as in vivo in large animals (sheep) through thick tissues overlying blood vessels which drain venous blood out of the brain (e.g., superior sagittal sinus or jugular vein). Here we present the results of clinical tests of the system for continuous noninvasive cerebral blood oxygenation monitoring in the internal jugular vein of healthy volunteers. We applied our custom-built optoacoustic probe (which incorporated a wide-band acoustic transducer and an optical fiber) to the neck area overlying the internal jugular vein. We performed measurements with volunteers at 18 wavelengths in the near-infrared spectral range. Despite a thick layer of overlying connective tissue and low energy used in the experiments, we recorded signals with high signal-to-noise ratios for all volunteers. We found that the temporal (independent of signal amplitude) parameters of recorded profiles for different levels of blood oxygenation correlated well with the spectrum of effective attenuation coefficients of blood.

  12. Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males.

    PubMed

    Hirasawa, Ai; Kaneko, Takahito; Tanaka, Naoki; Funane, Tsukasa; Kiguchi, Masashi; Sørensen, Henrik; Secher, Niels H; Ogoh, Shigehiko

    2016-04-01

    We estimated cerebral oxygenation during handgrip exercise and a cognitive task using an algorithm that eliminates the influence of skin blood flow (SkBF) on the near-infrared spectroscopy (NIRS) signal. The algorithm involves a subtraction method to develop a correction factor for each subject. For twelve male volunteers (age 21 ± 1 yrs) +80 mmHg pressure was applied over the left temporal artery for 30 s by a custom-made headband cuff to calculate an individual correction factor. From the NIRS-determined ipsilateral cerebral oxyhemoglobin concentration (O2Hb) at two source-detector distances (15 and 30 mm) with the algorithm using the individual correction factor, we expressed cerebral oxygenation without influence from scalp and scull blood flow. Validity of the estimated cerebral oxygenation was verified during cerebral neural activation (handgrip exercise and cognitive task). With the use of both source-detector distances, handgrip exercise and a cognitive task increased O2Hb (P < 0.01) but O2Hb was reduced when SkBF became eliminated by pressure on the temporal artery for 5 s. However, when the estimation of cerebral oxygenation was based on the algorithm developed when pressure was applied to the temporal artery, estimated O2Hb was not affected by elimination of SkBF during handgrip exercise (P = 0.666) or the cognitive task (P = 0.105). These findings suggest that the algorithm with the individual correction factor allows for evaluation of changes in an accurate cerebral oxygenation without influence of extracranial blood flow by NIRS applied to the forehead. PMID:26018458

  13. Optical measurement of mouse strain differences in cerebral blood flow using indocyanine green

    PubMed Central

    Kang, Hye-Min; Sohn, Inkyung; Kim, Seunggyu; Kim, Daehwan; Jung, Junyang; Jeong, Joo-Won; Park, Chan

    2015-01-01

    C57BL/6 mice have more cerebral arterial branches and collaterals than BALB/c mice. We measured and compared blood flow dynamics of the middle cerebral artery (MCA) in these two strains, using noninvasive optical imaging with indocyanine green (ICG). Relative maximum fluorescence intensity (Imax) and the time needed for ICG to reach Imax in the MCA of C57BL/c were lower than that in BALB/c mice. Moreover, the mean transit time was significantly lower in C57BL/6 than in BALB/c mice. These data suggest that the higher number of arterial branches and collaterals in C57BL/6 mice yields a lower blood flow per cerebral artery. PMID:25833343

  14. I-123 hydroxyiodobenzyl propanediamine (HIPDM) cerebral blood flow imaging demonstrating transtentorial diaschisis

    SciTech Connect

    Shih, W.J.; Dekosky, S.T.; Coupal, J.J.; Simmons, G.; Pulmano, C.; Kung, H.F.; Ryo, U.Y.; Clark, D.B. )

    1990-09-01

    To assess the clinical significance of transtentorial diaschisis (TTD) as demonstrated by I-123 HIPDM brain imaging, SPECT and/or planar images of 35 patients with stroke, 26 patients with Alzheimer's disease (AD), 2 patients with Creutzfeldt-Jakob disease (CJD), and 1 patient with a schizoaffective disorder were analyzed. TTD was observed in 21 of the 35 patients with strokes. In 13 stroke patients, TTD was associated with large infarcts in the middle cerebral artery (MCA) territory; in the remaining 8 stroke patients, TTD was associated with internal capsule and/or basal ganglia infarcts. TTD was not associated with small occipital or parietal infarcts. Despite cortical perfusion decrements, TTD was not seen in the AD patients, the CJD patients, or the patient with schizoaffective disorder. It is concluded that (1) TTD frequently occurs following cerebral infarct of the MCA territory (60% of the patients in this sample); (2) absence of TTD in the presence of a large cerebral perfusion abnormality may represent neuronal dysfunction of the cerebral cortex; and (3) the presence of TTD without a significant cortical perfusion abnormality may indicate basal ganglia and/or internal capsule infarct.

  15. Radiohalogenated thienylethylamine derivatives for evaluating local cerebral blood flow

    SciTech Connect

    Goodman, M.M.; Knapp, F.F. Jr.

    1990-02-13

    This patent describes radiopharmaceuticals useful in brain imaging. They comprise radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation or regional blood flow by radioimaging of the brain.

  16. Radiohalogenated thienylethylamine derivatives for evaluating local cerebral blood flow

    DOEpatents

    Goodman, Mark M.; Knapp, Jr., Furn F.

    1990-01-01

    Radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation or regional blood flow by radioimaging of the brain.

  17. A venous outflow method for measurement of rapid changes of the cerebral blood flow and oxygen consumption in the rat.

    PubMed

    Nilsson, B; Siesjö, B K

    1983-01-01

    A technique for continuous measurement of cerebral venous outflow in the rat is described. The method involves cannulation of one retroglenoid vein close to its exit from the skull, and diversion of cerebral venous blood through a closed extracorporal circuit with a drop recording device, the blood being returned to the central venous circulation via a catheter in the external jugular vein. Occlusion of the contralateral retroglenoid vein increases measured flow and minimizes extracerebral contamination of the diverted cerebral venous blood. The venous outflow system is not further isolated from cerebral or potential extracerebral collaterals. Thus, the mass of tissue drained cannot be exactly defined anatomically. However, the experiments involving changes of PP, arterial CO2 tension, and induction of epileptic seizure activity, and simultaneous indirect measurements with radioactive tracer technique, indicate that significant extracerebral contamination does not occur and that in short term measurements the venous outflow represents cerebral blood flow (CBF) in a constant mass of (dorsal and central, mainly forebrain) cerebral tissue. Measurement of arterial blood pressure and pressure in the cisterna magna allows calculation of cerebral perfusion pressure (PP). By simultaneous measurement of arterial and cerebral venous oxygen content changes in cerebral oxygen consumption (CMRO2) can be calculated. The method has been applied to document several situations of transient CBF and CMRO2 changes. PMID:6658967

  18. Data on copper level in the blood of patients with normal and abnormal angiography.

    PubMed

    Amiri, Leila; Movahed, Ali; Iranpour, Dariush; Ostovar, Afshin; Raeisi, Alireza; Keshtkar, Mozhgan; Hajian, Najmeh; Dobaradaran, Sina

    2016-12-01

    In this data article, we measured the levels of copper in the blood of patients undergoing coronary angiography. The samples were taken from patients with cardiovascular disease in Bushehr׳s university hospital, Iran. Patients were divided in two groups: normal angiography and abnormal angiography. After the chemical digestion of samples, the concentration levels of Cu in both groups were determined by using inductively coupled plasma optical spectrometry (ICP-OES). PMID:27622204

  19. Increased Cerebral Blood Flow Associated with Better Response Inhibition in Bipolar Disorder

    PubMed Central

    Dev, Sheena I.; McKenna, Benjamin S.; Sutherland, Ashley N.; Shin, David D.; Liu, Thomas T.; Wierenga, Christina E.; Eyler, Lisa T.

    2015-01-01

    Impairment on inhibitory tasks has been well documented in bipolar disorder (BD). Differences in cerebral blood flow (CBF) between BD patients and healthy comparison (HC) participants have also been reported. Few studies have examined the relationship between cognitive performance and regional CBF in this patient population. We hypothesized that group differences on an inhibitory task (the Delis-Kaplan Executive Function Scale’s Color-Word Inhibition task) would be associated with differential CBF in bilateral anterior cingulate cortex (ACC), inferior parietal lobule (IPL) and dorsolateral prefrontal cortex (DLPFC) regions. Whole brain resting CBF was measured using Multiphase Pseudocontinuous Arterial Spin Labeling MR imaging for 28 euthymic BD and 36 HC participants. Total gray matter (GM) CBF was measured, and regional CBF values were extracted for each region of interest (ROI) using Freesurfer-based individual parcellations. Group, CBF, and group-by-CBF interaction were examined as predictors of inhibition performance. Groups did not differ in age, gender or education. BD patients performed significantly worse on Color-Word inhibition. There were no significant group differences in CBF in either total GM or in any ROI. There was a group by CBF interaction in the bilateral ACC, right IPL and right DLPFC such that better inhibitory performance was generally associated with higher resting state CBF in BD subjects, but not HC participants. Although CBF was not abnormal in this euthymic BD sample, results confirm previous reports of inter-episode inhibitory deficits and indicate that the perfusion-cognition relationship is different in BD compared to HC individuals. PMID:25771682

  20. Instability of the Middle Cerebral Artery Blood Flow in Response to CO2

    PubMed Central

    Regan, Rosemary E.; Duffin, James; Fisher, Joseph A.

    2013-01-01

    Background The middle cerebral artery supplies long end-artery branches to perfuse the deep white matter and shorter peripheral branches to perfuse cortical and subcortical tissues. A generalized vasodilatory stimulus such as carbon dioxide not only results in an increase in flow to these various tissue beds but also redistribution among them. We employed a fast step increase in carbon dioxide to detect the dynamics of the cerebral blood flow response. Methodology/Principal Findings The study was approved by the Research Ethics Board of the University Health Network at the University of Toronto. We used transcranial ultrasound to measure the time course of middle cerebral artery blood flow velocity in 28 healthy adults. Normoxic, isoxic step increases in arterial carbon dioxide tension of 10 mmHg from both hypocapnic and normocapnic baselines were produced using a new prospective targeting system that enabled a more rapid step change than has been previously achievable. In most of the 28 subjects the responses at both carbon dioxide ranges were characterised by more complex responses than a single exponential rise. Most responses were characterised by a fast initial response which then declined rapidly to a nadir, followed by a slower secondary response, with some showing oscillations before stabilising. Conclusions/Significance A rapid step increase in carbon dioxide tension is capable of inducing instability in the cerebral blood flow control system. These dynamic aspects of the cerebral blood flow responses to rapid changes in carbon dioxide must be taken into account when using transcranial blood flow velocity in a single artery segment to measure cerebrovascular reactivity. PMID:23936248

  1. Intraventricular hemorrhage in the preterm neonate: timing and cerebral blood flow changes

    SciTech Connect

    Ment, L.R.; Duncan, C.C.; Ehrenkranz, R.A.; Lange, R.C.; Taylor, K.J.; Kleinman, C.S.; Scott, D.T.; Sivo, J.; Gettner, P.

    1984-03-01

    Serial cranial ultrasound studies, 133xenon inhalation cerebral blood flow determinations, and risk factor analyses were performed in 31 preterm neonates. Contrast echocardiographic studies were additionally performed in 16 of these 31 infants. Sixty-one percent were found to have germinal matrix or intraventricular hemorrhage. Seventy-four percent of all hemorrhages were detected by the thirtieth postnatal hour. The patients were divided into three groups: early GMH/IVH by the sixth postnatal hour (eight infants) interval GMH/IVH from 6 hours through 5 days (10), and no GMH/IVH (12). Cerebral blood flow values at 6 postnatal hours were significantly lower for the early GMH/IVH group than for the no GMH/IVH group (P less than 0.01). Progression of GMH/IVH was observed only in those infants with early hemorrhage, and these infants had a significantly higher incidence of neonatal mortality. Ventriculomegaly as determined by ultrasound studies was noted equally in infants with and without GMH/IVH (50%) and was not found to correlate with low cerebral blood flow. The patients with early hemorrhage were distinguishable by their need for more vigorous resuscitation at the time of birth and significantly higher ventilator settings during the first 36 postnatal hours, during which time they also had higher values of PCO2. An equal incidence of patent ductus arteriosus was found across all of the groups. We propose that early GMH/IVH may be related to perinatal events and that the significant decrease in cerebral blood flow found in infants with early GMH/IVH is secondary to the presence of the hemorrhage itself. Progression of early GMH/IVH and new interval GMH/IVH may be related to later neonatal events known to alter cerebral blood flow.

  2. Abnormal neutrophil adhesion in sickle cell anaemia and crisis: relationship to blood rheology.

    PubMed

    Boghossian, S H; Nash, G; Dormandy, J; Bevan, D H

    1991-07-01

    Defects in neutrophil adhesion and migration may contribute to the susceptibility to infection seen in sickle cell anaemia (SCA). These dynamic defects may be influenced by abnormalities in blood rheology found in this disorder. A whole blood model was used to study neutrophil adhesion in SCA patients: neutrophil adhesion to protein coated glass was quantitated by measuring the rate of disappearance of neutrophils from heparinized whole blood circulating through a perfusion chamber. Twenty-three adult patients (Hb SS) were studied in asymptomatic steady state, of whom nine were also studied during pain crisis, both before and 4-7 d after conventional therapy. Red cell and granulocyte filterability and whole blood and plasma viscosity were also measured. The half-time for disappearance from the perfusion system (t1/2) of neutrophils from patients in the steady-state was 93.5 +/- 8.4 min, compared to 49.1 +/- 2.8 min in normal age-matched controls (P = 0.001). In crisis t1/2 was further prolonged to 170.0 +/- 16.1 min (P = 0.01 v. steady state). After therapy, t1/2 decreased to 57.0 +/- 4.5 min (P = 0.001 v. pre-therapy state and P = 0.009 v. steady state) and was comparable to Hb AA controls. These findings reveal a neutrophil adhesion defect in SCA which worsens in crisis but is corrected following supportive therapy. Red cell filterability (expressed as average resistance to flow and pore-clogging particles) and white cell filterability (expressed as pore-clogging particles) were also abnormal in SCA and were found to correlate with neutrophil adhesion. Plasma viscosity also correlated with adhesion t1/2. The defect appears to be related to abnormal blood flow properties in SCA but the rheological factors cannot fully explain either the steady-state defect or the marked changes in neutrophil adhesion during crisis. PMID:1873228

  3. Cerebral circulation, metabolism, and blood-brain barrier of rats in hypocapnic hypoxia

    SciTech Connect

    Beck, T.; Krieglstein, J.

    1987-03-01

    The effects of hypoxic hypoxia on physiological variables, cerebral circulation, cerebral metabolism, and blood-brain barrier were investigated in conscious, spontaneously breathing rats by exposing them to an atmosphere containing 7% O/sub 2/. Hypoxia affected a marked hypotension, hypocapnia and alkalosis. Cortical tissue high-energy phosphates and glucose content were not affected by hypoxia, glucose 6-phosphate lactate, and pyruvate levels were significantly increased. Blood-brain barrier permeability, regional brain glucose content and lumped constant were not changed by hypoxia. Local cerebral glucose utilization (LCGU) rose by 40-70% of control values in gray matter and by 80-90% in white matter. Under hypoxia, columns of increased and decreased LCGU and were detectable in cortical gray matter. Color-coded (/sup 14/C)2-deoxy-D-glucose autoradiograms of rat brain are shown. Local cerebral blood flow (LCBF) increased by 50-90% in gray matter and by up to 180% in white matter. Coupling between LCGU and LCBF in hypoxia remained unchanged. The data suggests a stimulation of glycolysis, increased glucose transport into the cell, and increased hexokinase activity. The physiological response of gray and white matter to hypoxia obviously differs. Uncoupling of the relation between LCGU and LCBF does not occur.

  4. Cerebral blood flow imaging using time-series analysis of indocyanine green molecular dynamics in mice

    NASA Astrophysics Data System (ADS)

    Ku, Taeyun; Lee, Jungsul; Choi, Chulhee

    2010-02-01

    Measurement of cerebral perfusion is important for study of various brain disorders such as stroke, epilepsy, and vascular dementia; however, efficient and convenient methods which can provide quantitative information about cerebral blood flow are not developed. Here we propose an optical imaging method using time-series analysis of dynamics of indocyanine green (ICG) fluorescence to generate cerebral blood flow maps. In scalp-removed mice, ICG was injected intravenously, and 740nm LED light was illuminated for fluorescence emission signals around 820nm acquired by cooled-CCD. Time-lapse 2-dimensional images were analyzed by custom-built software, and the maximal time point of fluorescent influx in each pixel was processed as a blood flow-related parameter. The generated map exactly reflected the shape of the brain without any interference of the skull, the dura mater, and other soft tissues. This method may be further applicable for study of other disease models in which the cerebral hemodynamics is changed either acutely or chronically.

  5. Cerebral blood flow response to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in children

    SciTech Connect

    Kern, F.H.; Ungerleider, R.M.; Quill, T.J.; Baldwin, B.; White, W.D.; Reves, J.G.; Greeley, W.J. )

    1991-04-01

    We examined the relationship of changes in partial pressure of carbon dioxide on cerebral blood flow responsiveness in 20 pediatric patients undergoing hypothermic cardiopulmonary bypass. Cerebral blood flow was measured during steady-state hypothermic cardiopulmonary bypass with the use of xenon 133 clearance methodology at two different arterial carbon dioxide tensions. During these measurements there was no significant change in mean arterial pressure, nasopharyngeal temperature, pump flow rate, or hematocrit value. Cerebral blood flow was found to be significantly greater at higher arterial carbon dioxide tensions (p less than 0.01), so that for every millimeter of mercury rise in arterial carbon dioxide tension there was a 1.2 ml.100 gm-1.min-1 increase in cerebral blood flow. Two factors, deep hypothermia (18 degrees to 22 degrees C) and reduced age (less than 1 year), diminished the effect carbon dioxide had on cerebral blood flow responsiveness but did not eliminate it. We conclude that cerebral blood flow remains responsive to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in infants and children; that is, increasing arterial carbon dioxide tension will independently increase cerebral blood flow.

  6. Treatment of blood flow abnormality using mucosal delivery of nitric oxide.

    PubMed

    Lee, Chi H

    2011-06-01

    This review focuses on clinical application of intravaginal formulations containing nitric oxide (NO). Poly(D,L-lactic acid-co-glycolic acid)-based microparticles or nanoparticles encapsulated with nitric oxide prodrugs, such as diethylenetriamine diazeniumdiolate and S-nitrosoglutathione, have been developed for the treatment of blood flow abnormality in various diseases including diabetes. Advanced nanotechnology allows for production of novel formulations with the capability of long-term protection, preserving the integrity of the NO donors, and delivering NO in a controlled and sustained release manner at the mucosal sites. The gene expressions of MAPK and PKC in the vaginal mucosa upon exposure to microparticles were evaluated for the mechanistic study involved with blood flow changes. The blood flow changes and protein expression of the vaginal mucosa upon exposure to intravaginal formulations containing NO donors supported that NO therapy would be suitable for the treatment of blood flow abnormality. This review subsequently would help to establish a scientific foundation for clinical trials of intravaginal NO delivery systems in humans. PMID:25788240

  7. Influence of cerebrovascular resistance on the dynamic relationship between blood pressure and cerebral blood flow in humans.

    PubMed

    Smirl, J D; Tzeng, Y C; Monteleone, B J; Ainslie, P N

    2014-06-15

    We examined the hypothesis that changes in the cerebrovascular resistance index (CVRi), independent of blood pressure (BP), will influence the dynamic relationship between BP and cerebral blood flow in humans. We altered CVRi with (via controlled hyperventilation) and without [via indomethacin (INDO, 1.2 mg/kg)] changes in PaCO2. Sixteen subjects (12 men, 27 ± 7 yr) were tested on two occasions (INDO and hypocapnia) separated by >48 h. Each test incorporated seated rest (5 min), followed by squat-stand maneuvers to increase BP variability and improve assessment of the pressure-flow dynamics using linear transfer function analysis (TFA). Beat-to-beat BP, middle cerebral artery velocity (MCAv), posterior cerebral artery velocity (PCAv), and end-tidal Pco2 were monitored. Dynamic pressure-flow relations were quantified using TFA between BP and MCAv/PCAv in the very low and low frequencies through the driven squat-stand maneuvers at 0.05 and 0.10 Hz. MCAv and PCAv reductions by INDO and hypocapnia were well matched, and CVRi was comparably elevated (P < 0.001). During the squat-stand maneuvers (0.05 and 0.10 Hz), the point estimates of absolute gain were universally reduced, and phase was increased under both conditions. In addition to an absence of regional differences, our findings indicate that alterations in CVRi independent of PaCO2 can alter cerebral pressure-flow dynamics. These findings are consistent with the concept of CVRi being a key factor that should be considered in the correct interpretation of cerebral pressure-flow dynamics as indexed using TFA metrics. PMID:24744385

  8. Abnormal sitting pressures of hemiplegic cerebral palsy children on a school chair

    PubMed Central

    Lee, In-Hee; Park, Sang-young

    2015-01-01

    [Purpose] The purpose of this study was to investigate the differences in symmetry of sitting posture between typical developmental (TD) children and hemi-cerebral palsy (CP) children. [Subjects and Methods] A school chair mounted on a force platform was used to assess the quiet-sitting pressure distribution of 10 TD and 10 CP children. [Results] The symmetry index of the TD children was significantly closer to zero than that of the CP children irrespective of the latter group’s hemiparetic side. [Conclusions] Sitting posture on school chairs of CP children was more asymmetrical than that of TD children. PMID:25729201

  9. Spatiotemporal changes in blood-brain barrier permeability, cerebral blood flow, T2 and diffusion following mild traumatic brain injury.

    PubMed

    Li, Wei; Watts, Lora; Long, Justin; Zhou, Wei; Shen, Qiang; Jiang, Zhao; Li, Yunxia; Duong, Timothy Q

    2016-09-01

    The blood-brain barrier (BBB) can be impaired following traumatic brain injury (TBI), however the spatiotemporal dynamics of BBB leakage remain incompletely understood. In this study, we evaluated the spatiotemporal evolution of BBB permeability using dynamic contrast-enhanced MRI and measured the volume transfer coefficient (K(trans)), a quantitative measure of contrast agent leakage across the blood and extravascular compartment. Measurements were made in a controlled cortical impact (CCI) model of mild TBI in rats from 1h to 7 days following TBI. The results were compared with cerebral blood flow, T2 and diffusion MRI from the same animal. Spatially, K(trans) changes were localized to superficial cortical layers within a 1mm thickness, which was dramatically different from the changes in cerebral blood flow, T2 and diffusion, which were localized to not only the superficial layers but also to brain regions up to 2.2mm from the cortical surface. Temporally, K(trans) changes peaked at day 3, similar to CBF and ADC changes, but differed from T2 and FA, whose changes peaked on day 2. The pattern of superficial cortical layer localization of K(trans) was consistent with patterns revealed by Evans Blue extravasation. Collectively, these results suggest that BBB disruption, edema formation, blood flow disturbance and diffusion changes are related to different components of the mechanical impact, and may play different roles in determining injury progression and tissue fate processes following TBI. PMID:27208495

  10. Radiohalogenated thienylethylamine derivatives for evaluating local cerebral blood flow

    SciTech Connect

    Goodman, M.M.; Knapp, F.F. Jr.

    1988-12-22

    An improved method of chemical synthesis of radiohalogenated thienylethylamine derivatives useful in brain imaging is described. These 5-halo-thiophene-2-isopropyl amines readily cross the blood- brain barrier and are retained in the brain for a sufficient length of time to allow evaluation of regional blood flow in the cerebrum. The advantages of the invention include a simpler synthesis route and a final compound which is less diluted with nonradioactive halogen. Use of this invention will allow clearer radioimaging or lower radiation doses to the patient, depending on the objective. 2 figs., 1 tab. (MHB)

  11. Oscillatory Cerebral Blood Flow Is Associated With Impaired Neurocognition And Functional Hyperemia In Postural Tachycardia Syndrome During Graded Tilt

    PubMed Central

    Stewart, Julian M.; Del Pozzi, Andrew T.; Pandey, Akash; Messer, Zachary R.; Terilli, Courtney; Medow, Marvin S.

    2014-01-01

    We hypothesize upright cognitive impairment in Postural Tachycardia Syndrome is due to reduced cerebral blood flow. Cerebral blood flow velocity measured by transcranial Doppler ultrasound decreased excessively during 70° tilt in a minority of patients with intermittent hyperpnea/hypocapnia. Incremental tilt showed no difference in mean cerebral blood flow velocity. But, N-Back memory tasking indicated progressive compromised memory, reduced functional hyperemia and reduced neurovascular coupling. Orthostasis caused slow oscillations in cerebral blood flow velocity linked to oscillations in arterial pressure in Postural Tachycardia Syndrome. We also hypothesize that oscillatory cerebral blood flow velocity degrades neurovascular coupling. We performed 2-Back testing supine and during incremental tilts to 15°, 30°, 45° and 60° in 11 Postural Tachycardia Syndrome and 9 controls. Oscillatory arterial pressure, oscillatory cerebral blood flow velocity and neurovascular coupling were similar supine. Oscillatory arterial pressure increased 31, 45, 67, and 93% in Postural Tachycardia Syndrome during tilt, remaining unchanged in control. Oscillatory cerebral blood flow velocity increased by 61, 82, 161, and 264% in Postural Tachycardia Syndrome during tilt remaining unchanged in control. Functional hyperemia decreased from 4.1% to 3.0, 1.1, 0.2, to 0.04% in Postural Tachycardia Syndrome but was unchanged at 4% in control. Percent correct N-Back responses decreased from 78% to 33% in Postural Tachycardia Syndrome while remaining at 89% in controls. In Postural Tachycardia Syndrome, oscillatory cerebral blood flow velocity was linearly correlated with functional hyperemia (r2=0.76). Increased oscillatory cerebral blood flow is associated with reduced neurovascular coupling and diminished cognitive performance in Postural Tachycardia Syndrome. PMID:25510829

  12. Altered phase interactions between spontaneous blood pressure and flow fluctuations in type 2 diabetes mellitus: Nonlinear assessment of cerebral autoregulation

    NASA Astrophysics Data System (ADS)

    Hu, Kun; Peng, C. K.; Huang, Norden E.; Wu, Zhaohua; Lipsitz, Lewis A.; Cavallerano, Jerry; Novak, Vera

    2008-04-01

    Cerebral autoregulation is an important mechanism that involves dilatation and constriction in arterioles to maintain relatively stable cerebral blood flow in response to changes of systemic blood pressure. Traditional assessments of autoregulation focus on the changes of cerebral blood flow velocity in response to large blood pressure fluctuations induced by interventions. This approach is not feasible for patients with impaired autoregulation or cardiovascular regulation. Here we propose a newly developed technique-the multimodal pressure-flow (MMPF) analysis, which assesses autoregulation by quantifying nonlinear phase interactions between spontaneous oscillations in blood pressure and flow velocity during resting conditions. We show that cerebral autoregulation in healthy subjects can be characterized by specific phase shifts between spontaneous blood pressure and flow velocity oscillations, and the phase shifts are significantly reduced in diabetic subjects. Smaller phase shifts between oscillations in the two variables indicate more passive dependence of blood flow velocity on blood pressure, thus suggesting impaired cerebral autoregulation. Moreover, the reduction of the phase shifts in diabetes is observed not only in previously-recognized effective region of cerebral autoregulation (<0.1 Hz), but also over the higher frequency range from ˜0.1 to 0.4 Hz. These findings indicate that type 2 diabetes mellitus alters cerebral blood flow regulation over a wide frequency range and that this alteration can be reliably assessed from spontaneous oscillations in blood pressure and blood flow velocity during resting conditions. We also show that the MMPF method has better performance than traditional approaches based on Fourier transform, and is more suitable for the quantification of nonlinear phase interactions between nonstationary biological signals such as blood pressure and blood flow.

  13. Preoperative preparation of the patient with the abnormalities of red and white blood cells.

    PubMed

    Tomin, Dragica

    2011-01-01

    The complete peripheral blood count analysis including laboratory screening tests of haemostasis and coagulation should be done in every patient before surgery, in order to detect specific abnormalities for primary or secundary haematologic disorder. These abnormalities might be very important course of perioperative and postoperative complications. Anaemia is the most frequent haematologic abnormality seen during preoperative period. Therapy approach depends on the type and anaemia degree, and also on the type and time of surgery. If surgery is not urgent specific therapy according to the anaemia type (iron therapy, vitamin B12, folic acid, corticosteroids, recombinant erythropoietin) should be given in all anaemias with deficiency of iron, megaloblastic anaemias, acquired haemolytic anaemias and anaemias in end stage renal disease. Transfusion of red cells are most frequently given in patients with normovolemic anaemias with haemoglobin level of 10.0 g/dl and hematocrit of 0.30, but lower levels in haemodynamic stable patients. Venesections should be done in patients with erythrocytosis in order to reduce total red cell volume, but taking into account the perioperative bleeding. Patients with leukocyte abnormalities suspected on primary haematologic disorder need urgent haematologic diagnostic procedures. In patients with leucocytosis the actual level of neutropenia is the bigger problem than the level of leucocytosis. In those patients treatment generally involves preventing infections, managing of febrile neutropenia with broad spectrum antibiotics and antifungal drugs, treatment with recombinant granulocyte hematopoetic factor, rarely transfusions of granulocyte concentrates and intravenous immunoglobulins. PMID:21879654

  14. Comparison of near-infrared spectroscopy with CT cerebral blood flow measurements in newborn piglets

    NASA Astrophysics Data System (ADS)

    Brown, Derek W.; Picot, Paul A.; Springett, Roger; Delpy, David T.; Lee, Ting-Yim

    2001-05-01

    Severely premature infants are often at high risk of cerebral hemorrhage or ischemic injury due to their inability to properly regulate blood flow to the brain. If blood flow is too high, the infant is at risk of cerebral hemorrhage, while too little blood flow can result in ischemic injury. The purpose of this research is to design and develop a means of non-invasively measuring cerebral blood flow (CBF) with near infrared spectroscopy (NIRS). Such a device would greatly aid the diagnosis and monitoring of afflicted infants. Previous attempts to measure CBF with NIRS have achieved limited success. In this study we acquired high signal-to-noise NIR spectrum from 600 to 980 nm with a cooled CCD spectrometer. This spectrometer enables the differential path length factor (DPF) to be estimated with accuracy using a second derivative technique described by Matcher et al. The validity of our new approach is determined via direct comparison with a previously validated computed tomography (CT) method. Three newborn piglets were studied. CBF measurements were performed at various partial arterial CO2 tensions (PaCO2) using both the NIRS and CT methods. The results of the two methods correlate well with a relationship of CBFCT equals -4.30 + 1.05 CBFNIRS (r2 equals 0.96).

  15. Evidence of redistribution of cerebral blood flow during treatment for an intracranial arteriovenous malformation

    SciTech Connect

    Batjer, H.H.; Purdy, P.D.; Giller, C.A.; Samson, D.S. )

    1989-10-01

    The presence of an intracranial arteriovenous malformation has a dramatic impact on local circulatory dynamics. Treatment of some arteriovenous malformations can result in disastrous hyperemic states caused by redistribution of previously shunted blood. This report describes serial hemodynamic measurements of both cerebral blood flow and flow velocity in 3 patients during treatment for arteriovenous malformations. Measurements of cerebral blood flow were made by computed tomographic scan employing the stable xenon inhalation technique; flow velocity, including autoregulatory characteristics, was measured by transcranial Doppler ultrasonogram. Substantial hyperemia developed in one patient (Case 1) after resection and in another (Case 3) after embolization. Embolization resulted in restoration of normal regional cerebral blood flow in a patient who demonstrated hypoperfusion before treatment (Case 2). In Patient 1, postoperative hyperemia was associated with persistently elevated flow velocities, and may have been accompanied by hemispheric neurological deficits. Sequential hemodynamic measurements may predict patients at risk of perioperative complications, and may become useful clinical guidelines for the extent and timing of embolization and for the timing of surgery after intracranial hemorrhage or preoperative embolization procedures.

  16. Effect of Vestibular Impairment on Cerebral Blood Flow Response to Dynamic Roll Tilt

    NASA Technical Reports Server (NTRS)

    Serrador, J. M.; Black, F. O.; Schlgel, Todd T.; Lipsitz, L. A.; Wood, S. J.

    2008-01-01

    Change to upright posture results in reductions in cerebral perfusion pressure due to hydrostatic pressure changes related to gravity. Since vestibular organs, specifically the otoliths, provide information on position relative to gravity, vestibular inputs may assist in adaptation to the upright posture. The goal of this study was to examine the effect of direct vestibular stimulation on cerebral blood flow (CBF). To examine the role of otolith inputs we screened 165 subjects for vestibular function and classified subjects as either normal or impaired based on ocular torsion. Ocular torsion, an indication of otolith function, was assessed during sinusoidal roll tilt of 20 degrees at 0.01 Hz (100 sec per cycle). Subjects with torsion one SD below the mean were classified as impaired while subjects one SD above the mean were considered normal. During one session subjects were placed in a chair that was sinusoidally rotated 25 degrees in the roll plane at five frequencies: 0.25 & 0.125 Hz for 80 sec, 0.0625 Hz for 160 sec and 0.03125 Hz and 0.015625 Hz for 320 sec. During testing, CBF (transcranial Doppler), blood pressure (Finapres), and end tidal CO2 (Puritan Bennet) were measured continuously. Ocular torsion was assessed from infrared images of the eyes. All rotations were done in the dark with subjects fixated on a red LED directly at the center of rotation. In the normal group, dynamic tilt resulted in significant changes in both blood pressure and cerebral blood flow velocity that was related to the frequency of stimulus. In contrast the impaired group did not show similar patterns. As expected normal subjects demonstrated significant ocular torsion that was related to stimulus frequency while impaired subjects had minimal changes. These data suggest that vestibular inputs have direct effects on cerebral blood flow regulation during dynamic tilt. Supported by NASA.

  17. Positron emission tomography in the newborn: extensive impairment of regional cerebral blood flow with intraventricular hemorrhage and hemorrhagic intracerebral involvement

    SciTech Connect

    Volpe, J.J.; Herscovitch, P.; Perlman, J.M.; Raichle, M.E.

    1983-11-01

    Positron emission tomography (PET) now provides the capability of measuring regional cerebral blood flow with high resolution and little risk. In this study, we utilized PET in six premature infants (920 to 1,200 g) with major intraventricular hemorrhage and hemorrhagic intracerebral involvement to measure regional cerebral blood flow during the acute period (5 to 17 days of age). Cerebral blood flow was determined after intravenous injection of H/sub 2/O, labeled with the positron-emitting isotope, /sup 15/O. Findings were similar and dramatic in all six infants. In the area of hemorrhagic intracerebral involvement, little or no cerebral blood flow was detected. However, in addition, surprisingly, a marked two- to fourfold reduction in cerebral blood flow was observed throughout the affected hemisphere, well posterior and lateral to the intracerebral hematoma, including cerebral white matter and, to a lesser extent, frontal, temporal, and parietal cortex. In the one infant studied a second time, ie, at 3 months of age, the extent and severity of the decreased cerebral blood flows in the affected hemisphere were similar to those observed on the study during the neonatal period. At the three autopsies, the affected left hemisphere showed extensive infarction, corroborating the PET scans. These observations, the first demonstration of the use of PET in the determination of regional cerebral blood flow in the newborn, show marked impairments in regional cerebral blood flow in the hemisphere containing an apparently restricted intracerebral hematoma, indicating that the hemorrhagic intracerebral involvement is only a component of a much larger lesion, ischemic in basic nature, ie, an infarction. This large ischemic lesion explains the poor neurologic outcome in infants with intraventricular hemorrhage and hemorrhagic intracerebral involvement.

  18. Effects of GSM 900 MHz on middle cerebral artery blood flow assessed by transcranial Doppler sonography.

    PubMed

    Ghosn, Rania; Thuróczy, György; Loos, Nathalie; Brenet-Dufour, Valérie; Liabeuf, Sophie; de Seze, René; Selmaoui, Brahim

    2012-12-01

    Mobile phone use has increased worldwide but its possible effects on the brain remain unclear. The aim of the present study was to investigate the effect of acute exposure to a radio frequency electromagnetic field (RF EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM) 900 MHz on cerebral blood flow. Twenty-nine volunteers attended two experimental sessions: a sham exposure session and a real exposure session in a cross-over double-blind study in which a mobile phone was positioned on the left side of the head. In one session, the mobile phone was operated without RF radiation (sham phone) and in the other study it was operated with RF radiation (real phone) for 20 min. Thus, each subject served as its own control. Middle cerebral artery blood flow was monitored noninvasively by transcranial Doppler sonography to measure middle cerebral artery blood flow velocity. Pulsatility index and resistance index were also evaluated. A voluntary breath holding physiological test was carried out as a positive control for testing cerebral vasoreactivity. Hemodynamic variables were recorded and analyzed before, during and after mobile phone exposure. No significant changes were detected in studied variables in middle cerebral arteries during sham or real exposure. In the exposed side the cerebral blood flow velocity, the pulsatility index and the resistance index during sham and real exposure were respectively: [61.9 ± 1.3, 61.7 ± 1.3 cm/s (P = 0.89)]; [0.93 ± 0.03, 0.90 ± 0.02 (P = 0.84)] and [0.58 ± 0.01, 0.58 ± 0.01 (P = 0.96)] at baseline; and [60.6 ± 1.3, 62 ± 1.6 cm/s (P = 0.40)]; [0.91 ± 0.03, 0.87 ± 0.03 (P = 0.97)]; [0.57 ± 0.01, 0.56 ± 0.01 (P = 0.82)] after 20 min of exposure. Twenty minutes of RF exposure to a mobile phone does not seem to affect the cerebral circulation. PMID:23106209

  19. Identification of abnormal motor cortex activation patterns in children with cerebral palsy by functional near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Khan, Bilal; Tian, Fenghua; Behbehani, Khosrow; Romero, Mario I.; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Reid, Dahlia; Liu, Hanli; Alexandrakis, George

    2010-05-01

    We demonstrate the utility of functional near-infrared spectroscopy (fNIRS) as a tool for physicians to study cortical plasticity in children with cerebral palsy (CP). Motor cortex activation patterns were studied in five healthy children and five children with CP (8.4+/-2.3 years old in both groups) performing a finger-tapping protocol. Spatial (distance from center and area difference) and temporal (duration and time-to-peak) image metrics are proposed as potential biomarkers for differentiating abnormal cortical activation in children with CP from healthy pediatric controls. In addition, a similarity image-analysis concept is presented that unveils areas that have similar activation patterns as that of the maximum activation area, but are not discernible by visual inspection of standard activation images. Metrics derived from the images presenting areas of similarity are shown to be sensitive identifiers of abnormal activation patterns in children with CP. Importantly, the proposed similarity concept and related metrics may be applicable to other studies for the identification of cortical activation patterns by fNIRS.

  20. Identification of abnormal motor cortex activation patterns in children with cerebral palsy by functional near-infrared spectroscopy

    PubMed Central

    Khan, Bilal; Tian, Fenghua; Behbehani, Khosrow; Romero, Mario I.; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Reid, Dahlia; Liu, Hanli; Alexandrakis, George

    2010-01-01

    We demonstrate the utility of functional near-infrared spectroscopy (fNIRS) as a tool for physicians to study cortical plasticity in children with cerebral palsy (CP). Motor cortex activation patterns were studied in five healthy children and five children with CP (8.4±2.3years old in both groups) performing a finger-tapping protocol. Spatial (distance from center and area difference) and temporal (duration and time-to-peak) image metrics are proposed as potential biomarkers for differentiating abnormal cortical activation in children with CP from healthy pediatric controls. In addition, a similarity image-analysis concept is presented that unveils areas that have similar activation patterns as that of the maximum activation area, but are not discernible by visual inspection of standard activation images. Metrics derived from the images presenting areas of similarity are shown to be sensitive identifiers of abnormal activation patterns in children with CP. Importantly, the proposed similarity concept and related metrics may be applicable to other studies for the identification of cortical activation patterns by fNIRS. PMID:20615010

  1. Blunted cerebral blood flow velocity in response to a nitric oxide donor in postural tachycardia syndrome

    PubMed Central

    Del Pozzi, Andrew T.; Pandey, Akash; Medow, Marvin S.; Messer, Zachary R.

    2014-01-01

    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. PMID:24878770

  2. Impaired cerebral blood flow and oxygenation during exercise in type 2 diabetic patients

    PubMed Central

    Kim, Yu-Sok; Seifert, Thomas; Brassard, Patrice; Rasmussen, Peter; Vaag, Allan; Nielsen, Henning B; Secher, Niels H; van Lieshout, Johannes J

    2015-01-01

    Endothelial vascular function and capacity to increase cardiac output during exercise are impaired in patients with type 2 diabetes (T2DM). We tested the hypothesis that the increase in cerebral blood flow (CBF) during exercise is also blunted and, therefore, that cerebral oxygenation becomes affected and perceived exertion increased in T2DM patients. We quantified cerebrovascular besides systemic hemodynamic responses to incremental ergometer cycling exercise in eight male T2DM and seven control subjects. CBF was assessed from the Fick equation and by transcranial Doppler-determined middle cerebral artery blood flow velocity. Cerebral oxygenation and metabolism were evaluated from the arterial-to-venous differences for oxygen, glucose, and lactate. Blood pressure was comparable during exercise between the two groups. However, the partial pressure of arterial carbon dioxide was lower at higher workloads in T2DM patients and their work capacity and increase in cardiac output were only ∽80% of that established in the control subjects. CBF and cerebral oxygenation were reduced during exercise in T2DM patients (P < 0.05), and they expressed a higher rating of perceived exertion (P < 0.05). In contrast, CBF increased ∽20% during exercise in the control group while the brain uptake of lactate and glucose was similar in the two groups. In conclusion, these results suggest that impaired CBF and oxygenation responses to exercise in T2DM patients may relate to limited ability to increase cardiac output and to reduced vasodilatory capacity and could contribute to their high perceived exertion. PMID:26109188

  3. Cerebral blood flow response pattern during balloon test occlusion of the internal carotid artery

    SciTech Connect

    Witt, J.P.; Yonas, H.; Jungreis, C.

    1994-05-01

    To evaluate the risk of temporary or permanent internal carotid artery occlusion. In 156 patients intraarterial balloon test occlusion in combination with a stable xenon-enhanced CT cerebral blood flow study was performed before radiologic or surgical treatment. All 156 patients passed the clinical balloon test occlusion and underwent a xenon study in combination with a second balloon test. Quantitative flow data were analyzed for absolute changes as well as changes in symmetry. Fourteen patients exhibited reduced flow values between 20 and 30 mL/100 g per minute, an absolute decrease in flow, and significant asymmetry in the middle cerebral artery territory during balloon test occlusion. These patients would be considered at high risk for cerebral infarction if internal carotid artery occlusion were to be performed. With one exception they belonged to a group (class I) of 61 patients who showed bilateral or ipsilateral flow decrease and significant asymmetry with lower flow on the side of occlusion. The other 95 patients, who showed a variety of cerebral blood flow response patterns including ipsilateral or bilateral flow increase, were at moderate (class II) or low (class III) stroke risk. In contrast to these findings, exclusively qualitative flow analysis failed to identify the patients at high risk: a threshold with an asymmetry index of 10% revealed only 16% specificity whereas an asymmetry index of 45% showed only 61% sensitivity for detection of low flow areas (<30 mL/100 g per minute). For achieving a minimal hemodynamic related-stroke rate associated with permanent clinical internal carotid artery occlusion we suggest integration of a thorough analysis of quantitative cerebral blood flow data before and during balloon test occlusion. 68 refs., 5 figs., 2 tabs.

  4. The effect of changes in cerebral blood flow on cognitive function during exercise

    PubMed Central

    Ogoh, Shigehiko; Tsukamoto, Hayato; Hirasawa, Ai; Hasegawa, Hiroshi; Hirose, Norikazu; Hashimoto, Takeshi

    2014-01-01

    Abstract No studies have identified the direct effect of changes in cerebral blood flow (CBF) on cognitive function at rest and during exercise. In this study, we manipulated CBF using hypercapnic gas to examine whether an increase in CBF improves cognitive function during prolonged exercise. The speed and the accuracy of cognitive function were assessed using the Stroop color‐word test. After the Stroop test at rest, the subjects began exercising on a cycling ergometer in which the workload was increased by 0.5 kilopond every minute until a target heart rate of 140 beats/min was achieved. Then, the subjects continued to cycle at a constant rate for 50 min. At four time points during the exercise (0, 10, 20, 50 min), the subjects performed a Stroop test with and without hypercapnic respiratory gas (2.0% CO2), with a random order of the exposures in the two tests. Despite a decrease in the mean blood flow velocity in the middle cerebral artery (MCA Vmean), the reaction time for the Stroop test gradually decreased during the prolonged exercise without any loss of performance accuracy. In addition, the hypercapnia‐induced increase in MCA Vmean produced neither changes in the reaction time nor error in the Stroop test during exercise. These findings suggest that the changes in CBF are unlikely to affect cognitive function during prolonged exercise. Thus, we conclude that improved cognitive function may be due to cerebral neural activation associated with exercise rather than global cerebral circulatory condition. PMID:25263210

  5. Rizatriptan does not change cerebral blood flow velocity during migraine attacks.

    PubMed

    Gori, S; Morelli, N; Bellini, G; Bonanni, E; Manca, L; Orlandi, G; Iudice, A; Murri, L

    2005-04-30

    Rizatriptan represents a major advance in the treatment of migraine attack: inhibition of peripheral trigeminal nerve and constriction of intracranial extracerebral blood vessels have been proposed as its main antimigraine mechanisms of action. Although many studies may suggest that rizatriptan causes highly selective vasoconstriction within intracranial extracerebral vessels (i.e., meningeal arteries), no literature data are available to date on possible cerebral hemodynamic changes in humans after treatment with rizatriptan. The aim of this study was to evaluate the effect of rizatriptan on cerebral blood flow velocity performing transcranial Doppler during spontaneous attacks of migraine without aura. Fourteen patients suffering from migraine without aura were monitored to evaluate mean flow velocity changes on both middle cerebral arteries during migraine attack 30 min before and 120 min after oral administration of rizatriptan 10mg. Monitoring was repeated for 30 min during the pain-free period. All patients turned out to be drug responders and no significant mean flow velocity changes were observed between the pain-free period and pre-treatment phase; besides no significant difference in mean flow velocity value have been detected between the periods after the drug administration during the attack versus both pre-treatment period and pain-free phase. These findings indicate that the antimigraine action of rizatriptan is not associated with clear intracranial cerebral hemodynamic changes and may support its cerebrovascular safety. PMID:15811594

  6. The effect of changes in cerebral blood flow on cognitive function during exercise.

    PubMed

    Ogoh, Shigehiko; Tsukamoto, Hayato; Hirasawa, Ai; Hasegawa, Hiroshi; Hirose, Norikazu; Hashimoto, Takeshi

    2014-09-01

    No studies have identified the direct effect of changes in cerebral blood flow (CBF) on cognitive function at rest and during exercise. In this study, we manipulated CBF using hypercapnic gas to examine whether an increase in CBF improves cognitive function during prolonged exercise. The speed and the accuracy of cognitive function were assessed using the Stroop color-word test. After the Stroop test at rest, the subjects began exercising on a cycling ergometer in which the workload was increased by 0.5 kilopond every minute until a target heart rate of 140 beats/min was achieved. Then, the subjects continued to cycle at a constant rate for 50 min. At four time points during the exercise (0, 10, 20, 50 min), the subjects performed a Stroop test with and without hypercapnic respiratory gas (2.0% CO2), with a random order of the exposures in the two tests. Despite a decrease in the mean blood flow velocity in the middle cerebral artery (MCA Vmean), the reaction time for the Stroop test gradually decreased during the prolonged exercise without any loss of performance accuracy. In addition, the hypercapnia-induced increase in MCA Vmean produced neither changes in the reaction time nor error in the Stroop test during exercise. These findings suggest that the changes in CBF are unlikely to affect cognitive function during prolonged exercise. Thus, we conclude that improved cognitive function may be due to cerebral neural activation associated with exercise rather than global cerebral circulatory condition. PMID:25263210

  7. Contribution of flow-dependent vasomotor mechanisms to the autoregulation of cerebral blood flow.

    PubMed

    Koller, Akos; Toth, Peter

    2012-01-01

    Regulation of cerebral blood flow (CBF) is the result of multilevel mechanisms to maintain the appropriate blood supply to the brain while having to comply with the limited space available in the cranium. The latter requirement is ensured by the autoregulation of CBF, in which the pressure-sensitive myogenic response is known to play a pivotal role. However, in vivo increases in pressure are accompanied by increases in flow; yet the effects of flow on the vasomotor tone of cerebral vessels are less known. Earlier studies showed flow-sensitive dilation and/or constriction or both, but no clear picture emerged. Recently, the important role of flow-sensitive mechanism(s) eliciting the constriction of cerebral vessels has been demonstrated. This review focuses on the effect of hemodynamic forces (especially intraluminal flow) on the vasomotor tone of cerebral vessels and the underlying cellular and molecular mechanisms. A novel concept of autoregulation of CBF is proposed, suggesting that (in certain areas of the cerebrovascular tree) pressure- and flow-induced constrictions together maintain an effective autoregulation, and that alterations in these mechanisms may contribute to the development of cerebrovascular disorders. Future studies are warranted to explore the signals, the details of signaling processes and the in vivo importance of these mechanisms. PMID:22739136

  8. OBESITY INCREASES BLOOD PRESSURE, CEREBRAL VASCULAR REMODELING, AND SEVERITY OF STROKE IN THE ZUCKER RAT

    PubMed Central

    Osmond, Jessica M.; Mintz, James D.; Dalton, Brian; Stepp, David W.

    2009-01-01

    Obesity is a risk factor for stroke, but the mechanisms by which obesity increases stroke risk are unknown. Because microvascular architecture contributes to the outcome of stroke, we hypothesized that middle cerebral arteries (MCA) from obese Zucker rats (OZR) undergo inward remodeling and develop increased myogenic tone compared to lean Zucker rats (LZR). We further hypothesized that OZR have an increased infarct following cerebral ischemia and that changes in vascular structure and function correlate with the development of hypertension in OZR. Blood pressure was measured by telemetery in LZR and OZR from 6 to 17 weeks of age. Vessel structure and function were assessed in isolated MCAs. Stroke damage was assessed after ischemia was induced for 60 minutes followed by 24 hours of reperfusion. While mean arterial pressure (MAP) was similar between young rats (6–8 weeks old), MAP was higher in adult (14–17 weeks old) OZR than LZR. MCAs from OZR had a smaller lumen diameter and increased myogenic vasoconstriction compared to those from LZR. Following ischemia, infarction was 58% larger in OZR than LZR. Prior to the development of hypertension, MCA myogenic reactity and lumen diameter as well as infarct size were similar between young LZR and OZR. Our results indicate that the MCAs of OZR undergo structural remodeling and that these rats have greater cerebral injury following cerebral ischemia. These cerebrovascular changes correlate with the development of hypertension and suggest that the increased blood pressure may be the major determinant for stroke risk in obese individuals. PMID:19104000

  9. The Effect of Hemorheologic Factors on Middle Cerebral Artery Blood Flow Velocity in Young Individuals.

    PubMed

    Ameriso, S F; Meiselman, H J; Saraj, A; Fisher, M

    1992-01-01

    Analysis of the effect of hemorheologic factors on middle cerebral artery (MCA) blood flow velocity in 55 healthy individuals aged 18 to 30 years demonstrated an inverse association between mean MCA blood flow velocity and hematocrit (r = -0.27, p < 0.05). This association was largely explained by the effect of whole-blood viscosity. Neither fibrinogen concentration nor plasma viscosity were significantly associated with MCA blood flow velocity in this group; this lack of a fibrinogen association is in contrast to results previously obtained in elderly individuals where an inverse association was observed. These findings thus demonstrate age-dependent differences in the relationship between fibrinogen and MCA blood flow velocity. PMID:27308856

  10. Measurement of cerebral blood flow rate and its relationship with brain function using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Wang, Yi; Zhao, Yuqian; Dou, Shidan; Ma, Yushu; Ma, Zhenhe

    2016-03-01

    Activity of brain neurons will lead to changes in local blood flow rate (BFR). Thus, it is important to measure the local BFR of cerebral cortex on research of neuron activity in vivo, such as rehabilitation evaluation after stroke, etc. Currently, laser Doppler flowmetry is commonly used for blood flow measurement, however, relatively low resolution limits its application. Optical coherence tomography (OCT) is a powerful noninvasive 3D imaging modality with high temporal and spatial resolutions. Furthermore, OCT can provide flow distribution image by calculating Doppler frequency shift which makes it possible for blood flow rate measurement. In this paper, we applied OCT to measure the blood flow rate of the primary motor cortex in rats. The animal was immobilized and anesthetized with isoflurane, an incision was made along the sagittal suture, and bone was exposed. A skull window was opened on the primary motor cortex. Then, blood flow rate changes in the primary motor cortex were monitored by our homemade spectral domain OCT with a stimulation of the passive movement of the front legs. Finally, we established the relationship between blood flow rate and the test design. The aim is to demonstrate the potential of OCT in the evaluation of cerebral cortex function.

  11. Do GSM 900MHz signals affect cerebral blood circulation? A near-infrared spectrophotometry study

    NASA Astrophysics Data System (ADS)

    Wolf, Martin; Haensse, Daniel; Morren, Geert; Froehlich, Juerg

    2006-06-01

    Effects of GSM 900MHz signals (EMF) typical for a handheld mobile phone on the cerebral blood circulation were investigated using near-infrared spectrophotometry (NIRS) in a three armed (12W/kg, 1.2W/kg, sham), double blind, randomized crossover trial in 16 healthy volunteers. During exposure we observed borderline significant short term responses of oxyhemoglobin and deoxyhemoglobin concentration, which correspond to a decrease of cerebral blood flow and volume and were smaller than regular physiological changes. Due to the relatively high number of statistical tests, these responses may be spurious and require further studies. There was no detectable dose-response relation or long term response within 20min. The detection limit was a fraction of the regular physiological changes elicited by functional activation. Compared to previous studies using PET, NIRS provides a much higher time resolution, which allowed investigating the short term effects efficiently, noninvasively, without the use of radioactive tracers and with high sensitivity.

  12. Application of Thinned-Skull Cranial Window to Mouse Cerebral Blood Flow Imaging Using Optical Microangiography

    PubMed Central

    Wang, Ruikang K.

    2014-01-01

    In vivo imaging of mouse brain vasculature typically requires applying skull window opening techniques: open-skull cranial window or thinned-skull cranial window. We report non-invasive 3D in vivo cerebral blood flow imaging of C57/BL mouse by the use of ultra-high sensitive optical microangiography (UHS-OMAG) and Doppler optical microangiography (DOMAG) techniques to evaluate two cranial window types based on their procedures and ability to visualize surface pial vessel dynamics. Application of the thinned-skull technique is found to be effective in achieving high quality images for pial vessels for short-term imaging, and has advantages over the open-skull technique in available imaging area, surgical efficiency, and cerebral environment preservation. In summary, thinned-skull cranial window serves as a promising tool in studying hemodynamics in pial microvasculature using OMAG or other OCT blood flow imaging modalities. PMID:25426632

  13. Assessment of cerebral blood flow autoregulation (CBF AR) with rheoencephalography (REG): studies in animals

    NASA Astrophysics Data System (ADS)

    Popovic, Djordje; Bodo, Michael; Pearce, Frederick; van Albert, Stephen; Garcia, Alison; Settle, Tim; Armonda, Rocco

    2013-04-01

    The ability of cerebral vasculature to regulate cerebral blood flow (CBF) in the face of changes in arterial blood pressure (SAP) or intracranial pressure (ICP) is an important guard against secondary ischemia in acute brain injuries, and official guidelines recommend that therapeutic decisions be guided by continuous monitoring of CBF autoregulation (AR). The common method for CBF AR monitoring, which rests on real-time derivation of the correlation coefficient (PRx) between slow oscillations in SAP and ICP is, however, rarely used in clinical practice because it requires invasive ICP measurements. This study investigated whether the correlation coefficient between SAP and the pulsatile component of the non-invasive transcranial bioimpedance signal (rheoencephalography, REG) could be used to assess the state and lower limit of CBF AR. The results from pigs and rhesus macaques affirm the utility of REG; however, additional animal and clinical studies are warranted to assess selectivity of automatic REG-based evaluation of CBF AR.

  14. Cerebral blood flow changes in acute experimental haemorrhagic vasospasm.

    PubMed

    Jakubowski, J; McCleery, W N; Todd, J H; Smart, R C

    1976-01-01

    Subarachnoid haemorrhage was produced in 26 dogs by injecting fresh homogenous blood into the cysterna chiasmatica. Two types of vasospasm were observed, firstly segmental arterial spasm closely related to the bleeding point and secondly generalized arterial vasospasm not directly related to the bleeding point and often occurring some way from the bleeding point. Reduction in CBF occurred in 61% of cases and was always accompanied by radiological vasospasm. However, in about one quarter of the cases with vasospasm there was no alteration in CBF. PMID:961484

  15. Diffuse correlation spectroscopy for non-invasive, micro-vascular cerebral blood flow measurement

    PubMed Central

    Durduran, Turgut; Yodh, Arjun G.

    2013-01-01

    Diffuse correlation spectroscopy (DCS) uses the temporal fluctuations of near-infrared (NIR) light to measure cerebral blood flow (CBF) non-invasively. Here, we provide a brief history of DCS applications in brain with an emphasis on the underlying physical ideas, common instrumentation and validation. Then we describe recent clinical research that employs DCS-measured CBF as a biomarker of patient well-being, and as an indicator of hemodynamic and metabolic response to functional stimuli. PMID:23770408

  16. Diffuse correlation spectroscopy for measurement of cerebral blood flow: future prospects

    PubMed Central

    Buckley, Erin M.; Parthasarathy, Ashwin B.; Grant, P. Ellen; Yodh, Arjun G.; Franceschini, Maria Angela

    2014-01-01

    Abstract. Diffuse correlation spectroscopy (DCS) is an emerging optical modality used to measure cortical cerebral blood flow. This outlook presents a brief overview of the technology, summarizing the advantages and limitations of the method, and describing its recent applications to animal, adult, and infant cohorts. At last, the paper highlights future applications where DCS may play a pivotal role individualizing patient management and enhancing our understanding of neurovascular coupling, activation, and brain development. PMID:25593978

  17. Effect of an acute increase in central blood volume on cerebral hemodynamics.

    PubMed

    Ogoh, Shigehiko; Hirasawa, Ai; Raven, Peter B; Rebuffat, Thomas; Denise, Pierre; Lericollais, Romain; Sugawara, Jun; Normand, Hervé

    2015-10-15

    Systemic blood distribution is an important factor involved in regulating cerebral blood flow (CBF). However, the effect of an acute change in central blood volume (CBV) on CBF regulation remains unclear. To address our question, we sought to examine the CBF and systemic hemodynamic responses to microgravity during parabolic flight. Twelve healthy subjects were seated upright and exposed to microgravity during parabolic flight. During the brief periods of microgravity, mean arterial pressure was decreased (-26 ± 1%, P < 0.001), despite an increase in cardiac output (+21 ± 6%, P < 0.001). During microgravity, central arterial pulse pressure and estimated carotid sinus pressure increased rapidly. In addition, this increase in central arterial pulse pressure was associated with an arterial baroreflex-mediated decrease in heart rate (r = -0.888, P < 0.0001) and an increase in total vascular conductance (r = 0.711, P < 0.001). The middle cerebral artery mean blood velocity (MCA Vmean) remained unchanged throughout parabolic flight (P = 0.30). During microgravity the contribution of cardiac output to MCA Vmean was gradually reduced (P < 0.05), and its contribution was negatively correlated with an increase in total vascular conductance (r = -0.683, P < 0.0001). These findings suggest that the acute loading of the arterial and cardiopulmonary baroreceptors by increases in CBV during microgravity results in acute and marked systemic vasodilation. Furthermore, we conclude that this marked systemic vasodilation decreases the contribution of cardiac output to CBF. These findings suggest that the arterial and cardiopulmonary baroreflex-mediated peripheral vasodilation along with dynamic cerebral autoregulation counteracts a cerebral overperfusion, which otherwise would occur during acute increases in CBV. PMID:26310936

  18. Multimodal Pressure-Flow Analysis: Application of Hilbert Huang Transform in Cerebral Blood Flow Regulation

    NASA Astrophysics Data System (ADS)

    Lo, Men-Tzung; Hu, Kun; Liu, Yanhui; Peng, C.-K.; Novak, Vera

    2008-12-01

    Quantification of nonlinear interactions between two nonstationary signals presents a computational challenge in different research fields, especially for assessments of physiological systems. Traditional approaches that are based on theories of stationary signals cannot resolve nonstationarity-related issues and, thus, cannot reliably assess nonlinear interactions in physiological systems. In this review we discuss a new technique called multimodal pressure flow (MMPF) method that utilizes Hilbert-Huang transformation to quantify interaction between nonstationary cerebral blood flow velocity (BFV) and blood pressure (BP) for the assessment of dynamic cerebral autoregulation (CA). CA is an important mechanism responsible for controlling cerebral blood flow in responses to fluctuations in systemic BP within a few heart-beats. The MMPF analysis decomposes BP and BFV signals into multiple empirical modes adaptively so that the fluctuations caused by a specific physiologic process can be represented in a corresponding empirical mode. Using this technique, we showed that dynamic CA can be characterized by specific phase delays between the decomposed BP and BFV oscillations, and that the phase shifts are significantly reduced in hypertensive, diabetics and stroke subjects with impaired CA. Additionally, the new technique can reliably assess CA using both induced BP/BFV oscillations during clinical tests and spontaneous BP/BFV fluctuations during resting conditions.

  19. Reproducibility of measuring cerebral blood flow by laser-Doppler flowmetry in mice.

    PubMed

    Tajima, Yosuke; Takuwa, Hiroyuki; Kawaguchi, Hiroshi; Masamoto, Kazuto; Ikoma, Yoko; Seki, Chie; Taniguchi, Junko; Kanno, Iwao; Saeki, Naokatsu; Ito, Hiroshi

    2014-01-01

    Laser-Doppler flowmetry has been widely used to trace hemodynamic changes in experimental stroke research. The purpose of the present study was to evaluate the day-to-day test-retest reproducibility of measuring cerebral blood flow by LDF in awake mice. The flux indicating cerebral blood flow (CBF), red blood cell (RBC) velocity, and RBC concentration were measured with LDF via cranial windows for the bilateral somatosensory cortex in awake mice. LDF measurements were performed three times, at baseline, 1 hour after, and 7 days after the baseline measurement. Moreover, breathing rate (BR) and partial pressure of transcutaneous CO₂ (PtCO₂) were measured simultaneously with LDF measurement. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (CVw) were calculated. CBF, RBC velocity, and RBC concentration showed good day-to-day test-retest reproducibility (ICC: 0.61 - 0.95, CVw: 8.3% - 15.4%). BR and PtCO₂ in awake mice were stable during the course of the experiments. The evaluation of cerebral microcirculation using LDF appears to be applicable to long-term studies. PMID:24389142

  20. Noninvasive Optical Measurement of Cerebral Blood Flow in Mice Using Molecular Dynamics Analysis of Indocyanine Green

    PubMed Central

    Ku, Taeyun; Choi, Chulhee

    2012-01-01

    In preclinical studies of ischemic brain disorders, it is crucial to measure cerebral blood flow (CBF); however, this requires radiological techniques with heavy instrumentation or invasive procedures. Here, we propose a noninvasive and easy-to-use optical imaging technique for measuring CBF in experimental small animals. Mice were injected with indocyanine green (ICG) via tail-vein catheterization. Time-series near-infrared fluorescence signals excited by 760 nm light-emitting diodes were imaged overhead by a charge-coupled device coupled with an 830 nm bandpass-filter. We calculated four CBF parameters including arrival time, rising time and mean transit time of a bolus and blood flow index based on time and intensity information of ICG fluorescence dynamics. CBF maps were generated using the parameters to estimate the status of CBF, and they dominantly represented intracerebral blood flows in mice even in the presence of an intact skull and scalp. We demonstrated that this noninvasive optical imaging technique successfully detected reduced local CBF during middle cerebral artery occlusion. We further showed that the proposed method is sufficiently sensitive to detect the differences between CBF status in mice anesthetized with either isoflurane or ketamine–xylazine, and monitor the dynamic changes in CBF after reperfusion during transient middle cerebral artery occlusion. The near-infrared optical imaging of ICG fluorescence combined with a time-series analysis of the molecular dynamics can be a useful noninvasive tool for preclinical studies of brain ischemia. PMID:23119000

  1. The functional role of the alpha-1 adrenergic receptors in cerebral blood flow regulation

    PubMed Central

    Purkayastha, Sushmita; Raven, Peter B.

    2011-01-01

    Cerebral vasculature is richly innervated by the α-1 adrenergic receptors similar to that of the peripheral vasculature. However, the functional role of the α-1adrenergic receptors in cerebral blood flow (CBF) regulation is yet to be established. The traditional thinking being that during normotension and normocapnia sympathetic neural activity does not play a significant role in CBF regulation. Reports in the past have stated that catecholamines do not penetrate the blood brain barrier (BBB) and therefore only influence cerebral vessels from outside the BBB and hence, have a limited role in CBF regulation. However, with the advent of dynamic measurement techniques, beat-to-beat CBF assessment can be done during dynamic changes in arterial blood pressure. Several studies in the recent years have reported a functional role of the α-1adrenergic receptors in CBF regulation. This review focuses on the recent developments on the role of the sympathetic nervous system, specifically that of the α-1 adrenergic receptors in CBF regulation. PMID:22021989

  2. Photoacoustic microscopy of cerebral blood-oxygenation dynamics in mice

    NASA Astrophysics Data System (ADS)

    Maslov, Konstantin; Stein, Erich W.; Wang, Lihong V.

    2009-02-01

    In this work, we exploit the high depth and temporal resolutions of PAM to noninvasively image the blood-oxygenation dynamics of multiple cortex vessels in the mouse brain simultaneously in response to controlled hypoxic and hyperoxic challenges. The dark-field photoacoustic microscopy (PAM) technique was enhanced to image the cortex vasculature of the mouse brain in vivo using endogenous hemoglobin contrast with one second temporal resolution. The maximum values of about 20% with standard deviation +/- 1.2% were found to vary significantly among the cortex vessels studied. The hypoxic response time to rise from 10 % to 90 % of maximum was 63 +/- 6 sec. The reverse response time for this event was 16 +/- 2 sec.

  3. Cerebral blood volume measured using near-infrared spectroscopy and radiolabels in the immature lamb brain.

    PubMed

    Barfield, C P; Yu, V Y; Noma, O; Kukita, J; Cussen, L J; Oates, A; Walker, A M

    1999-07-01

    Near-infrared spectroscopy (NIRS) is a technique that is increasingly being used for the noninvasive measurement of cerebral blood volume (CBV) in newborn infants, but it has not been fully validated against established methods. These experiments in immature lambs (gestation 92+/-1 d, mean+/-SEM) compared CBV measured using NIRS-derived estimates of oxygenated Hb (n = 5) with CBV estimated with radiolabeled indicators (125I-labeled serum albumin and 51Cr-labeled red blood cells, n = 10). Total brain CBV (mL/100 g tissue) measured using NIRS was 2.5+/-0.2 compared with 2.5+/-0.2 using radiolabels (NS). Regional tissue plasma, red blood cells, and whole blood volumes from radiolabels varied significantly (p < or = 0.05) throughout the brain. Whole blood volume (mL/100 g tissue) was largest in choroid plexus (16.2+/-2.1) and least in white matter (0.7+/-0.1) with a significant hierarchy evident among regions: choroid plexus > cerebellum > cortex > brain stem = midbrain > white matter. Regional plasma and red blood cell distributions were similar to whole blood, being highest in choroid plexus (13.0+/-1.6 and 3.2+/-0.9, respectively), and least in white matter (0.8+/-0.1 and 0, respectively). These data from the immature lamb brain indicate that total CBV measured with NIRS is essentially identical with the volumes obtained using intravascular radiolabels. Among cerebral regions, white matter contributes little to the global blood volume measured with NIRS because its red blood cell content is very low. PMID:10400134

  4. Impact of transient hypotension on regional cerebral blood flow in humans.

    PubMed

    Lewis, Nia C S; Smith, Kurt J; Bain, Anthony R; Wildfong, Kevin W; Numan, Tianne; Ainslie, Philip N

    2015-07-01

    We examined the impact of progressive hypotension with and without hypocapnia on regional extracranial cerebral blood flow (CBF) and intracranial velocities. Participants underwent progressive lower-body negative pressure (LBNP) until pre-syncope to inflict hypotension. End-tidal carbon dioxide was clamped at baseline levels (isocapnic trial) or uncontrolled (poikilocapnic trial). Middle cerebral artery (MCA) and posterior cerebral artery (PCA) blood velocities (transcranial Doppler; TCD), heart rate, blood pressure and end-tidal carbon dioxide were obtained continuously. Measurements of internal carotid artery (ICA) and vertebral artery (VA) blood flow (ICABF and VABF respectively) were also obtained. Overall, blood pressure was reduced by ~20% from baseline in both trials (P<0.001). In the isocapnic trial, end-tidal carbon dioxide was successfully clamped at baseline with hypotension, whereas in the poikilocapnic trial it was reduced by 11.1 mmHg (P<0.001) with hypotension. The decline in the ICABF with hypotension was comparable between trials (-139 ± 82 ml; ~30%; P<0.0001); however, the decline in the VABF was -28 ± 22 ml/min (~21%) greater in the poikilocapnic trial compared with the isocapnic trial (P=0.002). Regardless of trial, the blood flow reductions in ICA (-26 ± 14%) and VA (-27 ± 14%) were greater than the decline in MCA (-21 ± 15%) and PCA (-19 ± 10%) velocities respectively (P ≤ 0.01). Significant reductions in the diameter of both the ICA (~5%) and the VA (~7%) contributed to the decline in cerebral perfusion with systemic hypotension, independent of hypocapnia. In summary, our findings indicate that blood flow in the VA, unlike the ICA, is sensitive to changes hypotension and hypocapnia. We show for the first time that the decline in global CBF with hypotension is influenced by arterial constriction in the ICA and VA. Additionally, our findings suggest TCD measures of blood flow velocity may modestly underestimate changes in CBF during

  5. Development of a xenon/computed tomography cerebral blood flow quality assurance phantom

    SciTech Connect

    Good, W.F.; Gur, D.; Herron, J.M.; Kennedy, W.H.

    1987-09-01

    A simple, easy to use, quality assurance and performance test phantom was developed for the xenon/computed tomography (CT) cerebral blood flow method. The phantom combines an inhalation system which allows for the simulation of xenon buildup or washout in the arterial blood as well as a multisection translatable cylinder in which several sections can be scanned during a preselected protocol to simulate the CT enhancement in brain tissue during a study. The phantom and scanning protocol are described and their use is demonstrated. The results compare favorably to the theoretically expected fast, intermediate, and slow flow values designed into the phantom.

  6. Cerebrolysin effects on neurological outcomes and cerebral blood flow in acute ischemic stroke

    PubMed Central

    Amiri-Nikpour, Mohammad Reza; Nazarbaghi, Surena; Ahmadi-Salmasi, Babak; Mokari, Tayebeh; Tahamtan, Urya; Rezaei, Yousef

    2014-01-01

    Background Cerebrolysin, a brain-derived neuropeptide, has been shown to improve the neurological outcomes of stroke, but no study has demonstrated its effect on cerebral blood flow. This study aimed to determine the cerebrolysin impact on the neurological outcomes and cerebral blood flow. Methods In a randomized, double-blinded, placebo-controlled trial, 46 patients who had acute focal ischemic stroke were randomly assigned into two groups to receive intravenously either 30 mL of cerebrolysin diluted in normal saline daily for 10 days (n=23) or normal saline alone (n=23) adjunct to 100 mg of aspirin daily. All patients were examined using the National Institutes of Health Stroke Scale and transcranial Doppler to measure the mean flow velocity and pulsatility index (PI) of their cerebral arteries at baseline as well as on days 30, 60, and 90. Results The patients’ mean age was 60±9.7 years, and 51.2% of patients were male. The National Institutes of Health Stroke Scale was significantly lower in the cerebrolysin group compared with the placebo group on day 60 (median 10, interquartile range 9–11, P=0.008) and day 90 (median 11, interquartile range 10–13.5, P=0.001). The median of PI in the right middle cerebral artery was significantly lower in the cerebrolysin group compared with the placebo group on days 30, 60, and 90 (P<0.05). One patient in the cerebrolysin group and two patients in the placebo group died before day 30 (4.3% versus 8.7%). Conclusion Cerebrolysin can be useful to improve the neurological outcomes and the PI of middle cerebral artery in patients with acute focal ischemic stroke. PMID:25516711

  7. Inhibition of Rho Kinase (ROCK) Leads to Increased Cerebral Blood Flow and Stroke Protection

    PubMed Central

    Rikitake, Yoshiyuki; Kim, Hyung-Hwan; Huang, Zhihong; Seto, Minoru; Yano, Kazuo; Asano, Toshio; Moskowitz, Michael A.; Liao, James K.

    2009-01-01

    Background and Purpose Endothelium-derived nitric oxide (NO) plays a pivotal role in vascular protection. The Rho kinase (ROCK) inhibitor, hydroxyfasudil, prevents the downregulation of endothelial NO synthase (eNOS) under hypoxic conditions. However, it is unknown whether inhibition of ROCK can attenuate ischemia-induced endothelial dysfunction and tissue damage in vivo. Methods Human vascular endothelial cells were treated with increasing concentrations of hydroxyfasudil (0.1 to 100 μmol/L) and eNOS expression and activity were measured. To determine the physiological relevance of eNOS regulation by ROCK, we administered fasudil, which is metabolized to hydroxyfasudil in vivo, to mice for 2 days before subjecting them to middle cerebral artery occlusion. Cerebral blood flow, cerebral infarct size, and neurologic deficit were measured. Results In a concentration-dependent manner, hydroxyfasudil increased eNOS mRNA and protein expression, resulting in a 1.9- and 1.6-fold increase, respectively, at 10 μmol/L (P<0.05 for both). This correlated with a 1.5- and 2.3-fold increase in eNOS activity and NO production, respectively (P<0.05 for both). Fasudil increased cerebral blood flow to both ischemic and nonischemic brain areas, reduced cerebral infarct size by 33%, and improved neurologic deficit score by 37% (P<0.05). This correlated with inhibition of brain and vascular ROCK activity and increased eNOS expression and activity. Another ROCK inhibitor, Y-27632, also showed similar effects. The neuroprotective effects of fasudil were absent in eNOS-deficient mice. Conclusions These findings indicate that the neuroprotective effect of ROCK inhibition is mediated by endothelium-derived NO and suggest that ROCK may be an important therapeutic target for ischemic stroke. PMID:16141422

  8. External Counterpulsation Reduces Beat-to-Beat Blood Pressure Variability When Augmenting Blood Pressure and Cerebral Blood Flow in Ischemic Stroke

    PubMed Central

    Tian, Ge; Xiong, Li; Lin, Wenhua; Han, Jinghao; Chen, Xiangyan; Leung, Thomas Wai Hong; Soo, Yannie Oi Yan

    2016-01-01

    Background and Purpose External counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. Methods We enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04–0.15 Hz), and high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. Results We found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). Conclusions ECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies. PMID:27095525

  9. Short Term Outcome of Neonates Born With Abnormal Umbilical Cord Arterial Blood Gases

    PubMed Central

    Ahmadpour-Kacho, Mousa; Zahedpasha, Yadollah; Hagshenas, Mohsen; Akbarian Rad, Zahra; Sadat Nasseri, Bahram; Bijani, Ali

    2015-01-01

    Background: Umbilical arterial blood gas (UABG) analysis is more objective than other methods for predicting neonatal outcome. Acidemic neonates may be at risk for unfavorable outcome after birth, but all neonates with abnormal arterial blood gas (ABG) analysis do not always have poor outcome. Objectives: This study was carried out to determine the short term outcome of the neonates born with an abnormal ABG. Patients and Methods: In a cohort prospective study 120 high risk mother-neonate pairs were enrolled and UABG was taken immediately after birth. All neonates with an umbilical cord pH less than 7.2 were considered as case group and more than 7.2 as controls. Outcomes like need to resuscitation, admission to newborn services and/or NICU), seizure occurrence, hypoxic ischemic encephalopathy (HIE), delayed initiation of oral feeding and length of hospital stay were recorded and compared between the two groups. P value less than 0.05 was considered as being significant. Results: Comparison of short term outcomes between normal and abnormal ABG groups were as the fallowing: need for advanced resuscitation 4 vs. 0 (P = 0.001), NICU admission 16 vs. 4 (P = 0.001), convulsion 2 vs. 0 (P = 0.496), HIE 17 vs. 4 (P = 0.002), delay to start oral feeding 16 vs. 4 (P = 0.001), mean hospital stay 4 vs. 3 days (P = 0.001). None of the neonates died in study groups. Conclusions: An umbilical cord PH less than 7.2 immediately after birth can be used as a prognostic factor for unfavorable short term outcome in newborns. PMID:26199700

  10. Differentiation of abnormal blood flow patterns in coronary arteries based on Doppler catheter recordings.

    PubMed

    Denardo, S J; Yock, P G; Hargrave, V K; Srebro, J P; Ports, T A; Talbot, L

    1991-09-01

    Abnormal arterial blood flow patterns have been implicated as etiologic factors in thrombosis and atherosclerosis. Intravascular pulsed Doppler ultrasound techniques with fast-Fourier transform analysis offer the opportunity to measure these abnormalities. The authors hypothesized that statistical analysis of radial-directed beam spectra could be used to distinguish disturbed from non-disturbed flow and that analysis of conventional axial-directed beam spectra could then be used to distinguish laminar high-shear from laminar low-shear flow. They developed a scaled-up in-vitro model of coronary flow consisting of a glycerol/H2O test fluid flowing through an acrylic cylinder at Reynolds numbers spanning the typical physiologic range within the coronary arteries. A scaled-up Doppler catheter with the capacity for 90 degrees reflection of the beam was placed centrally. Disturbed flow was created by introducing a flow screen, and altered shear rates were produced by changing the Reynolds number. For the radial-directed beam studies, the coefficients of variation of the Doppler spectra for the disturbed flow states were significantly greater than for the nondisturbed flow states (p less than 0.01). For the axial-directed beam studies, the coefficients of variation of the Doppler spectra for the laminar high-shear flow states were significantly greater than for the laminar low-shear flow states (p less than 0.01). They conclude that abnormal blood flow patterns can be differentiated by the selective use of radial-directed and axial-directed Doppler catheter recordings. PMID:1928812

  11. Transcriptional Abnormalities of Hamstring Muscle Contractures in Children with Cerebral Palsy

    PubMed Central

    Smith, Lucas R.; Chambers, Henry G.; Subramaniam, Shankar; Lieber, Richard L.

    2012-01-01

    Cerebral palsy (CP) is an upper motor neuron disease that results in a spectrum of movement disorders. Secondary to the neurological lesion, muscles from patients with CP are often spastic and form debilitating contractures that limit range of motion and joint function. With no genetic component, the pathology of skeletal muscle in CP is a response to aberrant complex neurological input in ways that are not fully understood. This study was designed to gain further understanding of the skeletal muscle response in CP using transcriptional profiling correlated with functional measures to broadly investigate muscle adaptations leading to mechanical deficits. Biospsies were obtained from both the gracilis and semitendinosus muscles from a cohort of patients with CP (n = 10) and typically developing patients (n = 10) undergoing surgery. Biopsies were obtained to define the unique expression profile of the contractures and passive mechanical testing was conducted to determine stiffness values in previously published work. Affymetrix HG-U133A 2.0 chips (n = 40) generated expression data, which was validated for selected transcripts using quantitative real-time PCR. Chips were clustered based on their expression and those from patients with CP clustered separately. Significant genes were determined conservatively based on the overlap of three summarization algorithms (n = 1,398). Significantly altered genes were analyzed for over-representation among gene ontologies and muscle specific networks. The majority of altered transcripts were related to increased extracellular matrix expression in CP and a decrease in metabolism and ubiquitin ligase activity. The increase in extracellular matrix products was correlated with mechanical measures demonstrating the importance in disability. These data lay a framework for further studies and development of novel therapies. PMID:22956992

  12. Influence of high altitude on cerebral blood flow and fuel utilization during exercise and recovery

    PubMed Central

    Smith, K J; MacLeod, D; Willie, C K; Lewis, N C S; Hoiland, R L; Ikeda, K; Tymko, M M; Donnelly, J; Day, T A; MacLeod, N; Lucas, S J E; Ainslie, P N

    2014-01-01

    We examined the hypotheses that: (1) during incremental exercise and recovery following 4–6 days at high altitude (HA) global cerebral blood flow (gCBF) increases to preserve cerebral oxygen delivery () in excess of that required by an increasing cerebral metabolic rate of oxygen (); (2) the trans-cerebral exchange of oxygen vs. carbohydrates (OCI; carbohydrates = glucose + ½lactate) would be similar during exercise and recovery at HA and sea level (SL). Global CBF, intra-cranial arterial blood velocities, extra-cranial blood flows, and arterial–jugular venous substrate differences were measured during progressive steady-state exercise (20, 40, 60, 80, 100% maximum workload (Wmax)) and through 30 min of recovery. Measurements (n = 8) were made at SL and following partial acclimatization to 5050 m. At HA, absolute Wmax was reduced by ∼50%. During submaximal exercise workloads (20–60% Wmax), despite an elevated absolute gCBF (∼20%, P < 0.05) the relative increases in gCBF were not different at HA and SL. In contrast, gCBF was elevated at HA compared with SL during 80 and 100% Wmax and recovery. Notwithstanding a maintained and elevated absolute at HA compared with SL, the relative increase in was similar during 20–80% Wmax but half that of the SL response (i.e. 17 vs. 27%; P < 0.05 vs. SL) at 100% Wmax. The OCI was reduced at HA compared with SL during 20, 40, and 60% Wmax but comparable at 80 and 100% Wmax. At HA, OCI returned almost immediately to baseline values during recovery, whereas at SL it remained below baseline. In conclusion, the elevations in gCBF during exercise and recovery at HA serve to maintain . Despite adequate at HA the brain appears to increase non-oxidative metabolism during exercise and recovery. PMID:25362150

  13. Perihematoma cerebral blood flow is unaffected by statin use in acute intracerebral hemorrhage patients.

    PubMed

    Gioia, Laura C; Kate, Mahesh; McCourt, Rebecca; Gould, Bronwen; Coutts, Shelagh B; Dowlatshahi, Dariush; Asdaghi, Negar; Jeerakathil, Thomas; Hill, Michael D; Demchuk, Andrew M; Buck, Brian; Emery, Derek; Shuaib, Ashfaq; Butcher, Kenneth

    2015-07-01

    Statin therapy has been associated with improved cerebral blood flow (CBF) and decreased perihematoma edema in animal models of intracerebral hemorrhage (ICH). We aimed to assess the relationship between statin use and cerebral hemodynamics in ICH patients. A post hoc analysis of 73 ICH patients enrolled in the Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial (ICH ADAPT). Patients presenting <24 hours from ICH onset were randomized to a systolic blood pressure target <150 or <180 mm Hg with computed tomography perfusion imaging 2 hours after randomization. Cerebral blood flow maps were calculated. Hematoma and edema volumes were measured planimetrically. Regression models were used to assess the relationship between statin use, perihematoma edema and cerebral hemodynamics. Fourteen patients (19%) were taking statins at the time of ICH. Statin-treated patients had similar median (IQR Q25 to 75) hematoma volumes (21.1 (9.5 to 38.3) mL versus 14.5 (5.6 to 27.7) mL, P=0.25), but larger median (IQR Q25 to 75) perihematoma edema volumes (2.9 (1.7 to 9.0) mL versus 2.2 (0.8 to 3.5) mL, P=0.02) compared with nontreated patients. Perihematoma and ipsilateral hemispheric CBF were similar in both groups. A multivariate linear regression model revealed that statin use and hematoma volumes were independent predictors of acute edema volumes. Statin use does not affect CBF in ICH patients. Statin use, along with hematoma volume, are independently associated with increased perihematoma edema volume. PMID:25757757

  14. Perihematoma cerebral blood flow is unaffected by statin use in acute intracerebral hemorrhage patients

    PubMed Central

    Gioia, Laura C; Kate, Mahesh; McCourt, Rebecca; Gould, Bronwen; Coutts, Shelagh B; Dowlatshahi, Dariush; Asdaghi, Negar; Jeerakathil, Thomas; Hill, Michael D; Demchuk, Andrew M; Buck, Brian; Emery, Derek; Shuaib, Ashfaq; Butcher, Kenneth

    2015-01-01

    Statin therapy has been associated with improved cerebral blood flow (CBF) and decreased perihematoma edema in animal models of intracerebral hemorrhage (ICH). We aimed to assess the relationship between statin use and cerebral hemodynamics in ICH patients. A post hoc analysis of 73 ICH patients enrolled in the Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial (ICH ADAPT). Patients presenting <24 hours from ICH onset were randomized to a systolic blood pressure target <150 or <180 mm Hg with computed tomography perfusion imaging 2 hours after randomization. Cerebral blood flow maps were calculated. Hematoma and edema volumes were measured planimetrically. Regression models were used to assess the relationship between statin use, perihematoma edema and cerebral hemodynamics. Fourteen patients (19%) were taking statins at the time of ICH. Statin-treated patients had similar median (IQR Q25 to 75) hematoma volumes (21.1 (9.5 to 38.3) mL versus 14.5 (5.6 to 27.7) mL, P=0.25), but larger median (IQR Q25 to 75) perihematoma edema volumes (2.9 (1.7 to 9.0) mL versus 2.2 (0.8 to 3.5) mL, P=0.02) compared with nontreated patients. Perihematoma and ipsilateral hemispheric CBF were similar in both groups. A multivariate linear regression model revealed that statin use and hematoma volumes were independent predictors of acute edema volumes. Statin use does not affect CBF in ICH patients. Statin use, along with hematoma volume, are independently associated with increased perihematoma edema volume. PMID:25757757

  15. A subanesthetic concentration of sevoflurane increases regional cerebral blood flow and regional cerebral blood volume and decreases regional mean transit time and regional cerebrovascular resistance in volunteers.

    PubMed

    Kolbitsch, C; Lorenz, I H; Hörmann, C; Schocke, M; Kremser, C; Zschiegner, F; Löckinger, A; Pfeiffer, K P; Felber, S; Benzer, A

    2000-07-01

    Inhaled anesthetics exert metabolically mediated effects on cerebral blood vessels both directly and indirectly. We investigated the effects of a 0.4 minimum alveolar subanesthetic concentration of sevoflurane on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), regional cerebrovascular resistance (rCVR), and regional mean transit time (rMTT) in volunteers by means of contrast-enhanced magnetic resonance imaging perfusion measurement. Sevoflurane increased rCBF by 16% to 55% (control, 55. 03 +/- 0.33 to 148.83 +/- 1.9 mL. 100 g(-1). min(-1); sevoflurane, 71.75 +/- 0.36 to 193.26 +/- 2.14 mL. 100 g(-1). min(-1)) and rCBV by 7% to 39% (control, 4.66 +/- 0.03 to 10.04 +/- 0.12 mL/100 g; sevoflurane, 5.04 +/- 0.03 to 13.6 +/- 0.15 mL/100 g); however, sevoflurane decreased rMTT by 7% to 18% (control, 3.75 +/- 0.04 to 5. 39 +/- 0.04 s; sevoflurane, 3.4 +/- 0.03 to 4.44 +/- 0.03 s) and rCVR by 22% to 36% (control, 0.74 +/- 0.01 to 1.9 +/- 0.2 mm Hg/[mL. 100 g(-1). min(-1)]; sevoflurane, 0.54 +/- 0.01 to 1.41 +/- 0.01 mm Hg/[mL. 100 g(-1). min(-1)]). Interhemispheric differences in rCBF, rCBV, and rCVR were markedly reduced after the administration of sevoflurane. These findings are consistent with the known direct vasodilating effect of sevoflurane. The decrease in rMTT further shows that rCBF increases more than does rCBV. Furthermore, we can show that the observed increase in rCBF during inhalation of sevoflurane is not explained by vasodilation alone. PMID:10866904

  16. Substantial Reduction of Parenchymal Cerebral Blood Flow in Mice with Bilateral Common Carotid Artery Stenosis.

    PubMed

    Hattori, Yorito; Enmi, Jun-Ichiro; Iguchi, Satoshi; Saito, Satoshi; Yamamoto, Yumi; Nagatsuka, Kazuyuki; Iida, Hidehiro; Ihara, Masafumi

    2016-01-01

    The bilateral common carotid artery stenosis (BCAS) mouse model, which replicates chronic cerebral hypoperfusion and white matter ischemic lesions, is considered to model some aspects of vascular cognitive impairment. Cerebral blood flow (CBF) changes in the brain surface post-BCAS have been demonstrated by laser speckle flowmetry, but CBF levels in the brain parenchyma remain unknown. Adult C57BL/6J male mice were subjected to BCAS using external microcoils. Brain magnetic resonance angiography (MRA) was conducted to visualize the intracranial main arteries while arterial spin labeling (ASL) was used to measure cortical and subcortical parenchymal CBF levels before and after BCAS. Brain MRA showed anterior circulation flow was substantially decreased until 14 days post-BCAS, which gradually but incompletely recovered over the following 14 days, with probable growth of collaterals from the posterior cerebral artery. ASL showed that cortical and subcortical parenchymal CBF remained decreased at approximately 50% of the baseline level during 1 and 14 days post-BCAS, recovering to approximately 70% at day 28. CBF levels in the parenchyma were lower than the cortical superficial region in the BCAS model and remained decreased without recovery during the first 2 weeks post-BCAS. These results suggest that the BCAS model reliably replicates chronic cerebral hypoperfusion. PMID:27535801

  17. Nitric oxide, prostaglandins, and impaired cerebral blood flow autoregulation in group B streptococcal neonatal meningitis.

    PubMed

    Mertineit, C; Samlalsingh-Parker, J; Glibetic, M; Ricard, G; Noya, F J; Aranda, J V

    2000-03-01

    Impaired autoregulation of cerebral blood flow (CBF) contributes to CNS damage during neonatal meningitis. We tested (i) the hypothesis that cerebrovascular autoregulation is impaired during early onset group B streptococcal (GBS) meningitis, (ii) whether this impairment is regulated by vasoactive mediators such as prostaglandins and (or) nitric oxide (NO), and (iii) whether this impairment is preventable by specific and (or) nonspecific inhibitors: dexamethasone, ibuprofen, and Nomega-nitro-L-arginine, a NO inhibitor. Sterile saline or 10(9) colony-forming units (cfu) of heat-killed GBS was injected into the cerebral ventricle of newborn piglets. CBF autoregulation was determined by altering cerebral perfusion pressure (CPP) with balloon-tipped catheters placed in the aorta. GBS produced a narrow range of CBF autoregulation due to an impairment at the upper limit of CPP. We report that in vivo in the early stages (first 2 h) of induced GBS inflammation (i) GBS impairs the upper limit of cerebrovascular autoregulation; (ii) ibuprofen, dexamethasone, and Nomega-nitro-L-arginine not only prevent this GBS-induced autoregulatory impairment but improve the range of cerebrovascular autoregulation; (iii) these autoregulatory changes do not involve circulating cerebral prostanoids; and (iv) the observed changes correlate with the induction of NO synthase gene expression. Thus, acute early onset GBS-induced impairment of the upper limit of CBF autoregulation can be correlated with increases of NO synthase production, suggesting that NO is a vasoactive mediator of CBF. PMID:10721813

  18. Serum response factor and myocardin mediate arterial hypercontractility and cerebral blood flow dysregulation in Alzheimer's phenotype

    PubMed Central

    Chow, Nienwen; Bell, Robert D.; Deane, Rashid; Streb, Jeffrey W.; Chen, Jiyuan; Brooks, Andrew; Van Nostrand, William; Miano, Joseph M.; Zlokovic, Berislav V.

    2007-01-01

    Cerebral angiopathy contributes to cognitive decline and dementia in Alzheimer's disease (AD) through cerebral blood flow (CBF) reductions and dysregulation. We report vascular smooth muscle cells (VSMC) in small pial and intracerebral arteries, which are critical for CBF regulation, express in AD high levels of serum response factor (SRF) and myocardin (MYOCD), two interacting transcription factors that orchestrate a VSMC-differentiated phenotype. Consistent with this finding, AD VSMC overexpressed several SRF-MYOCD-regulated contractile proteins and exhibited a hypercontractile phenotype. MYOCD overexpression in control human cerebral VSMC induced an AD-like hypercontractile phenotype and diminished both endothelial-dependent and -independent relaxation in the mouse aorta ex vivo. In contrast, silencing SRF normalized contractile protein content and reversed a hypercontractile phenotype in AD VSMC. MYOCD in vivo gene transfer to mouse pial arteries increased contractile protein content and diminished CBF responses produced by brain activation in wild-type mice and in two AD models, the Dutch/Iowa/Swedish triple mutant human amyloid β-peptide (Aβ)-precursor protein (APP)- expressing mice and APPsw+/− mice. Silencing Srf had the opposite effect. Expression of SRF did not change in VSMC subjected to Alzheimer's neurotoxin, Aβ. Thus, SRF-MYOCD overexpression in small cerebral arteries appears to initiate independently of Aβ a pathogenic pathway mediating arterial hypercontractility and CBF dysregulation, which are associated with Alzheimer's dementia. PMID:17215356

  19. Substantial Reduction of Parenchymal Cerebral Blood Flow in Mice with Bilateral Common Carotid Artery Stenosis

    PubMed Central

    Hattori, Yorito; Enmi, Jun-ichiro; Iguchi, Satoshi; Saito, Satoshi; Yamamoto, Yumi; Nagatsuka, Kazuyuki; Iida, Hidehiro; Ihara, Masafumi

    2016-01-01

    The bilateral common carotid artery stenosis (BCAS) mouse model, which replicates chronic cerebral hypoperfusion and white matter ischemic lesions, is considered to model some aspects of vascular cognitive impairment. Cerebral blood flow (CBF) changes in the brain surface post-BCAS have been demonstrated by laser speckle flowmetry, but CBF levels in the brain parenchyma remain unknown. Adult C57BL/6J male mice were subjected to BCAS using external microcoils. Brain magnetic resonance angiography (MRA) was conducted to visualize the intracranial main arteries while arterial spin labeling (ASL) was used to measure cortical and subcortical parenchymal CBF levels before and after BCAS. Brain MRA showed anterior circulation flow was substantially decreased until 14 days post-BCAS, which gradually but incompletely recovered over the following 14 days, with probable growth of collaterals from the posterior cerebral artery. ASL showed that cortical and subcortical parenchymal CBF remained decreased at approximately 50% of the baseline level during 1 and 14 days post-BCAS, recovering to approximately 70% at day 28. CBF levels in the parenchyma were lower than the cortical superficial region in the BCAS model and remained decreased without recovery during the first 2 weeks post-BCAS. These results suggest that the BCAS model reliably replicates chronic cerebral hypoperfusion. PMID:27535801

  20. Mononuclear cells from the cord blood and granulocytecolony stimulating factor-mobilized peripheral blood: is there a potential for treatment of cerebral palsy?

    PubMed Central

    Koh, Hani; Hwang, Kyoujung; Lim, Hae-Young; Kim, Yong-Joo; Lee, Young-Ho

    2015-01-01

    To investigate a possible therapeutic mechanism of cell therapy in the field of cerebral palsy using granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (mPBMCs), we compared the expression of inflammatory cytokines and neurotrophic factors in PBMCs and mPBMCs from children with cerebral palsy to those from healthy adult donors and to cord blood mononuclear cells donated from healthy newborns. No significant differences in expression of neurotrophic factors were found between PBMCs and mPBMCs. However, in cerebral palsy children, the expression of interleukin-6 was significantly increased in mPBMCs as compared to PBMCs, and the expression of interleukin-3 was significantly decreased in mPBMCs as compared to PBMCs. In healthy adults, the expression levels of both interleukin-1β and interleukin-6 were significantly increased in mPBMCs as compared to PBMCs. The expression of brain-derived neurotrophic factors in mPBMC from cerebral palsy children was significantly higher than that in the cord blood or mPBMCs from healthy adults. The expression of G-CSF in mPBMCs from cerebral palsy children was comparable to that in the cord blood but significantly higher than that in mPBMCs from healthy adults. Lower expression of pro-inflammatory cytokines (interleukin-1β, interleukin-3, and -6) and higher expression of anti-inflammatory cytokines (interleukin-8 and interleukin-9) were observed from the cord blood and mPBMCs from cerebral palsy children rather than from healthy adults. These findings indicate that mPBMCs from cerebral palsy and cord blood mononuclear cells from healthy newborns have the potential to become seed cells for treatment of cerebral palsy. PMID:26889193

  1. Dehydration accelerates reductions in cerebral blood flow during prolonged exercise in the heat without compromising brain metabolism.

    PubMed

    Trangmar, Steven J; Chiesa, Scott T; Llodio, Iñaki; Garcia, Benjamin; Kalsi, Kameljit K; Secher, Niels H; González-Alonso, José

    2015-11-01

    Dehydration hastens the decline in cerebral blood flow (CBF) during incremental exercise, whereas the cerebral metabolic rate for O2 (CMRO2 ) is preserved. It remains unknown whether CMRO2 is also maintained during prolonged exercise in the heat and whether an eventual decline in CBF is coupled to fatigue. Two studies were undertaken. In study 1, 10 male cyclists cycled in the heat for ∼2 h with (control) and without fluid replacement (dehydration) while internal and external carotid artery blood flow and core and blood temperature were obtained. Arterial and internal jugular venous blood samples were assessed with dehydration to evaluate CMRO2 . In study 2, in 8 male subjects, middle cerebral artery blood velocity was measured during prolonged exercise to exhaustion in both dehydrated and euhydrated states. After a rise at the onset of exercise, internal carotid artery flow declined to baseline with progressive dehydration (P < 0.05). However, cerebral metabolism remained stable through enhanced O2 and glucose extraction (P < 0.05). External carotid artery flow increased for 1 h but declined before exhaustion. Fluid ingestion maintained cerebral and extracranial perfusion throughout nonfatiguing exercise. During exhaustive exercise, however, euhydration delayed but did not prevent the decline in cerebral perfusion. In conclusion, during prolonged exercise in the heat, dehydration accelerates the decline in CBF without affecting CMRO2 and also restricts extracranial perfusion. Thus, fatigue is related to a reduction in CBF and extracranial perfusion rather than CMRO2 . PMID:26371170

  2. Cerebral blood flow assessment of preterm infants during respiratory therapy with the expiratory flow increase technique

    PubMed Central

    Bassani, Mariana Almada; Caldas, Jamil Pedro Siqueira; Netto, Abimael Aranha; Marba, Sérgio Tadeu Martins

    2016-01-01

    Abstract Objective: To assess the impact of respiratory therapy with the expiratory flow increase technique on cerebral hemodynamics of premature newborns. Methods: This is an intervention study, which included 40 preterm infants (≤34 weeks) aged 8-15 days of life, clinically stable in ambient air or oxygen catheter use. Children with heart defects, diagnosis of brain lesion and/or those using vasoactive drugs were excluded. Ultrasonographic assessments with transcranial Doppler flowmetry were performed before, during and after the increase in expiratory flow session, which lasted 5min. Cerebral blood flow velocity and resistance and pulsatility indices in the pericallosal artery were assessed. Results: Respiratory physical therapy did not significantly alter flow velocity at the systolic peak (p=0.50), the end diastolic flow velocity (p=0.17), the mean flow velocity (p=0.07), the resistance index (p=0.41) and the pulsatility index (p=0.67) over time. Conclusions: The expiratory flow increase technique did not affect cerebral blood flow in clinically-stable preterm infants. PMID:26611888

  3. Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography.

    PubMed

    Qi, Li; Zhu, Jiang; Hancock, Aneeka M; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D; Chen, Zhongping

    2016-02-01

    Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement. PMID:26977365

  4. Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography

    PubMed Central

    Qi, Li; Zhu, Jiang; Hancock, Aneeka M.; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D.; Chen, Zhongping

    2016-01-01

    Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement. PMID:26977365

  5. Angiogenesis of the blood-brain barrier in vitro and the function of cerebral pericytes.

    PubMed

    Ramsauer, Markus; Krause, Dorothee; Dermietzel, Rolf

    2002-08-01

    Cerebral pericytes constitute an essential component of the blood-brain barrier (BBB) and are involved in blood vessel assembly. Recently, we reported on the induction of a BBB-specific enzyme expressed by cerebral pericytes (pericytic aminopeptidase N/pAPN) in coculture with cerebral endothelial cells. We completed this in vitro BBB system by adding astrocytes to these mixed cultures of endothelial cells and pericytes. Under these triculture conditions, endothelial cells and pericytes reorganize into capillary-like structures (CLSs). Capillary formation can also be achieved by the application of transforming growth factor beta 1 (TGF-b1) in the culture medium of endothelial-pericyte cultures lacking astrocytes. In contrast to the effect achieved by astrocytes, pericytes did not assemble with endothelial cells. In both cases (application of astrocytes or TGF-b1), endothelial cells underwent apoptosis. However, endothelial cells that form CLSs in the presence of pericytes appeared to be resistant to induction of apoptosis. On the basis of these observations, we concluded that astrocytes have a profound influence on the morphogenetic events underlying the organization of the vessel wall; that the effect of TGF-b1 is different from the astrocytic effect because it lacks induction of endothelial-pericyte association; and that pericytes stabilize CLSs formed by endothelial cells in coculture with astrocytes. PMID:12153997

  6. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods.

    PubMed

    Fantini, Sergio; Sassaroli, Angelo; Tgavalekos, Kristen T; Kornbluth, Joshua

    2016-07-01

    Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation. PMID:27403447

  7. Numerical validation of MR-measurement-integrated simulation of blood flow in a cerebral aneurysm.

    PubMed

    Funamoto, Kenichi; Suzuki, Yoshitsugu; Hayase, Toshiyuki; Kosugi, Takashi; Isoda, Haruo

    2009-06-01

    This study proposes magnetic resonance (MR)-measurement-integrated (MR-MI) simulation, in which the difference between the computed velocity field and the phase-contrast MRI measurement data is fed back to the numerical simulation. The computational accuracy and the fundamental characteristics, such as steady characteristics and transient characteristics, of the MR-MI simulation were investigated by a numerical experiment. We dealt with reproduction of three-dimensional steady and unsteady blood flow fields in a realistic cerebral aneurysm developed at a bifurcation. The MR-MI simulation reduced the error derived from the incorrect boundary conditions in the blood flow in the cerebral aneurysm. For the reproduction of steady and unsteady standard solutions, the error of velocity decreased to 13% and to 22% in one cardiac cycle, respectively, compared with the ordinary simulation without feedback. Moreover, the application of feedback shortened the computational convergence, and thus the convergent solution and periodic solution were obtained within less computational time in the MR-MI simulation than that in the ordinary simulation. The dividing flow ratio toward the two outlets after bifurcation was well estimated owing to the improvement of computational accuracy. Furthermore, the MR-MI simulation yielded wall shear stress distribution on the cerebral aneurysm of the standard solution accurately and in detail. PMID:19350390

  8. Comparison of thermal clearance measurement of regional cerebral blood flow with radiolabelled microspheres

    SciTech Connect

    Hoehner, P.J.; Dean, J.M.; Rogers, M.C.; Traystman, R.J.

    1987-05-01

    A thermal clearance technique for measuring cerebral blood flow is described and compared with the radiolabelled microsphere technique. The thermal technique involves measurement of the rewarming curve generated after bolus infusion of 4-5 ml of ice-cold saline into the common carotid artery with a subdural thermistor placed on the parietal cortex. Evaluation of the biexponential decay curves obtained with this technique demonstrated a close correlation with total hemispheric, parietal, and parietal gray blood flow determined by simultaneous microsphere measurement. Despite significant correlations (p less than 0.001), scatter in the data produced a broad 95% confidence interval, thus making interpretation of blood flow with the thermal clearance technique impossible. Furthermore, instrumentation with the thermal probe, which required opening of the dura, blunted the cerebral blood flow response to hypercapnia. We conclude that the major limitations of the thermal clearance technique include: nonhomogeneous clearance function, significant variability, and depression of CO/sub 2/ reactivity. These limitations must be addressed before this technique can be used reliably in the laboratory.

  9. Remote effect of deep-seated vascular brain lesions on cerebral blood flow

    SciTech Connect

    Attig, E.; Capon, A.; Demeurisse, G.; Verhas, M. )

    1990-11-01

    We measured regional cerebral blood flow using the xenon-133 inhalation method, at approximately 1 month after onset, in 60 stroke patients who had no evidence of major carotid artery stenosis or occlusion. Their single lesions (43 infarcts and 17 hematomas) were located in the capsulothalamolenticular region, sparing the cortex. Hemispheric mean cerebral blood flow was reduced on the side of the lesion in 25 patients and on both sides in 20. Regional hypoperfusion was observed in 46 patients (ipsilaterally in 34, bilaterally in 10, and contralaterally in two). Regional hypoperfusion was observed most frequently in the frontal lobe, particularly in the motor and premotor cortices of the prerolandic area. The 46 patients with regional hypoperfusion were compared with the 14 patients without regional hypoperfusion, considering the size and location of the lesion as well as the functional and analytic motor performances. As a rule, the lesion was slightly smaller and more posterior and the functional (p less than 0.001) and analytic (p less than 0.05) motor performances were significantly better in the 14 patients without regional hypoperfusion. Since the xenon-133 inhalation method examines cortical blood flow, we can attribute blood flow reductions resulting from deep-seated lesions to a functional depression akin to diaschisis. Interpretation of the clinical consequences and pathogenesis of this phenomenon requires further sequential and pathologic studies.

  10. Reduced regional cerebral blood flow in Huntington's disease studied by SPECT.

    PubMed Central

    Hasselbalch, S G; Oberg, G; Sørensen, S A; Andersen, A R; Waldemar, G; Schmidt, J F; Fenger, K; Paulson, O B

    1992-01-01

    Regional cerebral blood flow (rCBF) was studied in 18 patients with Huntington's disease (HD) and 19 age- and sex-matched controls with high resolution single photon emission computerised tomography (SPECT), using Tc-99m-HMPAO. Significant reductions in tracer uptake were found in the caudate and lentiform nuclei (20 and 8%) and in the cerebral cortex, especially in the frontal and parietal areas (11-13%). No significant reductions were found in the thalamus, mesial temporal cortex, and occipital cortex. Fourteen patients had neuropsychological testing. Relationship between rCBF and cognitive function was tested by regression analysis. A linear relationship was found between test scores of Wisconsin Card Sorting Test, Picture Arrangement Test and blood flow in the caudate nucleus. Other tests of cognitive function (Block Design Test, Face and Word Recognition Test, Street Fragmented Pictures Test, and Similarities Test) correlated better with flow in the cortical regions believed to be involved in solving those particular tests. These findings indicate, that blood flow is reduced in both cortical and subcortical structures in symptomatic HD, and that both reductions in cortical and subcortical blood flow may be related to cognitive function in HD. Images PMID:1469396

  11. Functional photoacoustic tomography for non-invasive imaging of cerebral blood oxygenation and blood volume in rat brain in vivo

    NASA Astrophysics Data System (ADS)

    Wang, Xueding; Xie, Xueyi; Ku, Geng; Stoica, George; Wang, Lihong V.

    2005-04-01

    Based on the multi-wavelength laser-based photoacoustic tomography, non-invasive in vivo imaging of functional parameters, including the hemoglobin oxygen saturation and the total concentration of hemoglobin, in small-animal brains was realized. The high sensitivity of this technique is based on the spectroscopic differences between oxy- and deoxy-hemoglobin while its spatial resolution is bandwidth-limited by the photoacoustic signals rather than by the optical diffusion as in optical imaging. The point-by-point distributions of blood oxygenation and blood volume in the cerebral cortical venous vessels, altered by systemic physiological modulations including hyperoxia, normoxia and hypoxia, were visualized successfully through the intact skin and skull. This technique, with its prominent intrinsic advantages, can potentially accelerate the progress in neuroscience and provide important new insights into cerebrovascular physiology and brain function that are of great significance to the neuroscience community.

  12. Peripheral blood natural killer cells and mild thyroid abnormalities in women with reproductive failure.

    PubMed

    Triggianese, P; Perricone, C; Conigliaro, P; Chimenti, M S; Perricone, R; De Carolis, C

    2016-03-01

    Abnormalities in peripheral blood natural killer (NK) cells have been reported in women with primary infertility and recurrent spontaneous abortion (RSA) and several studies have been presented to define cutoff values for abnormal peripheral blood NK cell levels in this context. Elevated levels of NK cells were observed in infertile/RSA women in the presence of thyroid autoimmunity (TAI), while no studies have been carried out, to date, on NK cells in infertile/RSA women with non-autoimmune thyroid diseases. The contribution of this study is two-fold: (1) the evaluation of peripheral blood NK cell levels in a cohort of infertile/RSA women, in order to confirm related data from the literature; and (2) the assessment of NK cell levels in the presence of both TAI and subclinical hypothyroidism (SCH) in order to explore the possibility that the association between NK cells and thyroid function is not only restricted to TAI but also to SCH. In a retrospective study, 259 age-matched women (primary infertility [n = 49], primary RSA [n = 145], and secondary RSA [n = 65]) were evaluated for CD56+CD16+NK cells by flow cytometry. Women were stratified according to thyroid status: TAI, SCH, and without thyroid diseases (ET). Fertile women (n = 45) were used as controls. Infertile/RSA women showed higher mean NK cell levels than controls. The cutoff value determining the abnormal NK cell levels resulted ⩾15% in all the groups of women. Among the infertile/RSA women, SCH resulted the most frequently associated thyroid disorder while no difference resulted in the prevalence of TAI and ET women between patients and controls. A higher prevalence of women with NK cell levels ⩾15% was observed in infertile/RSA women with SCH when compared to TAI/ET women. According to our data, NK cell assessment could be used as a diagnostic tool in women with reproductive failure and we suggest that the possible association between NK cell levels and thyroid function can be described not only

  13. Sleep apnea termination decreases cerebral blood volume: a near-infrared spectroscopy case study

    NASA Astrophysics Data System (ADS)

    Virtanen, Jaakko; Noponen, Tommi; Salmi, Tapani; Toppila, Jussi; Meriläinen, Pekka

    2009-07-01

    Medical near-infrared spectroscopy (NIRS) can be used to estimate cerebral haemodynamic changes non-invasively. Sleep apnea is a common sleep disorder where repetitive pauses in breathing decrease the quality of sleep and exposes the individual to various health problems. We have measured oxygenated and deoxygenated haemoglobin concentration changes during apneic events in sleep from the forehead of one subject using NIRS and used principal component analysis to extract extracerebral and cortical haemodynamic changes from NIRS signals. Comparison of NIRS signals with EEG, bioimpedance, and pulse oximetry data suggests that termination of apnea leads to decreases in cerebral blood volume and flow that may be related to neurological arousal via neurovascular coupling.

  14. Cerebral venous blood oxygenation monitoring during hyperventilation in healthy volunteers with a novel optoacoustic system

    NASA Astrophysics Data System (ADS)

    Petrov, Andrey; Prough, Donald S.; Petrov, Irene Y.; Petrov, Yuriy; Deyo, Donald J.; Henkel, Sheryl N.; Seeton, Roger; Esenaliev, Rinat O.

    2013-03-01

    Monitoring of cerebral venous oxygenation is useful to facilitate management of patients with severe or moderate traumatic brain injury (TBI). Prompt recognition of low cerebral venous oxygenation is a key to avoiding secondary brain injury associated with brain hypoxia. In specialized clinical research centers, jugular venous bulb catheters have been used for cerebral venous oxygenation monitoring and have demonstrated that oxygen saturation < 50% (normal range is 55-75%) correlates with poor clinical outcome. We developed an optoacoustic technique for noninvasive monitoring of cerebral venous oxygenation. Recently, we designed and built a novel, medical grade optoacoustic system operating in the near-infrared spectral range for continuous, real-time oxygenation monitoring in the superior sagittal sinus (SSS), a large central cerebral vein. In this work, we designed and built a novel SSS optoacoustic probe and developed a new algorithm for SSS oxygenation measurement. The SSS signals were measured in healthy volunteers during voluntary hyperventilation, which induced changes in SSS oxygenation. Simultaneously, we measured exhaled carbon dioxide concentration (EtCO2) using capnography. Good temporal correlation between decreases in optoacoustically measured SSS oxygenation and decreases in EtCO2 was obtained. Decreases in EtCO2 from normal values (35-45 mmHg) to 20-25 mmHg resulted in SSS oxygenation decreases by 3-10%. Intersubject variability of the responses may relate to nonspecific brain activation associated with voluntary hyperventilation. The obtained data demonstrate the capability of the optoacoustic system to detect in real time minor changes in the SSS blood oxygenation.

  15. Depth discrimination in acousto-optic cerebral blood flow measurement simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Schiffer, Z.; Ratner, E.; Breskin, I.; Zeitak, R.; Shechter, R.; Balberg, M.

    2016-03-01

    Monitoring cerebral blood flow (CBF) is crucial, as inadequate perfusion, even for relatively short periods of time, may lead to brain damage or even death. Thus, significant research efforts are directed at developing reliable monitoring tools that will enable continuous, bed side, simple and cost-effective monitoring of CBF. All existing non invasive bed side monitoring methods, which are mostly NIRS based, such as Laser Doppler or DCS, tend to underestimate CBF in adults, due to the indefinite effect of extra-cerebral tissues on the obtained signal. If those are to find place in day to day clinical practice, the contribution of extra-cerebral tissues must be eliminated and data from the depth (brain) should be extracted and discriminated. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133Xe SPECT and laser Doppler. We have assembled a comprehensive computerized simulation, modeling this acousto-optic technique in a highly scattering media. Using the combination of light and ultrasound, we show how depth information may be extracted, thus distinguishing between flow patterns taking place at different depths. Our algorithm, based on the analysis of light modulated by ultrasound, is presented and examined in a computerized simulation. Distinct depth discrimination ability is presented, suggesting that using such method one can effectively nullify the extra-cerebral tissues influence on the obtained signals, and specifically extract cerebral flow data.

  16. Caffeine and human cerebral blood flow: A positron emission tomography study

    SciTech Connect

    Cameron, O.G.; Modell, J.G.; Hariharan, M. )

    1990-01-01

    Positron emission tomography (PET) was used to quantify the effect of caffeine on whole brain and regional cerebral blood flow (CBF) in humans. A mean dose of 250 mg of caffeine produced approximately a 30% decrease in whole brain CBF; regional differences in caffeine effect were not observed. Pre-caffeine CBF strongly influenced the magnitude of the caffeine-induced decrease. Caffeine decreased p{sub a}CO{sub 2} and increased systolic blood pressure significantly; the change in p{sub a}CO{sub 2} did not account for the change in CBF. Smaller increases in diastolic blood pressure, heart rate, plasma epinephrine and norepinephrine, and subjectively reported anxiety were also observed.

  17. Red blood cell transfusion increases cerebral oxygen delivery in anemic patients with subarachnoid hemorrhage

    PubMed Central

    Dhar, Rajat; Zazulia, Allyson R; Videen, Tom O; Zipfel, Gregory J; Derdeyn, Colin P; Diringer, Michael N

    2009-01-01

    Background Anemia is common after subarachnoid hemorrhage (SAH) and may exacerbate the reduction in oxygen delivery (DO2) underlying delayed cerebral ischemia (DCI). The association between lower hemoglobin and worse outcome, including more cerebral infarcts, supports a role for red blood cell (RBC) transfusion to correct anemia. However, the cerebral response to transfusion remains uncertain, as higher hemoglobin may increase viscosity and further impair cerebral blood flow (CBF) in the setting of vasospasm. Methods Eight patients with aneurysmal SAH and hemoglobin < 10 g/dl were studied with 15O-PET before and after transfusion of 1 unit of RBCs. Paired t-tests were used to analyze the change in global and regional CBF, oxygen extraction fraction (OEF), and oxygen metabolism (CMRO2) after transfusion. DO2 was calculated from CBF and arterial oxygen content (CaO2). CBF, CMRO2 and DO2 are reported in ml/100g/min. Results Transfusion resulted in a 15% rise in hemoglobin (8.7±0.8 to 10.0±1.0 g/dl) and CaO2 (11.8±1.0 to 13.6±1.1 ml/dL, both p < 0.001). Global CBF remained stable (40.5±8.1 to 41.6±9.9), resulting in an 18% rise in DO2 from 4.8±1.1 to 5.7±1.4 (p = 0.017). This was associated with a fall in OEF from 0.49±0.11 to 0.41±0.11 (p = 0.11) and stable CMRO2. Rise in DO2 was greater (28%) in regions with oligemia (low DO2 and OEF≥0.5) at baseline, but was attenuated (10%) within territories exhibiting angiographic vasospasm, where CBF fell 7%. Conclusions Transfusion of RBCs to anemic patients with SAH resulted in a significant rise in cerebral DO2 without lowering global CBF. This was associated with reduced OEF, which may improve tolerance of vulnerable brain regions to further impairments of CBF. Further studies are needed to confirm the benefit of transfusion on DCI and balance this against potential systemic and cerebral risks. PMID:19628806

  18. Abnormal White Matter Blood-Oxygen-Level-Dependent Signals in Chronic Mild Traumatic Brain Injury.

    PubMed

    Astafiev, Serguei V; Shulman, Gordon L; Metcalf, Nicholas V; Rengachary, Jennifer; MacDonald, Christine L; Harrington, Deborah L; Maruta, Jun; Shimony, Joshua S; Ghajar, Jamshid; Diwakar, Mithun; Huang, Ming-Xiong; Lee, Roland R; Corbetta, Maurizio

    2015-08-15

    Concussion, or mild traumatic brain injury (mTBI), can cause persistent behavioral symptoms and cognitive impairment, but it is unclear if this condition is associated with detectable structural or functional brain changes. At two sites, chronic mTBI human subjects with persistent post-concussive symptoms (three months to five years after injury) and age- and education-matched healthy human control subjects underwent extensive neuropsychological and visual tracking eye movement tests. At one site, patients and controls also performed the visual tracking tasks while blood-oxygen-level-dependent (BOLD) signals were measured with functional magnetic resonance imaging. Although neither neuropsychological nor visual tracking measures distinguished patients from controls at the level of individual subjects, abnormal BOLD signals were reliably detected in patients. The most consistent changes were localized in white matter regions: anterior internal capsule and superior longitudinal fasciculus. In contrast, BOLD signals were normal in cortical regions, such as the frontal eye field and intraparietal sulcus, that mediate oculomotor and attention functions necessary for visual tracking. The abnormal BOLD signals accurately differentiated chronic mTBI patients from healthy controls at the single-subject level, although they did not correlate with symptoms or neuropsychological performance. We conclude that subjects with persistent post-concussive symptoms can be identified years after their TBI using fMRI and an eye movement task despite showing normal structural MRI and DTI. PMID:25758167

  19. Regional Cerebral Blood Flow (rCBF) in Developmental Dyslexia: Activation during Reading in a Surface and Deep Dyslexic.

    ERIC Educational Resources Information Center

    Hynd, George W.; And Others

    1987-01-01

    The exploratory study examined patterns of regional cerebral blood flow in a surface and a deep dyslexic during reading. Significant differences in gray matter blood flow were found between subjects and normal controls. Also differences existed between the surface and deep dyslexic in the distribution of cortical perfusion. (Author/DB)

  20. Transient Aortic Occlusion Augments Collateral Blood Flow and Reduces Mortality During Severe Ischemia due to Proximal Middle Cerebral Artery Occlusion.

    PubMed

    Ramakrishnan, Gomathi; Dong, Bin; Todd, Kathryn G; Shuaib, Ashfaq; Winship, Ian R

    2016-04-01

    Cerebral collateral circulation provides alternative vascular routes for blood to reach ischemic tissues during stroke. Collateral therapeutics attempt to augment flow through these collateral channels to reduce ischemia and brain damage during acute ischemic stroke. Transient aortic occlusion (TAO) has pre-clinical data suggesting that it can augment collateral blood flow and clinical data suggesting a benefit for patients with moderate cortical strokes. By diverting blood from the periphery towards the cerebral circulation, TAO has the potential to augment primary collateral flow at the circle of Willis and thereby improve outcome even during large, hemispheric strokes. Using proximal middle and anterior cerebral artery occlusion in rats, we demonstrate that TAO reduces mortality and improves collateral blood flow in severely ischemic animals. As such, TAO may be an effective therapy to reduce early mortality during severe ischemia associated with proximal occlusions. PMID:26706246

  1. Time-resolved near-infrared technique for bedside monitoring of absolute cerebral blood flow

    NASA Astrophysics Data System (ADS)

    Diop, Mamadou; Tichauer, Kenneth M.; Elliott, Jonathan T.; Migueis, Mark; Lee, Ting-Yim; St. Lawrence, Keith

    2010-02-01

    A primary focus of neurointensive care is monitoring the injured brain to detect harmful events that can impair cerebral blood flow (CBF). Since current non-invasive bedside methods can only indirectly assess blood flow, the goal of this research was to develop an optical technique for measuring absolute CBF. A time-resolved near-infrared (NIR) apparatus was built and its ability to accurately measure changes in optical properties was demonstrated in tissue-mimicking phantoms. The time-resolved system was combined with a bolus-tracking method for measuring CBF using the dye indocyanine green (ICG) as an intravascular flow tracer. Cerebral blood flow was measured in newborn piglets and for comparison, CBF was concurrently measured using a previously developed continuous-wave NIR method. Measurements were acquired with both techniques under three conditions: normocapnia, hypercapnia and following occlusion of the carotid arteries. Mean CBF values (N = 3) acquired with the TR-NIR system were 31.9 +/- 11.7 ml/100g/min during occlusion, 39.7 +/- 1.6 ml/100g/min at normocapnia, and 58.8 +/- 9.9 ml/100g/min at hypercapnia. Results demonstrate that the developed TR-NIR technique has the sensitivity to measure changes in CBF; however, the CBF measurements were approximately 25% lower than the values obtained with the CW-NIRS technique.

  2. Developmental changes in regional cerebral blood flow in fetal and newborn lambs.

    PubMed

    Szymonowicz, W; Walker, A M; Cussen, L; Cannata, J; Yu, V Y

    1988-01-01

    Developmental changes in regional cerebral blood flow (CBF) were determined using radioactively labeled microspheres to measure flow to the cortex, brain stem, cerebellum, white matter, caudate nucleus, and choroid plexus in three groups of chronically catheterized lambs under physiological conditions: 90- to 100-day preterm fetal lambs (n = 14), 125- to 136-day near-term fetal lambs (n = 11), and newborn lambs 5-44 days old (n = 10). We continually monitored heart rate, central venous pressure, and mean arterial blood pressure (MAP) and periodically measured arterial blood O2 and CO2 tensions (PaO2, PaCO2, respectively), pH, hemoglobin, and oxygen saturation (SaO2). The regional CBF measurements (ml.100 g-1.min-1) revealed that in all three age groups the high flow areas are the choroid plexus and caudate nucleus, whereas the lowest flow area is the white matter. There is, however, a different hierarchy of regional CBF in utero (cortex less than cerebellum and brain stem) compared with extrauterine life in the newborn lamb (cortex and cerebellum greater than brain stem). Analysis of regional cerebral oxygen delivery [CBF times arterial oxygen content (CaO2)] demonstrated a progressively increasing oxygen transport to the cortex with increasing gestational maturity and after birth. Oxygen transport to the brain stem, cerebellum, and white matter increased with gestational age, but did not increase after birth. Relationships between regional CBF and natural physiological variations of cardiorespiratory parameters (PaO2, SaO2, CaO2, pH, PaCO2, and MAP) were assessed using regression analysis. Correlations of regional CBF with PaO2 and SaO2 suggest that cerebral perfusion is not primarily determined by CaO2 when variations occur within the physiological range.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3337259

  3. Predictors of cerebral blood flow in patients with and without anemia.

    PubMed

    Borzage, Matthew T; Bush, Adam M; Choi, Soyoung; Nederveen, Aart J; Václavů, Lena; Coates, Thomas D; Wood, John C

    2016-04-15

    Sickle cell disease (SCD) is the most common cause of stroke in childhood and results primarily from a mismatch of cerebral oxygen supply and demand rather than arterial obstruction. However, resting cerebral blood flow (CBF) has not been examined in the general African American population, in whom obesity, hypertension, cerebrovascular disease, and diminished cerebrovascular reserve capacity are common. To better understand the underlying physiological substrate upon which SCD is superimposed, we measured CBF in 32 young (age 28 ± 10 yr), asymptomatic African American subjects with and without sickle cell trait (n= 14). To characterize the effects of chronic anemia, in isolation of sickle hemoglobin we also studied a cohort of 13 subjects with thalassemia major (n= 10), dyserythropoetic anemia (n= 1), or spherocytosis (n= 2). Blood was analyzed for complete blood count, hemoglobin electrophoresis, cell free hemoglobin, and lactate dehydrogenase. Multivariate regression analysis showed that oxygen content was the strongest predictor of CBF (r(2)= 0.33,P< 0.001). CBF declined rapidly in the second and third decades of life, but this drop was explained by reductions in cerebral gray matter. However, age effects persisted after correction for brain composition, possibly representing microvascular impairment. CBF was independent of viscosity, hemoglobin S%, and body mass index. Hyperoxia resulted in reduced CBF by 12.6% (P= 0.0002), and CBF changes were proportional to baseline oxygen content (r(2)= 0.16,P= 0.02). These data suggest that these hemoglobin subtypes do not alter the normal CBF regulation of the balance of oxygen supply and demand. PMID:26796758

  4. Face cooling with mist water increases cerebral blood flow during exercise: effect of changes in facial skin blood flow.

    PubMed

    Miyazawa, Taiki; Horiuchi, Masahiro; Ichikawa, Daisuke; Subudhi, Andrew W; Sugawara, Jun; Ogoh, Shigehiko

    2012-01-01

    Facial cooling (FC) increases cerebral blood flow (CBF) at rest and during exercise; however, the mechanism of this response remains unclear. The purpose of the present study was to test our hypothesis that FC causes facial vasoconstriction that diverts skin blood flow (SkBF(face)) toward the middle cerebral artery (MCA V(mean)) at rest and to a greater extent during exercise. Nine healthy young subjects (20 ± 2 years) underwent 3 min of FC by fanning and spraying the face with a mist of cold water (~4°C) at rest and during steady-state exercise [heart rate (HR) of 120 bpm]. We focused on the difference between the averaged data acquired from 1 min immediately before FC and last 1 min of FC. SkBF(face), MCA V(mean), and mean arterial blood pressure (MAP) were higher during exercise than at rest. As hypothesized, FC decreased SkBF(face) at rest (-32 ± 4%) and to a greater extent during exercise (-64 ± 10%, P = 0.012). Although MCA V(mean) was increased by FC (Rest, +1.4 ± 0.5 cm/s; Exercise, +1.4 ± 0.6 cm/s), the amount of the FC-evoked changes in MCA V(mean) at rest and during exercise differed among subjects. In addition, changes in MCA V(mean) with FC did not correlate with concomitant changes in SkBF(face) (r = 0.095, P = 0.709). MAP was also increased by FC (Rest, +6.2 ± 1.4 mmHg; Exercise, +4.2 ± 1.2 mmHg). These findings suggest that the FC-induced increase in CBF during exercise could not be explained only by change in SkBF(face). PMID:22934059

  5. The locus coeruleus-norepinephrine network optimizes coupling of cerebral blood volume with oxygen demand.

    PubMed

    Bekar, Lane K; Wei, Helen S; Nedergaard, Maiken

    2012-12-01

    Given the brain's uniquely high cell density and tissue oxygen levels bordering on hypoxia, the ability to rapidly and precisely match blood flow to constantly changing patterns in neural activity is an essential feature of cerebrovascular regulation. Locus coeruleus-norepinephrine (LC-NE) projections innervate the cerebral vasculature and can mediate vasoconstriction. However, function of the LC-mediated constriction in blood-flow regulation has never been addressed. Here, using intrinsic optical imaging coupled with an anesthesia regimen that only minimally interferes with LC activity, we show that NE enhances spatial and temporal aspects of functional hyperemia in the mouse somatosensory cortex. Increasing NE levels in the cortex using an α(2)-adrenergic receptor antagonist paradoxically reduces the extent of functional hyperemia while enhancing the surround blood-flow reduction. However, the NE-mediated vasoconstriction optimizes spatial and temporal focusing of the hyperemic response resulting in a sixfold decrease in the disparity between blood volume and oxygen demand. In addition, NE-mediated vasoconstriction accelerated redistribution to subsequently active regions, enhancing temporal synchronization of blood delivery. These observations show an important role for NE in optimizing neurovascular coupling. As LC neuron loss is prominent in Alzheimer and Parkinson diseases, the diminished ability to couple blood volume to oxygen demand may contribute to their pathogenesis. PMID:22872230

  6. Regional cerebral blood flow for singers and nonsingers while speaking, singing, and humming a rote passage

    SciTech Connect

    Formby, C.; Thomas, R.G.; Halsey, J.H. Jr. )

    1989-05-01

    Two groups of singers (n = 12,13) and a group of nonsingers (n = 12) each produced the national anthem by (1) speaking and (2) singing the words and by (3) humming the melody. Regional cerebral blood flow (rCBF) was measured at rest and during each phonation task from seven areas in each hemisphere by the {sup 133}Xe-inhalation method. Intrahemisphere, interhemisphere, and global rCBF were generally similar across phonation tasks and did not yield appreciable differences among the nonsingers and the singers.

  7. Chronicity and a low anteroposterior gradient of cerebral blood flow in schizophrenia

    SciTech Connect

    Mathew, R.J.; Wilson, W.H. )

    1990-02-01

    Regional cerebral blood flow (CBF) was measured with the 133xenon inhalation technique in 27 patients with schizophrenia of less than 5 years' duration and in 27 patients with schizophrenia of more than 12 years' duration, under resting conditions. Similar measurements were also performed in 54 normal control subjects matched for age and sex. Patients with schizophrenia of long duration had lower anteroposterior gradients of CBF than patients with schizophrenia of short duration and matched control subjects. Covarying out age and end-tidal levels of CO2 did not alter the results.

  8. Regional cerebral blood flow for singers and nonsingers while speaking, singing, and humming a rote passage.

    PubMed

    Formby, C; Thomas, R G; Halsey, J H

    1989-05-01

    Two groups of singers (n = 12,13) and a group of nonsingers (n = 12) each produced the national anthem by (1) speaking and (2) singing the words and by (3) humming the melody. Regional cerebral blood flow (rCBF) was measured at rest and during each phonation task from seven areas in each hemisphere by the 133Xe-inhalation method. Intrahemisphere, interhemisphere, and global rCBF were generally similar across phonation tasks and did not yield appreciable differences among the nonsingers and the singers. PMID:2720376

  9. The effects of altered intrathoracic pressure on resting cerebral blood flow and its response to visual stimulation

    PubMed Central

    Hayen, Anja; Herigstad, Mari; Kelly, Michael; Okell, Thomas W.; Murphy, Kevin; Wise, Richard G.; Pattinson, Kyle T.S.

    2013-01-01

    Investigating how intrathoracic pressure changes affect cerebral blood flow (CBF) is important for a clear interpretation of neuroimaging data in patients with abnormal respiratory physiology, intensive care patients receiving mechanical ventilation and in research paradigms that manipulate intrathoracic pressure. Here, we investigated the effect of experimentally increased and decreased intrathoracic pressures upon CBF and the stimulus-evoked CBF response to visual stimulation. Twenty healthy volunteers received intermittent inspiratory and expiratory loads (plus or minus 9 cmH2O for 270 s) and viewed an intermittent 2 Hz flashing checkerboard, while maintaining stable end-tidal CO2. CBF was recorded with transcranial Doppler sonography (TCD) and whole-brain pseudo-continuous arterial spin labeling magnetic resonance imaging (PCASL MRI). Application of inspiratory loading (negative intrathoracic pressure) showed an increase in TCD-measured CBF of 4% and a PCASL-measured increase in grey matter CBF of 5%, but did not alter mean arterial pressure (MAP). Expiratory loading (positive intrathoracic pressure) did not alter CBF, while MAP increased by 3%. Neither loading condition altered the perfusion response to visual stimulation in the primary visual cortex. In both loading conditions localized CBF increases were observed in the somatosensory and motor cortices, and in the cerebellum. Altered intrathoracic pressures, whether induced experimentally, therapeutically or through a disease process, have possible significant effects on CBF and should be considered as a potential systematic confound in the interpretation of perfusion-based neuroimaging data. PMID:23108273

  10. Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes.

    PubMed

    Feddersen, Berend; Neupane, Pritam; Thanbichler, Florian; Hadolt, Irmgard; Sattelmeyer, Vera; Pfefferkorn, Thomas; Waanders, Robb; Noachtar, Soheyl; Ausserer, Harald

    2015-11-01

    Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3). Their EEG frontal beta activity and occipital alpha activity increased between 100 and 3,440 m altitude, i.e., before symptoms appeared. Cerebral blood flow velocity (CBFV) in the anterior and middle cerebral arteries (MCAs) increased in all mountaineers between 100 and 3,440 m altitude. During further ascent to 5,050 altitude, mountaineers with AMS developed a further increase in CBFV in the MCA, whereas in all mountaineers CBFV decreased continuously with increasing altitude in the posterior cerebral arteries. These results indicate that hypobaric hypoxia causes different regional changes in CBFV despite similar electrophysiological changes. PMID:26082017

  11. Lower stroke risk with lower blood pressure in hemodynamic cerebral ischemia

    PubMed Central

    Clarke, William R.; Grubb, Robert L.; Videen, Tom O.; Adams, Harold P.; Derdeyn, Colin P.

    2014-01-01

    Objective: To determine whether strict blood pressure (BP) control is the best medical management for patients with symptomatic carotid artery occlusion and hemodynamic cerebral ischemia. Methods: In this prospective observational cohort study, we analyzed data from 91 participants in the nonsurgical group of the Carotid Occlusion Surgery Study (COSS) who had recent symptomatic internal carotid artery occlusion and hemodynamic cerebral ischemia manifested by ipsilateral increased oxygen extraction fraction. The target BP goal in COSS was ≤130/85 mm Hg. We compared the occurrence of ipsilateral ischemic stroke during follow-up in the 41 participants with mean BP ≤130/85 mm Hg to the remaining 50 with higher BP. Results: Of 16 total ipsilateral ischemic strokes that occurred during follow-up, 3 occurred in the 41 participants with mean follow-up BP of ≤130/85 mm Hg, compared to 13 in the remaining 50 participants with mean follow-up BP >130/85 mm Hg (hazard ratio 3.742, 95% confidence interval 1.065–13.152, log-rank p = 0.027). Conclusion: BPs ≤130/85 mm Hg were associated with lower subsequent stroke risk in these patients. Classification of evidence: This study provides Class III evidence that control of hypertension ≤130/85 mm Hg is associated with a reduced risk of subsequent ipsilateral ischemic stroke in patients with recently symptomatic carotid occlusion and hemodynamic cerebral ischemia (increased oxygen extraction fraction). PMID:24532276

  12. Impaired cerebral cortex development and blood pressure regulation in FGF-2-deficient mice.

    PubMed

    Dono, R; Texido, G; Dussel, R; Ehmke, H; Zeller, R

    1998-08-01

    Fibroblast growth factor-2 (FGF-2) has been implicated in various signaling processes which control embryonic growth and differentiation, adult physiology and pathology. To analyze the in vivo functions of this signaling molecule, the FGF-2 gene was inactivated by homologous recombination in mouse embryonic stem cells. FGF-2-deficient mice are viable, but display cerebral cortex defects at birth. Bromodeoxyuridine pulse labeling of embryos showed that proliferation of neuronal progenitors is normal, whereas a fraction of them fail to colonize their target layers in the cerebral cortex. A corresponding reduction in parvalbumin-positive neurons is observed in adult cortical layers. Neuronal defects are not limited to the cerebral cortex, as ectopic parvalbumin-positive neurons are present in the hippocampal commissure and neuronal deficiencies are observed in the cervical spinal cord. Physiological studies showed that FGF-2-deficient adult mice are hypotensive. They respond normally to angiotensin II-induced hypertension, whereas neural regulation of blood pressure by the baroreceptor reflex is impaired. The present genetic study establishes that FGF-2 participates in controlling fates, migration and differentiation of neuronal cells, whereas it is not essential for their proliferation. The observed autonomic dysfunction in FGF-2-deficient adult mice uncovers more general roles in neural development and function. PMID:9687490

  13. Impaired cerebral cortex development and blood pressure regulation in FGF-2-deficient mice.

    PubMed Central

    Dono, R; Texido, G; Dussel, R; Ehmke, H; Zeller, R

    1998-01-01

    Fibroblast growth factor-2 (FGF-2) has been implicated in various signaling processes which control embryonic growth and differentiation, adult physiology and pathology. To analyze the in vivo functions of this signaling molecule, the FGF-2 gene was inactivated by homologous recombination in mouse embryonic stem cells. FGF-2-deficient mice are viable, but display cerebral cortex defects at birth. Bromodeoxyuridine pulse labeling of embryos showed that proliferation of neuronal progenitors is normal, whereas a fraction of them fail to colonize their target layers in the cerebral cortex. A corresponding reduction in parvalbumin-positive neurons is observed in adult cortical layers. Neuronal defects are not limited to the cerebral cortex, as ectopic parvalbumin-positive neurons are present in the hippocampal commissure and neuronal deficiencies are observed in the cervical spinal cord. Physiological studies showed that FGF-2-deficient adult mice are hypotensive. They respond normally to angiotensin II-induced hypertension, whereas neural regulation of blood pressure by the baroreceptor reflex is impaired. The present genetic study establishes that FGF-2 participates in controlling fates, migration and differentiation of neuronal cells, whereas it is not essential for their proliferation. The observed autonomic dysfunction in FGF-2-deficient adult mice uncovers more general roles in neural development and function. PMID:9687490

  14. Influence of muscle metaboreceptor stimulation on middle cerebral artery blood velocity in humans.

    PubMed

    Braz, Igor D; Scott, Clare; Simpson, Lydia L; Springham, Emma L; Tan, Beverly W L; Balanos, George M; Fisher, James P

    2014-11-01

    Regional anaesthesia to attenuate skeletal muscle afferent feedback abolishes the exercise-induced increase in middle cerebral artery mean blood velocity (MCA Vmean). However, such exercise-related increases in cerebral perfusion are not preserved during post exercise muscle ischaemia (PEMI) where the activation of metabolically sensitive muscle afferents is isolated. We tested the hypothesis that a hyperventilation-mediated decrease in the arterial partial pressure of CO2, hence cerebral vasoconstriction, masks the influence of muscle metaboreceptor stimulation on MCA Vmean during PEMI. Ten healthy men (20 ± 1 years old) performed two trials of fatiguing isometric hand-grip exercise followed by PEMI, in control conditions and with end-tidal CO2 (P ET ,CO2) clamped at ∼1 mmHg above the resting partial pressure. In the control trial, P ET ,CO2 decreased from rest during hand-grip exercise and PEMI, while MCA Vmean was unchanged from rest. By design, P ET ,CO2 remained unchanged from rest throughout the clamp trial, while MCA Vmean increased during hand-grip (+10.6 ±1.8 cm s(-1)) and PEMI (+9.2 ± 1.6 cm s(-1); P < 0.05 versus rest and control trial). Increases in minute ventilation and mean arterial pressure during hand-grip and PEMI were not different in the control and P ET ,CO2 clamp trials (P > 0.05). These findings indicate that metabolically sensitive skeletal muscle afferents play an important role in the regional increase in cerebral perfusion observed in exercise, but that influence can be masked by a decrease in P ET ,CO2 when they are activated in isolation during PEMI. PMID:25217497

  15. Spontaneous fluctuations in cerebral blood flow: insights from extended-duration recordings in humans

    NASA Technical Reports Server (NTRS)

    Zhang, R.; Zuckerman, J. H.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

    2000-01-01

    To determine the dependence of cerebral blood flow (CBF) on arterial pressure over prolonged time periods, we measured beat-to-beat changes in mean CBF velocity in the middle cerebral artery (transcranial Doppler) and mean arterial pressure (Finapres) continuously for 2 h in six healthy subjects (5 men and 1 woman, 18-40 yr old) during supine rest. Fluctuations in velocity and pressure were quantified by the range [(peak - trough)/mean] and coefficients of variation (SD/mean) in the time domain and by spectral analysis in the frequency domain. Mean velocity and pressure over the 2-h recordings were 60 +/- 7 cm/s and 83 +/- 8 mmHg, associated with ranges of 77 +/- 8 and 89 +/- 10% and coefficients of variation of 9.3 +/- 2.2 and 7.9 +/- 2.3%, respectively. Spectral power of the velocity and pressure was predominantly distributed in the frequency range of 0.00014-0.1 Hz and increased inversely with frequency, indicating characteristics of an inverse power law (1/f(alpha)). However, linear regression on a log-log scale revealed that the slope of spectral power of pressure and velocity was steeper in the high-frequency (0.02-0.5 Hz) than in the low-frequency range (0.002-0.02 Hz), suggesting different regulatory mechanisms in these two frequency ranges. Furthermore, the spectral slope of pressure was significantly steeper than that of velocity in the low-frequency range, consistent with the low transfer function gain and low coherence estimated at these frequencies. We conclude that 1) long-term fluctuations in CBF velocity are prominent and similar to those observed in arterial pressure, 2) spectral power of CBF velocity reveals characteristics of 1/f(alpha), and 3) cerebral attenuation of oscillations in CBF velocity in response to changes in pressure may be more effective at low than that at high frequencies, emphasizing the frequency dependence of cerebral autoregulation.

  16. Cerebral blood flow, arteriovenous oxygen difference, and outcome in head injured patients.

    PubMed Central

    Robertson, C S; Contant, C F; Gokaslan, Z L; Narayan, R K; Grossman, R G

    1992-01-01

    Cerebral blood flow (CBF) and other physiological variables were measured repeatedly for up to 10 days after severe head injury in 102 patients, and CBF levels were related to outcome. Twenty five of the patients had a reduced CBF [mean (SD) 0.29 (0.05) ml/g/min]; 47 had a normal CBF, (0.41 (0.10) ml/g/min); and 30 had a raised CBF (0.62 (0.14) ml/g/min). Cerebral arteriovenous oxygen differences were inversely related to CBF and averaged 2.1 (0.7) mumol/ml in the group with reduced CBF, 1.9 (0.5) mumol/ml in the group with normal CBF, and 1.6 (0.4) mumol/ml in the group with raised CBF. Patients with a reduced CBF had a poorer outcome than patients with a normal or raised CBF. Mortality was highest in patients with a reduced CBF, and was 32% at three months after injury, whereas only 21% of the patients with a normal CBF and 20% of the patients with a raised CBF died. There were no differences in the type of injury, initial score on the Glasgow Coma Scale, mean intracranial pressure (ICP), highest ICP, or the amount of medical treatment required to keep the ICP less than 20 mm Hg in each group. Systemic factors did not significantly contribute to the differences in CBF among the three groups. A logistic regression model of the effect of CBF on neurological outcome was developed. When adjusted for variables which were found to be significant confounders, including age, initial Glasgow Coma Score, haemoglobin concentration, cerebral perfusion pressure and cerebral metabolic rate of oxygen, a reduced CBF remained significantly associated with an unfavourable neurological outcome. PMID:1640238

  17. Regional cerebral blood flow after hemorrhagic hypotension in the preterm, near-term, and newborn lamb.

    PubMed

    Szymonowicz, W; Walker, A M; Yu, V Y; Stewart, M L; Cannata, J; Cussen, L

    1990-10-01

    Developmental changes in regional cerebral blood flow (CBF) responses to hemorrhagic hypotension during normoxia and normocapnia were determined using radioactively labeled microspheres to measure flow to the cortex, brainstem, cerebellum, white matter, caudate nucleus, and choroid plexus in three groups of chronically catheterized lambs: 90- to 100-d preterm fetal lambs (n = 9); 125- to 136-d near-term fetal lambs (n = 9); and newborn lambs 5- to 35-d-old (n = 8). Heart rate, central venous pressure, and arterial blood pressure were monitored continuously and arterial blood gas tensions, pH, Hb, and oxygen saturation together with regional CBF were measured periodically. Hemorrhagic hypotension produced a mean decrease in arterial blood pressure of 27 +/- 4, 23 +/- 2, and 41 +/- 4% in the three groups, respectively, whereas reinfusion of the lamb's blood resulted in a return to control blood pressure within 3% in all three groups. In the pre-term fetal lamb, CBF decreased significantly in all regions during hypotension. In the near-term fetal lamb, only blood flow to the cortex decreased significantly during hypotension. In the newborn lamb, only the choroid plexus demonstrated a significant decrease in blood flow during hypotension. The lower limit of regional CBF autoregulation was identical to the resting mean arterial pressure in fetal life but significantly lower in newborn lambs. These experiments demonstrate for the first time that vulnerability to hypotension decreases with increasing maturity and that the brainstem, the phylogenetically oldest region of the brain, is the least vulnerable to the effects of hypotension at any age in the lamb model. PMID:2235134

  18. Measurement of Absolute Arterial Cerebral Blood Volume in Human Brain Without Using a Contrast Agent

    PubMed Central

    Hua, Jun; Qin, Qin; Pekar, James J.; van Zijl, Peter C. M.

    2011-01-01

    Arterial cerebral blood volume (CBVa) is a vital indicator of tissue perfusion and vascular reactivity. We extended the recently developed inflow vascular-space-occupancy (iVASO) MRI technique, which uses spatially selective inversion to suppress the signal from blood flowing into a slice, with a control scan to measure absolute CBVa using CSF for signal normalization. Images were acquired at multiple blood nulling times to account for the heterogeneity of arterial transit times across the brain, from which both CBVa and arterial transit times were quantified. Arteriolar CBVa was determined separately by incorporating velocity-dependent bipolar crusher gradients. Gray matter CBVa values (n = 11) were 2.04 ± 0.27 and 0.76 ± 0.17 ml blood/100 ml tissue without and with crusher gradients (b = 1.8 s/mm2), respectively. Arterial transit times were 671 ± 43 and 785 ± 69 ms, respectively. The arterial origin of the signal was validated by measuring its T2, which was within arterial range. The proposed approach does not require exogenous contrast agent administration, and provides a noninvasive alternative to existing blood volume techniques for mapping absolute CBVa in studies of brain physiology and neurovascular diseases. PMID:21608057

  19. Multicompartmental analysis of tracer clearance and its application to cerebral blood flow measurement

    SciTech Connect

    Rusinek, H.

    1986-10-01

    A new algorithm for computing cerebral blood flow is shown to overcome compartmental slippage and unstability problems associated with the conventional bicompartmental analysis. The tracer clearance curve is decomposed into a nonnegative linear combination of predetermined flow components. A weighted average of flows above (below) a fixed threshold yields the gray (white) matter flow. The accuracy and the stability of the new algorithm are analyzed by Monte-Carlo simulations, determining the effect of factors such as random error in tracer concentration, gray-white flow difference, tissue content of gray matter, and end-fit time. While the new algorithm requires 50-100% more CPU time and memory space than the bicompartmental method, its accuracy and stability is superior, especially as the conditions of the measurement deteriorate. The results suggest that more than twofold error reduction in measuring the blood flow in pathological brain tissue is possible.

  20. Cerebral blood flow and brain atrophy correlated by xenon contrast CT scanning

    SciTech Connect

    Kitagawa, Y.; Meyer, J.S.; Tanahashi, N.; Rogers, R.L.; Tachibana, H.; Kandula, P.; Dowell, R.E.; Mortel, K.F.

    1985-11-01

    Correlations between cerebral blood flow (CBF) measured during stable xenon contrast CT scanning and standard CT indices of brain atrophy were investigated in the patients with senile dementia of Alzheimer type, multi-infarct dementia and idiopathic Parkinson's disease. Compared to age-matched normal volunteers, significant correlations were found in patients with idiopathic Parkinson's disease between cortical and subcortical gray matter blood flow and brain atrophy estimated by the ventricular body ratio, and mild to moderate brain atrophy were correlated with stepwise CBF reductions. However, in patients with senile dementia of Alzheimer type and multi-infarct dementia, brain atrophy was not associated with stepwise CBF reductions. Overall correlations between brain atrophy and reduced CBF were weak. Mild degrees of brain atrophy are not always associated with reduced CBF.

  1. Cerebral blood flow studied by Xenon-133 inhalation technique in parkinsonism: loss of hyperfrontal pattern

    SciTech Connect

    Bes, A.; Gueell, A.; Fabre, N.; Dupui, P.; Victor, G.; Geraud, G.

    1983-03-01

    Cerebral blood flow (grey matter flow) in parkinsonism requires further investigation. The noninvasive method of /sup 133/Xe inhalation permits study of larger numbers of subjects than previously used invasive techniques such as the intracarotid /sup 133/Xe injection method. Measurements were made in this laboratory in 30 subjects having Parkinson's disease. Mean hemispheric blood flow (F1) values were 70.4 +/- 9.3 ml/100 g/min, compared to 76.3 for a group of age-matched normal subjects, which is a decrease of -7.8%. The most striking difference was the loss of the hyperfrontal distribution in parkinsonism. The prefrontal F1 values were only 1.8% greater than the hemisphere grey matter flow, compared with 8.5% in controls of a similar age group.

  2. Cerebral blood flow studied by /sup 133/Xe inhalation technique in parkinsonism: loss of hyperfrontal pattern

    SciTech Connect

    Bes, A.; Gueell, A.; Fabre, N.; Dupui, P.; Victor, G.; Geraud, G.

    1983-03-01

    Cerebral blood flow (grey matter flow) in parkinsonism requires further investigation. The noninvasive method of /sup 133/Xe inhalation permits study of larger numbers of subjects than previously used invasive techniques such as the intracarotid /sup 133/Xe injection method. Measurements were made in this laboratory in 30 subjects having Parkinson's disease. Mean hemispheric blood flow (F1) values were 70.4 +/- 9.3 ml/100 g/min, compared to 76.3 for a group of age-matched normal subjects, which is a decrease of -7.8%. The most striking difference was the loss of the hyperfrontal distribution in parkinsonism. The prefrontal F1 values were only 1.8% greater than the hemisphere grey matter flow, compared with 8.5% in controls of a similar age group.

  3. Cerebral blood flow regulation, exercise and pregnancy: why should we care?

    PubMed

    Bisson, Michèle; Marc, Isabelle; Brassard, Patrice

    2016-05-01

    Cerebral blood flow (CBF) regulation is an indicator of cerebrovascular health increasingly recognized as being influenced by physical activity. Although regular exercise is recommended during healthy pregnancy, the effects of exercise on CBF regulation during this critical period of important blood flow increase and redistribution remain incompletely understood. Moreover, only a few studies have evaluated the effects of human pregnancy on CBF regulation. The present work summarizes current knowledge on CBF regulation in humans at rest and during aerobic exercise in relation to healthy pregnancy. Important gaps in the literature are highlighted, emphasizing the need to conduct well-designed studies assessing cerebrovascular function before, during and after this crucial life period to evaluate the potential cerebrovascular risks and benefits of exercise during pregnancy. PMID:26993053

  4. Imaging of cerebral blood flow-to-volume distribution using SPECT

    SciTech Connect

    Knapp, W.H.; von Kummer, R.; Kuebler, W.

    1986-04-01

    The ratio between cerebral blood flow (CBF) and cerebral blood volume (CBV) has been proposed as an adequate parameter for the evaluation of cerebrovascular disease (CVD), but to date it has not been assessed with SPECT. We have chosen (/sup 123/I)IMP for CBF and (/sup 99m/Tc) erythrocytes for CBV imaging. The distribution of both nuclides was investigated in succession using corrections for the contamination of the /sup 99m/Tc tomograms by /sup 123/I. The ratio between /sup 123/I and /sup 99m/Tc tomograms yielded the CBF/CBV distribution. Quantitation was obtained by side-to-side comparison of both hemispheres and of segments containing the territories affected by CVD. In 16 patients with CVD, CBF of the affected territories was 85 +/- 19% (s.d.) when related to the nonsymptomatic contralateral side (100%). When the regions of interest defined within one slice encompassed the entire affected hemisphere, the average CBF was 95 +/- 9%, again related to the nonsymptomatic side. The corresponding CBF/CBV data in 15 of these 16 patients were 60 +/- 32% and 81 +/- 16%. In unilateral internal carotid artery stenoses greater than 50% (N = 10), segmental CBF averaged 81.1 +/- 10.1% and CBF/CBV 49.6 +/- 15.5% relative to the contralateral side. The figures for the hemispheres were 92.8 +/- 5.8 and 75.8 +/- 12.6, respectively. These clinical findings mirror the characteristics of CBF autoregulation, namely the vasodilation of small vessels in decreased arterial perfusion pressure. They, therefore, substantiate SPECT imaging of CBF/CBV for the assessment of cerebral perfusion reserve in CVD.

  5. Hyperventilation-induced reduction in cerebral blood flow: Assessment by positron emission tomography

    SciTech Connect

    Bednarczyk, E.M.; Rutherford, W.F.; Leisure, G.P.; Munger, M.A.; Panacek, E.A.; Miraldi, F.D.; Green, J.A. )

    1990-05-01

    The use of positron emission tomography (PET) has been well documented as a relatively noninvasive method of measuring cerebral blood flow (CBF), both globally and regionally. The utility of readily detecting alterations in CBF is apparent, particularly when applied to the evaluation of therapeutic interventions thought to influence CBF. We report the effects of hypocapnia, an experimental condition of known cerebral vasoconstriction, in ten normal volunteers. Subjects had brain blood flow evaluated utilizing H215O as the positron emitter before and after approximately five minutes of hyperventilation. Baseline CBF was measured as a mean +/- SD of 61.2 +/- 16.3 mL/min/100 g of tissue. Mean baseline arterial blood gas values were PaO2 107.4 +/- 14 mm Hg, PaCO2 37.7 +/- 0.89 mm Hg, and pH 7.39 (calculated from mean (H+)). Post hyperventilation, global CBF was measured as 31.1 +/- 10.8 mL/min/100 g. Mean arterial blood gas values were PaO2 141.7 +/- 21 mm Hg, PaCO2 19.7 +/- 5 mm Hg, and pH 7.63 (calculated from mean (H+)). CBF decreased by a mean of 49.5 +/- 11 percent. Data analysis using the Student's t-test showed a significant change over baseline in PaCO2 (p less than 0.001) and CBF (p less than 0.001), in the hyperventilated state. Correlations were noted between the decrease in CBF and change in PaCO2 (r = 0.81) as well as between hyperventilation PaCO2 and the change in CBF (r = 0.97). We conclude that, as measured by PET, CBF decreases significantly during a state of artificial hyperventilation to a degree consistent with results seen using other methods. PET appears to be a valuable tool in the assessment of interventions that could influence CBF.

  6. Reduction in Cerebral Oxygenation After Prolonged Exercise in Hypoxia is Related to Changes in Blood Pressure.

    PubMed

    Horiuchi, Masahiro; Dobashi, Shohei; Kiuchi, Masataka; Endo, Junko; Koyama, Katsuhiro; Subudhi, Andrew W

    2016-01-01

    We investigated the relation between blood pressure and cerebral oxygenation (COX) immediately after exercise in ten healthy males. Subjects completed an exercise and recovery protocol while breathing either 21% (normoxia) or 14.1% (hypoxia) O2 in a randomized order. Each exercise session included four sets of cycling (30 min/set, 15 min rest) at 50% of altitude-adjusted peak oxygen uptake, followed by 60 min of recovery. After exercise, mean arterial pressure (MAP; 87±1 vs. 84±1 mmHg, average values across the recovery period) and COX (68±1% vs. 58±1%) were lower in hypoxia compared to normoxia (P<0.001). Changes in MAP and COX were correlated during the recovery period in hypoxia (r=0.568, P<0.001) but not during normoxia (r=0.028, not significant). These results demonstrate that reductions in blood pressure following exercise in hypoxia are (1) more pronounced than in normoxia, and (2) associated with reductions in COX. Together, these results suggest an impairment in cerebral autoregulation as COX followed changes in MAP more passively in hypoxia than in normoxia. These findings could help explain the increased risk for postexercise syncope at high altitude. PMID:26782200

  7. Photoperiodic Regulation of Cerebral Blood Flow in White-Footed Mice (Peromyscus leucopus).

    PubMed

    Borniger, Jeremy C; Teplitsky, Seth; Gnyawali, Surya; Nelson, Randy J; Rink, Cameron

    2016-01-01

    Individuals living outside the tropics need to adjust their behavioral and physiological repertoires throughout the year to adapt to the changing seasons. White-footed mice (Peromyscus leucopus) reduce hippocampal volumes, hippocampal-dependent memory function, long-term potentiation, and alter neurogenesis in response to short (winter-like) day lengths (photoperiods). During winter, these mice putatively shunt energy away from the brain to maximize peripheral thermogenesis, immune function, and survival. We hypothesized that these changes in brain function are accompanied by alterations in brain vasculature. We maintained white-footed mice in short (8 h light/16 h dark) or long (16 h light/8 h dark) photoperiods for 8-9 weeks. Mice were then perfused with fluorescein isothiocyanate (FITC)-conjugated tomato (Lycopersicon esculentum) lectin to visualize the perfused cerebrovasculature. Short-day mice reduced hippocampal and cortical capillary density (FITC(+) area); vessels isolated from short day-exposed mice expressed higher mRNA levels of the gelatinase matrix metalloproteinase 2 (MMP2). Additionally, short-day mice reduced cerebral blood flow ∼15% compared with their long-day counterparts, as assessed by laser speckle flowmetry. Immunohistochemistry revealed higher levels of MMP2 in the hippocampus of mice maintained in short days compared with long days, potentially contributing to the observed vascular remodeling. These data demonstrate that a discrete environmental signal (i.e., day length) can substantially alter cerebral blood flow in adult mammals. PMID:27570829

  8. A neutral lipophilic technetium-99m complex for regional cerebral blood flow imaging

    SciTech Connect

    Narra, R.K.; Nunn, A.D.; Kuczynski, B.L.; DiRocco, R.J.; Feld, T.; Silva, D.A.; Eckelman, W.C. )

    1990-08-01

    Technetium-99m-DMG-2MP (Chloro(bis(2,3-butanedionedioxime(1-)-0)(2,3- butanedionedioximato (2-)-N,N{prime},N{double prime},N{prime}{double prime},N{double prime}{double prime},N{prime}{double prime}{double prime}) (2-methylpropyl borato (2-))technetium)), also known as SQ 32097 is a member of a family of neutral lipophilic compounds generally known as boronic acid adducts of technetium dioxime complexes (BATOs). After i.v. administration, the concentration of ({sup 99m}Tc)DMG-2MP in various regions of the brain appears to be proportional to blood flow. In rats, 1.1% ID was in the brain at 5 min postinjection when the blood contained less than 3% ID. Over 24 hr excretion was 59% in the feces and 23% in the urine. The activity in monkey brain at 5 min was 2.8% ID and it cleared with a t1/2 of 86 min. Autoradiographs of monkey brain sections showed excellent regional detail with a gray/white ratio of 3.6 at 10 min. The distribution of ({sup 99m}Tc)DMG-2MP in the monkey brain corresponds to the known cytoarchitectural pattern of cerebral glucose metabolism. The properties of ({sup 99m}Tc)DMG-2MP make it a potentially useful agent for cerebral perfusion imaging in man.

  9. Effect of Premature Ventricular Contractions on Middle Cerebral Artery Blood Flow Velocity.

    PubMed

    Ameriso, S F; Fisher, M; Sager, P

    1991-08-01

    The effect of premature ventricular contractions on blood flow velocity in the middle cerebral artery was studied by transcranial Doppler ultrasonography in 1 0 patients. Velocity during three ectopic beats for each patient was lower than that during the preceding and the following beat in every recording. The decrease in peak velocity was 30.7 ± 12.4% and 37.1 ± 13.3% (mean ± standard deviation) compared to the preceding and following beat, respectively. This variation was significantly larger (p < 0.0001) than the spontaneous change observed during sinus rhythm, 2. 7 ± 2.2% in patients with premature ventricular contractions and 3.5 ± 3.2% in control subjects. Similar results were obtained for both mean and diastolic blood flow velocities. Systolic-diastolic ratios were similar for premature ventricular contractions, beats preceding or following premature ventricular contractions, and sinus rhythm beats. Transcranial Doppler ultrasound appears to be an excellent technique for analyzing the effects of cardiac arrhythmias on the cerebral circulation. PMID:27311107

  10. Effects of diving and oxygen on autonomic nervous system and cerebral blood flow.

    PubMed

    Winklewski, Pawel J; Kot, Jacek; Frydrychowski, Andrzej F; Nuckowska, Magdalena K; Tkachenko, Yurii

    2013-09-01

    Recreational scuba diving is a popular leisure activity with the number of divers reaching several millions worldwide. Scuba diving represents a huge challenge for integrative physiology. In mammalian evolution, physiological reflexes developed to deal with lack of oxygen, rather than with an excess, which makes adaptations to scuba diving more difficult to describe and understand than those associated with breath-hold diving. The underwater environment significantly limits the use of equipment to register the organism's functions, so, in most instances, scientific theories are built on experiments that model real diving to some extent, like hyperbaric exposures, dive reflexes or water immersion. The aim of this review is to summarise the current knowledge related to the influence exerted by physiological conditions specific to diving on the autonomic nervous system and cerebral blood flow. The main factors regulating cerebral blood flow during scuba diving are discussed as follows: 1) increased oxygen partial pressure; 2) immersion-related trigemino-cardiac reflexes and 3) exposure to cold, exercise and stress. Also discussed are the potential mechanisms associated with immersion pulmonary oedema. PMID:24122190

  11. Developmental trajectories of cerebral blood flow and oxidative metabolism at baseline and during working memory tasks.

    PubMed

    Jog, Mayank A; Yan, Lirong; Kilroy, Emily; Krasileva, Kate; Jann, Kay; LeClair, Holly; Elashoff, David; Wang, Danny J J

    2016-07-01

    The neurobiological interpretation of developmental BOLD fMRI findings remains difficult due to the confounding issues of potentially varied baseline of brain function and varied strength of neurovascular coupling across age groups. The central theme of the present research is to study the development of brain function and neuronal activity through in vivo assessments of cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) both at baseline and during the performance of a working memory task in a cohort of typically developing children aged 7 to 18years. Using a suite of 4 emerging MRI technologies including MR blood oximetry, phase-contrast MRI, pseudo-continuous arterial spin labeling (pCASL) perfusion MRI and concurrent CBF/BOLD fMRI, we found: 1) At baseline, both global CBF and CMRO2 showed an age related decline while global OEF was stable across the age group; 2) During the working memory task, neither BOLD nor CBF responses showed significant variations with age in the activated fronto-parietal brain regions. Nevertheless, detailed voxel-wise analyses revealed sub-regions within the activated fronto-parietal regions that show significant decline of fractional CMRO2 responses with age. These findings suggest that the brain may become more "energy efficient" with age during development. PMID:27103136

  12. Metabolomic analysis of clinical plasma from cerebral infarction patients presenting with blood stasis.

    PubMed

    Cha, Min Ho; Kim, Min Jung; Jung, Jeeyoun; Kim, Jin Hee; Lee, Myeong Soo; Kim, Myung-Sunny

    2015-01-01

    Blood stasis (BS) is characterized as a disorder of blood circulation. In traditional Korean medicine (TKM), it is viewed as a cause factor of diseases such as multiple sclerosis and stroke. This study investigated differences in the plasma metabolites profiles of subjects displaying BS or non-BS patterns. Thirty-one patients with cerebral infarction diagnosed with BS and an equal number of sex- and age-matched non-BS patients were enrolled. Metabolic profiling was performed using UPLC-MS. The ratio of subjects with a rough pulse and purple coloration of the tongue was higher in patients presenting with BS pattern. Through metabolomics analysis, 82 metabolites that differed significantly between the BS and non-BS pattern were identified, and the two groups were significantly separated using an orthogonal partial least square-discriminant analysis model (P < 0.001). Of these 82 metabolites, acetyl carnitine, leucine, kynurenine, phosphocholine, hexanoyl carnitine, and decanoyl carnitine were present in significantly higher levels in patients with a BS pattern than those with a non-BS pattern. Our results also demonstrated that seven plasma metabolites, including acyl-carnitines and kynurenine, were associated with a BS pattern, suggesting that variant plasma metabolic profiles may serve as a biomarker for diagnosis of BS in patients with cerebral infarction. PMID:25834622

  13. Effect of naloxone on regional cerebral blood flow during endotoxin shock in conscious rats

    SciTech Connect

    Law, W.R.; Ferguson, J.L. )

    1987-09-01

    Maintenance of cerebral blood flow (CBF) is vital during cardiovascular shock. Since opioids have been implicated in the pathophysiology of endotoxin shock and have been shown to alter cerebral perfusion patterns, the authors determined whether opioids were responsible for any of the changes in regional CBF observed during endotoxin shock and whether the use of naloxone might impair or aid in the maintenance of CBF. When blood flow (BF) is studied with radioactively-labeled microspheres in rats, the left ventricle of the heart is often cannulated via the right carotid artery. Questions have arisen concerning the potential adverse effects of this method on CBF in the hemisphere ipsilateral to the ligated artery. They measured right and left regional CBF by use of this route of cannulation. Twenty-four hours after cannulations were performed, flow measurements were made using radiolabeled microspheres in conscious unrestrained male Sprague-Dawley rats (300-400 g) before and 10, 30, and 60 min after challenging with 10 mg/kg Escherichia coli endotoxin (etx) or saline. Naloxone (2 mg/kg) or saline was given as a treatment 25 min post-etx. They found no significant differences between right and left cortical, midbrain, or cerebellar BF at any time in any treatment group. Therefore naloxone treatment of endotoxin shock may be beneficial in preventing decreases in regional CBF.

  14. Skin cooling maintains cerebral blood flow velocity and orthostatic tolerance during tilting in heated humans

    NASA Technical Reports Server (NTRS)

    Wilson, Thad E.; Cui, Jian; Zhang, Rong; Witkowski, Sarah; Crandall, Craig G.

    2002-01-01

    Orthostatic tolerance is reduced in the heat-stressed human. The purpose of this project was to identify whether skin-surface cooling improves orthostatic tolerance. Nine subjects were exposed to 10 min of 60 degrees head-up tilting in each of four conditions: normothermia (NT-tilt), heat stress (HT-tilt), normothermia plus skin-surface cooling 1 min before and throughout tilting (NT-tilt(cool)), and heat stress plus skin-surface cooling 1 min before and throughout tilting (HT-tilt(cool)). Heating and cooling were accomplished by perfusing 46 and 15 degrees C water, respectively, though a tube-lined suit worn by each subject. During HT-tilt, four of nine subjects developed presyncopal symptoms resulting in the termination of the tilt test. In contrast, no subject experienced presyncopal symptoms during NT-tilt, NT-tilt(cool), or HT-tilt(cool). During the HT-tilt procedure, mean arterial blood pressure (MAP) and cerebral blood flow velocity (CBFV) decreased. However, during HT-tilt(cool), MAP, total peripheral resistance, and CBFV were significantly greater relative to HT-tilt (all P < 0.01). No differences were observed in calculated cerebral vascular resistance between the four conditions. These data suggest that skin-surface cooling prevents the fall in CBFV during upright tilting and improves orthostatic tolerance, presumably via maintenance of MAP. Hence, skin-surface cooling may be a potent countermeasure to protect against orthostatic intolerance observed in heat-stressed humans.

  15. Microstructure and Cerebral Blood Flow within White Matter of the Human Brain: A TBSS Analysis

    PubMed Central

    Giezendanner, Stéphanie; Fisler, Melanie Sarah; Soravia, Leila Maria; Andreotti, Jennifer; Walther, Sebastian; Wiest, Roland; Dierks, Thomas; Federspiel, Andrea

    2016-01-01

    Background White matter (WM) fibers connect different brain regions and are critical for proper brain function. However, little is known about the cerebral blood flow in WM and its relation to WM microstructure. Recent improvements in measuring cerebral blood flow (CBF) by means of arterial spin labeling (ASL) suggest that the signal in white matter may be detected. Its implications for physiology needs to be extensively explored. For this purpose, CBF and its relation to anisotropic diffusion was analyzed across subjects on a voxel-wise basis with tract-based spatial statistics (TBSS) and also across white matter tracts within subjects. Methods Diffusion tensor imaging and ASL were acquired in 43 healthy subjects (mean age = 26.3 years). Results CBF in WM was observed to correlate positively with fractional anisotropy across subjects in parts of the splenium of corpus callosum, the right posterior thalamic radiation (including the optic radiation), the forceps major, the right inferior fronto-occipital fasciculus, the right inferior longitudinal fasciculus and the right superior longitudinal fasciculus. Furthermore, radial diffusivity correlated negatively with CBF across subjects in similar regions. Moreover, CBF and FA correlated positively across white matter tracts within subjects. Conclusion The currently observed findings on a macroscopic level might reflect the metabolic demand of white matter on a microscopic level involving myelination processes or axonal function. However, the exact underlying physiological mechanism of this relationship needs further evaluation. PMID:26942763

  16. Photoperiodic Regulation of Cerebral Blood Flow in White-Footed Mice (Peromyscus leucopus)

    PubMed Central

    Teplitsky, Seth

    2016-01-01

    Abstract Individuals living outside the tropics need to adjust their behavioral and physiological repertoires throughout the year to adapt to the changing seasons. White-footed mice (Peromyscus leucopus) reduce hippocampal volumes, hippocampal-dependent memory function, long-term potentiation, and alter neurogenesis in response to short (winter-like) day lengths (photoperiods). During winter, these mice putatively shunt energy away from the brain to maximize peripheral thermogenesis, immune function, and survival. We hypothesized that these changes in brain function are accompanied by alterations in brain vasculature. We maintained white-footed mice in short (8 h light/16 h dark) or long (16 h light/8 h dark) photoperiods for 8–9 weeks. Mice were then perfused with fluorescein isothiocyanate (FITC)-conjugated tomato (Lycopersicon esculentum) lectin to visualize the perfused cerebrovasculature. Short-day mice reduced hippocampal and cortical capillary density (FITC+ area); vessels isolated from short day-exposed mice expressed higher mRNA levels of the gelatinase matrix metalloproteinase 2 (MMP2). Additionally, short-day mice reduced cerebral blood flow ∼15% compared with their long-day counterparts, as assessed by laser speckle flowmetry. Immunohistochemistry revealed higher levels of MMP2 in the hippocampus of mice maintained in short days compared with long days, potentially contributing to the observed vascular remodeling. These data demonstrate that a discrete environmental signal (i.e., day length) can substantially alter cerebral blood flow in adult mammals. PMID:27570829

  17. Detection of impaired cerebral autoregulation improves by increasing arterial blood pressure variability

    PubMed Central

    Katsogridakis, Emmanuel; Bush, Glen; Fan, Lingke; Birch, Anthony A; Simpson, David M; Allen, Robert; Potter, John F; Panerai, Ronney B

    2013-01-01

    Although the assessment of dynamic cerebral autoregulation (CA) based on measurements of spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CBF) is a convenient and much used method, there remains uncertainty about its reliability. We tested the effects of increasing ABP variability, provoked by a modification of the thigh cuff method, on the ability of the autoregulation index to discriminate between normal and impaired CA, using hypercapnia as a surrogate for dynamic CA impairment. In 30 healthy volunteers, ABP (Finapres) and CBF velocity (CBFV, transcranial Doppler) were recorded at rest and during 5% CO2 breathing, with and without pseudo-random sequence inflation and deflation of bilateral thigh cuffs. The application of thigh cuffs increased ABP and CBFV variabilities and was not associated with a distortion of the CBFV step response estimates for both normocapnic and hypercapnic conditions (P=0.59 and P=0.96, respectively). Sensitivity and specificity of CA impairment detection were improved with the thigh cuff method, with the area under the receiver–operator curve increasing from 0.746 to 0.859 (P=0.031). We conclude that the new method is a safe, efficient, and appealing alternative to currently existing assessment methods for the investigation of the status of CA. PMID:23232946

  18. Base-line O sub 2 extraction influences cerebral blood flow response to hematocrit

    SciTech Connect

    Hudak, M.L.; Tang, Yuilin; Massik, J.; Koehler, R.C.; Traystman, R.J.; Jones, M.D. Jr. )

    1988-01-01

    The authors have shown that the fall in cerebral blood flow (CBF) as hematocrit (Hct) rises is due to the independent effects of increasing red blood cell (RBC) concentration and arterial O{sub 2} content (Ca{sub O{sub 2}}). In the present study, they tested the hypothesis that the magnitude of the effect of RBC concentration depends on the base-line cerebral fractional oxygen extraction (E). Pentobarbital-anesthetized 1- to 7-day-old sheep were first exchange transfused with plasma to lower Hct to 20%. Base-line E was set to either high or low levels by induction of hypocarbia, or hypercarbia. A second isovolemic exchange transfusion with pure methemoglobin-containing adult sheep red cells then raised Hct with no significant increase in Ca{sub O{sub 2}}. Pa{sub CO{sub 2}} was maintained and other variables with potential effect on CBF did not change. CBF corrected for any individual alteration in CMRo{sub 2}. This study supports the hypothesis that the magnitude of the decline in CBF secondary to an increase in RBC concentration depends on the initial E. The effect of RBC concentration on CBF is greatest when E is low.

  19. Influence of Cerebral Blood Flow on Central Sleep Apnea at High Altitude

    PubMed Central

    Burgess, Keith R.; Lucas, Samuel J.E.; Shepherd, Kelly; Dawson, Andrew; Swart, Marianne; Thomas, Kate N.; Lucas, Rebekah A.I.; Donnelly, Joseph; Peebles, Karen C.; Basnyat, Rishi; Ainslie, Philip N.

    2014-01-01

    Study Objectives: To further our understanding of central sleep apnea (CSA) at high altitude during acclimatization, we tested the hypothesis that pharmacologically altering cerebral blood flow (CBF) would alter the severity of CSA at high altitude. Design: The study was a randomized, placebo-controlled single-blind study. Setting: A field study at 5,050 m in Nepal. Patients or Participants: We studied 12 normal volunteers. Interventions: Between days 5 to10 at high altitude, CBF velocity (CBFv) was increased by intravenous (IV) acetazolamide (10 mg/kg) and reduced by oral indomethacin (100 mg). Measurements and Results: Arterial blood gases, hypoxic and hypercapnic ventilatory responses, and CBFv and its reactivity to carbon dioxide were measured awake. Overnight polysomnography was performed. The central apnea-hypopnea index was elevated following administration of indomethacin (89.2 ± 43.7 to 112.5 ± 32.9 events/h; mean ± standard deviation; P < 0.05) and was reduced following IV acetazolamide (89.2 ± 43.7 to 47.1 ± 48.1 events/h; P < 0.001). Intravenous acetazolamide elevated CBFv at high altitude by 28% (95% confidence interval [CI]: 22-34%) but did not affect ventilatory responses. The elevation in CBFv was partly mediated via a selective rise in partial pressure of arterial carbon dioxide (PaCO2) (28 ± 4 to 31 ± 3 mm Hg) and an associated fall in pH (P < 0.01). Oral indomethacin reduced CBFv by 23% (95% CI: 16-30%), blunted CBFv reactivity, and increased the hypercapnic ventilatory response by 66% (95% CI: 30-102%) but had no effect on PaCO2 or pH. Conclusion: Our findings indicate an important role for cerebral blood flow regulation in the pathophysiology of central sleep apnea at high altitude. Citation: Burgess KR, Lucas SJE, Shepherd K, Dawson A, Swart M, Thomas KN, Lucas RAI, Donnelly J, Peebles KC, Basnyat R, Ainslie PN. Influence of cerebral blood flow on central sleep apnea at high altitude. SLEEP 2014;37(10):1679-1687. PMID:25197804

  20. Sufentanil does not increase cerebral blood flow in healthy human volunteers

    SciTech Connect

    Mayer, N.; Weinstabl, C.; Podreka, I.; Spiss, C.K. )

    1990-08-01

    The effect of sufentanil on human cerebral blood flow (CBF) was studied in seven unpremedicated, healthy volunteers 31 +/- 3.5 yr of age (mean +/- SD) and either sex. CBF (ml.100 g-1.min-1) was measured noninvasively with the 133Xe clearance technique and a scintillation camera before and after sufentanil 0.5 micrograms/kg administered intravenously. This technique provides values for global blood flow and for gray and white matter blood flow, and from 13 preselected regions in one hemisphere. After the administration of sufentanil, the volunteers were stimulated verbally in order to prevent their loss of consciousness and hypercarbia. Heart rate (HR), arterial pressure, oxyhemoglobin saturation, and end-tidal CO2 ETCO2 were recorded during the measurements. Neither global CBF (46.1 +/- 1.6 control and 43 +/- 1.9 after sufentanil, mean +/- SEM) nor gray (76.5 +/- 3.2 and 70.9 +/- 6.1) or white (22.7 +/- 1.5 and 24.2 +/- 1.6) matter blood flow changed significantly after sufentanil administration. As well, no significant differences in HR (72 +/- 4 control and 79 +/- 4 beats per min after sufentanil) and ETCO2 (39.8 +/- 1.4 and 41.1 +/- 1.1 mmHg) were observed. It is concluded that sufentanil has no significant effect on CBF in healthy human volunteers.

  1. Non-invasive functional imaging of Cerebral Blood Volume with Vascular-Space-Occupancy (VASO) MRI

    PubMed Central

    Lu, Hanzhang; Hua, Jun; van Zijl, Peter C.M.

    2013-01-01

    Functional MRI (fMRI) based on changes in cerebral blood volume (CBV) can directly probe vasodilatation and vasoconstriction during brain activation or physiologic challenges, and can provide important insights into the mechanism of Blood-Oxygenation-Level-Dependent (BOLD) signal changes. At present, the most widely used CBV fMRI technique in humans is called Vascular-Space-Occupancy (VASO) MRI and this article provides a technical review of this method. VASO MRI utilizes T1 differences between blood and tissue to distinguish these two compartments within a voxel and uses blood-nulling inversion recovery sequence to yield an MR signal proportional to 1-CBV. As such, vasodilatation will result in a VASO signal decrease and vasoconstriction will have the reverse effect. The VASO technique can be performed dynamically with a temporal resolution comparable to several other fMRI methods such as BOLD or Arterial-Spin-Labeling (ASL), and is particularly powerful when conducted in conjunction with these complementary techniques. The pulse sequence and imaging parameters of VASO can be optimized such that the signal change is predominantly of CBV origin, but careful considerations should be taken to minimize other contributions, such as those from the BOLD effect, CBF, and CSF. Sensitivity of the VASO technique remains to be the primary disadvantage when compared to BOLD, but this technique is increasingly demonstrating utility in neuroscientific and clinical applications. PMID:23355392

  2. Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study

    NASA Astrophysics Data System (ADS)

    Parthasarathy, Ashwin B.; Weber, Erica L.; Richards, Lisa M.; Fox, Douglas J.; Dunn, Andrew K.

    2010-11-01

    Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are important for assessing whether blood flow has returned to presurgical baseline levels and for assessing postsurgical tissue viability. Existing techniques for intraoperative monitoring of CBF based on magnetic resonance imaging are expensive and often impractical, while techniques such as indocyanine green angiography cannot produce quantitative measures of blood flow. Laser speckle contrast imaging (LSCI) is an optical technique that has been widely used to quantitatively image relative CBF in animal models in vivo. In a pilot clinical study, we adapted an existing neurosurgical operating microscope to obtain LSCI images in humans in real time during neurosurgery under baseline conditions and after bipolar cautery. Simultaneously recorded ECG waveforms from the patient were used to develop a filter that helped reduce measurement variabilities due to motion artifacts. Results from this study demonstrate the feasibility of using LSCI to obtain blood flow images during neurosurgeries and its capability to produce full field CBF image maps with excellent spatial resolution in real-time with minimal disruption to the surgical procedure.

  3. Effects of anesthesia on the cerebral capillary blood flow in young and old mice

    NASA Astrophysics Data System (ADS)

    Moeini, Mohammad; Tabatabaei, Maryam S.; Bélanger, Samuel; Avti, Pramod; Castonguay, Alexandre; Pouliot, Philippe; Lesage, Frédéric

    2015-03-01

    Despite recent findings on the possible role of age-related cerebral microvasculature changes in cognition decline, previous studies of capillary blood flow in aging (using animal models) are scarce and limited to anesthetized conditions. Since anesthesia can have different effects in young and old animals, it may introduce a confounding effect in aging studies. The present study aimed to eliminate the potential confound introduced by anesthesia by measuring capillary blood flow parameters in both awake conditions and under isoflurane anesthesia. We used 2-photon laser scanning fluorescence microscopy to measure capillary diameter, red blood cell velocity and flux, hematocrit and capillary volumetric flow in individual capillaries in the barrel cortex of 6- and 24-month old C57Bl/6 mice. It was observed that microvascular properties are significantly affected by anesthesia leading to different trends in capillary blood flow parameters with aging when measured under awake or anesthetized conditions. The findings in this study suggest taking extra care in interpreting aging studies from anesthetized animals.

  4. A venous outflow method for continuously monitoring cerebral blood flow in the rat.

    PubMed

    Morii, S; Ngai, A C; Ko, K R; Winn, H R

    1986-02-01

    We analyzed the retroglenoid venous outflow (VOF) technique in the rat to document the validity of this method of measuring cerebral blood flow (CBF). Stereotypic changes in CBF were obtained with VOF during hypercarbia and hypotension. O2 content of retroglenoid venous blood did not differ significantly from O2 content of blood obtained from the sagittal sinus, suggesting minimal extracerebral contamination of the retroglenoid venous blood. This lack of extracerebral contamination was further analyzed using a double tracer technique (125I-labeled serum albumin, 22Na) that quantitated minimal extracerebral contamination in the retroglenoid vein. CBF measurements were made simultaneously using microsphere and VOF methods, and excellent correlation was found between the two techniques over a wide range of CBF during normoxia, hypoxia, and normoxic hypocarbia and hypercarbia. However, a decrease in the ratio of VOF to microsphere CBF was observed during severe normoxic hypotension (mean arterial pressure = 41 +/- 4 mmHg). VOF represented 18% of total CBF as measured by microsphere method. This study indicates that the retroglenoid outflow technique in rats is a valid method of measuring CBF. PMID:3080902

  5. The role of sympathetic reflex control of cerebral blood flow and microcirculation during normoxia and hypoxia

    SciTech Connect

    Kissen, I.

    1989-01-01

    The purpose of this study was to investigate the hypothesis that there is sympathetic reflex regulation of the cerebral blood flow (CBF) and the utilization of microvessels during normoxia and hypoxia. Regional CBF was determined in conscious Long Evans rats with 4-iodo(N-methyl-{sup 14}C)antipyrine. The percentage of the microvessels perfused as determined by comparing perfused microvessels (FITC-dextran), with the total microvasculature (alkaline phosphatase stain). To test this hypothesis, arcs of the proposed reflex were eliminated. The first experiment examined the effect of bilateral superior cervical ganglionectomy on CBF and microcirulation during normoxia and hypoxia. CBF increased during hypoxia from 67 {plus minus} 2 to 115 {plus minus} 3 ml/min/100 g in control, and from 77 {plus minus} 2 to 155 {plus minus} 6 ml/min/100 g in ganglionectomized animals. In control, hypoxic flow to caudal areas was higher than to rostral areas and that difference was prevented by ganglionectomy. Utilization of arterioles during hypoxia increased from 51 {plus minus} 2% to 63 {plus minus} 2% in control, and from 52 {plus minus} 1% to 77 {plus minus} 2% in ganglionectomized group. The percent perfused capillaries during normoxia was 49 {plus minus} 2% in control, and 52 {plus minus} 1% in ganglionectomized group, and during hypoxia it was 73 {plus minus} 2% in both groups. In the second study, cerebral vascular responses to hypoxia were determined after administration of alpha-adrenoceptor antagonists N-methyl chlorpromazine (does not cross the blood-brain barrier), and phenoxybenzamine (crosses the blood-brain barrier). Neither phenoxybenzamine nor N-methyl chlorpromazine affected CBF and microcirculation during normoxia. During hypoxia, they similarly reversed the rostral to caudal gradient of flow, increased utilization of arterioles in rostral brain areas, and did not affect capillaries.

  6. Coupling 1D Navier Stokes equation with autoregulation lumped parameter networks for accurate cerebral blood flow modeling

    NASA Astrophysics Data System (ADS)

    Ryu, Jaiyoung; Hu, Xiao; Shadden, Shawn C.

    2014-11-01

    The cerebral circulation is unique in its ability to maintain blood flow to the brain under widely varying physiologic conditions. Incorporating this autoregulatory response is critical to cerebral blood flow modeling, as well as investigations into pathological conditions. We discuss a one-dimensional nonlinear model of blood flow in the cerebral arteries that includes coupling of autoregulatory lumped parameter networks. The model is tested to reproduce a common clinical test to assess autoregulatory function - the carotid artery compression test. The change in the flow velocity at the middle cerebral artery (MCA) during carotid compression and release demonstrated strong agreement with published measurements. The model is then used to investigate vasospasm of the MCA, a common clinical concern following subarachnoid hemorrhage. Vasospasm was modeled by prescribing vessel area reduction in the middle portion of the MCA. Our model showed similar increases in velocity for moderate vasospasms, however, for serious vasospasm (~ 90% area reduction), the blood flow velocity demonstrated decrease due to blood flow rerouting. This demonstrates a potentially important phenomenon, which otherwise would lead to false-negative decisions on clinical vasospasm if not properly anticipated.

  7. Changes in cerebral blood flow in patients with severe congestive cardiac failure before and after captopril treatment

    SciTech Connect

    Rajagopalan, B.; Raine, A.E.; Cooper, R.; Ledingham, J.G.

    1984-05-31

    The intravenous /sup 133/xenon injection method was used to estimate global cerebral blood flow before and after treatment with captopril in nine patients with severe heart failure. The pretreatment mean blood pressure was 94.9 mm Hg (S.D. 13.9) and fell to 85.1 mm Hg (S.D. 18.1) after treatment with captopril for between four and 15 days. The cerebral blood flow before captopril was 61.1 ml/100 g per minute (S.D. 6.9), which was less than the value of 75.8 ml/100 g per minute found in control subjects. After treatment with captopril the cerebral blood flow increased to 73.8 ml/100 g per minute (S.D. 11.8, p less than 0.01). The fraction of carbon dioxide in the expired air was not significantly different in the two studies (4.1 +/- 0.88 versus 3.97 +/- 0.65). It is concluded that cerebral blood flow is reduced in severe heart failure and can be restored by treatment with captopril, but the reasons for the reduced flow and its improvement after converting enzyme inhibition are not known.

  8. Experimental cerebral malaria pathogenesis--hemodynamics at the blood brain barrier.

    PubMed

    Nacer, Adéla; Movila, Alexandru; Sohet, Fabien; Girgis, Natasha M; Gundra, Uma Mahesh; Loke, P'ng; Daneman, Richard; Frevert, Ute

    2014-12-01

    Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8(+) T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45(hi) CD8(+) T cells, ICAM-1(+) macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8(+) T cells and ICAM(+) macrophages, causes a severe

  9. Functional response of cerebral blood flow induced by somatosensory stimulation in rats with subarachnoid hemorrhage

    NASA Astrophysics Data System (ADS)

    Li, Zhiguo; Huang, Qin; Liu, Peng; Li, Pengcheng; Ma, Lianting; Lu, Jinling

    2015-09-01

    Subarachnoid hemorrhage (SAH) is often accompanied by cerebral vasospasm (CVS), which is the phenomenon of narrowing of large cerebral arteries, and then can produce delayed ischemic neurological deficit (DIND) such as lateralized sensory dysfunction. CVS was regarded as a major contributor to DIND in patients with SAH. However, therapy for preventing vasospasm after SAH to improve the outcomes may not work all the time. It is important to find answers to the relationship between CVS and DIND after SAH. How local cerebral blood flow (CBF) is regulated during functional activation after SAH still remains poorly understood, whereas, the regulation of CBF may play an important role in weakening the impact of CVS on cortex function. Therefore, it is worthwhile to evaluate the functional response of CBF in the activated cortex in an SAH animal model. Most evaluation of the effect of SAH is presently carried out by neurological behavioral scales. The functional imaging of cortical activation during sensory stimulation may help to reflect the function of the somatosensory cortex more locally than the behavioral scales do. We investigated the functional response of CBF in the somatosensory cortex induced by an electrical stimulation to contralateral forepaw via laser speckle imaging in a rat SAH model. Nineteen Sprague-Dawley rats from two groups (control group, n=10 and SAH group, n=9) were studied. SAH was induced in rats by double injection of autologous blood into the cisterna magna after CSF aspiration. The same surgical procedure was applied in the control group without CSF aspiration or blood injection. Significant CVS was found in the SAH group. Meanwhile, we observed a delayed peak of CBF response in rats with SAH compared with those in the control group, whereas no significant difference was found in magnitude, duration, and areas under curve of relative CBF changes between the two groups. The results suggest that the regulation function of local CBF during

  10. Experimental Cerebral Malaria Pathogenesis—Hemodynamics at the Blood Brain Barrier

    PubMed Central

    Nacer, Adéla; Movila, Alexandru; Sohet, Fabien; Girgis, Natasha M.; Gundra, Uma Mahesh; Loke, P'ng; Daneman, Richard; Frevert, Ute

    2014-01-01

    Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8+ T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45hi CD8+ T cells, ICAM-1+ macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8+ T cells and ICAM+ macrophages, causes a severe restriction in

  11. Ellagic acid improves electrocardiogram waves and blood pressure against global cerebral ischemia rat experimental models

    PubMed Central

    Nejad, Khojasteh Hoseiny; Dianat, Mahin; Sarkaki, Alireza; Naseri, Mohammad Kazem Gharib; Badavi, Mohammad; Farbood, Yaghoub

    2015-01-01

    Background: Global cerebral ischemia (GCIR) arises in patients that are shown a variety of clinical difficulty including cardiac arrest, asphyxia, and shock. In spite of advances in understanding of the brain, ischemia and protective effects to improve ischemic injury still remain unknown. The aim of our study was to investigate the effect of ellagic acid (EA) pretreatment in the rat models of global cerebral ischemia reperfusion. Methods: This experimental study was conducted in 2014 at the Physiology Research Center of the Ahvaz Jundishapur University of Medical Sciences in Ahvaz, Iran. Adult male Wistar rats (250–300 g) were used in this study. GCIR was induced by bilateral vertebral and common carotid arteries occlusion (4-VO). 32 rats were divided randomly to four groups: 1) So (Sham) received normal saline as vehicle of EA, 2) EA, 3) normal saline + GCIR, and 4) EA + GCIR. After anesthesia (a mix of xylazine and ketamine), animal subjected to 20 minutes of ischemia followed by 30 minutes of reperfusion in related groups. EA (100 mg/kg, dissolved in normal saline) or 1.5 ml/kg normal saline was administered (gavage, 10 days) to the related groups. EEG was recorded from NTS in GCIR treated groups. Results: Present data showed that: 1) EEG in GCIR treated groups was flattened; 2) Blood pressure, voltage of QRS and P-R interval were reduced significantly in the ischemic groups compared to before ischemia, and pretreatment with EA prevented this reduction; and 3) MDA level and heart rate was increased by GCIR and pretreatment with EA reduced MDA level and restored the HR to normal level. Conclusion: Results indicate that global cerebral ischemia-reperfusion impairs certain heart functions and ellagic acid as an antioxidant can restore these parameters. The results of this study suggest the possible utility of ellagic acid in patients with brain stroke. PMID:26396728

  12. Longitudinal decrease in blood oxygenation level dependent response in cerebral amyloid angiopathy

    PubMed Central

    Switzer, Aaron R.; McCreary, Cheryl; Batool, Saima; Stafford, Randall B.; Frayne, Richard; Goodyear, Bradley G.; Smith, Eric E.

    2016-01-01

    Lower blood oxygenation level dependent (BOLD) signal changes in response to a visual stimulus in functional magnetic resonance imaging (fMRI) have been observed in cross-sectional studies of cerebral amyloid angiopathy (CAA), and are presumed to reflect impaired vascular reactivity. We used fMRI to detect a longitudinal change in BOLD responses to a visual stimulus in CAA, and to determine any correlations between these changes and other established biomarkers of CAA progression. Data were acquired from 22 patients diagnosed with probable CAA (using the Boston Criteria) and 16 healthy controls at baseline and one year. BOLD data were generated from the 200 most active voxels of the primary visual cortex during the fMRI visual stimulus (passively viewing an alternating checkerboard pattern). In general, BOLD amplitudes were lower at one year compared to baseline in patients with CAA (p = 0.01) but were unchanged in controls (p = 0.18). The longitudinal difference in BOLD amplitudes was significantly lower in CAA compared to controls (p < 0.001). White matter hyperintensity (WMH) volumes and number of cerebral microbleeds, both presumed to reflect CAA-mediated vascular injury, increased over time in CAA (p = 0.007 and p = 0.001, respectively). Longitudinal increases in WMH (rs = 0.04, p = 0.86) or cerebral microbleeds (rs = − 0.18, p = 0.45) were not associated with the longitudinal decrease in BOLD amplitudes. PMID:27104140

  13. The effects of perturbed cerebral blood flow and cerebrovascular reactivity on structural MRI and behavioral readouts in mild traumatic brain injury.

    PubMed

    Long, Justin A; Watts, Lora T; Li, Wei; Shen, Qiang; Muir, Eric R; Huang, Shiliang; Boggs, Robert C; Suri, Abhinav; Duong, Timothy Q

    2015-11-01

    This study investigated the effects of perturbed cerebral blood flow (CBF) and cerebrovascular reactivity (CR) on relaxation time constant (T2), apparent diffusion coefficient (ADC), fractional anisotropy (FA), and behavioral scores at 1 and 3 hours, 2, 7, and 14 days after traumatic brain injury (TBI) in rats. Open-skull TBI was induced over the left primary forelimb somatosensory cortex (N=8 and 3 sham). We found the abnormal areas of CBF and CR on days 0 and 2 were larger than those of the T2, ADC, and FA abnormalities. In the impact core, CBF was reduced on day 0, increased to 2.5 times of normal on day 2, and returned toward normal by day 14, whereas in the tissue surrounding the impact, hypoperfusion was observed on days 0 and 2. CR in the impact core was negative, most severe on day 2 but gradually returned toward normal. T2, ADC, and FA abnormalities in the impact core were detected on day 0, peaked on day 2, and pseudonormalized by day 14. Lesion volumes peaked on day 2 and were temporally correlated with forelimb asymmetry and foot-fault scores. This study quantified the effects of perturbed CBF and CR on structural magnetic resonance imaging and behavioral readouts. PMID:26104285

  14. Melatonin reduces traumatic brain injury-induced oxidative stress in the cerebral cortex and blood of rats

    PubMed Central

    Şenol, Nilgün; Nazıroğlu, Mustafa

    2014-01-01

    Free radicals induced by traumatic brain injury have deleterious effects on the function and antioxidant vitamin levels of several organ systems including the brain. Melatonin possesses antioxidant effect on the brain by maintaining antioxidant enzyme and vitamin levels. We investigated the effects of melatonin on antioxidant ability in the cerebral cortex and blood of traumatic brain injury rats. Results showed that the cerebral cortex β-carotene, vitamin C, vitamin E, reduced glutathione, and erythrocyte reduced glutathione levels, and plasma vitamin C level were decreased by traumatic brain injury whereas they were increased following melatonin treatment. In conclusion, melatonin seems to have protective effects on traumatic brain injury-induced cerebral cortex and blood toxicity by inhibiting free radical formation and supporting antioxidant vitamin redox system. PMID:25206769

  15. Detection by PCR of Toxoplasma gondii in blood in the diagnosis of cerebral toxoplasmosis in patients with AIDS.

    PubMed Central

    Lamoril, J; Molina, J M; de Gouvello, A; Garin, Y J; Deybach, J C; Modaï, J; Derouin, F

    1996-01-01

    The polymerase chain reaction (PCR) for amplification of Toxoplasma gondii DNA was performed prospectively in the blood of 19 patients with AIDS and cerebral toxoplasmosis. The B1 gene and TGR1E sequence were used as targets and results were confirmed by hybridisation. Controls consisted of 24 HIV infected patients with tissue culture proven T gondii parasitaemia and 57 HIV infected patients without toxoplasmosis. PCR was positive with both targets in 20 of 24 samples (84%) from patients with parasitaemia. Three of 57 samples (5%) from patients without toxoplasmosis were PCR positive with either target, but none was positive with both targets. Only three of the 19 patients (16%) with cerebral toxoplasmosis had a positive PCR with both targets before the start of specific treatment. PCR performed in blood is of little diagnostic value in cases of cerebral toxoplasmosis but could be useful in patients with disseminated infection. Images PMID:8666697

  16. Nafamostat mesilate protects against acute cerebral ischemia via blood-brain barrier protection.

    PubMed

    Wang, Jing; Li, Chenhui; Chen, Tao; Fang, Yinquan; Shi, Xinzhong; Pang, Tao; Zhang, Luyong; Liao, Hong

    2016-06-01

    Serine proteases, such as thrombin, are contributors to the disruption of the blood-brain barrier (BBB) and exacerbate brain damage during ischemic stroke, for which the current clinical therapy remains unsatisfactory. However, the effect of nafamostat mesilate (NM), a synthetic serine protease inhibitor, on BBB disruption following cerebral ischemia is unknown. Here, we investigated the in vivo effect of NM on BBB integrity in rats subjected to transient middle cerebral artery occlusion (MCAO) and explored the possible mechanism in an in vitro BBB model comprising rat brain microvascular endothelial cells and astrocytes after oxygen and glucose deprivation (OGD) in the presence of thrombin. The results showed that NM treatment remarkably attenuated transient MCAO-induced brain infarcts, brain oedema and motor dysfunction in addition to BBB disruption, which might be related to changes in tight junction protein expression and localization. Meanwhile, NM preserved BBB integrity and alleviated the changes in tight junction protein expression and localization and cytoskeleton rearrangement in rat brain microvascular endothelial cells via thrombin inhibition. Our findings suggest that NM treatment can preserve BBB integrity through the inhibition of thrombin, which might be correlated with the regulation of PKCα/RhoA/MLC2 pathway components. PMID:26861077

  17. The effect of amphetamine on regional cerebral blood flow during cognitive activation in schizophrenia

    SciTech Connect

    Daniel, D.G.; Weinberger, D.R.; Jones, D.W.; Zigun, J.R.; Coppola, R.; Handel, S.; Bigelow, L.B.; Goldberg, T.E.; Berman, K.F.; Kleinman, J.E. )

    1991-07-01

    To explore the role of monoamines on cerebral function during specific prefrontal cognitive activation, we conducted a double-blind placebo-controlled crossover study of the effects of 0.25 mg/kg oral dextroamphetamine on regional cerebral blood flow (rCBF) as determined by 133Xe dynamic single-photon emission-computed tomography (SPECT) during performance of the Wisconsin Card Sorting Test (WCST) and a sensorimotor control task. Ten patients with chronic schizophrenia who had been stabilized for at least 6 weeks on 0.4 mg/kg haloperidol participated. Amphetamine produced a modest, nonsignificant, task-independent, global reduction in rCBF. However, the effect of amphetamine on task-dependent activation of rCBF (i.e., WCST minus control task) was striking. Whereas on placebo no significant activation of rCBF was seen during the WCST compared with the control task, on amphetamine significant activation of the left dorsolateral prefrontal cortex (DLPFC) occurred (p = 0.0006). Both the mean number of correct responses and the mean conceptual level increased (p less than 0.05) with amphetamine relative to placebo. In addition, with amphetamine, but not with placebo, a significant correlation (p = -0.71; p less than 0.05) emerged between activation of DLPFC rCBF and performance of the WCST task. These findings are consistent with animal models in which mesocortical catecholaminergic activity modulates and enhances the signal-to-noise ratio of evoked cortical activity.

  18. Transient receptor potential (TRP) channels, vascular tone and autoregulation of cerebral blood flow.

    PubMed

    Brayden, Joseph E; Earley, Scott; Nelson, Mark T; Reading, Stacey

    2008-09-01

    Members of the transient receptor potential (TRP) channel superfamily are present in vascular smooth muscle cells and play important roles in the regulation of vascular contractility. The TRPC3 and TRPC6 channels are activated by stimulation of several excitatory receptors in vascular smooth muscle cells. Activation of these channels leads to myocyte depolarization, which stimulates Ca2+ entry via voltage-dependent Ca2+ channels (VDCC), leading to vasoconstriction. The TRPV4 channels in arterial myocytes are activated by epoxyeicosatrienoic acids, and activation of the channels enhances Ca2+ spark and transient Ca2+-sensitive K+ channel activity, thereby hyperpolarizing and relaxing vascular smooth muscle cells. The TRPC6 and TRPM4 channels are activated by mechanical stimulation of cerebral artery myocytes. Subsequent depolarization and activation of VDCC Ca2+ entry is directly linked to the development of myogenic tone in vitro and to autoregulation of cerebral blood flow in vivo. These findings imply a fundamental importance of TRP channels in the regulation of vascular smooth muscle tone and suggest that TRP channels could be important targets for drug therapy under conditions in which vascular contractility is disturbed (e.g. hypertension, stroke, vasospasm). PMID:18215190

  19. Dimethyl fumarate attenuates cerebral edema formation by protecting the blood-brain barrier integrity.

    PubMed

    Kunze, Reiner; Urrutia, Andrés; Hoffmann, Angelika; Liu, Hui; Helluy, Xavier; Pham, Mirko; Reischl, Stefan; Korff, Thomas; Marti, Hugo H

    2015-04-01

    Brain edema is a hallmark of various neuropathologies, but the underlying mechanisms are poorly understood. We aim to characterize how tissue hypoxia, together with oxidative stress and inflammation, leads to capillary dysfunction and breakdown of the blood-brain barrier (BBB). In a mouse stroke model we show that systemic treatment with dimethyl fumarate (DMF), an antioxidant drug clinically used for psoriasis and multiple sclerosis, significantly prevented edema formation in vivo. Indeed, DMF stabilized the BBB by preventing disruption of interendothelial tight junctions and gap formation, and decreased matrix metalloproteinase activity in brain tissue. In vitro, DMF directly sustained endothelial tight junctions, inhibited inflammatory cytokine expression, and attenuated leukocyte transmigration. We also demonstrate that these effects are mediated via activation of the redox sensitive transcription factor NF-E2 related factor 2 (Nrf2). DMF activated the Nrf2 pathway as shown by up-regulation of several Nrf2 target genes in the brain in vivo, as well as in cerebral endothelial cells and astrocytes in vitro, where DMF also increased protein abundance of nuclear Nrf2. Finally, Nrf2 knockdown in endothelial cells aggravated subcellular delocalization of tight junction proteins during ischemic conditions, and attenuated the protective effect exerted by DMF. Overall, our data suggest that DMF protects from cerebral edema formation during ischemic stroke by targeting interendothelial junctions in an Nrf2-dependent manner, and provide the basis for a completely new approach to treat brain edema. PMID:25725349

  20. Intraoperative sup 133 Xe cerebral blood flow measurements by intravenous versus intracarotid methods

    SciTech Connect

    Young, W.L.; Prohovnik, I.; Schroeder, T.; Correll, J.W.; Ostapkovich, N. )

    1990-10-01

    To document the comparability of cerebral blood flow (CBF) values determined by quantification of 133Xe washout after either intravenous or intracarotid administration, 12 patients undergoing elective carotid endarterectomy anesthetized with N2O/O2 and either isoflurane or halothane were studied. Scintillation counters were placed over the middle cerebral artery territory ipsilateral to the operated carotid artery. CBF was measured by the intravenous method during dissection of the carotid sheath and was calculated as the initial slope index from head washout curves collected for 11 min after injection of 10-20 mCi 133Xe in saline into a large vein. Immediately prior to carotid occlusion, CBF was determined by direct injection of 1 mCi 133Xe in saline into either the internal carotid artery or the common carotid artery with the external carotid artery occluded. For the intracarotid injections, the initial slope was calculated from the 1st min of washout. Data were analyzed by linear regression and analysis of variance. Values are expressed as mean +/- SD. The mean CBF for intravenous and intracarotid methods were both 29 +/- 10 ml.100 g-1.min-1. The correlation between CBF measured by intravenous and intracarotid methods was excellent and was described by the line y = x + 0.6, r = 0.92. We conclude that in the flow range studied, the intravenous technique may be applied to measure CBF in physiologically stable situations in which direct intracarotid injection is not feasible.

  1. Highly accurate thermal flow microsensor for continuous and quantitative measurement of cerebral blood flow.

    PubMed

    Li, Chunyan; Wu, Pei-ming; Wu, Zhizhen; Limnuson, Kanokwan; Mehan, Neal; Mozayan, Cameron; Golanov, Eugene V; Ahn, Chong H; Hartings, Jed A; Narayan, Raj K

    2015-10-01

    Cerebral blood flow (CBF) plays a critical role in the exchange of nutrients and metabolites at the capillary level and is tightly regulated to meet the metabolic demands of the brain. After major brain injuries, CBF normally decreases and supporting the injured brain with adequate CBF is a mainstay of therapy after traumatic brain injury. Quantitative and localized measurement of CBF is therefore critically important for evaluation of treatment efficacy and also for understanding of cerebral pathophysiology. We present here an improved thermal flow microsensor and its operation which provides higher accuracy compared to existing devices. The flow microsensor consists of three components, two stacked-up thin film resistive elements serving as composite heater/temperature sensor and one remote resistive element for environmental temperature compensation. It operates in constant-temperature mode (~2 °C above the medium temperature) providing 20 ms temporal resolution. Compared to previous thermal flow microsensor based on self-heating and self-sensing design, the sensor presented provides at least two-fold improvement in accuracy in the range from 0 to 200 ml/100 g/min. This is mainly achieved by using the stacked-up structure, where the heating and sensing are separated to improve the temperature measurement accuracy by minimization of errors introduced by self-heating. PMID:26256480

  2. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures

    SciTech Connect

    Gozukirmizi, E.; Meyer, J.S.; Okabe, T.; Amano, T.; Mortel, K.; Karacan, I.

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

  3. Cerebral blood flow velocity in humans exposed to 24 h of head-down tilt

    NASA Technical Reports Server (NTRS)

    Kawai, Y.; Murthy, G.; Watenpaugh, D. E.; Breit, G. A.; Deroshia, C. W.; Hargens, A. R.

    1993-01-01

    This study investigates cerebral blood flow (CBF) velocity in humans before, during, and after 24 h of 6 deg head-down tilt (HDT), which is a currently accepted experimental model to simulate microgravity. CBF velocity was measured by use of the transcranial Doppler technique in the right middle cerebral artery of eight healthy male subjects. Mean CBF velocity increased from the pre-HDT upright seated baseline value of 55.5 +/- 3.7 (SE) cm/s to 61.5 +/- 3.3 cm/s at 0.5 h of HDT, reached a peak value of 63.2 +/- 4.1 cm/s at 3 h of HDT, and remained significantly above the pre-HDT baseline for over 6 h of HDT. During upright seated recovery, mean CBF velocity decreased to 87 percent of the pre-HDT baseline value. Mean CBF velocity correlated well with calculated intracranial arterial pressure (IAP). As analyzed by linear regression, mean CBF velocity = 29.6 + 0.32IAP. These results suggest that HDT increases CBF velocity by increasing IAP during several hours after the onset of microgravity. Importantly, the decrease in CBF velocity after HDT may be responsible, in part, for the increased risk of syncope observed in subjects after prolonged bed rest and also in astronauts returning to Earth.

  4. Effects of noise and mental task performance upon changes in cerebral blood flow parameters

    PubMed Central

    Nowakowska-Kotas, Marta; Pokryszko-Dragan, Anna; Brodowski, Mirosław; Szydło, Mariusz; Podemski, Ryszard

    2015-01-01

    The objectives of this paper were to determine whether traffic noise influences the parameters of cerebral blood flow (CBF) measured by functional transcranial Doppler sonography (fTCD) during the performance of mental tasks, and to see whether impact of noise on CBF changes with age. The study comprised 36 healthy volunteers, 22 women and 14 men, aged 25-49 years. The fTCD was performed using a fixed 2-MHz probe, aiming for an evaluation of mean velocity (MFV) and the pulsatility index (PI) in the middle cerebral artery (MCA) on both sides. Subsequently, fTCD was monitored: At rest; during performance of the Paced Auditory Serial Addition Test (PASAT); during exposure to traffic noise; and during concomitant exposure to noise and PASAT performance. MFV and PI were compared for particular conditions and correlated with age. During exposure to noise, flow parameters did not change significantly. PASAT performance in silence increased MFV and decreased PI in MCA on both sides. During PASAT performance, on exposure to noise, MCV and PI changed significantly only in the left MCA. However, values of MFV were significantly lower during noise than in silence. Correlations with age were noted for velocities in the right MCA during PASAT performance in silence and for PI on both sides during PASAT performed in noise conditions. Noise impairs the CBF during mental tasks. A comparison of changes in CBF parameters correlated with age suggests that the involvement of the nondominant hemisphere in managing with noise effects increases with age. PMID:26572702

  5. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures.

    PubMed

    Gozukirmizi, E; Meyer, J S; Okabe, T; Amano, T; Mortel, K; Karacan, I

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements. PMID:7163722

  6. Cerebral blood flow in the newborn infant: comparison of Doppler ultrasound and /sup 133/xenon clearance

    SciTech Connect

    Greisen, G.; Johansen, K.; Ellison, P.H.; Fredriksen, P.S.; Mali, J.; Friis-Hansen, B.

    1984-03-01

    Two techniques of Doppler ultrasound examination, continuous-wave and range-gated, applied to the anterior cerebral artery and to the internal carotid artery, were compared with /sup 133/xenon clearance after intravenous injection. Thirty-two sets of measurements were obtained in 16 newborn infants. The pulsatility index, the mean flow velocity, and the end-diastolic flow velocity were read from the Doppler recordings. Mean cerebral blood flow was estimated from the /sup 133/Xe clearance curves. The correlation coefficients between the Doppler and the /sup 133/Xe measurements ranged from 0.41 to 0.82. In the subset of 16 first measurements in each infant, there were no statistically significant differences between the correlation coefficients of the various Doppler ultrasound variables, but the correlation coefficients were consistently lower for the pulsatility index than for mean flow velocity or end-diastolic flow velocity, and they were consistently higher for the range-gated than for the continuous-wave Doppler technique.

  7. Effects of noise and mental task performance upon changes in cerebral blood flow parameters.

    PubMed

    Nowakowska-Kotas, Marta; Pokryszko-Dragan, Anna; Brodowski, Mirosław; Szydło, Mariusz; Podemski, Ryszard

    2015-01-01

    The objectives of this paper were to determine whether traffic noise influences the parameters of cerebral blood flow (CBF) measured by functional transcranial Doppler sonography (fTCD) during the performance of mental tasks, and to see whether impact of noise on CBF changes with age. The study comprised 36 healthy volunteers, 22 women and 14 men, aged 25-49 years. The fTCD was performed using a fixed 2-MHz probe, aiming for an evaluation of mean velocity (MFV) and the pulsatility index (PI) in the middle cerebral artery (MCA) on both sides. Subsequently, fTCD was monitored: At rest; during performance of the Paced Auditory Serial Addition Test (PASAT); during exposure to traffic noise; and during concomitant exposure to noise and PASAT performance. MFV and PI were compared for particular conditions and correlated with age. During exposure to noise, flow parameters did not change significantly. PASAT performance in silence increased MFV and decreased PI in MCA on both sides. During PASAT performance, on exposure to noise, MCV and PI changed significantly only in the left MCA. However, values of MFV were significantly lower during noise than in silence. Correlations with age were noted for velocities in the right MCA during PASAT performance in silence and for PI on both sides during PASAT performed in noise conditions. Noise impairs the CBF during mental tasks. A comparison of changes in CBF parameters correlated with age suggests that the involvement of the nondominant hemisphere in managing with noise effects increases with age. PMID:26572702

  8. Mechanical indentation improves cerebral blood oxygenation signal quality of functional near-infrared spectroscopy (fNIRS) during breath holding

    NASA Astrophysics Data System (ADS)

    Vogt, William C.; Romero, Edwin; LaConte, Stephen M.; Rylander, Christopher G.

    2013-03-01

    Functional near-infrared spectroscopy (fNIRS) is a well-known technique for non-invasively measuring cerebral blood oxygenation, and many studies have demonstrated that fNIRS signals can be related to cognitive function. However, the fNIRS signal is attenuated by the skin, while scalp blood content has been reported to influence cerebral oxygenation measurements. Mechanical indentation has been shown to increase light transmission through soft tissues by causing interstitial water and blood flow away from the compressed region. To study the effects of indentation on fNIRS, a commercial fNIRS system with 16 emitter/detector pairs was used to measure cerebral blood oxygenation at 2 Hz. This device used diffuse reflectance at 730 nm and 850 nm to calculate deoxy- and oxy-hemoglobin concentrations. A borosilicate glass hemisphere was epoxied over each sensor to function as both an indenter and a lens. After placing the indenter/sensor assembly on the forehead, a pair of plastic bands was placed on top of the fNIRS headband and strapped to the head to provide uniform pressure and tightened to approx. 15 N per strap. Cerebral blood oxygenation was recorded during a breath holding regime (15 second hold, 15 second rest, 6 cycles) in 4 human subjects both with and without the indenter array. Results showed that indentation increased raw signal intensity by 85 +/- 35%, and that indentation increased amplitude of hemoglobin changes during breath cycles by 313% +/- 105%. These results suggest that indentation improves sensing of cerebral blood oxygenation, and may potentially enable sensing of deeper brain tissues.

  9. A Functional Perspective on the Embryology and Anatomy of the Cerebral Blood Supply.

    PubMed

    Menshawi, Khaled; Mohr, Jay P; Gutierrez, Jose

    2015-05-01

    The anatomy of the arterial system supplying blood to the brain can influence the development of arterial disease such as aneurysms, dolichoectasia and atherosclerosis. As the arteries supplying blood to the brain develop during embryogenesis, variation in their anatomy may occur and this variation may influence the development of arterial disease. Angiogenesis, which occurs mainly by sprouting of parent arteries, is the first stage at which variations can occur. At day 24 of embryological life, the internal carotid artery is the first artery to form and it provides all the blood required by the primitive brain. As the occipital region, brain stem and cerebellum enlarge; the internal carotid supply becomes insufficient, triggering the development of the posterior circulation. At this stage, the posterior circulation consists of a primitive mesh of arterial networks that originate from projection of penetrators from the distal carotid artery and more proximally from carotid-vertebrobasilar anastomoses. These anastomoses regress when the basilar artery and the vertebral arteries become independent from the internal carotid artery, but their persistence is not uncommon in adults (e.g., persistent trigeminal artery). Other common remnants of embryological development include fenestration or duplication (most commonly of the basilar artery), hypoplasia (typically of the posterior communicating artery) or agenesis (typically of the anterior communicating artery). Learning more about the hemodynamic consequence that these variants may have on the brain territories they supply may help understand better the underlying physiopathology of cerebral arterial remodeling and stroke in patients with these variants. PMID:26060802

  10. Experimental arrest of cerebral blood flow in human subjects: the red wing studies revisited.

    PubMed

    Smith, Brian A; Clayton, Ellen Wright; Robertson, David

    2011-01-01

    Loss of consciousness in pilots during rapid ascent after bombing missions was a major problem in World War II, and experiments were undertaken to study the cause of this phenomenon. Postulating impaired cerebral blood flow as a likely mechanism, the investigators developed a neck device, the KRA Cuff, which when inflated could shut off blood supply to the brain. With cessation of blood flow for up to 100 seconds, the investigators observed a sequence of responses, including unconsciousness, followed by dilated pupils, tonic/clonic movements, loss of bladder and eventually bowel control, and appearance of pathological reflexes. This study, carried out in prisoners and patients with schizophrenia in 1941-42, largely disappeared from public discourse for a number of years. It has received occasional attention subsequently and been considered controversial. Recently discovered records, including extensive written and photographic data from the studies, shed new light on the methods and motives of the research team. We describe here this new information and its implications for the scientific and ethical assessment of the study. PMID:21532128

  11. Quantitative BOLD: Mapping of Human Cerebral Deoxygenated Blood Volume and Oxygen Extraction Fraction: Default State

    PubMed Central

    He, Xiang; Yablonskiy, Dmitriy A.

    2014-01-01

    Since Ogawa et al. (Proc Natl Acad Sci USA 1990;87:9868–9872) made the fundamental discovery of blood oxygenation level-dependent (BOLD) contrast in MRI, most efforts have been directed toward the study of dynamic BOLD (i.e., temporal changes in the MRI signal during changes in brain activity). However, very little progress has been made in elucidating the nature of BOLD contrast during the resting or baseline state of the brain, which is important for understanding normal human performance because it accounts for most of the enormous energy budget of the brain. It is also crucial for deciphering the consequences of baseline-state impairment by cerebral vascular diseases. The objective of this study was to develop a BOLD MR-based method that allows quantitative evaluation of tissue hemodynamic parameters, such as the blood volume, deoxyhemoglobin concentration, and oxygen extraction fraction (OEF). The proposed method, which we have termed quantitative BOLD (qBOLD), is based on an MR signal model that incorporates prior knowledge about brain tissue composition and considers signals from gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and blood. A 2D gradient-echo sampling of spin-echo (GESSE) pulse sequence is used for the acquisition of the MRI signal. The method is applied to estimate the hemodynamic parameters of the normal human brain in the baseline state. PMID:17191227

  12. A Functional Perspective on the Embryology and Anatomy of the Cerebral Blood Supply

    PubMed Central

    Menshawi, Khaled; Mohr, Jay P

    2015-01-01

    The anatomy of the arterial system supplying blood to the brain can influence the development of arterial disease such as aneurysms, dolichoectasia and atherosclerosis. As the arteries supplying blood to the brain develop during embryogenesis, variation in their anatomy may occur and this variation may influence the development of arterial disease. Angiogenesis, which occurs mainly by sprouting of parent arteries, is the first stage at which variations can occur. At day 24 of embryological life, the internal carotid artery is the first artery to form and it provides all the blood required by the primitive brain. As the occipital region, brain stem and cerebellum enlarge; the internal carotid supply becomes insufficient, triggering the development of the posterior circulation. At this stage, the posterior circulation consists of a primitive mesh of arterial networks that originate from projection of penetrators from the distal carotid artery and more proximally from carotid-vertebrobasilar anastomoses. These anastomoses regress when the basilar artery and the vertebral arteries become independent from the internal carotid artery, but their persistence is not uncommon in adults (e.g., persistent trigeminal artery). Other common remnants of embryological development include fenestration or duplication (most commonly of the basilar artery), hypoplasia (typically of the posterior communicating artery) or agenesis (typically of the anterior communicating artery). Learning more about the hemodynamic consequence that these variants may have on the brain territories they supply may help understand better the underlying physiopathology of cerebral arterial remodeling and stroke in patients with these variants. PMID:26060802

  13. A single subcutaneous bolus of erythropoietin normalizes cerebral blood flow autoregulation after subarachnoid haemorrhage in rats

    PubMed Central

    Springborg, Jacob Bertram; Ma, XiaoDong; Rochat, Per; Knudsen, Gitte Moos; Amtorp, Ole; Paulson, Olaf B; Juhler, Marianne; Olsen, Niels Vidiendal

    2002-01-01

    Systemic administration of recombinant erythropoietin (EPO) has been demonstrated to mediate neuroprotection. This effect of EPO may in part rely on a beneficial effect on cerebrovascular dysfunction leading to ischaemic neuronal damage. We investigated the in vivo effects of subcutaneously administered recombinant EPO on impaired cerebral blood flow (CBF) autoregulation after experimental subarachnoid haemorrhage (SAH).Four groups of male Sprague-Dawley rats were studied: group A, sham operation plus vehicle; group B, sham operation plus EPO; group C, SAH plus vehicle; group D, SAH plus EPO. SAH was induced by injection of 0.07 ml of autologous blood into the cisterna magna. EPO (400 iu kg−1 s.c.) or vehicle was given immediately after the subarachnoid injection of blood or saline. Forty-eight hours after the induction of SAH, CBF autoregulatory function was evaluated using the intracarotid 133Xe method.CBF autoregulation was preserved in both sham-operated groups (lower limits of mean arterial blood pressure: 91±3 and 98±3 mmHg in groups A and B, respectively). In the vehicle treated SAH-group, autoregulation was abolished and the relationship between CBF and blood pressure was best described by a single linear regression line. A subcutaneous injection of EPO given immediately after the induction of SAH normalized autoregulation of CBF (lower limit in group D: 93±4 mmHg, NS compared with groups A and B).Early activation of endothelial EPO receptors may represent a potential therapeutic strategy in the treatment of cerebrovascular perturbations after SAH. PMID:11834631

  14. Two-photon microscopy with double-circle trajectories for in vivo cerebral blood flow measurements

    NASA Astrophysics Data System (ADS)

    Landolt, Andrin; Obrist, Dominik; Wyss, Matthias; Barrett, Matthew; Langer, Dominik; Jolivet, Renaud; Soltysinski, Tomasz; Roesgen, Thomas; Weber, Bruno

    2013-05-01

    Scanning microscopes normally use trajectories which produce full-frame images of an object at a low frame rate. Time-resolved measurements are possible if scans along a single line are repeated at a high rate. In conjunction with fluorescence labeling techniques, in vivo recording of blood flow in single capillaries is possible. The present work investigates scanning with double-circle trajectories to measure blood flow simultaneously in several vessels of a capillary network. With the trajectory centered near a bifurcation, a double circle crosses each vessel twice, creating a sensing gate for passing dark red blood cells in fluorescently labeled plasma. From the stack of scans repeated at 1,300 Hz, the time-resolved velocity is retrieved using an image correlation approach. Single bifurcation events can be identified from a few fluorescently labeled red blood cells. The applicability of the method for in vivo measurements is illustrated on the basis of two-photon laser scanning microscopy of the cerebral capillary network of mice. Its performance is assessed with synthetic data generated from a two-phase model for the perfusion in a capillary network. The calculation of velocities is found to be sufficiently robust for a wide range of conditions. The achievable limits depend significantly on the experimental conditions and are estimated to be in the 1 μm/s (velocity) and 0.1 s (time resolution) ranges, respectively. Some manual fine-tuning is required for optimal performance in terms of accuracy and time resolution. Further work may lead to improved reliability with which bifurcation events are identified in the algorithm and to include red blood cell flux and hematocrit measurements. With the capability for time-resolved measurements in all vessels of a bifurcation, double-circle scanning trajectories allow a detailed study of the dynamics in vascular networks.

  15. Sevoflurane and nitrous oxide increase regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in a drug-specific manner in human volunteers.

    PubMed

    Kolbitsch, C; Lorenz, I H; Hörmann, C; Kremser, C; Schocke, M; Felber, S; Moser, P L; Hinteregger, M; Pfeiffer, K P; Benzer, A

    2001-12-01

    Anesthesia for diagnostic procedures, e.g., MRI measurements, has increasingly used sevoflurane and nitrous oxide in recent years. Sevoflurane and nitrous oxide are known cerebrovasodilatators, however, which potentially interferes with MRI examination of cerebral hemodynamics. To compare the effects of relevant equianesthetic concentrations (0.4 MAC) of both drugs on regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) we used contrast-enhanced magnetic resonance imaging (MRI) perfusion measurement, which has the advantage of providing regional anatomic resolution. Sevoflurane increased rCBF more than did nitrous oxide in all regions except in parietal and frontal gray matter. Nitrous oxide, by contrast, increased rCBV in most of the gray matter regions more than did sevoflurane. In summary we show that, in contrast to nitrous oxide, sevoflurane supratentorially reversed the anterior-posterior gradient in rCBF and typically redistributed rCBF to infratentorial gray matter. In contrast, nitrous oxide increased rCBV more than did sevoflurane. Both inhalational anesthetics had a drug-specific influence on cerebral hemodynamics, which is of importance when interpreting MRI studies of cerebral hemodynamics in anesthetized patients. PMID:11804751

  16. Cerebral blood flow differences between long-term meditators and non-meditators.

    PubMed

    Newberg, Andrew B; Wintering, Nancy; Waldman, Mark R; Amen, Daniel; Khalsa, Dharma S; Alavi, Abass

    2010-12-01

    We have studied a number of long-term meditators in previous studies. The purpose of this study was to determine if there are differences in baseline brain function of experienced meditators compared to non-meditators. All subjects were recruited as part of an ongoing study of different meditation practices. We evaluated 12 advanced meditators and 14 non-meditators with cerebral blood flow (CBF) SPECT imaging at rest. Images were analyzed with both region of interest and statistical parametric mapping. The CBF of long-term meditators was significantly higher (p<.05) compared to non-meditators in the prefrontal cortex, parietal cortex, thalamus, putamen, caudate, and midbrain. There was also a significant difference in the thalamic laterality with long-term meditators having greater asymmetry. The observed changes associated with long-term meditation appear in structures that underlie the attention network and also those that relate to emotion and autonomic function. PMID:20570534

  17. Cerebral blood flow and red cell delivery in normal subjects and in multiple sclerosis

    SciTech Connect

    Swank, R.L.; Roth, J.G.; Woody, D.C. Jr.

    1983-01-01

    Regional cerebral blood flow (rCBF) was determined in 77 normal females and 53 normal males of different ages and in 26 men and 45 women with multiple sclerosis by the inhalation of radioactive Xe133 method. In the normal subjects the CBF was relatively high in the teens and fell, at first rapidly and then slowly in both sexes with age. During adult life the flow in females was significantly higher than in males. The delivery of packed red cells (RCD) was determined by multiplying the CBF by the percentage concentration of red cells (HCT). The RCD for both sexes was nearly the same. In the patients with multiple sclerosis there occurred a progressive generalized decrease in CBF and in RCD with age which was significantly greater than observed in normal subjects. The rate of decrease in CBF and RCD correlated directly with the rate of progress of the disease.

  18. Regional cerebral blood flow in schizophrenics. Tests using the xenon Xe 133 inhalation method

    SciTech Connect

    Ariel, R.N.; Golden, C.J.; Berg, R.A.; Quaife, M.A.; Dirksen, J.W.; Forsell, T.; Wilson, J.; Graber, B.

    1983-03-01

    Measurements of intrahemispheric and bilateral regional cerebral blood flow (CBF) for gray and white matter were compared in 29 schizophrenic patients and 22 normal controls, using the xenon Xe 133 inhalation method. Results showed significantly lower CBF values for all brain regions in the schizophrenic group, and post hoc comparisons showed relatively greater reduced gray-matter CBF values in the anterior areas of the brain. There was also a left-hemisphere frontal loss similar to that reported previously, although it was in the context of a generalized loss in anterior functioning. Interhemispheric comparison within both groups showed no differences between homologous regions for gray matter, and greater white-matter CBF values in the right hemisphere than in the left hemisphere. The findings support a hypothesis of a bilateral anterior deficit in schizophrenia.

  19. Patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent

    NASA Astrophysics Data System (ADS)

    Takizawa, Kenji; Schjodt, Kathleen; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

    2012-12-01

    We present the special arterial fluid mechanics techniques we have developed for patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent. These techniques are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stent. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents. We also compare the flow patterns obtained with the finite- and zero-thickness representations of the stent.

  20. 3-D phantom to simulate cerebral blood flow and metabolic images for PET

    SciTech Connect

    Hoffman, E.J.; Cutler, P.D.; Digby, W.M.; Mazziotta, J.C. . Nuclear Medicine Lab.)

    1990-04-01

    A 3-dimensional brain phantom has been developed to simulate the activity distributions found in the human brain in the cerebral blood flow and metabolism studies currently employed in PET. The phantom has a single contiguous chamber and utilizes thin layers of lucite to provide apparent relative concentrations of 5, 1 and 0 for gray matter, white matter and ventricles, respectively, in the brain. The phantom and an ideal image set were created from the same set of data. Thus, the user has a basis for comparing measured images with an ideal image set which enables the user to make quantitative evaluation of the errors in PET studies with a data set similar to that obtained in patient studies.

  1. Age and regional cerebral blood flow at rest and during cognitive activity

    SciTech Connect

    Gur, R.C.; Gur, R.E.; Obrist, W.D.; Skolnick, B.E.; Reivich, M.

    1987-07-01

    The relationship between age and regional cerebral blood flow (rCBF) activation for cognitive tasks was investigated with the xenon (Xe 133) inhalation technique. The sample consisted of 55 healthy subjects, ranging in age from 18 to 72 years, who were studied during rest and during the performance of verbal analogy and spatial orientation tasks. The dependent measures were indexes of gray-matter rCBF and average rCBF (gray and white matter) as well as the percentage of gray-matter tissue. Advanced age was associated with reduced flow, particularly pronounced in anterior regions. However, the extent and pattern of rCBF changes during cognition was unaffected by age. For the percentage of gray matter, there was a specific reduction in anterior regions of the left hemisphere. The findings suggest the utility of this research paradigm for investigating neural underpinnings of the effects of dementia on cognitive functioning, relative to the effects of normal aging.

  2. Smart catheter flow sensor for real-time continuous regional cerebral blood flow monitoring

    NASA Astrophysics Data System (ADS)

    Li, Chunyan; Wu, Pei-Ming; Hartings, Jed A.; Wu, Zhizhen; Ahn, Chong H.; LeDoux, David; Shutter, Lori A.; Narayan, Raj K.

    2011-12-01

    We present a smart catheter flow sensor for real-time, continuous, and quantitative measurement of regional cerebral blood flow using in situ temperature and thermal conductivity compensation. The flow sensor operates in a constant-temperature mode and employs a periodic heating and cooling technique. This approach ensures zero drift and provides highly reliable data with microelectromechanical system-based thin film sensors. The developed flow sensor has a sensitivity of 0.973 mV/ml/100 g/min in the range from 0 to 160 ml/100 g/min with a linear correlation coefficient of R2 = 0.9953. It achieves a resolution of 0.25 ml/100 g/min and an accuracy better than 5 ml/100 g/min.

  3. Role of cerebral blood volume changes in brain specific-gravity measurements

    SciTech Connect

    Picozzi, P.; Todd, N.V.; Crockard, A.H.

    1985-05-01

    Cerebral blood volume (CBV) was calculated in gerbils from specific-gravity (SG) changes between normal and saline-perfused brains. Furthermore, changes in CBV were investigated during ischemia using carbon-14-labeled dextran (MW 70,000) as an intravascular marker. Both data were used to evaluate the possible error due to a change in CBV on the measurement of ischemic brain edema by the SG method. The methodological error found was 0.0004 for a 100% CBV change. This error is insignificant, being less than the standard deviation in the SG measured for the gerbil cortex. Thus, CBV changes are not responsible for the SG variations observed during the first phase of ischemia. These variations are better explained as an increase of brain water content during ischemia.

  4. Epileptic Seizure Detection and Prediction Based on Continuous Cerebral Blood Flow Monitoring--a Review.

    PubMed

    Tewolde, Senay; Oommen, Kalarickal; Lie, Donald Y C; Zhang, Yuanlin; Chyu, Ming-Chien

    2015-01-01

    Epilepsy is the third most common neurological illness, affecting 1% of the world's population. Despite advances in medicine, about 25 to 30% of the patients do not respond to or cannot tolerate the severe side effects of medical treatment, and surgery is not an option for the majority of patients with epilepsy. The objective of this article is to review the current state of research on seizure detection based on cerebral blood flow (CBF) data acquired by thermal diffusion flowmetry (TDF), and CBF-based seizure prediction. A discussion is provided on the applications, advantages, and disadvantages of TDF in detecting and localizing seizure foci, as well as its role in seizure prediction. Also presented are an overview of the present challenges and possible future research directions (along with methodological guidelines) of the CBF-based seizure detection and prediction methods. PMID:26288885

  5. Modeling of Cerebral Oxygen Transport Based on In vivo Microscopic Imaging of Microvascular Network Structure, Blood Flow, and Oxygenation

    PubMed Central

    Gagnon, Louis; Smith, Amy F.; Boas, David A.; Devor, Anna; Secomb, Timothy W.; Sakadžić, Sava

    2016-01-01

    Oxygen is delivered to brain tissue by a dense network of microvessels, which actively control cerebral blood flow (CBF) through vasodilation and contraction in response to changing levels of neural activity. Understanding these network-level processes is immediately relevant for (1) interpretation of functional Magnetic Resonance Imaging (fMRI) signals, and (2) investigation of neurological diseases in which a deterioration of neurovascular and neuro-metabolic physiology contributes to motor and cognitive decline. Experimental data on the structure, flow and oxygen levels of microvascular networks are needed, together with theoretical methods to integrate this information and predict physiologically relevant properties that are not directly measurable. Recent progress in optical imaging technologies for high-resolution in vivo measurement of the cerebral microvascular architecture, blood flow, and oxygenation enables construction of detailed computational models of cerebral hemodynamics and oxygen transport based on realistic three-dimensional microvascular networks. In this article, we review state-of-the-art optical microscopy technologies for quantitative in vivo imaging of cerebral microvascular structure, blood flow and oxygenation, and theoretical methods that utilize such data to generate spatially resolved models for blood flow and oxygen transport. These “bottom-up” models are essential for the understanding of the processes governing brain oxygenation in normal and disease states and for eventual translation of the lessons learned from animal studies to humans.

  6. Autistic Traits, ADHD Symptoms, Neurological Soft Signs and Regional Cerebral Blood Flow in Adults with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Manouilenko, Irina; Pagani, Marco; Stone-Elander, Sharon; Odh, Richard; Brolin, Fredrik; Hatherly, Robert; Jacobsson, Hans; Larsson, Stig A.; Bejerot, Susanne

    2013-01-01

    The resting regional cerebral blood flow (rCBF) patterns related to co-occurring symptoms such as inattention, hyperactivity, neurological soft signs and motor problems have not yet been disclosed in autism spectrum disorders (ASD). In this study thirteen adults with ASD and ten matched neurotypical controls underwent PET. The scores of rating…

  7. CT perfusion cerebral blood volume does not always predict infarct core in acute ischemic stroke.

    PubMed

    d'Esterre, Christopher D; Roversi, Gloria; Padroni, Marina; Bernardoni, Andrea; Tamborino, Carmine; De Vito, Alessandro; Azzini, Cristiano; Marcello, Onofrio; Saletti, Andrea; Ceruti, Stefano; Lee, Ting Yim; Fainardi, Enrico

    2015-10-01

    We investigated the practical clinical utility of the CT perfusion (CTP) cerebral blood volume (CBV) parameter for differentiating salvageable from non-salvageable tissue in acute ischemic stroke (AIS). Fifty-five patients with AIS were imaged within 6 h from onset using CTP. Admission CBV defect (CBVD) volume was outlined using previously established gray and white matter CBV thresholds for infarct core. Admission cerebral blood flow (CBF) hypoperfusion and CBF/CBV mismatch were visually evaluated. Truncation of the ischemic time-density curve (ITDC) and hypervolemia status at admission, recanalization at 24-h CT angiography, hemorrhagic transformation (HT) at 24 h and/or 7-day non-contrast CT (NCCT), final infarct volume as indicated by 3-month NCCT defect (NCCTD) and 3-month modified Rankin Score were determined. Patients with recanalization and no truncation had the highest correlation (R = 0.81) and regression slope (0.80) between CBVD and NCCTD. Regression slopes were close to zero for patients with admission hypervolemia with/without recanalization. Hypervolemia underestimated (p = 0.02), while recanalization and ITDC truncation overestimated (p = 0.03) the NCCTD. Among patients with confirmed recanalization at 24 h, 38 % patients had an admission CBF/CBV mismatch within normal appearing areas on respective NCCT. 83 % of these patients developed infarction in admission hypervolemic CBF/CBV mismatch tissue. A reduction in CBV is a valuable predictor of infarct core when the acquisition of ITDC data is complete and hypervolemia is absent within the tissue destined to infarct. Raised or normal CBV is not always indicative of salvageable tissue, contrary to the current definition of penumbra. PMID:25981225

  8. Factors Contributing to Massive Blood Loss on Peripartum Hysterectomy for Abnormally Invasive Placenta: Who Bleeds More?

    PubMed Central

    Usui, Rie; Suzuki, Hirotada; Baba, Yosuke

    2016-01-01

    Introduction. To identify factors that determine blood loss during peripartum hysterectomy for abnormally invasive placenta (AIP-hysterectomy). Methods. We reviewed all of the medical charts of 11,919 deliveries in a single tertiary perinatal center. We examined characteristics of AIP-hysterectomy patients, with a single experienced obstetrician attending all AIP-hysterectomies and using the same technique. Results. AIP-hysterectomy was performed in 18 patients (0.15%: 18/11,919). Of the 18, 14 (78%) had a prior cesarean section (CS) history and the other 4 (22%) were primiparous women. Planned AIP-hysterectomy was performed in 12/18 (67%), with the remaining 6 (33%) undergoing emergent AIP-hysterectomy. Of the 6, 4 (4/6: 67%) patients were primiparous women. An intra-arterial balloon was inserted in 9/18 (50%). Women with the following three factors significantly bled less in AIP-hysterectomy than its counterpart: the employment of an intra-arterial balloon (4,448 ± 1,948 versus 8,861 ± 3,988 mL), planned hysterectomy (5,003 ± 2,057 versus 9,957 ± 4,485 mL), and prior CS (5,706 ± 2,727 versus 9,975 ± 5,532 mL). Patients with prior CS (−) bled more: this may be because these patients tended to undergo emergent surgery or attempted placental separation. Conclusion. Patients with intra-arterial balloon catheter insertion bled less on AIP-hysterectomy. Massive bleeding occurred in emergent AIP-hysterectomy without prior CS.

  9. The effect of the excitatory amino acid receptor antagonist dizocilipine maleate (MK-801) on hemispheric cerebral blood flow and metabolism in dogs: modification by prior complete cerebral ischemia.

    PubMed

    Perkins, W J; Lanier, W L; Karlsson, B R; Milde, J H; Michenfelder, J D

    1989-09-25

    The effect of the N-methyl-D-aspartate (NMDA) receptor antagonist dizociplipine maleate (MK-801) on cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), intracranial pressure and systemic variables was examined in 6 normal dogs (Group I). In 6 additional dogs (Group II), the effects of a prior 11 min episode of complete cerebral ischemia on the response to dizocilipine was studied. CBF was measured with a sagittal sinus outflow technique and CMRO2 was calculated as the product of CBF and the arterial to sagittal sinus O2 content difference. Dizocilipine was administered as a 150 micrograms/kg i.v. bolus followed by a 75 micrograms.kg-1.h-1 infusion for 90 min. Plasma dizocilipine levels were greater than 25 ng/ml for the duration of the infusion. The CSF levels were approximately half the plasma levels. Five minutes after initiation of dizocilipine treatment, Group I dogs experienced a 63% increase in heart rate (P less than 0.01) and an 8% decrease in the mean arterial blood pressure (P less than 0.05). Over the same time interval. CBF increased by 85% (P less than 0.01) and intracranial pressure nearly doubled (P less than 0.05). In addition, dizocilipine treatment in all Group I animals resulted in EEG quasiperiodic bursts of delta-waves and polyspikes on a background of beta-activity. With the exception of the intracranial pressure, the above changes in systemic and cerebral variables persisted for the duration of the drug infusion. Intracranial pressure was no longer significantly elevated after 80 min of drug infusion. Hemispheric CMRO2 was unchanged by dizocilipine in Group I dogs. There was a decrease in the cortical glucose level at the end of the study, but no significant change in phosphocreatine, ATP, lactate, or energy charge when compared with 6 laboratory normals. An identical dose of dizocilipine administered after an 11 min episode of complete cerebral ischemia resulted in no significant changes in either cerebral or systemic

  10. Cerebral blood flow and metabolism in children with severe head injuries. Part 2: Cerebrovascular resistance and its determinants.

    PubMed Central

    Sharples, P M; Matthews, D S; Eyre, J A

    1995-01-01

    It has been proposed that in children with severe head injuries the cerebral circulation does not respond appropriately to normal physiological control mechanisms, making children more susceptible than adults to low cerebrovascular resistance, increased cerebral blood flow (cerebral hyperaemia), and raised intracranial pressure. To investigate this issue, 122 serial measurements of cerebrovascular resistance in 17 children with severe head injuries have been performed and related to cerebral perfusion pressure, arterial CO2 (PaCO2), arterial oxygen content (AO2), and the cerebral metabolic rate of oxygen (CMRO2). Cerebrovascular resistance values (mean (SD) 1.54 (0.61) mm Hg.ml-1.100 g.min) were normal or raised in most cases; 71 values (58%) were within the normal range, 39 (32%) above the upper limit, and only 12 (10%) below the lower limit. There was a significant correlation between cerebral perfusion pressure and cerebrovascular resistance (r = 0.32, p = 0.0003), suggesting preservation of pressure autoregulation. This correlation was absent in four of the five children who died or survived with severe handicap. Analysis by multilevel modelling indicated that, as in normal subjects, CMRO2, CPP, AO2, PaCO2, and cerebrovenous pH were important independent determinants of cerebrovascular resistance. The results indicate that normal cerebrovascular reactivity is often preserved in children with severe head injuries but may be impaired in the most severely injured patients. PMID:7876844

  11. Functional photoacoustic micro-imaging of cerebral hemodynamic changes in single blood vessels after photo-induced brain stroke

    NASA Astrophysics Data System (ADS)

    Liao, Lun-De; Chen, You-Yin; Lin, Chin-Teng; Li, Meng-Lin

    2013-03-01

    Studying the functional hemodynamic roles of individual cerebral cortical arterioles in maintaining both the structure and function of cortical regions during and after brain stroke in small animals is an important issue. Recently, functional photoacoustic microscopy (fPAM) has been proved as a reliable imaging technique to probe the total hemoglobin concentration (HbT), cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) in single cerebral blood vessels of rats. Here, we report the application of fPAM associated with electrophysiology recordings to investigating functional hemodynamic changes in single cortical arterioles of rats with electrical forepaw stimulation after photo-induced ischemic stroke. Because of the weak optical focusing nature of our fPAM system, photo-induced ischemic stroke targeting single cortical arterioles can be easily conducted with simple adaptation. Functional HbT, CBV and SO2 changes associated with the induced stroke in selected arterioles from the anterior cerebral artery system were imaged with 36 x 65-μm spatial resolution. Experimental results showed that after photo-occlusion of a single arteriole, the functional changes of nearby arterioles in cerebral cortex only can be observed immediately after the stroke. After a few minutes of stroke onset, there are no significant functional changes under the forepaw stimulation, suggesting that alternate blood flow routes are not actively recruited. The fPAM with electrophysiology recordings complements existing imaging techniques and has the potential to offer a favorable tool for explicitly studying cerebral hemodynamics in small animal models of photo-indcued ischemic stroke.

  12. Influence of Vascular Variant of the Posterior Cerebral Artery (PCA) on Cerebral Blood Flow, Vascular Response to CO2 and Static Functional Connectivity

    PubMed Central

    Emmert, Kirsten; Zöller, Daniela; Preti, Maria Giulia; Van De Ville, Dimitri; Giannakopoulos, Panteleimon; Haller, Sven

    2016-01-01

    Introduction The fetal origin of the posterior cerebral artery (fPCA) is a frequent vascular variant in 11–29% of the population. For the fPCA, blood flow in the PCA originates from the anterior instead of the posterior circulation. We tested whether this blood supply variant impacts the cerebral blood flow assessed by arterial spin labeling (ASL), cerebrovascular reserve as well as resting-state static functional connectivity (sFC) in the sense of a systematic confound. Methods The study included 385 healthy, elderly subjects (mean age: 74.18 years [range: 68.9–90.4]; 243 female). Participants were classified into normal vascular supply (n = 296, 76.88%), right fetal origin (n = 23, 5.97%), left fetal origin (n = 16, 4.16%), bilateral fetal origin (n = 4, 1.04%), and intermediate (n = 46, 11.95%, excluded from further analysis) groups. ASL-derived relative cerebral blood flow (relCBF) maps and cerebrovascular reserve (CVR) maps derived from a CO2 challenge with blocks of 7% CO2 were compared. Additionally, sFC between 90 regions of interest (ROIs) was compared between the groups. Results CVR was significantly reduced in subjects with ipsilateral fPCA, most prominently in the temporal lobe. ASL yielded a non-significant trend towards reduced relCBF in bilateral posterior watershed areas. In contrast, conventional atlas-based sFC did not differ between groups. Conclusions In conclusion, fPCA presence may bias the assessment of cerebrovascular reserve by reducing the response to CO2. In contrast, its effect on ASL-assessed baseline perfusion was marginal. Moreover, fPCA presence did not systematically impact resting-state sFC. Taken together, this data implies that perfusion variables should take into account the vascularization patterns. PMID:27532633

  13. Using peripheral smear review, age and absolute lymphocyte count as predictors of abnormal peripheral blood lymphocytoses diagnosed by flow cytometry.

    PubMed

    Andrews, Jared M; Cruser, Dan L; Myers, Jerome B; Fernelius, Colby A; Holm, Mitchel T; Waldner, Dale L

    2008-09-01

    Absolute lymphocytosis in the elderly raises the possibility of malignancy and generally warrants further investigation. To better correlate clinical variables with the frequency of neoplastic lymphoid processes in this population, we retrospectively reviewed archived flow cytometric analyses from peripheral blood specimens on patients of 50 years of age and older that had been deemed suspicious for a lymphoproliferative process after peripheral smear review. Age, absolute lymphocyte count (ALC), white blood cell count and relative lymphocyte count were correlated with the results of flow cytometry. Of 71 total cases, 42 (59%) had an abnormal immunophenotype. Independent variables that showed significant differences between normal and abnormal immunophenotype were mean age (p = 0.001) and ALC (p = 0.0032). We combined age and absolute lymphocyte count variables to look for the best possible cutoff values to predict the likelihood of an abnormal immunophenotype. ALC cutoff values of >or=4 x 10(9) cells/L for patients over 67 years of age, and >6.7 x 10(9) cells/L for patients between 50 and 67 years of age, had a high sensitivity for detecting an abnormal immunophenotype. PMID:18798107

  14. Performance of the CellaVision® DM96 system for detecting red blood cell morphologic abnormalities

    PubMed Central

    Horn, Christopher L.; Mansoor, Adnan; Wood, Brenda; Nelson, Heather; Higa, Diane; Lee, Lik Hang; Naugler, Christopher

    2015-01-01

    Background: Red blood cell (RBC) analysis is a key feature in the evaluation of hematological disorders. The gold standard light microscopy technique has high sensitivity, but is a relativity time-consuming and labor intensive procedure. This study tested the sensitivity and specificity of gold standard light microscopy manual differential to the CellaVision® DM96 (CCS; CellaVision, Lund, Sweden) automated image analysis system, which takes digital images of samples at high magnification and compares these images with an artificial neural network based on a database of cells and preclassified according to RBC morphology. Methods: In this study, 212 abnormal peripheral blood smears within the Calgary Laboratory Services network of hospital laboratories were selected and assessed for 15 different RBC morphologic abnormalities by manual microscopy. The same samples were reassessed as a manual addition from the instrument screen using the CellaVision® DM96 system with 8 microscope high power fields (×100 objective and a 22 mm ocular). The results of the investigation were then used to calculate the sensitivity and specificity of the CellaVision® DM96 system in reference to light microscopy. Results: The sensitivity ranged from a low of 33% (RBC agglutination) to a high of 100% (sickle cells, stomatocytes). The remainder of the RBC abnormalities tested somewhere between these two extremes. The specificity ranged from 84% (schistocytes) to 99.5% (sickle cells, stomatocytes). Conclusions: Our results showed generally high specificities but variable sensitivities for RBC morphologic abnormalities. PMID:25774322

  15. Red Blood Cells from Individuals with Abdominal Obesity or Metabolic Abnormalities Exhibit Less Deformability upon Entering a Constriction

    PubMed Central

    Zeng, Nancy F.; Mancuso, Jordan E.; Zivkovic, Angela M.; Smilowitz, Jennifer T.; Ristenpart, William D.

    2016-01-01

    Abdominal obesity and metabolic syndrome (MS) are multifactorial conditions associated with increased risk of cardiovascular disease and type II diabetes mellitus. Previous work has demonstrated that the hemorheological profile is altered in patients with abdominal obesity and MS, as evidenced for example by increased whole blood viscosity. To date, however, no studies have examined red blood cell (RBC) deformability of blood from individuals with obesity or metabolic abnormalities under typical physiological flow conditions. In this study, we pumped RBCs through a constriction in a microfluidic device and used high speed video to visualize and track the mechanical behavior of ~8,000 RBCs obtained from either healthy individuals (n = 5) or obese participants with metabolic abnormalities (OMA) (n = 4). We demonstrate that the OMA+ cells stretched on average about 25% less than the healthy controls. Furthermore, we examined the effects of ingesting a high-fat meal on RBC mechanical dynamics, and found that the postprandial period has only a weak effect on the stretching dynamics exhibited by OMA+ cells. The results suggest that chronic rigidification of RBCs plays a key role in the increased blood pressure and increased whole blood viscosity observed in OMA individuals and was independent of an acute response triggered by consumption of a high-fat meal. Trial Registration ClinicalTrials.gov NCT01803633 PMID:27258098

  16. Validation of diffuse correlation spectroscopic measurement of cerebral blood flow using phase-encoded velocity mapping magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Buckley, Erin M.; Hance, Dalton; Pawlowski, Thomas; Lynch, Jennifer; Wilson, Felice B.; Mesquita, Rickson C.; Durduran, Turgut; Diaz, Laura K.; Putt, Mary E.; Licht, Daniel J.; Fogel, Mark A.; Yodh, Arjun G.

    2012-03-01

    Diffuse correlation spectroscopy (DCS) is a novel optical technique that appears to be an excellent tool for assessing cerebral blood flow in a continuous and non-invasive manner at the bedside. We present new clinical validation of the DCS methodology by demonstrating strong agreement between DCS indices of relative cerebral blood flow and indices based on phase-encoded velocity mapping magnetic resonance imaging (VENC MRI) of relative blood flow in the jugular veins and superior vena cava. Data were acquired from 46 children with single ventricle cardiac lesions during a hypercapnia intervention. Significant increases in cerebral blood flow, measured both by DCS and by VENC MRI, as well as significant increases in oxyhemoglobin concentration, and total hemoglobin concentration, were observed during hypercapnia. Comparison of blood flow changes measured by VENC MRI in the jugular veins and by DCS revealed a strong linear relationship, R=0.88, p<0.001, slope=0.91+/-0.07. Similar correlations were observed between DCS and VENC MRI in the superior vena cava, R=0.77, slope=0.99+/-0.12, p<0.001. The relationship between VENC MRI in the aorta and DCS, a negative control, was weakly correlated, R=0.46, slope=1.77+/-0.45, p<0.001.

  17. Relationship of Early Spontaneous Type V Blood Pressure Fluctuation after Thrombolysis in Acute Cerebral Infarction Patients and the Prognosis.

    PubMed

    Zuo, Lian; Wan, Ting; Xu, Xiahong; Liu, Feifeng; Li, Changsong; Li, Ying; Zhang, Yue; Zhang, Jing; Bao, Huan; Li, Gang

    2016-01-01

    We examined the relationship between an early spontaneous type V blood pressure fluctuation and the post-thrombolysis prognosis of patients with acute cerebral infarction. Patients were admitted consecutively. All patients were categorized into the type V blood pressure fluctuation group or non-type V blood pressure group. Their blood pressure was monitored before thrombolysis and until 6 h after thrombolysis. Baseline data and clinical outcomes were compared. Of 170 patients, 43 (25.2%) had an early type V blood pressure fluctuation. The National Institute of Health Stroke Scale (NIHSS) score before thrombolysis and 24 h after thrombolysis, and the modified Rankin scale score at 90 days differed significantly between the two groups (P < 0.05). Multiple logistic regression analysis showed that an unfavorable prognosis at 3 months was associated with the NIHSS score before thrombolysis (P = 0.000) but probably not with this blood pressure fluctuation (P = 0.058). An early spontaneous type V blood pressure fluctuation is common in patients with acute cerebral infarction who received venous thrombolysis, especially if they have a higher NIHSS score before thrombolysis. The type V blood pressure fluctuation may not influence patients' prognosis; however, this needs to be confirmed in future trials. PMID:27278121

  18. Effect of 4-hydroxypyrazolo (3,4-d) pyrimidine (allopurinol) on postirradiation cerebral blood flow: implications of free radical involvement

    SciTech Connect

    Cockerham, L.G.; Arroyo, C.M.; Hampton, J.D.

    1988-01-01

    In an attempt to elucidate mechanisms underlying the irradiation-induced decrease in regional cerebral blood flow (rCBF) in primates, hippocampal and hypothalamic blood flows of rhesus monkeys were measured by hydrogen clearance, before and after exposure to 100 Gy, whole body, gamma irradiation. Systemic blood pressures were monitored simultaneously. Compared to control animals, the irradiated monkeys exhibited an abrupt decline in systemic blood pressure to 35% of the preirradiation level within 10 min postirradiation, falling to 12% by 60 min. A decrease in hippocampal blood flow to 32% of the preirradiation level was noted at 10 min postirradiation, followed by a slight recovery to 43% at 30 min and a decline to 23% by 60 min. The hypothalamic blood flow of the same animals showed a steady decrease to 43% of the preirradiation levels by 60 min postirradiation. The postradiation systemic blood pressure of the allopurinol treated monkeys was not statistically different from the untreated, irradiated monkeys and was statistically different from the control monkeys. However, the treated, irradiated monkeys displayed rCBF values that were not significantly different from the nonirradiated controls. These findings suggest the involvement of free radicals in the postirradiation decrease in regional cerebral blood flow but not necessarily in the postirradiation hypotension seen in the primate.

  19. The effect of intravenous epoprostenol (prostacyclin, PGI2) on cerebral blood flow and cardiac output in man.

    PubMed Central

    Cook, P J; Maidment, C G; Dandona, P; Hutton, R A; James, I M

    1983-01-01

    Epoprostenol (prostacyclin, PGI2) was given intravenously to seven healthy volunteers in a dose of 4 ng kg-1 min-1 over a 30 min period. Diastolic blood pressure fell but there was no change in cardiac output. The mean PGI2 concentration at the end of the infusion was 0.43 ng/ml (1.1 nM) and a significant inhibition of ADP-induced platelet aggregation occurred. Although obvious facial flushing occurred in all subjects and some subjects complained of headache, cerebral blood flow tended to fall. The results do not support the hypothesis that PGI2 acts as a physiological vasodilator involved in the homeostasis of normal cerebral blood flow. PMID:6362696

  20. Cerebral blood flow and oxygenation in ovine fetus: responses to superimposed hypoxia at both low and high altitude

    PubMed Central

    Peňa, Jorge Pereyra; Tomimatsu, Takuji; Hatran, Douglas P; McGill, Lisa L; Longo, Lawrence D

    2007-01-01

    For the fetus, although the roles of arterial blood gases are recognized to be critical in the regulation of cerebral blood flow (CBF) and cerebral oxygenation, the relation of CBF, cortical tissue PO2 (t PO2), sagittal sinus PO2, and related indices of cerebral oxygenation to arterial blood gases are not well defined. This is particularly true for that fetus subjected to long-term hypoxia (LTH). In an effort to elucidate these interrelations, we tested the hypothesis that in the fetus acclimatized to high altitude, cerebral oxygenation is not compromised relative to that at low altitude. By use of a laser Doppler flowmeter with a fluorescent O2 probe, in near-term fetal sheep at low altitude (n = 8) and those acclimatized to high altitude hypoxia (3801 m for 90 ± 5 days; n = 6), we measured laser Doppler CBF (LD-CBF), t PO2, and related variables in response to 40 min superimposed hypoxia. At both altitudes, fetal LD-CBF, cerebral O2 delivery, t PO2, and several other variables including sagittal sinus PO2, correlated highly with arterial PO2 (Pa,O2). In response to superimposed hypoxia (Pa,O2 = 11 ± 1 Torr), LD-CBF was significantly blunted at high altitude, as compared with that at low altitude. In the two altitude groups fetal cerebral oxygenation was similar under both control conditions and with superimposed hypoxia, cortical t PO2 decreasing from 8 ± 1 and 6 ± 1 Torr, respectively, to 2 ± 1 Torr. Also, for these conditions sagittal sinus PO2 and [HbO2] values were similar. In response to superimposed hypoxia, cerebral metabolic rate for O2 decreased ∼50% in each group (P < 0.05). For both the fetus at low altitude and that acclimatized to high altitude LTH, we present the first dose–response data on the relation of LD-CBF, cortical t PO2, and sagittal sinus blood gas values to Pa,O2. In addition, despite differences in several variables, the fetus at high altitude showed evidence of successful acclimatization, supporting the hypothesis that such

  1. Angiographic analysis of blood flow modification in cerebral aneurysm models with a new asymmetric stent

    PubMed Central

    Wang, Zhou; Ionita, Ciprian; Rudin, Stephen; Hoffmann, Kenneth R.; Paxton, Adam B.; Bednarek, Daniel R.

    2011-01-01

    We have built new asymmetric stents for minimally invasive endovascular treatment of cerebral aneurysms. Each asymmetric stent consists of a commercial stent with a micro-welded circular mesh patch. The blood flow modification in aneurysm-vessel phantoms due to these stents was evaluated using x-ray angiographic analysis. However, the density difference between the radiographic contrast and the blood gives rise to a gravity effect, which was evaluated using an initial optical dye-dilution experiment. For the radiographic evaluations, curved-vessel phantoms instead of simple straight side-wall aneurysm phantoms were used in the characterization of meshes/stents. Six phantoms (one untreated, one treated with a commercial stent, and four treated with different asymmetric stents) with similar morphologies were used for comparison. We calculated time-density curves of the aneurysm region and then calculated the peak value (Pk) and washout rate (1/τ) after analytical curve fitting. Flow patterns in the angiograms showed reduction of vortex flow and slow washout in the dense mesh patch treated aneurysms. The meshes reduced Pk down to 21% and 1/τ down to 12% of the values for the untreated case. In summary, new asymmetric stents were constructed and their evaluation demonstrates that they may be useful in the endovascular treatment of aneurysms. PMID:21886414

  2. Regional cerebral blood flow study with 123I-IMP in patients with degenerative dementia

    SciTech Connect

    Ohnishi, T.; Hoshi, H.; Nagamachi, S.; Jinnouchi, S.; Futami, S.; Watanabe, K.; Mitsuyama, Y. )

    1991-05-01

    Regional cerebral blood flow was evaluated by single-photon emission CT (SPECT) with 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) in 11 patients with dementia of the Alzheimer type, three patients with progressive dementia and motor neuron disease, and eight healthy control subjects. Regional blood flow measurements in the bilateral frontal, parietal association, and temporal cortices were lower in the Alzheimer dementia patients than in controls. Flow deficits in the parietal association cortex were demonstrated in all patients with Alzheimer-type dementia; these deficits were correlated with the severity of disease. Lateral hemispheric asymmetry was seen in nine of 11 patients with Alzheimer-type dementia. In all three patients with progressive dementia and motor neuron disease, flow deficits were demonstrated in the bilateral frontal and temporal cortices, but no flow deficits were seen in the parietal association cortex. Brain SPECT with 123I-IMP may be useful in the differential diagnosis and evaluation of the severity of degenerative dementia.

  3. Cardiorespiratory fitness mediates the effects of aging on cerebral blood flow

    PubMed Central

    Zimmerman, Benjamin; Sutton, Bradley P.; Low, Kathy A.; Fletcher, Mark A.; Tan, Chin Hong; Schneider-Garces, Nils; Li, Yanfen; Ouyang, Cheng; Maclin, Edward L.; Gratton, Gabriele; Fabiani, Monica

    2014-01-01

    The brain's vasculature is likely to be subjected to the same age-related physiological and anatomical changes affecting the rest of the cardiovascular system. Since aerobic fitness is known to alleviate both cognitive and volumetric losses in the brain, it is important to investigate some of the possible mechanisms underlying these beneficial changes. Here we investigated the role that estimated cardiorespiratory fitness (eCRF) plays in determining the relationship between aging and cerebral blood flow (CBF) in a group of older adults (ages 55–85). Using arterial spin labeling to quantify CBF, we found that blood flow in the gray matter was positively correlated with eCRF and negatively correlated with age. Subsequent analyses revealed that eCRF fully mediated the effects of age on CBF in the gray matter, but not in the white matter. Additionally, regional measures of CBF were related to regional measures of brain volume. These findings provide evidence that age-related effects on cerebrovascular health and perfusion in older adults are largely influenced by their eCRF levels. PMID:24778617

  4. Combination 3D TOP with 2D PC MRA Techique for cerebral blood flow volume measurement.

    PubMed

    Guo, G; Wu, R H; Zhang, Y P; Guan, J T; Guo, Y L; Cheng, Y; terBrugge, K; Mikulis, D J

    2006-01-01

    To demonstrate the discrepancy of cerebral blood flow volume (BFV) estimation with 2D phase-contrast (2D PC) MRA guided with 3D time-of-flight (3D TOF) MR localization by using an "internal" standard. 20 groups of the common (CCA), internal (ICA), and external (ECA) carotid arteries in 10 healthy subjects were examined with 2D PC MRA guided by 3D TOF MR angiograms. The sum BFV of the internal and external carotid arteries was then compared with the ipsilateral common carotid artery flow. An accurate technique would demonstrate no difference. The difference was therefore a measure of accuracy of the method. 3D TOF MRA localization is presented to allow the determination of a slice orientation to improve the accuracy of 2D PC MRA in estimate the BFV. By using the combined protocols, there was better correlation in BFV estimate between the sum of ICA+ECA with the ipsilateral CCA (R2=0.729, P=0.000). The inconsistency (mean +/- SD) was found to be 6.95 +/- 5.95% for estimate the BFV in ICA+ECA and ipsilateral CCA. The main inconsistency was contributed to the ECA and its branches. Guided with 3D TOF MRA localization, 2D PC MRA is more accurate in the determination of blood flow volume in the carotid arteries. PMID:17946401

  5. Beagle puppy model of intraventricular hemorrhage: effect of indomethacin on cerebral blood flow

    SciTech Connect

    Ment, L.R.; Stewart, W.B.; Duncan, C.C.; Scott, D.T.; Lambrecht, R.

    1983-06-01

    The newborn beagle puppy has been demonstrated to provide a good model for neonatal intraventricular hemorrhage (IVH). A study was designed to determine if indomethacin can prevent IVH and if indomethacin would produce changes in cerebral blood flow (CBF). Newborn beagle puppies were randomized by computer into two groups: one was pretreated with indomethacin, a known inhibitor of prostaglandin synthetase, and the other was saline. The dogs in both groups were then assigned either to undergo hemorrhagic hypotension/volume reexpansion insult or to receive no insult. Twenty percent of all pups receiving indomethacin and undergoing the insult experienced IVH, compared to 71% of the pups undergoing insult that had been pretreated with saline. Significant alterations in the blood pressure responses to the hemorrhagic hypotension/volume reexpansion insult were noted in the former group compared to the saline-pretreated pups subjected to insult. Finally, employing carbon-14 autoradiography for the determination of CBF, it was demonstrated that indomethacin decreases resting CBF of the newborn beagle pups and, in indomethacin-pretreated animals subjected to insult, prevents the increases in CBF seen in the saline-pretreated traumatized pups. 62 references, 1 figure, 3 tables.

  6. Imaging of Cerebral Blood Flow in Patients with Severe Traumatic Brain Injury in the Neurointensive Care

    PubMed Central

    Rostami, Elham; Engquist, Henrik; Enblad, Per

    2014-01-01

    Ischemia is a common and deleterious secondary injury following traumatic brain injury (TBI). A great challenge for the treatment of TBI patients in the neurointensive care unit (NICU) is to detect early signs of ischemia in order to prevent further advancement and deterioration of the brain tissue. Today, several imaging techniques are available to monitor cerebral blood flow (CBF) in the injured brain such as positron emission tomography (PET), single-photon emission computed tomography, xenon computed tomography (Xenon-CT), perfusion-weighted magnetic resonance imaging (MRI), and CT perfusion scan. An ideal imaging technique would enable continuous non-invasive measurement of blood flow and metabolism across the whole brain. Unfortunately, no current imaging method meets all these criteria. These techniques offer snapshots of the CBF. MRI may also provide some information about the metabolic state of the brain. PET provides images with high resolution and quantitative measurements of CBF and metabolism; however, it is a complex and costly method limited to few TBI centers. All of these methods except mobile Xenon-CT require transfer of TBI patients to the radiological department. Mobile Xenon-CT emerges as a feasible technique to monitor CBF in the NICU, with lower risk of adverse effects. Promising results have been demonstrated with Xenon-CT in predicting outcome in TBI patients. This review covers available imaging methods used to monitor CBF in patients with severe TBI. PMID:25071702

  7. Chronic whiplash symptoms are related to altered regional cerebral blood flow in the resting state.

    PubMed

    Linnman, Clas; Appel, Lieuwe; Söderlund, Anne; Frans, Orjan; Engler, Henry; Furmark, Tomas; Gordh, Torsten; Långström, Bengt; Fredrikson, Mats

    2009-01-01

    The neural pathogenic mechanisms involved in mediating chronic pain and whiplash associated disorders (WAD) after rear impact car collisions are largely unknown. This study's first objective was to compare resting state regional cerebral blood flow (rCBF) by means of positron emission tomography with (15)O labelled water in 21 WAD patients with 18 healthy, pain-free controls. A second objective was to investigate the relations between brain areas with altered rCBF to pain experience, somatic symptoms, posttraumatic stress symptoms and personality traits in the patient group. Patients had heightened resting rCBF bilaterally in the posterior parahippocampal and the posterior cingulate gyri, in the right thalamus and the right medial prefrontal gyrus as well as lowered tempero-occipital blood flow compared with healthy controls. The altered rCBF in the patient group was correlated to neck disability ratings. We thus suggest an involvement of the posterior cingulate, parahippocampal and medial prefrontal gyri in WAD and speculate that alterations in the resting state are linked to an increased self-relevant evaluation of pain and stress. PMID:18486506

  8. Cerebral blood oxygenation measurement based on oxygen-dependent quenching of phosphorescence.

    PubMed

    Sakadžić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A; Mandeville, Emiri T; Srinivasan, Vivek J; Arai, Ken; Ruvinskaya, Svetlana; Wu, Weicheng; Devor, Anna; Lo, Eng H; Vinogradov, Sergei A; Boas, David A

    2011-01-01

    Monitoring of the spatiotemporal characteristics of cerebral blood and tissue oxygenation is crucial for better understanding of the neuro-metabolic-vascular relationship. Development of new pO2 measurement modalities with simultaneous monitoring of pO2 in larger fields of view with higher spatial and/or temporal resolution will enable greater insight into the functioning of the normal brain and will also have significant impact on diagnosis and treatment of neurovascular diseases such as stroke, Alzheimer's disease, and head injury. Optical imaging modalities have shown a great potential to provide high spatiotemporal resolution and quantitative imaging of pO2 based on hemoglobin absorption in visible and near infrared range of optical spectrum. However, multispectral measurement of cerebral blood oxygenation relies on photon migration through the highly scattering brain tissue. Estimation and modeling of tissue optical parameters, which may undergo dynamic changes during the experiment, is typically required for accurate estimation of blood oxygenation. On the other hand, estimation of the partial pressure of oxygen (pO2) based on oxygen-dependent quenching of phosphorescence should not be significantly affected by the changes in the optical parameters of the tissue and provides an absolute measure of pO2. Experimental systems that utilize oxygen-sensitive dyes have been demonstrated in in vivo studies of the perfused tissue as well as for monitoring the oxygen content in tissue cultures, showing that phosphorescence quenching is a potent technology capable of accurate oxygen imaging in the physiological pO2 range. Here we demonstrate with two different imaging modalities how to perform measurement of pO2 in cortical vasculature based on phosphorescence lifetime imaging. In first demonstration we present wide field of view imaging of pO2 at the cortical surface of a rat. This imaging modality has relatively simple experimental setup based on a CCD camera and a

  9. Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence

    PubMed Central

    Sakadžić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A.; Mandeville, Emiri T.; Srinivasan, Vivek J.; Arai, Ken; Ruvinskaya, Svetlana; Wu, Weicheng; Devor, Anna; Lo, Eng H.; Vinogradov, Sergei A.; Boas, David A.

    2011-01-01

    Monitoring of the spatiotemporal characteristics of cerebral blood and tissue oxygenation is crucial for better understanding of the neuro-metabolic-vascular relationship. Development of new pO2 measurement modalities with simultaneous monitoring of pO2 in larger fields of view with higher spatial and/or temporal resolution will enable greater insight into the functioning of the normal brain and will also have significant impact on diagnosis and treatment of neurovascular diseases such as stroke, Alzheimer's disease, and head injury. Optical imaging modalities have shown a great potential to provide high spatiotemporal resolution and quantitative imaging of pO2 based on hemoglobin absorption in visible and near infrared range of optical spectrum. However, multispectral measurement of cerebral blood oxygenation relies on photon migration through the highly scattering brain tissue. Estimation and modeling of tissue optical parameters, which may undergo dynamic changes during the experiment, is typically required for accurate estimation of blood oxygenation. On the other hand, estimation of the partial pressure of oxygen (pO2) based on oxygen-dependent quenching of phosphorescence should not be significantly affected by the changes in the optical parameters of the tissue and provides an absolute measure of pO2. Experimental systems that utilize oxygen-sensitive dyes have been demonstrated in in vivo studies of the perfused tissue as well as for monitoring the oxygen content in tissue cultures, showing that phosphorescence quenching is a potent technology capable of accurate oxygen imaging in the physiological pO2 range. Here we demonstrate with two different imaging modalities how to perform measurement of pO2 in cortical vasculature based on phosphorescence lifetime imaging. In first demonstration we present wide field of view imaging of pO2 at the cortical surface of a rat. This imaging modality has relatively simple experimental setup based on a CCD camera and a

  10. Extrarenal abnormalities in Tc-99m-DTPA renal blood flow studies

    SciTech Connect

    Shih, W.J.; Domstad, P.A.; DeLand, F.H.

    1985-01-01

    The authors observed extrarenal abnormalities during renal flow scintigraphy and retrospectively reviewed 90 patient studies to determine the types and frequencies of such abnormal findings. For each routine Tc-99m-DTPA renal flow study, they obtained nine 2-second sequential images, which included the heart, abdominal aorta, spleen and kidneys. Eighty abnormalities, observed in 62 patients, were divided into three categories: aortic, 37 cases; splenic, 40 cases; and miscellaneous, 3 cases. Other correlative studies including Tc-99m sulfur colloid-spleen scintigraphy, ultrasonography (US), CT, aortography, and surgical and/or autopsy findings were available for corroboration in 56 of 80 lesions.

  11. The paper punched disc technique for lead in blood samples with abnormal haemoglobin values.

    PubMed Central

    Carter, G F

    1978-01-01

    A series of 15 blood samples with haemoglobin levels ranging from 4-6--16-1 g/dl were spotted on to Whatman No. 4 filter paper. Blood samples with low haemoglobin concentrations spread over a greater area of the filter paper than did those with high haemoglobin concentrations. This was further investigated by studying the performance of laboratory-prepared samples, and any effect on the estimation of blood lead value. Blood lead values assayed by the punched disc method on blood samples with low haemoglobin values were unreliable unless the estimated value was adjusted with respect to the area over which the blood had spread. Images PMID:698139

  12. Feasibility of Quantifying Arterial Cerebral Blood Volume Using Multiphase Alternate Ascending/Descending Directional Navigation (ALADDIN)

    PubMed Central

    Kim, Ki Hwan; Choi, Seung Hong; Park, Sung-Hong

    2016-01-01

    Arterial cerebral blood volume (aCBV) is associated with many physiologic and pathologic conditions. Recently, multiphase balanced steady state free precession (bSSFP) readout was introduced to measure labeled blood signals in the arterial compartment, based on the fact that signal difference between labeled and unlabeled blood decreases with the number of RF pulses that is affected by blood velocity. In this study, we evaluated the feasibility of a new 2D inter-slice bSSFP-based arterial spin labeling (ASL) technique termed, alternate ascending/descending directional navigation (ALADDIN), to quantify aCBV using multiphase acquisition in six healthy subjects. A new kinetic model considering bSSFP RF perturbations was proposed to describe the multiphase data and thus to quantify aCBV. Since the inter-slice time delay (TD) and gap affected the distribution of labeled blood spins in the arterial and tissue compartments, we performed the experiments with two TDs (0 and 500 ms) and two gaps (300% and 450% of slice thickness) to evaluate their roles in quantifying aCBV. Comparison studies using our technique and an existing method termed arterial volume using arterial spin tagging (AVAST) were also separately performed in five subjects. At 300% gap or 500-ms TD, significant tissue perfusion signals were demonstrated, while tissue perfusion signals were minimized and arterial signals were maximized at 450% gap and 0-ms TD. ALADDIN has an advantage of visualizing bi-directional flow effects (ascending/descending) in a single experiment. Labeling efficiency (α) of inter-slice blood flow effects could be measured in the superior sagittal sinus (SSS) (20.8±3.7%.) and was used for aCBV quantification. As a result of fitting to the proposed model, aCBV values in gray matter (1.4–2.3 mL/100 mL) were in good agreement with those from literature. Our technique showed high correlation with AVAST, especially when arterial signals were accentuated (i.e., when TD = 0 ms) (r = 0

  13. Feasibility of Quantifying Arterial Cerebral Blood Volume Using Multiphase Alternate Ascending/Descending Directional Navigation (ALADDIN).

    PubMed

    Kim, Ki Hwan; Choi, Seung Hong; Park, Sung-Hong

    2016-01-01

    Arterial cerebral blood volume (aCBV) is associated with many physiologic and pathologic conditions. Recently, multiphase balanced steady state free precession (bSSFP) readout was introduced to measure labeled blood signals in the arterial compartment, based on the fact that signal difference between labeled and unlabeled blood decreases with the number of RF pulses that is affected by blood velocity. In this study, we evaluated the feasibility of a new 2D inter-slice bSSFP-based arterial spin labeling (ASL) technique termed, alternate ascending/descending directional navigation (ALADDIN), to quantify aCBV using multiphase acquisition in six healthy subjects. A new kinetic model considering bSSFP RF perturbations was proposed to describe the multiphase data and thus to quantify aCBV. Since the inter-slice time delay (TD) and gap affected the distribution of labeled blood spins in the arterial and tissue compartments, we performed the experiments with two TDs (0 and 500 ms) and two gaps (300% and 450% of slice thickness) to evaluate their roles in quantifying aCBV. Comparison studies using our technique and an existing method termed arterial volume using arterial spin tagging (AVAST) were also separately performed in five subjects. At 300% gap or 500-ms TD, significant tissue perfusion signals were demonstrated, while tissue perfusion signals were minimized and arterial signals were maximized at 450% gap and 0-ms TD. ALADDIN has an advantage of visualizing bi-directional flow effects (ascending/descending) in a single experiment. Labeling efficiency (α) of inter-slice blood flow effects could be measured in the superior sagittal sinus (SSS) (20.8±3.7%.) and was used for aCBV quantification. As a result of fitting to the proposed model, aCBV values in gray matter (1.4-2.3 mL/100 mL) were in good agreement with those from literature. Our technique showed high correlation with AVAST, especially when arterial signals were accentuated (i.e., when TD = 0 ms) (r = 0

  14. Hemodynamics of Cerebral Aneurysms

    PubMed Central

    Sforza, Daniel M.; Putman, Christopher M.; Cebral, Juan Raul

    2009-01-01

    The initiation and progression of cerebral aneurysms are degenerative processes of the arterial wall driven by a complex interaction of biological and hemodynamic factors. Endothelial cells on the artery wall respond physiologically to blood-flow patterns. In normal conditions, these responses are associated with nonpathological tissue remodeling and adaptation. The combination of abnormal blood patterns and genetics predisposition could lead to the pathological formation of aneurysms. Here, we review recent progress on the basic mechanisms of aneurysm formation and evolution, with a focus on the role of hemodynamic patterns. PMID:19784385

  15. Arterial input function and gray matter cerebral blood volume measurements in children

    PubMed Central

    Withey, Stephanie B.; Novak, Jan; MacPherson, Lesley

    2015-01-01

    Purpose To investigate how arterial input functions (AIFs) vary with age in children and compare the use of individual and population AIFs for calculating gray matter CBV values. Quantitative measures of cerebral blood volume (CBV) using dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) require measurement of an AIF. AIFs are affected by numerous factors including patient age. Few data presenting AIFs in the pediatric population exists. Materials and Methods Twenty‐two previously treated pediatric brain tumor patients (mean age, 6.3 years; range, 2.0–15.3 years) underwent DSC‐MRI scans on a 3T MRI scanner over 36 visits. AIFs were measured in the middle cerebral artery. A functional form of an adult population AIF was fitted to each AIF to obtain parameters reflecting AIF shape. The relationship between parameters and age was assessed. Correlations between gray matter CBV values calculated using the resulting population and individual patient AIFs were explored. Results There was a large variation in individual patient AIFs but correlations between AIF shape and age were observed. The center (r = 0.596, P < 0.001) and width of the first‐pass peak (r = 0.441, P = 0.007) were found to correlate significantly with age. Intrapatient coefficients of variation were significantly lower than interpatient values for all parameters (P < 0.001). Differences in CBV values calculated with an overall population and age‐specific population AIF compared to those calculated with individual AIFs were 31.3% and 31.0%, respectively. Conclusion Parameters describing AIF shape correlate with patient age in line with expected changes in cardiac output. In pediatric DSC‐MRI studies individual patient AIFs are recommended. J. Magn. Reson. Imaging 2016;43:981–989 PMID:26514288

  16. Regional cerebral blood flow and FDG uptake in asymptomatic HIV-1 men.

    PubMed

    Towgood, Karen J; Pitkanen, Mervi; Kulasegaram, Ranjababu; Fradera, Alex; Soni, Suneeta; Sibtain, Naomi; Reed, Laurence J; Bradbeer, Caroline; Barker, Gareth J; Dunn, Joel T; Zelaya, Fernando; Kopelman, Michael D

    2013-10-01

    Despite advances in the treatment of patients with human immunodeficiency virus (HIV), HIV-associated neurocognitive disorder occurs in 15-50% of HIV-infected individuals, and may become more apparent as ageing advances. In the present study we investigated regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of glucose uptake (rCMRglc) in medically and psychiatrically stable HIV-1-infected participants in two age-groups. Positron emission tomography (PET) and magnetic resonance imaging (MRI)-based arterial spin labeling (ASL) were used to measure rCMRglc and rCBF, respectively, in 35 HIV-infected participants and 37 HIV-negative matched controls. All participants were currently asymptomatic with undetectable HIV-1 viral loads, without medical or psychiatric comorbidity, alcohol or substance misuse, stable on medication for at least 6 months before enrolment in the study. We found significant age effects on both ASL and PET with reduced rCBF and rCMRglc in related frontal brain regions, and consistent, although small, reductions in rCBF and rCMRglc in the anterior cingulate cortex (ACC) in HIV, a finding of potential clinical significance. There was no significant interaction between HIV status and the ageing process, and no significant HIV-related changes elsewhere in the brain on PET or ASL. This is the first paper to combine evidence from ASL and PET method in HIV participants. These finding provide evidence of crossvalidity between the two techniques, both in ageing and a clinical condition (HIV). PMID:22496057

  17. Edaravone increases regional cerebral blood flow after traumatic brain injury in mice.

    PubMed

    Miyamoto, Kazuyuki; Ohtaki, Hirokazu; Dohi, Kenji; Tsumuraya, Tomomi; Nakano, Hiroyasu; Kiriyama, Keisuke; Song, Dandan; Aruga, Tohru; Shioda, Seiji

    2013-01-01

    Traumatic brain injury (TBI) is a major cause of preventable death and serious morbidity, with subsequent low cerebral blood flow (CBF) considered to be associated with poor prognosis. In the present study, we demonstrated the effect of the free radical scavenger edaravone on regional CBF (rCBF) after TBI. Male mice (C57/BL6) were subjected to TBI using a controlled cortical impactor device. Immediately after TBI, the animals were intravenously administered 3.0 mg/kg of edaravone or a vehicle saline solution. Two-dimensional rCBF images were acquired before and 24 h post-TBI, and were quantified in the ipsilateral and contralateral hemispheres (n = 5 animals per group). CBF in the vehicle-treated animals decreased broadly over the ipsilateral hemisphere, with the region of low rCBF spreading from the frontal cortex to the occipital lobe. The zone of lowest rCBF matched that of the contusion area. The mean rCBF at 24 h for a defined elliptical region between the bregma and lambda was 73.7 ± 5.8 %. In comparison, the reduction of rCBF in edaravone-treated animals was significantly attenuated (93.4 ± 5.7 %, p < 0.05). The edaravone-treated animals also exhibited higher rCBF in the contralateral hemisphere compared with that seen in -vehicle-treated animals. It is suggested that edaravone reduces neuronal damage by scavenging reactive oxygen species (ROS) and by maintaining intact the autoregulation of the cerebral vasculature. PMID:23564113

  18. Altered oscillatory cerebral blood flow velocity and autoregulation in postural tachycardia syndrome

    PubMed Central

    Medow, Marvin S.; Del Pozzi, Andrew T.; Messer, Zachary R.; Terilli, Courtney; Stewart, Julian M.

    2014-01-01

    Decreased upright cerebral blood flow (CBF) with hyperpnea and hypocapnia is seen in a minority of patients with postural tachycardia syndrome (POTS). More often, CBF is not decreased despite upright neurocognitive dysfunction. This may result from time-dependent changes in CBF. We hypothesized that increased oscillations in CBF occurs in POTS (N = 12) compared to healthy controls (N = 9), and tested by measuring CBF velocity (CBFv) by transcranial Doppler ultrasound of the middle cerebral artery, mean arterial pressure (MAP) and related parameters, supine and during 70° upright tilt. Autospectra for mean CBFv and MAP, and transfer function analysis were obtained over the frequency range of 0.0078–0.4 Hz. Upright HR was increased in POTS (125 ± 8 vs. 86 ± 2 bpm), as was diastolic BP (74 ± 3 vs. 65 ± 3 mmHg) compared to control, while peripheral resistance, cardiac output, and mean CBFv increased similarly with tilt. Upright BP variability (BPV), low frequency (LF) power (0.04–0.13 Hz), and peak frequency of BPV were increased in POTS (24.3 ± 4.1, and 18.4 ± 4.1 mmHg2/Hz at 0.091 Hz vs. 11.8 ± 3.3, and 8.8 ± 2 mmHg2/Hz c at 0.071 Hz), as was upright overall CBFv variability, low frequency power and peak frequency of CBFv variability (29.3 ± 4.7, and 22.1 ± 2.7 [cm/s]2/Hz at.092 Hz vs. 14.7 ± 2.6, and 6.7 ± 1.2 [cm/s]2/Hz at 0.077Hz). Autospectra were sharply peaked in POTS. LF phase was decreased in POTS (-14 ± 4 vs. -25 ± 10 degrees) while upright. LF gain was increased (1.51 ± 0.09 vs. 0.86 ± 0.12 [cm/s]/ mmHg) while coherence was increased (0.96 ± 0.01 vs. 0.80 ± 0.04). Increased oscillatory BP in upright POTS patients is closely coupled to oscillatory CBFv over a narrow bandwidth corresponding to the Mayer wave frequency. Therefore combined increased oscillatory BP and increased LF gain markedly increases CBFv oscillations in a narrow bandwidth. This close coupling of CBF to MAP indicates impaired cerebral autoregulation that may underlie

  19. Diurnal variation in baseline human regional cerebral blood flow demonstrated by PET

    SciTech Connect

    Diehl, D.J.; Mintun, M.A.; Moore, R.Y.

    1994-05-01

    We have previously described the diurnal variation in regional cerebral blood flow (rCBF) response to bright light in human subjects as demonstrated by the positron emission tomography (PET) activation method. In this abstract, we report the differences in rCBF (an indicator of differences in regional neuronal activity) between the evening and midday dim light baseline scans which served as the control states in the above bright light activation study. Five right-handed, healthy volunteers underwent both an evening (8pm) and a midday (12N) O-15 water PET scanning session. Each scanning session was preceded by one hour of dim light adaptation (50 lux) and consisted of six rCBF scans at three different light intensities in an AABBCC sequence (A=50 lux, B=2500 lux, C=7000lux). Significant differences in rCBF between the evening and midday 50 lux states were identified using the statistical parametric mapping method developed by Friston et al (p<.001). The evening scans demonstrated areas of greater relative blood flow in the pineal gland, the lateral temporal cortex bilaterally, the right lateral prefrontal cortex, the superior aspect of the anterior cingulate, and the left thalamus. The midday scans showed areas of greater relative blood flow in the visual cortex, the left lateral prefrontal cortex. the inferior aspect of the anterior cingulate, the left parietal cortex and the cerebellum. Our results demonstrate an extensive diurnal variation in baseline human rCBF. This indicates that time of day may be an important variable in conducting and interpreting functional brain imaging studies. Furthermore, these results suggest possible neuroanatomical substrates through which the circadian system may regulate the various physiologic and behavioral processes that manifest circadian rhythms.

  20. Cerebral air embolism and subsequent transient neurologic abnormalities in a liver transplant recipient following the removal of the pulmonary artery catheter from the central venous access device: a case report

    PubMed Central

    Kim, Sun-Key; Jun, In-Gu; Jang, Dong-Min; Lim, Jinwook; Hwang, Gyu-Sam

    2016-01-01

    Cerebral air embolism is a rare but potentially life-threatening complication. We experienced a living-donor liver transplant recipient who presented with unexpected cerebral air embolism and transient neurologic abnormalities that subsequently developed just after the removal of the pulmonary artery catheter from the central venous access device. One day after the initial event, the patient's neurologic status gradually improved. The patient was discharged 30 days after liver transplantation without neurologic sequelae. PMID:26885308

  1. Effects of short-term mechanical hyperventilation on cerebral blood flow and dynamic cerebral autoregulation in critically ill patients with sepsis.

    PubMed

    Berg, Ronan M G; Plovsing, Ronni R

    2016-05-01

    In sepsis, higher PaCO2 levels are associated with impaired dynamic cerebral autoregulation (dCA), which may expose the brain to hypo- and hyperperfusion during acute fluctuations in blood pressure. We hypothesised that short-term mechanical hyperventilation would dCA in critically ill patients with sepsis. Seven mechanically ventilated septic patients were included. We assessed dCA before and after 30 min of mechanical hyperventilation. Transfer function analysis of spontaneous oscillations in transcranial Doppler-based middle cerebral artery blood flow velocity (MCAv) and invasive mean arterial blood pressure was used to assess dCA. Mechanical enhance hyperventilation reduced the median PaCO2 from 5.3 (IQR, 5.0-6.5) to 4.7 (IQR, 4.2-5.1) kPa (p < 0.05). This was associated with a reduction in the median MCAv from 57 (IQR, 33-68) to 32 (IQR, 21-40) cm sec(-1) (p < 0.05). Apart from a small increase in gain in the low frequency range (2.32 [IQR 1.80-2.41] vs. 2.59 (2.40-4.64) cm mmHg(-1) sec(-1); p < 0.05), this was not associated with any enhancement in dCA. In conclusion, cerebral CO2 vasoreactivity was found to be preserved in septic patients; nevertheless, and in contrast to our working hypothesis, short-term mechanical hyperventilation did not enhance dCA. PMID:26935607

  2. Ischemic Postconditioning Decreases Cerebral Edema and Brain Blood Barrier Disruption Caused by Relief of Carotid Stenosis in a Rat Model of Cerebral Hypoperfusion

    PubMed Central

    Yang, Fuwei; Zhang, Xiaojie; Sun, Ying; Wang, Boyu; Zhou, Chuibing; Luo, Yinan; Ge, Pengfei

    2013-01-01

    Background and Purpose Complications due to brain edema and breakdown of blood brain barrier are an important factor affecting the treatment effects of patients with severe carotid stenosis. In this study, we investigated the protective effects of ischemic postconditioning on brain edema and disruption of blood brain barrier via establishing rat model of hypoperfusion due to severe carotid stenosis. Methods Wistar rat model of hypoperfusion due to severe carotid stenosis was established by binding a stainless microtube to both carotid arteries. Ischemic postconditioning procedure consisted of three cycles of 30 seconds ischemia and 30 seconds reperfusion. Brain edema was evaluated by measuring cerebral water content, and blood brain barrier permeability was assayed by examining cerebral concentration of Evans' Blue (EB) and fluorescein sodium (NaF). ELISA was used to analyze the expression of MMP-9, claudin-5 and occludin. The activity and location of MMP-9 was analyzed by gelatin zymography and in situ zymography, respectively. The distribution of tight junction proteins claudin-5 and occludin was observed by immunohistochemistry. Results The increased brain water content and cerebral concentration of EB and NaF were suppressed by administration of ischemic postconditioning prior to relief of carotid stenosis. Zymographic studies showed that MMP-9 was mainly located in the cortex and its activity was significantly improved by relief of carotid stenosis and, but the elevated MMP-9 activity was inhibited markedly by ischemic postconditioning. Immunohistochemistry revealed that ischemic postconditioning improved the discontinuous distribution of claudin-5 and occludin. ELISA detected that the expression of up-regulated MMP-9 and down-regulated claudin-5 and occludin caused by carotid relief were all attenuated by ischemic postconditioning. Conclusions Ischemic postconditioning is an effective method to prevent brain edema and improve BBB permeability and could be

  3. Soluble epoxide hydrolase gene deletion improves blood flow and reduces infarct size after cerebral ischemia in reproductively senescent female mice

    PubMed Central

    Zuloaga, Kristen L.; Zhang, Wenri; Roese, Natalie E.; Alkayed, Nabil J.

    2015-01-01

    Soluble epoxide hydrolase (sEH), a key enzyme in the metabolism of vasodilatory epoxyeicosatrienoic acids (EETs), is sexually dimorphic, suppressed by estrogen, and contributes to underlying sex differences in cerebral blood flow and injury after cerebral ischemia. We tested the hypothesis that sEH inhibition or gene deletion in reproductively senescent (RS) female mice would increase cerebral perfusion and decrease infarct size following stroke. RS (15–18 month old) and young (3–4 month old) female sEH knockout (sEHKO) mice and wild type (WT) mice were subjected to 45 min middle cerebral artery occlusion (MCAO) with laser Doppler perfusion monitoring. WT mice were treated with vehicle or a sEH inhibitor t-AUCB at the time of reperfusion and every 24 h thereafter for 3 days. Differences in regional cerebral blood flow were measured in vivo using optical microangiography (OMAG). Infarct size was measured 3 days after reperfusion. Infarct size and cerebral perfusion 24 h after MCAO were not altered by age. Both sEH gene deletion and sEH inhibition increased cortical perfusion 24 h after MCAO. Neither sEH gene deletion nor sEH inhibition reduced infarct size in young mice. However, sEH gene deletion, but not sEH inhibition of the hydrolase domain of the enzyme, decreased infarct size in RS mice. Results of these studies show that sEH gene deletion and sEH inhibition enhance cortical perfusion following MCAO and sEH gene deletion reduces damage after ischemia in RS female mice; however this neuroprotection in absent is young mice. PMID:25642188

  4. Cerebralcare Granule® attenuates blood-brain barrier disruption after middle cerebral artery occlusion in rats.

    PubMed

    Huang, Ping; Zhou, Chang-Man; Qin-Hu; Liu, Yu-Ying; Hu, Bai-He; Chang, Xin; Zhao, Xin-Rong; Xu, Xiang-Shun; Li, Quan; Wei, Xiao-Hong; Mao, Xiao-Wei; Wang, Chuan-She; Fan, Jing-Yu; Han, Jing-Yan

    2012-10-01

    Disruption of blood-brain barrier (BBB) and subsequent edema are major contributors to the pathogenesis of ischemic stroke, for which the current clinical therapy remains unsatisfied. Cerebralcare Granule® (CG) is a compound Chinese medicine widely used in China for treatment of cerebrovascular diseases. CG has been demonstrated efficacy in attenuating the cerebral microcirculatory disturbance and hippocampal neuron injury following global cerebral ischemia. However, the effects of CG on BBB disruption following cerebral ischemia have not been investigated. In this study, we examined the therapeutic effect of CG on the BBB disruption in a focal cerebral ischemia/reperfusion (I/R) rat model. Male Sprague-Dawley rats (250 to 300 g) were subjected to 1h middle cerebral artery occlusion (MCAO). CG (0.4 g/kg or 0.8 g/kg) was administrated orally 3h after reperfusion for the first time and then once daily up to 6 days. The results showed that Evans blue extravasation, brain water content, albumin leakage, infarction volume and neurological deficits increased in MCAO model rats, and were attenuated significantly by CG treatment. T2-weighted MRI and electron microscopy further confirmed the brain edema reduction in CG-treated rats. Treatment with CG improved cerebral blood flow (CBF). Western blot analysis and confocal microscopy showed that the tight junction proteins claudin-5, JAM-1, occludin and zonula occluden-1 between endothelial cells were significantly degradated, but the protein expression of caveolin-1, the principal marker of caveolae in endothelial cells, increased after ischemia, all of which were alleviated by CG treatment. In conclusion, the post-treatment with CG significantly reduced BBB permeability and brain edema, which were correlated with preventing the degradation of the tight junction proteins and inhibiting the expression of caveolin-1 in the endothelial cells. These findings provide a novel approach to the treatment of ischemic stroke. PMID

  5. Inhibition of cerebrovascular raf activation attenuates cerebral blood flow and prevents upregulation of contractile receptors after subarachnoid hemorrhage

    PubMed Central

    2011-01-01

    Background Late cerebral ischemia carries high morbidity and mortality after subarachnoid hemorrhage (SAH) due to reduced cerebral blood flow (CBF) and the subsequent cerebral ischemia which is associated with upregulation of contractile receptors in the vascular smooth muscle cells (SMC) via activation of mitogen-activated protein kinase (MAPK) of the extracellular signal-regulated kinase (ERK)1/2 signal pathway. We hypothesize that SAH initiates cerebrovascular ERK1/2 activation, resulting in receptor upregulation. The raf inhibitor will inhibit the molecular events upstream ERK1/2 and may provide a therapeutic window for treatment of cerebral ischemia after SAH. Results Here we demonstrate that SAH increases the phosphorylation level of ERK1/2 in cerebral vessels and reduces the neurology score in rats in additional with the CBF measured by an autoradiographic method. The intracisternal administration of SB-386023-b, a specific inhibitor of raf, given 6 h after SAH, aborts the receptor changes and protects the brain from the development of late cerebral ischemia at 48 h. This is accompanied by reduced phosphorylation of ERK1/2 in cerebrovascular SMC. SAH per se enhances contractile responses to endothelin-1 (ET-1), 5-carboxamidotryptamine (5-CT) and angiotensin II (Ang II), upregulates ETB, 5-HT1B and AT1 receptor mRNA and protein levels. Treatment with SB-386023-b given as late as at 6 h but not at 12 h after the SAH significantly decreased the receptor upregulation, the reduction in CBF and the neurology score. Conclusion These results provide evidence for a role of the ERK1/2 pathway in regulation of expression of cerebrovascular SMC receptors. It is suggested that raf inhibition may reduce late cerebral ischemia after SAH and provides a realistic time window for therapy. PMID:22032648

  6. The effect of the nitric oxide donor glyceryl trinitrate on global and regional cerebral blood flow in man.

    PubMed

    White, R P; Deane, C; Hindley, C; Bloomfield, P M; Cunningham, V J; Vallance, P; Brooks, D J; Markus, H S

    2000-09-01

    Despite their potential use as cerebral vasodilatory agents there are few studies of the effect of nitric oxide (NO) donors on the cerebral circulation in non-anaesthetised man. We determined the effect of the NO donor glyceryl trinitrate (GTN) at clinically relevant doses on global and regional cerebral blood flow (CBF) in healthy non-anaesthetised volunteers, using H(2)(15)O PET, ultrasonic colour velocity flow imaging of carotid artery flow, and transcranial Doppler (TCD) of middle cerebral artery velocities (MCAv). Three rates of GTN infusion (0.1, 0.4, 1.0 microg/kg/min) were used. There was no significant change in common or internal carotid artery flow following GTN administration although a dose dependent fall in MCAv post GTN was observed. There was no significant change in either global or regional CBF following GTN. Thus intravenous GTN at therapeutic doses in awake humans does not alter global or regional CBF. However it does produce basal cerebral artery vasodilatation as evidenced by a fall in MCAv in the absence of a change in internal carotid artery flow. PMID:11018245

  7. Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude.

    PubMed

    Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

    2016-01-01

    To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (-17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution. PMID:27503416

  8. Blood-Spinal Cord Barrier Alterations in Subacute and Chronic Stages of a Rat Model of Focal Cerebral Ischemia.

    PubMed

    Garbuzova-Davis, Svitlana; Haller, Edward; Tajiri, Naoki; Thomson, Avery; Barretta, Jennifer; Williams, Stephanie N; Haim, Eithan D; Qin, Hua; Frisina-Deyo, Aric; Abraham, Jerry V; Sanberg, Paul R; Van Loveren, Harry; Borlongan, Cesario V

    2016-07-01

    We previously demonstrated blood-brain barrier impairment in remote contralateral brain areas in rats at 7 and 30 days after transient middle cerebral artery occlusion (tMCAO), indicating ischemic diaschisis. Here, we focused on effects of subacute and chronic focal cerebral ischemia on the blood-spinal cord barrier (BSCB). We observed BSCB damage on both sides of the cervical spinal cord in rats at 7 and 30 days post-tMCAO. Major BSCB ultrastructural changes in spinal cord gray and white matter included vacuolated endothelial cells containing autophagosomes, pericyte degeneration with enlarged mitochondria, astrocyte end-feet degeneration and perivascular edema; damaged motor neurons, swollen axons with unraveled myelin in ascending and descending tracts and astrogliosis were also observed. Evans Blue dye extravasation was maximal at 7 days. There was immunofluorescence evidence of reduction of microvascular expression of tight junction occludin, upregulation of Beclin-1 and LC3B immunoreactivities at 7 days and a reduction of the latter at 30 days post-ischemia. These novel pathological alterations on the cervical spinal cord microvasculature in rats after tMCAO suggest pervasive and long-lasting BSCB damage after focal cerebral ischemia, and that spinal cord ischemic diaschisis should be considered in the pathophysiology and therapeutic approaches in patients with ischemic cerebral infarction. PMID:27283328

  9. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    NASA Astrophysics Data System (ADS)

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-05-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome.

  10. Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

    2016-08-01

    To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (‑17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.

  11. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage.

    PubMed

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P Ellen; Franceschini, Maria Angela

    2016-01-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant's bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome. PMID:27181339

  12. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    PubMed Central

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-01-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome. PMID:27181339

  13. Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

    PubMed Central

    Liu, Jie; Liu, Yang; Ren, Li-hua; Li, Li; Wang, Zhen; Liu, Shan-shan; Li, Su-zhi; Cao, Tie-sheng

    2016-01-01

    To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (−17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution. PMID:27503416

  14. Congenital Abnormalities

    MedlinePlus

    ... serious health problems (e.g. Down syndrome ). Single-Gene Abnormalities Sometimes the chromosomes are normal in number, ... blood flow to the fetus impair fetal growth. Alcohol consumption and certain drugs during pregnancy significantly increase ...

  15. Peripheral Blood and Bone Marrow Abnormalities in the Acquired Immunodeficiency Syndrome

    PubMed Central

    Frontiera, Michael; Myers, Adam M.

    1987-01-01

    In reviewing the peripheral hematologic manifestations, bone marrow changes and clinical course in 41 consecutive patients with acquired immunodeficiency syndrome (AIDS), frequent findings included anemia (95%), leukopenia (76%), bone marrow hypercellularity (73%) and pancytopenia (41%). These hematologic abnormalities were not clearly associated with specific clinical manifestations of AIDS, but support the conclusion that the hematopoietic system is a target organ in AIDS. The mechanisms of these abnormalities still need to be evaluated. Clinicians should be aware of these commonly encountered changes. Images PMID:3660772

  16. Abnormal regional blood flow responses during and after exercise in human sympathetic denervation.

    PubMed Central

    Puvi-Rajasingham, S; Smith, G D; Akinola, A; Mathias, C J

    1997-01-01

    1. Blood pressure, superior mesenteric artery (SMA) and skeletal muscle blood flow, cardiac index (CI) and systemic vascular resistance responses to supine leg exercise were measured in six age-matched normal subjects (controls) and in eleven subjects with sympathetic denervation due to primary autonomic failure (AF). 2. During exercise, blood pressure rose in controls but fell markedly in AF. After exercise, blood pressure rapidly returned to baseline in controls but remained low in AF. During exercise, systemic vascular resistance fell in controls and AF but tended to fall further in AF and remained low post exercise. CI increased similarly in controls and AF. 3. During exercise, SMA blood flow fell similarly in controls and AF, but the fall initially was slower in AF; recovery was more rapid post exercise in controls. SMA vascular resistance tended to rise less and more slowly in AF and remained elevated post exercise. 4. Forearm muscle (FM) blood flow and FM vascular resistance did not change from resting values in controls or AF post exercise. After exercise, leg muscle (LM) blood flow rose and LM vascular resistance fell equally in both groups although LM blood flow remained elevated, 10 min post exercise in AF. 5. In sympathetically denervated humans, increased blood flow (due to excessive vasodilatation, lack of sympathetic restraint, or both) in leg muscle during and after exercise in combination with impaired splanchnic vasoconstriction in the early stages of exercise may have contributed to exercise-induced hypotension. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:9457657

  17. Reconciling paradigms of abnormal pulmonary blood flow and quasi-malignant cellular alterations in pulmonary arterial hypertension.

    PubMed

    Happé, C M; Szulcek, R; Voelkel, N F; Bogaard, H J

    2016-08-01

    In pulmonary arterial hypertension (PAH) structural and functional abnormalities of the small lung vessels interact and lead to a progressive increase in pulmonary vascular resistance and right heart failure. A current pathobiological concept characterizes PAH as a 'quasi-malignant' disease focusing on cancer-like alterations in endothelial cells (EC) and the importance of their acquired apoptosis-resistant, hyper-proliferative phenotype in the process of vascular remodeling. While changes in pulmonary blood flow (PBF) have been long-since recognized and linked to the development of PAH, little is known about a possible relationship between an altered PBF and the quasi-malignant cell phenotype in the pulmonary vascular wall. This review summarizes recognized and hypothetical effects of an abnormal PBF on the pulmonary vascular bed and links these to quasi-malignant changes found in the pulmonary endothelium. Here we describe that abnormal PBF does not only trigger a pulmonary vascular cell growth program, but may also maintain the cancer-like phenotype of the endothelium. Consequently, normalization of PBF and EC response to abnormal PBF may represent a treatment strategy in patients with established PAH. PMID:26804008

  18. Potential of optical microangiography to monitor cerebral blood perfusion and vascular plasticity following traumatic brain injury in mice in vivo

    NASA Astrophysics Data System (ADS)

    Jia, Yali; Alkayed, Nabil; Wang, Ruikang K.

    2009-07-01

    Optical microanglography (OMAG) is a recently developed imaging modality capable of volumetric imaging of dynamic blood perfusion, down to capillary level resolution, with an imaging depth up to 2.00 mm beneath the tissue surface. We report the use of OMAG to monitor the cerebral blood flow (CBF) over the cortex of mouse brain upon traumatic brain injury (TBI), with the cranium left intact, for a period of two weeks on the same animal. We show the ability of OMAG to repeatedly image 3-D cerebral vasculatures during pre- and post-traumatic phases, and to visualize the changes of regulated CBF and the vascular plasticity after TBI. The results indicate the potential of OMAG to explore the mechanism involved in the rehabilitation of TBI.

  19. Simultaneous automatic arteries-veins separation and cerebral blood flow imaging with single-wavelength laser speckle imaging

    NASA Astrophysics Data System (ADS)

    Feng, Nengyun; Qiu, Jianjun; Li, Pengcheng; Sun, Xiaoli; Yin, Cui; Luo, Weihua; Chen, Shangbin; Luo, Qingming

    2011-08-01

    Automatic separation of arteries and veins in optical cerebral cortex images is important in clinical practice and preclinical study. In this paper, a simple but effective automatic artery-vein separation method which utilizes single-wavelength coherent illumination is presented. This method is based on the relative temporal minimum reflectance analysis of laser speckle images. The validation is demonstrated with both theoretic simulations and experimental results applied to the rat cortex. Moreover, this method can be combined with laser speckle contrast analysis so that the artery-vein separation and blood flow imaging can be simultaneously obtained using the same raw laser speckle images data to enable more accurate analysis of changes of cerebral blood flow within different tissue compartments during functional activation, disease dynamic, and neurosurgery, which may broaden the applications of laser speckle imaging in biology and medicine.

  20. Quantitative local cerebral blood flow measurements with technetium-99m HM-PAO: evaluation using multiple radionuclide digital quantitative autoradiography

    SciTech Connect

    Lear, J.L.

    1988-08-01

    We investigated d,1 (/sup 99m/Tc)hexamethylpropyleneamine oxime complex (HM-PAO) as a tracer for quantitative measurement of local cerebral blood flow (LCBF) in a series of awake male rats. LCBF measurements with HM-PAO were compared to those of two other tracers, (/sup 14/C) iodoantipyrine (IAP) and (/sup 201/Tl)diethyldithiocarbamate (DDC), using quantitative double and triple tracer digital autoradiography. LCBF values with HM-PAO averaged 64% those of IAP and were generally linearly related. Detailed analysis suggested that the underestimation of LCBF by HM-PAO was related to blood constituent binding and/or rapid conversion to a noncerebrophilic compound, as well as noninstantaneous cerebral trapping, rather than to diffusion limitation.

  1. Relationship of spikes, synaptic activity, and local changes of cerebral blood flow.

    PubMed

    Lauritzen, M

    2001-12-01

    The coupling of electrical activity in the brain to changes in cerebral blood flow (CBF) is of interest because hemodynamic changes are used to track brain function. Recent studies, especially those investigating the cerebellar cortex, have shown that the spike rate in the principal target cell of a brain region (i.e. the efferent cell) does not affect vascular response amplitude. Subthreshold integrative synaptic processes trigger changes in the local microcirculation and local glucose consumption. The spatial specificity of the vascular response on the brain surface is limited because of the functional anatomy of the pial vessels. Within the cortex there is a characteristic laminar flow distribution, the largest changes of which are observed at the depth of maximal synaptic activity (i.e. layer IV) for an afferent input system. Under most conditions, increases in CBF are explained by activity in postsynaptic neurons, but presynaptic elements can contribute. Neurotransmitters do not mediate increases in CBF that are triggered by the concerted action of several second messenger molecules. It is important to distinguish between effective synaptic inhibition and deactivation that increase and decrease CBF and glucose consumption, respectively. In summary, hemodynamic changes evoked by neuronal activity depend on the afferent input function (i.e. all aspects of presynaptic and postsynaptic processing), but are totally independent of the efferent function (i.e., the spike rate of the same region). Thus, it is not possible to conclude whether the output level of activity of a region is increased based on brain maps that use blood-flow changes as markers. PMID:11740198

  2. Hippocampal and Cerebral Blood Flow after Exercise Cessation in Master Athletes

    PubMed Central

    Alfini, Alfonso J.; Weiss, Lauren R.; Leitner, Brooks P.; Smith, Theresa J.; Hagberg, James M.; Smith, J. Carson

    2016-01-01

    While endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus, the effects of stopping this exercise on the brain remain unclear. Our aim was to measure the effects of 10 days of detraining on resting cerebral blood flow (rCBF) in gray matter and the hippocampus in healthy and physically fit older adults. We hypothesized that rCBF would decrease in the hippocampus after a 10-day cessation of exercise training. Twelve master athletes, defined as older adults (age ≥ 50 years) with long-term endurance training histories (≥15 years), were recruited from local running clubs. After screening, eligible participants were asked to cease all training and vigorous physical activity for 10 consecutive days. Before and immediately after the exercise cessation period, rCBF was measured with perfusion-weighted MRI. A voxel-wise analysis was used in gray matter, and the hippocampus was selected a priori as a structurally defined region of interest (ROI), to detect rCBF changes over time. Resting CBF significantly decreased in eight gray matter brain regions. These regions included: (L) inferior temporal gyrus, fusiform gyrus, inferior parietal lobule, (R) cerebellar tonsil, lingual gyrus, precuneus, and bilateral cerebellum (FWE p < 0.05). Additionally, rCBF within the left and right hippocampus significantly decreased after 10 days of no exercise training. These findings suggest that the cerebrovascular system, including the regulation of resting hippocampal blood flow, is responsive to short-term decreases in exercise training among master athletes. Cessation of exercise training among physically fit individuals may provide a novel method to assess the effects of acute exercise and exercise training on brain function in older adults. PMID:27547184

  3. Hippocampal and Cerebral Blood Flow after Exercise Cessation in Master Athletes.

    PubMed

    Alfini, Alfonso J; Weiss, Lauren R; Leitner, Brooks P; Smith, Theresa J; Hagberg, James M; Smith, J Carson

    2016-01-01

    While endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus, the effects of stopping this exercise on the brain remain unclear. Our aim was to measure the effects of 10 days of detraining on resting cerebral blood flow (rCBF) in gray matter and the hippocampus in healthy and physically fit older adults. We hypothesized that rCBF would decrease in the hippocampus after a 10-day cessation of exercise training. Twelve master athletes, defined as older adults (age ≥ 50 years) with long-term endurance training histories (≥15 years), were recruited from local running clubs. After screening, eligible participants were asked to cease all training and vigorous physical activity for 10 consecutive days. Before and immediately after the exercise cessation period, rCBF was measured with perfusion-weighted MRI. A voxel-wise analysis was used in gray matter, and the hippocampus was selected a priori as a structurally defined region of interest (ROI), to detect rCBF changes over time. Resting CBF significantly decreased in eight gray matter brain regions. These regions included: (L) inferior temporal gyrus, fusiform gyrus, inferior parietal lobule, (R) cerebellar tonsil, lingual gyrus, precuneus, and bilateral cerebellum (FWE p < 0.05). Additionally, rCBF within the left and right hippocampus significantly decreased after 10 days of no exercise training. These findings suggest that the cerebrovascular system, including the regulation of resting hippocampal blood flow, is responsive to short-term decreases in exercise training among master athletes. Cessation of exercise training among physically fit individuals may provide a novel method to assess the effects of acute exercise and exercise training on brain function in older adults. PMID:27547184

  4. Ultra-high spatial resolution basal and evoked cerebral blood flow MRI of the rat brain.

    PubMed

    Shen, Qiang; Huang, Shiliang; Duong, Timothy Q

    2015-03-01

    Cerebral blood flow (CBF) is tightly coupled to metabolism and neural activity under normal physiological conditions, and is often perturbed in disease states. The goals of this study were to implement a high-resolution (up to 50×38μm(2)) CBF MRI protocol of the rat brain, create a digital CBF atlas, report CBF values for 30+ brain structures based on the atlas, and explore applications of high-resolution CBF fMRI of forepaw stimulation. Excellent blood-flow contrasts were observed among different cortical and subcortical structures. CBF MRI showed column-like alternating bright and dark bands in the neocortices, reflecting the layout of descending arterioles and ascending venules, respectively. CBF MRI also showed lamina-like alternating bright and dark layers across the cortical thicknesses, consistent with the underlying vascular density. CBF profiles across the cortical thickness showed two peaks in layers IV and VI and a shallow trough in layer V. Whole-brain CBF was about 0.89ml/g/min, with the highest CBF values found amongst the neocortical structures (1ml/g/min, range: 0.89-1.16ml/g/min) and the lowest CBF values in the corpus callosum (0.32ml/g/min), yielding a gray:white matter CBF ratio of 3.1. CBF fMRI responses peaked across layers IV-V, whereas the BOLD fMRI responses showed a peak in the superficial layers II-III. High-resolution basal CBF MRI, evoked CBF fMRI, and CBF brain atlas can be used to study neurological disorders (such as ischemic stroke). PMID:25557404

  5. Distribution of cerebral blood flow during halothane versus isoflurane anesthesia in rats

    SciTech Connect

    Hansen, T.D.; Warner, D.S.; Todd, M.M.; Vust, L.J.; Trawick, D.C.

    1988-09-01

    The effects of halothane versus isoflurane on distribution of cerebral blood flow (CBF) were compared using 14C-iodoantipyrine autoradiography. Sprague-Dawley rats were exposed to 1 MAC of either halothane (n = 8) or isoflurane (n = 7) in 33% O2/balance nitrogen for 55 min prior to determination of CBF. Normoxia, normothermia, and normocapnia were maintained throughout the experiment and arterial pressures (MAP) were held within the range of 90-100 mmHg by infusion of blood. Coronal autoradiographic brain images were then digitized and optical density values converted to CBF with the use of 14C autoradiographic standards and arterial radioactivity data. Hemispheric, neocortical, subcortical, and selected local anatomical regions were defined on a cathode ray screen display by cursor outline. Mean CBF for each region was determined at each of eight standardized coronal brain sections, and area weighted average values for the whole brain were also calculated. Hemispheric CBF was identical in the two anesthetic groups: halothane = 150 +/- 16 ml.100 gm-1.min-1; isoflurane = 147 +/- 19 ml.100 gm-1.min-1. However, neocortical CBF was greater in halothane anesthetized animals (halothane = 185 +/- 16 ml.100 gm-1.min-1; isoflurane = 154 +/- 19 ml.100 gm-1.min-1, P = .004). The authors conclude that halothane and isoflurane exert regionally selective effects on CBF with halothane appearing to have a more pronounced effect on the neocortex. Previously reported discrepancies concerning the relative effects of these two agents on CBF may be due to inherent differences in the tissue regions measured by the different techniques.

  6. Characterizing the white matter hyperintensity penumbra with cerebral blood flow measures

    PubMed Central

    Promjunyakul, N.; Lahna, D.; Kaye, J.A.; Dodge, H.H.; Erten-Lyons, D.; Rooney, W.D.; Silbert, L.C.

    2015-01-01

    Objective White matter hyperintensities (WMHs) are common with age, grow over time, and are associated with cognitive and motor impairments. Mechanisms underlying WMH growth are unclear. We aimed to determine the presence and extent of decreased normal appearing white matter (NAWM) cerebral blood flow (CBF) surrounding WMHs to identify ‘WM at risk’, or the WMH CBF penumbra. We aimed to further validate cross-sectional finding by determining whether the baseline WMH penumbra CBF predicts the development of new WMHs at follow-up. Methods Sixty-one cognitively intact elderly subjects received 3 T MPRAGE, FLAIR, and pulsed arterial spin labeling (PASL). Twenty-four subjects returned for follow-up MRI. The inter-scan interval was 18 months. A NAWM layer mask, comprised of fifteen layers, 1 mm thick each surrounding WMHs, was generated for periventricular (PVWMH) and deep (DWMH) WMHs. Mean CBF for each layer was computed. New WMH and persistent NAWM voxels for each penumbra layer were defined from follow-up MRI. Results CBF in the area surrounding WMHs was significantly lower than the total brain NAWM, extending approximately 12 mm from both the established PVWMH and DWMH. Voxels with new WMH at follow-up had significantly lower baseline CBF than voxels that maintained NAWM, suggesting that baseline CBF can predict the development of new WMHs over time. Conclusions A CBF penumbra exists surrounding WMHs, which is associated with future WMH expansion. ASL MRI can be used to monitor interventions to increase white matter blood flow for the prevention of further WM damage and its cognitive and motor consequences. PMID:26106546

  7. Umbilical cord blood biomarkers of neurologic injury and the risk of cerebral palsy or infant death.

    PubMed

    Costantine, Maged M; Weiner, Steven J; Rouse, Dwight J; Hirtz, Deborah G; Varner, Michael W; Spong, Catherine Y; Mercer, Brian M; Iams, Jay D; Wapner, Ronald J; Sorokin, Yoram; Thorp, John M; Ramin, Susan M; O'Sullivan, Mary J; Peaceman, Alan M; Simhan, Hyagriv N

    2011-12-01

    To evaluate the association between cerebral palsy (CP) or infant death and putative cord blood biomarkers of neurologic injury, we performed a nested case-control secondary analysis of a multicenter randomized trial of magnesium sulfate (MgSO(4)) versus placebo to prevent CP or death among offspring of women with anticipated delivery from 24 to 31 weeks' gestation. Cases were infants who died by 1 year (n=25) or developed CP (n=16), and were matched 1:2 to a control group (n=82) that survived without developing CP. Umbilical cord sera concentrations of S100B, neuron-specific enolase (NSE) and the total soluble form of the receptor for advanced glycation end-products (sRAGE) were measured by ELISA in duplicates. Maternal characteristics were similar between the 2 groups. Cases were born at a lower gestational age (GA) and had lower birth weight compared with controls. There were no differences in concentrations of the three biomarkers and the composite outcome of CP or infant death. However, S100B was higher (median 847.3 vs. 495.7 pg/ml; P=0.03) in infants who had CP and total sRAGE was lower (median 1259.3 vs. 1813.1 pg/ml; P=0.02) in those who died compared with the control group. When corrected for delivery GA and treatment group, both differences lost statistical significance. In conclusion, cord blood S100B level may be associated with CP, but this association was not significant after controlling for GA and MgSO(4) treatment. PMID:21736934

  8. Umbilical Cord Blood Biomarkers of Neurologic Injury and the Risk of Cerebral Palsy or Infant Death

    PubMed Central

    Costantine, Maged M.; Weiner, Steven J.; Rouse, Dwight J.; Hirtz, Deborah G.; Varner, Michael W.; Spong, Catherine Y.; Mercer, Brian M.; Iams, Jay D.; Wapner, Ronald J.; Sorokin, Yoram; Thorp, John M.; Ramin, Susan M.; O'Sullivan, Mary J.; Peaceman, Alan M.; Simhan, Hyagriv N.

    2011-01-01

    To evaluate the association between cerebral palsy (CP) or infant death and putative cord blood biomarkers of neurologic injury, we performed a nested case-control secondary analysis of a multicenter randomized trial of magnesium sulfate (MgSO4) versus placebo to prevent CP or death among offspring of women with anticipated delivery from 24 – 31 weeks' gestation. Cases were infants who died by 1 year (n=25) or developed CP (n=16), and were matched 1:2 to a control group (n=82) that survived without developing CP. Umbilical cord sera concentrations of S100B, neuron-specific enolase (NSE) and the total soluble form of the receptor for advanced glycation end-products (sRAGE) were measured by ELISA in duplicates. Maternal characteristics were similar between the 2 groups. Cases were born at a lower gestational age (GA) and had lower birth weight compared with controls. There were no differences in concentrations of the three biomarkers and the composite outcome of CP or infant death. However, S100B was higher (median 847.3 vs. 495.7 pg/ml; p=0.03) in infants who had CP and total sRAGE was lower (median 1259.3 vs. 1813.1 pg/ml; p=0.02) in those who died compared with the control group. When corrected for delivery GA and treatment group, both differences lost statistical significance. In conclusion, cord blood S100B level may be associated with CP, but this association was not significant after controlling for GA and MgSO4 treatment. PMID:21736934

  9. Electrocardiographic abnormalities and home blood pressure in treated elderly hypertensive patients: Japan home versus office blood pressure measurement evaluation in the elderly (J-HOME-Elderly) study.

    PubMed

    Shibamiya, Taku; Obara, Taku; Ohkubo, Takayoshi; Shinki, Takahiro; Ishikura, Kazuki; Yoshida, Makoto; Satoh, Michihiro; Hashimoto, Takanao; Hara, Azusa; Metoki, Hirohito; Inoue, Ryusuke; Asayama, Kei; Kikuya, Masahiro; Imai, Yutaka

    2010-07-01

    This study compares relationships between each of morning home blood pressure (BP), evening home BP and office BP with electrocardiographic (ECG) abnormalities among treated hypertensive Japanese patients. We defined ECG left ventricular hypertrophy (LVH) as Sokolow-Lyon voltage and/or Cornell voltage duration product. Abnormal T waves and ST segment depression were categorized based on the Minnesota code. Office BP was calculated as the mean of four readings taken during two visits. Morning and evening home BP were calculated as the mean of five readings measured once each morning and evening for 5 days, respectively. Multivariate analysis showed that ECG-LVH in 747 hypertensives (mean age: 72 years; women: 63%) was more closely associated with morning home BP than with either office or evening home BP. Even the first reading of morning home BP on day 1 was significantly associated with ECG-LVH independently of office BP. The association between home BP and ECG-LVH increased with the cumulative number of home BP measurements. The results for abnormal T waves were similar. Home and office BP did not significantly differ between patients with and without ST segment depression. Morning home BP was more closely associated with ECG-LVH and abnormal T waves than either office or evening home BP among treated hypertensive Japanese patients. PMID:20431591

  10. Protective effects of taurine in traumatic brain injury via mitochondria and cerebral blood flow.

    PubMed

    Wang, Qin; Fan, Weijia; Cai, Ying; Wu, Qiaoli; Mo, Lidong; Huang, Zhenwu; Huang, Huiling

    2016-09-01

    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. PMID:27156064

  11. Blood-Brain Barrier Dysfunction and Cerebral Small Vessel Disease (Arteriolosclerosis) in Brains of Older People

    PubMed Central

    Khoong, Cheryl H.L.; Poon, Wayne; Esiri, Margaret M.; Markus, Hugh S.; Hainsworth, Atticus H.

    2014-01-01

    The blood-brain barrier (BBB) protects brain tissue from potentially harmful plasma components. Small vessel disease ([SVD], arteriolosclerosis) is common in the brains of older people and is associated with lacunar infarcts, leukoaraiosis and vascular dementia. To determine whether plasma extravasation is associated with SVD, we immunolabeled the plasma proteins fibrinogen and IgG, which are assumed to reflect BBB dysfunction, in deep grey matter (anterior caudate-putamen, [DGM]) and deep subcortical white matter (DWM) in the brains of a well-characterized patient cohort with minimal Alzheimer disease pathology (Braak stage 0-II) (n = 84; age ≥65 years). Morphometric measures of fibrinogen labeling were compared between people with neuropathologically defined SVD and aged control subjects. Parenchymal cellular labeling with fibrinogen and IgG was detectable in DGM and DWM in many subjects (>70%). Quantitative measures of fibrinogen were not associated with SVD in DGM or DWM; SVD severity was correlated between DGM and DWM (p < 0.0001). Fibrinogen in DGM showed a modest association with a history of hypertension; DWM fibrinogen was associated with dementia and cerebral amyloid angiopathy (all p < 0.05). In DWM, SVD was associated with leukoaraiosis identified in life (p < 0.05), but fibrinogen was not. Our data suggest that in aged brains plasma extravasation and hence local BBB dysfunction is common but do not support an association with SVD. PMID:25289893

  12. Iron transport across the blood-brain barrier; Development, neurovascular regulation and cerebral amyloid angiopathy

    PubMed Central

    McCarthy, Ryan C; Kosman, Daniel J

    2014-01-01

    There are two barriers for iron entry into the brain: 1) the brain-cerebrospinal fluid (CSF) barrier and 2) the blood-brain barrier (BBB). Here, we review the literature on developmental iron accumulation by the brain, focusing on the transport of iron through the brain microvascular endothelial cells (BMVEC) of the BBB. We review the iron trafficking proteins which may be involved in the iron flux across BMVEC and discuss the plausible mechanisms of BMVEC iron uptake and efflux. We suggest a model for how BMVEC iron uptake and efflux are regulated and a mechanism by which the majority of iron is trafficked across the developing BBB under the direct guidance of neighboring astrocytes. Thus, we place brain iron uptake in the context of the neurovascular unit of the adult brain. Last, we propose that BMVEC iron is involved in the aggregation of amyloid-β peptides leading to the progression of cerebral amyloid angiopathy which often occurs prior to dementia and the onset of Alzheimer's disease. PMID:25355056

  13. Venous cerebral blood volume increase during voluntary locomotion reflects cardiovascular changes.

    PubMed

    Huo, Bing-Xing; Greene, Stephanie E; Drew, Patrick J

    2015-09-01

    Understanding how changes in the cardiovascular system contribute to cerebral blood flow (CBF) and volume (CBV) increases is critical for interpreting hemodynamic signals. Here we investigated how systemic cardiovascular changes affect the cortical hemodynamic response during voluntary locomotion. In the mouse, voluntary locomotion drives an increase in cortical CBF and arterial CBV that is localized to the forelimb/hindlimb representation in the somatosensory cortex, as well as a diffuse venous CBV increase. To determine if the heart rate increases that accompany locomotion contribute to locomotion-induced CBV and CBF increases, we occluded heart rate increases with the muscarinic cholinergic receptor antagonist glycopyrrolate, and reduced heart rate with the β1-adrenergic receptor antagonist atenolol. We quantified the effects of these cardiovascular manipulations on CBV and CBF dynamics by comparing the hemodynamic response functions (HRF) to locomotion across these conditions. Neither the CBF HRF nor the arterial component of the CBV HRF was significantly affected by pharmacological disruption of the heart rate. In contrast, the amplitude and spatial extent of the venous component of the CBV HRF were decreased by atenolol. These results suggest that the increase in venous CBV during locomotion was partially driven by peripheral cardiovascular changes, whereas CBF and arterial CBV increases associated with locomotion reflect central processes. PMID:26057593

  14. Quantifying local cerebral blood flow by N-isopropyl-p-(123I)iodoamphetamine (IMP) tomography

    SciTech Connect

    Kuhl, D.E.; Barrio, J.R.; Huang, S.C.; Selin, C.; Ackermann, R.F.; Lear, J.L.; Wu, J.L.; Lin, T.H.; Phelps, M.E.

    1982-03-01

    A model was validated wherein local cerebral blood flow (LCBF) in humans was quantified by single-photon emission computed tomography (SPECT) with intravenously injected N-isopropyl-p-(123I)iodoamphetamine (IMP) combined with a modification of the classic method of arterial input sampling. After intravenous injection of IMP in rat, autoradiograms of the brain showed activity distributions in the pattern of LCBF. IMP was nearly completely removed on first pass through monkey brain after intracarotid injection (CBF.33 ml/100 g/min) and washed out with a half-time of approximately 1 hr. When the modified method of arterial input and tissue-sample counting applied to dog brain, there was good correspondence between LCBF based on IMP and on that by microsphere injection over a wide flow range. In applying the method to human subjects using SPECT, whole-brain CBF measured 47.2 +/- 5.4 ml/100 g/min (mean +/- s.d., N.5), stable gray-white distinction persisted for over 1 hr, and the half-time for brain washout was approximately 1 hr. Perfusion deficits in patients were clearly demonstrated and quantified, comparing well with results now available from positron ECT.

  15. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    PubMed Central

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-01-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. PMID:16306271

  16. New insights into coupling and uncoupling of cerebral blood flow and metabolism in the brain

    PubMed Central

    Venkat, Poornima; Chopp, Michael; Chen, Jieli

    2016-01-01

    The brain has high metabolic and energy needs and requires continuous cerebral blood flow (CBF), which is facilitated by a tight coupling between neuronal activity, CBF, and metabolism. Upon neuronal activation, there is an increase in energy demand, which is then met by a hemodynamic response that increases CBF. Such regional CBF increase in response to neuronal activation is observed using neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography. The mechanisms and mediators (eg, nitric oxide, astrocytes, and ion channels) that regulate CBF-metabolism coupling have been extensively studied. The neurovascular unit is a conceptual model encompassing the anatomical and metabolic interactions between the neurons, vascular components, and glial cells in the brain. It is compromised under disease states such as stroke, diabetes, hypertension, dementias, and with aging, all of which trigger a cascade of inflammatory responses that exacerbate brain damage. Hence, tight regulation and maintenance of neurovascular coupling is central for brain homeostasis. This review article also discusses the waste clearance pathways in the brain such as the glymphatic system. The glymphatic system is a functional waste clearance pathway that removes metabolic wastes and neurotoxins from the brain along paravascular channels. Disruption of the glymphatic system burdens the brain with accumulating waste and has been reported in aging as well as several neurological diseases. PMID:27374823

  17. Impact of Gas Delivery Systems on Imaging Studies of Human Cerebral Blood Flow

    PubMed Central

    Cain, John R.; Parkes, Laura M.; Eadsforth, Peter; Beards, Susan C.; Jackson, Alan

    2013-01-01

    Purpose. To compare a semiopen breathing circuit with a non-rebreathing (Hudson mask) for MRI experiments involving gas delivery. Methods and Materials. Cerebral blood flow (CBF) was measured by quantitative phase contrast angiography of the internal carotid and basilar arteries in 18 volunteers (20–31 years). In 8 subjects, gases were delivered via a standard non-rebreathing (Hudson mask). In 10 subjects, gases were delivered using a modified “Mapleson A” semiopen anesthetic gas circuit and mouthpiece. All subjects were given 100% O2, medical air, and carbogen gas (95% O2 and 5% CO2) delivered at 15 L/min in a random order. Results. The Hudson mask group showed significant increases in CBF in response to increased FiCO2 compared to air (+9.8%). A small nonsignificant reduction in CBF (−2.4%) was seen in response to increased inspired concentrations of oxygen (FiO2). The Mapleson A group showed significantly larger changes in CBF in response to both increased inspired concentrations of carbon dioxide (FiCO2) (+32.2%, P < 0.05) and FiO2 (−14.6%, P < 0.01). Conclusions. The use of an anaesthetic gas delivery circuit avoids entrainment of room air and rebreathing effects that may otherwise adversely affect the experimental results. PMID:24392225

  18. Impact of gas delivery systems on imaging studies of human cerebral blood flow.

    PubMed

    Cain, John R; Parkes, Laura M; Eadsforth, Peter; Beards, Susan C; Jackson, Alan

    2013-01-01

    Purpose. To compare a semiopen breathing circuit with a non-rebreathing (Hudson mask) for MRI experiments involving gas delivery. Methods and Materials. Cerebral blood flow (CBF) was measured by quantitative phase contrast angiography of the internal carotid and basilar arteries in 18 volunteers (20-31 years). In 8 subjects, gases were delivered via a standard non-rebreathing (Hudson mask). In 10 subjects, gases were delivered using a modified "Mapleson A" semiopen anesthetic gas circuit and mouthpiece. All subjects were given 100% O2, medical air, and carbogen gas (95% O2 and 5% CO2) delivered at 15 L/min in a random order. Results. The Hudson mask group showed significant increases in CBF in response to increased FiCO2 compared to air (+9.8%). A small nonsignificant reduction in CBF (-2.4%) was seen in response to increased inspired concentrations of oxygen (FiO2). The Mapleson A group showed significantly larger changes in CBF in response to both increased inspired concentrations of carbon dioxide (FiCO2) (+32.2%, P < 0.05) and FiO2 (-14.6%, P < 0.01). Conclusions. The use of an anaesthetic gas delivery circuit avoids entrainment of room air and rebreathing effects that may otherwise adversely affect the experimental results. PMID:24392225

  19. Unsymmetrical alkyl aryl thiourae compounds for use as cerebral blood flow tracers. [Rats

    SciTech Connect

    Goldman, S.S.; Haas, W.K.; Ransohoff, J.

    1980-06-01

    The synthesis and characterization of an homologous series of inert nonvolatile /sup 14/C-labeled unsymmetrical alkyl aryl thiourea compounds is described for their use as regional blood flow (rCBF) tracers employing autoradiographic procedures. In alert normocapnic rats the single-pass extraction values into brain for these thioureas were found ranging from 0.497 for 1-methyl-3-phenylthiourea to 0.730 for 1-butyl-3-phenylthiourea. The commonly used rCBF tracers (14C) antipyrine and (14C) iodoantipyrine had single-pass extraction values of 0.451 and 0.553, respectively. Since 1-butyl-3-phenylthiourea diffused most readily into rat brain it was chosen as a potentially valuable rCBF tracer. Employing 1-butyl-3-phenylthiourea to measure rCBF nd its empirically derived brain extraction values the following flow rates in normocapnic rats were found: 3.2 ml . g-1 . min-1 for cochlear nucleus: 3.0 for inferior colliculus; 2.5 for medical geniculate; 1.9 for pontine gray and hypothalamus; 1.7 for caudate and cerebral cortex; and 1.2 for cerebellar gray and 0.41 to 0.50 for white matter structures. It was concluded from these studies that 1-butyl-3-phenylthiourea is more advantageous than iodoantipyrine for measuring rCBF, especially in those areas that possess very rapid rates of flow.

  20. beta. -Receptor-mediated increase in cerebral blood flow during hypoglycemia

    SciTech Connect

    Hollinger, B.R.; Bryan, R.M. )

    1987-10-01

    The authors tested the hypothesis that {beta}-adrenergic receptor stimulation is involved with the increase in regional cerebral blood flow (rCBF) during hypoglycemia. Rats were surgically prepared with the use of halothane-nitrous oxide anesthesia. A plaster restraining cast was placed around the hindquarters, and anesthesia was discontinued. Hypoglycemia was produced by an intravenous injection of insulin; normoglycemic control rates were given saline. Propranolol was administered to some control and some hypoglycemic rats to block the {beta}-adrenergic receptors. Regional CBF was measured using 4-(N-methyl-{sup 14}C)iodoantipyrine. Regional CBF increased during hypoglycemia in rats that were not treated with propranolol. The increase varied from {approximately}60 to 200% depending on the brain region. During hypoglycemia, propranolol abolished the increase in rCBF in the hypothalamus, cerebellum, and pyramidal tract. In other regions the increase in rCBF was only 33-65% of the increase in hypoglycemic rats that were not treated with propranolol. They conclude that {beta}-receptor stimulation plays a major role in the increase in rCBF during hypoglycemia.

  1. Prospective analysis of long term control of mild hypertension on cerebral blood flow

    SciTech Connect

    Meyer, J.S.; Rogers, R.L.; Mortel, K.F.

    1985-11-01

    A group of 12 otherwise normal elderly volunteers (mean age = 69.8 years), were detected to have mild hypertension. Cerebral blood flow (CBF) values were measured using 133Xe inhalation method prior to initiating medical treatment and repeated at 6, 12, 24 and 36 months after BP was adequately controlled and restored to normal (below 150/90). Results indicate that CBF values increased markedly during follow-up intervals at 6, 12 and 24 months but not at 36 months. Hypertension is known to be a risk factor for stroke and 4 of the 12 subjects subsequently developed symptoms of cerebrovascular disease (stroke, multi-infarct dementia or transient ischemic attacks) despite control of hypertension. Analyses separating asymptomatic and symptomatic groups indicated that the eight asymptomatic patients continued to maintain increased CBF levels throughout the entire three year interval, whereas the 4 symptomatic patients developed declines in CBF which began, and progressively decreased below the initial pretreatment values, during the second and third years.

  2. Influence of regional cerebral blood volume on voxel-based morphometry.

    PubMed

    Zheng, Lei; Cleppien, Dirk; Gass, Natalia; Falfan-Melgoza, Claudia; Vollmayr, Barbara; Hesser, Jürgen; Weber-Fahr, Wolfgang; Sartorius, Alexander

    2016-06-01

    The investigation of structural brain alterations is one focus in research of brain diseases like depression. Voxel-based morphometry (VBM) based on high-resolution 3D MRI images is a widely used non-invasive tool for such investigations. However, the result of VBM might be sensitive to local physiological parameters such as regional cerebral blood volume (rCBV) changes. In order to investigate whether rCBV changes may contribute to variation in VBM, we performed analyses in a study with the congenital learned helplessness (cLH) model for long-term findings. The 3D structural and rCBV data were acquired with T2 -weighted rapid acquisition with relaxation enhancement (RARE) pulse sequences. The group effects were determined by standard statistical parametric mapping (SPM) and biological parametric mapping (BPM) and examined further using atlas-based regions. In our genetic animal model of depression, we found co-occurrence of differences in gray matter volume and rCBV, while there was no evidence of significant interaction between both. However, the multimodal analysis showed similar gray matter differences compared with the standard VBM approach. Our data corroborate the idea that two group VBM differences might not be influenced by rCBV differences in genetically different strains. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27074152

  3. Cerebral blood flow velocity and cranial fluid volume decrease during +Gz acceleration

    NASA Technical Reports Server (NTRS)

    Kawai, Y.; Puma, S. C.; Hargens, A. R.; Murthy, G.; Warkander, D.; Lundgren, C. E.

    1997-01-01

    Cerebral blood flow (CBF) velocity and cranial fluid volume, which is defined as the total volume of intra- and extracranial fluid, were measured using transcranial Doppler ultrasonography and rheoencephalography, respectively, in humans during graded increase of +Gz acceleration (onset rate: 0.1 G/s) without straining maneuvers. Gz acceleration was terminated when subjects' vision decreased to an angle of less than or equal to 60 degrees, which was defined as the physiological end point. In five subjects, mean CBF velocity decreased 48% from a baseline value of 59.4 +/- 11.2 cm/s to 31.0 +/- 5.6 cm/s (p<0.01) with initial loss of peripheral vision at 5.7 +/- 0.9 Gz. On the other hand, systolic CBF velocity did not change significantly during increasing +Gz acceleration. Cranial impedance, which is proportional to loss of cranial fluid volume, increased by 2.0 +/- 0.8% above the baseline value at the physiological end point (p<0.05). Both the decrease of CBF velocity and the increase of cranial impedance correlated significantly with Gz. These results suggest that +Gz acceleration without straining maneuvers decreases CBF velocity to half normal and probably causes a caudal fluid shift from both intra- and extracranial tissues.

  4. Rapid decline and recovery of cerebral blood flow on return to upright posture

    NASA Astrophysics Data System (ADS)

    Zuj, Kathryn; Harvey, D.; Wheaton, L.; Hughson, R. L.

    2006-05-01

    We examined cardiovascular and cerebrovascular regulation during standing. Nine women and nine men completed 10 min supine rest followed by 70 s standing. We also studied the effectiveness of the cardiopulmonary baroreflex (CPBR) during three levels of LBNP (-10,-20,-30mmHg). Mean flow velocity (MFVMCA) from the right middle cerebral artery (MCA, transcranial Doppler ultrasound), mean arterial pressure (MAP, Finapres), blood pressure at the level of the MCA (BPMCA), and heart rate (HR) were monitored. An index of cerebrovascular resistance (CVRi) was calculated by CVRi=BPMCA/MFVMCA. Baseline values for MAP, MFVMCA, BPMCA, CVRi, and HR were not statistically different between men and women (P>0.1). The 'stand' tests resulted in initial decreases in MAP (19.6-40.5%), MFVMCA (13.0-51.5%), BPMCA (54.6-81.0%), CVRi (49.3-73.1%) and an increase in HR (30.1-106.3%). A greater decrease in MFVMCA, as a percentage of baseline, was seen for men (P=0.007). Men also showed a greater percentage change in MAP (P<0.004) and BPMCA(P<0.04). In the subjects studied for CPBR gain, the preliminary data revealed a negative correlation between reduction in MAP and CPBR gain (r=-0.648). Thus, it is possible the gender difference of smaller declines in MAP for women might have been related to relatively greater CPBR gains.

  5. New insights into coupling and uncoupling of cerebral blood flow and metabolism in the brain.

    PubMed

    Venkat, Poornima; Chopp, Michael; Chen, Jieli

    2016-06-30

    The brain has high metabolic and energy needs and requires continuous cerebral blood flow (CBF), which is facilitated by a tight coupling between neuronal activity, CBF, and metabolism. Upon neuronal activation, there is an increase in energy demand, which is then met by a hemodynamic response that increases CBF. Such regional CBF increase in response to neuronal activation is observed using neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography. The mechanisms and mediators (eg, nitric oxide, astrocytes, and ion channels) that regulate CBF-metabolism coupling have been extensively studied. The neurovascular unit is a conceptual model encompassing the anatomical and metabolic interactions between the neurons, vascular components, and glial cells in the brain. It is compromised under disease states such as stroke, diabetes, hypertension, dementias, and with aging, all of which trigger a cascade of inflammatory responses that exacerbate brain damage. Hence, tight regulation and maintenance of neurovascular coupling is central for brain homeostasis. This review article also discusses the waste clearance pathways in the brain such as the glymphatic system. The glymphatic system is a functional waste clearance pathway that removes metabolic wastes and neurotoxins from the brain along paravascular channels. Disruption of the glymphatic system burdens the brain with accumulating waste and has been reported in aging as well as several neurological diseases. PMID:27374823

  6. Cerebral blood flow determinations using fluorescent microspheres: variations on the sedimentation method validated.

    PubMed

    Powers, K M; Schimmel, C; Glenny, R W; Bernards, C M

    1999-03-01

    We validate a modification of the sedimentation method for measuring fluorescent microspheres (FM) that improves the determination of regional cerebral blood flow (rCBF). Our FM method for rCBF determination is compared to the radioactive microspheres (RM) method for rCBF measurement by simultaneous injection of one radioactive and two fluorescent labeled doses, at two separate time points, into the left ventricle of a pig. The pig was killed, the brain and spinal cord removed, and divided into 92 pieces averaging 0.83 g. Our modifications to FM analysis by sedimentation includes: 2 instead of 1 week of autolysis, pellet washing with 1% Triton X-100 instead of 0.25% Tween 80, phosphate buffer addition during rinse, fluorescent dye extraction using 2-ethoxyethylacetate instead of 2-(2-ethoxyethoxy)ethyl acetate and polypropylene instead of glass tubes. Comparing rCBF using Sc46 RM, to yellow-green and orange FM, yielded mean differences of 0.026 and 0.021 ml/min per piece, respectively. Sn(113) RM compared to blue-green and scarlet FM gave mean differences of -0.010 and 0.137 ml/min per piece, respectively. All RM-FM differences, except those for scarlet FM, are within acceptable limits. This assay provides a reliable method for determining rCBF. PMID:11230812

  7. Computational model of cerebral blood flow redistribution during cortical spreading depression

    NASA Astrophysics Data System (ADS)

    Verisokin, Andrey Y.; Verveyko, Darya V.; Postnov, Dmitry E.

    2016-04-01

    In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem. In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.

  8. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    NASA Astrophysics Data System (ADS)

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-12-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. anterior cingulate cortex | arterial spin labeling | right prefrontal cortex

  9. Pharmacotherapy response and regional cerebral blood flow characteristics in patients with obsessive-compulsive disorder

    PubMed Central

    2013-01-01

    Objective To analyze the correlation between the pharmacotherapy response and the characteristics of the pre-treatment regional cerebral blood flow (rCBF) in patients with obsessive-compulsive disorder (OCD). Methods Single-photon emission-computed tomography (SPECT) was used to determine the pre-treatment rCBF in 30 OCD patients and 30 normal controls. Based on their clinical remission response, the subjects were divided into two groups: selective serotonin reuptake inhibitors (SSRIs) and SSRIs plus quetiapine. The subjects with clinical remission response were identified after treatment for a period of 24 weeks, and the rCBF imaging data were processed using statistical parametric mapping (SPM) software with two-sample Z-tests. Results Nineteen OCD patients who achieved clinical remission were included in the study. Increased rCBF in forebrain regions, including the frontal lobe, cingulate gyrus, hypothalamus, and basal ganglia, was found in 11 responders to SSRIs compared to normal control patients. The eight SSRI plus quetiapine responders exhibited a decrease in rCBF within posterior brain regions, including the parietal lobe, cerebellar vermis, and occipital lobe, and an increase in rCBF in the frontal lobe, thalamus, basal ganglia, and cerebellum tonsil compared to normal control patients. Conclusions The characteristics of increased rCBF in forebrain regions and decreased rCBF in posterior brain regions before treatment of OCD patients was a potentially predictor of treatment response to guide treatment options. PMID:23898909

  10. Measurement of cerebral blood volume using angiographic C-arm systems

    NASA Astrophysics Data System (ADS)

    Zellerhoff, Michael; Deuerling-Zheng, Yu; Strother, Charles M.; Ahmed, Azam; Pulfer, Kari; Redel, Thomas; Royalty, Kevin; Grinde, Julie; Consigny, Dan

    2009-02-01

    While perfusion imaging is a well established diagnostic imaging technique, until now, it could not be performed using angiographic equipment. The ability to assess information about tissue perfusion in the angiographic suite should help to optimize management of patients with neurovascular diseases. We present a technique to measure cerebral blood volume (CBV) for the entire brain using an angiographic C-arm system. Combining a rotational acquisition protocol similar to that used for standard three-dimensional rotational angiography (3D DSA) in conjunction with a modified injection protocol providing a steady state of tissue contrast during the acquisition the data necessary to calculate CBV is acquired. The three-dimensional (3D) CBV maps are generated using a special reconstruction scheme which includes the automated detection of an arterial input function and several correction steps. For evaluation we compared this technique with standard perfusion CT (PCT) measurements in five healthy canines. Qualitative comparison of the CBV maps as well as quantitative comparison using 12 ROIs for each map showed a good correlation between the new technique and traditional PCT. In addition we evaluated the technique in a stroke model in canines. The presented technique provides the first step toward providing information about tissue perfusion available during the treatment of neurovascular diseases in the angiographic suite.

  11. Interactive effects of vascular risk burden and advanced age on cerebral blood flow

    PubMed Central

    Bangen, Katherine J.; Nation, Daniel A.; Clark, Lindsay R.; Harmell, Alexandrea L.; Wierenga, Christina E.; Dev, Sheena I.; Delano-Wood, Lisa; Zlatar, Zvinka Z.; Salmon, David P.; Liu, Thomas T.; Bondi, Mark W.

    2014-01-01

    Vascular risk factors and cerebral blood flow (CBF) reduction have been linked to increased risk of cognitive impairment and Alzheimer's disease (AD); however the possible moderating effects of age and vascular risk burden on CBF in late life remain understudied. We examined the relationships among elevated vascular risk burden, age, CBF, and cognition. Seventy-one non-demented older adults completed an arterial spin labeling MR scan, neuropsychological assessment, and medical history interview. Relationships among vascular risk burden, age, and CBF were examined in a priori regions of interest (ROIs) previously implicated in aging and AD. Interaction effects indicated that, among older adults with elevated vascular risk burden (i.e., multiple vascular risk factors), advancing age was significantly associated with reduced cortical CBF whereas there was no such relationship for those with low vascular risk burden (i.e., no or one vascular risk factor). This pattern was observed in cortical ROIs including medial temporal (hippocampus, parahippocampal gyrus, uncus), inferior parietal (supramarginal gyrus, inferior parietal lobule, angular gyrus), and frontal (anterior cingulate, middle frontal gyrus, medial frontal gyrus) cortices. Furthermore, among those with elevated vascular risk, reduced CBF was associated with poorer cognitive performance. Such findings suggest that older adults with elevated vascular risk burden may be particularly vulnerable to cognitive change as a function of CBF reductions. Findings support the use of CBF as a potential biomarker in preclinical AD and suggest that vascular risk burden and regionally-specific CBF changes may contribute to differential age-related cognitive declines. PMID:25071567

  12. Bilateral behavioral and regional cerebral blood flow changes during painful peripheral mononeuropathy in the rat

    PubMed Central

    Paulson, Pamela E.; Morrow, Thomas J.; Casey,