WorldWideScience

Sample records for blood flow cbf

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

    Science.gov (United States)

    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.

  2. Regional cerebral blood flow (rCBF) in man during perception of radiant warmth and heat pain.

    Science.gov (United States)

    Ryding, E; Eriksson, M B; Rosén, I; Ingvar, D H

    1985-08-01

    The present study concerns the effects of experimental pain (radiant warmth and heat pain) on regional cerebral blood flow (rCBF) in pretrained subjects. The radiant warmth caused a general rCBF increase. However, if anxiety was avoided, heat pain caused the general rCBF level to return towards the level at rest. Thus, pain sensation per se may not cause a larger rCBF (and metabolic) response than that of the localized tactile stimulation, provided that the element of psychic apprehension and anxiety is eliminated or controlled.

  3. Quantitation of regional cerebral blood flow by single photon emission computed tomography of CBF-tracer combined with whole-brain CBF; A comparison between [sup 123]I-IMP and [sup 99m]Tc-HMPAO in healthy volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Isaka, Yoshinari; Imaizumi, Masatoshi; Ashida, Keiichi; Ohe, Yosuke; Okamoto, Masaya; Abe, Tohru; Tanaka, Seiji (Osaka National Hospital (Japan))

    1994-05-01

    A simple, noninvasive method of measuring cerebral blood flow (CBF) that uses single-photon emission computed tomography (SPECT) of CBF-tracer and whole brain CBF obtained by xenon-133 ([sup 133]Xe) clearance technique was developed. In nine healthy volunteers, SPECT data were normalized to the count density of [sup 123]I-IMP or [sup 99m]Tc-HMPAO uptake in the whole-brain, and then converted to the absolute units of CBF by multiplying average [sup 133]Xe-CBF in the whole brain. The CBF values measured by [sup 99m]Tc-HMPA CBF-SPECT was significantly lower in the high flow regions of cortical gray matter (bilateral frontal lobe; p<0.05 and right occipital lobe; p<0.05), and was significantly higher in the bilateral white matter (p<0.05 or 0.01) and the cerebellum (p<0.005) compared with the flow values measured by [sup 123]I-IMP CBF-SPECT. Whereas, the IMP-CBF values were significantly lower in the bilateral striatum (p<0.02 or 0.05) compared with the HMPAO-CBF values. Good correlations were found between IMP-CBF and the HMPAO-CBF values in the cortical gray matter (r[sub s]=0.761; p<0.001, n=108), the white matter (r[sub s]=0.739; p<0.001, n=18) and the cerebellum (r[sub s]=0.731; p<0.001, n=18). In the striatum (r[sub s]=0.58; p<0.05, n=18) and the thalamus (r[sub s]=0.628; p<0.05, n=18), the correlations between IMP-CBF and HMPAO-CBF values were inferior to those of the other three regions. The results indicated that the contrast between high and low CBF regions in the HMPAO CBF-SPECT was significantly less than that in the IMP CBF-SPECT. However, this assumption is not applicable in all of the cerebral regions. (author).

  4. Haemodynamic evaluation of the cerebral circulation by periorbital Doppler examination and cerebral blood flow (CBF) measurement in carotid artery disease

    DEFF Research Database (Denmark)

    Sillesen, H; Schroeder, T; Buchardt Hansen, H J

    1988-01-01

    To assess the haemodynamic significance of an internal carotid artery (ICA) stenosis, angiography or direct ultrasound examination should be supplemented by indirect physiologic testing of the collateral circulation. Among the tests proposed, we used the periorbital flow direction, assessed by Do...

  5. Resting cerebral blood flow

    Science.gov (United States)

    Ances, B M.; Sisti, D; Vaida, F; Liang, C L.; Leontiev, O; Perthen, J E.; Buxton, R B.; Benson, D; Smith, D M.; Little, S J.; Richman, D D.; Moore, D J.; Ellis, R J.

    2009-01-01

    Objective: HIV enters the brain soon after infection causing neuronal damage and microglial/astrocyte dysfunction leading to neuropsychological impairment. We examined the impact of HIV on resting cerebral blood flow (rCBF) within the lenticular nuclei (LN) and visual cortex (VC). Methods: This cross-sectional study used arterial spin labeling MRI (ASL-MRI) to measure rCBF within 33 HIV+ and 26 HIV− subjects. Nonparametric Wilcoxon rank sum test assessed rCBF differences due to HIV serostatus. Classification and regression tree (CART) analysis determined optimal rCBF cutoffs for differentiating HIV serostatus. The effects of neuropsychological impairment and infection duration on rCBF were evaluated. Results: rCBF within the LN and VC were significantly reduced for HIV+ compared to HIV− subjects. A 2-tiered CART approach using either LN rCBF ≤50.09 mL/100 mL/min or LN rCBF >50.09 mL/100 mL/min but VC rCBF ≤37.05 mL/100 mL/min yielded an 88% (29/33) sensitivity and an 88% (23/26) specificity for differentiating by HIV serostatus. HIV+ subjects, including neuropsychologically unimpaired, had reduced rCBF within the LN (p = 0.02) and VC (p = 0.001) compared to HIV− controls. A temporal progression of brain involvement occurred with LN rCBF significantly reduced for both acute/early (<1 year of seroconversion) and chronic HIV-infected subjects, whereas rCBF in the VC was diminished for only chronic HIV-infected subjects. Conclusion: Resting cerebral blood flow (rCBF) using arterial spin labeling MRI has the potential to be a noninvasive neuroimaging biomarker for assessing HIV in the brain. rCBF reductions that occur soon after seroconversion possibly reflect neuronal or vascular injury among HIV+ individuals not yet expressing neuropsychological impairment. GLOSSARY AEH = acute/early HIV infection; ANOVA = analysis of variance; ASL-MRI = arterial spin labeling MRI; CART = classification and regression tree; CBF = cerebral blood flow; CH = chronic HIV

  6. Compromised Cerebral Blood Flow(CBF) in Congestive Heart Failure (CHB): non-invasive quantification with {sup 99m}Tc-ECD radionuclide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung; Kim, Jae Joong; Lim, Ki Chun; Lee, Hee Kyung; Moon, Dae Hyuk [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2002-07-01

    Recent reports revealed that cerebral metabolism in CHF was abnormally deranged and proposed as a potential marker of disease severity. Since deranged cerebral metabolism in CHF may result from compromised cerebral perfusion, quantification of CHF may be useful for accurate risk stratification of CHF. Therefore, we investigated whether CHF in patients with CHF is compromised and correlated with clinical parameters. Fifteen patients (M/F:11/5, 45{+-}9yr) with CHF (LVEF<40%) and 7 healthy controls (M/F:5/2, 41{+-}8yr) were prospectively studied. All patients underwent radionuclide angiography including cerebral hemispheres and aortic arch using {sup 99m}Tc-ECD. Global CBF was measured non-invasively by the application of Patlak graphical plot analysis. All patients were also evaluated using a standardized protocol that included echocardiography and clinical evaluation. Global CBF (40.3{+-}5.2 ml/min/100g) of the patients with CHF were significantly lower than those (49.7{+-}2.4 ml/min/100g) of controls (p<0.01). Global CBF were correlated with NYHA functional class (r=-0.617, p=0.43), but not correlated with other clinical parameters such as age (r=-0.463, p=0.082), duration (r=0.237, p>0.1), systolic BP (r=-0.063, p>0.5), LVEF (r=-0.13, p>0.1), LV dimension(r=0.139, p>0.5), and PV pressure gradients (r=0.072, p>0.5). Cerebral perfusion of the patients with CHF was compromised and not correlated with cardiopulmonary hemodynamic parameters.

  7. Neuromodulation of cerebral blood flow

    NARCIS (Netherlands)

    ter Laan, Mark

    2014-01-01

    Dit proefschrift behandelt de modulatie van de cerebrale doorbloeding (cerebral blood flow, CBF) door cervicale elektrische stimulatie en de aanname dat het sympathisch zenuwstelsel hierin een specifieke rol speelt. Enkele resultaten met cervicale ruggenmergsstimulatie (spinal cord stimulation, SCS)

  8. Early Rehabilitation of Acute Stroke Patients with Hemiplegia and Effects of regional Cerebral Blood Flow (rCBF) of the Patients with Cerebral Infarction by Early Rehabiiitation

    Institute of Scientific and Technical Information of China (English)

    Luo ZuMing; Xiong Hai

    2000-01-01

    Objectives: To investigate whether early rchabilitation could improve obviously clinical prognosis of acute stroke patients. The mechanism of early rehabilitation that could improve brain function was preliminarily studied. Methods: 240 patients with acute hemiplegia were randomly divided into control group (120 cases) and rehabilitation group (120 cases). The control group received general treatment and the latter received early rehabilitation (Bobath methods) besides general treatment. At pre-rehabilitation and the end of 1,2,3,4,5,6 month at post-rehabilitation, the neurological deficit was assessed with modified Edinbcrg-Scandinavian stroke scale (MESSS); the motor function of the hemiplegic limbs were assessed with modified Fugl-meyer motor scale (FM);the ADL were assessed with modified Barthel Index (MBI), and the general secondary complications of both groups were also evaluated. Moreover, rCBF of 72 cases of acute cerebral infarction with hemiplegia (34 in control group, 38 in rehabilitation group) was earned out by SPECT imaging at pre-rehabilitation and at the end of I month at post - rehabilitation.Results and Discussion: Compared with those of control group, at the end of 1,2,3,4,5,6 month at post - rehabilitation, the scores of MESSS were more obviously decreased (p<0.05 and p<0.01); the scores of MBI and FM were more significantly increased (p<0.05 and p<0.01); and morbidity of secondary complications was more significantly decreased (p<0.05 and p<0.01). Compared with those of pre-rehabilitation in rehabilitation group, both the decrease of MESS scores and the increase of FM, MBI scores were more obvious (p<0.01) at the end of 1,2,3 month of post-rehabilitation; however, compared with that of the end of 3 month at post-rehabilitation, at the end of 4,5,6 month of post-rehabilitation in rehabilitation group. Both the decrease of MESSS scores and the increase of FM scores hadn′t statistical significance (p>0.05). but scores of MBt were

  9. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only...

  10. Cerebral blood flow response to propranolol in streptozotocin diabetic rats

    DEFF Research Database (Denmark)

    Lass, Preben; Knudsen, G M

    1990-01-01

    The influence of propranolol on cerebral blood flow (CBF) was tested in streptozotocin diabetic rats and in control animals. Resting CBF values were 40% lower in the diabetic rats compared with controls. Intravenous injection of propranolol (2 mg kg-1) decreased CBF significantly in the control...

  11. Regional cerebral blood flow in aphasia

    DEFF Research Database (Denmark)

    Soh, K; Larsen, B; Skinhøj, E

    1978-01-01

    Regional cerebral blood flow (rCBF) was studied in 13 aphasic patients with left hemisphere lesions, using the intracarotid xenon 133 injection method and a 254-detector gamma camera system. The rCBF was measured during rest and during various function tests, including a simple speech test...

  12. Cerebral blood flow in acute mountain sickness

    DEFF Research Database (Denmark)

    Jensen, J B; Wright, Anne; Lassen, N A

    1990-01-01

    Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased...

  13. Regional cerebral blood flow in schizophrenia

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Cerebral blood flow and metabolism during sleep.

    Science.gov (United States)

    Madsen, P L; Vorstrup, S

    1991-01-01

    A review of the current literature regarding sleep-induced changes in cerebral blood flow (CBF) and cerebral metabolic rate (CMR) is presented. Early investigations have led to the notion that dreamless sleep was characterized by global values of CBF and CMR practically at the level of wakefulness, while rapid eye movement (REM) sleep (dream sleep) was a state characterized by a dramatically increased level of CBF and possibly also of CMR. However, recent investigations firmly contradict this notion. Investigations on CBF and CMR performed during non-REM sleep, taking the effect of different levels of sleep into consideration, show that light sleep (stage II) is characterized by global levels of CBF and CMR only slightly reduced by 3-10% below the level associated with wakefulness, whereas CBF and CMR during deep sleep (stage III-IV) is dramatically reduced by 25-44%. Furthermore, recent data indicate that global levels of CBF and CMR are about the same during REM sleep as in wakefulness. On the regional level, deep sleep seems to be associated with a uniform decrease in regional CBF and CMR. Investigations concerning regional CBF and CMR during REM sleep are few but data from recent investigations seem to identify site-specific changes in regional CBF and CMR during REM sleep. CBF and CMR are reflections of cerebral synaptic activity and the magnitude of reduction in these variables associated with deep sleep indicates that overall cerebral synaptic activity is reduced to approximately one-half the level associated with wakefulness, while cerebral synaptic activity levels during REM sleep are similar to wakefulness. However, even though the new understanding of CBF and CMR during sleep provides significant and important information of the brain's mode of working during sleep, it does not at its current state identify the physiological processes involved in sleep or the physiological role of sleep.

  15. Intraoperative cerebral blood flow imaging of rodents

    Science.gov (United States)

    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.

  16. Cerebral blood-flow tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Holm, S;

    1983-01-01

    Tomographic maps of local cerebral blood flow (CBF) were obtained with xenon-133 and with isopropyl-amphetamine-iodine-123 (IMP) in 11 subjects: one normal, two tumor cases, and eight cerebrovascular cases. A highly sensitive four-face, rapidly rotating, single-photon emission tomograph was used......., and with low radiation exposure to patient and personnel. On the other hand, IMP gives an image of slightly higher resolution. It also introduces a new class of iodinated brain-seeking compounds allowing, perhaps, imaging of other functions more important than mere blood flow.......Tomographic maps of local cerebral blood flow (CBF) were obtained with xenon-133 and with isopropyl-amphetamine-iodine-123 (IMP) in 11 subjects: one normal, two tumor cases, and eight cerebrovascular cases. A highly sensitive four-face, rapidly rotating, single-photon emission tomograph was used...

  17. Autoregulation of cerebral blood flow in experimental focal brain ischemia.

    Science.gov (United States)

    Dirnagl, U; Pulsinelli, W

    1990-05-01

    The relationship between systemic arterial pressure (SAP) and neocortical microcirculatory blood-flow (CBF) in areas of focal cerebral ischemia was studied in 15 spontaneously hypertensive rats (SHRs) anesthetized with halothane (0.5%). Ischemia was induced by ipsilateral middle cerebral artery/common carotid artery occlusion and CBF was monitored continuously in the ischemic territory using laser-Doppler flowmetry during manipulation of SAP with I-norepinephrine (hypertension) or nitroprusside (hypotension). In eight SHRs not subjected to focal ischemia, we demonstrated that 0.5% halothane and the surgical manipulations did not impair autoregulation. Autoregulation was partly preserved in ischemic brain tissue with a CBF of greater than 30% of preocclusion values. In areas where ischemic CBF was less than 30% of preocclusion values, autoregulation was completely lost. Changes in SAP had a greater influence on CBF in tissue areas where CBF ranged from 15 to 30% of baseline (9% change in CBF with each 10% change in SAP) than in areas where CBF was less than 15% of baseline (6% change in CBF with each 10% change in SAP). These findings demonstrate that the relationship between CBF and SAP in areas of focal ischemia is highly dependent on the severity of ischemia. Autoregulation is lost in a gradual manner until CBF falls below 30% of normal. In areas without autoregulation, the slope of the CBF/SAP relationship is inversely related to the degree of ischemia.

  18. Patterns of regional cerebral blood flow in acute stroke

    DEFF Research Database (Denmark)

    Olsen, T S; Skriver, E B

    1981-01-01

    In a consecutive group of 56 stroke patients the regional cerebral blood flow was measured within 84 hours after stroke. A 254 multidetector scintillation camera and the intracarotid Xenon-133 injection method was used to study rCBF. Typical rCBF-patterns are described and compared to the findings...

  19. New insights into coupling and uncoupling of cerebral blood flow and metabolism in the brain

    OpenAIRE

    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...

  20. Regional cerebral blood flow in schizophrenics

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, J.; Ohta, Y.; Nakane, Y.; Mori, H.; Hirota, N.; Yonekura, M.

    1987-01-01

    The present study on schizophrenics dealt with the relationship of regional cerebral blood flow (rCBF) to age, disease duration, and treatment length with chlorpromazine hydrochloride (CPZ). Regional cerebral blood flow in 28 cerebral regions of interest was measured by iv injection of /sup 133/X in 54 schizophrenic patients and 39 healthy volunteers. Neither age nor dosage of CPZ significantly influenced rCBF. All patients, including 11 treated for a short period of time (6 months or less), were characterized by having a decreased rCBF over the whole cerebrum. Thirty-four patients treated for a long period of time (2 years or more) had a varied rCBF distribution in the left hemisphere, with the most predominant feature being the decrease in rCBF in the frontal lobe (i.e., hypofrontality); however, there was no linear correlation between rCBF and disease duration. A decreased rCBE in the right occipital region was seen in patients with paranoid schizophrenia, suggesting that manifestations of symptoms may depend on disturbed regions. These results suggest that cerebral dysfunction in schizophrenic patients may not be restricted to the frontal lobe, but cover the whole cerebrum, and that nonuniform dysfunction in various regions of the cerebrum, including the frontal lobe, may be involved in manifestations of symptoms.

  1. Laser Doppler flowmetry to measure changes in cerebral blood flow.

    Science.gov (United States)

    Sutherland, Brad A; Rabie, Tamer; Buchan, Alastair M

    2014-01-01

    Laser Doppler flowmetry (LDF) is a method by which relative cerebral blood flow (CBF) of the cortex can be measured. Although the method is easy to employ, LDF only measures relative CBF, while absolute CBF cannot be quantified. LDF is useful for investigating CBF changes in a number of different applications including neurovascular and stroke research. This chapter will prepare the reader for rodent experiments using LDF with two preparations. The closed skull preparation can be used to monitor CBF with an intact skull, but in adult rats, thinning of the skull is required to obtain an accurate cortical CBF signal. The open skull preparation requires a craniotomy to expose the surface of the brain and the LDF probe is held close to the surface to measure cerebral perfusion.

  2. A New Technology for Detecting Cerebral Blood Flow

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Guo, Song; Jensen, Lars T;

    2012-01-01

    There is a need for real-time non-invasive, continuous monitoring of cerebral blood flow (CBF) during surgery, in intensive care units and clinical research. We investigated a new non-invasive hybrid technology employing ultrasound tagged near infrared spectroscopy (UT-NIRS) that may estimate...... changes in CBF using a cerebral blood flow index (CFI). Changes over time for UT-NIRS CFI and (133)Xenon single photon emission computer tomography ((133)Xe-SPECT) CBF data were assessed in 10 healthy volunteers after an intravenous bolus of acetazolamide. UT-NIRS CFI was measured continuously and SPECT...

  3. Phase-Contrast Magnetic Resonance Angiography Measurements of Global Cerebral Blood Flow in the Neonate

    NARCIS (Netherlands)

    Benders, Manon J. N. L.; Hendrikse, Jeroen; de Vries, Linda S.; van Bel, Frank; Groenendaal, Floris

    2011-01-01

    Cerebral blood flow (CBF) alterations are important in pathogenesis of neonatal ischemic/hemorrhagic brain damage. In clinical practice, estimation of neonatal CBF is mostly based on Doppler-measured blood flow velocities in major intracranial arteries. Using phase-contrast magnetic resonance angiog

  4. Leg blood flow measurements using venous occlusion plethysmography during head-up tilt.

    NARCIS (Netherlands)

    Kooijman, M.; Poelkens, F.; Rongen, G.A.; Smits, P.; Hopman, M.T.E.

    2007-01-01

    We tested whether venous occlusion plethysmography (VOP) is an appropriate method to measure calf blood flow (CBF) during head-up tilt (HUT). CBF measured with VOP was compared with superficial femoral artery blood flow as measured by Doppler ultrasound during incremental tilt angles. Measurements o

  5. Simultaneous Imaging of CBF Change and BOLD with Saturation-Recovery-T1 Method.

    Science.gov (United States)

    Wang, Xiao; Zhu, Xiao-Hong; Zhang, Yi; Chen, Wei

    2015-01-01

    A neuroimaging technique based on the saturation-recovery (SR)-T1 MRI method was applied for simultaneously imaging blood oxygenation level dependence (BOLD) contrast and cerebral blood flow change (ΔCBF), which is determined by CBF-sensitive T1 relaxation rate change (ΔR1CBF). This technique was validated by quantitatively examining the relationships among ΔR1CBF, ΔCBF, BOLD and relative CBF change (rCBF), which was simultaneously measured by laser Doppler flowmetry under global ischemia and hypercapnia conditions, respectively, in the rat brain. It was found that during ischemia, BOLD decreased 23.1±2.8% in the cortical area; ΔR1CBF decreased 0.020±0.004s-1 corresponding to a ΔCBF decrease of 1.07±0.24 ml/g/min and 89.5±1.8% CBF reduction (n=5), resulting in a baseline CBF value (=1.18 ml/g/min) consistent with the literature reports. The CBF change quantification based on temperature corrected ΔR1CBF had a better accuracy than apparent R1 change (ΔR1app); nevertheless, ΔR1app without temperature correction still provides a good approximation for quantifying CBF change since perfusion dominates the evolution of the longitudinal relaxation rate (R1app). In contrast to the excellent consistency between ΔCBF and rCBF measured during and after ischemia, the BOLD change during the post-ischemia period was temporally disassociated with ΔCBF, indicating distinct CBF and BOLD responses. Similar results were also observed for the hypercapnia study. The overall results demonstrate that the SR-T1 MRI method is effective for noninvasive and quantitative imaging of both ΔCBF and BOLD associated with physiological and/or pathological changes.

  6. Simultaneous Imaging of CBF Change and BOLD with Saturation-Recovery-T1 Method.

    Directory of Open Access Journals (Sweden)

    Xiao Wang

    Full Text Available A neuroimaging technique based on the saturation-recovery (SR-T1 MRI method was applied for simultaneously imaging blood oxygenation level dependence (BOLD contrast and cerebral blood flow change (ΔCBF, which is determined by CBF-sensitive T1 relaxation rate change (ΔR1CBF. This technique was validated by quantitatively examining the relationships among ΔR1CBF, ΔCBF, BOLD and relative CBF change (rCBF, which was simultaneously measured by laser Doppler flowmetry under global ischemia and hypercapnia conditions, respectively, in the rat brain. It was found that during ischemia, BOLD decreased 23.1±2.8% in the cortical area; ΔR1CBF decreased 0.020±0.004s-1 corresponding to a ΔCBF decrease of 1.07±0.24 ml/g/min and 89.5±1.8% CBF reduction (n=5, resulting in a baseline CBF value (=1.18 ml/g/min consistent with the literature reports. The CBF change quantification based on temperature corrected ΔR1CBF had a better accuracy than apparent R1 change (ΔR1app; nevertheless, ΔR1app without temperature correction still provides a good approximation for quantifying CBF change since perfusion dominates the evolution of the longitudinal relaxation rate (R1app. In contrast to the excellent consistency between ΔCBF and rCBF measured during and after ischemia, the BOLD change during the post-ischemia period was temporally disassociated with ΔCBF, indicating distinct CBF and BOLD responses. Similar results were also observed for the hypercapnia study. The overall results demonstrate that the SR-T1 MRI method is effective for noninvasive and quantitative imaging of both ΔCBF and BOLD associated with physiological and/or pathological changes.

  7. Effect of pregnancy on regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Nagamachi, Shigeki; Hoshi, Hiroaki; Jinnouchi, Seishi; Ohnishi, Takashi; Futami, Shigemi; Watanabe, Katsushi; Ikeda, Tomoaki; Mori, Norimasa [Miyazaki Medical Coll., Kiyotake (Japan)

    1993-12-01

    Regional cerebral blood flow (r-CBF) of 10 pregnant women were quantified by {sup 133}Xe SPECT study with inhalation method before and after artificial abortion. During pregnancy, value of r-CBF in each region except occipital lobe was significantly higher than that of the post abortion. Arterial blood gas was analyzed after SPECT procedure. P{sub co2} concentration increased significantly after artificial abortion. Although its mechanism is unknown, our preliminary work demonstrates that r-CBF increased by pregnancy. (author).

  8. Tomographic cerebral blood flow measurement during carotid surgery

    DEFF Research Database (Denmark)

    Rathenborg, Lisbet Knudsen; Vorstrup, Sidsel; Olsen, K S

    1994-01-01

    OBJECTIVES: The aim of the study was to depict regional cerebral blood flow (rCBF) during carotid cross clamping using 99mTechnetium-hexamethylpropylene amine oxime (TcHMPAO). This tracer rapidly passes the blood-brain barrier and is retained for hours in the brain tissue. Injecting TcHMPAO during...... RESULTS: We found a significant correlation between stump pressure and enhancement of side-to-side asymmetry in rCBF due to carotid cross clamping. Pronounced variations were seen in which regions were deprived of perfusion during clamping. CONCLUSION: TcHMPAO allows tomographic assessment of CBF during...

  9. Carbon dioxide induced changes in cerebral blood flow and flow velocity: Role of cerebrovascular resistance and effective cerebral perfusion pressure

    NARCIS (Netherlands)

    F. Grüne (Frank); S. Kazmaier (Stephan); R.J. Stolker (Robert J.); G.H. Visser (Gerhard Henk); A. Weyland (Andreas)

    2015-01-01

    textabstractIn addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2 -induced changes in CBF, CVR,

  10. HIV and chronic methamphetamine dependence affect cerebral blood flow.

    Science.gov (United States)

    Ances, Beau M; Vaida, Florin; Cherner, Mariana; Yeh, Melinda J; Liang, Christine L; Gardner, Carly; Grant, Igor; Ellis, Ronald J; Buxton, Richard B

    2011-09-01

    Human immunodeficiency virus (HIV) and methamphetamine (METH) dependence are independently associated with neuronal dysfunction. The coupling between cerebral blood flow (CBF) and neuronal activity is the basis of many task-based functional neuroimaging techniques. We examined the interaction between HIV infection and a previous history of METH dependence on CBF within the lenticular nuclei (LN). Twenty-four HIV-/METH-, eight HIV-/METH+, 24 HIV+/METH-, and 15 HIV+/METH+ participants performed a finger tapping paradigm. A multiple regression analysis of covariance assessed associations and two-way interactions between CBF and HIV serostatus and/or previous history of METH dependence. HIV+ individuals had a trend towards a lower baseline CBF (-10%, p = 0.07) and greater CBF changes for the functional task (+32%, p = 0.01) than HIV- subjects. Individuals with a previous history of METH dependence had a lower baseline CBF (-16%, p = 0.007) and greater CBF changes for a functional task (+33%, p = 0.02). However, no interaction existed between HIV serostatus and previous history of METH dependence for either baseline CBF (p = 0.53) or CBF changes for a functional task (p = 0.10). In addition, CBF and volume in the LN were not correlated. A possible additive relationship could exist between HIV infection and a history of METH dependence on CBF with a previous history of METH dependence having a larger contribution. Abnormalities in CBF could serve as a surrogate measure for assessing the chronic effects of HIV and previous METH dependence on brain function.

  11. Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise

    DEFF Research Database (Denmark)

    Madsen, P L; Sperling, B K; Warming, T

    1993-01-01

    Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions....... To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity...... in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P

  12. [Measurement of cerebral blood flow using phase-contrast MRI].

    Science.gov (United States)

    Obata, T; Shishido, F; Koga, M; Ikehira, H; Kimura, F; Yoshida, K

    1997-07-01

    The development of phase-contrast magnetic resonance imaging(P-C MRI) provides a noninvasive method for measurement of volumetric blood flow(VFR). The VFR of the left and right internal carotid arteries and basilar artery were measured using P-C MRI, and total cerebral blood flow(tCBF) was calculated by summing up the VFR values in three vessels. We investigated the changes in these blood flows as influenced from age, head size, height, weight, body surface area and handedness. Moreover, regional CBF(rCBF) was measured by combining with the single photon emission computed tomography(SPECT) of 123I. The blood flows were 142 +/- 58 mL/ min(mean +/- SD) in the basilar artery, 229 +/- 86 mL/min in the left, 223 +/- 58 mL/min in the right internal carotid artery, and tCBF was 617 +/- 128 mL/min(Ref. Magn Resn Imaging 14:P. 1143, 1996). Significant increases were observed in head-size-related change of VFR in the basilar artery and height-related change of tCBF. The value of rCBF was easily acquired in combination with SPECT. Phase-contrast MRI is useful for a noninvasive and rapid analysis of cerebral VFR and has potential for clinical use.

  13. Peculiarities of Brain's Blood Flow : Role of Carbon Dioxide

    CERN Document Server

    Gersten, Alexander

    2011-01-01

    Among the major factors controlling the cerebral blood flow (CBF), the effect of PaCO2 is peculiar in that it violates autoregulatory CBF mechanisms and allows to explore the full range of the CBF. This research resulted in a simple physical model, with a four parameter formula, relating the CBF to PaCO2. The parameters can be extracted in an easy manner, directly from the experimental data. With this model earlier experimental data sets of Rhesus monkeys and rats were well fitted. Human data were also fitted with this model. Exact formulae were found, which can be used to transform the fits of one animal to the fits of another one. The merit of this transformation is that it enable us the use of rats data as monkeys data simply by rescaling the PaCO2 values and the CBF data. This transformation makes possible the use of experimental animal data instead of human ones.

  14. Pre- and postoperative changes of regional cortical cerebral blood flow in patients with cerebral arteriovenous malformation

    Institute of Scientific and Technical Information of China (English)

    石广志; 赵继宗; 王硕; 王永刚; 陆铮

    2003-01-01

    Objective To investigate pre- and postoperative changes of regional cerebral cortical blood flow in patients with cerebral arteriovenous malformation. Method Twenty-two adult patients with arteriovenous malformation(AVM) were recruited into this study at Beijing Tiantan Hospital from September 2001 to May 2002. Eight patients had giant cerebral AVM and the other 14 had a small one. Cortical cerebral blood flow (CBF) was measured by laser Doppler flowmetry (LDF) before and after AVM resections. After surgery, the probe of LDF was implanted adjacent to the area of AVM and monitored for 24 hours.Results CBF increased significantly after the resection in all patients regardless of AVM size. In patients with small AVM, CBF returned to the baseline level within 4 hours, but in patients with giant AVM, CBF remained high even after 24 hours.Conclusions Monitoring CBF is helpful to understand pre- and postoperative changes of regional cortical CBF in patients with cerebral AVM.

  15. Sources of variability of resting cerebral blood flow in healthy subjects

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Kruuse, Christina Rostrup; Olesen, Jes

    2013-01-01

    when Hct was also accounted for. The present study confirms large between-subject variability in CBF measurements and that gender, Hct, and PETCO2 explain only a small part of this variability. This implies that a large fraction of CBF variability may be due to unknown factors such as differences......Measurements of cerebral blood flow (CBF) show large variability among healthy subjects. The aim of the present study was to investigate the relative effect of established factors influencing CBF on the variability of resting CBF. We retrospectively analyzed spontaneous variability in 430 CBF...... measurements acquired in 152 healthy, young subjects using (133)Xe single-photon emission computed tomography. Cerebral blood flow was correlated positively with both end-tidal expiratory PCO2 (PETCO2) and female gender and inversely with hematocrit (Hct). Between- and within-subject CO2 reactivity...

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

    Science.gov (United States)

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

    2015-12-01

    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.

  17. Cerebral blood flow in patients with dementia of Alzheimer's type

    DEFF Research Database (Denmark)

    Postiglione, A; Lassen, N A; Holman, B L

    1993-01-01

    In the normal brain as well as in Alzheimer's disease (AD), regional cerebral blood flow (CBF) is coupled to metabolic demand and, therefore, changes in CBF reflect variations in neuronal metabolism. The use of radionuclide techniques, such as positron emission tomography (PET) and single photon...... of the disease. Lateral CBF asymmetry is also very frequent; speech disorders are highly characteristic of left-sided flow reduction, while visuospatial apraxia is dominating in the right-sided cases. In advanced and severe cases of AD, CBF and metabolism tend to be more uniformly reduced throughout the cortex......, sparing only the primary visual and sensory-motor cortices. PET and SPECT measurement of brain perfusion and metabolism has added a new dimension to the knowledge of dementia disorders, with a better differential diagnosis between AD and other forms of dementia. The correlation with neuropsychological...

  18. Cognitive profiles and regional cerebral blood flow patterns in dementia of the Alzheimer type

    DEFF Research Database (Denmark)

    Waldemar, G; Bruhn, P; Schmidt, E

    1994-01-01

    Individual cognitive profiles and correlations between cognitive functions and regional cerebral blood flow (rCBF) were analyzed in 20 consecutive patients with a clinical diagnosis of probable Alzheimer's disease (AD). CBF was measured with high resolution single photon emission computed...

  19. Cerebral blood flow and metabolism in adults with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten

    2007-01-01

    The intense intrathecal inflammation observed in acute bacterial meningitis (ABM) is associated with pronounced changes in cerebral blood flow (CBF) and metabolism. In seven substudies, CBF and metabolism were measured in adults with ABM as well as healthy volunteers during various interventions...

  20. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR...

  1. Cerebral white matter blood flow and energy metabolism in multiple sclerosis

    NARCIS (Netherlands)

    Steen, Christel; D'haeseleer, Miguel; Hoogduin, Johannes M.; Fierens, Yves; Cambron, Melissa; Mostert, Jop P.; Heersema, Dorothea J.; Koch, Marcus W.; De Keyser, Jacques

    2013-01-01

    Background: Cerebral blood flow (CBF) is reduced in normal-appearing white matter (NAWM) of subjects with multiple sclerosis (MS), but the underlying mechanism is unknown. Objective: The objective of this article is to assess the relationship between reduced NAWM CBF and both axonal mitochondrial me

  2. Regional cerebral blood flow during mechanical hyperventilation in patients with fulminant hepatic failure

    DEFF Research Database (Denmark)

    Strauss, Gitte Irene; Høgh, Peter; Møller, Kirsten;

    1999-01-01

    Hyperventilation is frequently used to prevent or postpone the development of cerebral edema and intracranial hypertension in patients with fulminant hepatic failure (FHF). The influence of such therapy on regional cerebral blood flow (rCBF) remains, however, unknown. In this study the CBF...

  3. A pilot study of regional cerebral blood flow in children with school phobia

    Institute of Scientific and Technical Information of China (English)

    钱昀

    2006-01-01

    Objective To explore the characteristics of the regional cerebral blood flow (rCBF) in children with school phobia. Methods The single - photon emission commputed tomography were performed in 17 children with school phobia and 11 normal controls. The rCBF distribution in regions of interest (ROIs) was compared

  4. The effect of the benzodiazepine antagonist flumazenil on regional cerebral blood flow in human volunteers

    DEFF Research Database (Denmark)

    Wolf, J; Friberg, L; Jensen, J

    1990-01-01

    The influence of the benzodiazepine antagonist flumazenil on regional cerebral blood flow (rCBF) was investigated in ten healthy, alert volunteers. The design was a randomized, placebo-controlled, double-blind, cross-over study. rCBF was measured by 133-Xe inhalation and single photon emission...

  5. Cerebral blood flow measurement using fMRI and PET: a cross-validation study.

    Science.gov (United States)

    Chen, Jean J; Wieckowska, Marguerite; Meyer, Ernst; Pike, G Bruce

    2008-01-01

    An important aspect of functional magnetic resonance imaging (fMRI) is the study of brain hemodynamics, and MR arterial spin labeling (ASL) perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF) measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (DeltaCBF) measured using a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion method to those obtained using H(2) (15)O PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI) masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity). Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

  6. Cerebral Blood Flow Measurement Using fMRI and PET: A Cross-Validation Study

    Directory of Open Access Journals (Sweden)

    Jean J. Chen

    2008-01-01

    Full Text Available An important aspect of functional magnetic resonance imaging (fMRI is the study of brain hemodynamics, and MR arterial spin labeling (ASL perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (ΔCBF measured using a flow-sensitive alternating inversion recovery (FAIR ASL perfusion method to those obtained using H2O15 PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average ΔCBF of 21.5±8.2% for FAIR versus 28.2±12.8% for PET at maximum stimulation intensity. Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL ΔCBF for all 3 ROI types indicated no significant difference from unity (P>.05.

  7. Cerebral blood flow and oxidative metabolism during human endotoxemia

    DEFF Research Database (Denmark)

    Møller, Kirsten; Strauss, Gitte Irene; Qvist, Jesper;

    2002-01-01

    The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), has been suggested to mediate septic encephalopathy through an effect on cerebral blood flow (CBF) and metabolism. The effect of an intravenous bolus of endotoxin on global CBF, metabolism, and net flux of cytokines...... and catecholamines was investigated in eight healthy young volunteers. Cerebral blood flow was measured by the Kety-Schmidt technique at baseline (during normocapnia and voluntary hyperventilation for calculation of subject-specific cerebrovascular CO reactivity), and 90 minutes after an intravenous bolus...

  8. Hemoglobin, hematocrit, and changes in cerebral blood flow : The Second Manifestations of ARTerial disease-Magnetic Resonance study

    NARCIS (Netherlands)

    van der Veen, Pieternella H.; Muller, Majon; Vincken, Koen L.; Westerink, Jan; Mali, Willem P. T. M.; van der Graaf, Yolanda; Geerlings, Mirjam I.; Doevendans, PAFM

    2015-01-01

    Hemoglobin and hematocrit are important determinants of blood viscosity and arterial oxygen content and may therefore influence cerebral blood flow (CBF). We examined cross-sectional and prospective associations of hemoglobin and hematocrit with CBF in 569 patients with manifest arterial disease (me

  9. Brain energy metabolism and blood flow differences in healthy aging

    DEFF Research Database (Denmark)

    Aanerud, Joel; Borghammer, Per; Chakravarty, M Mallar

    2012-01-01

    Cerebral metabolic rate of oxygen consumption (CMRO(2)), cerebral blood flow (CBF), and oxygen extraction fraction (OEF) are important indices of healthy aging of the brain. Although a frequent topic of study, changes of CBF and CMRO(2) during normal aging are still controversial, as some authors...... find decreases of both CBF and CMRO(2) but increased OEF, while others find no change, and yet other find divergent changes. In this reanalysis of previously published results from positron emission tomography of healthy volunteers, we determined CMRO(2) and CBF in 66 healthy volunteers aged 21 to 81......, and in the temporal cortex. Because of the inverse relation between OEF and capillary oxygen tension, increased OEF can compromise oxygen delivery to neurons, with possible perturbation of energy turnover. The results establish a possible mechanism of progression from healthy to unhealthy brain aging, as the regions...

  10. Quantitative measurement of cerebral blood flow on patients with early syphilis

    Institute of Scientific and Technical Information of China (English)

    ZHONG Ji-Jun; WU Jin-Chang; YANG Yi; TANG Jun; LIU Zeng-Li; SHI Xin

    2005-01-01

    To study quantitative change of cerebral blood flow (CBF) on patients with early syphilis, we have established a method on absolute measurement of rCBF by using SPECT with Ethyl Cysteinate Dimmer (ECD) as imaging agent, and the method was applied to measure rCBF on patients with early syphilis. The rCBF values measured by this method are highly consistent with the values measured by other classical methods such as SPECT (123I-IMP) and PET (15O-H2O). The rCBF values for early syphilis patients and the normal control show some statistical differences.A routine quantitative absolute measurement of rCBF featured with simple procedures is therefore on the way of maturation.

  11. Fibro-Vascular Coupling in the Control of Cochlear Blood Flow

    OpenAIRE

    Min Dai; Xiaorui Shi

    2011-01-01

    BACKGROUND: Transduction of sound in the cochlea is metabolically demanding. The lateral wall and hair cells are critically vulnerable to hypoxia, especially at high sound levels, and tight control over cochlear blood flow (CBF) is a physiological necessity. Yet despite the importance of CBF for hearing, consensus on what mechanisms are involved has not been obtained. METHODOLOGY/PRINCIPAL FINDINGS: We report on a local control mechanism for regulating inner ear blood flow involving fibrocyte...

  12. Relationship between cardiac function and resting cerebral blood flow

    DEFF Research Database (Denmark)

    Henriksen, Otto M; Jensen, Lars T; Krabbe, Katja;

    2014-01-01

    Although both impaired cardiac function and reduced cerebral blood flow are associated with ageing, current knowledge of the influence of cardiac function on resting cerebral blood flow (CBF) is limited. The aim of this study was to investigate the potential effects of cardiac function on CBF. CBF...... and cardiac output were measured in 31 healthy subjects 50-75 years old using magnetic resonance imaging techniques. Mean values of CBF, cardiac output and cardiac index were 43.6 ml per 100 g min(-1), 5.5 l min(-1) and 2.7 l min(-1) m(-2), respectively, in males, and 53.4 ml per 100 g min(-1), 4.3 l min(-1......) and 2.4 l min(-1) m(-2), respectively, in females. No effects of cardiac output or cardiac index on CBF or structural signs of brain ageing were observed. However, fractional brain flow defined as the ratio of total brain flow to cardiac output was inversely correlated with cardiac index (r(2) = 0.22, P...

  13. Changes in regional cerebral blood flow during the course of classic migraine attacks

    DEFF Research Database (Denmark)

    Lauritzen, M; Skyhøj Olsen, T; Lassen, N A

    1983-01-01

    and were examined by a series of rCBF studies, spaced by intervals of 5 to 10 minutes. A wave of reduced blood flow originating in the posterior part of the brain and progressing anteriorly was observed in eight of the nine patients. The oligemia advanced at a speed of 2 mm per minute over the hemisphere......Regional cerebral blood flow (rCBF) following carotid arteriography was studied in thirteen patients with classic migraine. Using the 133xenon intraarterial injection method, rCBF was measured in 254 areas in one hemisphere. Nine patients developed a characteristic attack following arteriography...

  14. Cerebral blood flow tomography with xenon-133

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Regional cerebral blood flow in normal pressure hydrocephalus: diagnostic and prognostic aspects

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, A. (Dept. of Neurology, Sahlgren Hospital, Goeteborg (Sweden)); Bergh, A.C. (Dept. of Clinical Physiology, Sahlgren Hospital, Goeteborg (Sweden)); Bilting, M. (Dept. of Neurosurgery, Sahlgren Hospital, Goeteborg (Sweden)); Aerlig, AA. (Dept. of Radiation Physics, Sahlgren Hospital, Goeteborg (Sweden)); Jacobsson, L. (Dept. of Radiation Physics, Sahlgren Hospital, Goeteborg (Sweden)); Stephensen, H. (Dept. of Neurosurgery, Sahlgren Hospital, Goeteborg (Sweden)); Wikkelsoe, C. (Dept. of Neurology, Sahlgren Hospital, Goeteborg (Sweden))

    1994-02-01

    Relative regional cerebral blood flow (rrCBF) was measured by SPET using [sup 99m]Tc-HMPAO as flow tracer, in 23 patients with normal pressure hydrocephalus (NPH). 1000 MBq [sup 99m]Tc-HMPAO was given intravenously and the rrCBF calculated as regional/cerebellar count level ratios. The patients were examined before and 3-12 months after ventriculoperitoneal shunt surgery. rrCBF was also determined in ten healthy aged matched volunteers who served as controls. The NPH patients had decreased rrCBF in the hippocampal regions and in the frontal and parietal white matter as compared to the controls. The frontal/parietal rrCBF ratio correlated with both psychiatric disability and the preoperative degree of incontinence. Decreased flow in frontal white matter, frontoparietal and hippocampal grey matter and a low frontalparietal grey matter flow ratio preoperatively correlated with improvement in both Mini Mental State score and psychiatric disability after shunt surgery. After shunt surgery the rrCBF increased in the mesencephalon, frontal grey and white matter, parietal white matter and hippocampus. The flow increase in hippocampal regions and frontal white matter correlated with improvement in psychiatric symptomatology. The results of this study regarding the frontal and hippocampal rrCBF patterns, and the clinical correlation, support the hypothesis that CBF changes in these regions are of patohphysiological and prognostic importance in NPH. (orig./MG)

  16. Effects of cigarette smoking on cerebral blood flow in normal adults

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, Takao [Tokyo Medical Coll. (Japan)

    1997-11-01

    To elucidate the pharmacological effects of cigarette smoking on cerebral function and blood flow in normal adults, cerebral blood flow (CBF) was measured by positron emission tomography (PET) in 10 right-handed male healthy volunteers with a smoking habit after 12-hour abstinence. By the oxygen-15 intravenous injection method, quantitative CBF was measured repeatedly 6 times; during normal breathing (baseline), 5% CO{sub 2} inhalation and cigarette smoking. Sham smoking was performed during baseline and CO{sub 2} inhalation. To eliminate the effects from PaCO{sub 2}, CBF was adjusted based on the vascular reactivity to CO{sub 2} and PaCO{sub 2} during smoking. Pulse rate, systemic blood pressure and arterial nicotine level were increased during smoking. In the overall comparison, there was no significant change in the mean CBF during smoking as compared with baseline. Out of 19 sessions, CBF increased significantly in 7 sessions, while CBF decreased in 7 sessions and was unchanged in 5 sessions. The arterial concentration of nicotine correlated inversely with CBF. When the baseline CBF was relatively low, CBF increased during smoking, while it decreased when the baseline value was high. In the 3-dimensional statistical analysis of normalized CBF, a significant increase was seen in the nucleus accumbens, which is assumed to be related to the drug habits or addiction in previous studies. In the first smoking after abstinence, CBF increased in the orbitofrontal gyri, and this can be linked to reward or relaxation. By contrast, a significant decrease was observed in the occipital lobes and paracentral areas. (author)

  17. Continuous monitoring of absolute cerebral blood flow by combining diffuse correlation spectroscopy and time-resolved near-infrared technology

    Science.gov (United States)

    Diop, Mamadou; Lee, Ting-Yim; St. Lawrence, Keith

    2011-02-01

    Continuous bedside monitoring of cerebral blood flow (CBF) in patients recovering from brain injury could improve the detection of impaired substrate delivery, which can exacerbate injury and worsen outcome. Diffuse correlation spectroscopy (DCS) provides the ability to monitor perfusion changes continuously, but it is difficult to quantify absolute blood flow - leading to uncertainties as to whether or not CBF has fallen to ischemic levels. To continuously measure CBF, we propose to calibrate DCS data using a single time-point, time-resolved near-infrared (TR-NIR) technique for measuring absolute CBF. Experiments were conducted on newborn piglets in which CBF was increased by raising the arterial tension of CO2 (40-62 mmHg) and decreased by carotid occlusion. For validation, values of CBF measured by TR-NIR were converted into blood flow changes and compared to CBF changes measured by DCS. A strong correlation between perfusion changes from the two techniques was revealed (slope = 0.98 and R2 = 0.96), suggesting that a single time-point CBF measurement by TR-NIR can be used to convert continuous DCS data into units of CBF (ml/100g/min).

  18. Clinical studies of cerebral circulation using single photon emission computed tomography, 2; Evaluation of cerebral blood flow after acetazolamide loading on moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Toshiro [Gifu Univ. (Japan). Faculty of Medicine

    1993-09-01

    To evaluate cerebral blood flow (CBF) in patients with moyamoya disease, single photon emission computed tomography (SPECT) was performed using acetazolamide-activated {sup 133}Xe inhalation method. In the present investigation, 15 patients were subjected: 6 pediatric cases with the mean age of 10.8 years and 9 adult cases with the mean age of 44.6 years. The regional CBF (rCBF) was measured in the territory of anterior cerebral artery (ACA), middle cerebral artery (MCA), posterior cerebral artery (PCA), basal ganglia, and cerebellum. Cerebrovascular acetazolamide reactivity was evaluated from the rCBF measured before and after administration of acetazolamide. Namely, cerebrovascular acetazolamide reactivity was expressed as %CBF and calculated as follows: %CBF=100 x (CBF after acetazolamide administration-CBF at rest)/CBF at rest. rCBF in adult patients was decreased in the cerebral hemisphere, while that in childhood was significantly decreased in the territory of ACA. The %CBF after acetazolamide loading was decreased in the territory of ACA and MCA in both adult and childhood. When cerebral %CBF was compared to the cerebellar %CBF, the ratio of cerebral %CBF and cerebellar %CBF resulted in markedly lower in childhood than adult. rCBF and cerebrovascular acetazolamide reactivity were also measured before and after extracranial and intracranial (EC-IC) bypass surgery in three pediatric moyamoya patients. Although rCBF was increased immediately after EC-IC bypass surgery, the cerebrovascular acetazolamide reactivity remained blunted. These results meant that in the pediatric moyamoya patients cerebrovascular acetazolamide reactivity is more blunted than adult moyamoya patients. Also, the cerebral vessels in moyamoya disease were considered to be dilated to their limitation by the blood supplied through the EC-IC bypass and not to be expandable any more by acetazolamide. (author) 45 refs.

  19. Unveiling astrocytic control of cerebral blood flow with optogenetics.

    Science.gov (United States)

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

    2015-06-16

    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.

  20. Cerebral blood flow and carbon dioxide reactivity in children with bacterial meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Ashwal, S.; Stringer, W.; Tomasi, L.; Schneider, S.; Thompson, J.; Perkin, R. (Loma Linda Univ. School of Medicine, CA (USA))

    1990-10-01

    We examined total and regional cerebral blood flow (CBF) by stable xenon computed tomography in 20 seriously ill children with acute bacterial meningitis to determine whether CBF was reduced and to examine the changes in CBF during hyperventilation. In 13 children, total CBF was normal (62 +/- 20 ml/min/100 gm) but marked local variability of flow was seen. In five other children, total CBF was significantly reduced (26 +/- 10 ml/min/100 gm; p less than 0.05), with flow reduced more in white matter (8 +/- 5 ml/min/100 gm) than in gray matter (30 +/- 15 ml/min/100 gm). Autoregulation of CBF appeared to be present in these 18 children within a range of mean arterial blood pressure from 56 to 102 mm Hg. In the remaining two infants, brain dead within the first 24 hours, total flow was uniformly absent, averaging 3 +/- 3 ml/min/100 gm. In seven children, CBF was determined at two carbon dioxide tension (PCO2) levels: 40 (+/- 3) mm Hg and 29 (+/- 3) mm Hg. In six children, total CBF decreased 33%, from 52 (+/- 25) to 35 (+/- 15) ml/min/100 gm; the mean percentage of change in CBF per millimeter of mercury of PCO2 was 3.0%. Regional variability of perfusion to changes in PCO2 was marked in all six children. The percentage of change in CBF per millimeter of mercury of PCO2 was similar in frontal gray matter (3.1%) but higher in white matter (4.5%). In the seventh patient a paradoxical response was observed; total and regional CBF increased 25% after hyperventilation. Our findings demonstrate that (1) CBF in children with bacterial meningitis may be substantially decreased globally, with even more variability noted regionally, (2) autoregulation of CBF is preserved, (3) CBF/CO2 responsitivity varies among patients and in different regions of the brain in the same patient, and (4) hyperventilation can reduce CBF below ischemic thresholds.

  1. Alterations of Regional Cerebral Blood Flow in Major Depressive Disorder

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Hyoung; Chung, Yong An; Seo, Ye Young; Yoo, Ik Dong; Na, Sae Jung; Jung, Hyun Suk; Kim, Ki Jun [College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2009-04-15

    The authors analyzed how the regional cerebral blood flow (rCBF) findings of patients with major depression differ from the normal control, and our results were compared to previous reports. Twelve patients fulfilling DSM-IV criteria for major depression who were off all psychotropic medications for > 4 weeks (male: 7, female: 5, age range: 19approx52 years, average age: 29.3+-9.9 years) and 14 normal volunteers (male: 8, female: 6, age range: 19approx53 years, average age: 31.4+-9.2 years) were recruited. Images of brain perfusion SPECT were obtained using Tc-99m ECD and patterns of the rCBF were compared between patients with major depression and the healthy control subjects. The patients with major depression showed increase of the r-CBF in right lingual gyrus, right fusiform gyrus, left lingual gyrus, left precuneus, and left superior temporal gyrus, and showed decrease of r-CBF in right pons, left medial frontal gyrus, cingulate gyrus of left limbic lobe, cingulate gyrus of right frontal lobe, and cingulate gyrus of right limbic lobe compared to the normal control. The Tc-99m ECD brain perfusion SPECT findings in our study did not differ from the previously reported regional cerebral blood flow pattern of patients with major depression. Especially, decreased rCBF pattern typical to major depression patients in the right pons, left medial frontal gyrus, and cingulate regions was clearly demonstrated

  2. Determination of relative CMRO2 from CBF and BOLD changes: significant increase of oxygen consumption rate during visual stimulation

    DEFF Research Database (Denmark)

    Kim, S.G.; Rostrup, Egill; Larsson, H.B.;

    1999-01-01

    The blood oxygenation level-dependent (BOLD) effect in functional magnetic resonance imaging depends on at least partial uncoupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) changes. By measuring CBF and BOLD simultaneously, the relative change in CMRO2 can b...

  3. Focal ischaemia caused by instability of cerebrovascular tone during attacks of hemiplegic migraine. A regional cerebral blood flow study

    DEFF Research Database (Denmark)

    Friberg, L; Olsen, T S; Roland, P E

    1987-01-01

    During the course of hemiplegic migraine in 3 patients, changes in regional cerebral blood flow (rCBF) were recorded by the intracarotid 133Xe method and a 254 multidetector camera covering one hemisphere. The rCBF measurements were performed in conjunction with cerebral angiography. During...

  4. Electrical modulation of the sympathetic nervous system in order to augment cerebral blood flow : a protocol for an experimental study

    NARCIS (Netherlands)

    Ter Laan, Mark; van Dijk, J. Marc C.; Staal, Michiel J.; Elting, Jan-Willem J.

    2011-01-01

    Introduction: Cerebral blood flow (CBF) is regulated by several mechanisms. Neurogenic control has been a matter of debate, even though several publications reported the effects of changes in sympathetic tone on CBF. Transcutaneous electrical nerve stimulation and spinal-cord stimulation have been s

  5. Cerebral blood flow autoregulation in experimental liver failure

    DEFF Research Database (Denmark)

    Dethloff, T.J.; Larsen, F.S.; Knudsen, Gitte Moos

    2008-01-01

    Patients with acute liver failure (ALF) display impairment of cerebral blood flow (CBF) autoregulation, which may contribute to the development of fatal intracranial hypertension, but the pathophysiological mechanism remains unclear. In this study, we examined whether loss of liver mass causes...... impairment of CBF autoregulation. Four rat models were chosen, each representing different aspects of ALF: galactosamine (GlN) intoxication represented liver necrosis, 90% hepatectomy (PHx90) represented reduction in liver mass, portacaval anastomosis (PCA) represented shunting of blood....../toxins into the systemic circulation thus mimicking intrahepatic shunting in ALF, PCA+NH(3) provided information about the additional effects of hyperammonemia Rats were intubated and sedated with pentobarbital. We measured CBF with laser Doppler, intracranial pressure (ICP) was measured in the fossa posterior...

  6. Regional cerebral blood flow during the auditory oddball task measured by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Mochida, Masahiko [Kyorin Univ., Mitaka, Tokyo (Japan). Graduate School of Medicine

    1997-03-01

    Regional cerebral blood flow (rCBF) was measured by employing PET in nine healthy right-handed male subjects, while they simultaneously performed the auditory oddball task using tone bursts. Results showed that the rCBF value was highest in the transverse gyrus of Heschl in both right and left hemispheres. When comparing the rCBF values between right and left hemispheres, four areas had higher rCBF values in the left hemisphere and eight areas had higher rCBF values in the right hemisphere. Of these, the anterior and posterior parts of the superior temporal gyrus, especially, showed significant differences. The hemispheric differences in the rCBF values of the auditory areas can be attributed to the performance of the oddball task which requires higher processing of non verbal auditory input. The P300 amplitude which reflects the amount of the allocated information processing resources correlated positively with rCBF in the following areas: left piriform cortex, the transverse gyrus of Heschl in both left and right hemispheres. Mean-while, P300 amplitude correlated negatively with rCBF in the nucleus accumbens septi in both right and left hemispheres. The N100 amplitude evoked by frequent stimulus did not correlate with rCBF in almost all ROIs. (K.H.)

  7. Mean arterial pressure change associated with cerebral blood flow in healthy older adults.

    Science.gov (United States)

    Deverdun, Jeremy; Akbaraly, Tasnime N; Charroud, Celine; Abdennour, Meriem; Brickman, Adam M; Chemouny, Stephane; Steffener, Jason; Portet, Florence; Bonafe, Alain; Stern, Yaakov; Ritchie, Karen; Molino, François; Le Bars, Emmanuelle; Menjot de Champfleur, Nicolas

    2016-10-01

    We investigate over a 12-year period the association between regional cerebral blood flow (CBF) and cardiovascular risk factors in a prospective cohort of healthy older adults (81.96 ± 3.82 year-old) from the Cognitive REServe and Clinical ENDOphenotype (CRESCENDO) study. Cardiovascular risk factors were measured over 12 years, and gray matter CBF was measured at the end of the study from high-resolution magnetic resonance imaging using arterial spin labeling. The association between cardiovascular risk factors, their long-term change, and CBF was assessed using multivariate linear regression models. Women were observed to have higher CBF than men (p < 0.05). Increased mean arterial pressure (MAP) over the 12-year period was correlated with a low cerebral blood flow (p < 0.05, R(2) = 0.21), whereas no association was detected between CBF and MAP at the time of imaging. High levels of glycemia tended to be associated with low cerebral blood flow values (p < 0.05). Age, alcohol consumption, smoking status, body mass index, history of cardiovascular disease, and hypertension were not associated with CBF. Our main result suggests that change in MAP is the most significant predictor of future CBF in older adults.

  8. Effect of intravenous infusion of iodinated contrast media on the coronary blood flow in dogs

    OpenAIRE

    Abd, Thura T; Asim I. Shafique; Hayder S. Yasir; Jung-Hee Seo; George, Richard T.; Rajat Mittal; Lardo, Albert C.

    2016-01-01

    Background: Coronary computed tomography angiography (CCTA) is obtained using peripheral intravenous iodinated contrast agents (ICA) injection. There is continuing attempts to derive coronary physiological information like coronary blood flow (CBF) and/or fractional flow reserve from CCTA images. However, no data is available regarding the effect of peripheral intravenous injection of ICA on CBF. Methods: A series of 4 experiments was performed using healthy mongrel dogs. All dogs underwen...

  9. Metabolic control of resting hemispheric cerebral blood flow is oxidative, not glycolytic

    OpenAIRE

    Powers, William. J.; Videen, Tom O.; Markham, Joanne; Walter, Vonn; Perlmutter, Joel S.

    2011-01-01

    Although the close regional coupling of resting cerebral blood flow (CBF) with both cerebral metabolic rate of oxygen (CMRO2) and cerebral metabolic rate of glucose (CMRglc) within individuals is well documented, there are few data regarding the coupling between whole brain flow and metabolism among different subjects. To investigate the metabolic control of resting whole brain CBF, we performed multivariate analysis of hemispheric CMRO2, CMRglc, and other covariates as predictors of resting ...

  10. Cerebral blood flow in migraine and cortical spreading depression

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, M.

    1987-01-01

    In a series of migraine patients, carotid arteriography was carried out as part of the clinical evalution. Nine patients developed a migrainous attack with focal neurological symptoms and headache after the angiography and during the subsequent, ongoing regional cerebral blood flow rCBF study. rCBF was measured by bolus injection of Xenon/sup 133/ into the internal carotid artery and a gamma camera with 254 collimated scintillation detectors covering the lateral aspect of the hemisphere. This technique depicts rCBF mainly at the level of the superficial cortex, with no depth resolution. The resolution is 1 cm/sup 2/ providing detailed spatial information of the cortical blood flow. Other methods for measuring local blood flow in animal and man employ a radioactive, freely diffusible tracer, in combination with an autoradiographic technique for the assessment of the tissue concentration, the so-called autoradiographic methods. In the series of patients with spontaneous migraine, rCBF was estimated using an in-vivo application of the autoradiographic principle. Xenon/sup 133/ was administered by inhalation and the time course of the arterial concentration curve was assessed by a scintillation detector over the upper right lung, since the arterial curve has been found to follow the shape of the lung curve. The rCBF was studied accompanying cortical spreading depression in rat experiments to evaluate wheter this phenomenon could explain the blood flow changes in migraine. (/sup 14/C) iodoantipyrine was given as an intravenous bolus injection and the brain content of indicator was determined by tissue sample or autoradiography after 10 or 20 seconds of isotope circulation. The conditions of the autoradiographic methods are that the flow remains constant within the period of measuring, and that the region under study is homogenous with regard to flow and lambda. (EG).

  11. The effect of isovolemic hemodilution with oxycyte, a perfluorocarbon emulsion, on cerebral blood flow in rats.

    Directory of Open Access Journals (Sweden)

    Zhong-jin Yang

    Full Text Available BACKGROUND: Cerebral blood flow (CBF is auto-regulated to meet the brain's metabolic requirements. Oxycyte is a perfluorocarbon emulsion that acts as a highly effective oxygen carrier compared to blood. The aim of this study is to determine the effects of Oxycyte on regional CBF (rCBF, by evaluating the effects of stepwise isovolemic hemodilution with Oxycyte on CBF. METHODOLOGY: Male rats were intubated and ventilated with 100% O(2 under isoflurane anesthesia. The regional (striatum CBF (rCBF was measured with a laser doppler flowmeter (LDF. Stepwise isovolemic hemodilution was performed by withdrawing 4ml of blood and substituting the same volume of 5% albumin or 2 ml Oxycyte plus 2 ml albumin at 20-minute intervals until the hematocrit (Hct values reached 5%. PRINCIPAL FINDINGS: In the albumin-treated group, rCBF progressively increased to approximately twice its baseline level (208+/-30% when Hct levels were less than 10%. In the Oxycyte-treated group on the other hand, rCBF increased by significantly smaller increments, and this group's mean rCBF was only slightly higher than baseline (118+/-18% when Hct levels were less than 10%. Similarly, in the albumin-treated group, rCBF started to increase when hemodilution with albumin caused the CaO(2 to decrease below 17.5 ml/dl. Thereafter, the increase in rCBF was accompanied by a nearly proportional decrease in the CaO(2 level. In the Oxycyte-treated group, the increase in rCBF was significantly smaller than in the albumin-treated group when the CaO(2 level dropped below 10 ml/dl (142+/-20% vs. 186+/-26%, and rCBF returned to almost baseline levels (106+/-15 when the CaO(2 level was below 7 ml/dl. CONCLUSIONS/SIGNIFICANCE: Hemodilution with Oxycyte was accompanied with higher CaO(2 and PO(2 than control group treated with albumin alone. This effect may be partially responsible for maintaining relatively constant CBF and not allowing the elevated blood flow that was observed with albumin.

  12. A simple model of cerebral blood flow dependence on arterial blood pressure

    CERN Document Server

    Gersten, Alexander

    2011-01-01

    It is shown that the dependence of the cerebral blood flow (CBF) on mean arterial blood pressure (MABP) can be described with a simple model having the following assumptions. Below certain MABP (denoted as MABP1) there are no autoregulatory or feedback mechanisms influencing CBF. Between MABP1 and MABP2 (MABP at which breakthrough accurs) there is a linear (on MABP) dependent feedback with a sloap depending very much on the individual considered. The classical autoregulation model with a plateau in between MABP1 and MABP2 is a particular case of this model. The model describes well the experiments performed on dogs (Harper 1966), for which the individual feedback sloap parameter varied to great extent, indicating the importance of mesurments on individuals against averaged mesurments (or measurments on diffent individuals) which superficially support the classical autoregulation. New effect of decreased CBF, while increasing MABP, was observed.

  13. Correlation of Cerebral Blood Flow with Memory in Patients with Cerebral Infarction%脑梗死病人脑血流与记忆的相关研究

    Institute of Scientific and Technical Information of China (English)

    汪洪; 侯靖边; 梁燕; 刘枢晓; 王文富

    2001-01-01

    Objective:To investigate the relation of cerebral blood flow(CBF) and memory in patients with cerebral infarction. Methods:The cerebral blood flow of 30 patients with cerebral infarction and 20 healthy controls was measured. The WMS was used for memory function assessment. Results: CBF and memory performance in patients group were lower than those of controls. There was a statistically significant correlation between CBF and memory performances. Conclusion: The decreasing of CBF was an important causal factor to the memory dysfunction in cerebral infarction patients.

  14. Effect of labetalol on cerebral blood flow and middle cerebral arterial flow velocity in healthy volunteers

    DEFF Research Database (Denmark)

    Schroeder, T; Schierbeck, Jens; Howardy, P;

    1991-01-01

    in normotensive subjects. Neither does it affect CO2 reactivity. The uniform results obtained with the two methods suggest TCD as a usable alternative to conventional CBF technique in the assessment of cerebral vasoactivity of various drugs in subjects with a normal cerebral circulation.......The effect of labetalol, a combined alpha- and beta-adrenoceptor antagonist, on the cerebral circulation was investigated in 7 normotensive subjects. Cerebral blood flow (CBF) was measured with the intravenous 133Xe method and mean flow velocity (Vmean) in the middle cerebral artery was determined...

  15. Role of cerebral blood flow in extreme breath holding

    Directory of Open Access Journals (Sweden)

    Bain Anthony R.

    2016-01-01

    Full Text Available The role of cerebral blood flow (CBF on a maximal breath-hold (BH in ultra-elite divers was examined. Divers (n = 7 performed one control BH, and one BH following oral administration of the non-selective cyclooxygenase inhibitor indomethacin (1.2 mg/kg. Arterial blood gases and CBF were measured prior to (baseline, and at BH termination. Compared to control, indomethacin reduced baseline CBF and cerebral delivery of oxygen (CDO2 by about 26% (p < 0.01. Indomethacin reduced maximal BH time from 339 ± 51 to 319 ± 57 seconds (p = 0.04. In both conditions, the CDO2 remained unchanged from baseline to the termination of apnea. At BH termination, arterial oxygen tension was higher following oral administration of indomethacin compared to control (4.05 ± 0.45 vs. 3.44 ± 0.32 kPa. The absolute increase in CBF from baseline to the termination of apnea was lower with indomethacin (p = 0.01. These findings indicate that the impact of CBF on maximal BH time is likely attributable to its influence on cerebral H+ washout, and therefore central chemoreceptive drive to breathe, rather than to CDO2.

  16. Patterns of fetal lamb regional cerebral blood flow during and after prolonged hypoxia.

    Science.gov (United States)

    Ashwal, S; Majcher, J S; Vain, N; Longo, L D

    1980-10-01

    In an effort to determine to what extent cerebral blood flow (CBF) varies in different parts of the brain during prolonged fetal hypoxia, we measured flow to 34 regions in 12 chronically catheterized fetal lambs 130 to 140 days gestation. Control values of PO2, PCO2 pH, heart rate, and blood pressure were obtained, and CBF was measured by use of radioactive labeled microspheres during a control period, during (15-, 30-, and 90-min) reduction of maternal inspired O2 concentration (fetal arterial PO2 was maintained at 12 to 15 torr), and 60 min after returning the ewe to room air. control blood flow to cortical, subcortical, and brainstem structures equaled 134, 186, and 254 ml x min-1 x 100 g-1, respectively. During hypoxia, CBF increased 92%, and 60 min after fetal oxygenation was restored, it remained 50% above control values. We noted a similar response in regional CBF to the cortex, subcortex, and brainstem during and after hypoxia. Blood flow to smaller areas within the three major regions were quite homogenous and had a similar pattern of response to hypoxia. We conclude that: (1) significant fetal regional CBF differences occurred in utero with brainstem and subcortical flows being substantially greater than flows to other regions of the brain; (2) during prolonged intrauterine hypoxia, total regional CBF increased 92%; (3) 1 hr after fetal oxygenation was restored, CBF still remained 50% above control values; and finally, (4) there was no significant preferential shunting of regional CBF during prolonged hypoxia in utero.

  17. Regulation of cerebral blood flow in mammals during chronic hypoxia: a matter of balance.

    Science.gov (United States)

    Ainslie, Philip N; Ogoh, Shigehiko

    2010-02-01

    Respiratory-induced changes in the partial pressures of arterial carbon dioxide (PaCO2) and oxygen (PaO2) play a major role in cerebral blood flow (CBF) regulation. Elevations in PaCO2 (hypercapnia) lead to vasodilatation and increases in CBF, whereas reductions in PaCO2 (hypocapnia) lead to vasoconstriction and decreases in CBF. A fall in PaO2 (hypoxia) below a certain threshold (balance between the myriad of vasodilators and constrictors derived from the endothelium, neuronal innervations and perfusion pressure. This review examines the extent and mechanisms by which hypoxia regulates CBF. Particular focus will be given to the marked influence of hypoxia associated with exposure to high altitude and chronic lung disease. The associated implications of these hypoxia-induced integrative alterations for the regulation of CBF are discussed, and future avenues for research are proposed.

  18. Heterogeneity of neocortical cerebral blood flow deficits in dementia of the Alzheimer type

    DEFF Research Database (Denmark)

    Waldemar, G; Bruhn, P; Kristensen, M

    1994-01-01

    Regional cerebral blood flow (rCBF) was measured with high resolution brain dedicated single photon emission computer tomography (SPECT) and [99mTc]-d,l-hexamethyl-propylene-amine-oxime (HMPAO) in 25 patients with probable Alzheimer's disease and in 25 control subjects, selected according...... to rigorous inclusion and exclusion criteria. The aim was to analyse the topography of rCBF deficits in individual patients. In the group of patients with Alzheimer's disease as a whole, global CBF was reduced, but a factorial analysis of variance did not show disproportionate reduction of rCBF in any brain...... combination of two, three, or four, of four major brain regions (a left and right frontal and a left and right posterior region). All patients with Alzheimer's disease and none of the control subjects had an abnormal rCBF pattern. Eleven of the 13 different patterns were seen in the patients. Frontal changes...

  19. Cerebral blood flow and brain shrinkage seen on CT during ACTH therapy.

    Science.gov (United States)

    Futagi, Y; Abe, J; Kawahigashi, K

    1986-01-01

    By means of the Doppler ultrasound method, the cerebral blood flow (CBF) was assessed in 21 children with epilepsy undergoing treatment with adrenocorticotrophic hormone (ACTH). The maximum reduction in the internal carotid velocity, as an index of CBF during therapy, was about 35 percent compared with the values before therapy. Furthermore, sequential computed tomography (CT) examinations of the same subjects were performed to evaluate the change in the area of the intracranial brain parenchyma during therapy. The maximum reduction in the parenchymal area during therapy was about 10 percent. This corresponds to a 20 percent reduction in CBF according to Poiseuille's law, however, the remaining reduction in CBF demonstrated by velocity measurement cannot be explained only by that mechanical vascular factor. From these findings, it is concluded that in order to elucidate the mechanism of the CBF reduction, physiological factors such as changes in metabolism during therapy should also be evaluated in addition to the mechanical and physical causes.

  20. Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow

    DEFF Research Database (Denmark)

    Lund, Anton; Secher, Niels H; Hirasawa, Ai;

    2016-01-01

    INTRODUCTION: Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI). METHODS: Seven...... by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (SskinO2) by laser Doppler and white light spectroscopy. RESULTS: During hyperventilation MCAvmean and ICAf decreased...

  1. [Evaluation of regional cortical blood flow by thermal diffusion using a Peltier stack].

    Science.gov (United States)

    Yamagata, S; Kikuchi, H; Hashimoto, K; Minamikawa, J

    1987-08-01

    The possibility of quantitative evaluation of cerebral blood flow (CBF) by thermal diffusion has been reported, when the thermal gradient was created by a Peltier stack. We already described the linear relationship between the CBF and the inverse of thermal gradient elsewhere when the CBF measured by hydrogen clearance (Hydrogen CBF) was compared to the values estimated by thermal diffusion. In this paper, the correlation of linear relationship between the thermal CBF and hydrogen CBF in each animal was first investigated. Secondary, the possibility of in vitro calibration for quantitative evaluation was discussed. Two kinds of probes were manufactured. One was treated not to leak the heat from the Peltier stack except the sensors for the experimental or intraoperative use, and the other was not treated to minimize the size of probe for the long-term use by implantation into the subdural space. When the thermal CBF was compared to hydrogen CBF in each of 3 cats, a linear relationship was obtained in each and the values showing gradient and constant of the regression line were similar in each cat. Moreover, a good linear relationship was also observed when all measurements in 3 cats were included. These results suggested that there is no difference between each animal in the relationship of thermal and hydrogen CBF when the same probe is employed. In addition, the probe can be characterized with two values, and these are gradient and constant of the linear relationship. The fact that the blood flow is proportional to the heat conductivity indicates that the heat conductivity of some material is equivalent to some CBF value in the brain tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Regional cerebral blood flow and blood volume in patients with subcortical arteriosclerotic encephalopathy (SAE).

    Science.gov (United States)

    Gückel, Friedemann J; Brix, Gunnar; Hennerici, Michael; Lucht, Robert; Ueltzhöffer, Christine; Neff, Wolfgang

    2007-10-01

    The aim of the present study was a detailed analysis of the regional cerebral blood flow and blood volume in patients with subcortical arteriosclerotic encephalopathy (SAE) by means of functional magnetic resonance imaging (MRI). A group of 26 patients with SAE and a group of 16 age-matched healthy volunteers were examined. Using a well-established dynamic susceptibility contrast-enhanced MRI method, the regional cerebral blood flow (rCBF) and blood volume (rCBV) were quantified for each subject in 12 different regions in the brain parenchyma. As compared to healthy volunteers, patients with SAE showed significantly reduced rCBF and rCBV values in white matter regions and in the occipital cortex. Regions containing predominantly grey matter show almost normal rCBF and rCBV values. In conclusion, quantitative analysis of rCBF and rCBV values demonstrates clearly that SAE is a disease that is associated with a reduced microcirculation predominantly in white matter.

  3. Intensive blood pressure lowering increases cerebral blood flow in older subjects with hypertension.

    Science.gov (United States)

    Tryambake, Dinesh; He, Jiabao; Firbank, Michael J; O'Brien, John T; Blamire, Andrew M; Ford, Gary A

    2013-06-01

    Hypertension is associated with reduced cerebral blood flow (CBF). Intensive (blood pressure (BP) lowering in older people might give greater reduction in cardiovascular risk, but there are concerns that this might produce hypoperfusion which may precipitate falls and possibly stroke. We determined the effect of intensive compared with usual BP lowering on CBF in hypertensive older subjects. Individuals aged >70 years with a history of systolic hypertension on 1 or no BP lowering drugs were recruited from primary care (n=37; age, 75±4 years; systolic BP, >150 mm Hg) and randomized to receive intensive (target BP, treatment. Baseline BP (ambulatory or in clinic) and baseline gray matter CBF were not significantly different between the groups. After treatment, BP was reduced significantly in both groups but fell more in the intensive group (26/17 versus 15/5 mm Hg; Phypertension increases CBF, compared with BP lowering to usual target. These findings suggest hypertension in older people shifts the autoregulatory CBF curve rightward and downward and is reversible with BP lowering.

  4. Blood flow activation in rat somatosensory cortex under sciatic nerve stimulation revealed by laser speckle imaging

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In many functional neuroimaging research the change of local cerebral blood flow (CBF) induced by sensory stimulation is regarded as an indicator of the change in cortical neuronal activity although a precise and full spatio-temporal description of local CBF response coupled to neural activity has still not been laid out. Using the laser speckle imaging technique a relatively large exposed area in somatosensory cortex of rat was imaged for the observation of the variations of CBF during sciatic nerve stimulation. The results showed that cerebral blood flow activation was spatially localized and discretely distributed in the targeted microvasculature. Individual arteries, veins and capillaries in different diameters were activated with the time going. The response pattern of CBF related to the function of brain activity and energy metabolism is delineated exactly.

  5. Cerebral blood flow regulation, exercise and pregnancy: why should we care?

    Science.gov (United States)

    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.

  6. The Cerebral Blood Flow Biomedical Informatics Research Network (CBFBIRN) Data Repository

    Science.gov (United States)

    Shin, David D.; Ozyurt, I. Burak; Brown, Gregory G.; Fennema-Notestine, Christine; Liu, Thomas T.

    2015-01-01

    Arterial spin labeling (ASL) MRI provides an accurate and reliable measure of cerebral blood flow (CBF). A rapidly growing number of CBF measures are being collected both in clinical and research settings around the world, resulting in a large volume of data across a wide spectrum of study populations and health conditions. Here, we describe a central CBF data repository with integrated processing workflows, referred to as the Cerebral Blood Flow Biomedical Informatics Research Network (CBFBIRN). The CBFBIRN provides an integrated framework for the analysis and comparison of CBF measures across studies and sites. In this work, we introduce the main capabilities of the CBFBIRN (data storage, processing and sharing), describe what types of data are available, explain how users can contribute to the data repository and access existing data from it, and discuss our long term plans for the CBFBIRN. PMID:26032887

  7. Dehydration affects cerebral blood flow but not its metabolic rate for oxygen during maximal exercise in trained humans

    DEFF Research Database (Denmark)

    Trangmar, Steven J; Chiesa, Scott T; Stock, Christopher G

    2014-01-01

    venous noradrenaline, and falling arterial carbon dioxide tension (P aCO 2) (R(2) ≥ 0.41, P ≤ 0.01) whereas CCA flow and conductance were related to elevated blood temperature. In conclusion, dehydration accelerated the decline in CBF by decreasing P aCO 2 and enhancing vasoconstrictor activity. However......Intense exercise is associated with a reduction in cerebral blood flow (CBF), but regulation of CBF during strenuous exercise in the heat with dehydration is unclear. We assessed internal (ICA) and common carotid artery (CCA) haemodynamics (indicative of CBF and extra-cranial blood flow), middle...... cerebral artery velocity (MCA Vmean), arterial-venous differences and blood temperature in 10 trained males during incremental cycling to exhaustion in the heat (35°C) in control, dehydrated and rehydrated states. Dehydration reduced body mass (75.8 ± 3 vs. 78.2 ± 3 kg), increased internal temperature (38...

  8. Regional cerebral blood flow abnormalities in patients with primary hyperparathyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Cermik, Tevfik F. [Hospital of the University of Trakya, Department of Nuclear Medicine, Edirne (Turkey); Trakya Universitesi Hastanesi, Nukleer Tip Anabilim Dali, Gullapoglu Yerleskesi, Edirne (Turkey); Kaya, Meryem; Bedel, Deniz; Berkarda, Sakir; Yigitbasi, Oemer N. [Hospital of the University of Trakya, Department of Nuclear Medicine, Edirne (Turkey); Ugur-Altun, Betuel [Hospital of the University of Trakya, Department of Internal Medicine, Division of Endocrinology, Edirne (Turkey)

    2007-04-15

    We assessed the alterations in regional cerebral blood flow (rCBF) in patients with primary hyperparathyroidism (PHP) before parathyroidectomy by semiquantitative analysis of brain single photon emission computed tomography (SPECT) images. Included in this prospective study were 14 patients (mean age 47.6 {+-} 10.4 years; 3 male, 11 female) and 10 control subjects (mean age 36.0 {+-} 8.5 years, 6 male, 4 female) were SPECT imaging was performed using a dual-headed gamma camera 60-90 min after intravenous administration of 925 MBq Tc-99m HMPAO. The corticocerebellar rCBF ratios were calculated from 52 brain areas and reference lower values (RLVs) were calculated from the rCBF ratios of control subjects. The regional ratios that were below the corresponding RLV were considered abnormal (hypoperfused). Hypoperfusion was shown in 171 out of 728 regions (23%) and there was a significant correlation between serum calcium, PTH levels and the sum of hypoperfused regions in the patient group (R = 0.75 and P = 0.001, and R = 0.75, P = 0.001, respectively). Significantly reduced rCBF were found in the following cortical regions: bilateral cingulate cortex, superior and inferior frontal cortex, anterior temporal cortex, precentral gyrus, postcentral gyrus and parietal cortex, and right posterior temporal cortex. Our results indicate that alterations in rCBF in patients with PHP can be demonstrated with brain SPECT. The correlation between serum calcium, PTH levels and the sum of hypoperfused regions indicates that there may be a strong relationship between rCBF abnormalities and increased levels of serum calcium and PTH. In addition, the degree of rCBF abnormalities could be determined by brain SPECT in PHP patients with or without psychiatric symptoms. (orig.)

  9. Effects of axillary blockade on regional cerebral blood flow during dynamic hand contractions

    DEFF Research Database (Denmark)

    Friedman, D B; Friberg, L; Payne, G;

    1992-01-01

    Regional cerebral blood flow (rCBF) was measured at orbitomeatal (OM) plane +5.0 and +9.0 cm in 10 subjects at rest and during dynamic hand contractions before and after axillary blockade. Handgrip strength was significantly reduced, and rating of perceived exertion increased after blockade. During...... hand contractions before blockade, contralateral hemispheric cerebral blood flow (CBF) at OM +9.0 increased from a resting value of 58 (49-75) to 63 (52-82) ml.100 g-1.min-1; contralateral motor sensory rCBF at OM +9 from 58 (50-77) to 71 (64-84); motor sensory rCBF at OM +5 from 67 (54-76) to 77 (64......-87) and 70 (62-84) contralaterally and ipsilaterally, respectively; and supplementary motor area (SM) rCBF from 64 (53-69) to 75 (67-88) ml.100 g-1.min-1. During dynamic hand contractions after axillary blockade, CBF did not increase at OM +5 or in the SM. Furthermore, contralateral motor sensory rCBF at OM...

  10. A study on measurement of the regional cerebral blood flow using autoradiographic method in moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Tomohiro; Kiya, Katsuzo; Yuki, Kiyoshi; Kawamoto, Hitoshi; Mizoue, Tatsuya; Kiura, Yoshihiro; Uozumi, Tohru [Hiroshima Prefectural Hospital (Japan); Ikawa, Fusao

    1997-11-01

    Development of Autoradiographic method (ARG) has provided measurement of cerebral blood flow in moyamoya disease. We evaluate a cerebral vasodilatory capacity (CVC) for moyamoya disease using ARG method. We used 5 patients with moyamoya disease as a candidate for measurement of the cerebral blood flow (CBF) who admitted to Hiroshima Prefectural Hospital during the past one year. There were 3 patients in an adult age and 2 patients in a young age. We tried to measure the regional CBF (rCBF) using ARG method which was a easy way to estimate the rCBF on SPECT. The CVC was calculated from the difference of the rCBF between resting SPECT and Diamox-loading SPECT. Results were as follows; Reactivity of cerebral vessels to CO{sub 2} loading and CVC weakened in moyamoya disease. The rCBF and CVC in the territories of anterior and middle cerebral arteries reduced in comparison with those in the area supplied by the posterior cerebral artery. The CVC at the treated side with surgical reconstruction recovered somewhat in an adult type. From these results, measurement of CBF using ARG method seems to be useful for evaluation of the CVC in moyamoya disease. (author)

  11. Changes in cerebral blood flow after acetazolamide: an experimental study comparing near-infrared spectroscopy and SPECT

    DEFF Research Database (Denmark)

    Schytz, H W; Wienecke, Troels; Jensen, Lars Thorbjørn;

    2009-01-01

    BACKGROUND AND PURPOSE: It is important to find a reliable and bedside method, which can estimate the cerebral blood flow (CBF) of patients in clinical settings. Estimation of CBF by calculating a blood flow index (BFI) using continuous wave near-infrared spectroscopy (CW-NIRS) and indocyanine...... green (ICG) as an i.v. tracer has been proposed to be a feasible and promising method. To validate if the BFI method can detect relative changes in CBF we compared data with the established method (133)Xenon single photon emission computer tomography ((133)Xe-SPECT). METHODS: Ten healthy subjects were...

  12. Focal increase of cerebral blood flow during stereognostic testing in man

    DEFF Research Database (Denmark)

    Roland, E; Larsen, B

    1976-01-01

    An attempt was made to study the regional cerebral blood flow (rCBF) pattern during stereognostic discrimination in man. The rCBF was measured in 18 subjects who had no major neurological defects. The clearance from the hemisphere of xenon 133 injected (133Xe) into the carotid artery was measured...... with a 254-channel dynamic gamma camera. During stereognostic discrimination with hand, mouth, or foot, the rCBF increased focally in the corresponding contralateral sensory-motor region and increased focally in the premotor part of the frontal lobe. The increase in the sensory region was attributed...

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

    Science.gov (United States)

    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.

  14. Dependency of cerebral blood flow upon mean arterial pressure in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten; Larsen, Fin Stolze; Qvist, Jesper;

    2000-01-01

    OBJECTIVE: Patients with acute bacterial meningitis are often treated with sympathomimetics to maintain an adequate mean arterial pressure (MAP). We studied the influence of such therapy on cerebral blood flow (CBF). DESIGN: Prospective physiologic trial. SETTING: The Department of Infectious...... Diseases, Copenhagen University Hospital, Denmark. PATIENTS: Sixteen adult patients with acute bacterial meningitis. INTERVENTION: Infusion of norepinephrine to increase MAP. MEASUREMENTS: During a rise in MAP induced by norepinephrine infusion, we measured relative changes in CBF by transcranial Doppler...... bacterial meningitis, CBF autoregulation is impaired. With recovery from meningitis, the cerebral vasculature regains the ability to maintain cerebral perfusion at a constant level despite variations in MAP....

  15. Regional cerebral blood flow alterations remote from the site of intracranial tumors

    DEFF Research Database (Denmark)

    Endo, H; Larsen, B; Lassen, N A

    1977-01-01

    Regional cerebral blood flow (rCBF) was investigated in 12 patients with brain tumors, using a 254-channel dynamic gamma camera. In nine of the 12 cases, hyperemic regions with loss of autoregulation were seen in sites remote from the tumor (the area around the tumor was in most cases also...... hyperemic). These remote rCBF abnormalities were found in the lower posterior part of the hemisphere in six cases, and in the frontal region in three. The location of the remote rCBF abnormality seemed to depend on the site of the tumor: cases with frontal and posterior fossa mass lesions had hyperemia...

  16. Sympathetic influence on cerebral blood flow and metabolism during exercise in humans

    DEFF Research Database (Denmark)

    Seifert, Thomas; Secher, Niels H

    2011-01-01

    This review focuses on the possibility that autonomic activity influences cerebral blood flow (CBF) and metabolism during exercise in humans. Apart from cerebral autoregulation, the arterial carbon dioxide tension, and neuronal activation, it may be that the autonomic nervous system influences CBF......, but increases during cycling exercise. The increase in CMRO(2) is unaffected by beta-adrenergic blockade even though CBF is reduced suggesting that cerebral oxygenation becomes critical and a limited cerebral mitochondrial oxygen tension may induce fatigue. Also, sympathetic activity may drive cerebral non...

  17. Color functional images of the cerebral blood flow. [/sup 133/Xe

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, H.; Iio, M.; Iisaka, J.; Chiba, K.; Yamada, H.; Matsui, K.; Hoshi, Y.; Fuse, M.

    1976-11-01

    Functional gamma imaging, in color, was established for regional cerebral blood flow (rCBF) using /sup 133/Xe. During 10 min after intracarotid injection of /sup 133/Xe in saline, 60 picture frames of the /sup 133/Xe clearance curve for the entire hemisphere were obtained. After nine-point smoothing, the rCBF for each of the 4,096 picture elements was calculated by two methods: the half-time method and the height-over-area method. Both the /sup 133/Xe clearance half-times and the calculated CBF values were displayed, using 13 steps of color, as functional CBF images of the brain. Images of peak count and total count were also displayed on the same frame of the color television. Forty-six studies, performed on 37 patients with various cerebral disorders, were divided into two types: diffuse and focal. In the diffuse type, a decrease in CBF was noted in cases of normal-pressure hydrocephalus; successful ventriculoperitoneal shunt operations were followed by recovery of CBF. Occlusion of the middle cerebral artery showed up as a wedge-shaped area of decreased CBF, even when the conventional brain scan looked normal. Increased perfusion to a tumor was frequently associated with decreased CBF in the rest of the lateral hemisphere; such a decrease could be improved by surgical removal of the tumor.

  18. Relationships between Cerebral Blood Flow and IQ in Typically Developing Children and Adolescents.

    Science.gov (United States)

    Kilroy, Emily; Liu, Collin Y; Yan, Lirong; Kim, Yoon Chun; Dapretto, Mirella; Mendez, Mario F; Wang, Danny J J

    2011-01-01

    The objective of this study was to explore the relationships between IQ and cerebral blood flow (CBF) measured by arterial spin labeling (ASL) in children and adolescents. ASL was used to collect perfusion MRI data on 39 healthy participants aged 7 to 17. The Wechsler Abbreviated Intelligence Scale was administered to determine IQ scores. Multivariate regression was applied to reveal correlations between CBF and IQ scores, accounting for age, sex and global mean CBF. Voxel Based Morphometry (VBM) analysis, which measures regional cortical volume, was performed as a control. Regression analyses were further performed on CBF data with adjustment of regional gray matter density (GMD). A positive correlation between CBF and IQ scores was primarily seen in the subgenual/anterior cingulate, right orbitofrontal, superior temporal and right inferior parietal regions. An inverse relationship between CBF and IQ was mainly observed in bilateral posterior temporal regions. After adjusting for regional GMD, the correlations between CBF and IQ in the subgenual/anterior cingulate cortex, right orbitofrontal, superior temporal regions and left insula remained significant. These findings support the Parieto-Frontal Integration Theory of intelligence, especially the role of the subgenual/anterior cingulate cortex in the neural networks associated with intelligence. The present study also demonstrates the unique value of CBF in assessing brain-behavior relationships, in addition to structural morphometric measures.

  19. Cerebral blood flow in sickle cell cerebrovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Attempts to Improve Absolute Quantification of Cerebral Blood Flow in Dynamic Susceptibility Contrast Magnetic Resonance Imaging: A Simplified T1-Weighted Steady-State Cerebral Blood Volume Approach

    Energy Technology Data Exchange (ETDEWEB)

    Wirestam, R.; Knutsson, L.; Risberg, J.; Boerjesson, S.; Larsson, E.M.; Gustafson, L.; Passant, U.; Staahlberg, F. [Depts. of Medical Radiation Physics, Diagnostic Radiology, Psychiatry, and Psychogeriatrics, Lund Univ, Lund (Sweden)

    2007-07-15

    Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations. Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate. Material and Methods: 17 volunteers were investigated by DSC-MRI and 133Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = KxCBF(DSC). Results: Average whole-brain SPECT CBF was 40.1{+-}6.9 ml/min 100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2{+-}13.8 ml/mi 100 g. After correction with the calibration factor, a CBF(ss) of 42.7{+-}14.0 ml/min 100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52). Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference 133Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.

  1. Age-related differences in cerebral blood flow underlie the BOLD FMRI signal in childhood

    Directory of Open Access Journals (Sweden)

    Pamela eMoses

    2014-04-01

    Full Text Available Functional magnetic resonance imaging (FMRI has become a premiere technique for studying the development and neural mediation of a wide range of typical and atypical behaviors in children. While the mechanism of the blood oxygen level-dependent (BOLD FMRI signal has been a focus of investigation in the mature brain, it has been largely unexamined in the developing brain. One critical component of the BOLD signal that has been noted to change with age is cerebral blood flow (CBF. Reports of CBF in children based on clinical radioactive tracing methods have found elevated CBF in childhood relative to adulthood, which could affect the BOLD response. This study used noninvasive arterial spin labeling (ASL MRI to study resting state and activity-driven CBF in conjunction with the functional BOLD response in healthy children 8 and 12 years of age and in adults. Participants performed a finger tapping task to generate robust activation measured in the motor cortex. Quantification of resting state CBF demonstrated higher CBF in 8 year olds and in 12 year olds relative to adults. The absolute increase in CBF between baseline rest and peak response during the motor task was also higher in children compared to adults. In contrast, the relative increase of CBF above baseline, expressed as percent of CBF change, was comparable across groups. The percent of BOLD signal change was also stable across age groups. This set of findings suggest that along with elevated CBF in childhood, other component processes of the BOLD response are also in an elevated state such that together they yield a net BOLD effect that resembles adults. These findings are consistent with our previous examination hemodynamics in primary sensory cortex. Although the magnitude of the BOLD response appears consistent between childhood and adulthood, the underlying physiology and cerebrovascular dynamics that give rise to the BOLD effect differ between immature and mature brains neural

  2. The reproducibility of cerebral blood flow with N-isopropyl-p-({sup 123}I) iodoamphetamine by arterial blood sampling method

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kazufumi; Tamura, Kiyohiko [Akita Univ. (Japan). Hospital; Hirano, Hiroko; Oyama, Yoichi; Kobayashi, Mitsuru; Tomura, Noriaki; Watari, Jiro

    1997-12-01

    The reproducibility of cerebral blood flow (CBF) based on the microsphere model with N-isopropyl-p-({sup 123}I) iodoamphetamine (IMP), was evaluated 4.58% (=CV) and was within 9%. The former was calculated from the elementary experiments, the latter was calculated with the CBF of 11 cases. On the clinical conditions, where we selected some astrocytomas of grade III injected ACNU super selectively with Seldinger catheter, and quantified CBF both pre and post ACNU ia by the ROI of 16.2 mm{phi}. On the other hand we have been monitoring the Cross Calibration Factors (CCFs) since we started CBF quantification. The CCFs during 5 years were all within the upper and the lower control limits. At a worst case the average deviation of CCF was 1.17% by a month, which is equal to 7.0% by 6 months. Then SPECT and well counter should be calibrated at least once every 6 months. (author)

  3. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    DEFF Research Database (Denmark)

    Thomsen, H; Steffensen, E; Larsson, Elna-Marie

    2012-01-01

    technique arterial spin labelling (ASL) presently provides measurement only of cerebral blood flow (CBF), which has not been widely used in human brain tumor studies. Purpose: To assess if measurement of blood flow is comparable with measurement of blood volume in human biopsy-proven gliomas obtained by DSC......, and glioblastomas. Results: rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r ¼ 0.60) and to the cerebellum (r ¼ 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated......-MRI using two different regions for normalization and two different measurement approaches. Material and Methods: Retrospective study of 61 patients with different types of gliomas examined with DSC perfusion MRI. Regions of interest (ROIs) were placed in tumor portions with maximum perfusion on rCBF and r...

  4. Clinical application of /sup 99m/Tc-HM-PAO for cerebral blood flow imaging by SPECT. Comparison with cerebral blood flow study by PET

    Energy Technology Data Exchange (ETDEWEB)

    Inugami, Atsushi; Uemura, Kazuo; Shishido, Fumio; Tomura, Noriaki; Higano, Shuichi; Fujita, Hideaki; Kanno, Iwao

    1988-02-01

    Recently, a new tracer for cerebral blood flow (CBF) study; /sup 99m/Tc-labelled-hexamethyl-propyleneamine-oxime (/sup 99m/Tc-HM-PAO) was developed by Amersham international institute. In this paper, we reported the initial experience of tomographic CBF imaging with /sup 99m/Tc-HM-PAO in the comparison of CBF study using positron CT (PET) and 0 approx. 15 labelled CO/sub 2/. Thirty-nine patients with cerebro-vascular disease were examined mainly in the acute phase. All the subjects showed verious disturbances of CBF, which corresponded well to the PET study. However, the image-contrast with /sup 99m/Tc-HM-PAO were inferior to those of the PET study. /sup 99m/Tc-HM-PAO is considered to a good radiopharmaceutical which is readily applicable to eaven an emergency cases.

  5. A comparison of measurements of cerebral blood flow in the rabbit using laser Doppler spectroscopy and radionuclide labelled microspheres.

    Science.gov (United States)

    Eyre, J A; Essex, T J; Flecknell, P A; Bartholomew, P H; Sinclair, J I

    1988-02-01

    Laser Doppler spectroscopy has been evaluated for the measurement of cerebral blood flow (CBF) by correlation with simultaneous measurements by radionuclide labelled microspheres. The experimental procedures were carried out on five anaesthetised rabbits. The cortical tissue was exposed by means of a small burr hole and illuminated by a helium neon laser (632.8 nm). Reflected light was detected using a silicon photodiode, and CBF was calculated continuously from the power of the frequency weighted Doppler spectrum in the reflected light. Three successive measurements of CBF were made using the microsphere technique. Following an initial baseline measurement, CBF was increased by an infusion of metaraminol and then reduced by controlled haemorrhage. Laser Doppler spectroscopy provided continuous monitoring of blood flow fluctuations and during the haemorrhage it was possible to demonstrate CBF autoregulation until the mean blood pressure fell below 6.7 kPa (50 mmHg). A regression analysis was performed between the simultaneous CBF measurements from the two techniques using a least squares best fit straight line analysis (r = 0.92, P less than 0.001). It was concluded that the flow computed from laser Doppler spectroscopy varied linearly with CBF and offers the unique advantage of continuous and instantaneous measurements even during nonsteady state flow.

  6. Effects of histamine and related compounds on regional cerebral blood flow in rats.

    Science.gov (United States)

    Suzuki, G; Chen, Z; Sugimoto, Y; Fujii, Y; Kamei, C

    1999-11-01

    The effects of histamine and related compounds on regional cerebral blood flow (rCBF) in the hippocampus of conscious rats were studied. Intracerebroventricular injection of histamine caused a dose-dependent increase in rCBF in the hippocampus, and similar findings were observed with not only the H1 agonist, 2-thiazolylethylamine, but also the H2 agonist, dimaprit. Intraperitoneal injection of L-histidine also resulted in an increase in rCBF in the hippocampus, in parallel with elevation of histamine content in the brain. The increase in rCBF in the hippocampus induced by L-histidine was antagonized by both H1 and H2 antagonists (diphenhydramine, pyrilamine and zolantidine). In addition, when both antagonists were injected simultaneously, an additive effect was observed in antagonism of the L-histidine-induced increase in rCBF. L-Histidine caused no marked changes in blood pressure even at a dose of 1,500 mg/kg, which showed an increase in rCBF in the hippocampus. These results indicate that histamine elicited an increase in rCBF via both H1 and H2 receptors.

  7. Evaluation of the Extension of the Cerebral Blood Flow and its Main Parameters

    CERN Document Server

    Gersten, A

    1999-01-01

    Among the major factors controlling the cerebral blood flow (CBF) - cerebral perfusion pressure, arterial partial pressure of oxygen (PaO2), cerebral metabolism, arterial partial pressure of carbon dioxide (PaCO2), and cardiac output, the effect of PaCO2 is peculiar in being independent of autoregulatory CBF mechanisms and it allows to explore the full range of the CBF. We have developed a simple physical model, and have derived a simple four parameter formula, relating the CBF to PaCO2. The parameters can be extracted in an easy way, directly from the experimental data. With this model five experimental data sets of human, rats, baboons and dogs were well fitted. The same type of parametrization was also used successfully for fitting experimental data of PaO2 of dogs. We have also looked on the dependence of the parameters on other factors and were able to evaluate their dependence on the mean arterial blood pressure.

  8. Quantification of cerebral blood flow by flow-sensitive alternating inversion recovery exempting separate T1 measurement in healthy volunteers

    Institute of Scientific and Technical Information of China (English)

    XIAO Jiang-xi; ZHANG Xue-hui; XIE Sheng; ZOU Run-lei

    2006-01-01

    Background The feasibility of the mapping of quantitative cerebral blood flow (CBF) named flow-sensitive alternating inversion recovery exempting separate T1 measurement (FAIREST) is still controversial. This study aimed to evaluate the reliability of FAIREST in the measurement of regional CBF (rCBF) in healthy volunteers.Methods Eighteen healthy volunteers underwent magnetic resonance (MR) scanning with the sequence of FAIREST. While they were at rest, rCBF values were obtained in various brain regions of interest (ROIs). The same scheme was repeated on every subject after two weeks. Statistical analysis was made to determine the effect of location, scan and side on the measurement of rCBF.Results The mean CBF values were (122 ± 28) ml · (100 g)-1 · min-1 and (43 ±10) ml · (100 g)-1 · min-1 in the gray and white matter respectively. There was significant main effect of location (t=-12.5, P<0.01), but no significant effect of side. Paired t-test of ROIs in the same slice showed no significant difference in most sites between two scans, except in the gray matter of the bilateral frontal lobes (t=2.18-2.34, P <0.05). However, the rCBF values of the same structure obtained from different slices showed a significant difference (t=-3.49,P<0.01).Conclusion FAIREST is a reliable technique in the measurement of rCBF, but different imaging slice may affect the agreement of rCBF across the scans.

  9. Metabolic control of resting hemispheric cerebral blood flow is oxidative, not glycolytic.

    Science.gov (United States)

    Powers, William J; Videen, Tom O; Markham, Joanne; Walter, Vonn; Perlmutter, Joel S

    2011-05-01

    Although the close regional coupling of resting cerebral blood flow (CBF) with both cerebral metabolic rate of oxygen (CMRO(2)) and cerebral metabolic rate of glucose (CMRglc) within individuals is well documented, there are few data regarding the coupling between whole brain flow and metabolism among different subjects. To investigate the metabolic control of resting whole brain CBF, we performed multivariate analysis of hemispheric CMRO(2), CMRglc, and other covariates as predictors of resting CBF among 23 normal humans. The univariate analysis showed that only CMRO(2) was a significant predictor of CBF. The final multivariate model contained two additional terms in addition to CMRO(2): arterial oxygen content and oxygen extraction fraction. Notably, arterial plasma glucose concentration and CMRglc were not included in the final model. Our data demonstrate that the metabolic factor controlling hemispheric CBF in the normal resting brain is CMRO(2) and that CMRglc does not make a contribution. Our findings provide evidence for compartmentalization of brain metabolism into a basal component in which CBF is coupled to oxygen metabolism and an activation component in which CBF is controlled by another mechanism.

  10. Cerebral Blood Flow and Transcranial Doppler Sonography Measurements of CO(2)-Reactivity in Acute Traumatic Brain Injured Patients

    DEFF Research Database (Denmark)

    Reinstrup, Peter; Ryding, Erik Hilmer; Asgeirsson, Bogi;

    2013-01-01

    BACKGROUND: Cerebral blood flow (CBF) measurements are helpful in managing patients with traumatic brain injury (TBI), and testing the cerebrovascular reactivity to CO(2) provides information about injury severity and outcome. The complexity and potential hazard of performing CBF measurements...... limits routine clinical use. An alternative approach is to measure the CBF velocity using bedside, non-invasive, and transcranial Doppler (TCD) sonography. This study was performed to investigate if TCD is a useful alternative to CBF in patients with severe TBI. METHOD: CBF and TCD flow velocity...... measurements and cerebrovascular reactivity to hypocapnia were simultaneously evaluated in 27 patients with acute TBI. Measurements were performed preoperatively during controlled normocapnia and hypocapnia in patients scheduled for hematoma evacuation under general anesthesia. MAIN FINDING AND CONCLUSION...

  11. Quantitative measurement of cerebral blood flow in a juvenile porcine model by depth-resolved near-infrared spectroscopy

    Science.gov (United States)

    Elliott, Jonathan T.; Diop, Mamadou; Tichauer, Kenneth M.; Lee, Ting-Yim; Lawrence, Keith St.

    2010-05-01

    Nearly half a million children and young adults are affected by traumatic brain injury each year in the United States. Although adequate cerebral blood flow (CBF) is essential to recovery, complications that disrupt blood flow to the brain and exacerbate neurological injury often go undetected because no adequate bedside measure of CBF exists. In this study we validate a depth-resolved, near-infrared spectroscopy (NIRS) technique that provides quantitative CBF measurement despite significant signal contamination from skull and scalp tissue. The respiration rates of eight anesthetized pigs (weight: 16.2+/-0.5 kg, age: 1 to 2 months old) are modulated to achieve a range of CBF levels. Concomitant CBF measurements are performed with NIRS and CT perfusion. A significant correlation between CBF measurements from the two techniques is demonstrated (r2=0.714, slope=0.92, p<0.001), and the bias between the two techniques is -2.83 mL.min-1.100 g-1 (CI0.95: -19.63 mL.min-1.100 g-1-13.9 mL.min-1.100 g-1). This study demonstrates that accurate measurements of CBF can be achieved with depth-resolved NIRS despite significant signal contamination from scalp and skull. The ability to measure CBF at the bedside provides a means of detecting, and thereby preventing, secondary ischemia during neurointensive care.

  12. Effect of pregnancy and nitric oxide on the myogenic vasodilation of posterior cerebral arteries and the lower limit of cerebral blood flow autoregulation.

    Science.gov (United States)

    Chapman, Abbie C; Cipolla, Marilyn J; Chan, Siu-Lung

    2013-09-01

    Hemorrhage during parturition can lower blood pressure beyond the lower limit of cerebral blood flow (CBF) autoregulation that can cause ischemic brain injury. However, the impact of pregnancy on the lower limit of CBF autoregulation is unknown. We measured myogenic vasodilation, a major contributor of CBF autoregulation, in isolated posterior cerebral arteries (PCAs) from nonpregnant and late-pregnant rats (n = 10/group) while the effect of pregnancy on the lower limit of CBF autoregulation was studied in the posterior cerebral cortex during controlled hemorrhage (n = 8). Pregnancy enhanced myogenic vasodilation in PCA and shifted the lower limit of CBF autoregulation to lower pressures. Inhibition of nitric oxide synthase (NOS) prevented the enhanced myogenic vasodilation during pregnancy but did not affect the lower limit of CBF autoregulation. The shift in the autoregulatory curve to lower pressures during pregnancy is likely protective of ischemic injury during hemorrhage and appears to be independent of NOS.

  13. Nitric oxide (NO) is an endogenous anticonvulsant but not a mediator of the increase in cerebral blood flow accompanying bicuculline-induced seizures in rats

    DEFF Research Database (Denmark)

    Wang, Qian; Theard, M A; Pelligrino, D A;

    1994-01-01

    ) is NO an endogenous anticonvulsant or proconvulsant substance? and (2) is the cerebral blood flow (CBF) increase accompanying bicuculline (BC)-induced seizures mediated by NO? The experiments were performed in 300-400-g Wistar rats anesthetized with 0.6% halothane and 70% N2O/30% O2. CBF was measured using...

  14. Comparison of the effects of NG-nitro-L-arginine and indomethacin on the hypercapnic cerebral blood flow increase in rats

    DEFF Research Database (Denmark)

    Wang, Qian; Pelligrino, D A; Paulson, O B;

    1994-01-01

    The effects of NG-nitro-L-arginine (NOLAG), an inhibitor of nitric oxide synthase (NOS), and of indomethacin, an inhibitor of cyclooxygenase, on the rise in cerebral blood flow (CBF) accompanying increasing levels of hypercapnia (paCO2 = 40-135 mmHg) were studied in anesthetized rats. CBF...

  15. Carbon dioxide induced changes in cerebral blood flow and flow velocity: role of cerebrovascular resistance and effective cerebral perfusion pressure.

    Science.gov (United States)

    Grüne, Frank; Kazmaier, Stephan; Stolker, Robert J; Visser, Gerhard H; Weyland, Andreas

    2015-09-01

    In addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2-induced changes in CBF, CVR, CPPe, ZFP, and RAP is not fully understood. In a controlled crossover trial, we investigated 10 anesthetized patients aiming at PaCO2 levels of 30, 37, 43, and 50 mm Hg. Cerebral blood flow was measured with a modified Kety-Schmidt-technique. Zero flow pressure and RAP was estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. Effective cerebral perfusion pressure was calculated as the difference between mean arterial pressure and ZFP, CVR as the ratio CPPe/CBF. Statistical analysis was performed by one-way RM-ANOVA. When comparing hypocapnia with hypercapnia, CBF showed a significant exponential reduction by 55% and mean VMCA by 41%. Effective cerebral perfusion pressure linearly decreased by 17% while ZFP increased from 14 to 29 mm Hg. Cerebrovascular resistance increased by 96% and RAP by 39%; despite these concordant changes in mean CVR and Doppler-derived RAP correlation between these variables was weak (r=0.43). In conclusion, under general anesthesia hypocapnia-induced reduction in CBF is caused by both an increase in CVR and a decrease in CPPe, as a consequence of an increase in ZFP.

  16. Distributed Cerebral Blood Flow estimation using a spatiotemporal hemodynamic response model and a Kalman-like Filter approach

    KAUST Repository

    Belkhatir, Zehor

    2015-11-23

    This paper discusses the estimation of distributed Cerebral Blood Flow (CBF) using spatiotemporal traveling wave model. We consider a damped wave partial differential equation that describes a physiological relationship between the blood mass density and the CBF. The spatiotemporal model is reduced to a finite dimensional system using a cubic b-spline continuous Galerkin method. A Kalman Filter with Unknown Inputs without Direct Feedthrough (KF-UI-WDF) is applied on the obtained reduced differential model to estimate the source term which is the CBF scaled by a factor. Numerical results showing the performances of the adopted estimator are provided.

  17. Effect of short-term hyperventilation on cerebral blood flow autoregulation in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten

    2000-01-01

    BACKGROUND AND PURPOSE: Cerebral blood flow (CBF) autoregulation is impaired in patients with acute bacterial meningitis: this may be caused by cerebral arteriolar dilatation. We tested the hypothesis that CBF autoregulation is recovered by acute mechanical hyperventilation in 9 adult patients...... with acute bacterial meningitis. METHODS: Norepinephrine was infused to increase mean arterial pressure (MAP) 30 mm Hg from baseline. Relative changes in CBF were concomitantly recorded by transcranial Doppler ultrasonography of the middle cerebral artery, measuring mean flow velocity (V...... completely during hyperventilation. The slope of the autoregulation curve decreased during hyperventilation compared with normoventilation (Pmeningitis, indicating...

  18. Potential language and attentional networks revealed through factor analysis of rCBF data measured with SPECT

    DEFF Research Database (Denmark)

    McLaughlin, T; Steinberg, B; Christensen, B

    1992-01-01

    We used changes in regional cerebral blood flow (rCBF) to disclose regions involved in central auditory and language processing in the normal brain. rCBF was quantified with a fast-rotating, single-photon emission computerized tomograph (SPECT) and inhalation of 133Xe. rCBF data were obtained......'s area (left hemisphere), when subjects listened to narrative speech, compared to white noise (baseline). No significant rCBF differences were detected with this test during dichotic stimulation vs. white noise. A more sophisticated statistical method (factor analysis) disclosed patterns of functionally...... intercorrelated regions. The factor analysis reduced the highly intercorrelated rCBF measures from 28 regions of interest to a set of three independent factors. These factors accounted for 77% of the total variation in rCBF values. These three factors appeared to represent statistical analogues of independent...

  19. Alpha-contingent EEG feedback reduces SPECT rCBF variability

    DEFF Research Database (Denmark)

    McLaughlin, Thomas; Steinberg, Bruce; Mulholland, Thomas

    2005-01-01

    EEG feedback methods, which link the occurrence of alpha to the presentation of repeated visual stimuli, reduce the relative variability of subsequent, alpha-blocking event durations. The temporal association between electro-cortical field activation and regional cerebral blood flow (rCBF) led us...... to investigate whether the reduced variability of alpha-blocking durations with feedback is associated with a reduction in rCBF variability. Reduced variability in the rCBF response domain under EEG feedback control might have methodological implications for future brain-imaging studies. Visual stimuli were...... to quantify the variance-reducing effects of ACS across multiple, distributed areas of the brain. Both EEG and rCBF measures demonstrated decreased variability under ACS. This improved control was seen for localized as well as anatomically distributed rCBF measures....

  20. Comparison of cerebral blood flow data obtained by computed tomography (CT) perfusion with that obtained by xenon CT using 320-row CT.

    Science.gov (United States)

    Takahashi, Satoshi; Tanizaki, Yoshio; Kimura, Hiroaki; Akaji, Kazunori; Kano, Tadashige; Suzuki, Kentaro; Takayama, Youhei; Kanzawa, Takao; Shidoh, Satoka; Nakazawa, Masaki; Yoshida, Kazunari; Mihara, Ban

    2015-03-01

    Cerebral blood flow (CBF) data obtained by computed tomography perfusion (CTP) imaging have been shown to be qualitative data rather than quantitative, in contrast with data obtained by other imaging methods, such as xenon CT (XeCT) imaging. Thus, interpatient comparisons of CBF values themselves obtained by CTP may be inaccurate. In this study, we have compared CBF ratios as well as CBF values obtained from CTP-CBF data to those obtained from XeCT-CBF data for the same patients to determine CTP-CBF parameters that can be used for interpatient comparisons. The data used in the present study were obtained as volume data using 320-row CT. The volume data were applied to an automated region of interest-determining software (3DSRT, version 3.5.2 ) and converted to 59 slices of 2 mm interval standardized images. In the present study, we reviewed 10 patients with occlusive cerebrovascular diseases (CVDs) undergoing both CTP and XeCT in the same period. Our study shows that ratios of CBF measurements, such as hemodynamic stress distribution (perforator-to-cortical flow ratio of middle cerebral artery [MCA] region) or the left/right ratio for the region of the MCA, calculated using CTP data have been shown to correlate well with the same ratios calculated using XeCT data. These results suggest that such CBF ratios could be useful for generating interpatient comparisons of CTP-CBF data obtained by 320-row CT among patients with occlusive CVD.

  1. Regional cerebral blood flow assessed by 133Xe inhalation and emission tomography

    DEFF Research Database (Denmark)

    Shirahata, N; Henriksen, L; Vorstrup, S

    1985-01-01

    Regional cerebral blood flow (rCBF) in the cerebral hemispheres and the cerebellum was measured by single photon emission computed tomography with inhalation of 133Xe in 39 normal volunteers at test. The goal of this study was to assess the normal flow pattern and its variations. Five parallel...

  2. Inspiratory loading and limb blood flow in COPD: The modulating effects of resting lung hyperinflation.

    Science.gov (United States)

    Berton, Danilo C; de Castro, Marina A; Merola, Pietro; Benedetto, Igor; Castilho, Mariah; Vieira, Paulo J C; Knorst, Marli M; Neder, J Alberto

    2016-07-01

    Inspiratory resistive loading (IRL) may have deleterious cardiocirculatory effects leading to poor peripheral perfusion in severely-hyperinflated patients with COPD. Nineteen patients (13 severely-hyperinflated with inspiratory capacity/total lung capacity ratio≤0.28) underwent calf blood flow (CBF) measurements by venous occlusion plethysmography at rest and during IRL at 60% maximal inspiratory pressure. Severely-hyperinflated patients had lower resting CBF and greater calf vascular resistance (CVR) than moderately-hyperinflated patients (phyperinflated patients had markedly reduced CBF (p=0.01). Opposite to our main hypothesis, however, IRL did not further reduce CBF in these patients (p>0.05). Conversely, it significantly decreased CBF and increased CVR in moderately-hyperinflated patients; in fact, end-trial CBF and CVR did not differ between the groups (p>0.05). In conclusion, marked impairments in resting appendicular blood flow in severely-hyperinflated patients with COPD were seen only after acute IRL in less hyperinflated patients. These findings set the stage for studies investigating the effects of lung deflation on peripheral hemodynamics in patients with severe hyperinflation.

  3. Effects of peritumoural oedema on cerebral blood flow and cerebrovascular reactivity in patients with alert consciousness

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chia-Cheng [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Department of Neurosurgery, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan 236-0004; Kuwana, Nobumasa; Ito, Susumu [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Ikegami, Tadashi [Department of Radiology, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Yamamoto, Isao [Department of Neurosurgery, Yokohama City University School of Medicine, Yokohama (Japan)

    1999-11-01

    The effects of peritumoural oedema on cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in 18 patients with alert consciousness. Hemispheric mean CBF was measured by performing first-pass radionuclide angiography using technetium-99m hexamethylpropylene amine oxime. CVR was measured as the percentage change from the baseline mean CBF value after acetazolamide administration. Patients were classified into three groups according to the severity of peritumoural oedema. The mean CBF of both hemispheres in each group was not significantly different from that of age-matched controls. CVR was preserved in patients with mild peritumoural oedema (n=6), but was significantly (P<0.01) reduced in patients with moderate (n=7) and severe peritumoural oedema (n=5). No significant correlation was found between the degree of midline shift and the mean CVR of both hemispheres (P=0.09). Surgical removal of the tumour significantly (P<0.05) improved the impaired CVR, although the mean CBF did not change. Administration of glucocorticoid improved the impaired CVR, without a change in the mean CBF, in a patient with a metastatic brain tumour. We conclude that CVR is impaired by the development of peritumoural oedema prior to changes in mean CBF. (orig.)

  4. Pressure passive cerebral blood flow and breakdown of the blood-brain barrier in experimental fetal asphyxia

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Tweed, W A

    1979-01-01

    Cerebral blood flow (CBF) was studied in non-exteriorized near-term sheep fetuses using the radioactive microsphere technique. By partially occluding the umbilical vessels for a period of 1--1 1/2 hours a progressive and severe asphyxia with a final arterial pH of 6.90 was achieved. Varying...

  5. Hepatic encephalopathy is associated with decreased cerebral oxygen metabolism and blood flow, not increased ammonia uptake

    DEFF Research Database (Denmark)

    Dam, Gitte; Keiding, Susanne; Munk, Ole L

    2013-01-01

    Studies have shown decreased cerebral oxygen metabolism (CMRO(2)) and blood flow (CBF) in patients with cirrhosis with hepatic encephalopathy (HE). It remains unclear, however, whether these disturbances are associated with HE or with cirrhosis itself and how they may relate to arterial blood...... ammonia concentration and cerebral metabolic rate of blood ammonia (CMRA). We addressed these questions in a paired study design by investigating patients with cirrhosis during and after recovery from an acute episode of HE type C. CMRO(2), CBF, and CMRA were measured by dynamic positron emission...

  6. Hyperventilation-induced reduction in cerebral blood flow: Assessment by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bednarczyk, E.M.; Rutherford, W.F.; Leisure, G.P.; Munger, M.A.; Panacek, E.A.; Miraldi, F.D.; Green, J.A. (Case Western Reserve Univ. School of Medicine, Cleveland, OH (USA))

    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.

  7. Changes in cerebral blood flow after transjugular intrahepatic portosystemic shunt can help predict the development of hepatic encephalopathy: An arterial spin labeling MR study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Zhang, Long Jiang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China); Wang, Ze [Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3900 Chestnut St., Philadelphia, PA 19104 (United States); Qi, Rong Feng; Shi, Donghong [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China); Wang, Li [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Fan, Xinxin [Research Institute of General Surgery, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China); Lu, Guang Ming, E-mail: kevinzhanglongjiang@yahoo.com.cn [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu 210002 (China)

    2012-12-15

    Background and purpose: Cerebral blood flow (CBF) changes after transjugular intrahepatic portosystemic shunt (TIPS) are still unclear. Our aim is to assess the TIPS-induced CBF changes and their potential clinical significance using the arterial spin labeling (ASL) perfusion magnetic resonance imaging. Materials and methods: Nine cirrhotic patients underwent ASL 1–8 days before and 4–7 days after TIPS. CBF was calculated at each voxel and mean CBF values were computed in the whole brain, gray matter and white matter. Changes of CBFs before and after TIPS were compared by paired t-test. Results: Voxel-wise results showed CBF diffusely increased in patients after TIPS, but no region with significant decrease in CBF was found, nor was any significant mean CBF difference detected in the whole brain, gray matter and white matter. Six patients out of nine showed a global CBF increase of 9–39%; one patient presented a global CBF decrease of 6%; another two showed a global CBF decrease of 16% and 31% respectively. Follow-up studies showed that the two patients with greatly decreased global CBF suffered from multiple episodes of overt hepatic encephalopathy (OHE) after TIPS and one died of OHE. Conclusions: CBF derived from noninvasive ASL MRI could be used as a useful biomarker to predict the development of OHE through consecutively tracking CBF changes in patients with inserted TIPS. Increased CBFs in many cortical regions could be common effects of the TIPS procedure, while decreased global CBF following TIPS might indicate the development of OHE.

  8. Acute marijuana effects on rCBF and cognition: a PET study.

    Science.gov (United States)

    O'Leary, D S; Block, R I; Flaum, M; Schultz, S K; Boles Ponto, L L; Watkins, G L; Hurtig, R R; Andreasen, N C; Hichwa, R D

    2000-11-27

    The effects of smoking marijuana on cognition and brain function were assessed with PET using H2(15)O. Regional cerebral blood flow (rCBF) was measured in five recreational users before and after smoking a marijuana cigarette, as they repeatedly performed an auditory attention task. Blood flow increased following smoking in a number of paralimbic brain regions (e.g. orbital frontal lobes, insula, temporal poles) and in anterior cingulate and cerebellum. Large reductions in rCBF were observed in temporal lobe regions that are sensitive to auditory attention effects. Brain regions showing increased rCBF may mediate the intoxicating and mood-related effects of smoking marijuana, whereas reduction of task-related rCBF in temporal lobe cortices may account for the impaired cognitive functions associated with acute intoxication.

  9. Smoking normalizes cerebral blood flow and oxygen consumption after 12-hour abstention

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Gjedde, Albert; Imamirad, Nasrin

    2015-01-01

    measurements of cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO2) in 12 smokers who had refrained from smoking overnight, and in a historical group of nonsmokers, testing the prediction that overnight abstinence results in widespread, coupled reductions of CBF and CMRO2. At the end......Acute nicotine administration stimulates [14C]deoxyglucose trapping in thalamus and other regions of rat brain, but acute effects of nicotine and smoking on energy metabolism have rarely been investigated in human brain by positron emission tomography (PET). We obtained quantitative PET...... of the abstention period, global grey-matter CBF and CMRO2 were both reduced by 17% relative to nonsmokers. At 15 minutes after renewed smoking, global CBF had increased insignificantly, while global CMRO2 had increased by 11%. Regional analysis showed that CMRO2 had increased in the left putamen and thalamus...

  10. Effects of acetazolamide on cerebral blood flow and brain tissue oxygenation

    DEFF Research Database (Denmark)

    Lassen, N A; Friberg, L; Kastrup, J

    1987-01-01

    Oral administration of 1 g of acetazolamide to 8 normal subjects studied at sea level and in normoxia caused an acute increase in cerebral blood flow (CBF). During the subsequent prolonged oral treatment with 1 g of acetazolamide daily, CBF returned to normal within 2 days. The alveolar CO2 tension...... decreased gradually to 70% of the control value, indicating hyperventilation. At sea level hyperventilation will not increase brain oxygenation significantly in normal man, as the arterial oxygen content only increases minimally, while CBF is unchanged. At high altitude the beneficial effects...... of acetazolamide on the symptoms of acute mountain sickness may well be due to an improved oxygen supply to the brain, as hyperventilation will, at the low ambient PO2, cause a significant increase of the arterial oxygen content, while CBF presumably is unaffected by the drug. During hypoxia at high altitude...

  11. Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Larsson, Henrik B W; Hansen, Adam E;

    2012-01-01

    PURPOSE: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). MATERIALS AND METHODS: Repeated CBF measurements were performed in 17 healthy, young...... subjects using three different MRI techniques: arterial spin labeling (ASL), dynamic contrast enhanced T1 weighted perfusion MRI (DCE) and phase contrast mapping (PCM). All MRI measurements were performed within the same session. In 10 of the subjects repeated CBF measurements by (15) O labeled water PET......L/100 g/min, 16.2% and 4.8%, for DCE 43.0 mL/100 g/min, 20.0%, 15.1% and for PET 41.9 mL/100 g/min, 16.5% and 11.9%, respectively. Only for DCE and PCM a significant positive correlation between measurements was demonstrated. CONCLUSION: These findings confirm large between subject variability in CBF...

  12. Quantifying regional cerebral blood flow by N-isopropyl-P-[I-123]iodoamphetamine (IMP) using a ring type single-photon emission computed tomography system

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N.; Odano, I.; Ohkubo, M. [Niigata Univ. (Japan)] [and others

    1994-05-01

    We developed a more accurate quantitative measurement of regional cerebral blood flow (rCBF) with the microsphere model using N-isopropyl-p-[I-123] iodoamphetamine (IMP) and a ring type single photon emission computed tomography (SPECT) system. SPECT studies were performed in 17 patients with brain diseases. A dose of 222 MBq (6 mCi) of [I-123]IMP was injected i.v., at the same time a 5 min period of arterial blood withdrawal was begun. SPECT data were acquired from 25 min to 60 min after tracer injection. For obtaining the brain activity concentration at 5 min after IMP injection, total brain counts collections and one minute period short time SPECT studies were performed at 5, 20, and 60 min. Measurement of the values of rCBF was calculated using short time SPECT images at 5 min (rCBF), static SPECT images corrected with total cerebral counts (rCBF{sub Ct}.) and those corrected with reconstructed counts on short time SPECT images (rCBF{sub Cb}). There was a good relationship (r=0.69) between rCBF and rCBF{sub Ct}, however, rCBF{sub Ct} tends to be underestimated in high flow areas and overestimated in low flow areas. There was better relationship between rCBF and rCBF{sub Cb}(r=0.92). The overestimation and underestimation shown in rCBF{sub Ct} was considered to be due to the correction of reconstructed counts using a total cerebral time activity curve, because of the kinetic behavior of [I-123]IMP was different in each region. We concluded that more accurate rCBF values could be obtained using the regional time activity curves.

  13. Regional neurohypophysial and hypothalamic blood flow in rats during hypercapnia

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, R.M. Jr.; Myers, C.L.; Page, R.B.

    1988-08-01

    Regional cerebral blood flow (rCBF) was measured in the neurohypophysis and hypothalamus in normocapnic and hypercapnic rats using (/sup 14/C)isopropyliodoamphetamine. Rats were surgically prepared using nitrous oxide and halothane and placed in plaster restraining casts. Hypercapnia was produced by increasing the fractional concentration of inspired CO/sub 2/ (FICO/sub 2/). rCBF in normocapnic rats was higher in the paraventricular nucleus, supraoptic nucleus, median eminence, and neural lobe than rates previously measured by use of diffusible tracers. During hypercapnia blood flow increased linearly with arterial PCO/sub 2/ (PACO/sub 2/) in all regions except the median eminence and neural lobe, which were not affected by hypercapnia. When rats were pretreated with phentolamine (1 mg/kg) to block the alpha-adrenergic receptors, blood flow in the median eminence and neural lobe increased significantly during hypercapnia. We conclude that blood flow in the cell bodies of the paraventricular nucleus and supraoptic nucleus is regulated differently during hypercapnia than blood flow in the nerve terminals in the median eminence and neural lobe. Furthermore, vasodilation produced by increased CO/sub 2/ is offset by alpha-receptor stimulation in the median eminence and neural lobe.

  14. Absolute cerebral blood flow and blood volume measured by magnetic resonance imaging bolus tracking: comparison with positron emission tomography values

    DEFF Research Database (Denmark)

    Østergaard, Leif; Smith, D F; Vestergaard-Poulsen, Peter;

    1998-01-01

    The authors determined cerebral blood flow (CBF) with magnetic resonance imaging (MRI) of contrast agent bolus passage and compared the results with those obtained by O-15 labeled water (H215O) and positron emission tomography (PET). Six pigs were examined by MRI and PET under normo......- and hypercapnic conditions. After dose normalization and introduction of an empirical constant phi Gd, absolute regional CBF was calculated from MRI. The spatial resolution and the signal-to-noise ratio of CBF measurements by MRI were better than by the H215O-PET protocol. Magnetic resonance imaging cerebral...... blood volume (CBV) estimates obtained using this normalization constant correlated well with values obtained by O-15 labeled carbonmonooxide (C15O) PET. However, PET CBV values were approximately 2.5 times larger than absolute MRI CBV values, supporting the hypothesized sensitivity of MRI to small...

  15. Cerebral effects of scalp cooling and extracerebral contribution to calculated blood flow values using the intravenous 133Xe technique

    DEFF Research Database (Denmark)

    Friberg, L; Kastrup, J; Hansen, M

    1986-01-01

    values. With a two-compartmental analysis of the wash-out curves during cooling there was a significant reduction of the CBF indices f1, representing mainly fast blood flow in the grey matter and f2, representing blood flow in the slowly perfused white matter and extracerebral structures. The reduction...

  16. Nicotine effects on regional cerebral blood flow in awake, resting tobacco smokers.

    Science.gov (United States)

    Domino, E F; Minoshima, S; Guthrie, S; Ohl, L; Ni, L; Koeppe, R A; Zubieta, J K

    2000-12-01

    The hypothesis for this research was that regional cerebral blood flow (rCBF) would increase following nasal nicotine administration to overnight abstinent tobacco smokers in relationship to the known brain distribution of nicotinic cholinergic receptors (nAChRs). Nine male and nine female healthy adult smokers were studied. They abstained overnight from tobacco products for 10 or more hours prior to study the next morning. Nicotine nasal spray was given in doses of 1-2.5 mg total with half in each nostril while the subject was awake and resting in a supine position. Oleoresin of pepper solution in a similar volume was used as an active placebo to control for the irritating effects of nicotine. Both substances were given single blind to the subjects. Positron emission tomography (PET) with H(2)(15)O was used to measure rCBF. The data from each subject volunteer were normalized to global activity to better assess regional brain changes. Both nasal nicotine and pepper spray produced similar increases in CBF in somesthetic area II, consistent with the irritant effects of both substances. The mean rCBF effects of nasal pepper were subtracted from those of nasal nicotine to determine the actions of nicotine alone. The latter produced increases in rCBF in the thalamus, pons, Brodman area 17 of the visual cortex, and cerebellum. Some brain areas that contain a large number of nAChRs, such as the thalamus, showed an increase in CBF. Other areas that have few nAChRs, such as the cerebellum, also showed an increase in relative CBF. The hippocampal/parahippocampal areas showed greater regional decreases (left) and lesser increases (right) in CBF that correlated with the increase in plasma arterial nicotine concentrations. The results obtained indicate complex primary and secondary effects of nicotine in which only some regional brain CBF changes correlate with the known distribution of nAChR. No gender differences were noted.

  17. Interactive effects of vascular risk burden and advanced age on cerebral blood flow

    Directory of Open Access Journals (Sweden)

    Katherine eBangen

    2014-07-01

    Full Text Available 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.

  18. Regional cerebral blood flow and glucose metabolism following transient forebrain ischemia.

    Science.gov (United States)

    Pulsinelli, W A; Levy, D E; Duffy, T E

    1982-05-01

    Progressive brain damage after transient cerebral ischemia may be related to changes in postischemic cerebral blood flow and metabolism. Regional cerebral blood flow (rCBF) and cerebral glucose utilization (rCGU) were measured in adult rats prior to, during (only rCBF), and serially after transient forebrain ischemia. Animals were subjected to 30 minutes of forebrain ischemia by occluding both common carotid arteries 24 hours after cauterizing the vertebral arteries. Regional CBF was measured by the indicator-fractionation technique using 4-iodo-[14C]-antipyrine. Regional CGU was measured by the 2-[14C]deoxyglucose method. The results were correlated with the distribution and progression of ischemic neuronal damage in animals subjected to an identical ischemic insult. Cerebral blood flow to forebrain after 30 minutes of moderate to severe ischemia (less than 10% control CBF) was characterized by 5 to 15 minutes of hyperemia; rCBF then fell below normal and remained low for as long as 24 hours. Post-ischemic glucose utilization in the forebrain, except in the hippocampus, was depressed below control values at 1 hour and either remained low (neocortex, striatum) or gradually rose to normal (white matter) by 48 hours. In the hippocampus, glucose utilization equaled the control value at 1 hour and fell below control between 24 and 48 hours. The appearance of moderate to severe morphological damage in striatum and hippocampus coincided with a late rise of rCBF above normal and with a fall of rCGU; the late depression of rCGU was usually preceded by a period during which metabolism was increased relative to adjacent tissue. Further refinement of these studies may help identify salvageable brain after ischemia and define ways to manipulate CBF and metabolism in the treatment of stroke.

  19. Continuous measurement of cerebral cortical blood flow by laser-Doppler flowmetry in a rat stroke model

    Energy Technology Data Exchange (ETDEWEB)

    Dirnagl, U.; Kaplan, B.; Jacewicz, M.; Pulsinelli, W. (Cornell Univ. Medical College, New York, NY (USA))

    1989-10-01

    Laser-Doppler flowmetry (LDF), a new method allowing instantaneous, continuous, and noninvasive measurements of microcirculatory blood flow in a small tissue sample, was evaluated for its accuracy in monitoring regional cerebral blood flow (rCBF) in the cortical microcirculation after focal cerebral ischemia. Wistar and spontaneously hypertensive rats (SHR, n = 19) were subjected to permanent occlusion of the middle cerebral and common carotid arteries. Absolute rCBF in a tissue sample of the ischemic hemisphere was measured autoradiographically with ({sup 14}C)iodoantipyrine as a tracer and compared to rCBF measured by LDF. Additionally, the percent change in rCBF between baseline and ischemic values was compared for both methods. Absolute rCBF values recorded with LDF correlated poorly (r = 0.54) with ({sup 14}C)iodoantipyrine measurements. In contrast LDF readings expressed as a percentage of ischemic vs. preocclusion readings (relative LDF readings) correlated very well (r = 0.91) with the percent change in (14C)iodoantipyrine measurements. We conclude that LDF does not provide accurate measurements of absolute rCBF values but this method allows accurate measurements of changes in rCBF due to induction of focal cerebral ischemia.

  20. Continuous measurement of cerebral cortical blood flow by laser-Doppler flowmetry in a rat stroke model.

    Science.gov (United States)

    Dirnagl, U; Kaplan, B; Jacewicz, M; Pulsinelli, W

    1989-10-01

    Laser-Doppler flowmetry (LDF), a new method allowing instantaneous, continuous, and noninvasive measurements of microcirculatory blood flow in a small tissue sample, was evaluated for its accuracy in monitoring regional cerebral blood flow (rCBF) in the cortical microcirculation after focal cerebral ischemia. Wistar and spontaneously hypertensive rats (SHR, n = 19) were subjected to permanent occlusion of the middle cerebral and common carotid arteries. Absolute rCBF in a tissue sample of the ischemic hemisphere was measured autoradiographically with [14C]iodoantipyrine as a tracer and compared to rCBF measured by LDF. Additionally, the percent change in rCBF between baseline and ischemic values was compared for both methods. Absolute rCBF values recorded with LDF correlated poorly (r = 0.54) with [14C]iodoantipyrine measurements. In contrast LDF readings expressed as a percentage of ischemic vs. preocclusion readings (relative LDF readings) correlated very well (r = 0.91) with the percent change in [14C]iodoantipyrine measurements. We conclude that LDF does not provide accurate measurements of absolute rCBF values but this method allows accurate measurements of changes in rCBF due to induction of focal cerebral ischemia.

  1. Effects of Ginkgo biloba on cerebral blood flow assessed by quantitative MR perfusion imaging: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Mashayekh, Ameneh; Pham, Dzung L.; Yousem, David M.; Dizon, Mercedes; Barker, Peter B.; Lin, Doris D.M. [Johns Hopkins University School of Medicine, Department of Radiology, Division of Neuroradiology, Baltimore, MD (United States)

    2011-03-15

    Extract of Ginkgo biloba (EGb), a dietary supplement used for a number of conditions including dementia, has been suggested to increase cerebral blood flow (CBF). The purpose of this study was to determine if changes in CBF could be detected by dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in elderly human subjects taking EGb. DSC-MRI was performed in nine healthy men (mean age 61 {+-} 10 years) before and after 4 weeks of 60 mg EGb taken twice daily. One subject underwent six consecutive scans to evaluate intrasubject reproducibility. CBF values were computed before and after EGb, and analyzed at three different levels of spatial resolution, using voxel-based statistical parametric mapping (SPM), and regions of interest in different lobes, and all regions combined. Normalized intrasubject CBF (nCBF) measurements had a standard deviation of 7% and 4% in gray and white matter (WM) regions, respectively. SPM using an uncorrected, voxel-level threshold of P {<=} 0.001 showed a small CBF increase in the left parietal-occipital region. CBF in individual lobar regions did not show any significant change post-EGb, but all regions combined showed a significant increase of non-normalized CBF after EGb (15% in white and 13% in gray matter, respectively, P {<=} 0.0001). nCBF measured by DSC-MRI has good intrasubject reproducibility. In this small cohort of normal elderly individuals, a mild increase in CBF is found in the left parietal-occipital WM after EGb, as well as a small but statistically significant increase in global CBF. (orig.)

  2. Presymptomatic cerebral blood flow changes in CHMP2B mutation carriers of familial frontotemporal dementia (FTD-3), measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders;

    2012-01-01

    OBJECTIVES: To assess functional changes measured by cerebral blood flow (CBF) in the presymptomatic stage of frontotemporal dementia linked to chromosome 3 (FTD-3) caused by a truncating mutation in CHMP2B. DESIGN: Case-control study. SETTING: A memory clinic and tertiary referrals centre...... changes in brain tissue perfusion were measured as CBF with two different MR techniques, gradient echo (GRE) and spin echo (SE), focusing on CBF in all cerebral vessels (GRE) and cerebral capillaries (SE), respectively. As planned, data analysis included co-registration of perfusion images to structural T...

  3. Stimulus rate dependence of regional cerebral blood flow in human striate cortex, demonstrated by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fox, P.T.; Raichle, M.E.

    1984-05-01

    The purpose of this investigation was to determine the relationship between the repetition rate of a simple sensory stimulus and regional cerebral blood flow (rCBF) in the human brain. Positron emission tomography (PET), using intravenously administered H/sub 2/(/sup 15/)O as the diffusible blood-flow tracer, was employed for all CBF measurements. The use of H/sub 2/(/sup 15/)O with PET allowed eight CBF measurements to be made in rapid sequence under multiple stimulation conditions without removing the subject from the tomograph. Nine normal volunteers each underwent a series of eight H2(/sup 15/)O PET measurements of CBF. Initial and final scans were made during visual deprivation. The six intervening scans were made during visual activation with patterned-flash stimuli given in random order at 1.0-, 3.9-, 7.8-, 15.5-, 33.1-, and 61-Hz repetition rates. The region of greatest rCBF increase was determined. Within this region the rCBF was determined for every test condition and then expressed as the percentage change from the value of the initial unstimulated scan (rCBF% delta). In every subject, striate cortex rCBF% delta varied systematically with stimulus rate. Between 0 and 7.8 Hz, rCBF% delta was a linear function of stimulus repetition rate. The rCBF response peaked at 7.8 Hz and then declined. The rCBF% delta during visual stimulation was significantly greater than that during visual deprivation for every stimulus rate except 1.0 Hz. The anatomical localization of the region of peak rCBF response was determined for every subject to be the mesial occipital lobes along the calcarine fissure, primary visual cortex. Stimulus rate is a significant determinant of rCBF response in the visual cortex. Investigators of brain responses to selective activation procedures should be aware of the potential effects of stimulus rate on rCBF and other measurements of cerebral metabolism.

  4. Model estimation of cerebral hemodynamics between blood flow and volume changes: a data-based modeling approach.

    Science.gov (United States)

    Wei, Hua-Liang; Zheng, Ying; Pan, Yi; Coca, Daniel; Li, Liang-Min; Mayhew, J E W; Billings, Stephen A

    2009-06-01

    It is well known that there is a dynamic relationship between cerebral blood flow (CBF) and cerebral blood volume (CBV). With increasing applications of functional MRI, where the blood oxygen-level-dependent signals are recorded, the understanding and accurate modeling of the hemodynamic relationship between CBF and CBV becomes increasingly important. This study presents an empirical and data-based modeling framework for model identification from CBF and CBV experimental data. It is shown that the relationship between the changes in CBF and CBV can be described using a parsimonious autoregressive with exogenous input model structure. It is observed that neither the ordinary least-squares (LS) method nor the classical total least-squares (TLS) method can produce accurate estimates from the original noisy CBF and CBV data. A regularized total least-squares (RTLS) method is thus introduced and extended to solve such an error-in-the-variables problem. Quantitative results show that the RTLS method works very well on the noisy CBF and CBV data. Finally, a combination of RTLS with a filtering method can lead to a parsimonious but very effective model that can characterize the relationship between the changes in CBF and CBV.

  5. Quantitative measurements of cerebral blood flow in volume imaging PET scanners

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.; Shao, L.; Freifelder, R.; Karp, J.S.; Ragland, J.D. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    1995-08-01

    Quantitative measurements of Cerebral Blood Flow (CBF) are performed in a volume imaging PET Scanner by means of moderate activity infusions. In equilibrium infusions, activations are measured by scanning over 10 minutes with 16 minute activations. Typical measured whole brain CBF values are 37{+-}8 ml/min/100g, close to the value of 42 ml/min/100g reported by other groups using this method. For ramped infusions, scanning over 4 minutes with 5 minute activations results in whole brain CBFs of 49 {+-} 9 ml/min/100g, close to the Kety and Schmidt value of 50 ml/min/100g. Both equilibrium and ramped infusion methods have been used to study face and word memory in human subjects. Both methods were able to detect significant activations in regions implicated in human memory. The authors conclude that precise quantitation of regional CBF is achieved using both methods, and that ramped infusions also provide accurate measures of CBF. In addition a simplified protocol for ramped infusion studies has been developed. In this method the whole brain tissue time activity curve generated from dynamic scanning is replaced by an appropriately scaled camera coincidence countrate curve. The resulting whole brain CBF values are only 7% different from the dynamic scan and fit results. Regional CBFs (rCBF) may then be generated from the summed image (4.25 minutes) using a count density vs flow lookup table.

  6. Effects of 5-HT1B/1D receptor agonist rizatriptan on cerebral blood flow and blood volume in normal circulation.

    Science.gov (United States)

    Okazawa, Hidehiko; Tsuchida, Tatsuro; Pagani, Marco; Mori, Tetsuya; Kobayashi, Masato; Tanaka, Fumiko; Yonekura, Yoshiharu

    2006-01-01

    To investigate the vasoconstrictor effect of 5-hydroxytryptamine (5-HT1B/1D) receptor agonists for migraine treatment, changes in cerebral blood flow (CBF) and blood volume induced by rizatriptan were assessed by positron emission tomography (PET). Eleven healthy volunteers underwent PET studies before and after rizatriptan administration. Dynamic PET data were acquired after bolus injection of H2(15)O to analyze CBF and arterial-to-capillary blood volume (V0) images using the three-weighted integral method. After a baseline scan, three further acquisitions were performed at 40 to 50, 60 and 70 to 80 mins after drug administration. Global and regional differences in CBF and V0 between conditions were compared using absolute values in the whole brain and cortical regions, as well as statistical parametric mapping (SPM) analysis. The global and regional values for CBF and V0 decreased significantly after rizatriptan administration compared with the baseline condition. However, both values recovered to baseline within 80 mins after treatment. The maximal reduction in global CBF and V0 was approximately 13% of baseline value. The greatest decrease in CBF was observed approximately 60 mins after drug administration, whereas the maximal reduction in V0 was observed approximately 5 mins earlier. Statistical parametric mapping did not highlight any regional differences between conditions. Thus, in brain circulation, rizatriptan caused significant CBF and V0 decreases, which are consistent with the vasoconstrictor effect of triptans on the large cerebral arteries. The gradual recovery in the late phase from the maximal CBF and V0 decrease suggests that rizatriptan does not affect the cerebral autoregulatory response in small arteries induced by CBF reduction.

  7. Primary Somatosensory Cortices Contain Altered Patterns of Regional Cerebral Blood Flow in the Interictal Phase of Migraine

    Science.gov (United States)

    Hodkinson, Duncan J.; Veggeberg, Rosanna; Wilcox, Sophie L.; Scrivani, Steven; Burstein, Rami; Becerra, Lino; Borsook, David

    2015-01-01

    The regulation of cerebral blood flow (CBF) is a complex integrated process that is critical for supporting healthy brain function. Studies have demonstrated a high incidence of alterations in CBF in patients suffering from migraine with and without aura during different phases of attacks. However, the CBF data collected interictally has failed to show any distinguishing features or clues as to the underlying pathophysiology of the disease. In this study we used the magnetic resonance imaging (MRI) technique—arterial spin labeling (ASL)—to non-invasively and quantitatively measure regional CBF (rCBF) in a case-controlled study of interictal migraine. We examined both the regional and global CBF differences between the groups, and found a significant increase in rCBF in the primary somatosensory cortex (S1) of migraine patients. The CBF values in S1 were positively correlated with the headache attack frequency, but were unrelated to the duration of illness or age of the patients. Additionally, 82% of patients reported skin hypersensitivity (cutaneous allodynia) during migraine, suggesting atypical processing of somatosensory stimuli. Our results demonstrate the presence of a disease-specific functional deficit in a known region of the trigemino-cortical pathway, which may be driven by adaptive or maladaptive functional plasticity. These findings may in part explain the altered sensory experiences reported between migraine attacks. PMID:26372461

  8. Primary Somatosensory Cortices Contain Altered Patterns of Regional Cerebral Blood Flow in the Interictal Phase of Migraine.

    Directory of Open Access Journals (Sweden)

    Duncan J Hodkinson

    Full Text Available The regulation of cerebral blood flow (CBF is a complex integrated process that is critical for supporting healthy brain function. Studies have demonstrated a high incidence of alterations in CBF in patients suffering from migraine with and without aura during different phases of attacks. However, the CBF data collected interictally has failed to show any distinguishing features or clues as to the underlying pathophysiology of the disease. In this study we used the magnetic resonance imaging (MRI technique-arterial spin labeling (ASL-to non-invasively and quantitatively measure regional CBF (rCBF in a case-controlled study of interictal migraine. We examined both the regional and global CBF differences between the groups, and found a significant increase in rCBF in the primary somatosensory cortex (S1 of migraine patients. The CBF values in S1 were positively correlated with the headache attack frequency, but were unrelated to the duration of illness or age of the patients. Additionally, 82% of patients reported skin hypersensitivity (cutaneous allodynia during migraine, suggesting atypical processing of somatosensory stimuli. Our results demonstrate the presence of a disease-specific functional deficit in a known region of the trigemino-cortical pathway, which may be driven by adaptive or maladaptive functional plasticity. These findings may in part explain the altered sensory experiences reported between migraine attacks.

  9. Heat stress redistributes blood flow in arteries of the brain during dynamic exercise.

    Science.gov (United States)

    Sato, Kohei; Oue, Anna; Yoneya, Marina; Sadamoto, Tomoko; Ogoh, Shigehiko

    2016-04-01

    We hypothesized that heat stress would decrease anterior and posterior cerebral blood flow (CBF) during exercise, and the reduction in anterior CBF would be partly associated with large increase in extracranial blood flow (BF). Nine subjects performed 40 min of semirecumbent cycling at 60% of the peak oxygen uptake in hot (35°C; Heat) and thermoneutral environments (25°C; Control). We evaluated BF and conductance (COND) in the external carotid artery (ECA), internal carotid artery (ICA), and vertebral artery (VA) using ultrasonography. During the Heat condition, ICA and VA BF were significantly increased 10 min after the start of exercise (P brain arteries to exercise, which resulted in an alteration in the distribution of cardiac output. Moreover, a hyperthermia-induced increase in extracranial BF might compromise anterior CBF during exercise with heat stress.

  10. Blood flow and vascular reactivity during attacks of classic migraine--limitations of the Xe-133 intraarterial technique

    Energy Technology Data Exchange (ETDEWEB)

    Skyhoj Olsen, T.; Lassen, N.A.

    1989-01-01

    The present study reports cerebral blood flow (CBF) measurements in 11 patients during attacks of classic migraine (CM)--migraine with aura. In 6 and 7 patients, respectively, cerebral vascular reactivity to increased blood pressure and to hypocapnia was also investigated during the CM attacks. The Xenon-133 intraarterial injection technique was used to measure CBF. In this study, based in part on previously published data, methodological limitations, in particular caused by scattered radiation (Compton scatter), are critically analysed. Based on this analysis and the results of the CBF studies it is concluded: During CM attacks CBF appears to decrease focally in the posterior part of the brain to a level around 20 ml/100 g/min which is consistent with a mild degree of ischemia. Changes of CBF in focal low flow areas are difficult to evaluate accurately with the Xe-133 technique. In most cases true CBF may change 50% or more in the low flow areas without giving rise to significantly measurable changes of CBF. This analysis suggests that the autoregulation response cannot be evaluated in the low flow areas with the technique used while the observations are compatible with the concept that a vasoconstrictive state, unresponsive to hypocapnia, prevails in the low flow areas during CM attacks. The gradual increase in size of the low flow area seen in several cases may be interpreted in two different ways. A spreading process may actually exist. However, due to Compton scatter, a gradual decrease of CBF in a territory that does not increase in size will also appear as a gradually spreading low flow area when studied with the Xe-133 intracarotid technique.

  11. Measurement of cerebral blood flow by intravenous xenon-133 technique and a mobile system. Reproducibility using the Obrist model compared to total curve analysis

    DEFF Research Database (Denmark)

    Schroeder, T; Holstein, P; Lassen, N A

    1986-01-01

    was considerably more reproducible than CBF level. Using a single detector instead of five regional values averaged as the hemispheric flow increased standard deviation of CBF level by 10-20%, while the variation in asymmetry was doubled. In optimal measuring conditions the two models revealed no significant...... differences, but in low flow situations the artifact model yielded significantly more stable results. The present apparatus, equipped with 3-5 detectors covering each hemisphere, offers the opportunity of performing serial CBF measurements in situations not otherwise feasible.......The recent development of a mobile 10 detector unit, using i.v. Xenon-133 technique, has made it possible to perform repeated bedside measurements of cerebral blood flow (CBF). Test-retest studies were carried out in 38 atherosclerotic subjects, in order to evaluate the reproducibility of CBF level...

  12. Regional partition coefficient of water in patients with cerebrovascular disease and its effect on rCBF assessment

    OpenAIRE

    Hirata, Kenji; Hattori, Naoya; Katoh, Chietsugu; Shiga, Tohru; KURODA, Satoshi; Kubo, Naoki; Usui, Reiko; Kuge, Yuji; Tamaki, Nagara

    2011-01-01

    Objective: Cerebral blood flow (CBF) estimation with C15O2 PET usually assumes a single tissue compartment model and a fixed brain-blood partition coefficient of water. However, the partition coefficient may change in pathological conditions. The purpose of this study was to investigate the changes of partition coefficient of water in pathological regions and its effect on regional CBF assessment. Methods: Study protocol included 22 patients with occlusive cerebrovascular disease to compare p...

  13. Effect of mild cognitive impairment and APOE genotype on resting cerebral blood flow and its association with cognition.

    Science.gov (United States)

    Wierenga, Christina E; Dev, Sheena I; Shin, David D; Clark, Lindsay R; Bangen, Katherine J; Jak, Amy J; Rissman, Robert A; Liu, Thomas T; Salmon, David P; Bondi, Mark W

    2012-08-01

    Using whole-brain pulsed arterial spin labeling magnetic resonance imaging, resting cerebral blood flow (CBF) was measured in 20 mild cognitive impairment (MCI; 11 ɛ3 and 9 ɛ4) and 40 demographically matched cognitively normal (CN; 27 ɛ3 and 13 ɛ4) participants. An interaction of apolipoprotein (APOE) genotype (ɛ3 and ɛ4) and cognitive status (CN and MCI) on quantified gray-matter CBF corrected for partial volume effects was found in the left parahippocampal and fusiform gyri (PHG/FG), right middle frontal gyrus, and left medial frontal gyrus. In the PHG/FG, CBF was elevated for CN ɛ4 carriers but decreased for MCI ɛ4 carriers. The opposite pattern was seen in frontal regions: CBF was decreased for CN ɛ4 carriers but increased for MCI ɛ4 carriers. Cerebral blood flow in the PHG/FG was positively correlated with verbal memory for CN ɛ4 adults (r=0.67, P=0.01). Cerebral blood flow in the left medial frontal gyrus was positively correlated with verbal memory for MCI ɛ4 adults (r=0.70, P=0.05). Findings support dynamic pathophysiologic processes in the brain associated with Alzheimer's disease risk and indicate that cognitive status and APOE genotype have interactive effects on CBF. Correlations between CBF and verbal memory suggest a differential neurovascular compensatory response in posterior and anterior cortices with cognitive decline in ɛ4 adults.

  14. Assessing regional cerebral blood flow in depression using 320-slice computed tomography.

    Directory of Open Access Journals (Sweden)

    Yiming Wang

    Full Text Available 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. Transcranial 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 rateand 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.

  15. Reassessing the clinical efficacy of two MR quantitative DSC PWI CBF algorithms following cross-calibration with PET images

    Science.gov (United States)

    Chen, Jean J.; Frayne, Richard; Smith, Michael R.

    2005-03-01

    Clinical cerebral blood flow (CBF) maps generated through dynamic- susceptibility contrast (DSC) magnetic resonance (MR) perfusion imaging are currently cross-calibrated with PET studies. The cross-calibration is achieved by rescaling the MR CBF values so that normal white matter CBF corresponds to 22 ml/100 g/min. Examples are provided in this paper to show how this rescaling procedure changes both the clinical interpretation of CBF maps and the manner by which the performance of a given deconvolution algorithm should be assessed. (i) Singular-value decomposition-based (SVD) algorithms produce absolute CBF estimates that are inherently under-estimated for all tissue mean transit times (MTT) but, after rescaling, will generate CBF maps that are over-estimated for MTT >4.8 s. (ii) In principle, frequency-domain modelling techniques are expected to be inherently less sensitive to contrast recirculation biases than the time-domain SVD algorithms. However, it is shown that both CBF algorithms become greatly less sensitive to distortions from recirculation after clinical cross-calibration through rescaling has been performed. It is concluded that, when rescaling procedures are employed, it is relatively more important to develop deconvolution algorithms that produce CBF estimates with accuracies that vary little with MTT than to produce algorithms that provide inherently more accurate CBF estimates, but whose relative accuracy varies significantly with MTT. A portion of this work was presented at the 2004 Annual Scientific Meeting of the ISMRM, 15-21 May, Kyoto, Japan.

  16. The effect of S. pneumoniae bacteremia on cerebral blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Pedersen, Michael; Brandt, Christian T.; Knudsen, Gitte Moos

    2008-01-01

    In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally...

  17. Global cerebral blood flow and metabolism during acute hyperketonemia in the awake and anesthetized rat

    DEFF Research Database (Denmark)

    Linde, Rasmus; Hasselbalch, Steen G.; Topp, Simon;

    2006-01-01

    In the human setting, it has been shown that acute increase in the concentration of ketone bodies by infusion of beta-hydroxybutyrate increased the cerebral blood flow (CBF) without affecting the overall cerebral metabolic activity. The mechanism by which this effect of ketone bodies was mediated...

  18. Regional cerebral blood flow distribution in newly diagnosed schizophrenia and schizophreniform disorder

    DEFF Research Database (Denmark)

    Rubin, P; Holm, S; Madsen, P L

    1994-01-01

    Regional cerebral blood flow distribution (rCBF) in 24 first admissions with schizophrenia or schizophreniform disorder and in 17 healthy volunteers was examined. Single photon emission computed tomography with a brain-retained tracer, technetium-99m-d,l-hexamethyl-propylene amine oxime, was used...

  19. Regional cerebral blood flow changes associated with clitorally induced orgasm in healthy women

    NARCIS (Netherlands)

    Georgiadis, Janniko R.; Kortekaas, Rudie; Kuipers, Rutger; Nieuwenburg, Arie; Pruim, Jan; Reinders, A. A. T. Simone; Holstege, Gert

    2006-01-01

    There is a severe lack of knowledge regarding the brain regions involved in human sexual performance in general, and female orgasm in particular. We used [(15)O]-H(2)O positron emission tomography to measure regional cerebral blood flow (rCBF) in 12 healthy women during a nonsexual resting state, cl

  20. Blood flow and microgravity

    Science.gov (United States)

    Bureau, Lionel; Coupier, Gwennou; Dubois, Frank; Duperray, Alain; Farutin, Alexander; Minetti, Christophe; Misbah, Chaouqi; Podgorski, Thomas; Tsvirkun, Daria; Vysokikh, Mikhail

    2017-01-01

    The absence of gravity during space flight can alter cardio-vascular functions partially due to reduced physical activity. This affects the overall hemodynamics, and in particular the level of shear stresses to which blood vessels are submitted. Long-term exposure to space environment is thus susceptible to induce vascular remodeling through a mechanotransduction cascade that couples vessel shape and function with the mechanical cues exerted by the circulating cells on the vessel walls. Central to such processes, the glycocalyx - i.e. the micron-thick layer of biomacromolecules that lines the lumen of blood vessels and is directly exposed to blood flow - is a major actor in the regulation of biochemical and mechanical interactions. We discuss in this article several experiments performed under microgravity, such as the determination of lift force and collective motion in blood flow, and some preliminary results obtained in artificial microfluidic circuits functionalized with endothelium that offer interesting perspectives for the study of the interactions between blood and endothelium in healthy condition as well as by mimicking the degradation of glycocalyx caused by long space missions. A direct comparison between experiments and simulations is discussed. xml:lang="fr"

  1. Poor agreement between transcranial Doppler and near-infrared spectroscopy-based estimates of cerebral blood flow changes in sepsis

    DEFF Research Database (Denmark)

    Toksvang, Linea N; Plovsing, Ronni R; Petersen, Marie W;

    2014-01-01

    BACKGROUND: Continuous monitoring of cerebral blood flow (CBF) may be valuable in critically ill patients with sepsis. In this study, we compared spatially resolved near-infrared spectroscopy (NIRS) to transcranial Doppler ultrasound (TCD)-derived estimates of noradrenaline-associated changes...... in CBF in such patients. METHODS: Mean arterial blood pressure (MAP) was elevated by increasing the noradrenaline infusion rate in eight mechanically ventilated, critically ill patients diagnosed with severe sepsis or septic shock. The associated changes in CBF were assessed by simultaneous ipsilateral......-derived estimates with a relative bias of 14% and limits of agreement of -18% to 45% change in CBF. CONCLUSION: Our findings stress that TCD and NIRS cannot be used interchangeably for monitoring changes in cerebral haemodynamics in critically ill patients with sepsis receiving vasopressor treatment...

  2. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures

    Energy Technology Data Exchange (ETDEWEB)

    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. Subcortical cerebral blood flow and metabolic changes elicited by cortical spreading depression in rat

    Energy Technology Data Exchange (ETDEWEB)

    Mraovitch, S.; Calando, Y.; Goadsby, P.J.; Seylaz, J. (Laboratoire de Recherches Cerebrovasculaire, Paris (France))

    1992-06-01

    Changes in cerebral cortical perfusion (CBF{sub LDF}), local cerebral blood flow (lCBF) and local cerebral glucose utilization (lCGU) elicited by unilateral cortical spreading depression (SD) were monitored and measured in separate groups of rats anesthetized with {alpha}-chloralose. CBF{sub LDF} was recorded with laser Doppler flowmetry, while lCBF and lCGU were measured by the quantitative autoradiographic ({sup 14}C)iodoantipyrine and ({sup 14}C)-2-deoxyglucose methods, respectively. SD elicited a wave of hyperemia after a latency of 2 to 3 min followed by an oligemic phase. Ninety minutes following the onset of SD cortical lCBF and lCGU were essentially the same as on the contralateral side and in sham-treated rats. However, alteration in the lCBF and lCGU in upper and lower brainstem persisted. The present results demonstrate that long-lasting cerebrovascular and metabolic alterations take place within the subcortical regions following SD. These regions provide an attractive site to integrate observations in man concerning spreading depression and the aura of migraine with the other features of the syndrome. 19 refs., 2 figs., 1 tab.

  4. Exercise intensity modulates the change in cerebral blood flow following aerobic exercise in chronic stroke.

    Science.gov (United States)

    Robertson, Andrew D; Crane, David E; Rajab, A Saeed; Swardfager, Walter; Marzolini, Susan; Shirzadi, Zahra; Middleton, Laura E; MacIntosh, Bradley J

    2015-08-01

    The mechanisms supporting functional improvement by aerobic exercise following stroke remain incompletely understood. This study investigated how cycling intensity and aerobic fitness influence cerebral blood flow (CBF) following a single exercise session. Thirteen community-living stroke survivors performed 20 min of semi-recumbent cycling at low and moderate intensities (40-50 and 60-70 % of heart rate reserve, respectively) as determined from an exercise stress test. CBF was quantified by arterial spin labeling MRI at baseline, as well as 30 and 50 min post-exercise. An intensity-dependent effect was observed in the right post-central and supramarginal gyri up to 50 min after exercise (uncorrected p Aerobic fitness was directly related to posterior cingulate and thalamic CBF, and inversely related to precuneal CBF at rest (R (2) ≥ 0.75); however, no relationship between fitness and the post-exercise change in CBF was observed. Divergent changes in regional CBF were observed in the right parietal cortex following low- and moderate-intensity exercise, which suggests that intensity of prescribed exercise may be useful in optimizing rehabilitation.

  5. Cerebral blood flow reactivity to hyperventilation in children with spontaneous occlusion of the circle of Willis (moyamoya disease)

    Energy Technology Data Exchange (ETDEWEB)

    Isobe, Masanori; Kuroda, Satoshi; Kamiyama, Hiroyasu; Abe, Hiroshi (Hokkaido Univ., Sapporo (Japan). School of Medicine); Mitumori, Kenji

    1992-04-01

    To elucidate the relationship between cerebral blood flow (CBF) after hyperventilation (HV) and the re-build-up phenomenon on the encephaloelectrogram (EEG) in children with moyamoya disease, comparative study of CBF immediately after HV and CBF after administration of acetazolamide (Diamox) was examined. CBF was measured by means of single photon emission CT (SPECT) using the {sup 133}Xe inhalation method. The subjects were 11 children (21 hemispheres) with moyamoya disease who were divided into two groups as follows: Bypass group; who underwent STA-MCA anastomosis with other synangiosis. Non-bypass group; who underwent only some synangiosis such as EDAS, EMAS and EMS. Regional CBF (rCBF) after HV of the frontal lobes in the non-bypass group had an evident tendency to show low perfusion compared with CBF in other regions. The correlation between low perfusion area after HV, and areas where the increase of rCB is less after administration of acetazolamide became clear. The strongest relation was observed between low perfusion after HV and re-build-up phenomenon on EEG. On the other hand, rCBF after HV of the frontal lobes in the bypass group had, compared with other regions, no tendency to show low perfusion. From this study and our previous reports, it is assumed that there is some hemodynamics insufficiency in the frontal lobes of the non-bypass group. The reason why the reduction of rCBF was less after HV especially in the frontal lobes of the bypass group is still unknown. But, most of anterior branches of STA were used for the anastomosis and the craniotomy of the bypass group was made in a more anterior position than that of the non-bypass group. These surgical procedures are estimated to bring about a much better collateral blood flow to the frontal lobes. (author).

  6. Quantitative measurement of cerebral blood flow during hypothermia with a time-resolved near-infrared technique

    Science.gov (United States)

    Fazel Bakhsheshi, Mohammad; Diop, Mamadou; St Lawrence, Keith; Lee, Ting-Yim

    2012-02-01

    Hypothermia, in which the brain is cooled to 32-33 °C, has been shown to be neuroprotective for brain injury caused by hypoxia-ischemia, head trauma, or neonatal asphyxia. Neuroprotective effect of Hypothermia is partly due to suppression of brain metabolism and cerebral blood flow (CBF). The ability to measure CBF at the bedside provides a means of detecting, and thereby preventing, secondary ischemia during neuro intensive care before brain injury occurs. The purpose of the present study is to investigate the ability of a time-resolved near-infrared (TR-NIR) bolus-tracking method using indocyanine green as an intravascular flow tracer to measure CBF during cooling in a newborn animal model. For validation, CBF was independently measured by computed tomography (CT) perfusion. The results show a good agreement between CBF obtained with the two methods (R2 ~ 0.84, Δ ~ 5.84 ml. min -1.100 g -1, 32-38.5 °C), demonstrating the ability of the TR-NIR technique to non-invasively measure absolute CBF in-vivo during dynamic hypothermia. The TR-NIR technique reveals that CBF decreases from 54.3 +/- 5.4 ml. min -1.100 g -1, at normothermia (Tbrain of 38.5 °C), to 33.8 +/- 0.9 ml. min -1.100 g -1 at Tbrain of 32 °C during the hypothermia treatment.

  7. Microstructure and Cerebral Blood Flow within White Matter of the Human Brain: A TBSS Analysis.

    Directory of Open Access Journals (Sweden)

    Stéphanie Giezendanner

    Full Text Available 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.Diffusion tensor imaging and ASL were acquired in 43 healthy subjects (mean age = 26.3 years.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.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.

  8. CBF/CBV maps in normal volunteers studied with (15)O PET: a possible index of cerebral perfusion pressure.

    Science.gov (United States)

    Watabe, Tadashi; Shimosegawa, Eku; Kato, Hiroki; Isohashi, Kayako; Ishibashi, Mana; Hatazawa, Jun

    2014-10-01

    Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be used as an index of the local CPP. In this study, we investigated whether the CBF/CBV ratio differs among different brain structures under physiological conditions, by means of (15)O positron emission tomography. Nine healthy volunteers (5 men and 4 women; mean age, 47.0 ± 1.2 years) were studied by H2 (15)O bolus injection for CBF measurement and by C(15)O inhalation for CBV measurement. The CBF/CBV ratio maps were created by dividing the CBF images by the CBV images after anatomical normalization. Regions of interest were placed on the CBF/CBV maps and comparing the regions. The mean CBF/CBV ratio was highest in the cerebellum (19.3 ± 5.2/min), followed by the putamen (18.2 ± 3.9), pons (16.4 ± 4.6), thalamus (14.5 ± 3.3), cerebral cortices (13.2 ± 2.4), and centrum semiovale (11.5 ± 2.1). The cerebellum and putamen showed significantly higher CBF/CBV ratios than the cerebral cortices and centrum semiovale. We created maps of the CBF/CBV ratio in normal volunteers and demonstrated higher CBF/CBV ratios in the cerebellum and putamen than in the cerebral cortices and deep cerebral white matter. The CBF/CBV may reflect the local CPP and should be studied in hemodynamically compromised patients and in patients with risk factors for small-artery diseases of the brain.

  9. Time-dependent changes in cerebral blood flow after acetazolamide loading into patients with hemodynamic cerebral ischemia. Relationship to cerebral oxygen metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Masakazu [Iwate Medical Univ., Morioka (Japan). School of Medicine

    2001-10-01

    The aim of this study was to clarify the relationship between time-dependent changes in cerebral blood flow (CBF) after acetazolamide loading and cerebral oxygen metabolism (CMRO{sub 2}). The subjects consisted of 30 patients with severe stenosis or occlusion of either internal carotid, middle cerebral, or vertebro-basilar artery. Regional CBF was measured at the resting state and 6, 16 and 30 minutes after intravenous administration of 1 gram of acetazolamide using the positron emission tomography in combination with the [{sup 15}O] H{sub 2}O bolus-injection method. Prior to CBF study, regional cerebral oxygen extraction fraction (OEF) was measured using the [{sup 15}O] O{sub 2} inhalation method. Regional CMRO{sub 2} was calculated based on CBF and OEF. According to the time-dependent changes in CBF responses to acetazolamide loading, the CBF responses are classified into good response type, paradoxical response type, and poor response type. Good response type (CBF increase rate more than 20% 6 minutes after acetazolamide loading), paradoxical response type (decrease of CBF 6 minutes after acetazolamide loading) and poor response type (CBF increase rate less than 20% 6 minutes after acetazolamide loading) were identified in 39, 11 and 10 areas, respectively. Brain areas with good response type showed normal OEF and normal CMRO{sub 2}. Brain areas with paradoxical response type showed increased OEF and normal CMRO{sub 2}. Brain areas with poor response type showed normal OEF and decreased CMRO{sub 2}. In view of these findings, the writer concludes that sequential measurement of cerebral blood flow (CBF) after acetazolamide loading enables one to know the regional cerebral oxygen metabolic state in patients with hemodynamic ischemia, and CBF should be measured at an early stage after the administration of acetazolamide to accurately detect misery perfusion. (author)

  10. Low Cerebral Oxygen Consumption and Blood Flow in Patients With Cirrhosis and an Acute Episode of Hepatic Encephalopathy

    DEFF Research Database (Denmark)

    Iversen, Peter; Bak, Lasse Kristoffer; Waagepetersen, Helle Sønderby

    2009-01-01

    BACKGROUND & AIMS: It is unclear whether patients with hepatic encephalopathy (HE) have disturbed brain oxygen metabolism and blood flow. METHODS: We measured cerebral oxygen metabolism rate (CMRO(2)) by using (15)O-oxygen positron emission tomography (PET), and cerebral blood flow (CBF) by using....../min in patients with HE, 0.47 +/- 0.02 in patients without HE, and 0.49 +/- 0.03 in healthy subjects. CMRO(2) and CBF were correlated, and both variables correlated negatively with arterial ammonia concentration. Analysis of regional values, using individual magnetic resonance co-registrations, showed...... that the reductions in CMRO(2) and CBF in patients with HE were essentially generalized throughout the brain. CONCLUSIONS: The observations imply that reduced cerebral oxygen consumption and blood flow in cirrhotic patients with an acute episode of overt HE are associated with HE and not cirrhosis as such...

  11. Positron emission tomography/magnetic resonance hybrid scanner imaging of cerebral blood flow using 15O-water positron emission tomography and arterial spin labeling magnetic resonance imaging in newborn piglets

    DEFF Research Database (Denmark)

    Andersen, Julie B; Henning, William S; Lindberg, Ulrich;

    2015-01-01

    Abnormality in cerebral blood flow (CBF) distribution can lead to hypoxic-ischemic cerebral damage in newborn infants. The aim of the study was to investigate minimally invasive approaches to measure CBF by comparing simultaneous (15)O-water positron emission tomography (PET) and single TI pulsed...

  12. Regional cerebral blood flow in various types of brain tumor. Effect of the space-occupying lesion on blood flow in brain tissue close to and remote from tumor site

    DEFF Research Database (Denmark)

    Kuroda, K; Skyhøj Olsen, T; Lassen, N A

    1982-01-01

    Regional cerebral blood flow (rCBF) was measured in 23 patients with brain tumors using the 133Xe intra-carotid injection method and a 254 channel gamma camera. The glioblastomas (4) and astrocytomas (4) all showed hyperemia in the tumor and tumor-near region. This was also seen in several...... meningiomas (4 of 7 cases) in which most of the tumor itself did not receive any isotope. Brain metastases (6) usually had a low flow in the tumor and tumor-near region. The glioblastomas tended to show markedly bending 133Xe wash-out curves pointing to pronounced heterogeneity of blood flow. Most of the flow...... maps, regardless of the tumor types, showed widespread abnormalities of rCBF not only in the tumor region but also in the region remote from the tumor. It is concluded that measurement of rCBF cannot yield accurate differential diagnostic information, but that the widespread derangement of the brain...

  13. Repeated measurements of cerebral blood flow in the left superior temporal gyrus reveal tonic hyperactivity in patients with auditory verbal hallucinations: A possible trait marker

    Directory of Open Access Journals (Sweden)

    Philipp eHoman

    2013-06-01

    Full Text Available Background: The left superior temporal gyrus (STG has been suggested to play a key role in auditory verbal hallucinations in patients with schizophrenia. Methods: Eleven medicated subjects with schizophrenia and medication-resistant auditory verbal hallucinations and 19 healthy controls underwent perfusion magnetic resonance imaging with arterial spin labeling. Three additional repeated measurements were conducted in the patients. Patients underwent a treatment with transcranial magnetic stimulation (TMS between the first 2 measurements. The main outcome measure was the pooled cerebral blood flow (CBF, which consisted of the regional CBF measurement in the left superior temporal gyrus (STG and the global CBF measurement in the whole brain.Results: Regional CBF in the left STG in patients was significantly higher compared to controls (p < 0.0001 and to the global CBF in patients (p < 0.004 at baseline. Regional CBF in the left STG remained significantly increased compared to the global CBF in patients across time (p < 0.0007, and it remained increased in patients after TMS compared to the baseline CBF in controls (p < 0.0001. After TMS, PANSS (p = 0.003 and PSYRATS (p = 0.01 scores decreased significantly in patients.Conclusions: This study demonstrated tonically increased regional CBF in the left STG in patients with schizophrenia and auditory hallucinations despite a decrease in symptoms after TMS. These findings were consistent with what has previously been termed a trait marker of auditory verbal hallucinations in schizophrenia.

  14. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of {sup 99m}Tc-HMPAO single-photon emission tomography in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Chang Chia-Cheng; Kuwana, Nobumasa; Noji, Masato; Tanabe, Yutaka; Koike, Y. [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Ikegami, Tadashi [Department of Radiology, Yokohama Minami Kyosai Hospital, Yokohama (Japan)

    1998-09-01

    The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography ({sup 99m}Tc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using {sup 99m}Tc-HMPAO SPET is reliable in clinical evaluations. (orig.) With 3 tabs., 10 refs.

  15. The effect of EC-IC bypass surgery on resting cerebral blood flow and cerebrovascular reserve capacity studied with stable Xe-CT and acetazolamide test

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, T.; Kashiwagi, S.; Nakano, S.; Takasago, T.; Abiko, S.; Shiroyama, Y.; Hayashi, M.; Ito, H. (Yamaguchi Univ. School of Medicine (Japan). Dept. of Neurosurgery)

    1991-06-01

    Cerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) were measured by stable xenon computerized tomography (Xe-CT) and acetazolamide test in 15 patients with cerebrovascular disease before and after extracranial-intracranial (EC-IC) bypass surgery for minor stroke, reversible ischemic neurological deficit or transient ischemic attack. All had angiographically shown occlusive lesions of the major arterial trunk. In the present series, global analysis showed that the bypass did not increase the resting rCBF, but did increase the rCRC. We divided the patients into four groups according to the preoperative resting rCBF and rCRC. All 3 patients with normal resting rCBF and reduced rCRC showed postoperative improvement of rCRC. Of 6 patients with reduced CBF and reduced CRC, three had postoperative increase in resting CBF and four had increased CRC. One of two patients with reduced CBF and normal CRC showed only an increase in CRC. We propose that reduced CRC or reduced CBF with reduced CRC are criteria for selection of candidates for bypass surgery. We conclude that Xe-CT with the Diamox test is a useful and simple method for evaluating cerebral hemodynamics. Preoperative grouping with a combination of preoperative resting rCBF and preoperative rCRC is useful for predicting the effect of EC-IC bypass surgery. (orig.).

  16. Effect of sumatriptan on cerebral blood flow during migraine headache. Measurement by sequential SPECT used {sup 99m}Tc-ECD background subtraction method

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Takashi; Torihara, Yoshito; Tsuneyoshi, Noritaka; Ikeda, Yoshitomo [Miyazaki Social Insurance Hospital (Japan)

    2001-07-01

    The present study was designed to examine the effect of sumatriptan on regional cerebral blood flow (CBF) during migraine headache. Nine cases were examined by {sup 99m}Tc-ECD background subtraction method for the absolute value measurement of regional CBF before and after sumatriptan injection. rCBF except for occipital and perioccipital lobes, were increased 10-20% during migraine headache and significant decreases were observed by sumatriptan injection. Two cases of nine had transiently increased systemic blood pressure and cardiac pulse rate, however, all cases improved migraine headache after injection of sumatriptan. (author)

  17. Blood flow and vascular reactivity during attacks of classic migraine--limitations of the Xe-133 intraarterial technique

    DEFF Research Database (Denmark)

    Skyhøj Olsen, T; Lassen, N A

    1989-01-01

    The present study reports cerebral blood flow (CBF) measurements in 11 patients during attacks of classic migraine (CM)--migraine with aura. In 6 and 7 patients, respectively, cerebral vascular reactivity to increased blood pressure and to hypocapnia was also investigated during the CM attacks. T...

  18. rCBF to distant areas in the acute and chronic stages of unilateral cerebrovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Toru; Tamada, Tsutomu; Gyoten, Masayuki; Imai, Shigeki; Kajihara, Yasumasa [Kawasaki Medical School, Kurashiki, Okayama (Japan). School of Medicine; Fukuda, Atsuhiro [Kawasaki Medical School, Kurashiki, Okayama (Japan). Clinical Care Center; Miyanoki, Syo [Kobe Univ. (Japan). School of Medicine

    2002-09-01

    In 14 patients with unilateral cerebrovascular disease, regional cerebral blood flow (CBF) to distant areas in the acute and chronic stages was evaluated by SPECT with {sup 123}I-IMP. In the acute stage, rCBF in distant areas was decreased in all patients. In the chronic stage, a decrease in rCBF was observed in the contralateral cerebellar hemisphere in 50% of unilateral cerebral hemispheric lesions, in the ipsilateral thalamus in 42.9% of cerebral cortical lesions, and in the ipsilateral cortex in 57.1% of subcortical lesions. The decreased rCBF in distant areas even in the chronic stage suggested the involvement of organic changes in the pathologic condition in this stage. (author)

  19. Cerebral extraction of N-13 ammonia: its dependence on cerebral blood flow and capillary permeability, surface area product. [Dogs; monkeys

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.E.; Huang, S.C.; Kuhl, D.E.; Hoffman, E.J.; Slin, C.

    1979-01-01

    /sup 13/N-labeled ammonia was used to investigate: (1) the cerebral extraction and clearance of ammonia; (2) the mechanicsm by which capillaries accommodate changes in cerebral blood flow (CBF); and (3) its use for the measure of CBF. This was investigated by measuring the single pass extraction of /sup 13/NH/sub 3/ in rhesus monkeys during P/sub a/CO/sub 2/ induced changes in CBF, and with dog studies using in vitro tissue counting techniques to examine /sup 13/NH/sub 3/ extraction in gray and white matter, mixed tissue, and cerebellum during variations in CBF produced by combinations of embolization, local brain compression, and changes in P/sub a/CO/sub 2/. The single pass extraction fraction of /sup 13/NH/sub 3/ varied from about 70 to 20% over a CBF range of 12 to 140cc/min/100gms. Capillary permeability-surface area product (PS) estimates from this data and the dog experiments show PS increasing with CBF. The magnitude and rate of increase in PS with CBF was highest in gray matter > mixed tissue > white matter. Tissue extraction of /sup 13/NH/sub 3/ vs CBF relationship was best described by a unidirectional transport model in which CBF increases by both recruitment of capillaries and by increases of blood velocity in open capillaries. Glutamine synthetase, which incorporates /sup 13/NH/sub 3/ into glutamine, appears to be anatomically located in astrocytes in general and specifically in the astrocytic pericapillary end-feet that are in direct contact with gray and white matter capillaries. The net /sup 13/NH/sub 3/ extraction subsequent to an i.v. injection increases nonlinearly with CBF. Doubling or halving basal CBF produced from 40 to 50% changes in the /sup 13/N tissue concentrations with further increases in CBF associated with progressively smaller changes in /sup 13/N concentrations. /sup 13/NH/sub 3/ appears to be a good tracer for the detection of cerebral ischemia with positron tomography but exhibits a poor response at high values of CBF.

  20. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E;

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were...... studied both during a seizure and (in the same setting) in the interictal period; six patients were studied only in the interictal period, and one patient was studied only during a seizure. Studies during seizures all showed marked flow increases in areas presumed to participate in the seizure activity....... This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal...

  1. Physiological activation of the human cerebral cortex during auditory perception and speech revealed by regional increases in cerebral blood flow

    DEFF Research Database (Denmark)

    Lassen, N A; Friberg, L

    1988-01-01

    Specific types of brain activity as sensory perception auditory, somato-sensory or visual -or the performance of movements are accompanied by increases of blood flow and oxygen consumption in the cortical areas involved with performing the respective tasks. The activation patterns observed...... by measuring regional cerebral blood flow CBF after intracarotid Xenon-133 injection are reviewed with emphasis on tests involving auditory perception and speech, and approach allowing to visualize Wernicke and Broca's areas and their contralateral homologues in vivo. The completely atraumatic tomographic CBF...

  2. Cerebral blood flow, oxidative metabolism and cerebrovascular carbon dioxide reactivity in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten; Strauss, Gitte Irene; Thomsen, Gerda;

    2002-01-01

    BACKGROUND: The optimal arterial carbon dioxide tension (P(a)CO(2)) in patients with acute bacterial meningitis (ABM) is unknown and controversial. The objective of this study was to measure global cerebral blood flow (CBF), cerebrovascular CO(2) reactivity (CO(2)R), and cerebral metabolic rates...... to baseline ventilation, whereas CMR(glu) increased. CONCLUSION: In patients with acute bacterial meningitis, we found variable levels of CBF and cerebrovascular CO(2) reactivity, a low a-v DO(2), low cerebral metabolic rates of oxygen and glucose, and a cerebral lactate efflux. In these patients...

  3. Regional cerebral blood flow change in a case of Alzheimer's disease with musical hallucinations.

    Science.gov (United States)

    Mori, Takaaki; Ikeda, Manabu; Fukuhara, Ryuji; Sugawara, Yoshifumi; Nakata, Shigeru; Matsumoto, Naomi; Nestor, Peter J; Tanabe, Hirotaka

    2006-06-01

    We examined alteration of regional cerebral blood flow (rCBF) in a case of Alzheimer's disease (AD) patient with musical hallucination. To detect regions related to musical hallucination, single-photon emission computed tomography (SPECT) imaging of the patient and nine sex, age, and cognitive function-matched AD patients without delusions and hallucinations were compared using statistical parametric mapping 99 (SPM99). In comparison with controls, the patient had increased rCBF in left temporal regions and left angular gyrus. This profile could be relevant to the neuroanatomical basis of musical hallucinations.

  4. Differences in regional cerebral blood flow during musical and verbal hallucinations.

    Science.gov (United States)

    Izumi, Yukiyo; Terao, Takeshi; Ishino, Yoichi; Nakamura, Jun

    2002-11-30

    A 51-year-old male patient suffered from both musical and verbal hallucinations with insight. We performed three single photon emission computed tomographic scans with the patient in different conditions: baseline without hallucinations, musical hallucinations, and verbal hallucinations. Clearly, different patterns of regional cerebral blood flow (rCBF) were observed during musical and verbal hallucinations. The findings suggest that musical and verbal hallucinations are associated with different patterns of rCBF, possibly reflecting the different causes of the two types of hallucinations.

  5. Focal increase of blood flow in the cerebral cortex of man during vestibular stimulation

    DEFF Research Database (Denmark)

    Friberg, L; Olsen, T S; Roland, P E

    1985-01-01

    This study is an attempt to reveal projection areas for vestibular afferents to the human brain. Changes in regional cerebral blood flow (rCBF) were measured over 254 cortical regions during caloric vestibular stimulation with warm water (44 degrees C). rCBF was measured when the external auditory...... meatus was irrigated with water at body temperature as a control to vestibular stimulation. During vestibular stimulation there was only a single cortical area, located in the superior temporal region, which showed a consistent focal activation in the hemisphere contralateral to the stimulated side...

  6. Asymmetry of cerebral blood flow in patients with senile dementia of Alzheimer type by SPECT using I-123 IMP

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Hisayuki; Hanyu, Haruo; Kobayashi, Yasutaka; Hatano, Nobuyoshi; Katsunuma, Hideyo; Suzuki, Takanari; Amino, Saburo (Tokyo Medical Coll. (Japan))

    1990-12-01

    Regional cerebral blood flow (rCBF) was determined by single photon emission CT (SPECT) with N-isopropyl-p-({sup 123}I)iodoamphetamine in 22 patients with clinically diagnosed senile dementia of Alzheimer type (SDAT) and in 18 age matched controls. We calculated asymmetry indices (AIs) of rCBF for matched right-left regions of interest. rCBF of parietal lobe in SDAT patients was significantly most laterally asymmetrycal, but the least in occipital lobe. Lateral asymmetry of rCBF in SDAT patients correlated with asymmetry of language and visuospatial functions; decreased rCBF in the left parietal lobe was associated with language dysfunction, and that in the right parietal lobe, with viduospatial dysfunction. Furthermore cerebellar AIs correlated negatively with those of the cerebral hemisphere and lower frontal region in SDAT patients. The results demonstrate that rCBF measurement by {sup 123}I-IMP SPECT is useful to detect lateral asymmetry in reduction of rCBF in SDAT. (author).

  7. Cerebral Blood Flow Measured by Arterial Spin Labeling MRI as a Preclinical Marker of Alzheimer’s Disease

    Science.gov (United States)

    Wierenga, Christina E.; Hays, Chelsea C.; Zlatar, Zvinka Z.

    2017-01-01

    There is growing recognition that cerebral hypoperfusion is related to the pathogenesis of Alzheimer’s disease (AD), implicating the measurement of cerebral blood flow (CBF) as a possible biomarker of AD. The ability to identify the earliest and most reliable markers of incipient cognitive decline and clinical symptoms is critical to develop effective preventive strategies and interventions for AD. Arterial spin labeling (ASL) magnetic resonance imaging (MRI) measures CBF by magnetically labeling arterial water and using it as an endogenous tracer. Studies using ASL MRI in humans indicate that CBF changes are present several years before the development of the clinical symptoms of AD. Moreover, ASL-measured CBF has been shown to distinguish between cognitively normal individuals, adults at risk for AD, and persons diagnosed with AD. Some studies indicate that CBF may even be sensitive for predicting cognitive decline and conversion to mild cognitive impairment and AD over time. Taken together, evidence suggests that the current staging models of AD biomarker pathology should incorporate early changes in CBF as a useful biomarker, possibly present even earlier than amyloid β accumulation. Though still a research tool, ASL imaging is a promising non-invasive and reliable method with the potential to serve as a future clinical tool for the measurement of CBF in preclinical AD. PMID:25159672

  8. Reduced blood flow response to acetazolamide reflects pre-existing vasodilation and decreased oxygen metabolism in major cerebral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Hiroshi; Okazawa, Hidehiko; Kishibe, Yoshihiko; Sugimoto, Kanji; Takahashi, Masaaki [Research Institute, Shiga Medical Center, 5-4-30 Moriyama, Moriyama-city, Shiga 524-8524 (Japan)

    2002-10-01

    A decrease in the cerebral blood flow (CBF) response to acetazolamide may indicate an increase in cerebral blood volume (CBV) caused by reduced perfusion pressure in patients with major cerebral artery steno-occlusive lesions. However, a decrease in cerebral metabolic rate of oxygen (CMRO{sub 2}) caused by ischemic changes may also decrease the CBF response to acetazolamide by decreasing the production of carbon dioxide. The purpose of this study was to determine whether the values of CBV and CMRO{sub 2} are independent predictors of the CBF response to acetazolamide in major cerebral arterial occlusive disease. We used positron emission tomography to study 30 patients with major cerebral artery steno-occlusive lesions. The CBF response to acetazolamide was assessed by measuring baseline CBF and CBF 10 min after an intravenous injection of 1 g of acetazolamide. Multivariate analysis was used to test the independent predictive value of the CBV and CMRO{sub 2} at baseline with respect to the percent change in CBF during acetazolamide administration. Both increased CBV and decreased CMRO{sub 2} were significant and independent predictors of the reduced CBF response to acetazolamide. CBV accounted for 25% of the variance in the absolute change in CBF during acetazolamide administration and 42% of the variance in the percent change in CBF, whereas CMRO{sub 2} accounted for 19% and 4% of the variance, respectively. In patients with major cerebral arterial occlusive disease, a decrease in CMRO{sub 2} may contribute to the reduced CBF response to acetazolamide, although an increase in CBV appears to be the major contributing factor. (orig.)

  9. Effects of aging on cerebral blood flow, oxygen metabolism, and blood oxygenation level dependent responses to visual stimulation.

    Science.gov (United States)

    Ances, Beau M; Liang, Christine L; Leontiev, Oleg; Perthen, Joanna E; Fleisher, Adam S; Lansing, Amy E; Buxton, Richard B

    2009-04-01

    Calibrated functional magnetic resonance imaging (fMRI) provides a noninvasive technique to assess functional metabolic changes associated with normal aging. We simultaneously measured both the magnitude of the blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) responses in the visual cortex for separate conditions of mild hypercapnia (5% CO(2)) and a simple checkerboard stimulus in healthy younger (n = 10, mean: 28-years-old) and older (n = 10, mean: 53-years-old) adults. From these data we derived baseline CBF, the BOLD scaling parameter M, the fractional change in the cerebral metabolic rate of oxygen consumption (CMRO(2)) with activation, and the coupling ratio n of the fractional changes in CBF and CMRO(2). For the functional activation paradigm, the magnitude of the BOLD response was significantly lower for the older group (0.57 +/- 0.07%) compared to the younger group (0.95 +/- 0.14%), despite the finding that the fractional CBF and CMRO(2) changes were similar for both groups. The weaker BOLD response for the older group was due to a reduction in the parameter M, which was significantly lower for older (4.6 +/- 0.4%) than younger subjects (6.5 +/- 0.8%), most likely reflecting a reduction in baseline CBF for older (41.7 +/- 4.8 mL/100 mL/min) compared to younger (59.6 +/- 9.1 mL/100 mL/min) subjects. In addition to these primary responses, for both groups the BOLD response exhibited a post-stimulus undershoot with no significant difference in this magnitude. However, the post-undershoot period of the CBF response was significantly greater for older compared to younger subjects. We conclude that when comparing two populations, the BOLD response can provide misleading reflections of underlying physiological changes. A calibrated approach provides a more quantitative reflection of underlying metabolic changes than the BOLD response alone.

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

    Science.gov (United States)

    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.

  11. Quantification of cerebral blood flow and its clinical usefulness. Application of SPECT to psychiatry

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Hiroshi; Uema, Takeshi; Kogure, Daisuke; Takano, Harumasa; Terada, Tomo [National Center Hospital for Mental, Nervous and Muscular Disorders, Kodaira, Tokyo (Japan)

    1998-10-01

    Brain perfusion SPECT using {sup 99m}Tc-ethyl-cysteinate dimer ({sup 99m}Tc-ECD) was applied to psychiatric diseases with aid of statistical parametric mapping (SPM) for analysis of data. To evaluate influence of aging on brain perfusion, noninvasive measurements of cerebral blood flow using {sup 99m}Tc-ECD were performed in 53 normal volunteers, aged 18 to 87 years old. Mean cerebral blood flow (mCBF) was 43.9{+-}5.0 ml/100 g/min and showed weak negative correlation with aging (r=-0.451). Perisylvian cerebral cortices and medial frontal areas including anterior cingulate gyri showed greater negative correlation than other areas. These findings suggest the necessity of age-matched control regional CBF (rCBF) data to investigate rCBF abnormality in patients. Four drug-naive schizophrenic patients showed flow decrease in bilateral frontal and superior temporal areas and a left infero-posterior temporal area. Haloperidol administration induced flow decrease in bilateral frontal and left parietal areas, while flow increase in bilateral striatal and right hippocampal areas. Ten aged depressive patients showed flow decrease in bilateral frontal and left temporo-parietal areas. Even after remission patients showed flow decrease in the left frontal area as compared with normal subjects. Remission induced flow increase in the right frontal, right parietal, and right orbitofrontal areas compared with depression. These results suggest that CBF measurements using {sup 99m}Tc-ECD are useful for objective evaluation of regional abnormality in brain function in psychiatric diseases. (author)

  12. Voxel-wise relationships between distribution volume ratio and cerebral blood flow: implications for analysis of β-amyloid images

    Science.gov (United States)

    Sojkova, Jitka; Goh, Joshua; Bilgel, Murat; Landman, Bennett; Yang, Xue; Zhou, Yun; An, Yang; Beason-Held, Lori L.; Kraut, Michael A.; Wong, Dean F.; Resnick, Susan M.

    2017-01-01

    Quantification of β-amyloid (Aβ) in vivo is often accomplished using the distribution volume ratio (DVR), based on a simplified reference tissue model. We investigated the local relationships between DVR and cerebral blood flow (CBF), as well as relative blood flow (R1), in nondemented older adults. Methods Fifty-five nondemented participants (mean age 78.5 years) in the Baltimore Longitudinal Study of Aging underwent 15O-H2O PET CBF and dynamic 11C-PiB-PET. 15O-H2O PET images were normalized and smoothed using SPM. A simplified reference tissue model with linear regression and spatial constraints was used to generate parametric DVR images. The DVR images were regressed on CBF images on a voxel-by-voxel basis using robust Biological Parametric Mapping, adjusting for age and sex (FDR p=0.05, k=50). DVR images were also regressed on R1 images, a measure of the transport rate constant from vascular space to tissue. All analyses were performed in the entire sample, and in high and low tertiles of mean cortical DVR. Results Voxel-based analyses showed that increased DVR is associated with increased CBF in frontal, parietal, temporal, and occipital cortices. However, this association appears to spare regions that typically show early β-amyloid (Aβ) deposition. A more robust relationship between DVR and CBF was observed in the lowest tertile of DVR, i.e., negligible cortical Aβ load, compared to the highest tertile of cortical DVR and Aβ load. Spatial distributions of the DVR-CBF and DVR-R1 correlations showed similar patterns. No reliable negative voxel-wise relationships between DVR and CBF or R1 were observed. Conclusion Robust associations between DVR and CBF at negligible Aβ levels, together with similar spatial distributions of DVR-CBF and DVR-R1 correlations, suggest that regional distribution of DVR reflects blood flow and tracer influx rather than pattern of Aβ deposition in those with minimal Aβ load. DVR-CBF associations in individuals with higher DVR

  13. Effects of W-CDMA 1950 MHz EMF emitted by mobile phones on regional cerebral blood flow in humans.

    Science.gov (United States)

    Mizuno, Yoko; Moriguchi, Yoshiya; Hikage, Takashi; Terao, Yasuo; Ohnishi, Takashi; Nojima, Toshio; Ugawa, Yoshikazu

    2009-10-01

    Use of the third generation mobile phone system is increasing worldwide. This is the first study to investigate the effects of the third generation system on regional cerebral blood flow (rCBF) in humans. We compared effects of the electromagnetic field (EMF) emitted from the Wideband Code Division Multiple Access (W-CDMA) cellular system versus sham control exposure on rCBF in humans. Nine healthy male volunteers participated in this study. Positron emission tomography (PET) scans were obtained before, during, and after unilateral 30 min EMF exposure. The subtraction analysis revealed no significant rCBF changes caused by the EMF conditions compared with the sham exposure, suggesting that EMF emitted by a third generation mobile phone does not affect rCBF in humans.

  14. Cerebral blood flow and liver function in patients with encephalopathy due to acute and chronic liver diseases

    DEFF Research Database (Denmark)

    Almdal, T; Schroeder, T; Ranek, L

    1989-01-01

    The purpose of the present investigation was to study changes in cerebral blood flow (CBF) in hepatic encephalopathy, to ascertain whether this was related to the changes in liver function and whether these changes gave any prognostic information. CBF, determined by the intravenous xenon-133 method......, and liver functions, assessed by the prothrombin index, bilirubin concentration, and the galactose elimination capacity, were studied in patients with acute fulminant liver failure and in patients with encephalopathy due to chronic liver diseases--that is, cirrhosis of various etiologies. The CBF range...... any differences between patients with acute or chronic liver diseases or the different degrees of hepatic encephalopathy. In conclusion, a marked reduction of the CBF was seen in hepatic encephalopathy, irrespective of the etiology of the disease....

  15. Interictal "patchy" regional cerebral blood flow patterns in migraine patients. A single photon emission computerized tomographic study

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, J; Iversen, Helle Klingenberg

    1994-01-01

    .28). There was no correlation between visual or quantitated abnormalities and age, duration of migraine, frequency of attacks or prophylactic medication. No correlation could be established between asymmetries and the usual side of headache or aura symptoms. Two conclusions emerged: (1) visual evaluation of interictal migraine......In 92 migraine patients and 44 healthy control subjects we recorded regional cerebral blood flow (rCBF) with single photon emission computerized tomography and (133) Xe inhalation or with i.v. (99m) Tc-HMPAO. Migraine patients were studied interictally. A quantitated analysis of right...... rCBF images is insufficient to pick up abnormalities; (2) almost 50% of the migraine sufferers had abnormal rCBF/asymmetries. However, these are discrete compared with those typically seen during the aura phase of a migraine attack. One explanation to the patchy rCBF patterns might...

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

    DEFF Research Database (Denmark)

    Kim, Yu-Sok; Seifert, Thomas; Brassard, Patrice

    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...... 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

  17. Epileptic Seizure Detection and Prediction Based on Continuous Cerebral Blood Flow Monitoring – a Review

    Directory of Open Access Journals (Sweden)

    Senay Tewolde

    2015-01-01

    Full Text Available 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.

  18. Magnetic Resonance Imaging Quantification of Regional Cerebral Blood Flow and Cerebrovascular Reactivity to Carbon Dioxide in Normotensive and Hypertensive Rats

    Science.gov (United States)

    Leoni, Renata F.; Paiva, Fernando F.; Henning, Erica C.; Nascimento, George C.; Tannús, Alberto; de Araujo, Draulio B.; Silva, Afonso C.

    2011-01-01

    Hypertension afflicts 25% of the general population and over 50% of the elderly. In the present work, arterial spin labeling MRI was used to non-invasively quantify regional cerebral blood flow (CBF), cerebrovascular resistance and CO2 reactivity in spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY), at two different ages (3 months and 10 months) and under the effects of two anesthetics, α-chloralose and 2% isoflurane (1.5 MAC). Repeated CBF measurements were highly consistent, differing by less than 10% and 18% within and across animals, respectively. Under α-chloralose, whole brain CBF at normocapnia did not differ between groups (young WKY: 61±3ml/100g/min; adult WKY: 62±4ml/100g/min; young SHR: 70±9ml/100g/min; adult SHR: 69±8ml/100g/min), indicating normal cerebral autoregulation in SHR. At hypercapnia, CBF values increased significantly, and a linear relationship between CBF and PaCO2 levels was observed. In contrast, 2% isoflurane impaired cerebral autoregulation. Whole brain CBF in SHR was significantly higher than in WKY rats at normocapnia (young SHR: 139±25ml/100g/min; adult SHR: 104±23ml/100g/min; young WKY: 55±9ml/100g/min; adult WKY: 71±19ml/100g/min). CBF values increased significantly with increasing CO2; however, there was a clear saturation of CBF at PaCO2 levels greater than 70 mmHg in both young and adult rats, regardless of absolute CBF values, suggesting that isoflurane interferes with the vasodilatory mechanisms of CO2. This behavior was observed for both cortical and subcortical structures. Under either anesthetic, CO2 reactivity values in adult SHR were decreased, confirming that hypertension, when combined with age, increases cerebrovascular resistance and reduces cerebrovascular compliance. PMID:21708273

  19. Regional cerebral blood flow pattern in normal young and aged volunteers: a {sup 99m}Tc-HMPAO SPET study

    Energy Technology Data Exchange (ETDEWEB)

    Catafau, A.M. [Dept. of Nuclear Medicine, Hospital Clinic, Univ. of Barcelona (Spain); Lomena, J. [Dept. of Nuclear Medicine, Hospital Clinic, Univ. of Barcelona (Spain); Pavia, J. [Dept. of Nuclear Medicine, Hospital Clinic, Univ. of Barcelona (Spain); Parellada, E. [Dept. of Psychiatry, Hospital Clinic, Univ. of Barcelona (Spain); Bernardo, M. [Dept. of Psychiatry, Hospital Clinic, Univ. of Barcelona (Spain); Setoain, J. [Dept. of Nuclear Medicine, Hospital Clinic, Univ. of Barcelona (Spain); Tolosa, E. [Dept. of Neurology, Hospital Clinic, Univ. of Barcelona (Spain)

    1996-10-01

    The aim of this study was to investigate the normal pattern of regional cerebral blood flow (rCBF) distribution in normal young and aged volunteers using technetium-99m hexamethylpropylene amine oxime ({sup 99m}-Tc-HMPAO) as a tracer. The region brain perfusion of young and aged subjects was compared, especially regarding rCBF differences due to age and gender, and interhemispheric rCBF asymmetries. Sixty-eight right-handed normal volunteers - 40 young (mean age 29.5{+-}6.3 years) and 28 aged (mean age 71.2{+-}4.3 years) - were included in the study. rCBF was estimated on the basis of a semiquantitative approach by means of a left-right index and two region/reference ratios, using the cerebellum and the whole brain activity as references. A good correlation between these two region/reference ratios was found (P<0.005 in all cerebral regions). The highest rCBF ratios corresponded to the cerebellum, followed by the occipital lobe. The remaining cortical regions (temporal, parietal, frontal and basal ganglia) showed slightly lower values. The white matter showed rCBF ratios substantially lower than the grey matter. In neighter young nor aged subjects were significant rCBF differences between the genders found in any of the two region/reference indices employed. Aged sugjects showed significantly lower rCBF ratios than young subjects in the left frontal lobe and in the posterior region of the left temporal lobe. In both young and aged subjects, lower perfusion was found in the left hemisphere, except for the white matter region in both age groups and the frontal lobe in the young subjects. Aged subjects presented a slightly higher interhemispheric asymmetry in the frontal lobe. However, interhemispheric asymmetry was minimal (-1.01% to 3.14%). Consequently, a symmetrical rCBF distribution can be assumed between homologous regions, independent of age. (orig.)

  20. Reproducibility of regional cerebral blood flow measurement at rest with autoradiography method using {sup 123}I-IMP and SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kyoko; Murata, Hajime; Maruno, Hirotaka; Mori, Kazuaki; Tsuchida, Shoichi [Toranomon Hospital, Tokyo (Japan)

    1997-05-01

    Reproducibility of regional cerebral blood flow (rCBF) values obtained by the autoradiography (ARG) method with one SPECT scan and one point arterial blood sampling at 10 min after {sup 123}I-N-isopropyl-p-iodoamphetamine (IMP) infusion was evaluated. The variation in the cross calibration factor between SPECT counts and well-type scintillation counts remained 2.2% for 13 months. The error in rCBF by sampling time difference was less than 3% when sampling time was within 10 min{+-}30 sec after infusion. There was a favorable correlation between the rCBF values in two separate resting scans measured by the ARG method in 10 patients (r=0.907). And the mean ratio of rCBF values by the second study to those by the first study in the cerebellum and cerebral lobes in 10 patients was 0.989{+-}0.056 (mean{+-}SD). There was no significant difference in rCBF values between two separate studies. Reproducibility of rCBF with the ARG method was proved to be good. The ARG method was thought to be useful for the assessment of treatment effects and clinical courses. (author)

  1. Hippocampal and Cerebral Blood Flow After Exercise Cessation in Master Athletes

    Directory of Open Access Journals (Sweden)

    Alfonso J. Alfini

    2016-08-01

    Full Text Available 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, 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.

  2. Multivariate evaluation of brain function by measuring regional cerebral blood flow and event-related potentials

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Yoshihiko; Mochida, Masahiko; Shutara, Yoshikazu; Nakagawa, Kazumi [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine; Nagata, Ken

    1998-07-01

    To measure the effect of events on human cognitive function, effects of odors by measurement regional cerebral blood flow (rCBF) and P300 were evaluated during the auditory odd-ball exercise. PET showed the increase in rCBF on the right hemisphere of the brain by coffee aroma. rCBF was measured by PET in 9 of right-handed healthy adults men, and P300 was by event-related potential (ERP) in each sex of 20 right-handed healthy adults. ERP showed the difference of the P300 amplitude between men and women, and showed the tendency, by odors except the lavender oil, that women had higher in the P300 amplitude than men. These results suggest the presence of effects on the cognitive function through emotional actions. Next, the relationship between rCBF and ERP were evaluated. The subjects were 9 of the right-handed healthy adults (average: 25.6{+-}3.4 years old). rCBF by PET and P300 amplitude by ERP were simultaneously recorded during the auditory odd-ball exercise using the tone-burst method (2 kHz of the low frequency aimed stimuli and 1 kHz of the high frequency non-aimed stimuli). The rCBF value was the highest at the transverse gyrus of Heschl and the lowest at the piriform cortex among 24 regions of interest (ROI) from both sides. The difference of P300 peak latent time among ROI was almost the same. The brain waves from Cz and Pz were similar and the average amplitude was highest at Pz. We found the high correlation in the right piriform cortex (Fz), and right (Fz, Cz) and left (Cz, Pz) transverse gyrus of Heschl between the P300 amplitude and rCBF. (K.H.)

  3. Evaluation of regional cerebral blood flow changes in normal aging using {sup 99m}Tc-ECD SPECT and Patlak method

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Shinji; Nandate, Yuka; Enya, Mayumi; Manabe, Tomoko; Goto, Hiroo; Hoshi, Hiroaki; Takahashi, Yukitoshi; Kato, Zenichiro; Kondo, Naomi [Gifu Univ. (Japan). School of Medicine

    1998-05-01

    Changes in regional cerebral blood flow (rCBF) were studied using {sup 99m}Tc-ECD SPECT and Patlak method in 47 subjects, aged 1 to 79 years (mean 28.5 years). No abnormal finding was found on MR imaging in the subjects. We obtained mean cerebral blood flow (mCBF) by means of Patlak method. rCBF was measured by positioning regions of interest (ROIs) in frontal lobe, parietal lobe, temporal lobe, occipital lobe, cerebellum and thalamus. The correlation coefficient between ages and mCBF was r=-0.897 (p<0.0001). mCBF of children was significantly higher (p<0.05), compared with adults. By dispersion analysis according to the groups of ages, significantly higher rCBF values were available in the frontal, parietal, temporal and occipital lobes during childhood than adulthood (p<0.05), but there were almost no significant differences of rCBF during childhood than adulthood in cerebellum and thalamus. (author)

  4. Involvement of calcitonin gene-related peptide in migraine: regional cerebral blood flow and blood flow velocity in migraine patients

    DEFF Research Database (Denmark)

    Lassen, L.H.; Jacobsen, V.B.; Haderslev, P.A.

    2008-01-01

    g/min) or placebo for 20 min was studied in 12 patients with migraine without aura outside attacks. Xenon-133 inhalation SPECT-determined regional cerebral blood flow (rCBF) and transcranial Doppler (TCD)-determined blood velocity (V-mean) in the middle cerebral artery (MCA), as well as the heart......Calcitonin gene-related peptide (CGRP)-containing nerves are closely associated with cranial blood vessels. CGRP is the most potent vasodilator known in isolated cerebral blood vessels. CGRP can induce migraine attacks, and two selective CGRP receptor antagonists are effective in the treatment...... of migraine attacks. It is therefore important to investigate its mechanism of action in patients with migraine. We here investigate the effects of intravenous human alpha-CGRP (h alpha CGRP) on intracranial hemodynamics. In a double-blind, cross-over study, the effect of intravenous infusion of haCGRP (2 mu...

  5. Increased 20-HETE synthesis explains reduced cerebral blood flow but not impaired neurovascular coupling after cortical spreading depression in rat cerebral cortex

    DEFF Research Database (Denmark)

    Fordsmann, Jonas Christoffer; ko, Rebecca; Choi, Hyun B

    2013-01-01

    Cortical spreading depression (CSD) is associated with release of arachidonic acid (AA), impaired neurovascular coupling, and reduced cerebral blood flow (CBF), caused by cortical vasoconstriction. We tested the hypothesis that the released AA is metabolized by the cytochrome P450 enzyme to produce...... neurovascular coupling after CSD. These findings suggest that CSD-induced increments in 20-HETE cause the reduction in CBF after CSD, and that the attenuation of stimulation-induced CBF responses after CSD has a different mechanism. We suggest that blockade of 20-HETE synthesis may be clinically relevant...

  6. Regional cerebral blood flow abnormalities in late-life depression. Relation to refractoriness and chronification

    Energy Technology Data Exchange (ETDEWEB)

    Awata, Shuichi; Konno, Michiko; Sato, Mitsumoto [Tohoku Univ., Sendai (Japan). School of Medicine; Ito, Hiroshi; Ono, Shuichi; Kawashima, Ryuta; Fukuda, Hiroshi

    1998-02-01

    We examined patterns of regional cerebral blood flow (rCBF) abnormalities in 18 patients with major depressive disorder in late life using single photon emission computed tomography (SPECT) and {sup 99m}Tc-hexamethyl-propylenamine oxime ({sup 99m}Tc-HMPAO). Compared with 13 age-matched controls, relative rCBF was significantly decreased bilaterally in the anterior cingulate gyrus, the prefrontal cortex, the temporal cortex, the parietal cortex, the hippocampus and the caudate nucleus. However, it was not correlated with the severity of depression or global cognitive dysfunction. In 10 patients with a prolonged depressive episode or prolonged residual symptoms (the refractory subgroup), robust and extensive decreases in rCBF were found compared with controls and the rCBF decreased significantly in the anterior cingulate gyrus and the prefrontal cortex compared with that in the non-refractory subgroup. In the non-reflactory subgroup, rCBF decreased significantly in the caudate nucleus and tended to decrease in the anterior cingulate gyrus compared with controls. These findings indicate that dysfunction of the limbic system, the cerebral association cortex and the caudate nucleus may be implicated in late-life depression and that robust and extensive hypoperfusion, especially in the anterior cingulate and the prefrontal regions, may relate to refractoriness or chronification of depression. (author). 60 refs.

  7. Laser speckle contrast reveals cerebral blood flow dynamics evoked by optogenetically controlled neuronal activity

    Science.gov (United States)

    Li, Nan; Thakor, Nitish V.; Pelled, Galit

    2013-03-01

    As a critical basis of functional brain imaging, neurovascular coupling describes the link between neuronal and hemodynamic changes. The majority of in vivo neurovascular coupling studies was performed by inducing sensory stimulation via afferent inputs. Unfortunately such an approach results in recruiting of multiple types of cells, which confounds the explanation of neuronal roles in stimulus evoked hemodynamic changes. Recently optogenetics has emerged to provide immediate control of neurons by exciting or inhibiting genetically engineered neurons expressing light sensitive proteins. However, there is a need for optical methods capable of imaging the concurrent hemodynamic changes. We utilize laser speckle contrast imaging (LSCI) to obtain high resolution display of cerebral blood flow (CBF) in the vicinity of the targeted neural population. LSCI is a minimally invasive method for imaging CBF in microvessels through thinned skull, and produces images with high spatiotemporal resolution, wide field of view. In the integrated system light sources with different wavelengths and band-passing/blocking filters were used to allow simultaneous optical manipulation of neuronal activities and optical imaging of corresponding CBF. Experimental studies were carried out in a rodent model expressing channalrhodopsin (ChR2) in excitatory neurons in the somatosensory cortex (S1). The results demonstrated significant increases of CBF in response to ChR2 stimulation (exciting neuronal firing) comparable to the CBF response to contralateral forepaw stimulation. The approach promises to be an exciting minimally invasive method to study neurovascular coupling. The complete system provides a novel approach for broad neuroscience applications.

  8. New insights into coupling and uncoupling of cerebral blood flow and metabolism in the brain.

    Science.gov (United States)

    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.

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

    DEFF Research Database (Denmark)

    Trangmar, Steven J; Chiesa, Scott T; Llodio, Iñaki

    2015-01-01

    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...... 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...... 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...

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

    Science.gov (United States)

    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).

  11. Diurnal variation in baseline human regional cerebral blood flow demonstrated by PET

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, D.J.; Mintun, M.A.; Moore, R.Y. [Univ. of Pittsburgh, PA (United States)] [and others

    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.

  12. Regional cerebral blood flow in various pediatric neurological patients using /sup 123/I-IMP SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, Tohru; Naganuma, Yoshihiro; Hongou, Kazuhisa; Murakami, Miyako; Yamatani, Miwa; Okada, Toshio

    1988-03-01

    The recent development of a new radiopharmaceutical /sup 123/I-isopropyl-iodoamphetamine (IMP), which is taken up by the brain from the blood flow, has offered a possibility of constructing scintigraphy maps of regional cerebral blood flow (rCBF) using single photon emission CT. We used this mehtod in various pediatric neurological diseases. Six patients with cerebro-vascular disorders (moya-moya disease 2, infarction 3 and HHE syndrome 1), 6 patients with infectious diseases of CNS (acute encephalitis 4, septic meningitis 1 and SSPE 1) and a miscellaneous group of six patients were studied. The rCBF abnormalities in cerebro-vascular diseases were more extensive and frequent than x-ray CT abnormalities. Repeated studies of IMP-SPECT revealed usefulness for the understanding of changeable hemodynamic pathophysiology and for the judgment of theraptic effectiveness and prognosis. The rCBF decrease in infectious diseases tended to be more diffuse and slight than that in cerebro-vascular diseases. In almost all patients, the area of rCBF decrease coincided with the area of EEG slowing evaluated by EEG topographic analysis. Brain imaging using /sup 123/I-IMP SPECT may reveal functional abnormalities as well as organic lesions. /sup 123/I-IMP SPECT has introduced a new era for the useful application of nuclear medicine to the investigation of pediatric neurological diseases.

  13. Cerebral blood flow and oxygen metabolism in dementia with Lewy bodies

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yoshitomo; Takahashi, Satoshi; Yonezawa, Hisashi [Iwate Medical Univ., Morioka (Japan). School of Medicine

    2000-06-01

    Regional cerebral blood flow (rCBF), oxygen metabolism (rCMRO{sub 2}) and the oxygen extraction fraction (rOEF) were measured using the steady-state {sup 15}O technique and positron emission tomography (PET) in six patients with dementia with Lewy bodies (DLB), and compared with ten patients with Alzheimer disease (AD) and six normal controls. In the AD patients, rCBF and rCMRO{sub 2} were significantly decreased in the frontal, parietal, and temporal cortices compared with controls. In DLB patients, rCBF and rCMRO{sub 2} were decreased in the frontal, parietal, temporal, and occipital cortices compared with controls, and were decreased more diffusely than in AD patients. rCBF and rCMRO{sub 2} were significantly decreased in occipital cortex compared with AD patients. rOEF was significantly increased in the parieto-temporal cortex in AD patients compared with controls. In DLB patients, rOEF was significantly increased not only in the parieto-temporal cortex but also in the occipital and frontal cortices compared with controls, and was significantly increased in the occipital cortex compared with AD patients. The diffuse reduction of cerebral blood flow and oxygen metabolism including the occipital cortex may be related to visual hallucination and other visuospatial deficits frequently seen in DLB patients. The increase in rOEF may be mainly due to the reduction in the vascular bed associated with decreased activity in the vasodilatory cholinergic system. (author)

  14. Cardiorespiratory fitness mediates the effects of aging on cerebral blood flow

    Directory of Open Access Journals (Sweden)

    Benjamin eZimmerman

    2014-04-01

    Full Text Available 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.

  15. Local Control of Blood Flow

    Science.gov (United States)

    Clifford, Philip S.

    2011-01-01

    Organ blood flow is determined by perfusion pressure and vasomotor tone in the resistance vessels of the organ. Local factors that regulate vasomotor tone include myogenic and metabolic autoregulation, flow-mediated and conducted responses, and vasoactive substances released from red blood cells. The relative importance of each of these factors…

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

    Science.gov (United States)

    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 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 .

  17. Cerebrovascular ETB, 5-HT1B, and AT1 receptor upregulation correlates with reduction in regional CBF after subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Ansar, Saema; Vikman, Petter; Nielsen, Marianne;

    2007-01-01

    with the reduction in regional and global cerebral blood flow (CBF) after subarachnoid hemorrhage (SAH). SAH was induced by injecting 250 microl blood into the prechiasmatic cistern in rats. The cerebral arteries were removed 0, 1, 3, 6, 12, 24, and 48 h after the SAH for functional and molecular studies...

  18. Spatial heterogeneity of the relation between resting-state connectivity and blood flow: an important consideration for pharmacological studies

    NARCIS (Netherlands)

    Khalili-Mahani, N.; Osch, M.J.; Rooij, M.D.; Beckmann, C.F.; Buchem, van M.A.; Dahan, A.; Gerven, van J.M.; Robouts, S.A.

    2014-01-01

    Resting state fMRI (RSfMRI) and arterial spin labeling (ASL) provide the field of pharmacological Neuroimaging tool for investigating states of brain activity in terms of functional connectivity or cerebral blood flow (CBF). Functional connectivity reflects the degree of synchrony or correlation of

  19. Regional cerebral blood flow during rest and skilled hand movements by xenon-133 inhalation and emission computerized tomography

    DEFF Research Database (Denmark)

    Lauritzen, M; Henriksen, L; Lassen, N A

    1981-01-01

    Regional cerebral blood flow (CBF) was studied in 16 normal adult volunteers during rest and in 10 the study was repeated during skilled hand movements. A fast-rotating ("dynamic"), single-photon emission computerized tomograph (ECT) with four detector heads was used. Xenon-133 was inhaled over a 1...

  20. Autistic Traits, ADHD Symptoms, Neurological Soft Signs and Regional Cerebral Blood Flow in Adults with Autism Spectrum Disorders

    Science.gov (United States)

    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…

  1. Nitric oxide does not act as a mediator coupling cerebral blood flow to neural activity following somatosensory stimuli in rats

    DEFF Research Database (Denmark)

    Wang, Qian; Kjaer, T; Jørgensen, M B;

    1993-01-01

    The possible role of nitric oxide (NO) on vibrissa-stimulated increase of regional cerebral cerebral blood flow (rCBF) and cerebral metabolic rate of glucose (rCMRglu) was investigated in conscious Wistar rats by using an inhibitor of NO synthase, NG-nitro-L-arginine (NOLAG) at a concentration of...

  2. Blood Flow in the Microcirculation

    Science.gov (United States)

    Secomb, Timothy W.

    2017-01-01

    The microcirculation is an extensive network of microvessels that distributes blood flow throughout living tissues. Reynolds numbers are much less than 1, and the equations of Stokes flow apply. Blood is a suspension of cells with dimensions comparable to microvessel diameters. Highly deformable red blood cells, which transport oxygen, have a volume concentration (hematocrit) of 40–45% in humans. In the narrowest capillaries, these cells move in single file with a surrounding lubricating layer of plasma. In larger vessels, the red blood cells migrate toward the centerline, reducing the resistance to blood flow. Vessel walls are coated with a layer of macromolecules that restricts flow. At diverging bifurcations, hematocrit is not evenly distributed in the downstream vessels. Other particles are driven toward the walls by interactions with red blood cells. These physiologically important phenomena are discussed here from a fluid mechanical perspective.

  3. Regional cerebral blood flow and cognitive deficits in chronic lyme disease.

    Science.gov (United States)

    Fallon, Brian A; Keilp, John; Prohovnik, Isak; Heertum, Ronald Van; Mann, J John

    2003-01-01

    This study examined brain functioning in patients with Lyme encephalopathy. Eleven patients underwent neuropsychological tests and Xenon(133)-regional cerebral blood flow (rCBF) studies, using an external detector system. Each rCBF scan was age- and sex-matched to two archival, normal controls. While few differences were noted on gray-matter flow indices (ISI, fg), Lyme patients demonstrated significant flow reductions in white matter index (k(2)) (p=.004), particularly in the posterior temporal and parietal lobes bilaterally (p=.003). Flow reductions in white matter areas were significantly associated with deficits in memory (r=.66, p=.027) and visuospatial organization (r=.62, p=.041). Results suggest that Lyme encephalopathy may be a disease primarily affecting the cerebral white matter.

  4. The effect of black tea and caffeine on regional cerebral blood flow measured with arterial spin labeling

    Science.gov (United States)

    Vidyasagar, Rishma; Greyling, Arno; Draijer, Richard; Corfield, Douglas R; Parkes, Laura M

    2013-01-01

    Black tea consumption has been shown to improve peripheral vascular function. Its effect on brain vasculature is unknown, though tea contains small amounts of caffeine, a psychoactive substance known to influence cerebral blood flow (CBF). We investigated the effects on CBF due to the intake of tea components in 20 healthy men in a double-blinded, randomized, placebo-controlled study. On separate days, subjects received a single dose of 184 mg caffeine (equivalent to one strong espresso coffee), 2,820 mg black tea solids containing 184 mg caffeine (equivalent to 6 cups of tea), 2,820 mg decaffeinated black tea solids, or placebo. The CBF and cerebrovascular reactivity (CVR) to hypercapnia were measured with arterial spin labeled magnetic resonance imaging (MRI) before and 2 hours after administration. We found a significant global reduction with caffeine (20%) and tea (21%) in gray matter CBF, with no effect of decaffeinated tea, suggesting that only caffeine influences CBF acutely. Voxelwise analysis revealed the effect of caffeine to be regionally specific. None of the interventions had an effect on CVR. Additional research is required to conclude on the physiologic relevance of these findings and the chronic effects of caffeine and tea intake on CBF. PMID:23486295

  5. The effect of black tea and caffeine on regional cerebral blood flow measured with arterial spin labeling.

    Science.gov (United States)

    Vidyasagar, Rishma; Greyling, Arno; Draijer, Richard; Corfield, Douglas R; Parkes, Laura M

    2013-06-01

    Black tea consumption has been shown to improve peripheral vascular function. Its effect on brain vasculature is unknown, though tea contains small amounts of caffeine, a psychoactive substance known to influence cerebral blood flow (CBF). We investigated the effects on CBF due to the intake of tea components in 20 healthy men in a double-blinded, randomized, placebo-controlled study. On separate days, subjects received a single dose of 184 mg caffeine (equivalent to one strong espresso coffee), 2,820 mg black tea solids containing 184 mg caffeine (equivalent to 6 cups of tea), 2,820 mg decaffeinated black tea solids, or placebo. The CBF and cerebrovascular reactivity (CVR) to hypercapnia were measured with arterial spin labeled magnetic resonance imaging (MRI) before and 2 hours after administration. We found a significant global reduction with caffeine (20%) and tea (21%) in gray matter CBF, with no effect of decaffeinated tea, suggesting that only caffeine influences CBF acutely. Voxelwise analysis revealed the effect of caffeine to be regionally specific. None of the interventions had an effect on CVR. Additional research is required to conclude on the physiologic relevance of these findings and the chronic effects of caffeine and tea intake on CBF.

  6. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang; Lou, Yaxian; Pan, Zhiying; Liu, Ya [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Aivil Aviation, Nanjing, Jiangsu (China); Wen, Jiqiu; Li, Xue; Zhang, Zhe [Medical School of Nanjing University, National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing, Jiangsu (China); Lu, Hanzhang [University of Texas Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX (United States); Liu, Wei [Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, Guangdong (China); Liu, Hui [Siemens MR NEA Collaboration, Siemens Ltd., Shanghai (China); Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China)

    2016-06-15

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO{sub 2} was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min{sup -1} 100 g{sup -1}, P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO{sub 2} (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O{sub 2} min{sup -1} 100 g{sup -1}, P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO{sub 2}. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO{sub 2}. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO{sub 2}. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  7. The evaluation of cerebral hemodynamics in patients with intracranial tumors by stable xenon CT; The effect of glycerol administration on regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Shimoda, Masami; Kawamata, Fumio; Yamamoto, Masahiro; Ohsuga, Hitoshi; Hidaka, Mitsuru; Oda, Shinri; Shibuya, Naoki; Yamamoto, Isao; Sato, Osamu (Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine)

    1989-04-01

    In evaluating cerebral regional blood flow (rCBF), stable xenon-enhanced tomography (XeCT) study associated with simultaneous blood sampling was applied in 15 cases of intracranial neoplasms. The effect of intravenous glycerol infusion on rCBF was also investigated. The results indicated that intratumoral rCBF values were not only variable and unrelated to their histological types and grades, but also were not correlated with the vascularity of the lesion as demonstrated by angiography. When a tumor mass was enhanced after the injection of iodinated contrast media, it proved to be useful in distinguishing tumor mass and its associated edema that the rCBF of the peritumoral edematous region was predominantly low (10{plus minus}5 ml/100 g/min). The regional cerebral blood flow in remote areas, both ipsilateral and contralateral to the lesion, was low in value, and there was no statistical significance between affected and sound sides. Following glycerol administration, rCBF was increased in the whole intracranial region, but not inside of the neoplasm, particularly when the intracranial pressure (ICP) was increased. It was assumed that the elevated rCBF after glycerol administration was due to the increase in the cerebral perfusion pressure resulting from the ICP reduction, the hemodilution effect, cerebral vessel dilatation after metabolic acidosis, and/or mechanically rectified microcirculation after edema reduction. (author).

  8. A new method of regional cerebral blood flow measurement using one-point arterial sampling based on the microsphere model with N-isopropyl-p-[[sup 123]I]-iodoamphetamine SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Odano, I.; Takahashi, N.; Higuchi, T. (Niigata Univ. (Japan). School of Medicine); Ohkubo, M. (Niigata Univ. (Japan). Coll. of Biomedical Technology)

    1994-07-01

    We developed a new method for quantitative measurement of regional cerebral blood flow (rCBF) using one-point arterial sampling with N-isopropyl-p-[[sup 123]I]-iodoamphetamine ([sup 123]I-IMP) and single photon emission computed tomography (SPECT) based on the microsphere model. The one-point Ca(t) method provides fast, easy, accurate and non-invasive measurement of rCBF without inserting catheters and without treatment of arterial blood with octanol. (author).

  9. Cluster headache: transcranial Doppler ultrasound and regional cerebral blood flow studies

    Energy Technology Data Exchange (ETDEWEB)

    Dahl, A.; Russell, D.; Nyberg-Hansen, R.; Rootwelt, K. (Rikshospitalet, Oslo (Norway))

    1990-04-01

    Transcranial Doppler and rCBF examinations were carried out in 25 cluster headache patients. Spontaneous glyceryl trinitrate (nitroglycerin) provoked attacks were accompanied by a bilateral decrease in middle cerebral artery blood flow velocities. This decrease was more pronounced on the symptomatic side, but the difference did not reach statistical significance. Mean hemispheric blood flow and rCBF were within normal limits during provoked attacks and similar to those found when patients were attack-free. During cluster periods middle cerebral artery velocities were significantly higher on the symptomatic side. Glyceryl trinitrate caused a bilateral middle cerebral artery velocity decrease which was significantly greater on the symptomatic side. Attacks provoked by glyceryl trinitrate appeared to begin when the vasodilatory effect of this substance was received. 17 refs., 2 figs., 5 tabs.

  10. Left-right cortical asymmetries of regional cerebral blood flow during listening to words

    DEFF Research Database (Denmark)

    Nishizawa, Y; Olsen, T S; Larsen, B;

    1982-01-01

    1. Regional cerebral blood flow (rCBF) was measured during rest and during listening to simple words. The xenon-133 intracarotid technique was used and results were obtained from 254 regions of seven right hemispheres and seven left hemispheres. The measurements were performed just after carotid...... angiography, carried out to exclude space occupying lesions. In all subjects the angiogram was normal. All were right handed. 2. Mean hemispheric blood flow of both left and right hemispheres increased 10% from the resting measurement during the listening task. This increase was due in part to activation...... widespread and intense increase, averaging 29% as compared to 18% on the right side. This left-sided dominance during verbal stimulation should be compared to the right-sided dominance of rCBF during nonverbal sound discrimination reported by Roland et al. (25, 26), who used precisely the same technique...

  11. Focal hyperemia followed by spreading oligemia and impaired activation of rCBF in classic migraine

    DEFF Research Database (Denmark)

    Olesen, J; Larsen, B; Lauritzen, M

    1981-01-01

    Regional cerebral blood flow (rCBF) was measured in 254 areas of a hemisphere with the xenon 133 intraarterial injection method. Six cases of classic migraine were followed from the normal state into the prodromal phase, and in 3 cases further into the headache phase. One patient with common...... anteriorly in the course of 15 to 45 minutes. In 4 patients a global oligemia was observed. In 4 patients severe headache was present concomitantly with oligemia and with no sign of hyperemia or nonhomogeneous brain perfusion. The normal rCBF increase during cortical activity (hand movement, speech...

  12. Endovascular blood flow measurement system

    Science.gov (United States)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  13. Rheoencephalography (REG) as a Non-Invasive Monitoring Alternative for the Assessment of Brain Blood Flow

    Science.gov (United States)

    2004-09-01

    bioimpedance (rheoencephalography - REG) measurement as a non-invasive, continuous method for assessing the status of cerebral blood flow (CBF) in combat...Dunster KR, Colditz PB, Ward LC. Noninvasive measurement of cerebral bioimpedance for detection of cerebral edema in the neonatal piglet. Brain Res...REG measurements and DC impedance (Ro) were recorded simultaneously on a portable IBM compatible computer using CODAS (DATAQ, Inc., Akron, OH) data

  14. Mapping Long-Term Functional Changes in Cerebral Blood Flow by Arterial Spin Labeling

    Science.gov (United States)

    Ssali, Tracy; Anazodo, Udunna C.; Bureau, Yves; MacIntosh, Bradley J.; Günther, Matthias; St. Lawrence, Keith

    2016-01-01

    Although arterial spin labeling (ASL) is appealing for mapping long-term changes in functional activity, inter-sessional variations in basal blood flow, arterial transit times (ATTs), and alignment errors, can result in significant false activation when comparing images from separate sessions. By taking steps to reduce these sources of noise, this study assessed the ability of ASL to detect functional CBF changes between sessions. ASL data were collected in three sessions to image ATT, resting CBF and CBF changes associated with motor activation (7 participants). Activation maps were generated using rest and task images acquired in the same session and from sessions separated by up to a month. Good agreement was found when comparing between-session activation maps to within-session activation maps with only a 16% decrease in precision (within-session: 90 ± 7%) and a 13% decrease in the Dice similarity (within-session: 0.75 ± 0.07) coefficient after a month. In addition, voxel-wise reproducibility (within-session: 4.7 ± 4.5%) and reliability (within-session: 0.89 ± 0.20) of resting grey-matter CBF decreased by less than 18% for the between-session analysis relative to within-session values. ATT variability between sessions (5.0 ± 2.7%) was roughly half the between-subject variability, indicating that its effects on longitudinal CBF were minimal. These results demonstrate that conducting voxel-wise analysis on CBF images acquired on different days is feasible with only modest loss in precision, highlighting the potential of ASL for longitudinal studies. PMID:27706218

  15. Cerebral Blood Flow Dynamics and Head-of-Bed Changes in the Setting of Subarachnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    David K. Kung

    2013-01-01

    Full Text Available Head-of-bed (HOB elevation is usually restricted in patients with aneurysmal subarachnoid hemorrhage (SAH. The goal of this study is to correlate HOB changes ( and with cerebral blood flow using transcranial Doppler (TCD and thermal diffusion probe in SAH patients. Thirteen patients with SAH were prospectively enrolled in the study. Eight patients underwent placement of a thermal diffusion probe for regional CBF measurement. CBF values were measured with the patients in flat ( and upright sitting positions ( at days 3, 7, and 10. The average increase in blood flow velocity when changing HOB from to was 7.8% on day 3, 0.1% on day 7, and 13.1% on day 10. The middle cerebral artery had the least changes in velocity. The average regional CBF measurement was 22.7 ± 0.3 mL/100 g/min in the supine position and 23.6 ± 9.1 mg/100 g/min in the sitting position. The changes were not statistically significant. None of the patients developed clinical cerebral vasospasm. Changing HOB position in the setting of SAH did not significantly affect cerebral or regional blood flow. These data suggest that early mobilization should be considered given the detrimental effects of prolonged bed rest.

  16. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, H. (Den Sundhedsfaglige Kandidatuddannelse, Aarhus Universitet Bygning 1264, Aarhus (Denmark); University College Nordjylland, Aalborg (Denmark)), Email: hnt@ucn.dk; Steffensen, E. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark)); Larsson, E. M. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); Uppsala University Hospital, Department of Radiology, Uppsala (Sweden))

    2012-02-15

    Background. Perfusion magnetic resonance imaging (MRI) is increasingly used in the evaluation of brain tumors. Relative cerebral blood volume (rCBV) is usually obtained by dynamic susceptibility contrast (DSC) MRI using normal appearing white matter as reference region. The emerging perfusion technique arterial spin labelling (ASL) presently provides measurement only of cerebral blood flow (CBF), which has not been widely used in human brain tumor studies. Purpose. To assess if measurement of blood flow is comparable with measurement of blood volume in human biopsy-proven gliomas obtained by DSC-MRI using two different regions for normalization and two different measurement approaches. Material and Methods. Retrospective study of 61 patients with different types of gliomas examined with DSC perfusion MRI. Regions of interest (ROIs) were placed in tumor portions with maximum perfusion on rCBF and rCBV maps, with contralateral normal appearing white matter and cerebellum as reference regions. Larger ROIs were drawn for histogram analyses. The type and grade of the gliomas were obtained by histopathology. Statistical comparison was made between diffuse astrocytomas, anaplastic astrocytomas, and glioblastomas. Results. rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r = 0.60) and to the cerebellum (r = 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated (0.61 < r < 0.93), whereas for kurtosis and peak height, the correlation coefficient was about 0.3 when comparing rCBF and rCBV values for the same reference region. Neither rCBF nor rCBV quantification provided a statistically significant difference between the three types of gliomas. However, both rCBF and rCBV tended to increase with tumor grade and to be lower in patients who had undergone resection/treatment. Conclusion. rCBF measurements normalized to white matter

  17. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen;

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined...... was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE-EPI measured a significant...... increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In conclusion...

  18. SPECT with [99mTc]-d,l-hexamethyl-propylene amine oxime (HM-PAO) compared with regional cerebral blood flow measured by PET

    DEFF Research Database (Denmark)

    Yonekura, Y; Nishizawa, S; Mukai, Thomas Søgaard;

    1988-01-01

    In order to validate the use of technetium-99m-d,l-hexamethylpropyleneamine oxime (HM-PAO) as a flow tracer, a total of 21 cases were studied with single photon emission computerized tomography (SPECT), and compared to regional cerebral blood flow (rCBF) measured by position emission tomography (...

  19. A longitudinal study of cerebral blood flow under hypoxia at high altitude using 3D pseudo-continuous arterial spin labeling

    Science.gov (United States)

    Liu, Wenjia; Liu, Jie; Lou, Xin; Zheng, Dandan; Wu, Bing; Wang, Danny J. J.; Ma, Lin

    2017-01-01

    Changes in cerebral blood flow (CBF) may occur with acute exposure to high altitude; however, the CBF of the brain parenchyma has not been studied to date. In this study, identical magnetic resonance scans using arterial spin labeling (ASL) were performed to study the haemodynamic changes at both sea level and high altitude. We found that with acute exposure to high altitude, the CBF in acute mountain sickness (AMS) subjects was higher (P  0.05) compared with those at sea level. Moreover, magnetic resonance angiography in both AMS and non-AMS subjects showed a significant increase in the cross-sectional areas of the internal carotid, basilar, and middle cerebral arteries on the first day at high altitude. These findings support that AMS may be related to increased CBF rather than vasodilation; these results contradict most previous studies that reported no relationship between CBF changes and the occurrence of AMS. This discrepancy may be attributed to the use of ASL for CBF measurement at both sea level and high altitude in this study, which has substantial advantages over transcranial Doppler for the assessment of CBF. PMID:28240265

  20. Hyperhomocysteinemia decreases bone blood flow

    Directory of Open Access Journals (Sweden)

    Neetu T

    2011-01-01

    Full Text Available Neetu Tyagi*, Thomas P Vacek*, John T Fleming, Jonathan C Vacek, Suresh C TyagiDepartment of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY, USA *These authors have equal authorshipAbstract: Elevated plasma levels of homocysteine (Hcy, known as hyperhomocysteinemia (HHcy, are associated with osteoporosis. A decrease in bone blood flow is a potential cause of compromised bone mechanical properties. Therefore, we hypothesized that HHcy decreases bone blood flow and biomechanical properties. To test this hypothesis, male Sprague–Dawley rats were treated with Hcy (0.67 g/L in drinking water for 8 weeks. Age-matched rats served as controls. At the end of the treatment period, the rats were anesthetized. Blood samples were collected from experimental or control rats. Biochemical turnover markers (body weight, Hcy, vitamin B12, and folate were measured. Systolic blood pressure was measured from the right carotid artery. Tibia blood flow was measured by laser Doppler flow probe. The results indicated that Hcy levels were significantly higher in the Hcy-treated group than in control rats, whereas vitamin B12 levels were lower in the Hcy-treated group compared with control rats. There was no significant difference in folate concentration and blood pressure in Hcy-treated versus control rats. The tibial blood flow index of the control group was significantly higher (0.78 ± 0.09 flow unit compared with the Hcy-treated group (0.51 ± 0.09. The tibial mass was 1.1 ± 0.1 g in the control group and 0.9 ± 0.1 in the Hcy-treated group. The tibia bone density was unchanged in Hcy-treated rats. These results suggest that Hcy causes a reduction in bone blood flow, which contributes to compromised bone biomechanical properties.Keywords: homocysteine, tibia, bone density

  1. Ultrasound modulated light blood flow measurement using intensity autocorrelation function: a Monte-Carlo simulation

    Science.gov (United States)

    Tsalach, A.; Metzger, Y.; Breskin, I.; Zeitak, R.; Shechter, R.

    2014-03-01

    Development of techniques for continuous measurement of regional blood flow, and in particular cerebral blood flow (CBF), is essential for monitoring critical care patients. 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 133 Xe SPECT1 and laser Doppler2. Coherent light is introduced into the tissue concurrently with an Ultrasound (US) field. Displacement of scattering centers within the sampled volume induced by Brownian motion, blood flow and the US field affects the photons' temporal correlation. Hence, the temporal fluctuations of the obtained speckle pattern provide dynamic information about the blood flow. We developed a comprehensive simulation, combining the effects of Brownian motion, US and flow on the obtained speckle pattern. Photons trajectories within the tissue are generated using a Monte-Carlo based model. Then, the temporal changes in the optical path due to displacement of scattering centers are determined, and the corresponding interference pattern over time is derived. Finally, the light intensity autocorrelation function of a single speckle is calculated, from which the tissue decorrelation time is determined. The simulation's results are compared with in-vitro experiments, using a digital correlator, demonstrating decorrelation time prediction within the 95% confidence interval. This model may assist in the development of optical based methods for blood flow measurements and particularly, in methods using the acousto-optic effect.

  2. Coupling of cerebral blood flow and oxygen metabolism is conserved for chromatic and luminance stimuli in human visual cortex.

    Science.gov (United States)

    Leontiev, Oleg; Buracas, Giedrius T; Liang, Christine; Ances, Beau M; Perthen, Joanna E; Shmuel, Amir; Buxton, Richard B

    2013-03-01

    The ratio of the changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) during brain activation is a critical determinant of the magnitude of the blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI). Cytochrome oxidase (CO), a key component of oxidative metabolism in the mitochondria, is non-uniformly distributed in visual area V1 in distinct blob and interblob regions, suggesting significant spatial variation in the capacity for oxygen metabolism. The goal of this study was to test whether CBF/CMRO(2) coupling differed when these subpopulations of neurons were preferentially stimulated, using chromatic and luminance stimuli to preferentially stimulate either the blob or interblob regions. A dual-echo spiral arterial spin labeling (ASL) technique was used to measure CBF and BOLD responses simultaneously in 7 healthy human subjects. When the stimulus contrast levels were adjusted to evoke similar CBF responses (mean 65.4% ± 19.0% and 64.6% ± 19.9%, respectively for chromatic and luminance contrast), the BOLD responses were remarkably similar (1.57% ± 0.39% and 1.59% ± 0.35%) for both types of stimuli. We conclude that CBF-CMRO(2) coupling is conserved for the chromatic and luminance stimuli used, suggesting a consistent coupling for blob and inter-blob neuronal populations despite the difference in CO concentration.

  3. Chaotic advection in blood flow.

    Science.gov (United States)

    Schelin, A B; Károlyi, Gy; de Moura, A P S; Booth, N A; Grebogi, C

    2009-07-01

    In this paper we argue that the effects of irregular chaotic motion of particles transported by blood can play a major role in the development of serious circulatory diseases. Vessel wall irregularities modify the flow field, changing in a nontrivial way the transport and activation of biochemically active particles. We argue that blood particle transport is often chaotic in realistic physiological conditions. We also argue that this chaotic behavior of the flow has crucial consequences for the dynamics of important processes in the blood, such as the activation of platelets which are involved in the thrombus formation.

  4. SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY STUDY OF REGIONAL CEREBRAL BLOOD FLOW IN PATIENTS WITH HEMISPATIAL NEGLECT

    Institute of Scientific and Technical Information of China (English)

    尹雅芙; 任艳; 李亚明

    2003-01-01

    Objective.To explore the correlations between the occurrence and severity of neglect and the region,range or extent of the decrease in regional cerebral blood flow(rCBF). Methods. Nineteen dextromanual patients who were diagnosed as unilateral stroke clinically and hemispatial neglect by a neglect test battery received single photon emission computed tomography(SPECT) scans. Results. On images,the damages of patients with neglect were seen most frequently in the frontal cortex,and then in turn in the parietal cortex,occipital cortex,temporal cortex,basal ganglia and thalamus. Most patients with neglect had two or more regions damaged. The most significant region was temporal-parietal-occipi-tal(TPO)junction. The correlation coefficient between rCBF and the severity of neglect was -0.34(t=-1.5,P>0.05),and that between the decrease percentage of rCBF and the severity of neglect was 0.34(t=1.47,P>0.05). The correlation coefficients between the range,number of foci,the flow deficit size and the severity of neglect were 0.71(t=4.13,P<0.01),0.70(t=4.07,P<0.01)and 0.64(t=3.40, P<0.01),respectively. Conclusions. The severity of neglect correlates with rCBF and the decrease percentage of rCBF insignificantly,but correlates positively with the range,number of foci and the flow deficit size significantly. Hemispatial neglect is caused by the damage of multiple sites and combined damage results in more severe neglect.

  5. Regional cerebral blood flow and the effects of nicardipine, a new cerebral vasodilator, in patients with neuropsychiatric symptoms. A study of /sup 133/Xe inhalation method

    Energy Technology Data Exchange (ETDEWEB)

    Toyoda, Katsuhiro; Motomura, Naoyasu; Murata, Koen; Sakai, Toshiaki (Osaka Medical Coll., Takatsuki (Japan)); Yoshioka, Michio; Tsutsumi, Shigetoshi

    1984-02-01

    Regional cerebral blood flow (rCBF) was determined by /sup 133/Xe inhalation method in 22 neuropsychiatric patients with an average age of 65.8 years -- 14 patients having cerebrovascular disturbance (Group 1) and 8 patients having endogenous or organic psychosis or neurological lesions (Group 2). Furthermore, nicardipine was orally administered to the patients and its effects on rCBF and on neuropsychiatric symptoms were examined. Regarding the mean and abnormal decrease of rCBF in the bilateral hemispheres and the frequency of ischemic foci, there was no significant difference between the groups. However, regional ischemic focus was more frequently observed in Group 1 than in Group 2. Long-term serial administration of nicardipine increased the rCBF and improved psychiatric symptoms in some of the patients in Group 1.

  6. Impaired autoregulation of cerebral blood flow in the distressed newborn infant

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Friis-Hansen, B

    1979-01-01

    Cerebral blood flow was measured, using the 133Xe clearance technique, a few hours after birth in 19 infants with varying degrees of respiratory distress syndrome. Ten of these infants had had asphyxia at birth. The least affected infants with normotension (systolic blood pressure 60 to 65 mm Hg...... at birth and infants with RDS only. CBF varied considerably with spontaneous variations in blood pressure, suggesting that autoregulation was lacking. This finding may explain why distressed premature infants are prone to develop massive capillary bleeding in the germinal layer with penetration...

  7. Magnetohydrodynamics of blood flow.

    Science.gov (United States)

    Keltner, J R; Roos, M S; Brakeman, P R; Budinger, T F

    1990-10-01

    The changes in hydrostatic pressure and electrical potentials across vessels in the human vasculature in the presence of a large static magnetic field are estimated to determine the feasibility of in vivo NMR spectroscopy at fields as high as 10 T.A 10-T magnetic field changes the vascular pressure in a model of the human vasculature by less than 0.2%. An exact solution to the magnetohydrodynamic equations describing a conducting fluid flowing transverse to a static magnetic field in a nonconducting, straight, circular tube is used. This solution is compared to an approximate solution that assumes that no magnetic fields are induced in the fluid and that has led previous investigators to predict significant biological effects from static magnetic fields. Experimental results show that the exact solution accurately predicts the magnetohydrodynamic slowing of 15% NaCl flowing transverse to 2.3- and 4.7-T magnetic fields for fluxes below 0.5 liter/min while the approximate solution predicts a much more retarded flow.

  8. Quantitative assessment of blood flow reserve using {sup 99m}Tc-HMPAO in carotid stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Garai, I.; Varga, J.; Galuska, L. [Department of Nuclear Medicine, University of Debrecen Medical and Health Centre, Debrecen (Hungary); Szomjak, E. [3. Department of Internal Medicine, University of Debrecen Medical and Health Centre, Debrecen (Hungary); Toth, C.; Olvaszto, S. [1. Department of Surgery, University of Debrecen Medical and Health Centre, Debrecen (Hungary); Bank, J. [Department of Neurology, Kenezy Hospital (Hungary); Ficzere, A. [Department of Neurology, University of Debrecen Medical and Health Centre, Debrecen (Hungary)

    2002-02-01

    Dynamic imaging of the inflow of technetium-99m hexamethylpropylene amine oxime (HMPAO) to the brain has been proved to allow estimation of the hemispherical cerebral blood flow (CBF) using the Patlak plot. In this study, we compared the hemispherical CBF (in ml/min/100 g) of different patient groups. A total of 25 patients (comprising 13 with migraine and 12 scheduled for endarterectomy owing to angiographically confirmed severe stenosis of the internal carotid artery on at least one side) underwent baseline and acetazolamide {sup 99m}Tc-HMPAO brain perfusion studies. In addition, acetazolamide {sup 99m}Tc-HMPAO studies were performed in 12 healthy subjects (no baseline study was performed for ethical reasons.) Dynamic studies were acquired by means of a dual-detector gamma camera with a large field of view (HELIX, Elscint). Special difference images were created to make definition of the aortic arch and hemispherical brain regions easier and more reproducible. A semi-automatic method was developed to determine the transit time from the aorta to the brain, making the generation of the Patlak plot even more robust. The baseline CBF values did not significantly depend on the disease (P>0.1), whereas the CBF values obtained after acetazolamide provocation did do so (ANOVA, P<0.001). Patients suffering from migraine showed a significant increase in global CBF values after acetazolamide provocation (paired t test, P<0.05), but we could not find any effect of the provocation in patients awaiting carotid endarterectomy, indicating a lack of cerebrovascular reserve capacity. Comparison of the results of the acetazolamide study in patients and the control group revealed the CBF values to be significantly lower in patients with carotid stenosis (two-sample t-test, P<0.001), but not in those with migraine (P>0.1). In summary, using quantitative analysis of {sup 99m}Tc-HMPAO brain studies we could objectively compare the CBF of patients suffering from different diseases

  9. Laser Doppler flowmetry is valid for measurement of cerebral blood flow autoregulation lower limit in rats

    DEFF Research Database (Denmark)

    Tonnesen, Jan; Pryds, Anders; Larsen, Erik Hviid

    2005-01-01

    Laser Doppler flowmetry (LDF) is a recent technique that is increasingly being used to monitor relative changes in cerebral blood flow whereas the intra-arterial 133xenon injection technique is a well-established method for repeated absolute measurements of cerebral blood flow. The aim of this st...... CO2 challenge. Haemodilution influences the two methods differently causing relative overestimation of blood flow by the laser Doppler technique compared to the 133xenon method....... of this study was to validate LDF for assessment of cerebral autoregulation and CO2 reactivity with the 133xenon injection technique as the gold standard. Simultaneous measurements of cerebral blood flow (CBF) were collected by LDF (CBFLDF) and the 133xenon method (CBFXe) while (1) cerebral autoregulation...... was challenged by controlled systemic haemorrhage, or (2) cerebral blood flow was varied by manipulating the arterial partial pressure of CO2 (Pa,CO2). LDF slightly overestimated CBF under conditions of haemorrhagic shock and haemodilution caused by controlled haemorrhage (paired t test, P

  10. Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

    Science.gov (United States)

    Johnson, Nathan F; Gold, Brian T; Bailey, Alison L; Clasey, Jody L; Hakun, Jonathan G; White, Matthew; Long, Doug E; Powell, David K

    2016-05-01

    A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness.

  11. Simple exercises that significantly increase cerebral blood flow and cerebral oxygenation

    CERN Document Server

    Gersten, Alexander; Raz, Amir; Fried, Robert

    2011-01-01

    We tested the hypothesis that simple exercises may significantly increase cerebral blood flow (CBF) and/or cerebral oxygenation. Eighteen subjects ranging in age from nineteen to thirty nine participated in a four-stage study during which measurements of end tidal CO_2 (EtCO2 - by capnometer) and local brain oxygenation (by near-infrared spectroscopy (NIRS) sensor) were taken. The four stages were 1) baseline, 2) breathing exercises, 3) solving an arithmetic problem, and 4) biofeedback. During the breathing exercises there was a significant increase in EtCO2 indicating a significant increase in global CBF. The increase in global CBF was estimated on the basis of a theoretical model. During the arithmetic and biofeedback tasks there was a significant increase in the local (Fp1) oxygenation, but it varied between the different participants. The results may lead to new clinical applications of CBF and brain oxygenation monitoring and behavioral control. We foresee future more detailed investigations in the contr...

  12. Sickle Cell Anemia: Reference Values of Cerebral Blood Flow Determined by Continuous Arterial Spin Labeling MRI

    Science.gov (United States)

    Arkuszewski, M.; Krejza, J.; Chen, R.; Melhem, E.R.

    2013-01-01

    Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of “normal” steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3–14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography. PMID:23859242

  13. Sickle cell anemia: reference values of cerebral blood flow determined by continuous arterial spin labeling MRI.

    Science.gov (United States)

    Arkuszewski, M; Krejza, J; Chen, R; Melhem, E R

    2013-04-01

    Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of "normal" steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3-14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography.

  14. The Utility of Cerebral Blood Flow as a Biomarker of Preclinical Alzheimer’s Disease

    Science.gov (United States)

    Hays, Chelsea C.; Zlatar, Zvinka Z.; Wierenga, Christina E.

    2017-01-01

    There is accumulating evidence suggesting that changes in brain perfusion are present long before the clinical symptoms of Alzheimer’s disease (AD), perhaps even before amyloid-β accumulation or brain atrophy. This evidence, consistent with the vascular hypothesis of AD, implicates cerebral blood flow (CBF) in the pathogenesis of AD and suggests its utility as a biomarker of preclinical AD. The extended preclinical phase of AD holds particular significance for disease-modification, as treatment would likely be most effective in this early asymptomatic stage of disease. This highlights the importance of identifying reliable and accurate biomarkers of AD that can differentiate normal aging from preclinical AD prior to clinical symptom manifestation. Cerebral perfusion, as measured by arterial spin labeling magnetic resonance imaging (ASL-MRI), has been shown to distinguish between normal controls and adults with AD. In addition to demonstrating diagnostic utility, CBF has shown usefulness as a tool for identifying those who are at risk for AD and for predicting subtle cognitive decline and conversion to mild cognitive impairment (MCI) and AD. Taken together, this evidence not only implicates CBF as a useful biomarker for tracking disease severity and progression, but also suggests that ASL-measured CBF may be useful for identifying candidates for future AD treatment trials, especially in the preclinical, asymptomatic phases of the disease. PMID:26898552

  15. Correlations of cerebral blood flow with language function in aphasic patients following cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Eriko; Nagata, Ken; Uemura, Kazuo [Research Inst. for Brain and Blood Vessels, Akita (Japan)

    1997-04-01

    To elucidate the participation of the brain regions in language function, cerebral blood flow (CBF) which were measured with positron emission tomography (PET) were compared with the language scores based on the standard language test for aphasics in 97 right-handed patients with aphasia due to cerebral infarction. PET studies were performed on 71.4{+-}107.3 days after onset. By the linear regression analysis, the aphasic scores were correlated with the regional CBF from 55 brain regions. CBF from the left frontal, left temporal, and left parietal lobes significantly correlated with language scores of auditory comprehension, speaking, reading, writing, calculation, and repetition. Highly significant correlation was obtained from the left posterior inferior frontal, superior temporal, supramarginal and angular gyri. CBF from the right inferior frontal, right superior temporal, right parahippocampal and right anterior cingulate gyri also correlated with the auditory comprehension, speaking and reading. Accordingly, in addition to the classical language areas which play an essential roles in language function, the extensive areas in the left hemisphere and some part of the right hemisphere may be related to the language processing and recovery from aphasia. (author)

  16. Correlation between cerebral oxygen metabolism and cerebral blood flow simultaneously measured before and after acetazolamide administration

    Science.gov (United States)

    Yamaguchi, Hiroichiro; Yamauchi, Hideto; Hazama, Shiro; Hamamoto, Hirotsugu; Inoue, Nobuhiro

    1999-10-01

    The cerebral circulation and metabolism of ten preoperative cardiac surgery patients were assessed. Alterations in regional cerebral blood flow (rCBF), measured by 123I-N- isopropyl-p-iodo-amphetamine single-photon emission computed tomography, and in cerebral oxygen metabolism, simultaneously detected by near-infrared spectroscopy (NIRS) before and after acetazolamide administration, were investigated. The rCBF (ml/min/100 g) increased significantly from 40.21 +/- 7.65 to 56.24 +/- 13.69 (p equals 0.001), and a significant increase in oxyhemoglobin (Oxy-Hb) of 13.9% (p equals 0.0022) and total hemoglobin (Total-Hb) of 5.7% (0.0047) along with a significant decrease in deoxyhemoglobin (Deoxy-Hb) of 8.9% (p equals 0.0414) were observed concomitantly. Thus, the Oxy-Hb/Total- Hb ratio (%Oxy-Hb) rose significantly from 67.26 +/- 9.82% to 72.98 +/- 8.09% (p equals 0.0022). Examination of the relationships between individual parameters showed that the percentage changes in rCBF and Oxy-Hb were significantly correlated (r equals 0.758, p equals 0.011). The percentage changes in rCBF and %Oxy-Hb were also correlated significantly (r equals 0.740, p equals 0.014). In conclusion, this evidence suggested that NIRS is able to detect relative changes in cerebral hemodynamics and reflect luxury perfusion induced by acetazolamide.

  17. Sympathetic influence on cerebral blood flow and metabolism during exercise in humans

    DEFF Research Database (Denmark)

    Seifert, Thomas; Secher, Niels H

    2011-01-01

    , but not by beta1-adrenergic blockade. Furthermore, endurance training appears to lower the cerebral non-oxidative carbohydrate uptake and preserve cerebral oxygenation during submaximal exercise. This is possibly related to an attenuated catecholamine response. Finally, exercise promotes brain health as evidenced......This review focuses on the possibility that autonomic activity influences cerebral blood flow (CBF) and metabolism during exercise in humans. Apart from cerebral autoregulation, the arterial carbon dioxide tension, and neuronal activation, it may be that the autonomic nervous system influences CBF...... as evidenced by pharmacological manipulation of adrenergic and cholinergic receptors. Cholinergic blockade by glycopyrrolate blocks the exercise-induced increase in the transcranial Doppler determined mean flow velocity (MCA Vmean). Conversely, alpha-adrenergic activation increases that expression of cerebral...

  18. Fibro-vascular coupling in the control of cochlear blood flow.

    Directory of Open Access Journals (Sweden)

    Min Dai

    Full Text Available BACKGROUND: Transduction of sound in the cochlea is metabolically demanding. The lateral wall and hair cells are critically vulnerable to hypoxia, especially at high sound levels, and tight control over cochlear blood flow (CBF is a physiological necessity. Yet despite the importance of CBF for hearing, consensus on what mechanisms are involved has not been obtained. METHODOLOGY/PRINCIPAL FINDINGS: We report on a local control mechanism for regulating inner ear blood flow involving fibrocyte signaling. Fibrocytes in the super-strial region are spatially distributed near pre-capillaries of the spiral ligament of the albino guinea pig cochlear lateral wall, as demonstrably shown in transmission electron microscope and confocal images. Immunohistochemical techniques reveal the inter-connected fibrocytes to be positive for Na+/K+ ATPase β1 and S100. The connected fibrocytes display more Ca(2+ signaling than other cells in the cochlear lateral wall as indicated by fluorescence of a Ca(2+ sensor, fluo-4. Elevation of Ca(2+ in fibrocytes, induced by photolytic uncaging of the divalent ion chelator o-nitrophenyl EGTA, results in propagation of a Ca(2+ signal to neighboring vascular cells and vasodilation in capillaries. Of more physiological significance, fibrocyte to vascular cell coupled signaling was found to mediate the sound stimulated increase in cochlear blood flow (CBF. Cyclooxygenase-1 (COX-1 was required for capillary dilation. CONCLUSIONS/SIGNIFICANCE: The findings provide the first evidence that signaling between fibrocytes and vascular cells modulates CBF and is a key mechanism for meeting the cellular metabolic demand of increased sound activity.

  19. Multi-modal analysis of functional connectivity and cerebral blood flow reveals shared and unique effects of propofol in large-scale brain networks.

    Science.gov (United States)

    Qiu, Maolin; Scheinost, Dustin; Ramani, Ramachandran; Constable, R Todd

    2017-03-01

    Anesthesia-induced changes in functional connectivity and cerebral blow flow (CBF) in large-scale brain networks have emerged as key markers of reduced consciousness. However, studies of functional connectivity disagree on which large-scale networks are altered or preserved during anesthesia, making it difficult to find a consensus amount studies. Additionally, pharmacological alterations in CBF could amplify or occlude changes in connectivity due to the shared variance between CBF and connectivity. Here, we used data-driven connectivity methods and multi-modal imaging to investigate shared and unique neural correlates of reduced consciousness for connectivity in large-scale brain networks. Rs-fMRI and CBF data were collected from the same subjects during an awake and deep sedation condition induced by propofol. We measured whole-brain connectivity using the intrinsic connectivity distribution (ICD), a method not reliant on pre-defined seed regions, networks of interest, or connectivity thresholds. The shared and unique variance between connectivity and CBF were investigated. Finally, to account for shared variance, we present a novel extension to ICD that incorporates cerebral blood flow (CBF) as a scaling factor in the calculation of global connectivity, labeled CBF-adjusted ICD). We observed altered connectivity in multiple large-scale brain networks including the default mode (DMN), salience, visual, and motor networks and reduced CBF in the DMN, frontoparietal network, and thalamus. Regional connectivity and CBF were significantly correlated during both the awake and propofol condition. Nevertheless changes in connectivity and CBF between the awake and deep sedation condition were only significantly correlated in a subsystem of the DMN, suggesting that, while there is significant shared variance between the modalities, changes due to propofol are relatively unique. Similar, but less significant, results were observed in the CBF-adjusted ICD analysis, providing

  20. Cerebral blood flow and oxygen metabolism in the Rett syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Hideto; Fueki, Noboru; Suzuki, Hisaharu; Sakuragawa, Norio; Iio, Masaaki (National Central Hospital for Mental, Nervous and Muscular Disorders, Tokyo (Japan))

    1992-05-01

    Positron emission tomography (PET) was performed on six patients with the Rett syndrome and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO{sub 2}) was low in five patients, and oxygen extraction fraction (OEF) was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in the Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both the cerebral blood flow (CBF) and CMRO{sub 2} were lower than those for the controls, which may indicate the loss of of hyperfrontality in the Rett syndrome. Distribution of brain metabolism may be immature in the Rett syndrome. (author).

  1. A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood

    OpenAIRE

    2015-01-01

    Rationale -Evidence suggests interactive effects of the tea components caffeine and L-theanine on behaviour, yet no data exists exploring the impact of the two on cerebral blood flow (CBF).\\ud \\ud Objectives - The current placebo-controlled, double-blind, counterbalanced, crossover study examined the effects of caffeine and L-theanine on CBF and extended previous cognitive and mood findings by using lower doses than previous studies of a similar methodology, which more closely reflect the rat...

  2. Direct comparison of local cerebral blood flow rates measured by MRI arterial spin-tagging and quantitative autoradiography in a rat model of experimental cerebral ischemia.

    Science.gov (United States)

    Ewing, James R; Wei, Ling; Knight, Robert A; Pawa, Swati; Nagaraja, Tavarekere N; Brusca, Thomas; Divine, George W; Fenstermacher, Joseph D

    2003-02-01

    The present study determined cerebral blood flow (CBF) in the rat using two different magnetic resonance imaging (MRI) arterial spin-tagging (AST) methods and 14C-iodoantipyrine (IAP)-quantitative autoradiography (QAR), a standard but terminal technique used for imaging and quantitating CBF, and compared the resulting data sets to assess the precision and accuracy of the different techniques. Two hours after cerebral ischemia was produced in eight rats via permanent occlusion of one middle cerebral artery (MCA) with an intraluminal suture, MRI-CBF was measured over a 2.0-mm coronal slice using single-coil AST, and tissue magnetization was assessed by either a spin-echo (SE) or a variable tip-angle gradient-echo (VTA-GE) readout. Subsequently ( approximately 2.5 hours after MCA occlusion), CBF was assayed by QAR with the blood flow indicator 14C-IAP, which produced coronal images of local flow rates every 0.4 mm along the rostral-caudal axis. The IAP-QAR images that spanned the 2-mm MRI slice were selected, and regional flow rates (i.e., local CBF [lCBF]) were measured and averaged across this set of images by both the traditional approach, which involved reader interaction and avoidance of sectioning artifacts, and a whole film-scanning technique, which approximated total radioactivity in the entire MRI slice with minimal user bias. After alignment and coregistration, the concordance of the CBF rates generated by the two QAR approaches and the two AST methods was examined for nine regions of interest in each hemisphere. The QAR-lCBF rates were higher with the traditional method of assaying tissue radioactivity than with the MRI-analog approach; although the two sets of rates were highly correlated, the scatter was broad. The flow rates obtained with the whole film-scanning technique were chosen for subsequent comparisons to MRI-CBF results because of the similarity in tissue "sampling" among these three methods. As predicted by previous modeling, "true" flow rates

  3. Cerebral Blood Flow Changes after Shunt in Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage: Analysis by statistical Parametric Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, I. Y.; Choi, W. S.; Pak, H. S. [College of Medicine, Univ. of Inhwa, Incheon (Korea, Republic of)

    2003-07-01

    The purpose of this study was to evaluate the changes of regional cerebral blood flow (rCBF) after shunt operation in patients with hydrocephalus after aneurysmal subarachnoid hemorrhage ba statistical parametric mapping (SPM). Seven patients (4 male, mean age 54 years) with hydrocephalus after aneurysmal subarachnoid hemorrhage underwent a shunt operation. Tc-99m HMPAO SPECT was performed within I week before, and 2 weeks after the shunt operation. All of the SPECT images were spatially transformed to standard space, smoothed, and globally normalized. After spatial and count normalization, rCBF of pre- and post- shunting Tc- 99m HMPAO SPECT was estimated at every voxel using t statistics. The voxels with a P value of less than 0.001 were considered to be significantly different. The shunt operation was effective in all patients. Pre-shunting Tc-99m HMPAO SPECT showed hypoperfusion, predominantly in the periventricular area. After shunt operation, periventricular low perfusion was disappeared. The results of this study show that periventricular CBF is impaired in hydrocephalus after aneurysmal subarachnoid hemorrhage. Significant increase of periventricular CBF after shunt operation suggests the evaluation of periventricular CBF by SPM might be of value for the prediction of shunt effectiveness in hydrocephalus.

  4. Intracranial blood flow measured with single photon emission computer tomography (SPECT) during transient -6 degrees head-down tilt.

    Science.gov (United States)

    Satake, H; Konishi, T; Kawashima, T; Matsunami, K; Uno, T; Imai, S; Yamada, H; Hirakawa, C

    1994-02-01

    Regional cerebral blood flow (CBF) during a transient head-down tilt of -6 degrees (-6 degrees HDT) was measured with single photon emission computer tomography (SPECT). CBF was measured and averaged for both sides of the brain areas; e.g., the bilateral anterior cerebral artery (bACA) area, the middle cerebral artery (bMCA) area, the posterior cerebral artery (bPCA) area, bilateral basal ganglia, and the cerebellum. Among these areas, a significant increase in CBF was observed in the basal ganglia and the cerebellum during -6 degrees HDT compared to pre-HDT. When CBF was measured separately in the left or right brain area, these significances disappeared, although a trend of increase or decrease was still observable. A trend of increase was observed in the left anterior cerebral artery (IACA) area, the right middle cerebral artery (rMCA) area, the right posterior cerebral artery (rPCA) area, the left and right basal ganglia, and the cerebellum. In rACA, IMCA and IPCA areas, a slight decrease in CBF was observed. At the same time, cardiac parameters were measured. Heart rate (HR), stroke volume (SV) and cardiac output (CO) did not change significantly, although SV slightly increased and HR slightly decreased during -6 degrees HDT.

  5. Changes in cerebral blood flow and anxiety associated with an 8-week mindfulness programme in women with breast cancer.

    Science.gov (United States)

    Monti, Daniel A; Kash, Kathryn M; Kunkel, Elisabeth J S; Brainard, George; Wintering, Nancy; Moss, Aleezé S; Rao, Hengyi; Zhu, Senhua; Newberg, Andrew B

    2012-12-01

    This study employed functional magnetic resonance imaging to evaluate changes in cerebral blood flow (CBF) associated with the Mindfulness-based Art Therapy (MBAT) programme and correlate such changes to stress and anxiety in women with breast cancer. Eighteen breast cancer patients were randomized to the MBAT or education control group. The patients received the diagnosis of breast cancer between 6 months and 3 years prior to enrollment and were not in active treatment. The age of participants ranged from 52 to 77 years. A voxel-based analysis was performed to assess differences at rest, during meditation and during a stress task. The anxiety sub-scale of the Symptoms Checklist-90-Revised was compared with changes in resting CBF before and after the programmes. Subjects in the MBAT arm demonstrated significant increases in CBF at rest and during meditation in multiple limbic regions, including the left insula, right amygdala, right hippocampus and bilateral caudate. Patients in the MBAT programme also had a significant correlation between increased CBF in the left caudate and decreased anxiety scores. In the MBAT group, responses to a stressful cue resulted in reduced activation of the posterior cingulate. The results demonstrate that the MBAT programme was associated with significant changes in CBF, which correlated with decreased anxiety over an 8-week period.

  6. Positron emission tomography in cerebrovascular disease: The relationship between regional cerebral blood flow, blood volume and oxygen metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Herold, S.

    1985-03-01

    Positron emission tomography in cerebrovascular disease has demonstrated the importance of the relationship between regional cerebral blood flow and the cerebral metabolic activity. In acute stroke it has been found that within the first hours after the onset of symptoms cerebral blood flow in the affected area is more depressed than cerebral oxygen utilisation. This relative preservation of oxygen utilisation results from an increase in the oxygen extraction ratio far above its normal value. However, the oxygen extraction fraction subsequently falls in the following days indicating the transition from a situation of possibly reversible ischaemia to irreversible infarction. In patients with carotid occlusive disease an increase in the oxygen extraction ratio has been observed only in very few cases. It has been shown, however, that at an earlier stage the relationship between CBF and CBV (as CBF/CBV-ratio) provides a sensitive measure of diminished perfusion pressure which could be helpful for the selection of patients for EC-IC bypass surgery. In patients with sickle cell anaemia it has been found that oxygen delivery to the brain is maintained by an increase in cerebral blood flow, whereas the oxygen extraction ratio is not increased despite the presence of a low oxygen affinity haemoglobin. Preliminary observations in classical migraine suggest an ischaemic situation during the attack.

  7. Regional cerebral blood flow and vasoreactivity to acetazolamide in childhood moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Satoshi; Hohkin, Kiyohiro; Kamiyama, Hiroyasu; Abe, Hiroshi [Hokkaido Univ., Sapporo (Japan). School of Medicine; Mitsumori, Kenji

    1995-04-01

    Using the 133-xenon inhalation method and single photon emission CT (SPECT), we measured regional cerebral blood flow (rCBF) and its reactivity to acetazolamide in 15 children with moyamoya disease (spontaneous occlusion of circle of Willis). In most of them, the mean hemispheric cerebral blood flow (mCBF) was similar to that of age-matched healthy children. However, their rCBF distribution was abnormal with low perfusion in the frontal and temporal lobes, and disturbed reactivity to acetazolamide in the frontal, temporal, and parietal lobes. After surgical revascularization of the anterior circulation with STA-MCA anastomosis and encephalo-duro-myo-anterio-sysnangiosis (EDAMS) these abnormal hemodynamics improved dramatically in the anterior circulation, including the frontal lobe. Postoperative SPECT studies revealed that cerebral vasodilatory capacity also improved in the occipital lobe and the basal ganglia. These results suggest that surgical revascularization of the anterior circulation should be carried out in order to improve cerebral hemodynamics as much as possible, especially in the frontal lobe, and it could also improve cerebral perfusion reserve in the posterior circulation. (author).

  8. Absolute Cerebral Blood Flow Infarction Threshold for 3-Hour Ischemia Time Determined with CT Perfusion and 18F-FFMZ-PET Imaging in a Porcine Model of Cerebral Ischemia.

    Science.gov (United States)

    Wright, Eric A; d'Esterre, Christopher D; Morrison, Laura B; Cockburn, Neil; Kovacs, Michael; Lee, Ting-Yim

    2016-01-01

    CT Perfusion (CTP) derived cerebral blood flow (CBF) thresholds have been proposed as the optimal parameter for distinguishing the infarct core prior to reperfusion. Previous threshold-derivation studies have been limited by uncertainties introduced by infarct expansion between the acute phase of stroke and follow-up imaging, or DWI lesion reversibility. In this study a model is proposed for determining infarction CBF thresholds at 3hr ischemia time by comparing contemporaneously acquired CTP derived CBF maps to 18F-FFMZ-PET imaging, with the objective of deriving a CBF threshold for infarction after 3 hours of ischemia. Endothelin-1 (ET-1) was injected into the brain of Duroc-Cross pigs (n = 11) through a burr hole in the skull. CTP images were acquired 10 and 30 minutes post ET-1 injection and then every 30 minutes for 150 minutes. 370 MBq of 18F-FFMZ was injected ~120 minutes post ET-1 injection and PET images were acquired for 25 minutes starting ~155-180 minutes post ET-1 injection. CBF maps from each CTP acquisition were co-registered and converted into a median CBF map. The median CBF map was co-registered to blood volume maps for vessel exclusion, an average CT image for grey/white matter segmentation, and 18F-FFMZ-PET images for infarct delineation. Logistic regression and ROC analysis were performed on infarcted and non-infarcted pixel CBF values for each animal that developed infarct. Six of the eleven animals developed infarction. The mean CBF value corresponding to the optimal operating point of the ROC curves for the 6 animals was 12.6 ± 2.8 mL·min-1·100g-1 for infarction after 3 hours of ischemia. The porcine ET-1 model of cerebral ischemia is easier to implement then other large animal models of stroke, and performs similarly as long as CBF is monitored using CTP to prevent reperfusion.

  9. Absolute Cerebral Blood Flow Infarction Threshold for 3-Hour Ischemia Time Determined with CT Perfusion and 18F-FFMZ-PET Imaging in a Porcine Model of Cerebral Ischemia.

    Directory of Open Access Journals (Sweden)

    Eric A Wright

    Full Text Available CT Perfusion (CTP derived cerebral blood flow (CBF thresholds have been proposed as the optimal parameter for distinguishing the infarct core prior to reperfusion. Previous threshold-derivation studies have been limited by uncertainties introduced by infarct expansion between the acute phase of stroke and follow-up imaging, or DWI lesion reversibility. In this study a model is proposed for determining infarction CBF thresholds at 3hr ischemia time by comparing contemporaneously acquired CTP derived CBF maps to 18F-FFMZ-PET imaging, with the objective of deriving a CBF threshold for infarction after 3 hours of ischemia. Endothelin-1 (ET-1 was injected into the brain of Duroc-Cross pigs (n = 11 through a burr hole in the skull. CTP images were acquired 10 and 30 minutes post ET-1 injection and then every 30 minutes for 150 minutes. 370 MBq of 18F-FFMZ was injected ~120 minutes post ET-1 injection and PET images were acquired for 25 minutes starting ~155-180 minutes post ET-1 injection. CBF maps from each CTP acquisition were co-registered and converted into a median CBF map. The median CBF map was co-registered to blood volume maps for vessel exclusion, an average CT image for grey/white matter segmentation, and 18F-FFMZ-PET images for infarct delineation. Logistic regression and ROC analysis were performed on infarcted and non-infarcted pixel CBF values for each animal that developed infarct. Six of the eleven animals developed infarction. The mean CBF value corresponding to the optimal operating point of the ROC curves for the 6 animals was 12.6 ± 2.8 mL·min-1·100g-1 for infarction after 3 hours of ischemia. The porcine ET-1 model of cerebral ischemia is easier to implement then other large animal models of stroke, and performs similarly as long as CBF is monitored using CTP to prevent reperfusion.

  10. Effects of striatal nitric oxide production on regional cerebral blood flow and seizure development in rats exposed to extreme hyperoxia.

    Science.gov (United States)

    Gasier, Heath G; Demchenko, Ivan T; Allen, Barry W; Piantadosi, Claude A

    2015-12-01

    The endogenous vasodilator and signaling molecule nitric oxide has been implicated in cerebral hyperemia, sympathoexcitation, and seizures induced by hyperbaric oxygen (HBO2) at or above 3 atmospheres absolute (ATA). It is unknown whether these events in the onset of central nervous system oxygen toxicity originate within specific brain structures and whether blood flow is diverted to the brain from peripheral organs with high basal flow, such as the kidney. To explore these questions, total and regional cerebral blood flow (CBF) were measured in brain structures of the central autonomic network in anesthetized rats in HBO2 at 6 ATA. Electroencephalogram (EEG) recordings, cardiovascular hemodynamics, and renal blood flow (RBF) were also monitored. As expected, mean arterial blood pressure and total and regional CBF increased preceding EEG spikes while RBF was unaltered. Of the brain structures examined, the earliest rise in CBF occurred in the striatum, suggesting increased neuronal activation. Continuous unilateral or bilateral striatal infusion of the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester attenuated CBF responses in that structure, but global EEG discharges persisted and did not differ from controls. Our novel findings indicate that: 1) cerebral hyperemia in extreme HBO2 in rats does not occur at the expense of renal perfusion, highlighting the remarkable autoregulatory capability of the kidney, and 2) in spite of a sentinel increase in striatal blood flow, additional brain structure(s) likely govern the pathogenesis of HBO2-induced seizures because EEG discharge latency was unchanged by local blockade of striatal nitric oxide production and concomitant hyperemia.

  11. Can the detection of misery perfusion in chronic cerebrovascular disease be based on reductions in baseline CBF and vasoreactivity?

    Energy Technology Data Exchange (ETDEWEB)

    Okazawa, Hidehiko; Kobayashi, Masato; Pagani, Marco; Yonekura, Yoshiharu [University of Fukui, Biomedical Imaging Research Center, Matcuoka-cho, Fukui (Japan); Tsuchida, Tatsuro [Faculty of Medical Sciences, University of Fukui, Department of Radiology, Fukui (Japan); Arai, Yoshikazu; Isozaki, Makoto [University of Fukui, Department of Neurosurgery, Faculty of Medical Sciences, Fukui (Japan)

    2007-01-15

    The aim of this study was to clarify whether decreases in baseline regional cerebral blood flow (rCBF) and in residual cerebral vasoreactivity (CVR), assessed by the acetazolamide (ACZ) challenge, can detect misery perfusion in patients with chronic cerebrovascular disease (CVD). Oxygen extraction fraction (OEF) and other haemodynamic parameters were measured in 115 patients (64{+-}9 years old) with unilateral cerebrovascular steno-occlusive disease (>70% stenosis) using {sup 15}O-gas and water PET. A significant elevation of OEF, by greater than the mean+2SD compared with healthy controls, was defined as misery perfusion. CBF, CVR determined by percent change in CBF after ACZ administration, OEF and other haemodynamic parameters in the territories of the bilateral middle cerebral arteries were analysed. Diagnostic accuracy for the detection of misery perfusion using the criteria determined by baseline CBF and CVR was evaluated in all patients and in only those patients with occlusive lesions. Ten of 24 patients with misery perfusion showed a significant reduction in CVR. Using criteria determined by significant decreases in CVR and baseline CBF, misery perfusion was detected with a sensitivity of 42% and a specificity of 95% in all patients. In patients with occlusive lesions (n=50), sensitivity was higher but specificity was slightly lower. The diagnostic accuracy of the threshold determined by baseline CBF alone was similar in all patients and in only those patients with occlusive lesions, and was higher than that achieved using the asymmetry index of OEF. Reductions in CVR and baseline CBF in the ACZ challenge for CVD would detect misery perfusion with high specificity. Reduction in baseline rCBF is more accurate than reduction in CVR alone for the detection of misery perfusion. (orig.)

  12. The correlation of the thalamic lesions on MRI with cerebral cortical blood flow in patients with lacunar infarction

    Energy Technology Data Exchange (ETDEWEB)

    Nabatame, Hidehiko; Nakamura, Kazuo; Matsuda, Minoru; Fujimoto, Naoki [Shiga Medical Center, Moriyama (Japan); Fukuyama, Hidenao

    1995-07-01

    We performed MRI and measured cerebral blood flow (CBF) using {sup 123}I-IMP SPECT microsphere model in twenty three right-handed patients with lacunar infarction. Twelve of 23 patients showed chronic deterioration of dysarthria and gait disturbance. The mental function of the patients was evaluated by the Mini-Mental State (MMS) examination. The area of high intensity on T2-weighted images was quantitatively analyzed in the cerebral white matter (WM), lenticular nucleus (LN) and thalamus (THA). The score of MMS was positively correlated with the local CBF in the bilateral frontal, parietal, temporal and occipital cortices (p<0.05). Also, the area of high intensity in the left THA showed a significant negative correlation with local CBF of the bilateral frontal, parietal, temporal and occipital cortices (p<0.001). The high intensity areas of the bilateral LN, right WM and right THA had a significant but weaker negative correlation with local CBF of some cortices. These findings suggest that thalamic lesions on the dominant side play an important role in the reduction of cortical blood flow and the deterioration of mental functions in patients with lacunar infarction. (author).

  13. Subanesthetic concentration of sevoflurane increases regional cerebral blood flow more, but regional cerebral blood volume less, than subanesthetic concentration of isoflurane in human volunteers.

    Science.gov (United States)

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

    2001-10-01

    Both sevoflurane and isoflurane are used in moderate concentrations in neuroanesthesia practice. The limiting factors for using higher concentrations of inhalational anesthetics in patients undergoing neurosurgery are the agents' effects on cerebral blood flow (CBF) and cerebral blood volume (CBV). In particular, an increase in CBV, which is a key determinant of intracranial pressure, may add to the neurosurgical patient's perioperative risk. To compare the effects of a subanesthetic concentration (0.4 minimum alveolar concentration) of sevoflurane or isoflurane on regional CBF (rCBF), regional CBV (rCBV) and regional mean transit time (rMTT), contrast-enhanced magnetic resonance imaging perfusion measurements were made in spontaneously breathing human volunteers. Absolute changes in rCBF, regional CBV, and rMTT during administration of either drug in regions of interest outlined bilaterally in white and grey matter were nonparametrically (Mann-Whitney test) analyzed. Sevoflurane increased rCBF in practically all regions (absolute change, 4.44 +/- 2.87 to 61.54 +/- 2.39 mL/100g per minute) more than isoflurane did (absolute change, 12.91 +/- 2.52 to 52.67 +/- 3.32 mL/100g per minute), which decreased frontal, parietal, and white matter rCBF (absolute change, -1.12 +/- 0.59 to -14.69 +/- 3.03 mL/100g per minute). Regional CBV was higher in most regions during isoflurane administration (absolute change, 0.75 +/- 0.03 to 4.92 +/- 0.16 mL/100g) than during sevoflurane administration (absolute change, 0.05 +/- 0.14 to 3.57 +/- 0.14 mL/100g). Regional mean transit time was decreased by sevoflurane (absolute change, -0.18 +/- 0.05 to -0.60 +/- 0.04 s) but increased by isoflurane (absolute change, 0.19 +/- 0.03 to 0.69 +/- 0.04 s). In summary, regional CBV was significantly lower during sevoflurane than during isoflurane administration, although sevoflurane increased rCBF more than isoflurane, which even decreased rCBF in some regions. For sevoflurane and, even more

  14. Regional cerebral blood flow and cognitive function in patients with obsessive-compulsive disorder

    Directory of Open Access Journals (Sweden)

    Huirong Guo

    2014-01-01

    Full Text Available Objective: To explore the relationship between regional cerebral blood flow (CBF and cognitive function in obsessive-compulsive disorder (OCD. Method: Single-photon emission computed tomography (SPECT was performed for 139 OCD patients and 139 controls, and the radioactivity rate (RAR was calculated. Cognitive function was assessed by the Wisconsin Card Sorting Test (WCST. Results: The RARs of the prefrontal, anterior temporal, and right occipital lobes were higher in patients than controls. For the WCST, correct and classification numbers were significantly lower, and errors and persistent errors were significantly higher in OCD patients. Right prefrontal lobe RAR was negatively correlated with correct numbers, right anterior temporal lobe RAR was positively correlated with errors, and the RARs of the right prefrontal lobe and left thalamus were positively correlated with persistent errors. Conclusion: OCD patients showed higher CBF in the prefrontal and anterior temporal lobes, suggesting that these areas may be related with cognitive impairment.

  15. Effects of hyperthermia on cerebral blood flow and metabolism during prolonged exercise in humans

    DEFF Research Database (Denmark)

    Nybo, Lars; Møller, Kirsten; Volianitis, Stefanos

    2002-01-01

    The development of hyperthermia during prolonged exercise in humans is associated with various changes in the brain, but it is not known whether the cerebral metabolism or the global cerebral blood flow (gCBF) is affected. Eight endurance-trained subjects completed two exercise bouts on a cycle...... ergometer. The gCBF and cerebral metabolic rates of oxygen, glucose, and lactate were determined with the Kety-Schmidt technique after 15 min of exercise when core temperature was similar across trials, and at the end of exercise, either when subjects remained normothermic (core temperature = 37.9 degrees C...... with control at the end of exercise (43 +/- 4 vs. 51 +/- 4 ml. 100 g(-1). min(-1); P

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

    Science.gov (United States)

    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…

  17. Influence of social activity on regional cerebral blood flow and mental function in the normal aged volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Shotai; Yamaguchi, Shuhei; Katsube, Tomoko; Kitani, Kohaku; Okada, Masanori (Shimane Medical University (Japan))

    1983-12-01

    The infuence of social activity on regional cerebral blood flow (rCBF) and mental function was studied by Xe133 inhalation method in normal aged volunteers. Subjects: The first group consisted of 33 aged volunteers living in nursing home and exposed to little social stimuli. There were 15 males (mean age of 77 years) and 18 females (77 years). The second group consisted of 49 aged community volunteers who were confirmed socially active. There were 25 males (76 years) and 24 females (72 years). All subjects were healthy persons without a past history of cerebral diseases and lung diseases. There were no difference in blood pressure and hematocrit between the two groups. The rCBF was measured by 16-ch-Novo-cerebrograph. Verbal intelligence was evaluated by the Hasegawa Simple Intelligence Scale for Aged. Performance intelligence was evaluated with the Kohs' Block Design Test. The mean rCBF in group I showed significantly lower value than that of group II, especially in the frontotemporal region. The performance intelligence was decreased in group I. However, there were no significant difference in the verbal intelligence between the two groups. 2) The aging effect on rCBF and intelligences was more prominent in group II. 3) In males, hemispheric rCBF of group I decreased bilaterally associated with the decrease of both intelligences. While the left hemispheric rCBF in females was relatively preserved as well as the preservation of verbal intelligence. These results indicate that the social environmental factors may have significant influence to aging of the brain especially in the males.

  18. EFFECT OF ELECTROACUPUNCTURE ON CEREBRAL BLOOD FLOW,VIP AND ET IN RATS WITH VASCULAR DEMENTIA

    Institute of Scientific and Technical Information of China (English)

    申国明; 徐颖; 何峰; 许冠荪

    2004-01-01

    Objective: To investigate the relationship between electroacupuncture (EA)-induced improvement of regional cerebral blood flow and the alternations of vasoactive intestinal peptide (VIP) and endothelin (ET) in rats with experimental vascular dementia (VD).Methods: 40 Wistar rats were evenly randomized into sham-operation, model, medication (Nimotone) and EA groups.Vascular dementia model was established by repeated cerebral ischemia-reperfusion which was induced by occlusion and reopen of the bilateral common carotid arteries.EA (2~200 Hz, 2~3 mA) was applied to "Baihui"(GV 20), "Dazhui"(GV 14) and "Zusanli"(ST 36) for 30 min, once daily and continuously for 15 days.The regional cerebral blood flow (rCBF) in parietal lobe and hippocampus was determined with method of hydrogen clearance; a step-down avoidance test was adopted to observe the rats' behavior change; and plasma VIP and ET contents were assayed by radioimmunoassay.Results: In comparison with sham-operation group, the correct rate of step-down avoidance test, rCBF in parietal lobe and hippocampus and plasma VIP level in VD model group lowered significantly (P<0.01) and plasma ET increased considerably (P<0.01).However, compared with model group, the correct rate of step-down avoidance test, rCBF values and plasma VIP in EA group raised obviously while plasma ET declined significantly.No significant differences were found between EA and medication groups in the 4 indexes.Conclusion: EA can raise rCBF in the parietal lobe and hippocampus, elevate plasma VIP level and reduce plasma ET in rats with VD.

  19. Differences in resting state regional cerebral blood flow assessed with 99mTc-HMPAO SPECT and brain atlas matching between depressed patients with and without tinnitus.

    Science.gov (United States)

    Gardner, A; Pagani, M; Jacobsson, H; Lindberg, G; Larsson, S A; Wägner, A; Hällstrom, T

    2002-05-01

    An increased occurrence of major depressive disorder has been reported in tinnitus patients, and of tinnitus in depressive patients. Involvement of several Brodmann areas (BAs) has been reported in tinnitus perception. The aim of this study was to assess the regional cerebral blood flow (rCBF) changes in depressed patients with and without tinnitus. The rCBF distribution at rest was compared among 45 patients with a lifetime prevalence of major depressive disorder, of whom 27 had severe tinnitus, and 26 normal healthy subjects. 99mTc-hexamethylenepropylene amine oxime (99mTc-HMPAO) single photon emission computed tomography (SPECT), using a three-headed gamma camera, was performed and the uptake in 34 functional sub-volumes of the brain bilaterally was assessed by a computerized brain atlas. Decreased rCBF in right frontal lobe BA 45 (Ptinnitus patients compared with non-tinnitus patients. The proportion of tinnitus patients with pronounced rCBF alterations in one or more of the temporal lobe BAs 41+21+22 was increased compared to gender matched controls (Ptinnitus (Ptinnitus patients only in three limbic BAs (Ptinnitus patients only in five BAs subserving auditory perception and processing (Pdepressed patients with and without tinnitus were found in this study. The rCBF alterations were distributed in the cortex and were particularly specific in the auditory cortex. These findings suggest that taking audiological symptoms into account may yield more consistent results between rCBF studies of depression.

  20. Cerebral blood flow in posterior cortical nodes of the default mode network decreases with task engagement but remains higher than in most brain regions.

    Science.gov (United States)

    Pfefferbaum, Adolf; Chanraud, Sandra; Pitel, Anne-Lise; Müller-Oehring, Eva; Shankaranarayanan, Ajit; Alsop, David C; Rohlfing, Torsten; Sullivan, Edith V

    2011-01-01

    Functional neuroimaging studies provide converging evidence for existence of intrinsic brain networks activated during resting states and deactivated with selective cognitive demands. Whether task-related deactivation of the default mode network signifies depressed activity relative to the remaining brain or simply lower activity relative to its resting state remains controversial. We employed 3D arterial spin labeling imaging to examine regional cerebral blood flow (CBF) during rest, a spatial working memory task, and a second rest. Change in regional CBF from rest to task showed significant normalized and absolute CBF reductions in posterior cingulate, posterior-inferior precuneus, and medial frontal lobes . A Statistical Parametric Mapping connectivity analysis, with an a priori seed in the posterior cingulate cortex, produced deactivation connectivity patterns consistent with the classic "default mode network" and activation connectivity anatomically consistent with engagement in visuospatial tasks. The large task-related CBF decrease in posterior-inferior precuneus relative to its anterior and middle portions adds evidence for the precuneus' heterogeneity. The posterior cingulate and posterior-inferior precuneus were also regions of the highest CBF at rest and during task performance. The difference in regional CBF between intrinsic (resting) and evoked (task) activity levels may represent functional readiness or reserve vulnerable to diminution by conditions affecting perfusion.

  1. Near-infrared spectroscopy extended with indocyanine green dye dilution for cerebral blood flow measurement: Median values in healthy volunteers

    Science.gov (United States)

    Mudra, R.; Muroi, C.; Niederer, P.; Keller, E.

    2008-09-01

    The cerebral blood flow (CBF) is an important vital parameter in neurointensive care. Currently, there is no non-invasive method for its measurement that can easily be applied at the bedside. A new tool to determine CBF is based on near-infrared spectroscopy (NIRS) applied together with indocyanine green (ICG) dye dilution. From a bilateral measurement on selected regions on the head of infrared (IR) absorption at various wavelengths during the dilution maneuver, the vascular perfusion characteristics of the two brain hemispheres can be determined in terms of mean transit time (mtt) of ICG, cerebral blood volume (CBV) and CBF. So far, on nine healthy volunteers, NIRS ICG dye dilution bihemispheric measurements were performed, which yielded to mtt given as median (range) of 9.3 s (5.1-16.3 s), CBV of 3.5 ml/100 g (1.7-4.1 ml/100 g), and CBF of 18.2 ml/(100 g×min) [11.1-48.6 ml/(100 g×min)]. Additionally, the blood flow index (BFI) was calculated with BFI= 13.8 mg/(100 g×s) [6.6-15.2 mg/(100 g×s)]. The Spearman rank correlation coefficient between CBF and BFI was RS = 0.76. However, as the Bland & Altman plot between CBFNIRS and the CBFBFI documents, the limits of agreement are rather wide (21.9±6.7). Under physiological conditions in healthy volunteers, no differences could be detected between the hemispheres.

  2. Granulocyte-Colony Stimulating Factor Increases Cerebral Blood Flow via a NO Surge Mediated by Akt/eNOS Pathway to Reduce Ischemic Injury

    Directory of Open Access Journals (Sweden)

    Hock-Kean Liew

    2015-01-01

    Full Text Available Granulocyte-colony stimulating factor (G-CSF protects brain from ischemic/reperfusion (I/R injury, and inhibition of nitric oxide (NO synthases partially reduces G-CSF protection. We thus further investigated the effects of G-CSF on ischemia-induced NO production and its consequence on regional cerebral blood flow (rCBF and neurological deficit. Endothelin-1 (ET-1 microinfused above middle cerebral artery caused a rapid reduction of rCBF (ischemia which lasted for 30 minutes and was followed by a gradual recovery of blood flow (reperfusion within the striatal region. Regional NO concentration increased rapidly (NO surge during ischemia and recovered soon to the baseline. G-CSF increased rCBF resulting in shorter ischemic duration and an earlier onset of reperfusion. The enhancement of the ischemia-induced NO by G-CSF accompanied by elevation of phospho-Akt and phospho-eNOS was noted, suggesting an activation of Akt/eNOS. I/R-induced infarct volume and neurological deficits were also reduced by G-CSF treatment. Inhibition of NO synthesis by L-NG-Nitroarginine Methyl Ester (L-NAME significantly reduced the effects of G-CSF on rCBF, NO surge, infarct volume, and neurological deficits. We conclude that G-CSF increases rCBF through a NO surge mediated by Akt/eNOS, which partially contributes to the beneficial effect of G-CSF on brain I/R injury.

  3. CBF/CMRO2 coupling measured with calibrated BOLD fMRI: sources of bias.

    Science.gov (United States)

    Leontiev, Oleg; Dubowitz, David J; Buxton, Richard B

    2007-07-15

    The coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during brain activation can be characterized by an empirical index n, the ratio of fractional CBF changes to fractional CMRO2 changes. Measurements of n have yielded varying results, and it is not known if the observed variability is due to measurement techniques or underlying physiology. The calibrated BOLD approach using hypercapnia offers a promising tool for assessing changes in CBF/CMRO2 coupling in health and disease, but potential systematic errors have not yet been characterized. The goal of this study was to experimentally evaluate the magnitude of bias in the estimate of n that arises from the way in which a region of interest (ROI) is chosen for averaging data and to relate this potential bias to a more general theoretical consideration of the sources of systematic errors in the calibrated BOLD experiment. Results were compared for different approaches for defining an ROI within the visual cortex based on: (1) retinotopically defined V1; (2) a functional CBF localizer; and (3) a functional BOLD localizer. Data in V1 yielded a significantly lower estimate of n (2.45) compared to either CBF (n=3.45) or BOLD (n=3.18) localizers. Different statistical thresholds produced biases in estimates of n with values ranging from 3.01 (low threshold) to 4.37 (high threshold). Possible sources of the observed biases are discussed. These results underscore the importance of a critical evaluation of the methodology, and the adoption of consistent standards for applying the calibrated BOLD approach to the evaluation of CBF/CMRO2 coupling.

  4. CBF/CMRO2 Coupling Measured with Calibrated-BOLD fMRI: Sources of Bias

    Science.gov (United States)

    Leontiev, Oleg; Dubowitz, David J.; Buxton, Richard B.

    2007-01-01

    The coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during brain activation can be characterized by an empirical index n, the ratio of fractional CBF changes to fractional CMRO2 changes. Measurements of n have yielded varying results, and it is not known if the observed variability is due to measurement techniques or underlying physiology. The calibrated BOLD approach using hypercapnia offers a promising tool for assessing changes in CBF/CMRO2 coupling in health and disease, but potential systematic errors have not yet been characterized. The goal of this study was to experimentally evaluate the magnitude of bias in the estimate of n that arises from the way in which a region of interest (ROI) is chosen for averaging data, and to relate this potential bias to a more general theoretical consideration of the sources of systematic errors in the calibrated BOLD experiment. Results were compared for different approaches for defining an ROI within the visual cortex based on: 1) retinotopically-defined V1; 2) a functional CBF localizer; and 3) a functional BOLD localizer. Data in V1 yielded a significantly lower estimate of n (2.45) compared to either CBF (n = 3.45) or BOLD (n = 3.18) localizers. Different statistical thresholds produced biases in estimates of n with values ranging from 3.01 (low threshold) to 4.37 (high threshold). Possible sources of the observed biases are discussed. These results underscore the importance of a critical evaluation of the methodology, and the adoption of consistent standards for applying the calibrated BOLD approach to the evaluation of CBF/CMRO2 coupling. PMID:17524665

  5. Regional cerebral blood flow in stroke by 133Xenon inhalation and emission tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Paulson, O

    1981-01-01

    A rapidly rotating single-photon emission tomograph was used to study regional cerebral blood flow by 133Xenon inhalation. Using a rotation speed of 180 degrees/5 sec a tomographic picture of the average Xenon concentration in 3 slices is obtained. By taking a sequence of 4 one-minute tomograms...... normal subjects and 10 unselected patients with stroke. The CBF tomograms localized appropriate ischemic areas in all 10 patients. In one patient the conventional x-ray tomogram was negative, while the flow tomogram clearly showed a decreased flow in consonance with the clinical findings. Regional...... cerebral blood flow measured tomographically by 133Xenon inhalation circumvents the extra-cranial contamination and the superposition of intracranial tissues that hamper 133Xenon inhalation flow studies using stationary detectors....

  6. The Longitudinal Evolution of Cerebral Blood Flow Regulation after Acute Ischaemic Stroke

    Directory of Open Access Journals (Sweden)

    Angela S.M. Salinet

    2014-08-01

    Full Text Available Background: Acute stroke is known to impair cerebral blood flow (CBF regulation, but the longitudinal changes of these effects have been poorly reported. The main CBF regulatory mechanisms [cerebral autoregulation (CA and neurovascular coupling (NVC] were assessed over 3 months after acute ischaemic stroke. Methods: Recordings of CBF velocity (CBFv, blood pressure (BP, and end-tidal CO2 were performed during 5 min baseline and 1 min passive movement of the elbow. Stroke patients were assessed Results: Fifteen acute stroke subjects underwent all 4 sessions and were compared to 22 control subjects. Baseline recordings revealed a significantly lower CBFv in the affected hemisphere within 72 h after stroke compared to controls (p = 0.02 and a reduction in CA index most marked at 2 weeks (p = 0.009. CBFv rise in response to passive arm movement was decreased bilaterally after stroke, particularly in the affected hemisphere (p Conclusion: The major novel finding of this study was that both CA and NVC regulatory mechanisms deteriorated initially following stroke onset, but returned to control levels during the recovery period. These findings are relevant to guide the timing of interventions to manipulate BP and potentially for the impact of intensive rehabilitation strategies that may precipitate acute physiological perturbations but require further exploration in a larger population that better reflects the heterogeneity of stroke. Further, they will also enable the potential influence of stroke subtype to be investigated.

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

    Science.gov (United States)

    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.

  8. High Plasma Levels of Neuropeptide Y Correlate With Good Clinical Outcome But are not Correlated to Cerebral Blood Flow or Vasospasm After Subarachnoid Hemorrhage

    DEFF Research Database (Denmark)

    Rasmussen, Rune; Stavngaard, Trine; Jessing, Iben R;

    2016-01-01

    BACKGROUND AND PURPOSE: Delayed cerebral ischemia (DCI) is a serious and frequent complication following subarachnoid hemorrhage. Treatments with convincing effect are lacking and the pathophysiology behind DCI remains poorly understood. Neuropeptide Y (NPY) is a potent endogenous vasoconstrictor...... and a role of NPY in the development of DCI has been proposed. This study investigated the relationship between plasma-NPY and cerebral blood flow (CBF), cerebral vasospasm, DCI, and clinical outcome. METHODS: In 90 patients with subarachnoid hemorrhage, NPY was measured in peripheral blood days 2 to 11. Any...... occurrence of DCI was recorded and CBF was quantified day 3 and day 8 using computed tomography (CT) perfusion. CT angiography was performed day 8. Clinical outcome was assessed after 3 months. RESULTS: No correlation was found between plasma-NPY and CBF or angiographic vasospasm. The correlation between...

  9. Ocular Blood Flow Autoregulation Mechanisms and Methods

    Directory of Open Access Journals (Sweden)

    Xue Luo

    2015-01-01

    Full Text Available The main function of ocular blood flow is to supply sufficient oxygen and nutrients to the eye. Local blood vessels resistance regulates overall blood distribution to the eye and can vary rapidly over time depending on ocular need. Under normal conditions, the relation between blood flow and perfusion pressure in the eye is autoregulated. Basically, autoregulation is a capacity to maintain a relatively constant level of blood flow in the presence of changes in ocular perfusion pressure and varied metabolic demand. In addition, ocular blood flow dysregulation has been demonstrated as an independent risk factor to many ocular diseases. For instance, ocular perfusion pressure plays key role in the progression of retinopathy such as glaucoma and diabetic retinopathy. In this review, different direct and indirect techniques to measure ocular blood flow and the effect of myogenic and neurogenic mechanisms on ocular blood flow are discussed. Moreover, ocular blood flow regulation in ocular disease will be described.

  10. Effect of acupuncture on regional cerebral blood flow at acupoints GV 20, GV. 26, LI, 4. ST. 36, SP. 6 evaluated by Tc-99m ECD brain SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Chun; Bom, Hee Seung; Kang, Hwa Jeong; Kim, Seong Min; Jeong, Hwan Jeong; Kim, Ji Yeul [College of Medicine, Dongshin Univ., Naju (Korea, Republic of); Ahn, Soo Gi [College of Medicine, Wonkwang Univ., Iksan (Korea, Republic of)

    2000-12-01

    To evaluate the effect of acupuncture on regional cerebral blood flow (rCBF) at acupoints suggested by oriental medicine to be related to the treatment of cerebrovascular diseases. Rest/acupuncture-stimulation Tc-99m ECD brain SPECT using a same-dose subtraction method was performed on 54 normal volunteers (34 males, 20 females, age range from 18 to 62 years) using six paradigms: acupuncture at acupoints GV. 20, GV. 26, LI. 4, ST. 36 and SP. 6. In the control study, needle location was chosen on a non-meridian focus 1 cm posterior to the right fibular head. All images were spatially normalized, and the differences between rest and acupuncture stimulation were statistically analyzed using SPM for Windows. Acupuncture applied at acupoint GV. 20 increased rCBF in both the anterior frontal lobes, the right frontotemporal lobes, and the left anterior temporal lobe and the left cerebellar hemisphere. Acupuncture at GV. 26 increased rCBF in the left prefrontal cortex. Acupuncture at LI. 4 increased rCBF in the left prefrontal and both the inferior frontal lobes, and the left anterior temporal lobe and the left cerebellar hemisphere. Acupuncture at ST. 36 increased rCBF in the left anterior temporal lobe, the right inferior frontal lobes, and the left cerebellum. Acupuncture at SP 6 increased rCBF in the left inferior frontal and anterior temporal lobes. In the control stimulation, no significant rCBF increase was observed. The results demonstrated a correlation between stimuation at each acupoint with increase in rCBF to the corresponding brain areas.

  11. Ocular Blood Flow Autoregulation Mechanisms and Methods

    OpenAIRE

    Xue Luo; Yu-meng Shen; Meng-nan Jiang; Xiang-feng Lou; Yin Shen

    2015-01-01

    The main function of ocular blood flow is to supply sufficient oxygen and nutrients to the eye. Local blood vessels resistance regulates overall blood distribution to the eye and can vary rapidly over time depending on ocular need. Under normal conditions, the relation between blood flow and perfusion pressure in the eye is autoregulated. Basically, autoregulation is a capacity to maintain a relatively constant level of blood flow in the presence of changes in ocular perfusion pressure and va...

  12. Crossed cerebellar diaschisis after stroke identified noninvasively with cerebral blood flow-weighted arterial spin labeling MRI

    Science.gov (United States)

    Strother, Megan K.; Buckingham, Cari; Faraco, Carlos C.; Arteaga, Daniel; Lu, Pengcheng; Xu, Yaomin; Donahue, Manus J.

    2015-01-01

    Background and Purpose Crossed cerebellar diaschisis (CCD) is most commonly investigated using hemodynamic PET and SPECT imaging. However, noninvasive MRI offers advantages of improved spatial resolution, allowing hemodynamic changes to be compared directly with structural findings and without concerns related to ionizing radiation exposure. The aim of this study was to evaluate relationships between CCD identified from cerebral blood flow (CBF)-weighted arterial spin labeling (ASL) MRI with cerebrovascular reactivity (CVR)-weighted blood oxygenation level dependent (BOLD) MRI, Wallerian degeneration, clinical motor impairment, and corticospinal tract involvement. Methods Subjects (n=74) enrolled in an ongoing observational stroke trial underwent CBF-weighted ASL and hypercapnic CVR-weighted BOLD MRI. Hemispheric asymmetry indices for basal cerebellar CBF, cerebellar CVR, and cerebral peduncular area were compared between subjects with unilateral supratentorial infarcts (n=18) and control subjects without infarcts (n=16). CCD required (1) supratentorial infarct and (2) asymmetric cerebellar CBF (>95% confidence interval relative to controls). Results In CCD subjects (n=9), CVR (p=0.04) and cerebral peduncular area (p < 0.01) were significantly asymmetric compared to controls. Compared to infarct subjects not meeting CCD criteria (n=9), CCD subjects had no difference in corticospinal tract location for infarct (p=1.0) or motor impairment (p=0.08). Conclusions CCD correlated with cerebellar CVR asymmetry and Wallerian degeneration. These findings suggest that noninvasive MRI may be a useful alternative to PET or SPECT to study structural correlates and clinical consequences of CCD following supratentorial stroke. PMID:26724658

  13. Comparison of global cerebral blood flow measured by phase-contrast mapping MRI with (15) O-H2 O positron emission tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob;

    2017-01-01

    PURPOSE: To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by (15) O-H2 O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated...... of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1 -weighted anatomical MR-scan. RESULTS: Mean CBF was 34.9 ± 3.4 mL/100 g...... in vivo against an accepted reference technique. MATERIALS AND METHODS: Same-day measurements of CBF by (15) O-H2 O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement...

  14. Single photon emission CT perfusion imaging of cerebral blood flow of early syphilis patients

    Institute of Scientific and Technical Information of China (English)

    施辛; 吴锦昌; 刘增礼; 唐军; 苏玉华

    2003-01-01

    Objective To injvestigate the cerebral blood flow of patients with early syphilis. Methods 99Tcm-ECD as brain perfusion imaging agent was used in single photon emission computed tomography (SPECT) for 32 patients with early syphilis and 15 controls. Visual analyses were made on every BSPECT image. Results The 32 patients with early syphilis had general, patchy hypoperfusion of cerebral blood flow. Fourteen of the 32 patients had 48 episodes of marked patchy hypoperfusion of rCBF. The responsible areas of hypoperfusion in a patchy distribution involved the left frontal lobe (6 episodes), right frontal lobe (3), left parietal lobe (7), right parietal lobe (6), left temporal lobe (11), right temporal lobe (5), left occipital lobe (3), left basal ganglia (3), cerebellum (1), and nerve nuceus (1). No abnormality was found in the control group.Conclusions Cerebral blood flow abnormalities exist in patients with early syphilis. General patchy hypoperfusion on SPECT imaging is common.

  15. Changes in cerebral blood flow after cognitive behavior therapy in patients with panic disorder: a SPECT study

    Directory of Open Access Journals (Sweden)

    Seo HJ

    2014-04-01

    Full Text Available Ho-Jun Seo,1 Young Hee Choi,2 Yong-An Chung,3 Wangku Rho,1 Jeong-Ho Chae11Department of Psychiatry, College of Medicine, The Catholic University of Korea, Seoul, South Korea; 2Metta Institute of Cognitive Behavior Therapy, Seoul, South Korea; 3Department of Radiology, Nuclear Medicine, College of Medicine, The Catholic University of Korea, Seoul, South KoreaAim: Inconsistent results continue to be reported in studies that examine the neural correlates of cognitive behavioral therapy (CBT in patients with panic disorder. We examined the changes in regional cerebral blood flow (rCBF associated with the alleviation of anxiety by CBT in panic patients.Methods: The change in rCBF and clinical symptoms before and after CBT were assessed using single photon emission computed tomography and various clinical measures were analyzed.Results: Fourteen subjects who completed CBT showed significant improvements in symptoms on clinical measures, including the Panic and Agoraphobic Scale and the Anxiety Sensitivity Index-Revised. After CBT, increased rCBF was detected in the left postcentral gyrus (BA 43, left precentral gyrus (BA 4, and left inferior frontal gyrus (BA 9 and BA 47, whereas decreased rCBF was detected in the left pons. Correlation analysis of the association between the changes in rCBF and changes in each clinical measure did not show significant results.Conclusion: We found changes in the rCBF associated with the successful completion of CBT. The present findings may help clarify the effects of CBT on changes in brain activity in panic disorder.Keyword: single photon emission computed tomography (SPECT, anxiety, neural correlate, brain activity

  16. The changes of regional cerebral blood flow: successful pain relief of intractable CRPS type II patients by motor cortex stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J. A.; Son, H. S.; Kim, S. H.; Jung, S. G [The Catholic University of Korea, Seoul (Korea, Republic of)

    2004-07-01

    Authors report the effectiveness of MCS in extraordinarily extended pain due to intractable CRPS type II and rCBF study result for mechanism of pain control by MCS. A 43-year-old male presented severe spontaneous burning pain in his left hand and forearm and allodynia over the left arm and left hemibody. Authors planned MCS as a neuromodulation therapy for this intractable peripheral neuropathic pain patient because further neurodestructive procedure did not work anymore and have a potential risk of further aggrevation of neuopathic pain. We performed baseline and stimulation brain perfusion SPECT using 20 mCi of Tc-99m ECD. The baseline CBD studies were done with stimulator 'off' state and stimulation studies were done after stimulator 'on' with satisfactory pain relief. For the stimulation study, the radioisotope was injected immediately after pain-relief and the images were taken about 50 minutes after injection of radioisotope. In resting rCBF in the patient was compared with normal control datas, we found significant increase in rCBF in the bilateral prefrontal cortex, right dorsolateral prefrontal cortex, right superior temporal gyrus, left temporooccipital area. When rCBF datas obtained after alleviation of pain with stimulator 'on' . there were significant increase in rCBF in bilateral prefrontal cortex and left temporoocipital area. After subtraction of ECD SPECT, we found significant increase in rCBF in the right premotor and supplementary motor cortex left sensorimotor cortex, right cingulated cortex, right posterior insular cortex, right anterior limb of internal capsule. left orbitofrontal cortex and right pyramidal tract in cerebral peduncle. Authors report exellent pain control by MCS in a case of severe CRPS type II with hemibody involvement and regional cerebral blood flow changes according to successful pain control.

  17. Regional cerebral blood flow in acute stage ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki (Akita Univ. (Japan). School of Medicine)

    1989-03-01

    During the period from February 1984 through June 1985, single photon emission computerized tomography (SPECT) with xenon-133 inhalation method has been performed for the measurement of regional cerebral blood flow (rCBF) during the first 48 hours of onset of cerebral infarction (n=71) and transient ischemic attack (n=21). X-ray CT (CT) and carotid arteriography were concurrently performed in all the patients. In repeated studies performed for 15 normal volunteers, rCBF measurement by SPECT was found reproducible. Mean values of rCBF for the right and left cerebral hemispheres were 60.3{plus minus}6.52 and 61.8{plus minus}6.91 ml/100 g/min, respectively. For cerebral infarction, ischemic foci corresponding to clinical symptoms were detected more frequently on SPECT than on CT (93% vs 63%). In all of the evaluable 35 patients with cerebral infarction, rCBF within the first 8 hours of onset was decreased: 31.0 ml/100 g/min for the internal carotid artery (ICA) occlusion and 36.0 ml/100 g/min for the middle cerebral artery (MCA) occlusion. Crossed cerebellar diaschisis was observed in 50% (9/18) for ICA occlusion and 37% (14/38) for MCA occlusion. For transient ischemic attack, there was no significant difference in the detection of ischemic foci between SPECT and CT (38% vs 43%). In detecting small foci especially in the deep regions such as the basal ganglia, SPECT was inferior to CT. Mean rCBF for transient ischemic attack tended to be lower than the normal rCBF (50.7 ml/100 g/min for the right cerebral hemisphere and 50.6 ml/100 g/min for the left cerebral hemisphere). SPECT may aid in predicting prognosis and chosing treatment strategy, as well as in determining cerebral hemodynamics. (N.K.).

  18. Effect of histamine on regional cerebral blood flow of the parietal lobe in rats.

    Science.gov (United States)

    Yang, Peng-Bo; Chen, Xin-Lin; Zhao, Jian-Jun; Zhang, Jian-Shui; Zhang, Jun-Feng; Tian, Yu-Mei; Liu, Yong

    2010-09-01

    Histamine is a powerful modulator that regulates blood vessels and blood flow. The effect of histamine on the extracortical vessels has been well described, while much less is known about the effect of histamine on intracortical vessels. In this study, we investigated the effect of histamine on regional cerebral blood flow in rat parietal lobe with laser Doppler flowmetry. The pharmacological characteristics of distinct ways (intracerebroventricular injection, intraperitoneal injection, and cranial window infusion) in applying histamine to the brain were also obtained and compared. Histamine applied in three ways all produced a decrease of rCBF in parietal lobe in a concentration-dependent manner. Cranial window infusion was the most effective way and intraperitoneal injection of L-histidine was the most ineffective, although it is a simple and applied way. To determine which type of receptor takes part in the vessel contraction induced by histamine, H1 receptor antagonist, diphenhydramine, and H2 receptor antagonist, cimetidine, were applied, respectively, before histamine administration. When the injection of cimetidine was conducted in advance, histamine still resulted in a decrease of infusion amount; while the injection of diphenhydramine was conducted in advance, the infusion of blood amount wasn't changed. These findings indicated that histamine could result in a reduction of rCBF in the rat parietal lobe and this effect of histamine may attribute partly to its combination with H1 receptor.

  19. Luminance contrast of a visual stimulus modulates the BOLD response more than the cerebral blood flow response in the human brain.

    Science.gov (United States)

    Liang, Christine L; Ances, Beau M; Perthen, Joanna E; Moradi, Farshad; Liau, Joy; Buracas, Giedrius T; Hopkins, Susan R; Buxton, Richard B

    2013-01-01

    The blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI) depends on the evoked changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) in response to changes in neural activity. This response is strongly modulated by the CBF/CMRO(2) coupling relationship with activation, defined as n, the ratio of the fractional changes. The reliability of the BOLD signal as a quantitative reflection of underlying physiological changes depends on the stability of n in response to different stimuli. The effect of visual stimulus contrast on this coupling ratio was tested in 9 healthy human subjects, measuring CBF and BOLD responses to a flickering checkerboard at four visual contrast levels. The theory of the BOLD effect makes a robust prediction-independent of details of the model-that if the CBF/CMRO(2) coupling ratio n remains constant, then the response ratio between the lowest and highest contrast levels should be higher for the BOLD response than the CBF response because of the ceiling effect on the BOLD response. Instead, this response ratio was significantly lower for the BOLD response (BOLD response: 0.23 ± 0.13, mean ± SD; CBF response: 0.42 ± 0.18; p=0.0054). This data is consistent with a reduced dynamic range (strongest/weakest response ratio) of the CMRO(2) response (~1.7-fold) compared to that of the CBF response (~2.4-fold) as luminance contrast increases, corresponding to an increase of n from 1.7 at the lowest contrast level to 2.3 at the highest contrast level. The implication of these results for fMRI studies is that the magnitude of the BOLD response does not accurately reflect the magnitude of underlying physiological processes.

  20. Stratification of cerebral hemodynamics of child moyamoya disease using CBF SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawara, Jyoji; Saito, Norihiro; Osato, Toshiaki; Kamiyama, Kenji; Takeda, Rihei; Nakamura, Hirohiko [Nakamura Memorial Hospital, Sapporo (Japan)

    2002-12-01

    In order to make sure the stratification of cerebral hemodynamics of child moyamoya disease, we evaluated {sup 123}I-IMP SPECT before and after surgical revascularization. The aim of this paper is to establish the semiquantitative parameters that can be applied to estimate severity of hemodynamic cerebral ischemia instead of quantitative parameters. Quantitative studies using IMP-autoradiography (ARG) method were performed on thirteen patients to measure resting regional cerebral blood flow (rCBF), and vascular reserve (rVR): (Diamox-activated rCBF/resting rCBF-1) x 100%. Semiquantitative parameters were calculated from the ratio of region of interest (ROI) counts in the anterior cerebral artery (ACA) and middle cerebral artery (MCA) territory to the dominant cerebellum counts (ROI/Ce ratio) at resting and Diamox-activated conditions. From the quantitative study, both mean resting rCBF less than 40 ml/100 g/min and rVR less than 10% could indicate stage 2 hemodynamic cerebral ischemia. The prediction of stage 2 ischemia using semiquantitative parameters (resting ROI/Ce ratio less than 0.9 and Diamox-activated ROI/Ce ratio less than 0.85 in the MCA territory) was not statistically different comparison to the diagnosis using quantitative parameters (using Fisher exact test<0.0001, Sensitivity and specificity were 87.5% and 90.9%, respectively). The ROI/Ce ratio can be utilized as simple parameters instead of quantitative parameters. (author)

  1. Chronically impaired autoregulation of cerebral blood flow in long-term diabetics

    DEFF Research Database (Denmark)

    Bentsen, N; Larsen, B; Lassen, N A

    1975-01-01

    of the patient. Regression analysis was carried out on the results in order to quantify autoregulatory capacity. In the control patients CBF did not vary with moderate blood pressure variations, indicating normal autoregulation. In four of the 16 diabetic patients CBF showed significant pressure dependency...

  2. Cerebral blood flow measured by arterial-spin labeling MRI: A useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016 (China); Zhang, Long Jiang, E-mail: kevinzhlj@163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Zhong, Jianhui [Department of Imaging Sciences, University of Rochester School of Medicine and Dentistry, Box648, 601 Elmwood Avenue, Rochester, NY 14642-8648 (United States); Wang, Ze [Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3900 Chestnut St., Philadelphia, PA 19104 (United States); Qi, Rongfeng; Shi, Donghong [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Lu, Guang Ming, E-mail: cjr.luguangming@vip.163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China)

    2013-11-01

    Purpose: To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE). Materials and methods: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child–Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients. Results: The gray matter CBF of MHE patients (71.09 ± 11.88 mL min{sup −1} 100 g{sup −1}) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min{sup −1} 100 g{sup −1}, P < 0.01) and controls (52.09 ± 9.27 mL min{sup −1} 100 g{sup −1}, P < 0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P < 0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P < 0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min{sup −1} 100 g{sup −1}. CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right

  3. Dual role of cerebral blood flow in regional brain temperature control in the healthy newborn infant.

    Science.gov (United States)

    Iwata, Sachiko; Tachtsidis, Ilias; Takashima, Sachio; Matsuishi, Toyojiro; Robertson, Nicola J; Iwata, Osuke

    2014-10-01

    Small shifts in brain temperature after hypoxia-ischaemia affect cell viability. The main determinants of brain temperature are cerebral metabolism, which contributes to local heat production, and brain perfusion, which removes heat. However, few studies have addressed the effect of cerebral metabolism and perfusion on regional brain temperature in human neonates because of the lack of non-invasive cot-side monitors. This study aimed (i) to determine non-invasive monitoring tools of cerebral metabolism and perfusion by combining near-infrared spectroscopy and echocardiography, and (ii) to investigate the dependence of brain temperature on cerebral metabolism and perfusion in unsedated newborn infants. Thirty-two healthy newborn infants were recruited. They were studied with cerebral near-infrared spectroscopy, echocardiography, and a zero-heat flux tissue thermometer. A surrogate of cerebral blood flow (CBF) was measured using superior vena cava flow adjusted for cerebral volume (rSVC flow). The tissue oxygenation index, fractional oxygen extraction (FOE), and the cerebral metabolic rate of oxygen relative to rSVC flow (CMRO₂ index) were also estimated. A greater rSVC flow was positively associated with higher brain temperatures, particularly for superficial structures. The CMRO₂ index and rSVC flow were positively coupled. However, brain temperature was independent of FOE and the CMRO₂ index. A cooler ambient temperature was associated with a greater temperature gradient between the scalp surface and the body core. Cerebral oxygen metabolism and perfusion were monitored in newborn infants without using tracers. In these healthy newborn infants, cerebral perfusion and ambient temperature were significant independent variables of brain temperature. CBF has primarily been associated with heat removal from the brain. However, our results suggest that CBF is likely to deliver heat specifically to the superficial brain. Further studies are required to assess the

  4. Reduced serotonin synthesis and regional cerebral blood flow after anxiolytic treatment of social anxiety disorder.

    Science.gov (United States)

    Frick, Andreas; Åhs, Fredrik; Appel, Lieuwe; Jonasson, My; Wahlstedt, Kurt; Bani, Massimo; Merlo Pich, Emilio; Bettica, Paolo; Långström, Bengt; Lubberink, Mark; Fredrikson, Mats; Furmark, Tomas

    2016-11-01

    Social anxiety disorder (SAD) is associated with increased fear-related neural activity in the amygdala and we recently found enhanced serotonin synthesis rate in the same region. Anxiolytic agents like selective serotonin re-uptake inhibitors (SSRIs) and neurokinin-1 receptor (NK1R) antagonists reduce amygdala activity and may attenuate serotonin formation according to animal studies. Here, we examined the effects of SSRI pharmacotherapy, NK1R antagonism, and placebo on serotonin synthesis rate in relation to neural activity, measured as regional cerebral blood flow (rCBF), and symptom improvement in SAD. Eighteen SAD patients were randomized to receive daily double-blind treatment for six weeks either with the SSRI citalopram (n=6; 40mg), the NK1R antagonist GR205171 (n=6; 5mg; 4 weeks following 2 weeks of placebo), or placebo (n=6). Serotonin synthesis rate at rest and rCBF during stressful public speaking were assessed, before and after treatment, using positron emission tomography with the tracers [(11)C]5-hydroxytryptophan and [(15)O]water respectively. The Liebowitz Social Anxiety Scale (LSAS-SR) indexed symptom severity. All groups exhibited attenuated amygdala serotonin synthesis rate after treatment, which was associated with reduced amygdala rCBF during public speaking and accompanied by symptom improvement. These results are consistent with the notion that serotonin in the amygdala exerts an anxiogenic influence and, conversely, that anxiolysis is achieved through decreased serotonin formation in the amygdala.

  5. Protective effects of taurine in traumatic brain injury via mitochondria and cerebral blood flow.

    Science.gov (United States)

    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.

  6. Cerebral blood flow and cerebrovascular reserve capacity in patients with occlusion or severe stenosis of cerebral arterial trunk

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaga, Shinya; Tanaka, Akira; Nakayama, Yoshiya; Tomonaga, Masamichi [Fukuoka Univ., Chikushino (Japan). Chikushi Hospital

    1997-12-01

    The cerebral blood flow (CBF) and the cerebrovascular reserve capacity (CVRC) were sequentially measured using a xenon enhanced CT scan in patients with transient ischemic attack or minor stroke due to an occlusion or a severe stenosis of the cerebral arterial trunk. The patients consisted of twelve males and one female ranging from 37 to 71 years of age (53 years on average). The vascular lesion was located in the internal carotid artery (7 patients) and in the middle cerebral artery (6 patients). Eleven patients received antiplatelet drug therapy, while two other patients underwent STA-MCA anastomosis. The CBF measurements were initially done within one month after the attack and then from 6 to 24 months (12 months on average) after the first study. Only one of 13 patients demonstrated a reattack during the period of observation and the CVRC decreased to 0% from the 14% level observed prior to the reattack, although the CBF was preserved. In the other twelve patients without a reattack, the CVRC was found to improve to 29.4% from 9.9% with statistical significance, even though the CBF remained the same in the first study. This study suggests hemodynamic insult to be closely related to the decreased in the CVRC, while STA-MCA anastomosis does not for prevent hemodynamic reattack based on a decrease in the CVRC in the early stage. (author)

  7. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET

    DEFF Research Database (Denmark)

    Iida, H; Law, I; Pakkenberg, B

    2000-01-01

    formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...... onto the PET images in which regional CBF values and the water perfusable tissue fraction for the cortical gray matter tissue (hence the volume of gray matter) were estimated. After the PET study, the animals were killed and stereologic analysis was performed to assess the gray matter mass...

  8. Relations between neuropsychological findings and lateral asymmetries of cerebral blood flow measured by SPECT in dementia of Alzheimer type

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Nahoko; Soma, Yoshiaki; Ootsuki, Mika [Takeda General Hospital, Aizu-Wakamatsu, Fukushima (Japan)

    1993-10-01

    We studied 16 right-handed patients clinically diagnosed as dementia of Alzheimer type (6 men, 10 women; aged 63-85, mean 72.8 years). The average duration of symptoms was 2.7 years. Dementia ranged from mild to moderately severe. None had clinical or laboratory evidence of cerebrovascular disease (Hachinski ischemic scores for all patients were 4 or below 4). All received the Wechsler Adult Intelligence Scale (WAIS), Mini-mental State Test (MMS) and Western Aphasia Battery (WAB, First Japanese edition, 1986). Regional cerebral blood flow (rCBF) was evaluated by single photon emission CT (SPECT) with {sup 123}I-N-isopropyl-p-iodoamphetamine ({sup 123}I-IMP), using the Matsuda`s quantitative method. Regional tracer uptake was measured in regions of interests (ROIs) over right and left frontal, temporal, parietal and occipital cortical regions; basal ganglia; and cerebellar hemispheres. The subjects were divided into three groups on the basis of lateral asymmetries in the temporal and parietal cortexes of rCBF (leftCBF for each ROI between left and right sides differs by more than 10%. General score (MMS, T-IQ) was not correlated with asymmetry of cerebral blood flow. Verbal IQ in patients with predominant hypoperfusion of left temporal and parietal lobe was significantly lower than other group, while performance IQ and WAB constructive scores were lower in those with right hemispheric hypoperfusion (p<0.05). We concluded that cerebral blood flow asymmetry by SPECT was related significantly to the deficit of language and constructive function in patients with dementia of Alzheimer type. Decreased rCBF in the left temporoparietal lobe was associated with language dysfunction, and that in the right hemisphere, with constructive dysfunction. (author).

  9. Differential Effects of Acetylcholinesterase Inhibitors on Clinical Responses and Cerebral Blood Flow Changes in Patients with Alzheimer's Disease: A 12-Month, Randomized, and Open-Label Trial

    Directory of Open Access Journals (Sweden)

    Soichiro Shimizu

    2015-04-01

    Full Text Available Background/Aims: The present study evaluated the differences in treatment outcomes and brain perfusion changes among 3 types of acetylcholinesterase inhibitors (AchEIs, i.e. donepezil, rivastigmine, and galantamine. Methods: This was a prospective, longitudinal, randomized, open-label, 3-arm (donepezil, rivastigmine, or galantamine, parallel-group, 12-month clinical trial carried out in 55 patients with AD. Results: At 6 months, the results of the Mini-Mental State Examination (MMSE and the Trail Making Test (TMT-Part A showed an improvement versus baseline in the donepezil treatment group. All groups showed a significant increase in regional cerebral blood flow (rCBF, mainly in the frontal lobe. Significant rCBF reduction was observed in the temporal lobe and cingulate gyrus in all 3 groups. Conclusion: AchEI treatment prevents the progression of cognitive impairment and increases the relative rCBF in the frontal lobe.

  10. Autoregulation of cerebral blood flow to changes in arterial pressure in mild Alzheimer's disease.

    Science.gov (United States)

    Zazulia, Allyson R; Videen, Tom O; Morris, John C; Powers, William J

    2010-11-01

    Studies in transgenic mice overexpressing amyloid precursor protein (APP) demonstrate impaired autoregulation of cerebral blood flow (CBF) to changes in arterial pressure and suggest that cerebrovascular dysfunction may be critically important in the development of pathological Alzheimer's disease (AD). Given the relevance of such a finding for guiding hypertension treatment in the elderly, we assessed autoregulation in individuals with AD. Twenty persons aged 75±6 years with very mild or mild symptomatic AD (Clinical Dementia Rating 0.5 or 1.0) underwent (15)O-positron emission tomography (PET) CBF measurements before and after mean arterial pressure (MAP) was lowered from 107±13 to 92±9 mm Hg with intravenous nicardipine; (11)C-PIB-PET imaging and magnetic resonance imaging (MRI) were also obtained. There were no significant differences in mean CBF before and after MAP reduction in the bilateral hemispheres (-0.9±5.2 mL per 100 g per minute, P=0.4, 95% confidence interval (CI)=-3.4 to 1.5), cortical borderzones (-1.9±5.0 mL per 100 g per minute, P=0.10, 95% CI=-4.3 to 0.4), regions of T2W-MRI-defined leukoaraiosis (-0.3±4.4 mL per 100 g per minute, P=0.85, 95% CI=-3.3 to 3.9), or regions of peak (11)C-PIB uptake (-2.5±7.7 mL per 100 g per minute, P=0.30, 95% CI=-7.7 to 2.7). The absence of significant change in CBF with a 10 to 15 mm Hg reduction in MAP within the normal autoregulatory range demonstrates that there is neither a generalized nor local defect of autoregulation in AD.

  11. Impaired autoregulation of cerebral blood flow in long-term type I (insulin-dependent) diabetic patients with nephropathy and retinopathy

    DEFF Research Database (Denmark)

    Kastrup, J; Rørsgaard, S; Parving, H H;

    1986-01-01

    . Cerebral blood flow was measured by the intravenous 133Xenon method. Mean arterial blood pressure was elevated approximately 30 mmHg by intravenous infusion of angiotensin amide II and lowered about 10 mmHg by intravenous infusion of trimethaphan camsylate. In the control subjects the flow/pressure curve...... was horizontal indicating perfect autoregulation. In the diabetic patients the flow/pressure curve showed a significant slope with a 1.9% change in CBF per 10 mmHg change in mean arterial blood pressure as compared to a slope value of -0.4% in the control subjects (P less than 0.05). Our results confirm...

  12. The effects of dopamine on regional cerebral blood flow in patients with Parkinson`s disease before and after L-dopa. Measurement by Xe-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Aiba, Ikuko [Nagoya Univ. (Japan). School of Medicine; Indo, Toshikatsu; Takahashi, Akira

    1994-11-01

    Regional cerebral blood flow (rCBF) was measured using the stable xenon enhanced CT method in previously untreated 13 patients with Parkinson`s disease to evaluate CBF abnormality related to dysfunction of the nigrostriatal dopaminergic neurons. The patients comprised 5 men and 8 women with Hoehn-Yahr stage II-III. Age at onset ranged from 51 to 73 years (mean{+-}SD, 61.8{+-}8.9) and the duration of illness ranged from 1 to 96 months (15.1{+-}24.1 months). In this series, there was no clinical evidence of hypertension, diabetes mellitus and cognitive impairment. rCBF was measured during 4-5-minutes inhalation, of 33% stable xenon gas-67% oxygen. The first measurement of rCBF was performed in all of the patients before L-dopa treatment. After initiation of L-dopa treatment (333.3{+-}47.1 mg/day), the second measurement was carried out in 6 patients (1 man and 5 women) who had shown symptomatic improvement. The interval between both measurements was 57.7{+-}16.9 days. The following results were obtained. (1) No significant CBF asymmetry was noted in any of the striatum, pallidum, thalamus, cerebrum, cerebellum and frontal lobe in untreated patients with Parkinson`s disease. (2) After L-dopa treatment, rCBF was significantly increased only in the striatum as compared with the pretreatment level (51.9{+-}9.3{yields}63.1{+-}9.9 ml/100g/min, p<0.01). (3) This increase was significantly greater on the more severely affected side (contralateral to the predominantly symptomatic limb) (p<0.05). These results suggest that the increase of rCBF in the striatum is closely related to functional improvement of the nigrostriatal dopaminergic neurons. (author).

  13. Cerebral blood flow of patients with age-associated memory impairment and the early stage of Alzheimer`s disease. A study by SPECT using the ARG method

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Akiko; Kitamura, Shin; Nagazumi, Atushi; Terashi, Akiro [Nippon Medical School, Tokyo (Japan)

    1998-04-01

    In order to further understand the pathology of Alzheimer`s disease (AD), we have utilized image analysis in diagnosing the early stages of AD in patients with cognitive disorders. CT and MRI, however, have not been feasible since only atrophy is seen and it is difficult to differentiate the changes in AD from age associated changes. In this study we tried to determine whether regional cerebral blood flow (rCBF) measurements using single photon emission CT (SPECT) are feasible for the early diagnosis of AD. Regional CBF (rCBF) was measured using SPECT in three subject groups: Age-associated memory impairment (AAMI, n=9), mild AD (n=16), and normal aged patients (mean age=68.3; n=20). The subjects were then observed for three years. The region of interest (ROI) for the medial temporal lobe was set at OM-30deg to cover the maximum area of the hippocampus. The absolute values of rCBF in the frontal, temporal, and parietal lobes and the cerebellum were significantly lower in the mild AD subjects than in the normal aged subjects. A significant decrease in rCBF was also seen in the medial temporal lobe in both the AD and the AAMI subjects compared to the normal controls. During the three years of follow up, no cases of dementia were seen in the AAMI subjects. However, there were two patients who appeared to have difficulty in adapting to daily life due to amnesia, one with a decrease in rCBF of the medial temporal lobe on the second SPECT, and the other showing a low rCBF the first time. This study suggests that AAMI subjects may comprise both AD and normal subjects. Therefore a more prospective study is needed. (author)

  14. Quantitative Cerebral Blood Flow Measurements Using MRI

    OpenAIRE

    Muir, Eric R; Watts, Lora Talley; Tiwari, Yash Vardhan; Bresnen, Andrew; Timothy Q Duong

    2014-01-01

    Magnetic resonance imaging utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.

  15. The CBF threshold and dynamics for focal cerebral infarction in spontaneously hypertensive rats.

    Science.gov (United States)

    Jacewicz, M; Tanabe, J; Pulsinelli, W A

    1992-05-01

    Two strategies were used to estimate the blood flow threshold for focal cerebral infarction in spontaneously hypertensive rats (SHRs) subjected to permanent middle cerebral artery and common carotid artery occlusion (MCA/CCAO). The first compared the volume of cortical infarction (24 h after ischemia onset) to the volumes of ischemic cortex (image analysis of [14C]iodoantipyrine CBF autoradiographs) perfused below CBF values less than 50 (VIC50) and less than 25 ml 100 g-1 min-1 (VIC25) at serial intervals during the first 3 h of ischemia. The infarct process becomes irreversible within 3 h in this model. In the second, measurements of CBF at the border separating normal from infarcted cortex at 24 h after ischemia onset were used as an index of the threshold. During the first 3 h of ischemia, VIC50 increased slightly to reach a maximum size at 3 h that closely matched the 24 h infarct volume. VIC25, in contrast, consistently underestimated the infarct volume by a factor of 2-3. CBF at the 24 h infarct border averaged 50 ml 100 g-1 min -1. Taken together, the results indicate that the CBF threshold for infarction in SHRs approaches 50 ml 100 g-1 min-1 when ischemia persists for greater than or equal to 3 h. This threshold value is approximately three times higher than in primates. Since cortical neuronal density is also threefold greater in rats than in primates, the higher injury threshold in the rat may reflect a neuronal primacy in determining the brain's susceptibility to partial ischemia.

  16. Regional and voxel-wise comparisons of blood flow measurements between dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and arterial spin labeling (ASL) in brain tumors.

    Science.gov (United States)

    White, Carissa M; Pope, Whitney B; Zaw, Taryar; Qiao, Joe; Naeini, Kourosh M; Lai, Albert; Nghiemphu, Phioanh L; Wang, J J; Cloughesy, Timothy F; Ellingson, Benjamin M

    2014-01-01

    The objective of the current study was to evaluate the regional and voxel-wise correlation between dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) measurement of cerebral blood flow (CBF) in patients with brain tumors. Thirty patients with histologically verified brain tumors were evaluated in the current study. DSC-MRI was performed by first using a preload dose of gadolinium contrast, then collecting a dynamic image acquisition during a bolus of contrast, followed by posthoc contrast agent leakage correction. Pseudocontinuous ASL was collected using 30 pairs of tag and control acquisition using a 3-dimensional gradient-echo spin-echo (GRASE) acquisition. All images were registered to a high-resolution anatomical atlas. Average CBF measurements within regions of contrast-enhancement and T2 hyperintensity were evaluated between the two modalities. Additionally, voxel-wise correlation between CBF measurements obtained with DSC and ASL were assessed. Results demonstrated a positive linear correlation between DSC and ASL measurements of CBF when regional average values were compared; however, a statistically significant voxel-wise correlation was only observed in around 30-40% of patients. These results suggest DSC and ASL may provide regionally similar, but spatially different measurements of CBF.

  17. Regional cerebral blood flow measured with N-isopropyl-p-[[sup 123]I]iodoamphetamine single-photon emission tomography in patients with Joseph disease

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Naoya (Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan)); Odano, Ikuo (Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan)); Nishihara, Mamiko (Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan)); Yuasa, Tatsuhiko (Dept. of Neurology, Tokyo Medical and Dental Univ. School of Medicine, Tokyo (Japan)); Sakai, Kunio (Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan))

    1994-07-01

    Regional cerebral blood flow (rCBF) was measured in five Japanese patients who were clinically diagnosed as having Joseph disease, also called Machado-Joseph disease or Azorean disease, using N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and single-photon emission tomography (SPET). Cerebellar atrophy was evaluated by a five-step rating scale as defined on X-ray computed tomography (X-CT). Compared with ten age-matched normal controls (mean cerebellar CBF [+-] SD: 66.9 [+-] 6.6 ml/100 g/min), rCBF in patients with Joseph disease was significantly decreased in the cerebellum (mean [+-] SD: 50.2 [+-] 7.3 ml/100 g/min). No significant relationship, however, was found between the decrease in rCBF in the cerebellum and the degree of cerebellar atrophy on X-CT. rCBF in the cerebellum was minimally decreased in one patient who had severe cerebellar atrophy and in two patients with moderate atrophy. These data may support the findings that Purkinje cells in the cerebellum are almost normal in Joseph disease, and that the granular and molecular layers remain intact in spite of cortical atrophy of the cerebellum. It is concluded that [[sup 123]I]-IMP SPET is able to identify pathological and metabolic changes in the cerebellum that do not appear on X-CT or magnetic resonance imaging, and thus is useful for the diagnosis of Joseph disease. (orig.)

  18. Controlled study on the effect of pentoxifylline and an ergot alkaloid derivative on regional cerebral blood flow in patients with chronic cerebrovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, A.; Tsuda, Y.

    1988-05-01

    Regional cerebral blood flow (rCBF) in 90 patients with CBF decreased due to vascular diseases was studied by using the xenon 133 inhalation technique and a 32-detector setup. Whereas 30 patients received their standard basic therapy only and were regarded as controls, 30 others received 3 x 2 mg/day of an ergot alkaloid (co-dergocrine mesylate), and 30 others received 3 x 400 mg pentoxifylline (slow-release formulation)/day orally. Therapy was performed for eight weeks and CBF measured before start of treatment, after a four-week treatment period, and at the end of the study. CBF did not change significantly in the control group; both the pentoxifylline and the ergot alkaloid group presented with a significant increase in the CBF. This positive effect was significantly more pronounced in the pentoxifylline group and affected more ischemic than other brain tissues. In addition, symptoms like sleep disturbances, vertigo, and tinnitus improved significantly during the pentoxifylline observation period.

  19. CBF and CMRo/sub 2/ during craniotomy for small supratentorial cerebral tumours in enflurane anaesthesia. A dose-response study

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, J.B.; Cold, G.E.; Eriksen, H.O.; Eskesen, V.; Blatt-Lyon, B.

    1986-01-01

    In 14 patients with supratentorial cerebral tumors with midline shift less than or equal to 10 mm, cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRo/sub 2/) were measured twice on the contralateral side of the craniotomy, using a modification of the Kety and Schmidt method. For induction of anaesthesia, thiopental, fentanyl and pancuronium were used. The anaesthesia was maintained with enflurane 1% in nitrous oxide 67%. Moderate hypocapnia to a level averaging 4.3 kPa was achieved. The patients were divided into two groups. In group 1 (n=7), 1% enflurane was used throughout the anaesthesia, and CBF and CMRo/sub 2/ measured about 70 min after induction averaged 30.1 ml 100 g/sup -1/ min/sub -1/ and 1.98 ml O/sub 2/ 100 g/sup -1/ min/sup -1/, respectively. During the second CBF study 1 h later, CBF and CMRo/sub 2/ were unchanged (P>0.05). In group 2 (n=7), the inspiratory enflurane concentration was increased from 1 to 2% after the first CBF measurement. In this group a significant decrease in CMRo/sub 2/ was observed, while CBF was unchanged. In six patients EEG was recorded simultaneously with the CBF measurements. In patients subjected to increasing enflurane concentration (Group 2), a suppression in the EEG activity was observed without spike waves. It is concluded that enflurane induces a dose-related decrease in CMRo/sub 2/ and suppression in the EEG activity, whereas CBF was unchanged.

  20. A comparative study of simple methods to quantify cerebral blood flow with acetazolamide challenge by using iodine-123-IMP SPECT with one-point arterial sampling

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, Masaki [Niigata Univ. (Japan). School of Health Sciences; Odano, Ikuo

    2000-04-01

    The aim of this study was to compare the accuracy of simplified methods for quantifying rCBF with acetazolamide challenge by using {sup 123}I-N-isopropyl-p-iodoamphetamine (IMP) and SPECT with one-point arterial sampling. After acetazolamide administration we quantified rCBF in 12 subjects by the following three methods: (a) the modified microsphere method, (b) the IMP-autoradiographic (ARG) method based on a two-compartment one-parameter model, and (c) the simplified method based on a two-compartment two-parameter model (functional IMP method). The accuracy of these methods was validated by comparing rCBF values with those obtained by the standard method: the super-early microsphere method with continuous withdrawal of arterial blood. On analyzing rCBF in each flow range (0-0.25, 0.25-0.5, 0.5-0.75 and more than 0.75 ml/g/min), rCBF values obtained by both methods (a) and (c) showed significant correlations (p<0.01) with those obtained by the standard method in every range, but rCBF values obtained by method (b) did not significantly correlated in the high flow range (0.5-0.75 and more than 0.75 ml/g/min). Method (c) was found to be the most accurate, even though it needs two serial SPECT scans. When requiring one SPECT scan, method (a) was considered to be superior to method (b) because of its accuracy, especially in high flow regions loaded with acetazolamide. (author)

  1. Towards quantification of blood-flow changes during cognitive task activation using perfusion-based fMRI.

    Science.gov (United States)

    Mildner, Toralf; Zysset, Stefan; Trampel, Robert; Driesel, Wolfgang; Möller, Harald E

    2005-10-01

    Multi-slice perfusion-based functional magnetic resonance imaging (p-fMRI) is demonstrated with a color-word Stroop task as an established cognitive paradigm. Continuous arterial spin labeling (CASL) of the blood in the left common carotid artery was applied for all repetitions of the functional run in a quasi-continuous fashion, i.e., it was interrupted only during image acquisition. For comparison, blood oxygen level dependent (BOLD) contrast was detected using conventional gradient-recalled echo (GE) echo planar imaging (EPI). Positive activations in BOLD imaging appeared in p-fMRI as negative signal changes corresponding to an enhanced transport of inverted water spins into the region of interest, i.e., increased cerebral blood flow (CBF). Regional differences between the localization of activations and the sensitivity of p-fMRI and BOLD-fMRI were observed as, for example, in the inferior frontal sulcus and in the intraparietal sulcus. Quantification of CBF changes during cognitive task activation was performed on a multi-subject basis and yielded CBF increases of the order of 20-30%.

  2. Correlation of middle latency auditory evoked potentials and cerebral blood flow changes

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Seiichiro; Sugimoto, Akiko; Ohi, Takekazu; Matsukura, Shigeru; Watanabe, Katushi [Miyazaki Medical Coll., Kiyotake (Japan); Hoshi, Hiroaki

    1997-12-01

    The purpose of this study is to find the correlation between middle latency auditory evoked potentials (MLAEP) and sound activated single photon emission computed tomography (SPECT) studies. This study was performed on six normal right-handed volunteers with a mean age of 35.2{+-}7.6 years, using the split-dose technique. First, a SPECT study was performed on subjects in blinded, awake and silent states. After bilateral ears were stimulated with a click sound, MLAEP and a second SPECT study were performed. Subtraction of the first SPECT from the second SPECT revealed a statistically significant increase of cerebral blood flow (CBF) in the bilateral superior temporal region. Bilateral Na amplitudes of MLAEP had a statistically significant and good correlation with the percentages of CBF changes in the bilateral superior temporal region. The superior temporal cerebral blood flow activation can be expressed by electrophysiological activation. Moreover, correlation during the left Na components and left frontal and occipital lobe are discussed. (author)

  3. Effect of Korea red ginseng on cerebral blood flow and superoxide production

    Institute of Scientific and Technical Information of China (English)

    Cuk Seong KIM; Jin Bong PARK; Kwang-Jin KIM; Seok Jong CHANG; Sung-Woo RYOO; Byeong Hwa JEON

    2002-01-01

    AIM: To investigate the effects of Korea red ginseng (KRG) on the cerebral perfusion rate in the rats and the generation of superoxide anion in the endothelial cells. METHODS: The cerebral perfusion rate was measured using laser-doppler flowmetry before and after the administration of crude saponin (CS) and saponin-free fraction (SFF) of KRG in the anesthetized rats. The superoxide generation was measured by the method based on lucigeninenhanced chemiluminescence in the cultured endothelial cells. RESULTS: The relative cerebral perfusion rate (rCBF) was significantly increased by the intraperitoneal injection of CS (100 mg/kg) in the rats, but SFF had no effect on the rCBF. Chronic treatment with CS for 7 d significantly inhibited the decrease of forebrain cerebral blood flow induced by clamping both carotid arteries in the rats. Furthermore, CS (0.1 g/L) significantly suppressed NADPH-induced superoxide generation in the human umbilical vein endothelial cells (P<0.01).CONCLUSION: The present study demonstrated that crude saponin fraction of KRG enhanced cerebral blood flow in rats. Furthermore, crude saponin fraction of KRG abrogated the NADPH-driven superoxide generation in endothelial cells.

  4. Cerebral blood flow autoregulation in hypertension and effects of antihypertensive drugs

    DEFF Research Database (Denmark)

    Barry, David; Lassen, N A

    1984-01-01

    If antihypertensive treatment, especially emergency blood pressure lowering, is always to be safe, more thought should be given to autoregulation of cerebral blood in the hypertensive patient. This topic is reviewed in the present article, in the hypertensive patient. This topic is reviewed...... in the present article, particular emphasis being placed on the resetting of the lower limit of autoregulation to higher pressure in hypertension and the effects of acute administration of anti-hypertensive drugs on CBF and CBF-autoregulation....

  5. Probing Brain Oxygenation with Near Infrared spectroscopy, the Role of Carbon Dioxide and Blood Pressure

    CERN Document Server

    Gersten, Alexander

    2015-01-01

    The fundamentals of near infrared spectroscopy (NIRS) are reviewed. Among the major factors controlling the cerebral blood flow (CBF), the effect of PaCO2 is peculiar in that it violates autoregulatory CBF mechanisms and allows to explore the full range of the CBF. A simple physical model, with a four parameter formula, relating the CBF to PaCO2 is presented. It can be used to transform the fits of one animal to the fits of another one. It enable the use of rats data as monkeys data simply by rescaling the PaCO2 values and the CBF data. Controlled breathing can change the PaCO2. Experiments on human subjects relating the PaCO2 to rSO2, measured with brain oximeters, are presented. A simple model relating the mean blood pressure to CBF is worked out.

  6. Scaling of brain metabolism and blood flow in relation to capillary and neural scaling.

    Science.gov (United States)

    Karbowski, Jan

    2011-01-01

    Brain is one of the most energy demanding organs in mammals, and its total metabolic rate scales with brain volume raised to a power of around 5/6. This value is significantly higher than the more common exponent 3/4 relating whole body resting metabolism with body mass and several other physiological variables in animals and plants. This article investigates the reasons for brain allometric distinction on a level of its microvessels. Based on collected empirical data it is found that regional cerebral blood flow CBF across gray matter scales with cortical volume V as CBF ~ V(-1/6), brain capillary diameter increases as V(1/12), and density of capillary length decreases as V(-1/6). It is predicted that velocity of capillary blood is almost invariant (~V(ε)), capillary transit time scales as V(1/6), capillary length increases as V(1/6+ε), and capillary number as V(2/3-ε), where ε is typically a small correction for medium and large brains, due to blood viscosity dependence on capillary radius. It is shown that the amount of capillary length and blood flow per cortical neuron are essentially conserved across mammals. These results indicate that geometry and dynamics of global neuro-vascular coupling have a proportionate character. Moreover, cerebral metabolic, hemodynamic, and microvascular variables scale with allometric exponents that are simple multiples of 1/6, rather than 1/4, which suggests that brain metabolism is more similar to the metabolism of aerobic than resting body. Relation of these findings to brain functional imaging studies involving the link between cerebral metabolism and blood flow is also discussed.

  7. Scaling of brain metabolism and blood flow in relation to capillary and neural scaling.

    Directory of Open Access Journals (Sweden)

    Jan Karbowski

    Full Text Available Brain is one of the most energy demanding organs in mammals, and its total metabolic rate scales with brain volume raised to a power of around 5/6. This value is significantly higher than the more common exponent 3/4 relating whole body resting metabolism with body mass and several other physiological variables in animals and plants. This article investigates the reasons for brain allometric distinction on a level of its microvessels. Based on collected empirical data it is found that regional cerebral blood flow CBF across gray matter scales with cortical volume V as CBF ~ V(-1/6, brain capillary diameter increases as V(1/12, and density of capillary length decreases as V(-1/6. It is predicted that velocity of capillary blood is almost invariant (~V(ε, capillary transit time scales as V(1/6, capillary length increases as V(1/6+ε, and capillary number as V(2/3-ε, where ε is typically a small correction for medium and large brains, due to blood viscosity dependence on capillary radius. It is shown that the amount of capillary length and blood flow per cortical neuron are essentially conserved across mammals. These results indicate that geometry and dynamics of global neuro-vascular coupling have a proportionate character. Moreover, cerebral metabolic, hemodynamic, and microvascular variables scale with allometric exponents that are simple multiples of 1/6, rather than 1/4, which suggests that brain metabolism is more similar to the metabolism of aerobic than resting body. Relation of these findings to brain functional imaging studies involving the link between cerebral metabolism and blood flow is also discussed.

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

    Science.gov (United States)

    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.

  9. Regional cerebral blood flow in patients with transient ischemic attacks studied by Xenon-133 inhalation and emission tomography

    DEFF Research Database (Denmark)

    Vorstrup, S; Hemmingsen, R; Henriksen, L;

    1983-01-01

    with a spatial resolution of 1.7 cm. Based primarily on the clinical evidence and on the angiographical findings embolism was considered the pathogenetic factor in 10 cases, whereas chronic hemodynamic insufficiency rendered symptomatic by postural factors probably accounted for the symptoms in 4 patients....... Of the 14 patients, all studied days to weeks after the most recent TIA, four showed hypoperfused areas on the CBF-tomograms and with roughly the same location hypodense areas on CT-scanning, i.e. areas of complete infarction. However, an additional five patients showed reduction of CBF in areas...... with no abnormality on the CT-scan. The abnormal blood flow pattern was found to be unchanged after clinically successful reconstructive vascular surgery. This suggests the presence of irreversible ischemic tissue damage without gross emollition (incomplete infarction). It is concluded, that TIAs are often harmful...

  10. Regional cerebral blood flow before and after vascular surgery in patients with transient ischemic attacks with 133-xenon inhalation tomography

    DEFF Research Database (Denmark)

    Vorstrup, S; Hemmingsen, Ralf; Lindewald, H;

    1982-01-01

    with a spatial resolution of 1.7 cm. Based primarily on the clinical evidence and on the angiographical findings embolism was considered the pathogenetic factor in 10 cases, whereas chronic hemodynamic insufficiency rendered symptomatic by postural factors probably accounted for the symptoms in 4 patients....... Of the 14 patients, all studied days to weeks after the most recent TIA, four showed hypoperfused areas on the CBF-tomograms and with roughly the same location hypodense areas on CT-scanning, i.e. areas of complete infarction. However, an additional five patients showed reduction of CBF in areas...... with no abnormality on the CT-scan. The abnormal blood flow pattern was found to be unchanged after clinically successful reconstructive vascular surgery. This suggests the presence of irreversible ischemic tissue damage without gross emollition (incomplete infarction). It is concluded, that TIAs are often harmful...

  11. Cerebral blood flow during static exercise in humans

    DEFF Research Database (Denmark)

    Rogers, H B; Schroeder, T; Secher, N H

    1990-01-01

    voluntary contraction (MVC) and utilized alternate legs. CBF (measured by the 133Xe clearance technique) was expressed by a noncompartmental flow index (ISI). Heart rate and mean arterial pressure increased from resting values of 73 (55-80) beats/min and 88 (74-104) mmHg to 106 (86-138) beats/min and 124...... (102-146) mmHg, respectively (P less than 0.0005), during the contraction at 32% MVC. Arterial PCO2 and central venous pressure did not change. Corrected to the average resting PCO2, CBF during control was 55 (35-73) ml.100 g-1.min-1 and remained constant during contractions. Cerebral vascular...... resistance increased from 1.5 (1.0-2.2) to 2.4 (1.4-3.0) mmHg. 100 g.min.ml-1 (P less than 0.025) at 32% of MVC. There was no difference in CBF between the two hemispheres at rest or during exercise. In contrast to dynamic leg exercise, static leg exercise is not associated with an increase in global CBF...

  12. Pancreatic islet blood flow and its measurement.

    Science.gov (United States)

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future.

  13. Bone blood flow and metabolism in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo;

    2012-01-01

    Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

  14. The Physics of Coronary Blood Flow

    CERN Document Server

    Zamir, M

    2005-01-01

    Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

  15. Mechanics of blood flow in the microcirculation.

    Science.gov (United States)

    Secomb, T W

    1995-01-01

    The microcirculation in most tissues consists of an intricate network of very narrow tubes. In analyses of blood flow through the microcirculation, inertial effects can be neglected, but continuum models for blood cannot be assumed, since blood is a concentrated suspension of cells with dimensions comparable to vessel diameters. These cells strongly influence blood flow. About 45% of blood volume consists of red blood cells, whose key mechanical properties are known. A red cell has a fluid interior, surrounded by a flexible membrane, which strongly resists area changes, but bends and shears easily. White blood cells are comparable in size but much less numerous. They are less flexible than red cells and capable of active locomotion. Other suspended elements are much smaller than red cells: This review focuses on the mechanics of red cell motion in the microcirculation. Experimental and theoretical studies of blood flow in uniform tubes, bifurcations and networks are discussed. Comparisons between predicted and observed flows in networks imply that resistance to blood flow in living microvessels is higher than that in uniform tubes with corresponding diameters. Living microvessels have non-uniform geometries, and red cells must deform continually to traverse them. Theoretical results are presented implying that these transient deformations contribute to increased flow resistance in the microcirculation.

  16. Cerebral blood flow and metabolism during sleep

    DEFF Research Database (Denmark)

    Madsen, Peter Lund; Vorstrup, S

    1991-01-01

    investigations seem to identify site-specific changes in regional CBF and CMR during REM sleep. CBF and CMR are reflections of cerebral synaptic activity and the magnitude of reduction in these variables associated with deep sleep indicates that overall cerebral synaptic activity is reduced to approximately one......-half the level associated with wakefulness, while cerebral synaptic activity levels during REM sleep are similar to wakefulness. However, even though the new understanding of CBF and CMR during sleep provides significant and important information of the brain's mode of working during sleep, it does not at its...

  17. Treatment of Epilepsy with Bipolar Electro-coagulation: An Analysis of Cortical Blood Flow and Histological Change in Temporal Lobe

    Institute of Scientific and Technical Information of China (English)

    Zhi-Qiang Cui; Guo-Ming Luan; Jian Zhou; Feng Zhai; Yu-Guang Guan; Min Bao

    2015-01-01

    Background:Bipolar electro-coagulation has a reported efficacy in treating epilepsy involving functional cortex by pure electro-coagulation or combination with resection.However,the mechanisms of bipolar electro-coagulation are not completely known.We studied the acute cortical blood flow and histological changes after bipolar electro-coagulation in 24 patients with intractable temporal lobe epilepsy.Methods:Twenty-four patients were consecutively enrolled,and divided into three groups according to the date of admission.The regional cortical blood flow (rCBF),electrocorticography,the depth of cortex damage,and acute histological changes (H and E staining,neuronal staining and neurofilament (NF) staining) were analyzed before and after the operation.The t-test analysis was used to compare the rCBF before and after the operation.Results:The rCBF after coagulation was significantly reduced (P < 0.05).The spikes were significantly reduced after electro-coagulation.For the temporal cortex,the depth of cortical damage with output power of 2-9 W after electro-coagulation was 0.34 ± 0.03,0.48 ± 0.06,0.69 ± 0.06,0.84 ± 0.09,0.98 ± 0.08,1.10 ± 0.1 l,1.11 ± 0.09,and 1.22 ± 0.11 mm,respectively.Coagulation with output power of 4-5 W completely damaged the neurons and NF protein in the molecular layer,external granular layer,and external pyramidal layer.Conclusions:The electro-coagulation not only destroyed the neurons and NF protein,but also reduced the rCBF.We concluded that the injuries caused by electro-coagulation would prevent horizontal synchronization and spread of epileptic discharges,and partially destroy the epileptic focus.

  18. Noninvasive xenon-133 measurements of cerebral blood flow using stationary detectors compared with dynamic emission tomography

    DEFF Research Database (Denmark)

    Schroeder, T; Vorstrup, S; Lassen, N A;

    1986-01-01

    Repeated bedside measurements of CBF have been made possible by the recent development of a mobile unit with 10 stationary detectors using the intravenous xenon-133 method. To evaluate this technique, comparative CBF studies at rest and following the application of a cerebral vasodilatory stimulus...... (acetazolamide, 1 g i.v.) were performed with the mobile equipment and with xenon-133 single-photon emission inhalation tomography in patients with cerebrovascular disease. The CBF level and the flow response to acetazolamide as determined with the two methods were well correlated, although at low flow levels...

  19. Effect of clobenpropit on regional cerebral blood flow in rat hippocampus%改善大鼠海马局部脑血流的作用

    Institute of Scientific and Technical Information of China (English)

    陈忠

    2001-01-01

    AIM: The effect of clobenpropit on regional cerebral blood flow (rCBF) was investigated in the rat hippocampus. METHODS: rCBF was determined in the hippocampus by the hydrogen clearance method. The blood pressure was measured by a tail-cuff plethysmograph.RESULTS: Intracerebroventricular (icv) injection of clobenpropit (20, 50 μg), a representative H3-antagonist, dose-dependently and significantly increased rCBF in the hippocampus. The increase of rCBF induced by clobenpropit was enhanced by metoprine (1, 2 mg/kg),a selective histamine N-methyltransferase inhibitor; however, was antagonized by an H3-agonist, (R)-α-methylhistamine (5 μg), an H1-antagonist, mepyramine (5 - 10mg/kg), and an H2-antagonist, zolantidine (10 mg/kg). Clobenpropit caused no apparent effects on blood pressure even at a high dose of 50 μg. CONCLUSION: These results suggest that brain endogenous histamine may contribute to increase rCBF in the rat hippocampus via both the post-synaptic Hi-, H2-receptors and the pre-synaptic H3-receptor.%目的:研究和阐明clobenpropit对大鼠海马局部脑血流(rCBF)的作用机制.方法:采用氢清除法测定海马的部脑血流,并利用大鼠尾部体积描记器测定大鼠的血压.结果:侧脑室内注射clobenpropit ( 20,50μg)后,15-30 min,可剂量依赖性、显著地改善8-16月龄大鼠海马中的rCBF,而clobenpropit的作用可被氯苯氨啶加强.(R)-α-甲基组胺(5μg)则明显抑制clobenpropit的rCBF改善作用.另外,美吡拉敏(5, 10 mg/kg)和zolantidine ( 10 mg/kg)均可剂量依赖性地抑制clobenpropit提高rCBF的作用.Clobenpropit (5 - 50 μg )对血压不产生影响.结论:Clobenpropit可以改善8-16月龄大鼠海马中rCBF,其作用主要与组胺H1,H2和H3受体相关.

  20. Tomographic measurement of cerebral blood flow by the /sup 68/Ga-labelled-microsphere and continuous-C/sup 15/O/sub 2/-inhalation methods

    Energy Technology Data Exchange (ETDEWEB)

    Steinling, M.; Baron, J.C.; Maziere, B.; Loc' h, C.; Lasjaunias, P.; Canabis, E.A.; Guillon, B.

    1985-05-01

    The measurement of cerebral blood flow (CBF) by continuous C/sup 15/O/sub 2/ inhalation has only been validated previously by indirect experimental protocols. In the present study using baboons, these measurements were compared directly with those obtained by injection of /sup 68/Ga-labelled serum-albumin microspheres in the left cardiac ventricle. Using a modified labelling technique, no elution of /sup 68/Ga occurred in vivo. Both methods provided similar regional CBF values, which could be described by a significant linear correlation (CBFsub(CO2) = 0.82 CBFsub(microspheres)+5.7; P < 0.001). The validity of the labelled-microsphere-injection method was verified. The feasibility of stable in vivo labelling of /sup 68/Ga to serum-albumin microspheres provides a reference method for organ blood-flow measurements using positron-emission tomography.

  1. Tomographic measurement of cerebral blood flow by the /sup 68/Ga-labelled-microsphere and continuous-C/sup 15/O/sub 2/-inhalation methods

    Energy Technology Data Exchange (ETDEWEB)

    Steinling, M.; Baron, J.C.; Maziere, B.; Loc' h, C.; Lasjaunias, P.; Canabis, E.A.; Guillon, B.

    1985-07-01

    The measurement of cerebral blood flow (CBF) by continuous C/sup 15/O/sub 2/ inhalation has only been validated previously by indirect experimental protocols. In the present study using baboons, these measurements were compared directly with those obtained by injection of /sup 68/Ga-labelled serum-albumin microspheres in the left cardiac ventricle. Using a modified labelling technique, no elution of /sup 68/Ga occurred in vivo. Both methods provided similar regional CBF values, which could be described by a significant linear correlation (CBFsub(CO2)=0.82 CBFsub(microspheres)+5.7; P < 0.001). The validity of the labelled-microsphere-injection method was verified. The feasibility of stable in vivo labelling of /sup 68/Ga to serum-albumin microspheres provides a reference method for organ blood-flow measurements using positron-emission tomography.

  2. The change of cerebral blood flow after heart transplantation in congestive heart failure: a voxel-based and automatic VOl analysis of Tc-99m ECD SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Hong, I. K.; Kim, J. J.; Lee, C. H.; Lim, K. C.; Moon, D. H.; Rhu, J. S.; Kim, J. S. [Asan Medical Center, Seoul (Korea, Republic of)

    2007-07-01

    To investigate the change of global and regional cerebral blood flow after heart transplantation (HT) in congestive heart failure (CHF) patients. Twenty-one patients with CHF who underwent HT (45{+-}12 yrs, M/F=19/2) and 10 healthy volunteers (39{+-}13 yrs, M/F = 7/3) were prospectively included. All patients underwent echocardiography and radionuclide angiography including brain and aorta with brain SPECT which was performed after iv bolus injection of Tc-99m ECD (740MBq) before (175{+-}253 days) and after (129{+-}82 days) HT. Patients were divided into two groups according to the interval between HT and postoperative SPECT [early follow-up (f/u): <6 mo, n=14; late f/u: >6 mo, n=7]. Global CBF (gCBF) of bilateral hemispheres were calculated by Patlak graphical analysis. Absolute rCBF map was obtained from brain SPECT by Lassen's correction algorithm. Age-corrected voxel-based analysis using SPM2 and automatic VOl analysis were performed to assess the rCBF change. Cardiac ejection fraction of all patients improved after HT (20.8%{yields}64.0%). gCBF was reduced compared to normal before HT (35.7{+-}3.9 vs. 49.1{+-}3.0 ml/100g/min; p<0.001) and improved postoperatively (46.6{+-}5.4, p<0.001). The preoperative gCBFs of early and late f/u group were not different (34.6{+-}3.2 vs. 38.0{+-}4.4, p=0.149) but postoperative gCBF (43.9{+-}3.7) of late f/u group was higher than those (52.0{+-}4.0) of early f/u group (p<0.001). On voxel-based analysis, preoperative rCBF was reduced in entire brain but most severely in bilateral superior and inferior frontal cortex, supplementary motor area, precuneus and anterior cingulum, compared to normals (uncorrected p<0.001). After HT, rCBF of these areas improved more significantly in late f/u group than in early f/u group but still lower than normals. Global CBF was significantly reduced in CHF patients and improved after HT. rCBFs of the frontal cortex, precuneus and cingulum were most severely reduced and slowly improved after

  3. Low Residual CBF Variability in Alzheimer's Disease after Correction for CO(2) Effect

    DEFF Research Database (Denmark)

    Rodell, Anders Bertil; Aanerud, Joel; Braendgaard, Hans

    2012-01-01

    We tested the claim that inter-individual CBF variability in Alzheimer's disease (AD) is substantially reduced after correction for arterial carbon dioxide tension (PaCO(2)). Specifically, we tested whether the variability of CBF in brain of patients with AD differed significantly from brain of age...... for the differences of CO(2) tension, the patients with AD lost the inter-individual CBF variability that continued to characterize the HC subjects. The difference (¿K(1)) between the blood-brain clearances (K(1)) of water (the current measure of CBF) and oxygen (the current measure of oxygen clearance) was reduced...

  4. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    INTRODUCTION: Clinical work on the blood perfusion in skin and muscle flaps has suggested that some degree of blood flow autoregulation exists in such flaps. An autoregulatory mechanism would enable the flap to protect itself from changes in the perfusion pressure. The purpose of the present study...... was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......-type calcium channel blocker nimodipine and the vasodilator papaverine. MATERIAL AND METHODS: Pedicled flaps were raised in pigs. Flow in the pedicle was reduced by constriction of the feed artery (n=34). A transit time flow probe measured the effect on blood flow continuously. Following this, three different...

  5. Cerebral blood flow and metabolism for Broca's aphasia using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Toshiaki

    1987-12-01

    A total of 11 patients with Broca's aphasia (BA) underwent positron emission tomography (PET) with the purpose of investigating the responsible region and the symptomatic flow and metabolism thresholds for BA. Computed tomography (CT) was concurrently performed. In the group of 3 patients undergoing PET with C-11 glucose, both PET and CT provided abnormal findings in the region that is thought to be responsible for BA (Broca's area), including the cortex and subcortex in the anterior region to Sylvian fissure. The Broca's area in the remaining one was shown as low C-11 accumulation area on PET and as isodensity on CT. The second group, consisting of 8 BA patients and 30 control patients without BA, underwent PET using O-15 steady method. PET showed reduction of regional cerebral blood flow (rCBF) and oxygen metabolic rate (rCMRO/sub 2/) in the Broca's area in all BA patients. Computed tomography showed abnormal low density in the Broca's area in 3 patients, and abnormal findings in the basal ganglionic region and subcortex without evidence for abnormal low density in the Broca's area in the other 5 patients. Comparison of rCBF and rCMRO/sub 2/ in BA patients with those in control patients may show the symptomatic thresholds to be 20 - 27 ml100 gmin for rCBF and 2.0 ml100 gmin for rCMRO/sub 2/. (Namekawa, K.).

  6. Carbon dioxide and liver blood flow.

    Science.gov (United States)

    Dutton, R; Levitzky, M; Berkman, R

    1976-01-01

    This study was designed to determine blood flow to the liver during hypercapnia and combined hypercapnia-hypoxia with the portal vein and hepatic artery intact except for placement of an electromagnetic flow probe around these vessels. Twenty mongrel dogs weighing 30-45 kg were anesthetized with pentobarbital and flow probes and occluders were surgically implanted. Ten of these dogs were subjected to hypercapnia alone. During inspiration of 6% CO2 in room air, portal vein flow increased from 588 +/- 73 ml/min to 731 +/- 113 ml/min (p less than .05), while hepatic artery flow did not change significantly from its control mean of 221 +/- 38 ml/min. In the remaining dogs, inhalation of 6% O2 resulted in a reduction of portal blood flow within 30 min from 527 +/- 55 ml/min to 381 +/- 41 ml/min (p less than .01). Again, mean hepatic artery flow did not increase significantly above its control of 273 +/- 43 ml/min. Subsequent inhalation of 6% CO2 plus 6% O2 (combined hypercapniahypoxia) for 30 min in these same animals resulted in a significant increase of portal vein blood flow from 514 +/- 46 ml/min to 716 +/- 116 ml/min (p less than .05). Thus, hypercapnia alone increases total liver blood flow, primarily by an increase in portal vein flow. Hypoxia results in a decrease in portal vein flow. The superimposition of hypercapnia on hypoxia restores blood flow to a level close to that found with hypercapnia alone. Hypercapnia in the range of 63 +/- 4 mmHg PCO2 overwhelms the tendency toward a reduction of portal vein blood flow induced by an arterial PO2 of 42 +/- 5 mmHg in the presence of mild hypocapnia (PCO2 : 30.2 +/- 1 mmHg).

  7. Deciphering the neuronal circuitry controlling local blood flow in the cerebral cortex with optogenetics in PV::Cre transgenic mice

    Directory of Open Access Journals (Sweden)

    Alan eUrban

    2012-06-01

    Full Text Available Although it is know since more than a century that neuronal activity is coupled to blood supply regulation, the underlying pathways remains to be identified. In the brain, neuronal activation triggers a local increase of cerebral blood flow (CBF that is controlled by the neurogliovascular unit composed of terminals of neurons, astrocytes and blood vessel muscles. It is generally accepted that the regulation of the neurogliovascular unit is adjusted to local metabolic demand by local circuits. Today experimental data led us to realize that the regulatory mechanisms are more complex and that a neuronal system within the brain is devoted to the control of local brain blood flow. Recent optogenetic experiments combined with functional magnetic resonance imaging (fMRI have revealed that light stimulation of neurons expressing the calcium binding protein parvalbumin (PV is associated with positive blood oxygen level-dependent (BOLD signal in the corresponding barrel field but also with negative BOLD in the surrounding deeper area. Here, we demonstrate that in acute brain slices, ChR2-based photostimulation of PV containing neurons gives rise to an effective contraction of penetrating arterioles. These results support the neurogenic hypothesis of a complex distributed nervous system controlling the CBF.

  8. Quantitative analysis of the effects of donepezil on regional cerebral blood flow in Alzheimer's disease by using an automated program, 3DSRT

    Energy Technology Data Exchange (ETDEWEB)

    Tateno, Masaru [Sapporo Medical University, Department of Neuropsychiatry, Sapporo, Hokkaido (Japan); Kobayashi, Seiju; Utsumi, Kumiko [Sunagawa City Medical Center, Department of Psychiatry, Sunagawa (Japan); Morii, Hidetoshi; Fujii, Kazuki [Sunagawa City Medical Center, Department of Radiology, Sunagawa (Japan)

    2008-08-15

    Donepezil, an acetylcholinesterase inhibitor, has been reported to have an effect that improves cerebral blood flow (CBF) alongside its primary effect on memory function. The aim of this study was to investigate the effects of long-term, low-dose donepezil therapy on blood perfusion in Alzheimer's disease (AD) by using a fully automated regional CBF quantification program named 3DSRT. Fifteen subjects with mild to moderate AD according to NINCDS/ADRDA criteria underwent 99mTc-ethylcysteinate dimer (ECD) brain perfusion single photon emission computed tomography (SPECT) twice with an interval of 55.1{+-}11.0 weeks. The dose of donepezil was fixed at 5 mg/day following the induction period (3 mg/day) of 2 weeks. Clinical efficacy of donepezil was assessed by using the Mini-Mental State Examination (MMSE). The results of SPECT imaging under exactly identical conditions were analyzed by 3DSRT, which enables us to perform a very objective assessment. Despite a decrease of the MMSE score from 20.9{+-}4.7 to 18.7{+-}5.7, CBF was increased in almost all cerebral areas except the left temporal segment. The increase was statistically significant in the left callosomarginal, right central, and bilateral pericallosal and lenticular nucleus segments. Thus far, no direct cerebrovascular effects have been reported for donepezil. We hypothesize that these CBF-promoting effects of donepezil might be related to increased neuronal activity and enhanced connection of neurons. (orig.)

  9. [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].

    Science.gov (United States)

    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.

  10. Effect of intra-aortic balloon pump on coronary blood flow during different balloon cycles support: A computer study.

    Science.gov (United States)

    Aye, Thin Pa Pa; Htet, Zwe Lin; Singhavilai, Thamvarit; Naiyanetr, Phornphop

    2015-01-01

    Intra-aortic balloon pump (IABP) has been used in clinical treatment as a mechanical circulatory support device for patients with heart failure. A computer model is used to study the effect on coronary blood flow (CBF) with different balloon cycles under both normal and pathological conditions. The model of cardiovascular and IABP is developed by using MATLAB SIMULINK. The effect on coronary blood flow has been studied under both normal and pathological conditions using different balloon cycles (balloon off; 1:4; 1:2; 1:1). A pathological heart is implemented by reducing the left ventricular contractility. The result of this study shows that the rate of balloon cycles is related to the level of coronary blood flow.

  11. Normal CBF values by the ARG method using IMP SPECT. Comparison with a conventional microsphere model method

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Koyama, Masamichi; Kawashima, Ryuta; Ono, Shuichi; Fukuda, Hiroshi [Tohoku Univ., Sendai (Japan). Inst. of Development, Aging and Cancer; Ishii, Kiyoshi; Kinoshita, Toshifumi

    1996-02-01

    N-isopropyl-p[{sup 123}I]iodoamphetamine (IMP) has been used as a flow tracer for SPECT, and measurement of cerebral blood flow (CBF) using IMP has been performed by conventional microsphere model method (MS method). Recently, the ARG method for measuring CBF by using IMP with one SPECT scan and one point blood sampling has been developed. This method was based on two-compartment model. In the present study, normal CBF values were measured in 10 healthy male subjects (mean age{+-}S.D.: 29.8{+-}6.01, age range: 23-41) by ARG and MS methods. The mean CBF values ({+-}S.D.) for ARG method in which V{sub d} value was assumed to be 50 ml/ml were 41.7{+-}9.4, 31.1{+-}5.0, 40.7{+-}9.7, 41.5{+-}10.0, 38.2{+-}9.2, 39.0{+-}9.4, 41.9{+-}10.6, 38.7{+-}8.0 and 30.0{+-}7.7 ml/100 ml/min in the cerebellum, pons, thalamus, basal ganglia, frontal, temporal, parietal, occipital lobe cortex and centrum semiovale, respectively. The mean CBF values for the MS method were 46.8{+-}8.4, 37.5{+-}5.6, 45.8{+-}8.6, 46.5{+-}8.9, 43.7{+-}8.3, 44.4{+-}8.7, 46.8{+-}9.3, 44.3{+-}7.3 and 36.3{+-}8.1 ml/100 ml/min, respectively. The mean CBF values in the cerebral cortex region for ARG method were lower than those previously reported by PET. This would be caused by low first-pass extraction fraction of IMP compared with oxygen-15 labeled water. The mean CBF values for the MS method were higher than those for ARG method against previous studies. As reasons for this, errors in estimation of SPECT brain counts at 8 min in the MS method were considered. (author).

  12. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    Science.gov (United States)

    Mendrik, Adriënne M.; Vonken, Evert-jan; van Ginneken, Bram; de Jong, Hugo W.; Riordan, Alan; van Seeters, Tom; Smit, Ewoud J.; Viergever, Max A.; Prokop, Mathias

    2011-07-01

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  13. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    Energy Technology Data Exchange (ETDEWEB)

    Mendrik, Adrienne M; Van Ginneken, Bram; Viergever, Max A [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Vonken, Evert-jan; De Jong, Hugo W; Riordan, Alan; Van Seeters, Tom; Smit, Ewoud J; Prokop, Mathias, E-mail: a.m.mendrik@gmail.com [Radiology Department, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2011-07-07

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  14. Frequency encoding in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, Donald J; Sosnovtseva, Olga; Pavlov, Alexey N;

    2005-01-01

    With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...... of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation...... TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can...

  15. A New Computational Model for Neuro-Glio-Vascular Coupling: Astrocyte Activation Can Explain Cerebral Blood Flow Nonlinear Response to Interictal Events.

    Directory of Open Access Journals (Sweden)

    Solenna Blanchard

    Full Text Available Developing a clear understanding of the relationship between cerebral blood flow (CBF response and neuronal activity is of significant importance because CBF increase is essential to the health of neurons, for instance through oxygen supply. This relationship can be investigated by analyzing multimodal (fMRI, PET, laser Doppler… recordings. However, the important number of intermediate (non-observable variables involved in the underlying neurovascular coupling makes the discovery of mechanisms all the more difficult from the sole multimodal data. We present a new computational model developed at the population scale (voxel with physiologically relevant but simple equations to facilitate the interpretation of regional multimodal recordings. This model links neuronal activity to regional CBF dynamics through neuro-glio-vascular coupling. This coupling involves a population of glial cells called astrocytes via their role in neurotransmitter (glutamate and GABA recycling and their impact on neighboring vessels. In epilepsy, neuronal networks generate epileptiform discharges, leading to variations in astrocytic and CBF dynamics. In this study, we took advantage of these large variations in neuronal activity magnitude to test the capacity of our model to reproduce experimental data. We compared simulations from our model with isolated epileptiform events, which were obtained in vivo by simultaneous local field potential and laser Doppler recordings in rats after local bicuculline injection. We showed a predominant neuronal contribution for low level discharges and a significant astrocytic contribution for higher level discharges. Besides, neuronal contribution to CBF was linear while astrocytic contribution was nonlinear. Results thus indicate that the relationship between neuronal activity and CBF magnitudes can be nonlinear for isolated events and that this nonlinearity is due to astrocytic activity, highlighting the importance of astrocytes in

  16. Cerebral blood flow at 0.5 and 1.0 minimal alveolar concentrations of desflurane or sevoflurane compared with isoflurane in normoventilated pigs.

    Science.gov (United States)

    Holmström, A; Akeson, J

    2003-04-01

    Whether desflurane and sevoflurane have clinical advantages over isoflurane in neuroanesthesia is much debated. A porcine model was used for comparison of desflurane and sevoflurane with isoflurane with respect to their cerebrovascular effects. The minimal alveolar concentration (MAC) of each of the three agents was first determined in a standardized manner in six domestic juvenile pigs to enhance comparison reliability. Six other pigs were then anesthetized with isoflurane, desflurane, and sevoflurane, given in sequence to each pig in an even crosswise order with the first agent also used to maintain anesthesia during surgical preparation. Cerebral blood flow (CBF) was calculated from the clearance curve of intraarterially injected 133Xe. The mean arterial pressure (MAP) was invasively monitored. The estimated cerebrovascular resistance (CVRe) was calculated by dividing MAP with CBF, thereby approximating the cerebral perfusion pressure with MAP. For both MAC levels, the trend for CBF was desflurane > isoflurane > sevoflurane, and the trend for MAP and CVRe was sevoflurane > isoflurane > desflurane. Statistical comparison of desflurane and sevoflurane with isoflurane with respect to CBF and MAP revealed two statistically significant differences-namely, that CBF at 1.0 MAC desflurane was 17% higher than CBF at 1.0 MAC isoflurane (P =.0025) and that MAP at 1.0 MAC sevoflurane was 16% higher than MAP at 1.0 MAC isoflurane (P =.011). Consequently, in this study at normocapnia, these agents did not seem to differ much in their cerebral vasodilating effects at lower doses. At higher doses, however, desflurane, in contrast to sevoflurane, was found to induce more cerebral vasodilation than isoflurane.

  17. Regulation of blood flow by prostaglandins

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Risum, N;

    2004-01-01

    adaptation of connective tissues e.g. tendon. This review covers the role of PG for mediating tissue blood flow at rest and during increases in metabolic demand such as exercise and reactive hyperaemia. There is strong evidence that PGs contribute to elevate blood flow at rest and during reactive hyperaemia...... in a variety of tissues. Their role for regulating the large increases in muscle blood flow during exercise is less clear which may be explained by redundant mechanisms. Several interactions are known to exist between specific vasodilator substances, and therefore PGs can act in synergy with other substances...... and contribute to functional hyperaemia. Furthermore, there is evidence for differential, tissue-specific influences of PGs where their influence on blood flow during exercise may be profound....

  18. Blood flow and permeability in microvessels

    Science.gov (United States)

    Sugihara-Seki, Masako; Fu, Bingmei M.

    2005-07-01

    The mechanics of blood flow in microvessels and microvessel permeability are reviewed. In the first part, characteristics of blood flow in vivo and in vitro are described from a fluid-mechanical point of view, and mathematical models for blood flow in microvessels are presented. Possible causes of the increased flow resistance obtained in vivo compared to in vitro are examined, including the effects of irregularities of vessel lumen, the presence of endothelial surface glycocalyx and white blood cells. In the second part, the ultrastructural pathways and mechanisms whereby endothelial cells and the clefts between the cells modulate microvessel permeability to water and solutes are introduced. Previous and current models for microvessel permeability to water and solutes are reviewed. These models examine the role of structural components of interendothelial cleft, such as junction strands and surface glycocalyx, in the determination of water and solute transport across the microvessel walls. Transport models in the tissue space surrounding the microvessel are also described.

  19. Regional cerebral blood flow in acute stage with ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki; Iino, Katsuro; Kojima, Hisashi; Saito, Hitoshi; Suzuki, Mikio; Watanabe, Kazuo; Kato, Toshiro

    1987-05-01

    Single photon emission computed tomography (SPECT) with xenon-133 inhalation method was undertaken within 48 hr after the onset in 68 patients with ischemic cerebrovascular disease. The results for regional cerebral blood flow (rCBF) were compared with concurrently available computed tomography (CT) scans. In patients with cerebral infarction, SPECT detected ischemic lesions earlier than CT, with the detectability being 92 %. The area with a decreased blood flow, as seen on SPECT, was more extensive than the low density area on CT, with a concomitant decrease in blood flow in the contralateral cerebral hemisphere. Crossed cerebellar diaschisis was associated with stenosis of the internal carotid artery in 50 % (7/14), and with stenosis of the middle cerebral artery in 35 % (9/26). Abnormal SPECT findings were seen in 47 % (8/17) of the patients with transient ischemic attack (TIA). Five TIA patients had a decreased rCBF on SPECT, which was not provided by CT scans. On the contrary, small infarct lesions in the cerebral basal ganglia, as observed in 4 patients, was not detected by SPECT, but detected by CT. This may imply the limitations of SPECT in the detection of deep-seated lesions of the cerebrum. The results led to the conclusion that SPECT can be performed safely even in acute, seriously ill patients to know changes in rCBF because it is noninvasive and is capable of being repeated in a short time. (Namekawa, K.).

  20. Focal hyperemia followed by spreading oligemia and impaired activation of rCBF in classic migraine

    Energy Technology Data Exchange (ETDEWEB)

    Olesen, J.; Larsen, B.; Lauritzen, M.

    1981-04-01

    Regional cerebral blood flow (rCBF) was measured in 254 areas of a hemisphere with the xenon 133 intraarterial injection method. Six cases of classic migraine were followed from the normal state into the prodromal phase, and in 3 cases further into the headache phase. One patient with common migraine was similarly followed during his only classic attack. The attacks were initiated by focal hyperemia in 3 patients. During prodromes all patients displayed occipitoparietal rCBF reduction (oligemia), but in only 1 case did the reduction approach critical values. Oligemia gradually spread anteriorly in the course of 15 to 45 minutes. In 4 patients a global oligemia was observed. In 4 patients severe headache was present concomitantly with oligemia and with no sign of hyperemia or nonhomogeneous brain perfusion. The normal rCBF increase during cortical activity (hand movement, speech, and similar activities) was impaired in 6 patients. The results indicate that the vasospastic model of the migraine attack is too simplistic.

  1. Cerebral blood flow and metabolism during isoflurane-induced hypotension in patients subjected to surgery for cerebral aneurysms

    DEFF Research Database (Denmark)

    Madsen, J B; Cold, G E; Hansen, E S;

    1987-01-01

    Cerebral blood flow and cerebral metabolic rate for oxygen were measured during isoflurane-induced hypotension in 10 patients subjected to craniotomy for clipping of a cerebral aneurysm. Flow and metabolism were measured 5-13 days after the subarachnoid haemorrhage by a modification of the classi......Cerebral blood flow and cerebral metabolic rate for oxygen were measured during isoflurane-induced hypotension in 10 patients subjected to craniotomy for clipping of a cerebral aneurysm. Flow and metabolism were measured 5-13 days after the subarachnoid haemorrhage by a modification......). Controlled hypotension to an average MAP of 50-55 mm Hg was induced by increasing the dose of isoflurane, and maintained at an inspired concentration of 2.2 +/- 0.2%. This resulted in a significant decrease in CMRO2 (to 1.73 +/- 0.16 ml/100 g min-1), while CBF was unchanged. After the clipping...

  2. Effect of antihistamines, disodium cromoglycate (DSCG) or methysergide on post-irradiation cerebral blood flow and mean systemic arterial blood pressure in primates after 25 Gy, whole-body, gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cockerham, L.G.; Forcino, C.D. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)

    1995-06-01

    Exposure to ionizing radiation causes hypotension, cerebral ischemia and release of histamine (HA) and serotonin (5-HT). To investigate the relationship among these responses, rhesus monkeys (Macaca mulatta) received physiological saline (i.v.), disodium cromoglycate (DSCG), antihistamines (AH, mepyramine and cimetidine), or methysergide (METH), then were given 25 Gy whole-body irradiation. Monkeys receiving DSCG, AH or METH had higher post-irradiation mean arterial blood pressure (MBP) than saline-treated controls. Compared to levels in controls, post-irradiation hippocampal blood flow (rCBF) levels were higher in monkeys receiving DSCG, AH or METH. Treatment with the 5-HT{sub 2} receptor antagonist methysergide was the most effective in maintaining both rCBF and MBP after irradiation. Results support the hypothesis that the irradiation-induced cerebral ischemia and, to some extent, the hypotension is mediated by serotonin through 5-HT{sub 2} receptor sites. (author) 72 refs.

  3. Effect of disodium cromoglycate (DSCG) and antihistamines on post-irradiation cerebral blood flow and plasma levels of histamine and neurotensin

    Energy Technology Data Exchange (ETDEWEB)

    Cockerham, L.G.; Pautler, E.L.; Carraway, R.E.; Cochrane, D.E.; 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 visual cortical 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. Systemic arterial plasma histamine and neurotensin levels were determined preirradiation and postirradiation. Compared to control animals, the irradiated monkeys exhibited an abrupt decline in systemic blood pressure to 23% 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 cortical blood flow for the same animals showed a steady decrease to 29% of the preirradiation levels by 60-min postirradiation. Animals given the mast-cell stabilizer disodium cromoglycate and the antihistamines mepyramine and cimetidine before irradiation did not exhibit an abrupt decline in blood pressure but displayed a gradual decrease to a level 33% below preirradiation levels by 60 min postirradiation. Also, the treated, irradiated monkeys displayed rCBF values that were not significantly different from the nonirradiated controls. The plasma neurotensin levels in the irradiated animals, treated and untreated, indicated a nonsignificant postirradiation increase above control levels.

  4. 21 CFR 870.2120 - Extravascular blood flow probe.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Extravascular blood flow probe. 870.2120 Section... blood flow probe. (a) Identification. An extravascular blood flow probe is an extravascular ultrasonic or electromagnetic probe used in conjunction with a blood flowmeter to measure blood flow in...

  5. Cerebral blood flow during cardiopulmonary bypass in pediatric cardiac surgery: the role of transcranial Doppler – a systematic review of the literature

    Directory of Open Access Journals (Sweden)

    Sanders Stephen P

    2006-12-01

    Full Text Available Abstract Background Transcranial Doppler Ultrasound (TCD is a sensitive, real time tool for monitoring cerebral blood flow velocity (CBFV. This technique is fast, accurate, reproducible and noninvasive. In the setting of congenital heart surgery, TCD finds application in the evaluation of cerebral blood flow variations during cardiopulmonary bypass (CPB. Methodology We performed a search on human studies published on the MEDLINE using the keyword "trans cranial Doppler" crossed with "pediatric cardiac surgery" AND "cardio pulmonary by pass", OR deep hypothermic cardiac arrest", OR "neurological monitoring". Discussion Current scientific evidence suggests a good correlation between changes in cbral blood flow and mean cerebral artery (MCA blood flow velocity. The introduction of Doppler technology has allowed an accurate monitorization of cerebral blood flow (CBF during circulatory arrest and low-flow CPB. TCD has also been utilized in detecting cerebral emboli, improper cannulation or cross clamping of aortic arch vessels. Limitations of TCD routine utilization are represented by the need of a learning curve and some experience by the operators, as well as the need of implementing CBF informations with, for example, data on brain tissue oxygen delivery and consumption. Conclusion In this light, TCD plays an essential role in multimodal neurological monitorization during CPB (Near Infrared Spectroscopy, TCD, processed electro encephalography that, according to recent studies, can help to significantly improve neurological outcome after cardiac surgery in neonates and pediatric patients.

  6. Regional cerebral blood flow changes associated with transcranial magnetic stimulation in refractory depressed patients

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C. H.; Chung, Y. A.; Chae, J. H.; Oh, J. H.; Kim, S. H.; Sohn, H. S.; Chung, S. K. [The Catholic University of Korea, Seoul (Korea, Republic of)

    2005-07-01

    Imaging studies by repetitive transcranial magnetic stimulation (rTMS) demonstrates biological activities of the brain. The aim of this study was to investigate the patterns of regional cerebral blood flow (rCBF) after a series of therapeutic rTMS sessions. Nine patients with refractory depression who had not been responsive to appropriate pharmacotherapy over 1 year were randomly assigned to daily 1 Hz right-sided rTMS or 20 Hz left-sided rTMS sessions for over 3 weeks. Baseline and 3-week post-rTMS treatment SPECT images were obtained 40 minutes after intravenous injection of approximately 740925 MBq of Tc-99m ECD using a multi-detector scanner (ECAM plus; Siemens, Erlangen, Germany) equipped with a low-energy, fan-beam collimator. All patients showed a good clinical outcome. Statistically significant common increase in rCBF patterns was found in the fusiform gyrus of left temporal lobe, left hippocampus, left superior parietal lobule, superior frontal gyrus of right frontal lobe, right lateral globus pallidus and cingulated gyrus of both limbic lobes. And in the fusiform gyrus of left occipital lobe and middle frontal gyrus of right frontal lobe decreased uptake was seen compared to controls. Low-frequency rTMS on the right prefrontal cortex and high-frequency rTMS on the left prefrontal cortex for 3 weeks as an add-on regimen have increased activity in specific brain regions in patients with treatment refractory depression. Therapeutic TMS seems to influence distinct cortical regions, as well as different pathways, affecting rCBF in a homogeneous manner that is probably region dependent and illness related.

  7. Effect of disodium cromoglycate (DSCG) and antihistamines on postirradiation cerebral blood flow and plasma levels of histamine and neurotensin

    Energy Technology Data Exchange (ETDEWEB)

    Cockerham, L.G.; Pautler, E.L.; Carraway, R.E.; Cochrane, D.E.; Hampton, J.D.

    1988-02-01

    In an attempt to elucidate mechanisms underlying the irradiation-induced decrease in regional cerebral blood flow (rCBF) in primates, hippocampal and visual cortical 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. Systemic arterial plasma histamine and neurotensin levels were determined preirradiation and postirradiation. Compared to control animals, the irradiated monkeys exhibited an abrupt decline in systemic blood pressure to 23% 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 cortical blood flow for the same animals showed a steady decrease to 29% of the preirradiation levels by 60 min postirradiation. Animals given the mast cell stabilizer disodium cromoglycate and the antihistamines mepyramine and cimetidine before irradiation did not exhibit an abrupt decline in blood pressure but displayed a gradual decrease to a level 33% below preirradiation levels by 60 min postirradiation. Also, the treated, irradiated monkeys displayed rCBF values that were not significantly different from the nonirradiated controls. The plasma neurotensin levels in the irradiated animals, treated and untreated, indicated a nonsignificant postirradiation increase above control levels. However, the postirradiation plasma histamine levels in both irradiated groups showed an increase of approximately 1600% above the preirradiation levels and the postirradiation control levels.

  8. Cerebral O2 metabolism and cerebral blood flow in humans during deep and rapid-eye-movement sleep

    DEFF Research Database (Denmark)

    Madsen, P L; Schmidt, J F; Wildschiødtz, Gordon

    1991-01-01

    It could be expected that the various stages of sleep were reflected in variation of the overall level of cerebral activity and thereby in the magnitude of cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF). The elusive nature of sleep imposes major methodological restriction...... associated with light anesthesia. During REM sleep (dream sleep) CMRO2 was practically the same as in the awake state. Changes in CBF paralleled changes in CMRO2 during both deep and REM sleep....... on examination of this question. We have now measured CBF and CMRO2 in young healthy volunteers using the Kety-Schmidt technique with 133Xe as the inert gas. Measurements were performed during wakefulness, deep sleep (stage 3/4), and rapid-eye-movement (REM) sleep as verified by standard polysomnography....... Contrary to the only previous study in humans, which reported an insignificant 3% reduction in CMRO2 during sleep, we found a deep-sleep-associated statistically highly significant 25% decrease in CMRO2, a magnitude of depression according with studies of glucose uptake and reaching levels otherwise...

  9. A Dietary Treatment Improves Cerebral Blood Flow and Brain Connectivity in Aging apoE4 Mice

    Directory of Open Access Journals (Sweden)

    Maximilian Wiesmann

    2016-01-01

    Full Text Available APOE ε4 (apoE4 polymorphism is the main genetic determinant of sporadic Alzheimer’s disease (AD. A dietary approach (Fortasyn including docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium has been proposed for dietary management of AD. We hypothesize that the diet could inhibit AD-like pathologies in apoE4 mice, specifically cerebrovascular and connectivity impairment. Moreover, we evaluated the diet effect on cerebral blood flow (CBF, functional connectivity (FC, gray/white matter integrity, and postsynaptic density in aging apoE4 mice. At 10–12 months, apoE4 mice did not display prominent pathological differences compared to wild-type (WT mice. However, 16–18-month-old apoE4 mice revealed reduced CBF and accelerated synaptic loss. The diet increased cortical CBF and amount of synapses and improved white matter integrity and FC in both aging apoE4 and WT mice. We demonstrated that protective mechanisms on vascular and synapse health are enhanced by Fortasyn, independent of apoE genotype. We further showed the efficacy of a multimodal translational approach, including advanced MR neuroimaging, to study dietary intervention on brain structure and function in aging.

  10. A Dietary Treatment Improves Cerebral Blood Flow and Brain Connectivity in Aging apoE4 Mice.

    Science.gov (United States)

    Wiesmann, Maximilian; Zerbi, Valerio; Jansen, Diane; Haast, Roy; Lütjohann, Dieter; Broersen, Laus M; Heerschap, Arend; Kiliaan, Amanda J

    2016-01-01

    APOE ε4 (apoE4) polymorphism is the main genetic determinant of sporadic Alzheimer's disease (AD). A dietary approach (Fortasyn) including docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium has been proposed for dietary management of AD. We hypothesize that the diet could inhibit AD-like pathologies in apoE4 mice, specifically cerebrovascular and connectivity impairment. Moreover, we evaluated the diet effect on cerebral blood flow (CBF), functional connectivity (FC), gray/white matter integrity, and postsynaptic density in aging apoE4 mice. At 10-12 months, apoE4 mice did not display prominent pathological differences compared to wild-type (WT) mice. However, 16-18-month-old apoE4 mice revealed reduced CBF and accelerated synaptic loss. The diet increased cortical CBF and amount of synapses and improved white matter integrity and FC in both aging apoE4 and WT mice. We demonstrated that protective mechanisms on vascular and synapse health are enhanced by Fortasyn, independent of apoE genotype. We further showed the efficacy of a multimodal translational approach, including advanced MR neuroimaging, to study dietary intervention on brain structure and function in aging.

  11. Nimodipine pretreatment improves cerebral blood flow and reduces brain edema in conscious rats subjected to focal cerebral ischemia.

    Science.gov (United States)

    Jacewicz, M; Brint, S; Tanabe, J; Wang, X J; Pulsinelli, W A

    1990-11-01

    The effect of nimodipine pretreatment on CBF and brain edema was studied in conscious rats subjected to 2.5 h of focal cortical ischemia. An infusion of nimodipine (2 micrograms/kg/min i.v.) or its vehicle, polyethylene glycol 400, was begun 2 h before the ischemic interval and was continued throughout the survival period. Under brief halothane anesthesia, the animals' right middle cerebral and common carotid arteries were permanently occluded, and 2.5 h later, they underwent a quantitative CBF study ([14C]iodoantipyrine autoradiography followed by Quantimet 970 image analysis). Nimodipine treatment improved blood flow to the middle cerebral artery territory without evidence of a "vascular steal" and reduced the volume of the ischemic core (cortex with CBF of less than 25 ml/100 g/min) and accompanying edema by approximately 50% when compared with controls (p = 0.006 and 0.0004, respectively). Mild hypotension induced by nimodipine did not aggravate the ischemic insult. The ischemic core volumes, however, were 50-75% smaller than the 24-h infarct volumes generated in a similar paradigm that demonstrated 20-30% infarct reduction with continuous nimodipine treatment. These results suggest that nimodipine pretreatment attenuates the severity of early focal cerebral ischemia, but that with persistent ischemia, cortex surrounding the ischemic core undergoes progressive infarction and the early benefit of nimodipine treatment is only partly preserved.

  12. Meditation effects on cognitive function and cerebral blood flow in subjects with memory loss: a preliminary study.

    Science.gov (United States)

    Newberg, Andrew B; Wintering, Nancy; Khalsa, Dharma S; Roggenkamp, Hannah; Waldman, Mark R

    2010-01-01

    This preliminary study determined if subjects with memory loss problems demonstrate changes in memory and cerebral blood flow (CBF) after a simple 8-week meditation program. Fourteen subjects with memory problems had an IV inserted and were injected with 250 MBq of Tc-99m ECD while listening to a neutral stimulus CD. They then underwent a pre-program baseline SPECT scan. Then subjects were guided through their first meditation session with a CD, during which they received an injection of 925 MBq ECD, and underwent a pre-program meditation scan. Subjects completed an 8-week meditation program and underwent the same scanning protocol resulting in a post-program baseline and meditation scan. A region of interest (ROI) template obtained counts in each ROI normalized to whole brain to provide a CBF ratio. Baseline and meditation scans and neuropsychological testing were compared before and after the program. The meditation program resulted in significant increases (pmemory showed improvements after training. This preliminary study evaluated whether an 8-week meditation program resulted in improvements in neuropsychological function and differences in CBF in subjects with memory loss. While the findings are encouraging, there are a number of limitations that can be addressed in future studies with more participants and more detailed analyses.

  13. Regional cerebral blood flow as assessed by principal component analysis and {sup 99m}Tc-HMPAO SPET in healthy subjects at rest: normal distribution and effect of age and gender

    Energy Technology Data Exchange (ETDEWEB)

    Pagani, M. [Inst. of Neurobiology and Molecular Medicine, CNR, Rome (Italy); Dept. of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Salmaso, D. [Inst. of Psychology, CNR, Rome (Italy); Jonsson, C.; Hatherly, R.; Larsson, S.A. [Dept. of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Jacobsson, H. [Dept. of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden); Waegner, A. [Dept. of Clinical Neuroscience, Karolinska Institutet, Stockholm (Sweden); Dept. of Clinical Neuroscience, Karolinska Hospital, Stockholm (Sweden)

    2002-01-01

    The increasing implementation of standardisation techniques in brain research and clinical diagnosis has highlighted the importance of reliable baseline data from normal control subjects for inter-subject analysis. In this context, knowledge of the regional cerebral blood flow (rCBF) distribution in normal ageing is a factor of the utmost importance. In the present study, rCBF was investigated in 50 healthy volunteers (25 men, 25 women), aged 31-78 years, who were examined at rest by means of single-photon emission tomography (SPET) using technetium-99m d,l-hexamethylpropylene amine oxime (HMPAO). After normalising the CBF data, 27 left and 27 right volumes of interest (VOIs) were selected and automatically outlined by standardisation software (computerised brain atlas). The heavy load of flow data thus obtained was reduced in number and grouped in factors by means of principal component analysis (PCA). PCA extracted 12 components explaining 81% of the variance and including the vast majority of cortical and subcortical regions. Analysis of variance and regression analyses were performed for rCBF, age and gender before PCA was applied and subsequently for each single extracted factor. There was a significantly higher CBF on the right side than on the left side (P<0.001). In the overall analysis, a significant decrease was found in CBF (P=0.05) with increasing age, and this decrease was particularly evident in the left hemisphere (P=0.006). When gender was specifically analysed, CBF was found to decrease significantly with increasing age in females (P=0.037) but not in males. Furthermore, a significant decrease in rCBF with increasing age was found in the brain vertex (P=0.05), left frontotemporal cortex (P=0.012) and temporocingulate cortex (P=0.003). By contrast, relative rCBF in central structures increased with age (P=0.001). The ability of standardisation software and PCA to identify functionally connected brain regions might contribute to a better

  14. Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs

    DEFF Research Database (Denmark)

    Sandgaard, N C F; Andersen, J L; Holstein-Rathlou, N-H;

    2002-01-01

    We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven...... arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range ... of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta....

  15. Cerebral blood flow and cerebrovascular reserve capacity: estimation by dynamic magnetic resonance imaging.

    Science.gov (United States)

    Schreiber, W G; Gückel, F; Stritzke, P; Schmiedek, P; Schwartz, A; Brix, G

    1998-10-01

    We have developed a new method for estimation of regional CBF (rCBF) and cerebrovascular reserve capacity on a pixel-by-pixel basis by means of dynamic magnetic resonance imaging (MRI). Thirteen healthy volunteers, 8 patients with occlusion and/or high grade stenosis of the internal carotid artery (ICA), and 2 patients with acute stroke underwent dynamic susceptibility-weighted contrast enhanced MRI. Using principles of indicator dilution theory and deconvolution analysis, maps of rCBF, regional cerebral blood volume, and of the mean transit time (MTT) were calculated. In patients with ICA occlusion/stenosis, cerebrovascular reserve capacity was assessed by the rCBF increase after acetazolamide stimulation. Mean gray and white matter rCBF values in normals were 67.1 and 23.7 mL x 100 g(-1) x min(-1), respectively. Before acetazolamide stimulation, six of eight patients with ICA occlusions showed decreased rCBF values; and in seven patients increased MTT values were observed in tissue ipsilateral to the occlusion. After acetazolamide stimulation, decreased cerebrovascular reserve capacity was observed in five of eight patients with ICA occlusion. In acute stroke, rCBF in the central core of ischemia was less than 8 mL x 100 g(-1) x min(-1). In peri-infarct tissue, rCBF and MTT were higher than in unaffected tissue but rCBF was normal. Dynamic MRI provides important clinical information on the hemodynamic state of brain tissue in patients with occlusive cerebrovascular disease or acute stroke.

  16. SU-D-18C-02: Feasibility of Using a Short ASL Scan for Calibrating Cerebral Blood Flow Obtained From DSC-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P; Chang, T; Huang, K; Yeh, C; Chien, C; Wai, Y; Lee, T; Liu, H [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan County, Taiwan (R.O.C.). (China)

    2014-06-01

    Purpose: This study aimed to evaluate the feasibility of using a short arterial spin labeling (ASL) scan for calibrating the dynamic susceptibility contrast- (DSC-) MRI in a group of patients with internal carotid artery stenosis. Methods: Six patients with unilateral ICA stenosis enrolled in the study on a 3T clinical MRI scanner. The ASL-cerebral blood flow (-CBF) maps were calculated by averaging different number of dynamic points (N=1-45) acquired by using a Q2TIPS sequence. For DSC perfusion analysis, arterial input function was selected to derive the relative cerebral blood flow (rCBF) map and the delay (Tmax) map. Patient-specific CF was calculated from the mean ASL- and DSC-CBF obtained from three different masks: (1)Tmax< 3s, (2)combined gray matter mask with mask 1, (3)mask 2 with large vessels removed. One CF value was created for each number of averages by using each of the three masks for calibrating the DSC-CBF map. The CF value of the largest number of averages (NL=45) was used to determine the acceptable range(< 10%, <15%, and <20%) of CF values corresponding to the minimally acceptable number of average (NS) for each patient. Results: Comparing DSC CBF maps corrected by CF values of NL (CBFL) in ACA, MCA and PCA territories, all masks resulted in smaller CBF on the ipsilateral side than the contralateral side of the MCA territory(p<.05). The values obtained from mask 1 were significantly different than the mask 3(p<.05). Using mask 3, the medium values of Ns were 4(<10%), 2(<15%) and 2(<20%), with the worst case scenario (maximum Ns) of 25, 4, and 4, respectively. Conclusion: This study found that reliable calibration of DSC-CBF can be achieved from a short pulsed ASL scan. We suggested use a mask based on the Tmax threshold, the inclusion of gray matter only and the exclusion of large vessels for performing the calibration.

  17. Focal cerebral ischemia measured by the intra-arterial 133xenon method. Limitations of 2-dimensional blood flow measurements

    DEFF Research Database (Denmark)

    Skyhøj Olsen, T; Larsen, B; Bech Skriver, E;

    1981-01-01

    of 133 xenon (rCBF), 2) the initial distribution of isotope during the first 5 sec and 3) the cumulated counts recorded during 15 min. Compton scatter and the "look through phenomenon" were responsible for the majority of counts recorded from the infarcted areas and the blood flow recorded was found...... to be grossly overestimated and much more influenced by the blood flow in the surroundings than in the ischemic area itself. However, using the 3 approaches, infarcted areas were always disclosed by our equipment. It is concluded that 2-dimensional isotope technique is not reliable for quantifying focal...... with infarcts involving cortical surface structures were included in the study. Eleven such patients were found among 43 consecutive patients with completed stroke, all investigated with CT-scan. The blood supply to the infarcted areas was evaluated using 3 different approaches: 1) The first minute washout...

  18. Focal cerebral ischemia measured by the intra-arterial 133xenon method. Limitations of 2-dimensional blood flow measurements

    DEFF Research Database (Denmark)

    Skyhøj Olsen, T; Larsen, B; Bech Skriver, E;

    1981-01-01

    with infarcts involving cortical surface structures were included in the study. Eleven such patients were found among 43 consecutive patients with completed stroke, all investigated with CT-scan. The blood supply to the infarcted areas was evaluated using 3 different approaches: 1) The first minute washout...... of 133 xenon (rCBF), 2) the initial distribution of isotope during the first 5 sec and 3) the cumulated counts recorded during 15 min. Compton scatter and the "look through phenomenon" were responsible for the majority of counts recorded from the infarcted areas and the blood flow recorded was found...... to be grossly overestimated and much more influenced by the blood flow in the surroundings than in the ischemic area itself. However, using the 3 approaches, infarcted areas were always disclosed by our equipment. It is concluded that 2-dimensional isotope technique is not reliable for quantifying focal...

  19. pCO(2) and pH regulation of cerebral blood flow.

    Science.gov (United States)

    Yoon, Seonghun; Zuccarello, Mario; Rapoport, Robert M

    2012-01-01

    CO(2) serves as one of the fundamental regulators of cerebral blood flow (CBF). It is widely considered that this regulation occurs through pCO(2)-driven changes in pH of the cerebral spinal fluid (CSF), with elevated and lowered pH causing direct relaxation and contraction of the smooth muscle, respectively. However, some findings also suggest that pCO(2) acts independently of and/or in conjunction with altered pH. This action may be due to a direct effect of CSF pCO(2) on the smooth muscle as well as on the endothelium, nerves, and astrocytes. Findings may also point to an action of arterial pCO(2) on the endothelium to regulate smooth muscle contractility. Thus, the effects of pH and pCO(2) may be influenced by the absence/presence of different cell types in the various experimental preparations. Results may also be influenced by experimental parameters including myogenic tone as well as solutions containing significantly altered HCO(3) (-) concentrations, i.e., solutions routinely employed to differentiate the effects of pH from pCO(2). In sum, it appears that pCO(2), independently and in conjunction with pH, may regulate CBF.

  20. Flavor-Enhanced Modulation of Cerebral Blood Flow during Gum Chewing.

    Directory of Open Access Journals (Sweden)

    Yoko Hasegawa

    Full Text Available Flavor perception, the integration of taste and odor, is a critical factor in eating behavior. It remains unclear how such sensory signals influence the human brain systems that execute the eating behavior.WE TESTED CEREBRAL BLOOD FLOW (CBF IN THE FRONTAL LOBES BILATERALLY WHILE SUBJECTS CHEWED THREE TYPES OF GUM WITH DIFFERENT COMBINATIONS OF TASTE AND ODOR: no taste/no odor gum (C-gum, sweet taste/no odor gum (T-gum, and sweet taste/lemon odor gum (TO-gum. Simultaneous recordings of transcranial Doppler ultrasound (TCD and near infrared spectrometer (NIRS were used to measure CBF during gum chewing in 25 healthy volunteers. Bilateral masseter muscle activity was also monitored.We found that subjects could discriminate the type of gum without prior information. Subjects rated the TO-gum as the most flavorful gum and the C-gum as the least flavorful. Analysis of masseter muscle activity indicated that masticatory motor output during gum chewing was not affected by taste and odor. The TCD/NIRS measurements revealed significantly higher hemodynamic signals when subjects chewed the TO-gum compared to when they chewed the C-gum and T-gum.These data suggest that taste and odor can influence brain activation during chewing in sensory, cognitive, and motivational processes rather than in motor control.

  1. The evaluation of regional cerebral blood flow in the chronic alcohol abuse patients

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. A.; Kim, D. J.; Oh, J. H.; Kim, C. H.; Kim, S. H.; Sohn, H. S.; Chung, S. K. [The Catholic University of Korea, Seoul (Korea, Republic of)

    2005-07-01

    The use of alcohol is increasingly prevalent in our country and remains associated with innumerable social and economic problems. In addition, brain abnormalities have been proved by means of neuroimaging techniques not only in the first days of withdrawal, but also months after the last use of the substance in the patients. The purpose of the present study was to investigate patterns of the regional cerebral blood flow (rCBF) in alcoholic dementia. Six patients (all men; 44-67 years, mean age = 57.5 years) who fulfilled DSM-IV criteria for alcoholic dementia were enrolled in the study. RCBF measurements of resting state using Tc-99m ethyl cysteinate dimmer (ECD) SPECT were performed. The SPECT image was obtained 40 minutes after intravenous injection of 1110 MBq of Tc-99m ECD using a dual-head gamma camera (ECAM plus; Siemens, Erlangen, Germany). The normalized SPECT data from the alcoholic dementia group were compared with those from 12 healthy subjects. Alcoholic dementia patients showed significant decrement of rCBF in the left thalamus, superior frontal gyrus of left frontal lobe, left insula, postcentral gyrus of left parietal lobe, parahippocapal gyrus of left limbic lobe, right caudate, and cingulate gyrus of right limbic lobe than age-matched healthy subjects. Despite the small number of patients examined, the study supports the belief that patients with alcohol induced cognitive dysfunction have the neuro pathophysiology as those with classical alcoholic dementia.

  2. An implantable blood pressure and flow transmitter.

    Science.gov (United States)

    Rader, R. D.; Meehan, J. P.; Henriksen, J. K. C.

    1973-01-01

    A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months. Pressure is detected by a miniature intravascular transducer and flow is detected by an extravascular interferometric ultrasonic technique. Both pressure and flow are calibrated prior to implanting. The pressure calibration can be checked after the implanting by cannulation; flow calibration can be verified only at the end of the experiment by determining the voltage output from the implanted sensing system as a function of several measured flow rates. The utility of this device has been established by its use in investigating canine renal circulation during exercise, emotional encounters, administration of drugs, and application of accelerative forces.

  3. l-Citrulline ameliorates cerebral blood flow during cortical spreading depression in rats: Involvement of nitric oxide- and prostanoids-mediated pathway.

    Science.gov (United States)

    Kurauchi, Yuki; Mokudai, Koichi; Mori, Asami; Sakamoto, Kenji; Nakahara, Tsutomu; Morita, Masahiko; Kamimura, Ayako; Ishii, Kunio

    2017-02-17

    l-Citrulline is a potent precursor of l-arginine, and exerts beneficial effect on cardiovascular system via nitric oxide (NO) production. Migraine is one of the most popular neurovascular disorder, and imbalance of cerebral blood flow (CBF) observed in cortical spreading depression (CSD) contributes to the mechanism of migraine aura. Here, we investigated the effect of l-citrulline on cardiovascular changes to KCl-induced CSD. in rats. Intravenous injection of l-citrulline prevented the decrease in CBF, monitored by laser Doppler flowmetry, without affecting mean arterial pressure and heart rate during CSD. Moreover, l-citrulline attenuated propagation velocity of CSD induced by KCl. The effect of l-citrulline on CBF change was prevented by l-NAME, an inhibitor of NO synthase, but not by indomethacin, an inhibitor of cyclooxygenase. On the other hand, attenuation effect of l-citrulline on CSD propagation velocity was prevented not only by l-NAME but also by indomethacin. In addition, propagation velocity of CSD was attenuated by intravenous injection of NOR3, a NO donor, which was diminished by ODQ, an inhibitor of soluble guanylyl cyclase. These results suggest that NO/cyclic GMP- and prostanoids-mediated pathway differently contribute to the effect of l-citrulline on the maintenance of CBF.

  4. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: I. Theory, error analysis, and stereologic comparison

    DEFF Research Database (Denmark)

    Lida, H; Law, I; Pakkenberg, B

    2000-01-01

    formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...... onto the PET images in which regional CBF values and the water perfusable tissue fraction for the cortical gray matter tissue (hence the volume of gray matter) were estimated. After the PET study, the animals were killed and stereologic analysis was performed to assess the gray matter mass...

  5. BLOOD FLOW AND MACROMOLECULAR TRANSPORT IN CURVED BLOOD VESSELS

    Institute of Scientific and Technical Information of China (English)

    WEI Lan; WEN Gong-bi; TAN Wen-chang

    2006-01-01

    A numerical analysis of the steady/pulsatile flow and macromolecular (such as LDL and Albumin) transport in curved blood vessels was carried out. The computational results predict that the vortex of the secondary flow is time-dependent in the aortic arch.The concentration of macromolecule concentrates at the region of sharp curve, and the wall concentration at the outer part is higher than that at the inner part. Atherosclerosis and thrombosis are prone to develop in such regions with sharp flow.

  6. Laser Doppler flowmeter study on regional cerebral blood flow in early stage after standard superficial temporal artery-middle cerebral artery bypass surgery for moyamoya disease

    Institute of Scientific and Technical Information of China (English)

    GESANG Dun-zhu; ZHANG Dong; ZHAO Ji-zong; WANG Shuo; ZHAO Yuan-li; WANG Rong; SUN Jian-jun; MENG Ze

    2009-01-01

    Background Standard superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery is an effective treatment for moyamoya disease, but recent evidence suggests that postoperative cerebral hyperperfusion can occur. In this study, the trendline of changes in regional cerebral blood flow (rCBF) after surgery were continually monitored near the site of anastomosis in order to investigate both the efficacy of the procedure for improving rCBF and the possible riskof hyperperfusion.Methods Standard STA-MCA bypass surgery was performed on 13 patients, rCBF was measured continually using laser Doppler flowmetry (LDF) until the 5th day after the operation with the LDF probe implanted adjacent to the area of the anastomosis. The trendline of rCBF changes postoperatively was recorded for the analysis performed using SPSS 13.0.Results The baseline LDF value of cortical rCBF was (84.68±14.39) perfusion unit (PU), which was linear relative to absolute perfusion volume before anastomosis and (88.90±11.26) PU immediately after anastomosis (P >0.05). The value changed significantly from before to after anastomosis (P 0.05).Conclusions STA-MCA anastomosis improves the cerebral blood supply significantly in the early stage after surgery,however, the risk of symptomatic hyperperfusion may exist, which may possibly occur on the 1st day and 5th day after surgery. A LDF is useful for postoperative monitoring for both the efficacy of bypass and possible risk of neurologic deterioration or bleeding from hyperperfusion.

  7. A novel method of combining blood oxygenation and blood flow sensitive magnetic resonance imaging techniques to measure the cerebral blood flow and oxygen metabolism responses to an unknown neural stimulus.

    Directory of Open Access Journals (Sweden)

    Aaron B Simon

    Full Text Available Simultaneous implementation of magnetic resonance imaging methods for Arterial Spin Labeling (ASL and Blood Oxygenation Level Dependent (BOLD imaging makes it possible to quantitatively measure the changes in cerebral blood flow (CBF and cerebral oxygen metabolism (CMRO(2 that occur in response to neural stimuli. To date, however, the range of neural stimuli amenable to quantitative analysis is limited to those that may be presented in a simple block or event related design such that measurements may be repeated and averaged to improve precision. Here we examined the feasibility of using the relationship between cerebral blood flow and the BOLD signal to improve dynamic estimates of blood flow fluctuations as well as to estimate metabolic-hemodynamic coupling under conditions where a stimulus pattern is unknown. We found that by combining the information contained in simultaneously acquired BOLD and ASL signals through a method we term BOLD Constrained Perfusion (BCP estimation, we could significantly improve the precision of our estimates of the hemodynamic response to a visual stimulus and, under the conditions of a calibrated BOLD experiment, accurately determine the ratio of the oxygen metabolic response to the hemodynamic response. Importantly we were able to accomplish this without utilizing a priori knowledge of the temporal nature of the neural stimulus, suggesting that BOLD Constrained Perfusion estimation may make it feasible to quantitatively study the cerebral metabolic and hemodynamic responses to more natural stimuli that cannot be easily repeated or averaged.

  8. A novel method of combining blood oxygenation and blood flow sensitive magnetic resonance imaging techniques to measure the cerebral blood flow and oxygen metabolism responses to an unknown neural stimulus.

    Science.gov (United States)

    Simon, Aaron B; Griffeth, Valerie E M; Wong, Eric C; Buxton, Richard B

    2013-01-01

    Simultaneous implementation of magnetic resonance imaging methods for Arterial Spin Labeling (ASL) and Blood Oxygenation Level Dependent (BOLD) imaging makes it possible to quantitatively measure the changes in cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO(2)) that occur in response to neural stimuli. To date, however, the range of neural stimuli amenable to quantitative analysis is limited to those that may be presented in a simple block or event related design such that measurements may be repeated and averaged to improve precision. Here we examined the feasibility of using the relationship between cerebral blood flow and the BOLD signal to improve dynamic estimates of blood flow fluctuations as well as to estimate metabolic-hemodynamic coupling under conditions where a stimulus pattern is unknown. We found that by combining the information contained in simultaneously acquired BOLD and ASL signals through a method we term BOLD Constrained Perfusion (BCP) estimation, we could significantly improve the precision of our estimates of the hemodynamic response to a visual stimulus and, under the conditions of a calibrated BOLD experiment, accurately determine the ratio of the oxygen metabolic response to the hemodynamic response. Importantly we were able to accomplish this without utilizing a priori knowledge of the temporal nature of the neural stimulus, suggesting that BOLD Constrained Perfusion estimation may make it feasible to quantitatively study the cerebral metabolic and hemodynamic responses to more natural stimuli that cannot be easily repeated or averaged.

  9. Effects of regional cerebral blood flow perfusion on learning and memory function and its molecular mechanism in rats

    Institute of Scientific and Technical Information of China (English)

    Cunli Xu; Wenhua Wu; Lingbin Kong

    2016-01-01

    Objective:To study the effects of regional cerebral blood flow (rCBF) perfusion on learning and memory function in special brain areas and its molecular mechanism in rat. Methods: Sixty-four adult male healthy Sprague-Dawley (SD) rats were randomly divided into two groups: Afalse operation group and an operation group. The false operation group was randomly divided into four subgroups (A0, B0, C0, and D0) and the operation group was randomly divided into four subgroups (A, B, C, and D), with eight rats in each subgroup. The operation group underwent bilateral common carotid artery permanent ligation, while the other group only underwent a skin incision without the bilateral common carotid artery permanent ligation. Learning memory function of rats in each subgroup was measured using a Y-maze at 4 h, 8 h, 24 h, and 3 days after surgery. The rCBF in the right frontal lobe and hippocampus was detected using the Periflux PF model laser Doppler flowmetry and c-fos, c-jun, Bcl-2, and Bax protein expression in the right frontal lobe and hippocampus was measured using immunohistochemistry. Results: The rCBF in the right frontal lobule division and right hippocampus division was significantly lower in the operation group than in the false operation group (P Conclusions:rCBF decrease can impair learning and memory function in rats, which may be related to the increased expression of c-fos, c-jun, Bcl-2, and Bax proteins in the frontal cortex and hippocampus.

  10. Cerebral small-resistance artery structure and cerebral blood flow in normotensive subjects and hypertensive patients

    Energy Technology Data Exchange (ETDEWEB)

    De Ciuceis, Carolina; Porteri, Enzo; Rizzoni, Damiano; Boari, Gianluca E.M.; Rosei, Enrico Agabiti [University of Brescia, Clinica Medica, Department of Clinical and Experimental Sciences, Brescia (Italy); Cornali, Claudio; Mardighian, Dikran; Fontanella, Marco M. [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Pinardi, Chiara [Spedali Civili, Medical Physics Unit, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Rodella, Luigi F.; Rezzani, Rita [University of Brescia, Section of Anatomy, Department of Clinical and Experimental Sciences, Brescia (Italy); Gasparotti, Roberto [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy)

    2014-12-15

    The aim of this study was to prospectively investigate whether the structure of cerebral small-resistance arteries is related to cerebral perfusion parameters as measured with dynamic susceptibility-weighted contrast magnetic resonance imaging (DSC-MRI) in a selected cohort of hypertensive and normotensive patients. Ten hypertensive and 10 normotensive patients were included in the study. All patients underwent neurosurgical intervention for an intracranial tumor and were investigated with DSC-MRI at 1.5 T. Cerebral small-resistance arteries were dissected from a small portion of morphologically normal cerebral tissue and mounted on an isometric myograph for the measurement of the media-to-lumen (M/L) ratio. A quantitative assessment of cerebral blood flow (CBF) and volume (CBV) was performed with a region-of-interest approach. Correlation coefficients were calculated for normally distributed variables. The institutional review board approved the study, and informed consent was obtained from all patients. Compared with normotensive subjects, hypertensive patients had significantly lower regional CBF (mL/100 g/min) in the cortical grey matter (55.63 ± 1.90 vs 58.37 ± 2.19, p < 0.05), basal ganglia (53.34 ± 4.39 vs 58.22. ± 4.33, p < 0.05), thalami (50.65 ± 3.23 vs 57.56 ± 4.45, p < 0.01), subcortical white matter (19.32 ± 2.54 vs 22.24 ± 1.9, p < 0.05), greater M/L ratio (0.099 ± 0.013 vs 0.085 ± 0.012, p < 0.05), and lower microvessel density (1.66 ± 0.67 vs 2.52 ± 1.28, p < 0.05). A statistically significant negative correlation was observed between M/L ratio of cerebral arteries and CBF in the cortical grey matter (r = -0.516, p < 0.05), basal ganglia (r = -0.521, p < 0.05), thalami (r = -0.527 p < 0.05), and subcortical white matter (r = -0.612, p < 0.01). Our results indicate that microvascular structure might play a role in controlling CBF, with possible clinical consequences. (orig.)

  11. Arterial Transit Time Mapping Obtained by Pulsed Continuous 3D ASL Imaging with Multiple Post-Label Delay Acquisitions: Comparative Study with PET-CBF in Patients with Chronic Occlusive Cerebrovascular Disease.

    Science.gov (United States)

    Tsujikawa, Tetsuya; Kimura, Hirohiko; Matsuda, Tsuyoshi; Fujiwara, Yasuhiro; Isozaki, Makoto; Kikuta, Ken-Ichiro; Okazawa, Hidehiko

    2016-01-01

    Arterial transit time (ATT) is most crucial for measuring absolute cerebral blood flow (CBF) by arterial spin labeling (ASL), a noninvasive magnetic resonance (MR) perfusion assessment technique, in patients with chronic occlusive cerebrovascular disease. We validated ASL-CBF and ASL-ATT maps calculated by pulsed continuous ASL (pCASL) with multiple post-label delay acquisitions in patients with occlusive cerebrovascular disease. Fifteen patients underwent MR scans, including pCASL, and positron emission tomography (PET) scans with 15O-water to obtain PET-CBF. MR acquisitions with different post-label delays (1.0, 1.5, 2.0, 2.5 and 3.0 sec) were also obtained for ATT correction. The theoretical framework of 2-compartmental model (2CM) was also used for the delay compensation. ASL-CBF and ASL-ATT were calculated based on the proposed 2CM, and the effect on the CBF values and the ATT correction characteristics were discussed. Linear regression analyses were performed both on pixel-by-pixel and region-of-interest bases in the middle cerebral artery (MCA) territory. There were significant correlations between ASL-CBF and PET-CBF both for voxel values (r = 0.74 ± 0.08, slope: 0.87 ± 0.22, intercept: 6.1 ± 4.9) and for the MCA territorial comparison in both affected (R2 = 0.67, y = 0.83x + 6.3) and contralateral sides (R2 = 0.66, y = 0.74x + 6.3). ASL-ATTs in the affected side were significantly longer than those in the contralateral side (1.51 ± 0.41 sec and 1.12 ± 0.30 sec, respectively, p <0.0005). CBF measurement using pCASL with delay compensation was feasible and fairly accurate even in altered hemodynamic states.

  12. Cerebral blood flow in the neonate.

    Science.gov (United States)

    Vutskits, Laszlo

    2014-01-01

    Ensuring adequate oxygenation of the developing brain is the cornerstone of neonatal critical care. Despite decades of clinical research dedicated to this issue of paramount importance, our knowledge and understanding regarding the physiology and pathophysiology of neonatal cerebral blood flow are still rudimentary. This review primarily focuses on currently available human clinical and experimental data on cerebral blood flow and autoregulation in the preterm and term infant. Limitations of systemic blood pressure values as surrogates for monitoring adequate cerebral oxygen delivery are discussed. Particular emphasis is placed on the high interindividual variability in cerebral blood flow values, vasoreactivity, and autoregulatory thresholds making the applications of normative values highly questionable. Technical and ethical difficulties to conduct such trials leave us with a near complete lack of knowledge on how pharmacological and surgical interventions impact on cerebral autoregulation. The ensemble of these works argues for the necessity of highly individualized care by taking advantage of continuous bedside monitoring of cerebral circulation. They also point to the urgent need for further studies addressing the exciting but difficult issue of cerebral blood flow autoregulation in the neonate.

  13. Blood flow characteristics in the aortic arch

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Mihaiescu, Mihai; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2012-11-01

    The purpose with this study is to investigate the flow characteristics of blood in the aortic arch. Cardiovascular diseases are associated with specific locations in the arterial tree. Considering atherogenesis, it is claimed that the Wall Shear Stress (WSS) along with its temporal and spatial gradients play an important role in the development of the disease. The WSS is determined by the local flow characteristics, that in turn depends on the geometry as well as the rheological properties of blood. In this numerical work, the time dependent fluid flow during the entire cardiac cycle is fully resolved. The Quemada model is applied to account for the non-Newtonian properties of blood, an empirical model valid for different Red Blood Cell loading. Data obtained through Cardiac Magnetic Resonance Imaging have been used in order to reconstruct geometries of the the aortic arch. Here, three different geometries are studied out of which two display malformations that can be found in patients having the genetic disorder Turner's syndrome. The simulations show a highly complex flow with regions of secondary flow that is enhanced for the diseased aortas. The financial support from the Swedish Research Council (VR) and the Sweden-America Foundation is gratefully acknowledged.

  14. Delayed reflow of an ischemic infarct after spontaneous thrombolysis studied by CBF tomography using SPECT and Tc-99m HMPAO

    DEFF Research Database (Denmark)

    Companioni, J M; Lassen, N A; Tfelt-Hansen, P

    1991-01-01

    A patient with a large ischemic infarct in the left middle cerebral artery territory was studied six times in the acute/subacute phase by cerebral blood flow (CBF) tomography using Tc-99m-HMPAO. The SPECT instrument used was a brain dedicated highly sensitive four-camera system (TOMOMATIC 232) th...... of the occlusion with flows reaching levels above that of the opposite non-affected side ("Luxury Perfusion"). The delayed reflow implies, that SPECT may not constitute a reliable tool for evaluating the success or failure of thrombolytic treatment in ischemic stroke....

  15. Transcutaneous measurement of volume blood flow

    Science.gov (United States)

    Daigle, R. E.; Mcleod, F. D.; Miller, C. W.; Histand, M. B.; Wells, M. K.

    1974-01-01

    Blood flow velocity measurements, using Doppler velocimeter, are described. The ability to measure blood velocity using ultrasound is derived from the Doppler effect; the change in frequency which occurs when sound is reflected or transmitted from a moving target. When ultrasound of the appropriate frequency is transmitted through a moving blood stream, the blood cells act as point scatterers of ultrasonic energy. If this scattered ultrasonic energy is detected, it is found to be shifted in frequency according to the velocity of the blood cells, nu, the frequency of the incident sound, f sub o, the speed of sound in the medium, c, and the angle between the sound beam and the velocity vector, o. The relation describing this effect is known as the Doppler equation. Delta f = 2 f sub o x nu x cos alpha/c. The theoretical and experimental methods are evaluated.

  16. Changes in Regional Cerebral Blood Flow with Cognitive Behavioral Therapy in the Treatment of Panic Disorder

    Energy Technology Data Exchange (ETDEWEB)

    Won, K. S.; Jun, S. K.; Kim, J. B.; Jang, E. J. [College of Medicine, Univ. of Kyemyoung, Taegu (Korea, Republic of)

    2003-07-01

    This study attempted to prospectively investigate changes in regional cerebral blood flow (rCBF) on SPECT and clinical response to cognitive behavioral therapy (CBT) in patients with panic disorder with (PDA) and without (PD) agoraphobia. Using 99mTc-ECD brain SPECT, we assessed brain perfusion in 5 out patients at rest before and after CBT. The subjects received 12 weekly sessions of CBT. Subjects were assessed by Agoraphobic Cognitions Questionnaire, Body Sensations Questionnaire, Beck Anxiety Inventory, Anxiety Sensitivity Index, Beck Depression Inventory-II, Panic Disorder Severity Scale (PDSS) and clinical global improvement (CGI) scale measurement were used as outcome measures. Patients were considered responders to CBT if they are much or very much improved on CGI scale and have a PDSS score at least 30% below their baseline. The scans were statistically analyzed by using statistical parametric mapping (SPM99). The baseline scans were compared to the post-CBT scans by using the statistics option multi subject, different conditions. Of 5 subjects 4 were male, 3 diagnosed PDA, and 4 on anti-anxiety medication. All of the subjects were classified as CBT responders. Their mean pretreatment and posttreatment PDSS were 17.4 (SD=8.2) and 4.2 (SD=3.1), respectively. The results of SPM analysis showed a significant decrease in blood flow after CBT in the thalamus bilaterally and right middle frontal gyrus (Brodmann's area 6). All results were thresholded at an uncorrected p<0.001 (for voxel height) and a corrected p<0.04 (for spatial extent). These preliminary data suggest that SPM analysis of 99mTc-ECD brain SPECT can reveal the change of rCBF in patient with panic disorder before and after CBT and the CBT effect may be associated with limbic and thalamic networks. However this study was a short trial with small number of subjects. Further studies with larger patient cohorts are needed.

  17. Cerebral blood flow and oxygen metabolism in patients with dementia of the Alzheimer's type by position emission tomography using 0-15 steady state technique

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Shizuki; Kitamura, Shin; Ujike, Takashi; Terashi, Akiro; Iio, Masaaki.

    1988-07-01

    In 12 patients with dementia of the Alzheimer's type (DAT) and 5 age-matched healthy subjects, regional cerebral blood flow (rCBF), oxygen extraction fraction (rOEF), and cerebral oxygen consumption (rCMRO/sub 2/) were determined using positron emission tomography (PET) with 0-15 labeled CO/sub 2/ and O/sub 2/ inhalation method. There was a significant reduction in CMRO/sub 2/ of the temporal cortex in the group of mild DAT compared with the control group. In the group of moderate DAT, CBF of the temporal cortex and CMRO/sub 2/ of the temporal and parietal cortices were significantly reduced. The group of severe DAT showed a significantly reduced CBF and CMRO/sub 2/ in the frontal cortex, and a relatively spared occipital cortex in all stages. The results indicated that metabolic reduction in the temporal cortex first occurs, and that metabolic dysfunction in the parietal and frontal cortices results in blood flow reduction and deterioration of DAT. Right/left metabolic asymmetry in the temporal and parietal cortices was correlated with language and visuospatial functions. (Namekawa, K).

  18. Time-course changes of regional cerebral blood flow by SPECT with N-isopropyl-p-( sup 123 I)-iodoamphetamine in childhood partial seizures

    Energy Technology Data Exchange (ETDEWEB)

    Michihiro, Narumi; Ariizumi, Motomizu; Shiihara, Hiroaki; Egami, Yuriko; Saga, Takeshi (Dokkyo Univ. School of Medicine, Koshigaya, Saitama (Japan). Koshigaya Hospital)

    1992-07-01

    Single photon emission computed tomography (SPECT) with N-isopropyl-p-({sup 123}I)-iodoamphetamine was performed twice at different times in 18 children suffering from partial seizures to evaluate the time-course changes of the hemodynamics in the focal region. Comparison of the 2 SPECT images revealed that a decreased regional cerebral blood flow (CBF) in the first was normalized in 4 cases (22.2%) and contracted in 7 cases (38.9%). The region of decreased blood flow in the second was contralateral to that in the first in 1 case (5.6%) and unchanged in 6 cases (33.3%). Most of the normalized and contracted cases were those in which clinical seizures disappeared and the EEG findings were normalized. In these cases which responded to treatment, the decreased regional CBF was also found to be improved. Repeated SPECT appears to be useful for evaluating the therapeutic efficacy. On the other hand, most of the underchanged cases were those in which clinical seizures were frequent or uncontrolled, or which persistently showed the abnormalities in their EG. SPECT was considered to reflect well the conditions of the epileptic foci. These results indicate that repeated SPECT for observing the time-course changes of the regional CBF represents a useful technique which can be applied in evaluating the therapeutic efficacy or deciding the time to discontinue treatment and for pathogenetic elucidation of the epileptic foci. (author).

  19. Blood flow dynamics in the snake spectacle.

    Science.gov (United States)

    van Doorn, Kevin; Sivak, Jacob G

    2013-11-15

    The eyes of snakes are shielded beneath a layer of transparent integument referred to as the 'reptilian spectacle'. Well adapted to vision by virtue of its optical transparency, it nevertheless retains one characteristic of the integument that would otherwise prove detrimental to vision: its vascularity. Given the potential consequence of spectacle blood vessels on visual clarity, one might expect adaptations to have evolved that mitigate their negative impact. Earlier research demonstrated an adaptation to their spatial layout in only one species to reduce the vessels' density in the region serving the foveal and binocular visual fields. Here, we present a study of spectacle blood flow dynamics and provide evidence of a mechanism to mitigate the spectacle blood vessels' deleterious effect on vision by regulation of blood flow through them. It was found that when snakes are at rest and undisturbed, spectacle vessels undergo cycles of dilation and constriction, such that the majority of the time the vessels are fully constricted, effectively removing them from the visual field. When snakes are presented with a visual threat, spectacle vessels constrict and remain constricted for longer periods than occur during the resting cycles, thus guaranteeing the best possible visual capabilities in times of need. Finally, during the snakes' renewal phase when they are generating a new stratum corneum, the resting cycle is abolished, spectacle vessels remain dilated and blood flow remains strong and continuous. The significance of these findings in terms of the visual capabilities and physiology of snakes is discussed.

  20. Effects of aortic irregularities on blood flow.

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2016-04-01

    Anatomic aortic anomalies are seen in many medical conditions and are known to cause disturbances in blood flow. Turner syndrome (TS) is a genetic disorder occurring only in females where cardiovascular anomalies, particularly of the aorta, are frequently encountered. In this study, numerical simulations are applied to investigate the flow characteristics in four TS patient- related aortic arches (a normal geometry, dilatation, coarctation and elongation of the transverse aorta). The Quemada viscosity model was applied to account for the non-Newtonian behavior of blood. The blood is treated as a mixture consisting of water and red blood cells (RBC) where the RBCs are modeled as a convected scalar. The results show clear geometry effects where the flow structures and RBC distribution are significantly different between the aortas. Transitional flow is observed as a jet is formed due to a constriction in the descending aorta for the coarctation case. RBC dilution is found to vary between the aortas, influencing the WSS. Moreover, the local variations in RBC volume fraction may induce large viscosity variations, stressing the importance of accounting for the non-Newtonian effects.

  1. Ergot alkaloids decrease rumen epithelial blood flow

    Science.gov (United States)

    Two experiments were conducted to determine if ergot alkaloids affect blood flow to the absorptive surface of the rumen of steers. Steers (n=8 total) were pair-fed alfalfa cubes at 1.5× NEM and received ground endophyte-infected tall fescue seed (E+) or endophyte-free tall fescue seed (E-) via rumen...

  2. Frequency encoding in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

    2005-01-01

    With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...

  3. Improvement in regional CBF by L-serine contributes to its neuroprotective effect in rats after focal cerebral ischemia.

    Directory of Open Access Journals (Sweden)

    Tao-Jie Ren

    Full Text Available To investigate the mechanisms underlying the neuroprotective effect of L-serine, permanent focal cerebral ischemia was induced by occlusion of the middle cerebral artery while monitoring cerebral blood flow (CBF. Rats were divided into control and L-serine-treated groups after middle cerebral artery occlusion. The neurological deficit score and brain infarct volume were assessed. Nissl staining was used to quantify the cortical injury. L-serine and D-serine levels in the ischemic cortex were analyzed with high performance liquid chromatography. We found that L-serine treatment: 1 reduced the neurological deficit score, infarct volume and cortical neuron loss in a dose-dependent manner; 2 improved CBF in the cortex, and this effect was inhibited in the presence of apamin plus charybdotoxin while the alleviation of both neurological deficit score and infarct volume was blocked; and 3 increased the amount of L-serine and D-serine in the cortex, and inhibition of the conversion of L-serine into D-serine by aminooxyacetic acid did not affect the reduction of neurological deficit score and infarct volume by L-serine. In conclusion, improvement in regional CBF by L-serine may contribute to its neuroprotective effect on the ischemic brain, potentially through vasodilation which is mediated by the small- and intermediate-conductance Ca(2+-activated K(+ channels on the cerebral blood vessel endothelium.

  4. Kinetic and metabolic considerations in the use of (I-125) HIPDM as a tracer for quantitative measurement of regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Lucignani, G.; Nehlig, A.; Blasberg, R.; Patlak, C.S.; Anderson, L.; Kung, H.F.; Fieschi, C.; Fazio, F.; Sokoloff, L.

    1984-01-01

    The kinetics of cerebral uptake and the metabolism of radioactive iodine labeled HIPDM (N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-(I-125)iodobenzyl) -1,3-propanediamine)(I-125)HIPDM were studied in vivo in male adult Sprague-Dawley rats in order to evaluate the potential usefulness of this compound for quantitative measurement of regional cerebral blood flow (rCBF). The first pass extraction fraction of (I-125)HIPDM in brain was found to be about 80%. The arterial concentration of unmetabolized (I-125)HIPDM following an i.v. pulse drops rapidly and represents only 30% of the blood sample total radioactivity at 60 minutes, whereas 92% of the radioactivity in brain tissue at the same time is in unaltered (I-125)HIPDM. The rate constant for (I-125)HIPDM transport across the blood-brain barrier (BBB) was calculated on the basis of a distribution model in which bi-directional exchange of the tracer between brain tissue and vascular space is assumed. A kinetic model and an operational equation have been derived for determination of rCBF with this molecule. The model and equation take into account the three following factors: (a) incomplete first pass extraction; (b) HIPDM metabolism; (c) bi-directional flux of tracer across the BBB. The observations suggest that this molecule might be of potential usefulness for rCBF measurements with single photon emission tomography, provided that all these factors are evaluated in man.

  5. Dose reduction in dynamic perfusion CT of the brain: effects of the scan frequency on measurements of cerebral blood flow, cerebral blood volume, and mean transit time

    Energy Technology Data Exchange (ETDEWEB)

    Wiesmann, Martin [University of Munich, Department of Neuroradiology, Muenchen (Germany); Klinikum der Universitaet Muenchen - Grosshadern, Abteilung fuer Neuroradiologie, Muenchen (Germany); Berg, Scott; Stoeckelhuber, B.M. [University of Luebeck, Department of Radiology, Luebeck (Germany); Bohner, G.; Klingebiel, R. [University Medicine Berlin, Department of Neuroradiology, Charite, Berlin (Germany); Schoepf, V.; Yousry, I.; Linn, J. [University of Munich, Department of Neuroradiology, Muenchen (Germany); Missler, U. [Evangelisches Krankenhaus Duisburg-Nord, Department of Neuroradiology, Duisburg (Germany)

    2008-12-15

    The influence of the frequency of computed tomography (CT) image acquistion on the diagnostic quality of dynamic perfusion CT (PCT) studies of the brain was investigated. Eight patients with clinically suspected acute ischemia of one hemisphere underwent PCT, performed on average 3.4 h after the onset of symptoms. Sixty consecutive images per slice were obtained with individual CT images obtained at a temporal resolution of two images per second. Eight additional data sets were reconstructed with temporal resolutions ranging from one image per second to one image per 5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) measurements were performed in identical regions of interest. Two neuroradiologists evaluated the PCT images visually to identify areas of abnormal perfusion. Perfusion images created up to a temporal resolution of one image per 3 s were rated to be diagnostically equal to the original data. Even at one image per 4 s, all areas of infarction were identified. Quantitative differences of CBF, CBV and MTT measurements were {<=}10% up to one image per 3 s. For PCT of the brain, temporal resolution can be reduced to one image per 3 s without significant compromise in image quality. This significantly reduces the radiation dose of the patient. (orig.)

  6. Integrated Measurements of Electrical Activity, Oxygen Tension, Blood Flow, and Ca2+ -Signaling in Rodents In Vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Thomsen, Kirsten; Lauritzen, Martin

    2014-01-01

    in rodent preparation. We also describe methods for recording of cerebral blood flow (CBF), tissue partial pressure of oxygen (tpO2), and cytosolic calcium transients. We finally give examples where electrophysiology, blood flow, metabolism, and calcium transients have been studied together.......In order to assess perfusion and metabolic responses in relation to neural function we need to know the cellular signaling network, which types of neurons and astrocytes are involved, and the timing of their activation. We here present the basic electrophysiological indicators of neuronal function......, short description of the methods commonly used for recording of electrophysiological signals, examples of data analysis and limitations of the methods. This chapter describes the origin of the extracellularly recorded electrical signal, with special regard to the EEG, local field potentials, and spikes...

  7. Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex

    Science.gov (United States)

    Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.

    2013-06-01

    Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects.

  8. Comparison of CBF1, CBF2, CBF3 and CBF4 expression in some grapevine cultivars and species under cold stress

    Science.gov (United States)

    Karimi, Maryam; Ebadi, Ali; Mousavi, Seyed Amir; Salami, Seyed Alireza; Zarei, Abdolkarim

    2015-01-01

    Grapevine, an important horticultural crop in the world, is moderately tolerant to cold conditions and is subjected to the cold injuries at different regions. So studies on different aspects of tolerance mechanism to unexpected cold of late spring as well as winter freezing seems necessary about this vine. For this reason, study on genes responsible for acquiring cold tolerance is very important. Transcription factors are among regulatory proteins that are responsible for cold acclimation. In this research work, expression levels of CBF1, CBF2, CBF3, and CBF4 transcription factors were studied on two cvs of Vitis vinifera (“Khalili-Danedar” and “Shahroodi”) as well as one Vitis riparia at different times after treating at 4 °C. Results showed that two vinifera cultivars, “Khalili-Danedar” and “Shahroodi”, had similar trend for each transcription factor. Gene expression increased at the beginning of cold stress and then decreased. Expression of these TF started some minutes (CBF1) after cold treatment and continued for several hours (CBF2), even till the tenth day (CBF4). All together V. riparia which is endemic to the cold regions behaved stronger and showed higher expression for all studied transcription factors. Among two V. vinifera cultivars, “Khalili-Danedar” showed significantly higher expression compared with “Shahroodi”. The comparison of expression levels of these four transcription factors revealed that the least and the greatest expressions were recorded for CBF1 and CBF3 respectively, and two CBF2 and CBF4 had approximately the same expression levels. PMID:26973374

  9. Ocular Blood Flow and Normal Tension Glaucoma

    Directory of Open Access Journals (Sweden)

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  10. Dexmedetomidine decreases the oral mucosal blood flow.

    Science.gov (United States)

    Kawaai, Hiroyoshi; Yoshida, Kenji; Tanaka, Eri; Togami, Kohei; Tada, Hitoshi; Ganzberg, Steven; Yamazaki, Shinya

    2013-12-01

    There is an abundance of blood vessels in the oral cavity, and intraoperative bleeding can disrupt operations. There have been some interesting reports about constriction of vessels in the oral cavity, one of which reported that gingival blood flow in cats is controlled by sympathetic α-adrenergic fibres that are involved with vasoconstriction. Dexmedetomidine is a sedative and analgesic agent that acts through the α-2 adrenoceptor, and is expected to have a vasoconstrictive action in the oral cavity. We have focused on the relation between the effects of α-adrenoceptors by dexmedetomidine and vasoconstriction in oral tissues, and assessed the oral mucosal blood flow during sedation with dexmedetomidine. The subjects comprised 13 healthy male volunteers, sedated with dexmedetomidine in a loading dose of 6 μg/kg/h for 10 min and a continuous infusion of 0.7 μg/kg/h for 32 min. The mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), systemic vascular resistance (SVR), and palatal mucosal blood flow (PMBF) were measured at 0, 5, 10, 12, 22, and 32 min after the start of the infusion. The HR, CO, and PBMF decreased significantly during the infusion even though there were no differences in the SV. The SVR increased significantly but the PMBF decreased significantly. In conclusion, PMBF was reduced by the mediating effect of dexmedetomidine on α-2 adrenoceptors.

  11. Hypersensitivity to thromboxane receptor mediated cerebral vasomotion and CBF oscillations during acute NO-deficiency in rats.

    Directory of Open Access Journals (Sweden)

    Béla Horváth

    Full Text Available BACKGROUND: Low frequency (4-12 cpm spontaneous fluctuations of the cerebrovascular tone (vasomotion and oscillations of the cerebral blood flow (CBF have been reported in diseases associated with endothelial dysfunction. Since endothelium-derived nitric oxide (NO suppresses constitutively the release and vascular effects of thromboxane A(2 (TXA(2, NO-deficiency is often associated with activation of thromboxane receptors (TP. In the present study we hypothesized that in the absence of NO, overactivation of the TP-receptor mediated cerebrovascular signaling pathway contributes to the development of vasomotion and CBF oscillations. METHODOLOGY/PRINCIPAL FINDINGS: Effects of pharmacological modulation of TP-receptor activation and its downstream signaling pathway have been investigated on CBF oscillations (measured by laser-Doppler flowmetry in anesthetized rats and vasomotion (measured by isometric tension recording in isolated rat middle cerebral arteries, MCAs both under physiological conditions and after acute inhibition of NO synthesis. Administration of the TP-receptor agonist U-46619 (1 µg/kg i.v. to control animals failed to induce any changes of the systemic or cerebral circulatory parameters. Inhibition of the NO synthesis by nitro-L-arginine methyl ester (L-NAME, 100 mg/kg i.v. resulted in increased mean arterial blood pressure and a decreased CBF accompanied by appearance of CBF-oscillations with a dominant frequency of 148±2 mHz. U-46619 significantly augmented the CBF-oscillations induced by L-NAME while inhibition of endogenous TXA(2 synthesis by ozagrel (10 mg/kg i.v. attenuated it. In isolated MCAs U-46619 in a concentration of 100 nM, which induced weak and stable contraction under physiological conditions, evoked sustained vasomotion in the absence of NO, which effect could be completely reversed by inhibition of Rho-kinase by 10 µM Y-27632. CONCLUSION/SIGNIFICANCE: These results suggest that hypersensitivity of the TP

  12. The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

    Science.gov (United States)

    Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

    2015-01-01

    Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference.

  13. Regional cerebral blood flow in children with autism spectrum disorders: a quantitative 99mTc-ECD brain SPECT study with statistical parametric mapping evaluation

    Institute of Scientific and Technical Information of China (English)

    YANG Wen-han; JING Jin; XIU Li-juan; CHENG Mu-hua; WANG Xin; BAO Peng; WANG Qing-xiong

    2011-01-01

    Background Autism spectrum disorders (ASD), which include autism, asperger syndrome (AS) and pervasive developmental disorder-not otherwise specified (PDD-NOS), are devastating neurodevelopmental disorders of childhood resulting in deficits in social interaction, repetitive patterns of behaviors, and restricted interests and activities. Single photon emission computed tomography (SPECT) is a common technique used to measure regional cerebral blood flow (rCBF). Several studies have measured rCBF in children with ASD using SPECT, however, findings are discordant. In addition, the majority of subjects used in these studies were autistic. In this study, we aimed to investigate changes in rCBF in children with ASD using SPECT.Methods A Technetium-99m-ethyl cysteinate dimmer (99mTc-ECD) brain SPECT study was performed on an ASD group consisting of 23 children (3 girls and 20 boys; mean age (7.2±3.0) years) who were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-Ⅳ) criteria and an age-matched control group with 8children (1 girl and 7 boys, mean age (5.5±2.4) years). Image data were evaluated with Statistical Parametric Mapping,5th version (SPM5). A Student's t test for unpaired data was used to compare rCBF and asymmetry in the autism and corresponding control group. The covariance analysis, taking age as covariance, was performed between the ASD and control group.Results There was a significant reduction in rCBF in the bilateral frontal lobe (frontal poles, arcula frontal gyrus) and the bilateral basal ganglia in the autism group, and a reduction in the bilateral frontal, temporal, parietal, legumina nucleus and cerebellum in the AS group compared to the control. In addition, asymmetry of hemispheric hypoperfusion in the ASD group was observed. Inner-group comparison analysis revealed that rCBF decreased significantly in the bilateral frontal lobe (42.7%), basal nucleus (24.9%) and temporal lobe (22.8%) in the autism

  14. Cerebral blood flow autoregulation in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten

    2001-01-01

    Ph.d. afhandlingen omhandler sammenhængen mellem hjernens blodtilførsel (CBF) og middelarterietrykket (MAP) hos patienter med akut bakteriel meningitis. Hos raske er CBF uafhængig af MAP, hvilket kaldes CBF autoregulation. Svækket autoregulation antages at øge risikoen for cerebral hypoperfusion ...

  15. Correlation of acute-phase cerebral blood flow and MRI findings with outcome in patients with diffuse axonal injury

    Energy Technology Data Exchange (ETDEWEB)

    Akimoto, Hideaki; Takasato, Yoshio; Masaoka, Hiroyuki; Hayakawa, Takanori; Yatsushige, Hiroshi; Toumori, Toshiki; Sugawara, Takashi [National Disaster Medical Center, Tachikawa, Tokyo (Japan)

    2003-01-01

    The purpose of this study was to assess the utility of acute-phase cerebral blood flow (CBF) measurements and magnetic resonance imaging (MRI) for predicting the outcome of patients with diffuse axonal injury (DAI). Twenty-one DAI patients treated at our hospital between July 1997 and December 1999 were evaluated. CBF was measured using Xenon computed tomography. Axial T1-, axial T2-, and sagittal T2-weighted MRI scans were performed using a 0.5 Tesla MR scanner. Each examination was performed within seven days of the onset of symptoms. Patients were divided into two groups according to their Glasgow outcome scale after six months: a good outcome group (n=14, good recovery or moderate disability), and a poor outcome group (n=7, severe disability, vegetative state or death). We compared the inter-group average ages, Glasgow coma scale (GCS) ratings upon admission, and CBF values using the Student t-test. Inter-group differences regarding the presence of lesions on MRI images were assessed using the Mann-Whitney test. The age of the good outcome group was significantly lower than that of the poor outcome group (31.4{+-}15.1 years vs 49.6{+-}24.1 years; p<0.05). The GCS ratings were not significantly different (7.1{+-}2.2 vs 5.9{+-}1.5). The CBF of the good outcome group tended to be higher than that of the poor outcome group, but the difference was not statistically significant (43.2{+-}12.8 ml/100 g/min vs 33.6{+-}7.4 ml/100 g/min). The presence of lesions in the thalamus and brain stem on MRI images was correlated with the outcome of the patients, especially in patients with a lesion in their brain stem (p<0.01). Lesions in the corpus callosum were observed in both groups, and their presence was not correlated with patient outcome. We conclude that DAI patients who are older or whose MRI examinations reveal the presence of a lesion in their brain stem may have difficulty leading an independent daily life and that the prognosis of acute-phase DAI patients cannot be

  16. Red blood cell clusters in Poiseuille flow

    Science.gov (United States)

    Ghigliotti, Giovanni; Selmi, Hassib; Misbah, Chaouqi; Elasmi, Lassaad

    2011-11-01

    We present 2D numerical simulations of sets of vesicles (closed bags of a lipid bilayer membrane) in a parabolic flow, a setup that mimics red blood cells (RBCs) in the microvasculature. Vesicles, submitted to sole hydrodynamical interactions, are found to form aggregates (clusters) of finite size. The existence of a maximal cluster size is pointed out and characterized as a function of the flow intensity and the swelling ratio of the vesicles. Moreover bigger clusters move at lower velocity, a fact that may prove of physiological interest. These results quantify previous observations of the inhomogeneous distribution of RBCs in vivo (Gaehtgens et al., Blood Cells 6 - 1980). An interpretation of the phenomenon is put forward based on the presence of boli (vortices) between vesicles. Both the results and the explanation can be transposed to the three-dimensional case.

  17. Deterministic Aperiodic Sickle Cell Blood Flows

    Science.gov (United States)

    Atsaves, Louis; Harris, Wesley

    2013-11-01

    In this paper sickle cell blood flow in the capillaries is modeled as a hydrodynamical system. The hydrodynamical system consists of the axisymmetric unsteady, incompressible Navier-Stokes equations and a set of constitutive equations for oxygen transport. Blood cell deformation is not considered in this paper. The hydrodynamical system is reduced to a system of non-linear partial differential equations that are then transformed into a system of three autonomous non-linear ordinary differential equations and a set of algebraic equations. We examine the hydrodynamical system to discern stable/unstable, periodic/nonperiodic, reversible/irreversible properties of the system. The properties of the solutions are driven in large part by the coefficients of the governing system of equations. These coefficients depend on the physiological properties of the sickle cell blood. The chaotic nature of the onset of crisis in sickle cell patients is identified. Research Assistant.

  18. Computational Analysis of Human Blood Flow

    Science.gov (United States)

    Panta, Yogendra; Marie, Hazel; Harvey, Mark

    2009-11-01

    Fluid flow modeling with commercially available computational fluid dynamics (CFD) software is widely used to visualize and predict physical phenomena related to various biological systems. In this presentation, a typical human aorta model was analyzed assuming the blood flow as laminar with complaint cardiac muscle wall boundaries. FLUENT, a commercially available finite volume software, coupled with Solidworks, a modeling software, was employed for the preprocessing, simulation and postprocessing of all the models.The analysis mainly consists of a fluid-dynamics analysis including a calculation of the velocity field and pressure distribution in the blood and a mechanical analysis of the deformation of the tissue and artery in terms of wall shear stress. A number of other models e.g. T branches, angle shaped were previously analyzed and compared their results for consistency for similar boundary conditions. The velocities, pressures and wall shear stress distributions achieved in all models were as expected given the similar boundary conditions. The three dimensional time dependent analysis of blood flow accounting the effect of body forces with a complaint boundary was also performed.

  19. Comparison of global cerebral blood flow measured by phase‐contrast mapping MRI with 15O‐H2O positron emission tomography

    Science.gov (United States)

    Lindberg, Ulrich; Aachmann‐Andersen, Niels Jacob; Lisbjerg, Kristian; Christensen, Søren Just; Rasmussen, Peter; Olsen, Niels Vidiendal; Law, Ian; Larsson, Henrik Bo Wiberg; Henriksen, Otto Mølby

    2016-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase‐contrast mapping magnetic resonance imaging (PCM MRI) and by 15O‐H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo against an accepted reference technique. Materials and Methods Same‐day measurements of CBF by 15O‐H2O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one‐tissue compartment model with measurement of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume‐segmented 3D T 1‐weighted anatomical MR‐scan. Results Mean CBF was 34.9 ± 3.4 mL/100 g/min measured by 15O‐H2O PET and 57.0 ± 6.8 mL/100 g/min measured by PCM MRI. The measurements were highly correlated (P = 0.0008, R2 = 0.44), although values obtained by PCM MRI were higher compared to 15O‐H2O PET (absolute and relative differences were 22.0 ± 5.2 mL/100 g/min and 63.4 ± 14.8%, respectively). Conclusion This study confirms the use of PCM MRI for quantification of global CBF, but also that PCM MRI systematically yields higher values relative to 15O‐H2O PET, probably related to methodological bias. Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:692–699. PMID:27619317

  20. Intrathoracic Pressure Regulation Improves Cerebral Perfusion and Cerebral Blood Flow in a Porcine Model of Brain Injury.

    Science.gov (United States)

    Metzger, Anja; Rees, Jennifer; Kwon, Young; Matsuura, Timothy; McKnite, Scott; Lurie, Keith G

    2015-08-01

    Brain injury is a leading cause of death and disability in children and adults in their most productive years. Use of intrathoracic pressure regulation (IPR) to generate negative intrathoracic pressure during the expiratory phase of positive pressure ventilation improves mean arterial pressure and 24-h survival in porcine models of hemorrhagic shock and cardiac arrest and has been demonstrated to decrease intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in these models. Application of IPR for 240 min in a porcine model of intracranial hypertension (ICH) will increase CPP when compared with controls. Twenty-three female pigs were subjected to focal brain injury by insertion of an epidural Foley catheter inflated with 3 mL of saline. Animals were randomized to treatment for 240 min with IPR set to a negative expiratory phase pressure of -12 cmH2O or no IPR therapy. Intracranial pressure, mean arterial pressure, CPP, and cerebral blood flow (CBF) were evaluated. Intrathoracic pressure regulation significantly improved mean CPP and CBF. Specifically, mean CPP after 90, 120, 180, and 240 min of IPR use was 43.7 ± 2.8 mmHg, 44.0 ± 2.7 mmHg, 44.5 ± 2.8 mmHg, and 43.1 ± 1.9 mmHg, respectively; a significant increase from ICH study baseline (39.5 ± 1.7 mmHg) compared with control animals in which mean CPP was 36.7 ± 1.4 mmHg (ICH study baseline) and then 35.9 ± 2.1 mmHg, 33.7 ± 2.8 mmHg, 33.9 ± 3.0 mmHg, and 36.0 ± 2.7 mmHg at 90, 120, 180, and 240 min, respectively (P blood flow, as measured by an invasive CBF probe, increased in the IPR group (34 ± 4 mL/100 g-min to 49 ± 7 mL/100 g-min at 90 min) but not in controls (27 ± 1 mL/100 g-min to 25 ± 5 mL/100 g-min at 90 min) (P = 0.01). Arterial pH remained unchanged during the entire period of IPR compared with baseline values and control values. In this anesthetized pig model of ICH, treatment with IPR significantly improved CPP and CBF. This therapy may be of clinical value by noninvasively

  1. Blood flow measurements and clot detection with nearinfrared spectroscopy

    OpenAIRE

    Rossow, MJ; Gatto, R.; D'amico, E.; Mantulin, WW; Gratton, E

    2006-01-01

    Detecting impeded blood flow and locating the clot causing it is a major challenge in neurosurgery. We propose an instrument that uses near-infrared spectroscopy to simultaneously detect clots and measure blood flow. © 2006 Optical Society of America.

  2. Modeling of cerebral oxygen transport based on in vivo microscopic imaging of microvascular network structure, blood flow and oxygenation

    Directory of Open Access Journals (Sweden)

    Louis Gagnon

    2016-08-01

    Full Text Available 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.

  3. Effects of resveratrol alone or in combination with piperine on cerebral blood flow parameters and cognitive performance in human subjects: a randomised, double-blind, placebo-controlled, cross-over investigation

    OpenAIRE

    Wightman, Emma; Reay, Jonathon; Haskell, Crystal; Williamson, Gary; Dew, Tristan; Kennedy, David

    2014-01-01

    Previous research has shown that resveratrol can increase cerebral blood flow (CBF) in the absence of improved cognitive performance in healthy, young human subjects during the performance of cognitively demanding tasks. This lack of cognitive effects may be due to low bioavailability and, in turn, reduced bioefficacy of resveratrol in vivo. Piperine can alter polyphenol pharmacokinetics, but previous studies have not investigated whether this affects the efficacy of the target compound. Ther...

  4. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

  5. Average blood flow and oxygen uptake in the human brain during resting wakefulness

    DEFF Research Database (Denmark)

    Madsen, P L; Holm, S; Herning, M;

    1993-01-01

    tracer between the brain and its venous blood is not reached. As a consequence, normal values for CBF and CMRO2 of 54 ml 100 g-1 min-1 and 3.5 ml 100 g-1 min-1 obtained with the Kety-Schmidt technique are an overestimation of the true values. Using the Kety-Schmidt technique we have performed 57...

  6. Studies of cerebral blood flow and metabolism in patients with senile dementia of the Alzheimer's type and diagnostic evaluation of the dementing illnesses by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Shizuki (Nippon Medical School, Tokyo (Japan))

    1990-06-01

    This study was designed to determine cerebral dysfunction in senile dementia of the Alzheimer's type (SDAT). Regional cerebral blood flow (rCBF), oxygen extraction fraction and cerebral oxygen consumption (rCMRO{sub 2}) were studied in SDAT patients (n=16) and age-matched normal elderly people (n=5) by positron emission tomography (PET) using the O-15 labeled CO{sub 2} and O{sub 2} inhalation technique. The SDAT group had a significantly lower values in both rCBF and rCMRO{sub 2} than the normal control. During the early stage of SDAT, rCMRO{sub 2} was restricted to the temporal cortex; and it extended to the parietal and frontal cortices associated with a decreased rCBF as the disease progressed. Posterior temporal and posterior parietal association cortices were considered to be the most damageable part during the early stage. Bilateral differences in oxygen metabolism of the temporal and parietal cortices tended to be in accordance with clinical symptoms for disturbed speech and visuospatial function, suggesting the correlation between rCMRO{sub 2} and rCBF in SDAT. Findings of PET in SDAT differed from those obtained in each patient with multi-infarct dementia or Pick disease, in that both rCBF and rCMRO{sub 2} were inhomogeneously decreased over the whole cerebral cortex for multi-infarct dementia and in that homogeneously decreased rCBF and rCMRO{sub 2} were restricted to the frontal and temporal cortices for Pick disease. PET may have a potential for differentiating various types of dementia. (N.K.).

  7. Blood flow in healed and inflamed periodontal tissues of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non-inflamed healed gingiva (32.1 +- 2.7 ml/min/100 g) than in inflamed gingiva (46.1 +- 5.3 ml/min/100 g). No differences in the blood flow of the alveolar bone underlying inflamed or non-inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non-ligated teeth (p<0.03). The difference in blood flow between gingiva with G.I.>1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow.

  8. Effects of isoflurane, fentanyl, or thiopental anesthesia on regional cerebral blood flow and brain surface PO2 in the presence of a focal lesion in rabbits.

    Science.gov (United States)

    Murr, R; Schürer, L; Berger, S; Enzenbach, R; Peter, K; Baethmann, A

    1993-11-01

    These studies were conducted to determine the effect of anesthetic drugs on tissue perfusion and O2 supply in the brain with focal cerebral edema. Using an open cranium preparation, we studied the effects of isoflurane (I; 1 minimum alveolar anesthetic concentration), of fentanyl (F; 0.5-1 microgram.kg-1 x min-1), or of thiopental (T; 32.5 mg.kg-1 x h-1) on regional cerebral blood flow (rCBF) and regional brain tissue PO2 in albino rabbits (n = 6 per group) with a focal brain lesion (cold injury). The doses of anesthetics were sufficient to suppress nociception. rCBF (H2 clearance) and tissue PO2 (multiwire surface electrode) were studied adjacent to and distant from the lesion. Cerebral hyperemia developed immediately after trauma in all groups, although the flow increase did not attain statistical significance. rCBF was subsequently reduced by about 25% in the vicinity of the lesion. Distant from the trauma, a continuing hyperemia (+30%) was later observed in animals with isoflurane, whereas rCBF was decreased then by 10%-20% in animals with fentanyl, or was unchanged with thiopental. Brain tissue PO2 was increased with isoflurane in areas distant from the lesion, but decreased with fentanyl. However, with thiopental, the PO2 level had already been lowered before trauma with a subsequent tendency toward normalization. The heterogeneity of the tissue PO2 in fentanyl anesthesia, as well as the increased frequency of hypoxic PO2 values with thiopental, might have resulted from microcirculatory disturbances. Thus, although isoflurane seemed to facilitate hyperemia with an increased O2 supply to the brain, fentanyl tended to induce the opposite response. Although these properties suggest the potential to manipulate perfusion and O2 supply in cerebral ischemia or hyperemia after head injury, the effects of such measures on intracranial pressure, neurologic status, and outcome have yet to be proven.

  9. Skin blood flow changes during apneic spells in preterm infants

    NARCIS (Netherlands)

    Suichies, H.E.; Aarnoudse, J.G.; Okken, A.; Jentink, H.W.; Mul, de F.F.M.; Greve, J.

    1989-01-01

    Changes in skin blood flow during apneic spells were determined in 18 preterm infants using a diode laser Doppler flow meter without light conducting fibres. Heart rate, nasal air flow, impedance pneumography, skin and incubator temperature and laser Doppler skin blood flow were recorded simultaneou

  10. Nonlinear interactions in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, Donald J.; Sosnovtseva, Olga; Chon, Ki H.

    2005-01-01

    , identical except for the strength of TGF input, with a third, fixed resistance segment representing prearteriolar vessels. The two arteriolar segments are electrically coupled. The arteriolar, glomerular, and tubular models are linked; TGF modulates arteriolar circumference, which determines vascular...... resistance and glomerular capillary pressure. The model couples TGF input to voltage-gated Ca channels. It predicts autoregulation of GFR and renal blood flow, matches experimental measures of tubular pressure and macula densa NaCl concentration, and predicts TGF-induced oscillations and a faster smaller...

  11. Absolute quantification of myocardial blood flow.

    Science.gov (United States)

    Yoshinaga, Keiichiro; Manabe, Osamu; Tamaki, Nagara

    2016-07-21

    With the increasing availability of positron emission tomography (PET) myocardial perfusion imaging, the absolute quantification of myocardial blood flow (MBF) has become popular in clinical settings. Quantitative MBF provides an important additional diagnostic or prognostic information over conventional visual assessment. The success of MBF quantification using PET/computed tomography (CT) has increased the demand for this quantitative diagnostic approach to be more accessible. In this regard, MBF quantification approaches have been developed using several other diagnostic imaging modalities including single-photon emission computed tomography, CT, and cardiac magnetic resonance. This review will address the clinical aspects of PET MBF quantification and the new approaches to MBF quantification.

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

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil;

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate...... 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 that damages neurons after stroke....

  13. Decorrelation-based blood flow velocity estimation: effect of spread of flow velocity, linear flow velocity gradients, and parabolic flow.

    NARCIS (Netherlands)

    Lupotti, F.A.; Steen, A.F.W. van der; Mastik, F.; Korte, C.L. de

    2002-01-01

    In recent years, a new method to measure transverse blood flow, based on the decorrelation of the radio frequency (RF) signals has been developed. In this paper, we investigated the influence of nonuniform flow on the velocity estimation. The decorrelation characteristics of transverse blood flow us

  14. Changes in regional cerebral blood flow in nondominant hemisphere during speech task in aphasics. A PET activation study

    Energy Technology Data Exchange (ETDEWEB)

    Ohyama, Masashi; Kitamura, Shin; Mishina, Masahiro; Terashi, Akiro [Nippon Medical School, Tokyo (Japan); Senda, Michio; Ishii, Kenji

    1995-08-01

    To investigate the patients with language disorder and to detect the activated areas in language processing, we measured the changes in the regional cerebral blood flow (CBF) during speech task (`counting` task) using O-15 water PET activation technique in six normal subjects (age 58.3 {+-}8.1, mean{+-}SD), ten fluent aphasics (age 60.3{+-}12.5) and six nonfluent aphasics (age 50.5{+-}8.3). In `counting` task, the subjects were instructed to count the number aloud from 1 to 10 and repeat the sequence over and over in the native language (Japanese) at the rate of one number per 2.5 sec. The data were analyzed with stereotactic intersubject averaging analysis for the normal subjects. Apart from it, the regions of interest (ROI) analysis (a circular ROI of 12 mm diameter) was performed in the language-related area for each subject. In the normal subjects, the language-related areas: posteroinferofrontal areas (PIF), posterosuperotemporal area (PST), and Rolandic areas (related to the mouth and lips) were significantly activated bilaterally in the `counting` task. PIF were activated with a dominance in the left side. In the resting state, rCBF in the left PIF and left PST was reduced in both fluent and nonfluent aphasics. In nonfluent aphasics, the magnitude of activation in the right PIF by `counting` task was significantly greater than normal subjects and patients with fluent aphasia (ANOVA). It suggests the importance of the right PIF in the simple language processing in the nonfluent aphasia. In the sixteen aphasic patients, the increase in rCBF in the right PST during the `counting` task was negatively correlated with the score of comprehension (WAB) in the Spearman ranked correlation (p<0.05). It suggests that, while the activity of the right PST is minimal for the `counting` in normal subjects, it plays an important and compensatory role in aphasic patients. (author).

  15. Tissue blood flow mapping using laser technology

    Science.gov (United States)

    Wardell, Karin; Linden, Maria; Nilsson, Gert E.

    1995-03-01

    By the introduction of the laser Doppler perfusion imager (LDPI) the microvascular blood flow in a tissue area can be mapped by sequentially moving a laser beam over the tissue. The measurement is performed without touching the tissue and the captured perfusion values in the peripheral circulation are presented as a color-coded image. In the ordinary LDPI-set-up, 64 X 64 measurement sites cover an area in the range of about 10 - 150 cm2 depending on system settings. With a high resolution modification, recordings can be done on tissue areas as small as 1 cm2. This high resolution option has been assessed in animal models for the mapping of small vessels. To be able to record not only spatial but also temporal perfusion components of tissue blood flow, different local area scans (LAS) have been developed. These include single point recording as well as integration of either 2 X 2, 3 X 3, or 4 X 4 measurement sites. The laser beam is repeatedly moved in a quadratic pattern over the small tissue area of interest and the output value constitutes the average perfusion of all captured values within the actual region. For the evaluation, recordings were performed on healthy volunteers before and after application of a vasodilatating cream on the dorsal side of the hand.

  16. ERK1/2 inhibition attenuates cerebral blood flow reduction and abolishes ET(B) and 5-HT(1B) receptor upregulation after subarachnoid hemorrhage in rat

    DEFF Research Database (Denmark)

    Beg, Saema A S; Hansen-Schwartz, Jacob A; Vikman, Petter J

    2006-01-01

    -regulated kinase (ERK1/2). In the present study, we hypothesized that inhibition of ERK1/2 alters the ET(B) and 5-HT(1B) receptor upregulation and at the same time prevents the sustained cerebral blood flow (CBF) reduction associated with SAH. The ERK1/2 inhibitor SB386023-b was injected intracisternally...... in conjunction with and after the induced SAH in rats. At 2 days after the SAH, cerebral arteries were harvested for quantitative real-time polymerase chain reaction, immunohistochemistry and analysis of contractile responses to endothelin-1 (ET-1; ET(A) and ET(B) receptor agonist) and 5-carboxamidotryptamine (5...

  17. A comparative cerebral blood flow study in a baboon model with acetazolamide provocation: {sup 99m}Tc-HMPAO vs {sup 123}I(IMP)

    Energy Technology Data Exchange (ETDEWEB)

    Dormehl, I.C.; Oliver, D.W.; Hugo, N.; Rossouw, D

    1995-04-01

    Pharmacological interactions are important when nuclear medical procedures are applied to patients under drug therapy, or drug provocation. This study compares in baboon models (regional) cerebral blood flow [(r)CBF] results from {sup 99m}Tc-HMPAO and {sup 123}I-iodoamphetamine [{sup 123}I(IMP)] each with and without acetazolamide, the latter a suggested drug for testing cerebrovascular reserve. Expected differences in cerebral uptake were observed between the two radio-tracers without acetazolamide. The increase in tracer uptake resulting from acetazolamide is significantly enhanced for {sup 123}I(IMP), which could have diagnostic implications.

  18. Protein kinase C inhibition prevents upregulation of vascular ET(B) and 5-HT(1B) receptors and reverses cerebral blood flow reduction after subarachnoid haemorrhage in rats

    DEFF Research Database (Denmark)

    Beg, Saema S; Hansen-Schwartz, Jacob A; Vikman, Petter J;

    2007-01-01

    type 1B (5-HT(1B)) receptor upregulation and prevent the associated cerebral blood flow (CBF) reduction. The PKC inhibitor RO-31-7549 or vehicle was injected intracisternally after the induced SAH in rats (n=3 to 10 in each groups for each method). The involvement of the PKC isoforms was investigated...... by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. Administration of RO-31-7549 prevented the upregulated contraction elicited by application of ET-1 and 5-CT in cerebral arteries and kept the ET(B) and 5-HT(1B) receptor mRNA and protein levels at pre-SAH levels. Regional...

  19. Effects of low-frequency repetitive transcranial magnetic stimulation combined with intensive speech therapy on cerebral blood flow in post-stroke aphasia.

    Science.gov (United States)

    Hara, Takatoshi; Abo, Masahiro; Kobayashi, Kentaro; Watanabe, Motoi; Kakuda, Wataru; Senoo, Atushi

    2015-10-01

    We provided an intervention to chronic post-stroke aphasic patients using low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) guided by a functional magnetic resonance imaging (fMRI) evaluation of language laterality, combined with intensive speech therapy (ST). We performed a single photon emission-computed tomography (SPECT) scan pre- and post-intervention and investigated the relationship between cerebral blood flow (CBF) and language function. Fifty right-handed chronic post-stroke aphasic patients were enrolled in the study. During their 11-day hospital admission, the patients received a 40-min session of 1-Hz LF-rTMS on the left or right hemisphere, according to language localization identified by the fMRI evaluation, and intensive ST daily for 10 days, except for Sunday. A SPECT scan and language evaluation by the Standard Language Test of Aphasia (SLTA) were performed at the time of admission and at 3 months following discharge. We calculated laterality indices (LIs) of regional CBF (rCBF) in 13 language-related Brodmann area (BA) regions of interest. In patients who received LF-rTMS to the intact right hemisphere (RH-LF-rTMS), the improvement in the total SLTA score was significantly correlated with the pre- and post-intervention change of LI (ΔLI) in BA44. In patients who received LF-rTMS to the lesional left hemisphere (LH-LF-rTMS), this association was not observed. Analyses of the SLTA subscales and rCBF ΔLI demonstrated that in the RH-LF-rTMS group, the SLTA Speaking subscale scores were significantly correlated with ΔLIs in BA11, 20, and 21, and the SLTA Writing subscale scores were significantly correlated with ΔLIs in BA6 and 39. Conversely, in the LH-LF-rTMS group, the SLTA Speaking subscale scores were correlated with ΔLI in BA10, and the SLTA Reading subscale scores were significantly correlated with ΔLIs in BA13, 20, 22, and 44. Our results suggest the possibility that fMRI-guided LF-rTMS combined with intensive ST may

  20. Estimation of cerebral blood flow during cardiopulmonary resuscitation in humans

    DEFF Research Database (Denmark)

    Christensen, S F; Stadeager, Carsten Preben; Siemkowicz, E

    1990-01-01

    /kg/min). The cortical CBF was found between 14 and 211 ml 100 g-1.min-1 with mean 42 ml 100 g-1.min-1 and mean white matter CBF equal to 27 ml 100 g-1.min-1. It is suggested that the external cardiac massage in humans may be of poor efficacy in terms of brain revival. Cortical CBF after long-lasting cardiopulmonary...

  1. Alterations of Regional Cerebral Blood Flow in Tinnitus Patients as Assessed Using Single-Photon Emission Computed Tomography.

    Directory of Open Access Journals (Sweden)

    Takashi Ueyama

    Full Text Available Tinnitus is the perception of phantom sound without an external auditory stimulus. Using neuroimaging techniques, such as positron emission tomography, electroencephalography, magnetoencephalography, and functional magnetic resonance imaging (fMRI, many studies have demonstrated that abnormal functions of the central nervous system are closely associated with tinnitus. In our previous research, we reported using resting-state fMRI that several brain regions, including the rectus gyrus, cingulate gyrus, thalamus, hippocampus, caudate, inferior temporal gyrus, cerebellar hemisphere, and medial superior frontal gyrus, were associated with tinnitus distress and loudness. To reconfirm these results and probe target regions for repetitive transcranial magnetic stimulation (rTMS, we investigated the regional cerebral blood flow (rCBF between younger tinnitus patients (<60 years old and the age-matched controls using single-photon emission computed tomography and easy Z-score imaging system. Compared with that of controls, the rCBF of tinnitus patients was significantly lower in the bilateral medial superior frontal gyri, left middle occipital gyrus and significantly higher in the bilateral cerebellar hemispheres and vermis, bilateral middle temporal gyri, right fusiform gyrus. No clear differences were observed between tinnitus patients with normal and impaired hearing. Regardless of the assessment modality, similar brain regions were identified as characteristic in tinnitus patients. These regions are potentially involved in the pathophysiology of chronic subjective tinnitus.

  2. Cerebral blood flow is diminished in asymptomatic middle-aged adults with maternal history of Alzheimer's disease.

    Science.gov (United States)

    Okonkwo, Ozioma C; Xu, Guofan; Oh, Jennifer M; Dowling, N Maritza; Carlsson, Cynthia M; Gallagher, Catherine L; Birdsill, Alex C; Palotti, Matthew; Wharton, Whitney; Hermann, Bruce P; LaRue, Asenath; Bendlin, Barbara B; Rowley, Howard A; Asthana, Sanjay; Sager, Mark A; Johnson, Sterling C

    2014-04-01

    Cerebral blood flow (CBF) provides an indication of the metabolic status of the cortex and may have utility in elucidating preclinical brain changes in persons at risk for Alzheimer's disease (AD) and related diseases. In this study, we investigated CBF in 327 well-characterized adults including patients with AD (n = 28), patients with amnestic mild cognitive impairment (aMCI, n = 23), older cognitively normal (OCN, n = 24) adults, and asymptomatic middle-aged adults (n = 252) with and without a family history (FH) of AD. Compared with the asymptomatic cohort, AD patients displayed significant hypoperfusion in the precuneus, posterior cingulate, lateral parietal cortex, and the hippocampal region. Patients with aMCI exhibited a similar but less marked pattern of hypoperfusion. Perfusion deficits within the OCN adults were primarily localized to the inferior parietal lobules. Asymptomatic participants with a maternal FH of AD showed hypoperfusion in hippocampal and parietofrontal regions compared with those without a FH of AD or those with only a paternal FH of AD. These observations persisted when gray matter volume was included as a voxel-wise covariate. Our findings suggest that having a mother with AD might confer a particular risk for AD-related cerebral hypoperfusion in midlife. In addition, they provide further support for the potential utility of arterial spin labeling for the measurement of AD-related neurometabolic dysfunction, particularly in situations where [18F]fluorodeoxyglucose imaging is infeasible or clinically contraindicated.

  3. Low cerebral blood flow in hypotensive perinatal distress

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Friis-Hansen, B

    1977-01-01

    was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays...

  4. Analysis of regional cerebral blood flow and distribution volume in Machado-Joseph disease by iodine-{sup 123}I IMP single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Tsunemi; Nakajima, Takashi; Fukuhara, Nobuyoshi [National Saigata Hospital, Ohagata, Niigata (Japan)

    2001-09-01

    Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Its clinical features vary greatly in different generations of the same family. Regional cerebral blood flow (rCBF) and distribution volume (V{sub d}) in the pons, cerebellum, and cerebral cortex were measured in 12 patients with MJD by autoradiography (ARG) and the table look-up (TLU) method of iodine-123 IMP ({sup 123}I-IMP) single photon emission computed tomography (SPECT). Representative cases were as follows: A 46-year-old woman first experienced gait ataxia at age 38. Computed tomography (CT) and magnetic resonance imaging (MRI) showed no atrophy in the pons or cerebellum, but rCBF measured by the {sup 123}I-IMP SPECT ARG method detected hypoperfusion in the pons, and cerebellar vermis and hemisphere. A 76-year-old woman first experienced gait ataxia at age 69. CT and MRI findings showed severe atrophy in the pons, and cerebellar vermis and hemisphere. Moreover, rCBF was decreased in the pons, whereas it was not decreased in the cerebellar vermis and hemisphere. In the pons of patients with MJD, rCBF was markedly decreased regardless of disease severity. Because this SPECT finding for the pons looked like a 'dot', we have called it the 'pontine dot sign'. In the MJD group, rCBF was significantly decreased in the pons (Student's t test, p<0.01) and cerebellar vermis (p<0.05). The V{sub d} was also significantly decreased in the pons (p<0.005) in comparison with that for normal subjects. Pearson's correlation analysis yielded a significant relationship between the rCBF in the pons and age at onset (r=0.578, p<0.05). There was a strong correlation between the V{sub d} for the pons and age at onset (r=0.59, p<0.05). Person's correlation analysis also showed a significant relationship between the V{sub d} in the cerebellar hemispheres and International Cooperative Ataxia Rating Scale (r=0.644, p<0.05). The pontine rCBFs in patients with early onset MJD

  5. Characteristics of cerebral regional blood flow in patients with palmar hyperhidrosis%手汗症患者手术前后脑血流灌注显像研究

    Institute of Scientific and Technical Information of China (English)

    涂远荣; 李旭; 林敏; 赖繁彩; 陈剑锋; 邱明链

    2009-01-01

    Objective To observe the characteristics of cerebral regional blood flow (rCBF) in the patients with palmar hyperhidrosis,and to explore the passible mechanism for the development of pal-mar hyperhidrosis. Methods SPECT 99Tcm-ECD was used to quantitatively determine rCBF of patients with palmar hyperhidrosis who underwent endoscopic thoracic sympathectomy. The preoperative rCBF mode was analyzed, and the preoperative and postoperative mode of rCBF was compared. Results The one later-al high rCBF zone was observed at basal nucleus area in 9 cases out of 10 cases. The blood flow of high rCBF zones was significantly decreased after sympathectomy (Ra value 1.7.0±0.19 vs 1.10±0.06, P< 0.05). The blood flow change rate was (42.00±6.92) %. Conclusion The basal nucleus may play an important role in the development of palmar hyperhidrosis and compensatoy sweating.%目的 观察手汗症患者手术治疗前后脑血流灌注特点,探讨手汗症中枢神经系统的可能发病机制.方法 采用单光子发射断层扫描(SPECT)方法,对10例手汗症患者行胸交感神经切断术前后的脑血流灌注进行半定量分析,观察术前脑血流灌注特点并比较手术前后的血流灌注变化.结果 10例术前患者中有9例表现为一侧基底节脑血流灌注增高,其中轻度增高1例,明显增高8例.放射性增高灶术前Ra值为(1.70±0.19),手术后下降为(1.10±0.06),平均下降值为(42.00±6.92)%(P<0.05).结论 基底节神经功能活动与手汗症的发病及术后代偿性多汗的出现有一定关系.

  6. Voxel-based comparison of rCBF SPET images in frontotemporal dementia and Alzheimer's disease highlights the involvement of different cortical networks

    Energy Technology Data Exchange (ETDEWEB)

    Varrone, Andrea; Pappata, Sabina; Quarantelli, Mario; Alfano, Bruno [Biostructure and Bioimaging Institute, National Research Council, Via S. Pansini 5, 80131 Napoli (Italy); Caraco, Corradina [Institute of Experimental Medicine and Biotechnology, Piano Lago Mangone (Cosenza) (Italy); Soricelli, Andrea [Faculty of Motor Sciences, University ' ' Parthenope' ' , Napoli (Italy); Milan, Graziella; Postiglione, Alfredo [Department of Clinical and Experimental Medicine, University ' ' Federico II' ' of Napoli (Italy); Salvatore, Marco [Department of Biomorphological and Functional Sciences, University ' ' Federico II' ' of Napoli (Italy)

    2002-11-01

    Characteristic patterns of regional cerebral blood flow (rCBF) reduction, as detected by technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) single-photon emission tomography (SPET), may help clinicians in differentiating patients with frontotemporal dementia (FTD) from those with Alzheimer's disease (AD). However, in some cases these patients may share common rCBF abnormalities and the visual analysis and/or the region of interest (ROI) approach may not sensitively detect more localised focal changes that could be more specific for each pathology. Recently, automated voxel-by-voxel statistical analysis of perfusion brain maps has been applied to SPET images. This method has the advantage of including the rCBF information for the whole brain for statistical analysis without any a priori hypothesis regarding the regions possibly involved. This could result in a better characterisation of rCBF differences in brain regions while also reducing the operator's subjectivity and the time required for data analysis. The purpose of this study was to apply such a technique to highlight the specific brain areas showing a relative functional involvement in FTD and AD. Thus, we compared the relative rCBF patterns obtained in eight FTD patients with those obtained in 21 AD patients using {sup 99m}Tc-HMPAO SPET and statistical parametric mapping (SPM). When FTD patients were compared with AD patients, relatively lower rCBF was observed in right medial frontal cortex (BA 8, 9, 10), right anterior cingulate cortex (BA 32), right temporal cortex (BA 21/22), right orbitofrontal cortex (BA 11) and ventrolateral prefrontal cortex (BA 47); in BA 47 the reduction was evident bilaterally but was more marked on the right side. On the other hand, when AD patients were compared with FTD patients, a significant relative rCBF decrease was found in the bilateral superior parietal cortex (BA 7); this decrease was more extensive on the left side, where it also included the

  7. Mapping blood flow directionality in the human brain.

    Science.gov (United States)

    Park, Sung-Hong; Do, Won-Joon; Choi, Seung Hong; Zhao, Tiejun; Bae, Kyongtae Ty

    2016-07-01

    Diffusion properties of tissue are often expressed on the basis of directional variance, i.e., diffusion tensor imaging. In comparison, common perfusion-weighted imaging such as arterial spin labeling yields perfusion in a scalar quantity. The purpose of this study was to test the feasibility of mapping cerebral blood flow directionality using alternate ascending/descending directional navigation (ALADDIN), a recently-developed arterial spin labeling technique with sensitivity to blood flow directions. ALADDIN was applied along 3 orthogonal directions to assess directional blood flow in a vector form and also along 6 equally-spaced directions to extract blood flow tensor matrix (P) based on a blood flow ellipsoid model. Tensor elements (eigenvalues, eigenvectors, etc) were calculated to investigate characteristics of the blood flow tensor, in comparison with time-of-flight MR angiogram. While the directions of the main eigenvectors were heterogeneous throughout the brain, regional clusters of blood flow directionality were reproducible across subjects. The technique could show heterogeneous blood flow directionality within and around brain tumor, which was different from that of the contralateral normal side. The proposed method is deemed to provide information of blood flow directionality, which has not been demonstrated before. The results warrant further studies to assess changes in the directionality map as a function of scan parameters, to understand the signal sources, to investigate the possibility of mapping local blood perfusion directionality, and to evaluate its usefulness for clinical diagnosis.

  8. The effect of hyperosmotic solutions on the hepatic blood flow

    DEFF Research Database (Denmark)

    Winkler, K; Henriksen, Jens Henrik Sahl; Tygstrup, N

    1993-01-01

    The present study was undertaken in order to measure the effect of hyperosmotic solutions on portal and hepatic blood flow. In five anaesthetized pigs without arterial blood supply to the liver, portal blood flow rate was measured (electromagnetic flowmeter) during 5 min lasting intravenous infus...... for these osmotic effects are not known, but they have to be taken into consideration in studies of the portal and hepatic blood flow.......The present study was undertaken in order to measure the effect of hyperosmotic solutions on portal and hepatic blood flow. In five anaesthetized pigs without arterial blood supply to the liver, portal blood flow rate was measured (electromagnetic flowmeter) during 5 min lasting intravenous...

  9. Cerebral blood flow simulations in realistic geometries

    Directory of Open Access Journals (Sweden)

    Szopos Marcela

    2012-04-01

    Full Text Available The aim of this work is to perform the computation of the blood flow in all the cerebral network, obtained from medical images as angiographies. We use free finite elements codes as FreeFEM++. We first test the code on analytical solutions in simplified geometries. Then, we study the influence of boundary conditions on the flow and we finally perform first computations on realistic meshes. L’objectif est ici de simuler l’écoulement sanguin dans tout le réseau cérébral (artériel et veineux obtenu à partir d’angiographies cérébrales 3D à l’aide de logiciels d’éléments finis libres, comme FreeFEM++. Nous menons d’abord une étude détaillée des résultats sur des solutions analytiques et l’influence des conditions limites à imposer dans des géométries simplifiées avant de travailler sur les maillages réalistes.

  10. Are there adaptive changes in the human brain of patients with Parkinson's disease treated with long-term deep brain stimulation of the subthalamic nucleus? A 4-year follow-up study with regional cerebral blood flow SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Sestini, Stelvio; Castagnoli, Antonio [Ospedale Misericordia e Dolce, Department of Diagnostic Imaging, Nuclear Medicine Unit, Prato (Italy); Pupi, Alberto [University of Florence, Department of Clinical Physiopathology, Nuclear Medicine Unit, Florence (Italy); Ammannati, Franco; Silvia, Ramat; Sorbi, Sandro [University of Florence, Department of Neurological and Psychiatric Sciences, Florence (Italy)

    2007-10-15

    The aim of this follow-up study was to assess persistent motor and regional cerebral blood flow (rCBF) changes in patients with Parkinson's disease (PD) treated with high-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN). Ten PD patients with STN-DBS underwent three rCBF SPECT studies at rest, once preoperatively in the off-drug condition (T{sub 0}), and twice postoperatively in the off-drug/off-stimulation conditions at 5 {+-} 2 (T{sub 1}) and 42 {+-} 7 months (T{sub 2}). Patients were assessed using the UPDRS, H and Y and S and E scales. SPM was used to investigate baseline rCBF changes from the preoperative condition to the postoperative conditions and the relationship between rCBF and UPDRS scores used as covariate of interest. Parkinsonian patients showed a clinical improvement which was significant only on follow-up at 42 months. The main effect of treatment from T{sub 0} to T{sub 1} was to produce baseline rCBF increases in the pre-supplementary motor area (pre-SMA), premotor cortex and somatosensory association cortex. From T{sub 1} to T{sub 2} a further baseline rCBF increase was detected in the pre-SMA (p < 0.0001). A correlation was detected between the slight improvement in motor scores and the rCBF increase in the pre-SMA (p < 0.0001), which is known to play a crucial role in clinical progression. Our study suggests the presence of adaptive functional changes in the human brain of PD patients treated with long-term STN-DBS. Such adaptive processes seem to occur in the pre-SMA and to play only a slightly beneficial role in terms of functional compensation of motor impairment. (orig.)

  11. Dynamic Effect of Rolling Massage on Blood Flow

    Institute of Scientific and Technical Information of China (English)

    CHEN Yan-Yan; YI Hou-Hui; LI Hua-Bing; FANG Hai-Ping

    2009-01-01

    The Chinese traditional medical massage has been used as a natural therapy to eliminate some diseases.Here, the effect of the rolling massage frequency to the blood flow in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation.The simulation results show that when the frequency is smaller than or comparable to the putsatile frequency of the blood flow, the effect on the blood flux by the rolling massage is small.On the contrast, if the frequency is twice or more times of the putsatile frequency of the blood flow, the blood flux is greatly enhanced and increases linearly with respect to the frequency.Similar behavior has also been observed on the shear stress on the blood vessel waits.The result is helpful for understanding that the rolling massage has the function of promoting the blood circulation and removing the blood stasis.

  12. Dynamic Effect of Rolling Massage on Blood Flow

    Science.gov (United States)

    Chen, Yan-Yan; Yi, Hou-Hui; Li, Hua-Bing; Fang, Hai-Ping

    2009-02-01

    The Chinese traditional medical massage has been used as a natural therapy to eliminate some diseases. Here, the effect of the rolling massage frequency to the blood flow in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulation results show that when the frequency is smaller than or comparable to the pulsatile frequency of the blood flow, the effect on the blood flux by the rolling massage is small. On the contrast, if the frequency is twice or more times of the pulsatile frequency of the blood flow, the blood flux is greatly enhanced and increases linearly with respect to the frequency. Similar behavior has also been observed on the shear stress on the blood vessel walls. The result is helpful for understanding that the rolling massage has the function of promoting the blood circulation and removing the blood stasis.

  13. Multiscale modeling of blood flow: from single cells to blood rheology.

    Science.gov (United States)

    Fedosov, Dmitry A; Noguchi, Hiroshi; Gompper, Gerhard

    2014-04-01

    Mesoscale simulations of blood flow, where the red blood cells are described as deformable closed shells with a membrane characterized by bending rigidity and stretching elasticity, have made much progress in recent years to predict the flow behavior of blood cells and other components in various flows. To numerically investigate blood flow and blood-related processes in complex geometries, a highly efficient simulation technique for the plasma and solutes is essential. In this review, we focus on the behavior of single and several cells in shear and microcapillary flows, the shear-thinning behavior of blood and its relation to the blood cell structure and interactions, margination of white blood cells and platelets, and modeling hematologic diseases and disorders. Comparisons of the simulation predictions with existing experimental results are made whenever possible, and generally very satisfactory agreement is obtained.

  14. EFFECT OF INCREASED WHOLE-BLOOD VISCOSITY ON REGIONAL BLOOD FLOWS IN CHRONICALLY HYPOXEMIC LAMBS

    NARCIS (Netherlands)

    DALINGHAUS, M; KNOESTER, H; GRATAMA, JWC; VANDERMEER, J; ZIJLSTRA, WG; KUIPERS, JRG

    1994-01-01

    In chronic hypoxemia blood flow and oxygen supply to vital organs are maintained, but to nonvital organs they are decreased. We measured organ blood flows (microspheres) and whole blood viscosity in 10 chronically hypoxemic lambs, with an atrial septal defect and pulmonary stenosis, and in 8 control

  15. The relationship between cerebral blood flow and volume in humans

    DEFF Research Database (Denmark)

    Rostrup, Egill; Knudsen, Gitte M; Law, Ian;

    2005-01-01

    The purpose of this study was to establish the relationship between regional CBF and CBV at normal, resting cerebral metabolic rates. Eleven healthy volunteers were investigated with PET during baseline conditions, and during hyper- and hypocapnia. Values for rCBF and rCBV were obtained using (15...

  16. Prediction of Anomalous Blood Viscosity in Confined Shear Flow

    Science.gov (United States)

    Thiébaud, Marine; Shen, Zaiyi; Harting, Jens; Misbah, Chaouqi

    2014-06-01

    Red blood cells play a major role in body metabolism by supplying oxygen from the microvasculature to different organs and tissues. Understanding blood flow properties in microcirculation is an essential step towards elucidating fundamental and practical issues. Numerical simulations of a blood model under a confined linear shear flow reveal that confinement markedly modifies the properties of blood flow. A nontrivial spatiotemporal organization of blood elements is shown to trigger hitherto unrevealed flow properties regarding the viscosity η, namely ample oscillations of its normalized value [η]=(η-η0)/(η0ϕ) as a function of hematocrit ϕ (η0=solvent viscosity). A scaling law for the viscosity as a function of hematocrit and confinement is proposed. This finding can contribute to the conception of new strategies to efficiently detect blood disorders, via in vitro diagnosis based on confined blood rheology. It also constitutes a contribution for a fundamental understanding of rheology of confined complex fluids.

  17. Regional cerebral blood flow assessed with {sup 99m}Tc-ECD SPET as a marker of progression of mild cognitive impairment to Alzheimer's disease

    Energy Technology Data Exchange (ETDEWEB)

    Encinas, Marta; Juan, Ramon de; Cabranes, Jose Antonio [Department of Nuclear Medicine, Hospital Clinico San Carlos, Martin Lagos s/n, 28040, Madrid (Spain); Marcos, Alberto [Department of Neurology, Hospital Clinico San Carlos, Madrid (Spain); Gil, Pedro [Department of Geriatrics, Hospital Clinico San Carlos, Madrid (Spain); Barabash, Ana; Fernandez, Cristina; Ugarte, Carmen de [Research Unit, Hospital Clinico San Carlos, Madrid (Spain)

    2003-11-01

    Patients diagnosed with mild cognitive impairment (MCI) have a higher risk of developing Alzheimer's disease (AD). However, not all such patients develop this kind of dementia. The purpose of this prospective study was to assess whether regional cerebral blood flow (rCBF) patterns measured with technetium-99m ethyl cysteinate dimer single-photon emission tomography ({sup 99m}Tc-ECD SPET) in patients suffering from MCI are useful in predicting progression to AD. The study group comprised 42 patients who fulfilled MCI criteria according to the International Psychogeriatric Association and the Alzheimer's Disease Cooperative Study. rCBF was calculated in 16 regions of interest (ROIs). All patients were clinically assessed for 1-3 years. Twenty-one developed AD (group I) while the initial diagnosis of MCI was retained in the other 21 (group II). ROC curves were designed, and sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined for each ROI. Compared with group II (MCI), group I (AD) showed a significant reduction of relative blood flow (RBF), ranging from 7% to 10%, in the following areas: right and left prefrontal, right and left frontal, right and left parietal, right and left temporal, right and left frontoparietotemporal and left posterior lateral temporal. Left prefrontal, left frontal and left parietal areas showed sensitivities and specificities higher than 75% and areas below the ROC curve close to 80%. This study shows that RBF patterns in the right and left prefrontal, right and left frontal and left parietal areas are sensitive early markers of progression towards AD. Reduction of rCBF in the medial temporal and anterior lateral temporal cortex has no value as a predictor since it also occurs in patients with MCI who remain stable. (orig.)

  18. Cerebellar blood flow in methylmercury poisoning (Minamata disease)

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M. [Dept. of Radiology, Kumamoto University School of Medicine (Japan); Okajima, T. [Dept. of Neurology, Johnan Hospital, Maihara, Johnan-mochi (Japan); Sato, H. [Dept. of Neurology, Minamata City General Hospital and Medical Centre (Japan)

    2001-04-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

  19. Cerebellar blood flow in methylmercury poisoning (Minamata disease).

    Science.gov (United States)

    Itoh, K; Korogi, Y; Tomiguchi, S; Takahashi, M; Okajima, T; Sato, H

    2001-04-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part.

  20. Regional cerebral blood flow in fibromyalgia

    Energy Technology Data Exchange (ETDEWEB)

    Kwiatek, R.; Barnden, L.; Rowe, C.; McKinnon, J.; Pile, K. [The Queen Elizabeth Hospital , Adelaide, SA (Australia)

    1998-06-01

    Full text: Little is known of the aetiology of fibromyalgia (FM), a condition diagnosed on the basis of widespread chronic pain and multiple tender points. We have used Tc-99m HMPAO SPECT to compare regional cerebral bloodflow (rCBF) in 17 women who fulfill American College of Rheumatology criteria for FM to 22 age, sex and education matched controls. Both Statistical Parametric Mapping (SPM95) and coregistered MRI guided ROI were used for analysis. SPM95 revealed statistically significant hypoperfusion in the pontine tegmentum (p=0.048) and a trend to hypoperfusion in the left putamen (p=0.07). MRI guided ROI placement by an operator blinded to clinical information and the coregistered SPECT images, confirmed significant hypoperfusion of the left thalamus (p<0.0001) and the pontine tegmentum (p=0.001) and revealed trends towards hypoperfusion in the caudate nuclei and right thalamus. These results are consistent with the hypothesis that FM is due to dysfunction of central pain pathways. Spinothalamic neurones are known to be involved in pain perception and there are synapse connections to the thalamus in the gigantocellular part of the medulla and pons

  1. Cerebrospinal fluid and blood flow in mild cognitive impairment and Alzheimer's disease: a differential diagnosis from idiopathic normal pressure hydrocephalus

    Directory of Open Access Journals (Sweden)

    El Sankari Soraya

    2011-02-01

    Full Text Available Abstract Background Phase-contrast magnetic resonance imaging (PC-MRI enables quantification of cerebrospinal fluid (CSF flow and total cerebral blood (tCBF flow and may be of value for the etiological diagnosis of neurodegenerative diseases. This investigation aimed to study CSF flow and intracerebral vascular flow in patients with Alzheimer's disease (AD and patients with amnesic mild cognitive impairment (a-MCI and to compare the results with patients with idiopathic normal pressure hydrocephalus (NPH and with healthy elderly volunteers (HEV. Methods Ten a-MCI and 9 mild AD patients were identified in a comprehensive neurological and neuropsychological assessment. They underwent brain MRI; PC-MRI pulse sequence was performed with the following parameters: two views per segment; flip angle: 25° for vascular flow and 20° for CSF flow; field-of-view (FOV: 14 × 14 mm²; matrix: 256 × 128; slice thickness: 5 mm; with one excitation for exams on the 3 T machine, and 2 excitations for the 1.5 T machine exams. Velocity (encoding sensitization was set to 80 cm/s for the vessels at the cervical level, 10 or 20 cm/s for the aqueduct and 5 cm/s for the cervical subarachnoid space (SAS. Dynamic flow images were analyzed with in-house processing software. The patients' results were compared with those obtained for HEVs (n = 12, and for NPH patients (n = 13, using multivariate analysis. Results Arterial tCBF and the calculated pulsatility index were significantly greater in a-MCI patients than in HEVs. In contrast, vascular parameters were lower in NPH patients. Cervical CSF flow analysis yielded similar values for all four populations. Aqueductal CSF stroke volumes (in μl per cardiac cycle were similar in HEVs (34 ± 17 and AD patients (39 ± 18. In contrast, the aqueductal CSF was hyperdynamic in a-MCI patients (73 ± 33 and even more so in NPH patients (167 ± 89. Conclusion Our preliminary data show that a-MCI patients present with high systolic

  2. Subcutaneous blood flow during insulin-induced hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Madsbad, S; Sestoft, L

    1982-01-01

    Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptoms...... compared with pre-hypoglycaemic flow. Two hours after onset of hypoglycaemic symptoms, subcutaneous blood flow was still significantly decreased compared with pre-hypoglycaemic flow. In normal subjects local nerve blockade had no effect on blood flow changes during hypoglycaemia, whereas local alpha......-receptor blockade abolished the vasoconstrictor response. We suggest that circulating catecholamines stimulating vascular alpha-receptors are probably responsible for flow reduction in the subcutaneous tissue during hypoglycaemia....

  3. Pulsatile blood flow in Abdominal Aortic Aneurysms

    Science.gov (United States)

    Salsac, Anne-Virginie; Lasheras, Juan C.; Singel, Soeren; Varga, Chris

    2001-11-01

    We discuss the results of combined in-vitro laboratory measurements and clinical observations aimed at determining the effect that the unsteady wall shear stresses and the pressure may have on the growth and eventual rupturing of an Abdominal Aortic Aneurysm (AAA), a permanent bulging-like dilatation occurring near the aortic bifurcation. In recent years, new non-invasive techniques, such as stenting, have been used to treat these AAAs. However, the development of these implants, aimed at stopping the growth of the aneurysm, has been hampered by the lack of understanding of the effect that the hemodynamic forces have on the growth mechanism. Since current in-vivo measuring techniques lack the precision and the necessary resolution, we have performed measurements of the pressure and shear stresses in laboratory models. The models of the AAA were obtained from high resolution three-dimensional CAT/SCANS performed in patients at early stages of the disease. Preliminary DPIV measurements show that the pulsatile blood flow discharging into the cavity of the aneurysm leads to large spikes of pressure and wall shear stresses near and around its distal end, indicating a possible correlation between the regions of high wall shear stresses and the observed location of the growth of the aneurysm.

  4. Synthetic Capillaries to Control Microscopic Blood Flow

    Science.gov (United States)

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-02-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function.

  5. Blood Flow Restricted Exercise and Vascular Function

    Directory of Open Access Journals (Sweden)

    Masahiro Horiuchi

    2012-01-01

    Full Text Available It is established that regular aerobic training improves vascular function, for example, endothelium-dependent vasodilatation and arterial stiffness or compliance and thereby constitutes a preventative measure against cardiovascular disease. In contrast, high-intensity resistance training impairs vascular function, while the influence of moderate-intensity resistance training on vascular function is still controversial. However, aerobic training is insufficient to inhibit loss in muscular strength with advancing age; thus, resistance training is recommended to prevent sarcopenia. Recently, several lines of study have provided compelling data showing that exercise and training with blood flow restriction (BFR leads to muscle hypertrophy and strength increase. As such, BFR training might be a novel means of overcoming the contradiction between aerobic and high-intensity resistance training. Although it is not enough evidence to obtain consensus about impact of BFR training on vascular function, available evidences suggested that BFR training did not change coagulation factors and arterial compliance though with inconsistence results in endothelial function. This paper is a review of the literature on the impact of BFR exercise and training on vascular function, such as endothelial function, arterial compliance, or other potential factors in comparison with those of aerobic and resistance training.

  6. Diagnosis of regional cerebral blood flow abnormalities using SPECT: agreement between individualized statistical parametric maps and visual inspection by nuclear medicine physicians with different levels of expertise in nuclear neurology

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Euclides Timoteo da, E-mail: euclidestimoteo@uol.com.b [Fundacao Pio XII, Barretos, SP (Brazil). Hospital de Cancer. Dept. de Medicina Nuclear; Buchpiguel, Carlos Alberto [Hospital do Coracao, Sao Paulo, SP (Brazil). Dept. de Medicina Nuclear; Nitrini, Ricardo [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Tazima, Sergio [Hospital Alemao Oswaldo Cruz (HAOC), Sao Paulo, SP (Brazil). Dept. de Medicina Nuclear; Peres, Stela Verzinhase [Fundacao Pio XII, Barretos, SP (Brazil). Hospital de Cancer; Busatto Filho, Geraldo [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Div. de Medicina Nuclear

    2009-07-01

    Introduction: visual analysis is widely used to interpret regional cerebral blood flow (rCBF) SPECT images in clinical practice despite its limitations. Automated methods are employed to investigate between-group rCBF differences in research studies but have rarely been explored in individual analyses. Objectives: to compare visual inspection by nuclear physicians with the automated statistical parametric mapping program using a SPECT dataset of patients with neurological disorders and normal control images. Methods: using statistical parametric mapping, 14 SPECT images from patients with various neurological disorders were compared individually with a databank of 32 normal images using a statistical threshold of p<0.05 (corrected for multiple comparisons at the level of individual voxels or clusters). Statistical parametric mapping results were compared with visual analyses by a nuclear physician highly experienced in neurology (A) as well as a nuclear physician with a general background of experience (B) who independently classified images as normal or altered, and determined the location of changes and the severity. Results: of the 32 images of the normal databank, 4 generated maps showing rCBF abnormalities (p<0.05, corrected). Among the 14 images from patients with neurological disorders, 13 showed rCBF alterations. Statistical parametric mapping and physician A completely agreed on 84.37% and 64.28% of cases from the normal databank and neurological disorders, respectively. The agreement between statistical parametric mapping and ratings of physician B were lower (71.18% and 35.71%, respectively). Conclusion: statistical parametric mapping replicated the findings described by the more experienced nuclear physician. This finding suggests that automated methods for individually analyzing rCBF SPECT images may be a valuable resource to complement visual inspection in clinical practice. (author)

  7. 抑郁症患者局部脑血流灌注变化研究%Detection of cerebral blood flow with single emission computed tomography in depressive patients

    Institute of Scientific and Technical Information of China (English)

    余俊丽; 焦举; 许杰华; 程木华; 张峰; 张勇

    2009-01-01

    目的 分析抑郁症患者单光子发射型计算机断层显像(SPECT)局部脑血流(SCBF)灌注变化的特点,并初步探讨rCBF显像在抑郁症患者中的诊断价值. 方法 对10例正常人及临床诊断为抑郁症的32例患者分别进行SPECT局部脑血流灌注显像,利用感兴趣区(ROI)法观察rCBF情况;11例患者同期行MRI普通扫描.结果 32例抑郁症患者中31例发现rCBF显像异常,共检出71个病灶,分别位于双侧额叶、颞叶、基底节、海马、扣带回及左侧岛叶,其中57个病灶位于颞叶、海马、扣带回及岛叶,即边缘系统,9个病灶位于额叶,5个病灶位于基底节;基底节区病灶局部脑血流灌注均增高,其他部位病灶均降低;双侧大脑半球rCBF病灶构成比差异无统计学意义(χ~2=409,P=0.790).11例患者同期做MRI扫描,3例发现异常(2例轻度脑萎缩,1例海马萎缩),而此11例患者rCBF显像均发现异常.1例正常人rCBF未发现异常显像.结论 大多数抑郁症患者存在脑边缘系统rCBF降低,部分患者存在基底节区rCBF增高.SPECT能敏感地发现抑郁症患者rCBF灌注的变化,对抑郁症的诊断具有一定的价值.%Objective To analyze the changes of regional cerebral blood flow (rCBF) with SPECT in depressive patients, and explore the diagnosis value of rCBF imaging for depression. Methods The rCBF imaging was detected by single emission computed tomography (SPECT) on 32 depressive patients and 10 normal subjects, and the characteristics of rCBF changes were assessed with a region-of-interest (ROI) technique. Normal MRI scans were conducted on 11 patients at the same stage. Results Abnormal rCBF was showed in 31 patients with 71 focuses that were located in the bilateral frontal lobe (9), the basal ganglia (5) and the limbic system (57), including the temporal lobe, the hippocampus, the cingulated gyms and the left insular cortex. All abnormalities presented a decreased rCBF except the basal ganglia. No

  8. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...

  9. Blood flow velocity in migraine attacks - a transcranial Doppler study

    Energy Technology Data Exchange (ETDEWEB)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D. (Rijksuniversiteit Leiden (Netherlands))

    1991-05-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs.

  10. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions...

  11. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubula...

  12. Data adaptive estimation of transversal blood flow velocities

    DEFF Research Database (Denmark)

    Pirnia, E.; Jakobsson, A.; Gudmundson, E.

    2014-01-01

    , posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also...... the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques....

  13. Micro-PIV measurements of blood flow in extraembryonic blood vessels of chicken embryos.

    Science.gov (United States)

    Lee, Jung Yeop; Ji, Ho Seong; Lee, Sang Joon

    2007-10-01

    The hemodynamic characteristics of blood flow are important in the diagnosis of circulatory diseases, since such diseases are related to wall shear stress of cardiovascular vessels. In chicken embryos at early stages of development, it is possible to directly visualize blood flow inside blood vessels. We there