Abnormal volumetric brain morphometry and cerebral blood flow in adolescents with depression

BACKGROUND Prior research has demonstrated that the brains of adolescents with depression exhibit distinct structural alterations.However,preliminary studies have documented the pathophysiological changes in certain brain regions,such as the cerebellum,highlighting a need for further research to support the current understanding of this disease.AIM To study brain changes in depressed adolescents.METHODS This study enrolled 34 adolescents with depression and 34 age-,sex-,and education-level-matched healthy control(HC)individuals.Structural and functional alterations were identified when comparing the brains of these two participant groups through voxel-based morphometry and cerebral blood flow(CBF)analysis,respectively.Associations between identified brain alterations and the severity of depressive symptoms were explored through Pearson correlation analyses.RESULTS The cerebellum,superior frontal gyrus,cingulate gyrus,pallidum,middle frontal gyrus,angular gyrus,thalamus,precentral gyrus,inferior temporal gyrus,superior temporal gyrus,inferior frontal gyrus,and supplementary motor areas of adolescents with depression showed an increase in brain volume compared to HC individuals.These patients with depression further presented with a pronounced drop in CBF in the left pallidum(group=98,and peak t=-4.4324),together with increased CBF in the right percental gyrus(PerCG)(group=90,and peak t=4.5382).In addition,17-item Hamilton Depression Rating Scale scores were significantly correlated with the increased volume in the opercular portion of the left inferior frontal gyrus(r=-0.5231,P<0.01).CONCLUSION The right PerCG showed structural and CBF changes,indicating that research on this part of the brain could offer insight into the pathophysiological causes of impaired cognition.

Hyperbaric oxygen therapy for cerebral blood flow and electroencephalogram in patients with acute cerebral infarction Choice for therapeutic occasion

BACKGROUND： Hyperbaric oxygen （HBO） therapy increases blood oxygen content, changes cerebral blood flow （CBF） and cerebral metabolism. Its therapeutic effects on cerebrovascular disease have been fully confirmed, but the occasion for HBO therapy is still unclear. OBJECTIVE： To observe the therapeutic effects of HBO therapy at different time on CBF and electroencephalogram （EEG） in patients with acute cerebral infarction （CI）. DESIGN： Randomized controlled trial. SETTING： Department of Neurology, Shidong Hospital, Yangpu District of Shanghai. PARTICIPANTS： Ninety-six inpatients with acute CI, admitted to Department of Neurology, Shidong Hospital, Yangpu District of Shanghai from January 2001 to December 2006, were involved in this experiment. The involved participants met the diagnosis criteria of acute CI and confirmed by skull CT or MRI. They all were patients with moderate CI （16- 30 points） according to neurologic deficit score formulated by Chinese Medical Association. Informed consents of detected items and therapeutic regimen were obtained from all the involved participants. They were randomized into two groups with 48 in each： early-stage treatment group and advanced-stage treatment group. Among the 48 patients in the early-stage treatment group, 21 male and 27 female, aged 53 -68 years, 22 patients were found with basal ganglia infarction, 10 with brain lobe infarction, 16 with multiple infarction, 27 accompanied with hypertension and 2 accompanied with diabetes meUitus. Among the 48 patients in the advanced-stage treatment group, 23 male and 25 female, aged 52 - 71 years, 25 patients were found with basal ganglia infarction, 10 with brain lobe infarction, 12 with multiple infarction, 1 with brain stem infarction, 28 accompanied with hypertension and 1 accompanied with diabetes mellitus. METHODS： After admission, patients of two groups received routine drug treatment. ① Patients in the early-stage treatment group and advanced-stage treatment group began to receive HBO therapy within one week of CI and 4 weeks after CI, respectively. The total course of treatment both was 2 weeks. EEG examination was carried out before and after therapy, and CBF was determined with ^133Xe inhalation.② Assessment criteria of curative effects： Basically cured： neurologic symptoms and body signs disappeared, could work and do housework; Markedly effective： score of neurologic deficit was decreased by over 21 points, could manage himself/herself partially; Effective： score of neurologic deficit was decreased by 8 to 12 points; Non-effective： Score was increased or decreased less than 8 points, neurologic deficit was worsened, even died. Total effective rate = （number of cured＋number of markedly effective＋number of effective）/ number of total cases ×100%. ③ t test and Chi-square test were used for comparing the difference of measurement data and enumeration data respectively, and Ridit analysis was used for comparing the difference of clinical curative effects. MAIN OUTCOME MEASURES： ① Comparison of EEG and CBF of patients from two groups before and after treatment. ②Comparison of post-treatment neurologic deficit of patients between two groups. RESULTS： All the involved 96 patients with CI participated in the final analysis. ① Clinical symptoms of patients from two groups after therapy were significantly improved as compared with those before therapy, and curative effects of early treatment group were better than those of advanced treatment group （ U = 1.99, P 〈 0.05 ） . ②After treatment, CBF in each region of brains, except for that in parietal lobe of patients in the advanced-stage treatment group, was significantly improved （P 〈 0.05 - 0.01）; The improvement of CBF of patients in the early-stage treatment group was more obvious than that in the early-stage treatment group （P 〈 0.05 - 0.01）. ③ The abnormal rate of EEF of patients from early-stage treatment group and advanced-stage treatment group before treatment was 94% and 96%, respectively. After treatment, improvement rate of EEG of patients in the early-stage treatment groulp was 95%, which was significantly different from that in the advanced-stage treatment group （82%, x^2=4.32, P 〈 0.05 ） CONCLUSION： HBO therapy both at early and advanced stages of CI （within 1 week and 4 weeks after CI attack） can improve CBF and EEG of patients with early CI, especially.

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

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

A New Method for Evaluating Regional Cerebral Blood Flow Changes:Laser Speckle Contrast Imaging in a C57BL/6J Mouse Model of Photothrombotic Ischemia

The present study aimed to improve the processing of data acquired from laser speckle contrast imaging（LSCI） to provide a standardization method to explore changes in regional cerebral blood flow（r CBF） and to determine the correlations among r CBF, cerebral ischemic lesion volume and microvascular density over time in a focal ischemic region. C57BL/6J mice were subjected to focal photothrombotic（PT） ischemia. r CBF was measured using LSCI at different time points before and after PT ischemia through an intact skull. Standardized r CBF（Sr CBF）, defined as the ratio of r CBF measured in the ipsilateral region of interest（ROI） to that in the corresponding contralateral region, was calculated to evaluate potential changes. In addition, the volume of the ischemic lesion and the microvascular density were determined using Nissl staining and immunofluorescence, respectively. The relationships among the ischemic lesion volume, microvascular density and Sr CBF were analyzed over time. The results showed that the cortical r CBF measured using LSCI following PT ischemia in the C57BL/6J mice gradually increased. Changes in the cerebral ischemic lesion volume were negatively correlated with Sr CBF in the ischemic region. Changes in the microvascular density were similar to those observed in Sr CBF. Our findings indicate that LSCI is a practical technique for observing changes in murine cortical r CBF without skull opening and for analyzing the relationships among the ischemic lesion volume, microvascular density and Sr CBF following focal cerebral ischemia. Preliminary results also suggest that the use of LSCI to observe the formation of collateral circulation is feasible.

Electroacupuncture induces acute changes in cerebral cortical mi RNA profile, improves cerebral blood flow and alleviates neurological deficits in a rat model of stroke

Electroacupuncture has been shown to improve cerebral blood flow in animal models of stroke. However, it is unclear whether electroacupuncture alters mi RNA expression in the cortex. In this study, we examined changes in the cerebral cortical mi RNA profile, cerebral blood flow and neurological function induced by electroacupuncture in a rat model of stroke. Electroacupuncture was performed at Renzhong（GV26） and Neiguan（PC6）, with a frequency of 2 Hz, continuous wave, current intensity of 3.0 m A, and stimulation time of 1 minute. Electroacupuncture increased cerebral blood flow and alleviated neurological impairment in the rats. mi RNA microarray profiling revealed that the vascular endothelial growth factor signaling pathway, which links cell proliferation with stroke, was most significantly affected by electroacupuncture. Electroacupuncture induced changes in expression of rno-mi R-206-3p, rno-mi R-3473, rno-mi R-6216 and rno-mi R-494-3p, and these changes were confirmed by quantitative real-time polymerase chain reaction. Our findings suggest that changes in cell proliferation-associated mi RNA expression induced by electroacupuncture might be associated with the improved cerebral blood supply and functional recovery following stroke.

REAL-TIME MONITORING OF MITOCHONDRIAL FUNCTION AND CEREBRAL BLOOD FLOW FOLLOWING FOCAL ISCHEMIA IN RATS

Focal ischemia due to reduction of cerebral blood flow(CBF),creates 2 zones of damage:the core area,which suffers severe damage,and penumbra area,which surrounds the core and suffers intermediate levels of injury.Objectives:A novel method is introduced,which evaluates mitochondrial function in the core and in the penumbra,during focal cerebral ischemia.Methods:Wistar rats underwent focal cerebral ischemia by middle cerebral artery occlusion(MCAO)for 60 minutes,followed by 60 minutes of reperfusion.Mitochondrial function was assessed by a unique Multi-Site—Multi-Parametric(MSMP)monitoring system,which measures mitochondrial NADH using fluorometric technique,and CBF using Laser Doppler Flowmetry(LDF).Results:At the onset of occlusion,CBF dropped and NADH increased significantly only in the right hemisphere.CBF levels were significantly lower and NADH significantly higher in the core than in the penumbra.After reperfusion,CBF and NADH recovered correspondingly to the intensity of ischemia.Conclusion:Application of the MSMP system can add significant information for the understanding of the cerebral metabolic state under ischemic conditions,with an emphasis on mitochondrial function.

Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

Characterization of cerebral blood flow dynamics with multiscale entropy

Based on the laser speckle contrast imaging(LSCI)and the multiscale entropy(MSE),we study in this work the blood flow dynamics at the levels of cerebral veins and the surrounding network of microcerebral vessels.We discuss how the phenylephrine-related acute peripheral bypertension is refected in the cerebral circulation and show that the observed changes are scale dependent,and they are signifcantly more pronounced in microcerebral vessels,while the macrocerebral dynamics does not demonstrate authentic inter-group distinctions.We also consider the permeability of blood-brain barrier(BBB)and study its opening caused by sound exposure.We show that alterations associated with the BBB opening can be revealed by the analysis of blood flow at the level of macrocerebral vessels.

Blood-brain barrier and cerebral blood flow: Age differences in hemorrhagic stroke

Neonatal stroke is similar to the stroke that occurs in adults and produces a significant morbidity and long-term neurologic and cognitive deficits.There are important differences in the factors,clinical events and outcomes associated with the stroke in infants and adults.However,mechanisms underlying age differences in the stroke development remain largely unknown.Therefore,treatment guidelines for neonatal stroke must extrapolate from the adult data that is often not suitable for children.The new information about differences between neonatal and adult stroke is essential for identification of significant areas for future treatment and effective prevention of neonatal stroke.Here,we studied the development of stress-induced hemorrhagic stroke and possible mechanisms underlying these processes in newborn and adult rats.Using histological methods and magnetic resonance imaging,we found age differences in the type of intracranial hemorrhages.Newborn rats demonstrated small superficial bleedings in the cortex while adult rats had more severe deep bleedings in the cerebellum.Using Doppler optical coherent tomography,we found higher stress-reactivity of the sagittal sinus to deleterious effects of stress in newborn vs.adult rats suggesting that the cerebral veins are more vulnerable to negative stress factors in neonatal vs.adult brain in rats.However,adult but not newborn rats demonstrated the stroke-induced breakdown of blood brain barrier(BBB)permeability.The one of possible mechanisms underlying the higher resistance to stress-related stroke injures of cerebral vessels in newborn rats compared with adult animals is the greater expression of two main tight junction proteins of BBB(occludin and claudin-5)in neonatal vs.mature brain in rats.

Sufficiently Elevated Core Body Temperature May Be Necessary to Maintain Cerebral Blood Flow Response throughout the Morning

In comparison to a carbohydrate-rich breakfast, a nutritionally balanced breakfast reportedly leads to a higher core body temperature because of diet-induced thermogenesis (DIT) and also results in higher task performance. This study aimed to examine the relationships among the core body temperature, blood glucose level, cerebral blood flow, and cognitive performance when the core body temperature is raised to a similar extent as in DIT in the morning. This crossover study included 18 male participants who performed four sets of cognitive tests in the morning with four different foot baths and glucose intake conditions. In elevated body temperature (EBT) conditions, the core body temperature was increased by a foot bath at 42&#730;C or 39&#730;C, while in low body temperature (LBT) conditions, it was maintained at 35&#730;C by a foot bath;the participants received no glucose or two intakes of 20-g glucose for each thermal condition. In addition to the core body temperature measurement, the cerebral blood flow in the dorsolateral prefrontal cortex (DLPFC) was measured using near-infrared spectroscopy. Three blood collections were performed to measure the changes in blood glucose levels. The results revealed that in the EBT conditions, the core body temperature remained 0.3&#730;C - 0.5&#730;C higher than that at wake-up time, while the glucose intake conditions increased blood glucose levels which remained higher than those during fasting. No significant between-treatment difference was observed in the results of cognitive tests. However, the blood flow in the DLPFC increased during the second test period in the EBT/glucose and LBT/glucose conditions, whereas during the fourth test period, it increased solely in the EBT/glucose condition. Thus, in addition to the blood glucose level, an elevated core body temperature within the physiological range may be needed for long-term maintenance of the cerebral blood flow response.

The effects of decompressive craniectomy on cerebral blood flow volume and brain metabolism in different aged patients with severe traumatic brain injury

Objective To explore effects of decompressive craniectomy on cerebral blood flow volume and brain metabolism in different aged patients with severe traumatic brain injury. Methods 71 cases were divided into three groups according age: group A( 【 30 years) ,group B ( 30 ～ 50 years) 。

Characteristics of traumatic brain injury models:from macroscopic blood flow changes to microscopic mitochondrial changes

Controlled cortical impingement is a widely accepted method to induce traumatic brain injury to establish a traumatic brain injury animal model.A strike depth of 1 mm at a certain speed is recommended for a moderate brain injury and a depth of>2 mm is used to induce severe brain injury.However,the different effects and underlying mechanisms of these two model types have not been proven.This study investigated the changes in cerebral blood flow,differences in the degree of cortical damage,and differences in motor function under different injury parameters of 1 and 2 mm at injury speeds of 3,4,and 5 m/s.We also explored the functional changes and mitochondrial damage between the 1 and 2 mm groups in the acute(7 days)and chronic phases(30 days).The results showed that the cerebral blood flow in the injured area of the 1 mm group was significantly increased,and swelling and bulging of brain tissue,increased vascular permeability,and large-scale exudation occurred.In the 2 mm group,the main pathological changes were decreased cerebral blood flow,brain tissue loss,and cerebral vasospasm occlusion in the injured area.Substantial motor and cognitive impairments were found on day 7 after injury in the 2 mm group;at 30 days after injury,the motor function of the 2 mm group mice recovered significantly while cognitive impairment persisted.Transcriptome sequencing showed that compared with the 1 mm group,the 2 mm group expressed more ferroptosis-related genes.Morphological changes of mitochondria in the two groups on days 7 and 30 using transmission electron microscopy revealed that on day 7,the mitochondria in both groups shrank and the vacuoles became larger;on day 30,the mitochondria in the 1 mm group became larger,and the vacuoles in the 2 mm group remained enlarged.By analyzing the proportion of mitochondrial subgroups in different groups,we found that the model mice had different patterns of mitochondrial composition at different time periods,suggesting that the difference in the degree of damage among traumatic brain injury groups may reflect the mitochondrial changes.Taken together,differences in mitochondrial morphology and function between the 1 and 2 mm groups provide a new direction for the accurate classification of traumatic brain injury.Our results provide reliable data support and evaluation methods for promoting the establishment of standard mouse controlled cortical impingement model guidelines.

Paeoniflorin Improves Regional Cerebral Blood Flow and Suppresses Inflammatory Factors in the Hippocampus of Rats with Vascular Dementia

Objective： To explore the delayed neuroprotection induced by paeoniflorin（PF）, the principal component of Paeoniae radix prescribed in Chinese medicine, and its underlying mechanisms in rats subjected to vascular dementia（VD）. Methods： A rat model of VD was induced by bilateral common carotid arteries occlusion（BCCAO）. Low-dose or high-dose PF（20 or 40 mg/kg once per day） was administrated for 28 days after VD. The behavioral analysis of rat was measured by water morris. Regional cerebral blood volume（r CBV）, regional cerebral blood flow（r CBF） and mean transit time（MTT） were measured in the bilateral hippocampus by perfusion-weighted imaging（PWI）. The levels of interleukin-1β（IL-1β）, interleukin-6（IL-6）, and tumor necrosis factor alpha（TNF-α） were measured by commercially available enzyme-linked immunosorbent assay kits. Protein levels were evaluated by western blot analysis. m RNA levels were evaluated by real time-polymerase chain reaction. Western blotting was used to estimate p65 translocation. Results： The behavioral analysis showed that PF could decrease the escape latency time（P〈0.05）, and increase the residence time of the original platform quadrant and the across platform frequency in water maze in VD rats（P〈0.05）. Likewise, PF remarkably promoted the r CBV（P〈0.05）, r CBF and decreased per minute MTT（P〈0.05） in hippocampus of VD rats. Furthermore, PF decreased the release of IL-1β, IL-6 and TNF-α as well as inhibited the m RNA expression of IL-1β, IL-6 and TNF-α in the hippocampus of VD rats（P〈0.05 or P〈0.01）. PF also could decrease the protein expressions of inducible nitric oxide synthase and cyclooxygenase-2 in the hippocampus of VD rats（P〈0.05 or P〈0.01）. In addition, PF significantly inhibited the nuclear factor κB（NF-κB） pathway in the hippocampus of VD rats. Conclusions： PF significantly attenuates cognitive impairment, improves hippocampus perfusion and inhibits inflammatory response in VD rats. In addition, the anti-inflammatory effects of PF might be due to inhibiting the NF-κB pathway. PF may be a potential clinical application in improving VD.

Compromised cerebrovascular modulation in chronic anxiety:evidence from cerebral blood flow velocity measured by transcranial Doppler sonography

Objective Cerebral autoregulation （CA） is the mechanism by which constant cerebral blood flow is maintained despite changes in cerebral perfusion pressure. CA can be evaluated by dynamic monitoring of cerebral blood flow velocity （CBFV） with transcranial Doppler sonography （TCD）. The present study aimed to explore CA in chronic anxiety. Methods Subjects with Hamilton anxiety scale scores 〉14 were enrolled and the dynamic changes of CBFV in response to an orthostatic challenge were investigated using TCD. Results In both the anxious and the healthy subjects, the mean CBFV was significantly lower in the upright position than when supine. However, the CBFV changes from supine to upright differed between the anxious and the healthy groups. Anxious subjects showed more pronounced decreases in CBFV with abrupt standing. Conclusion Our results indicate that cerebrovascular modulation is compromised in chronic anxiety; anxious subjects have some insufficiency in maintaining cerebral perfusion after postural change. Given the fact that anxiety and impaired CA are associated with cardiovascular disease, early ascertainment of compromised cerebrovascular modulation using TCD might suggest interventional therapies in the anxious population, and improve the primary prevention of cardiovascular disease.

Regional cerebral blood flow in children with autism spectrum disorders： a quantitative 99mTc-ECD brain SPECT study with statistical parametric mapping evaluation

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 group, and in the bilateral cerebellum （22.8%）, basal nucleus （19.3%） and right thalamencephalon （16.6%）in the AS group （P ＜0.05）.Conclusions The decrease in rCBF in ASD is a global event, which involves the bilateral frontal, temporal, limbic system and basal ganglias. Asymmetry of hemispheric hypoperfusion was more obvious in the AS group than the autism group, which indicates a different neurobiological mechanism from that of autism.

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

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 risk of 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）; it was （417.72±21.35） PU on the 1st day after surgery, and （358.99±18.01） PU, （323.46±17.38） PU, （261.60±16.38） PU and （375.72±18.45） PU on the following 4 days, respectively. The rCBF decreased gradually from the 2nd day until the 4th postoperative day, but still was at a high level （P 〈0.05）. However, on the 5th postoperative day the rCBF increased again to the second highest level, which was significantly different compared with the baseline value （P 〈0.05）, but not significantly different compared with the values on the other 4 days （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.

Measurements Of Cerebral Blood Flow in Postasphyxiated Newborns by Color Doppler Imaging（CDI）

Cerebral blood flow of 10 asphyxiated term newborns was continuously measured during the first 7 days of life and compared with that of 10 normal term infants by CDI. Frequency spectrum and blood flow variables in the anterior, middle and posterior cerebral arteries were studied. The results showed evidently lower systolic amplitude in patients than that in normal subjects. End diastolic amplitude was zero in part of vessels, and values of bloed flow variables were all lower in day 1 of the life as compared with the control groups. Frequency spectrum recovered to normal patterns in 9 survived infants in day 2. but blood flow variables recovered to normal by day 7. Values of resistance index (RI) rose to 1 in some vessels of moderate hypoxic ischemic encephalopathy (HIE) infants and stayed at 1 in the severe HIE infants. It is concluded that low CBF plays a key role in brain damage of post-asphyxiated newborns and RI may be an important parameter in the evaluation prognosis.

Xenon-enhanced CT assessment of cerebral blood flow in stroke-in-progress patients with unilateral internal carotid artery or middle cerebral artery stenosis

Carotid or cerebral artery stenosis resulting in low perfusion is a major cause of ischemic stroke.Understanding the unique hemodynamic features in each patient undergoing a stroke-in-progress（SIP） and the correlation between progression and cerebral blood flow（CBF） status would help in the diagnosis and treatment of individual patients.We used xenonenhanced CT（Xe-CT） to examine cerebral perfusion in patients with or without SIP（30 patients/group）,recruited from October 2009 to October 2010.Only SIP patients with unilateral stenosis in the internal or middle cerebral artery were recruited.The occurrence of watershed infarction was higher in the SIP group than in the non-SIP group（P ＆lt;0.05）.In the SIP group,larger hypoperfused areas were found around the lesions than in the non-SIP group.In the SIP group,the CBF values in the ipsilateral areas were significantly lower than those in corresponding regions on the contralateral side.CBF values in the contralateral hemisphere were significantly lower in the SIP group than in the non-SIP group.In SIP patients,infarctions were surrounded by larger hypoperfused areas than in non-SIP patients.These larger hypoperfused areas may result in pathological damage to the brain that is responsible for the progression of stroke.

Laser speckle imaging and wavelet analysis of cerebral blood flow associated with the opening of the blood–brain barrier by sound

The cerebral blood flow（CBF） alterations related to sound-induced opening of the blood–brain barrier（BBB） in adult mice are studied using laser speckle contrast imaging（LSCI） and wavelet analysis of vascular physiology.The results clearly show that the opening of the BBB is accompanied by the changes of venous but not microvessel circulation in the brain. The elevation of the BBB permeability is associated with the decrease of venous CBF and the increase of its complexity. These data suggest that the cerebral veins rather than microvessels are sensitive components of the CBF related to the opening BBB.

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

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 rCBE Results The mean CBF values were （122±28） ml·（100g）^-1· min^-1 and （43± 10） ml·（100g）^-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 rCBE but different imaging slice may affect the agreement of rCBF across the scans.