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Cerebral Perfusion (cerebral + perfusion)
Kinds of Cerebral Perfusion Terms modified by Cerebral Perfusion Selected AbstractsNoninvasive Control of Adequate Cerebral Oxygenation During Low-Flow Antegrade Selective Cerebral Perfusion on Adults and Infants in the Aortic Arch SurgeryJOURNAL OF CARDIAC SURGERY, Issue 5 2008Álvaro Rubio M.D. Background: Aortic arch repair techniques using low-flow antegrade selective cerebral perfusion have been standardized to a certain degree. However, some of the often-stated beneficial effects have never been proven. Especially, the existence of an adequate continuous flow in both cerebral hemispheres during the surgical procedure still remains unclear as the monitoring of an effective perfusion remains a nonstandardized technique. Methods: Seventeen patients underwent surgical reconstruction of the aortic arch due to aortic aneurysm surgery (adult group n = 8 patients) or of the hypoplastic aortic arch due to hypoplastic left heart syndrome (HLHS) or aortic coarctation (infant group n = 9 patients) under general anesthesia and mild hypothermia (adult group 28 °C; infant group 25 °C). Mean weights were 92.75 ± 14.00 kg and 4.29 ± 1.32 kg, and mean ages were 58.25 ± 10.19 years and 55.67 ± 51.11 days in the adult group and the infant group, respectively. The cerebral O2 saturation measurement was performed by continuous plotting of the somatic reflectance oximetry of the frontal regional tissue on both cerebral hemispheres (rSO2, INVOS®; Somanetics Corporation, Troy, MI, USA). Results: During low-flow antegrade perfusion via innominate artery, continuous plots with similar values of O2 saturation (rSO2) in both cerebral hemispheres were observed, whereas a decrease in the rSO2 values below the desaturation threshold correlated with a displacement or an incorrect positioning of the arterial cannula in the right subclavian artery. Conclusions: Continuous monitorization of the cerebral O2 saturation during aortic arch surgery in adults and infants is a feasible technique to control an adequate cannula positioning and to optimize clinical outcomes avoiding neurological complications related to cerebral malperfusion. [source] Is It Safe to Initiate Selective Cerebral Perfusion with Normothermia?JOURNAL OF CARDIAC SURGERY, Issue 5 2005Mizuho Imamaki M.D. Cerebral circulation is isolated from systemic circulation to avoid cerebral embolization due to detachment of atherosclerotic material from the aorta, caused by the "sandblasting" effect of high-velocity jets of blood exiting the aortic cannula. However, neither the safety of SCP at normothermia nor the influence of extended SCP time has been sufficiently clarified. To clarify the safety of P-SCP, the comparison study of P-SCP and conventional SCP (C-SCP) was performed retrospectively. Methods: Fifty-seven patients (C-SCP group: 29 patients; P-SCP: 28 patients) underwent surgery between 1992 and 2002. Results: Nine (15.8%) in-hospital death occurred; 4 in the C-SCP group (13.8%) and 5 in the P-SCP group (17.9%) (NS). The SCP time was 136.6 ± 68.5 minutes in the C-SCP group and 195.8 ± 30.7 minutes in the P-SCP group (p < 0.05). One patient in each group exhibited postoperative neurological dysfunction. Conclusion: It may be little dangerous to initiate the SCP with normothermia. P-SCP may be useful in cases in which there is pedunculated atherosclerotic material, or mural thrombus in the ascending and arch aorta. [source] The Use of Cerebral Oximetry as a Monitor of the Adequacy of Cerebral Perfusion in a Patient Undergoing Shoulder Surgery in the Beach Chair PositionPAIN PRACTICE, Issue 4 2009Gregory W. Fischer MD Abstract Four cases of ischemic injury have been reported in patients undergoing orthopedic surgery in the upright position. We describe the use of cerebral oximetry as a monitor of the adequacy of cerebral perfusion in a 63-year-old woman who underwent arthroscopic rotator cuff surgery in a beach chair under general anesthesia. During positioning, a decrease in blood pressure was accompanied by a decrease in cerebral oxygen saturation (SctO2) and was treated with phenylephrine. When spontaneous ventilation resumed, an increase in end-tidal carbon dioxide was accompanied by an increase in SctO2. Cerebral oximetry may prove useful as a guide monitor and manage nonsupine patients. [source] Optimal Strategy of Selective Cerebral Perfusion During Aortic Arch ConstructionARTIFICIAL ORGANS, Issue 7 2010Bingyang Ji MD No abstract is available for this article. [source] Aortic Arch Surgery With a Single Centrifugal Pump for Selective Cerebral Perfusion and Systemic CirculationARTIFICIAL ORGANS, Issue 1 2010Keiji Iwata Abstract In aortic arch surgery, two pumps are required for systemic perfusion and selective cerebral perfusion (SCP). A new technique with a single centrifugal pump for systemic perfusion and SCP was developed and its efficacy and safety evaluated. This technique was adopted for total arch replacement in 22 consecutive patients with true aneurysms (13) and aortic dissection (nine) from January 2005 to January 2008. Cerebral perfusion lines branched from the main perfusion line. During SCP, right radial arterial pressure was maintained at 50 mm Hg and left common carotid arterial pressure at 60 mm Hg, and the regional cerebral oxygen saturation (rSO2) values were maintained at approximately >80% of the baseline value. Two operative deaths (9%) occurred due to pneumonia and hemorrhage in the left lung, respectively. Stroke occurred in one patient (5%). This simple circuit system can thus be easily and safely applied for aortic arch surgery. [source] Cerebral perfusion in the elderly with nocturnal blood pressure fallEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2007A. Siennicki-Lantz Cerebrovascular disease may be linked with vascular autoregulation in aging. The aim of this study was to examine relation between nocturnal blood pressure (BP) fall and cerebral blood flow (CBF) changes in elderly men. The prospective ,Men born in 1914' cohort study has been in progress since 1968 and included 809 subjects. After 14 years from the last follow up, 97 subjects reached the age of 82 and underwent CBF measurement and 24 h ambulatory blood pressure monitoring. Diastolic BP at night decreased in 84 subjects with median 12.7% and increased in 13 subjects with median 3.7%. Relative diastolic BP fall at night was negatively associated to CBF in temporal and infero-parietal areas. Higher proportion of subjects with increasing systolic BP during the 14-year period was observed in the subgroup with extreme nocturnal diastolic BP dip, irrespectively of BP values or prevalence of hypertension. Extreme nocturnal diastolic BP fall in a cohort of elderly men is correlated with focal changes in CBF. Further studies could explain if increasing BP in the elderly is a cause or result of pathological autoregulation, and if antihypertensive treatment increases nocturnal BP dip. [source] Transcranial Doppler Blood Flow Assessment in Patients With Mild Heart Failure: Correlates With Neuroimaging and Cognitive PerformanceCONGESTIVE HEART FAILURE, Issue 2 2008Raymond L. C. Vogels MD Cardiac output and cerebral perfusion are reduced in patients with advanced stages of heart failure. Our aim was to determine whether cerebral blood flow velocity measured by transcranial Doppler ultrasonography was reduced in outpatients with mild heart failure in comparison to controls and, if so, whether this reduction was related to cognitive performance and abnormalities of the brain diagnosed by magnetic resonance imaging. [source] Cerebral oxygenation decreases during exercise in humans with beta-adrenergic blockadeACTA PHYSIOLOGICA, Issue 3 2009T. Seifert Abstract Aim:, Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. Methods:, Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. Results:, Arterial lactate and cardiac output increased to 15.3 ± 4.2 mm and 20.8 ± 1.5 L min,1 respectively (mean ± SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 ± 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 ± 6 vs. 69 ± 8 beats min,1) and at exercise exhaustion, cardiac output (16.6 ± 3.6 L min,1) and arterial lactate (9.4 ± 3.7 mm) were attenuated with a reduction in exercise capacity from 239 ± 42 to 209 ± 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 ± 10 mmHg; P < 0.05). Conclusion:, Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity. [source] Cerebral bloodflow and oxygen metabolism in borderzone and territorial infarcts due to symptomatic carotid artery occlusionEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2004J. De Reuck It remains controversial whether borderzone infarcts are due to compromised cerebral perfusion and whether territorial infarcts are caused by artery-to-artery emboli in case of occlusion of the internal carotid artery. The present positron emission tomography study compares with normal controls, the average regional cerebral bloodflow (rCBF), regional oxygen extraction fraction (rOEF) and regional cerebral metabolic rate for oxygen (rCMRO2) in the infarct area, the peri-infarct zone, the remaining homolateral hemisphere and in the contralateral hemisphere of 10 patients with borderzone and 17 patients with territorial infarcts, due to internal carotid artery occlusion by atherosclerosis and by cervical dissection. The steady-state technique with oxygen-15 was used. A nearly significant increase of rOEF with lowered rCBF and rCMRO2 was observed in the peri-infarct zone of patients with territorial infarcts. In patients with borderzone infarcts rCMRO2 was decreased in the peri-infarct zone, in the remaining homolateral hemisphere and in the contralateral hemisphere without changes in rCBF and rOEF. The present study finds no arguments that impaired cerebral perfusion is a more frequent cause of borderzone than of territorial infarcts. [source] Immediate Clinical Outcome after Prolonged Periods of Brain Protection: Retrospective Comparison of Hypothermic Circulatory Arrest, Retrograde, and Antegrade PerfusionJOURNAL OF CARDIAC SURGERY, Issue 5 2009Anil Z. Apaydin M.D. Methods: Between 1993 and 2006, 339 patients underwent proximal aortic operations using a period of cerebral protection. Among these, 161 patients (mean age of 55 ± 12 years) who required cerebral protection longer than 25 minutes were included in the analysis. Ascending aorta with or without root was replaced in all patients. In addition, total arch replacement was performed in 36 patients. All patients were cooled to rectal temperature of 16 °C. Hypothermic circulatory arrest without adjunctive perfusion was used in 48 patients. Retrograde or antegrade cerebral perfusion was added in 94 and 19 patients, respectively. The mean duration of total cerebral protection was 42 ± 17 minutes. Results: Overall mortality was 15.5% (25/161) and did not differ among the perfusion groups. There was no difference in the incidence of overall neurological events, temporary neurological dysfunction, or major stroke among the groups. Multivariate analysis revealed that transfusion of >3 units of blood (p < 0.03) was an incremental risk factor for mortality. History of hypertension (p < 0.03), coexisting systemic diseases (p < 0.005), and transfusion of >3 units of blood (p < 0.04) were predictors of temporary neurological dysfunction. Conclusion: In proximal aortic operations requiring prolonged periods of cerebral protection, the mortality and neurological morbidity are not determined by the type of cerebral protection method only. Factors like hypertension and diabetes may play a role in the development of temporary neurological dysfunction. [source] Noninvasive Control of Adequate Cerebral Oxygenation During Low-Flow Antegrade Selective Cerebral Perfusion on Adults and Infants in the Aortic Arch SurgeryJOURNAL OF CARDIAC SURGERY, Issue 5 2008Álvaro Rubio M.D. Background: Aortic arch repair techniques using low-flow antegrade selective cerebral perfusion have been standardized to a certain degree. However, some of the often-stated beneficial effects have never been proven. Especially, the existence of an adequate continuous flow in both cerebral hemispheres during the surgical procedure still remains unclear as the monitoring of an effective perfusion remains a nonstandardized technique. Methods: Seventeen patients underwent surgical reconstruction of the aortic arch due to aortic aneurysm surgery (adult group n = 8 patients) or of the hypoplastic aortic arch due to hypoplastic left heart syndrome (HLHS) or aortic coarctation (infant group n = 9 patients) under general anesthesia and mild hypothermia (adult group 28 °C; infant group 25 °C). Mean weights were 92.75 ± 14.00 kg and 4.29 ± 1.32 kg, and mean ages were 58.25 ± 10.19 years and 55.67 ± 51.11 days in the adult group and the infant group, respectively. The cerebral O2 saturation measurement was performed by continuous plotting of the somatic reflectance oximetry of the frontal regional tissue on both cerebral hemispheres (rSO2, INVOS®; Somanetics Corporation, Troy, MI, USA). Results: During low-flow antegrade perfusion via innominate artery, continuous plots with similar values of O2 saturation (rSO2) in both cerebral hemispheres were observed, whereas a decrease in the rSO2 values below the desaturation threshold correlated with a displacement or an incorrect positioning of the arterial cannula in the right subclavian artery. Conclusions: Continuous monitorization of the cerebral O2 saturation during aortic arch surgery in adults and infants is a feasible technique to control an adequate cannula positioning and to optimize clinical outcomes avoiding neurological complications related to cerebral malperfusion. [source] Minimized Mortality and Neurological Complications in Surgery for Chronic Arch Aneurysm:JOURNAL OF CARDIAC SURGERY, Issue 4 2004Axillary Artery Cannulation, Replacement of the Ascending, Selective Cerebral Perfusion, Total Arch Aorta For preventing this complication, axillary artery cannulation, selective cerebral perfusion, and replacement of the ascending and arch aorta were applied to thoracic aortic aneurysm involving aortic arch. Method: From May 1999 to July 2002, consecutive 39 patients with true aneurysm (29 patients) or chronic aortic dissection (10 patients) involving aortic arch underwent replacement of the ascending and arch aorta with an elephant trunk under hypothermic cardiopulmonary bypass through the axillary artery cannulation and selective cerebral perfusion. The brain was continuously perfused without any intermission through the axillary artery. Concomitant operation included coronary artery bypass grafting (CABG) in two patients, aortic valve replacement (AVR) in one, Bentall operation in two, mitral valve replacement (MVR) in one, and aortic valve sparing operation in one. Patient age at operation was 40,84 (72 + 9) years and 24 of them were older than 70 years of age. Results: There was one operative death (2.5%) due to bleeding from the left lung, and one hospital death due to respiratory failure. Postoperative permanent neurological dysfunction was found in one patient (2.5%). Two patients presented temporary neurological dysfunction (5%). Thirty-six of the 39 patients were discharged from hospital on foot. Conclusion: Continuous perfusion through the axillary artery with selective cerebral perfusion and replacement of the ascending and arch aorta may minimize cerebral complication leading to satisfactory results in patients with chronic aortic aneurysm involving aortic arch. [source] Contemporary Results of Total Aortic Arch ReplacementJOURNAL OF CARDIAC SURGERY, Issue 3 2004Thoralf M. Sundt M.D. The results of surgical intervention reported from large centers are improving; however, the degree to which these results are reproducible by other surgeons is less clear. We therefore reviewed our recent experience with total aortic arch replacement. Methods: Between July 1, 1997 and July 1, 2001 19 patients underwent complete aortic arch replacement, with or without concomitant procedures. We retrospectively reviewed perioperative results retrieved from the computerized database and clinical records. Results: The mean age of the study population was 68 ± 8.3 years (range 52 to 82), with women predominating (11 women, 8 men). All patients had hypertension. Patient history indicated active or past tobacco abuse in 16 patients (80%); cerebrovascular disease in 3, and peripheral vascular disease in 7 patients. Associated procedures included an elephant trunk in 12 (63%), replacement of the upper descending thoracic aorta in 5 (26%), concomitant coronary artery bypass in 5 (26%), and aortic root replacement in 3 (16%). One patient underwent replacement of the entire aorta from sinotubular ridge to iliac bifurcation in a single procedure. Brachiocephalic reconstruction with a "Y-graft" permitting early antegrade cerebral perfusion was performed in 12 patients. Retrograde cerebral perfusion was performed in ten patients (53%). Perioperatively, death occurred in two patients (11%) and stroke in two (11%). Conclusions: With cautious application, techniques developed in high-volume centers can also achieve satisfactory results when used at centers with a more modest case volume. (J Card Surg 2004;19:235-239) [source] Management of blood pressure after acute ischemic stroke: An evidence-based guide for the hospitalistJOURNAL OF HOSPITAL MEDICINE, Issue 4 2007Ethan Cumbler MD Abstract Hospitalists are frequently called upon to manage blood pressure after acute ischemic stroke. A review of both post infarction cerebral perfusion physiology and the data from randomized trials of antihypertensive therapy is necessary to explain why consensus guidelines for blood pressure management after stroke differ from those of other hypertensive emergencies. The peri-infarct penumbra is the central concept in understanding post ischemic cerebral perfusion. This area of impaired cerebral blood flow is dependent on mean arterial blood pressure and acute reduction of blood pressure may expand the area of infarction. Review of clinical trials fails to show benefit from reduction of blood pressure after ischemic stroke and current guidelines suggest antihypertensive therapy be employed if the systemic blood pressure is greater than 180/105 mmHg after tPA is employed, or 220/120 mmHg when tPA is not used. Induced hypertension remains a promising but unproven therapy in the acute setting, but the evidence for long term control of blood pressure to less than 140/80 mmHG for secondary prevention of stroke is strong. Adherence to guidelines is poor but it is recognized that current evidence is limited by a lack of trials in which blood pressure is titrated to a pre-specified goal, as is common in clinical practice. Journal of Hospital Medicine 2007;2:261,267. © 2007 Society of Hospital Medicine. [source] Method for improving the accuracy of quantitative cerebral perfusion imaging,JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2005Ken E. Sakaie PhD Abstract Purpose To improve the accuracy of dynamic susceptibility contrast (DSC) measurements of cerebral blood flow (CBF) and volume (CBV). Materials and Methods In eight volunteers, steady-state CBV (CBVSS) was measured using TrueFISP readout of inversion recovery (IR) before and after injection of a bolus of contrast. A standard DSC (STD) perfusion measurement was performed by echo-planar imaging (EPI) during passage of the bolus and subsequently used to calculate the CBF (CBFDSC) and CBV (CBVDSC). The ratio of CBVSS to CBVDSC was used to calibrate measurements of CBV and CBF on a subject-by-subject basis. Results Agreement of values of CBV (1.77 ± 0.27 mL/100 g in white matter (WM), 3.65 ± 1.04 mL/100 g in gray matter (GM)), and CBF (23.6 ± 2.4 mL/(100 g min) in WM, 57.3 ± 18.2 mL/(100 g min) in GM) with published gold-standard values shows improvement after calibration. An F-test comparison of the coefficients of variation of the CBV and CBF showed a significant reduction, with calibration, of the variability of CBV in WM (P< 0.001) and GM (P < 0.03), and of CBF in WM (P < 0.0001). Conclusion The addition of a CBVSS measurement to an STD measurement of cerebral perfusion improves the accuracy of CBV and CBF measurements. The method may prove useful for assessing patients suffering from acute stroke. J. Magn. Reson. Imaging 2005;21:512,519. © 2005 Wiley-Liss, Inc. [source] Time evolution of cerebral perfusion and apparent diffusion coefficient measured by magnetic resonance imaging in a porcine stroke modelJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2002Lisbeth Røhl MD Abstract Purpose To demonstrate the feasibility of sequential diffusion-weighted (DW) and perfusion-weighted (PW) magnetic resonance imaging (MRI) of a recently developed porcine stroke model and to evaluate the evolution of cerebral perfusion and the apparent diffusion coefficient (ADC) over time. Materials and Methods In five pigs, DW imaging (DWI) and PW imaging (PWI) was carried out for 7 hours after stroke onset, starting 1 hour after middle cerebral artery occlusion (MCAO). Results The DWI lesion volume increased significantly with time, and final DWI lesion volume correlated well with lesion area on histological sections (r = 0.910). T2 changes could be recognized 3 hours after stroke onset. At 1 hour the ADC ratio (ischemic lesion/contralateral side) was reduced to 0.81 in the caudate-putamen and to 0.87 in the cortex, and the cerebral blood flow ratio was reduced to 0.40 in the caudate-putamen and 0.51 in the cortex. Conclusion The level of flow reduction in the caudate-putamen and the cortex after 1 hour is in good correlation with human thresholds of irreversible and reversible ischemic damage, and accordingly, this model might be a model for mechanisms of infarct evolution and therapeutic intervention. J. Magn. Reson. Imaging 2002;15:123,129. © 2002 Wiley-Liss, Inc. [source] The mitochondrial uncoupler 2,4-dinitrophenol attenuates tissue damage and improves mitochondrial homeostasis following transient focal cerebral ischemiaJOURNAL OF NEUROCHEMISTRY, Issue 6 2005Amit S. Korde Abstract Ischemic stroke is caused by acute neuronal degeneration provoked by interruption of cerebral blood flow. Although the mechanisms contributing to ischemic neuronal degeneration are myriad, mitochondrial dysfunction is now recognized as a pivotal event that can lead to either necrotic or apoptotic neuronal death. Lack of suitable ,upstream' targets to prevent loss of mitochondrial homeostasis has, so far, restricted the development of mechanistically based interventions to promote neuronal survival. Here, we show that the uncoupling agent 2,4 dinitrophenol (DNP) reduces infarct volume approximately 40% in a model of focal ischemia,reperfusion injury in the rat brain. The mechanism of protection involves an early decrease in mitochondrial reactive oxygen species formation and calcium uptake leading to improved mitochondrial function and a reduction in the release of cytochrome c into the cytoplasm. The observed effects of DNP were not associated with enhanced cerebral perfusion. These findings indicate that compounds with uncoupling properties may confer neuroprotection through a mechanism involving stabilization of mitochondrial function. [source] Bilateral Internal Carotid Artery Dissection Mimicking Inflammatory Demyelinating DiseaseJOURNAL OF NEUROIMAGING, Issue 4 2003C. Lie MD ABSTRACT Background and Purpose. Internal carotid artery (ICA) dissection (ICAD) may be extremely difficult to diagnose only on the basis of historical information and clinical signs, and even standard brain imaging (computed tomography [CT], T2-weighted magnetic resonance imaging [MRI]) may not be sufficient to delineate the underlying pathology clearly, as shown in this case. Methods. The clinical presentation and parenchymal lesion pattern on CT were suggestive of inflammatory demyelinating disease, and additional multiparametric MRI was per-formed. Results. Diffusion-weighted MRI, magnetic resonance angiography, and perfusion-weighted MRI revealed acute ischemic lesions, bilateral ICA obstruction, and bilateral hypoperfusion in the middle cerebral artery territories. Bilateral ICAD was confirmed by Doppler and duplex ultrasound, and anticoagulation therapy was initiated. A follow-up examination showed recanalization of the obstructed ICAs and the normalization of cerebral perfusion. Conclusion. This case illustrates the importance of demonstrating the pathology and the value of multiparametric MRI techniques for the diagnosis and monitoring of ICAD and its hemodynamic consequences. [source] Harmonic Imaging in Acute Stroke: Detection of a Cerebral Perfusion Deficit With Ultrasound and Perfusion MRIJOURNAL OF NEUROIMAGING, Issue 2 2003Karsten Meyer MD ABSTRACT Perfusion harmonic imaging of the brain is a new ultrasound technique for assessing cerebral perfusion. In a patient with acute middle cerebral artery infarction, this method detected a cerebral perfusion deficit corresponding to the area of delayed perfusion as displayed by perfusion magnetic resonance imaging. [source] Cerebral Hemodynamics Changes During Retrograde Brain Perfusion in DogsJOURNAL OF NEUROIMAGING, Issue 2 2001Alexander Y. Razumovsky PhD ABSTRACT The objective of this study was to examine cerebral hemodynamics changes during hypothermic circulatory arrest (HCA) with and without retrograde cerebral perfusion (RCP). Thirteen colony-bred hound dogs were placed on cardiopulmonary bypass (CPB) and cooled to 18°C. Five dogs underwent 2 hours of HCA without RCP and 8 with RCP. The animals were then rewarmed on CPB until normothermic and weaned. Cerebral blood flow velocity (CBFV) and Gosling Pulsatility Index (PI) in the middle cerebral artery (MCA) were studied using transcranial Doppler (TCD) ultrasound. At baseline and during pre- and postarrest CPB, there was anterograde direction of blood flow in the MCA. During HCA with RCP, there was retrograde direction of blood flow in the MCA. There was no difference in CBFV between pre-, during, and postarrest CPB in the group with RCP; however, there was significantly increased CBFV during postarrest CPB in the group without RCP compared to the dogs with RCP. Later, at 3 hours after postarrest CPB, there was decreased CBFV in all animals accompanied by increased PI (2.4 ± 0.4 and 2.2 ± 0.6 for animals with RCP and without RCP, respectively) and abnormal TCD waveform changes including decreased diastolic compartment and sharp systolic peak. During hypothermic circulatory arrest, RCP provides CBFV in the MCA comparable to MCA CBFV during CPB. HCA dogs without RCP showed immediate hyperemia on reperfusion. The decreased CBFV and increased PI at 1 hour after postarrest CPB could be an indicator of progressive ischemic injury due to the increased intracranial pressure despite the implementation of RCP. [source] The Impact of Chronic Cigarette Smoking on Recovery From Cortical Gray Matter Perfusion Deficits in Alcohol Dependence: Longitudinal Arterial Spin Labeling MRIALCOHOLISM, Issue 8 2009Anderson Mon Background:, Neuroimaging studies reported cerebral perfusion abnormalities in individuals with alcohol use disorders. However, no longitudinal magnetic resonance imaging (MRI) studies of cerebral perfusion changes during abstinence from alcohol have been reported. Methods:, Arterial spin labeling MRI was used to evaluate cortical gray matter perfusion changes in short-term abstinent alcohol dependent individuals in treatment and to assess the impact of chronic cigarette smoking on perfusion changes during abstinence. Seventy-six patients were scanned at least once. Data from 19 non-smoking (17 males, 2 females) and 22 smoking (21 males, 1 female) patients scanned at 1 and 5 weeks of abstinence were used to assess perfusion changes over time. Twenty-eight age-equated healthy controls (25 males, 3 females) were scanned for cross-sectional comparison, 13 of them were scanned twice. Given the age range of the cohort (28 to 68 years), age was used as a covariate in the analyses. Mean perfusion was measured in voxels of at least 80% gray matter in the frontal and parietal lobes and related to neurocognitive and substance use measures. Results:, At 1 week of abstinence, frontal and parietal gray matter perfusion in smoking alcoholics was not significantly different from that in non-smoking alcoholics, but each group's perfusion values were significantly lower than in controls. After 5 weeks of abstinence, perfusion of frontal and parietal gray matter in non-smoking alcoholics was significantly higher than that at baseline. However, in smoking alcoholics, perfusion was not significantly different between the time-points in either region. The total number of cigarettes smoked per day was negatively correlated with frontal gray matter perfusion measured at 5 weeks of abstinence. Lobar perfusion measures did not correlate significantly with drinking severity or cognitive domain measures at either time-point. Conclusion:, Although cerebral perfusion in alcohol dependent individuals shows improvement with abstinence from alcohol, cigarette smoking appears to hinder perfusion improvement. [source] Cerebral blood flow velocity increases during a single treatment with the molecular adsorbents recirculating system in patients with acute on chronic liver failureLIVER TRANSPLANTATION, Issue 8 2001Lars E. Schmidt The aim of this uncontrolled pilot study is to determine the effect of treatment with the molecular adsorbents recirculating system (MARS) on cerebral perfusion in patients with acute on chronic liver failure (AOCLF). In 8 patients (median age, 44 years; range, 35 to 52 years) admitted with AOCLF, a single 10-hour MARS treatment was performed. Hepatic encephalopathy (HE) was graded according to the Fogarty criteria. Changes in cerebral perfusion were determined by transcranial Doppler as mean flow velocity (Vmean) in the middle cerebral artery. Arterial ammonia and bilirubin levels were monitored as a measure of the capability of the MARS to remove water-soluble and protein-bound toxins. During MARS treatment, HE grade improved in 3 patients and remained unchanged in 5 patients (P = .11). Vmean increased from 42 cm/sec (range, 26 to 59 cm/sec) to 72 cm/sec (range, 52 to 106 cm/sec; P < .05), whereas arterial ammonia level decreased from 88 ,mol/L (range, 45 to 117 ,mol/L) to 71 ,mol/L (range, 26 to 98 ,mol/L; P < .05) and bilirubin level from 537 ,mol/L (range, 324 to 877 ,mol/L) to 351 ,mol/L (range, 228 to 512 ,mol/L; P < .05). In conclusion, cerebral perfusion is increased and levels of ammonia and bilirubin are reduced during MARS treatment in patients with AOCLF. [source] Regional cerebral blood flow autoregulation in patients with fulminant hepatic failureLIVER TRANSPLANTATION, Issue 6 2000Fin Stolze Larsen The absence of cerebral blood flow autoregulation in patients with fulminant hepatic failure (FHF) implies that changes in arterial pressure directly influence cerebral perfusion. It is assumed that dilatation of cerebral arterioles is responsible for the impaired autoregulation. Recently, frontal blood flow was reported to be lower compared with other brain regions, indicating greater arteriolar tone and perhaps preserved regional cerebral autoregulation. In patients with severe FHF (6 women, 1 man; median age, 46 years; range, 18 to 55 years), we tested the hypothesis that perfusion in the anterior cerebral artery would be less affected by an increase in mean arterial pressure compared with the brain area supplied by the middle cerebral artery. Relative changes in cerebral perfusion were determined by transcranial Doppler,measured mean flow velocity (Vmean), and resistance was determined by pulsatility index in the anterior and middle cerebral arteries. Cerebral autoregulation was evaluated by concomitant measurements of mean arterial pressure and Vmean in the anterior and middle cerebral arteries during norepinephrine infusion. Baseline Vmean was lower in the brain area supplied by the anterior cerebral artery compared with the middle cerebral artery (median, 47 cm/s; range, 21 to 62 cm/s v 70 cm/s; range 43 to 119 cm/s, respectively; P < .05). Also, vascular resistance determined by pulsatility index was greater in the anterior than middle cerebral artery (median, 1.02; range 1.00 to 1.37 v 0.87; range 0.75 to 1.48; P < .01). When arterial pressure was increased from 84 mm Hg (range 57 to 95 mm Hg) to 115 mm Hg (range, 73 to 130 mm Hg) during norepinephrine infusion, Vmean remained unchanged in 2 patients in the anterior cerebral artery, whereas it increased in the middle cerebral artery in all 7 patients. In the remaining patients, Vmean increased approximately 25% in both the anterior and middle cerebral arteries. Thus, this study could only partially confirm the hypothesis that autoregulation is preserved in the brain regions supplied by the anterior cerebral artery in patients with FHF. Although the findings of this small study need to be further evaluated, one should consider that autoregulation may be impaired not only in the brain region supplied by the middle cerebral artery, but also in the area corresponding to the anterior cerebral artery. [source] Reduction of errors in ASL cerebral perfusion and arterial transit time maps using image de-noisingMAGNETIC RESONANCE IN MEDICINE, Issue 3 2010Jack A. Wells Abstract In this work, the performance of image de-noising techniques for reducing errors in arterial spin labeling cerebral blood flow and arterial transit time estimates is investigated. Simulations were used to show that the established arterial spin labeling cerebral blood flow quantification method exhibits the bias behavior common to nonlinear model estimates, and as a result, the reduction of random errors using image de-noising can improve accuracy. To assess the effect on precision, multiple arterial spin labeling data sets acquired from the rat brain were processed using a variety of common de-noising methods (Wiener filter, anisotropic diffusion filter, gaussian filter, wavelet decomposition, and independent component analyses). The various de-noising schemes were also applied to human arterial spin labeling data to assess the possible extent of structure degradation due to excessive spatial smoothing. The animal experiments and simulated data show that noise reduction methods can suppress both random and systematic errors, improving both the precision and accuracy of cerebral blood flow measurements and the precision of transit time maps. A number of these methods (and particularly independent component analysis) were shown to achieve this aim without compromising image contrast. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc. [source] In-vivo visualization of phagocytotic cells in rat brains after transient ischemia by USPIONMR IN BIOMEDICINE, Issue 4 2002M. Rausch Abstract Cerebral ischemia provokes tissue damage by two major patho-physiological mechanisms. Direct cell necrosis is induced by diminished access of neurons and glia to essential nutrients such as glucose and oxygen leading to energy failure. A second factor of cellular loss is related to the activation of immune-competent cells within and around the primary infarct. While granulocytes and presumably monocytes are linked to the no-reflow phenomenon, activated microglia cells and monocytes can release cytotoxic substrates, which cause delayed cell death. As a consequence the infarct volume will increase, despite restoration of cerebral perfusion. In the past, visualization of immune competent cells was only possible by histological analysis of post-mortem tissue. However, contrast agents based on small particles of iron oxide are known to accumulate in organs rich in cells with phagocytotic function. These particles can be tracked in vivo by MRI methods based on their relaxation properties. In the present study, the spatio-temporal distribution of USPIO particles was monitored in a rat model of transient cerebral infarction using T1 - and T2 -weighted MRI sequences. USPIO were detected in vessels at 24,h after administration. At later time points specific accumulation of USPIO was observed within the infarcted hemisphere, with maximal signal enhancement on day 2. Their detectability based on T1 -contrast disappeared between day 4 and day 7. Immuno-histochemically (IHC) stains confirmed the presence of macrophages, presumably blood-derived monocytes within areas of T1 signal enhancement. Direct visualization of iron-burdened macrophages by IHC was only possible later than day 3 after occlusion. Copyright © 2002 John Wiley & Sons, Ltd. [source] The Use of Cerebral Oximetry as a Monitor of the Adequacy of Cerebral Perfusion in a Patient Undergoing Shoulder Surgery in the Beach Chair PositionPAIN PRACTICE, Issue 4 2009Gregory W. Fischer MD Abstract Four cases of ischemic injury have been reported in patients undergoing orthopedic surgery in the upright position. We describe the use of cerebral oximetry as a monitor of the adequacy of cerebral perfusion in a 63-year-old woman who underwent arthroscopic rotator cuff surgery in a beach chair under general anesthesia. During positioning, a decrease in blood pressure was accompanied by a decrease in cerebral oxygen saturation (SctO2) and was treated with phenylephrine. When spontaneous ventilation resumed, an increase in end-tidal carbon dioxide was accompanied by an increase in SctO2. Cerebral oximetry may prove useful as a guide monitor and manage nonsupine patients. [source] Cerebral oxygenation monitoring using near infrared spectroscopy during controlled hypotensionPEDIATRIC ANESTHESIA, Issue 6 2005TORIN SHEAR BS Summary Background:, Controlled hypotension (CH) is used to limit intraoperative blood loss and decrease the need for homologous transfusions. Despite the efficacy of the technique, hypotension has the potential to affect cerebral perfusion and oxygen delivery. There are no data providing a direct measurement of cerebral oxygenation during this technique. Methods:, The current study prospectively evaluated cerebral oxygenation during CH using near infrared spectroscopy. Nineteen patients ranging in age from 6 to 18 years were enrolled in the study. CH was provided using a combination of intravenous opioids and sevoflurane supplemented with labetolol as necessary. Results:, There were a total of 268 readings obtained from the cerebral oximeter. The baseline cerebral oximeter reading was 81 ± 8% on the right and 82 ± 7% on the left. During CH (mean arterial pressure of 65,69, 60,64, 55,59, and <54 mmHg), the right cerebral oximeter values were 80 ± 9, 78 ± 8, 78 ± 10, and 84 ± 9%, respectively while the left cerebral oximeter values were 79 ± 7, 80 ± 7, 78 ± 8, and 78 ± 8%, respectively. Of the 268 readings, there were 11 points (4%) at which either the left or right cerebral oximeter was 10,19 less than the baseline value and no points at which the reading was 20 or more from the baseline value. Conclusions:, Our preliminary data with a measurement of cerebral oxygenation demonstrates the safety of CH within the accepted mean blood pressure recommendations of 55,65 mmHg. [source] Arterial spin-labeled perfusion combined with segmentation techniques to evaluate cerebral blood flow in white and gray matter of children with sickle cell anemia,PEDIATRIC BLOOD & CANCER, Issue 1 2009Kathleen J. Helton MD Abstract Background Changes in cerebral perfusion are an important feature of the pathophysiology of sickle cell anemia (SCA); cerebrovascular ischemia occurs frequently and leads to neurocognitive deficits, silent infarcts, and overt stroke. Non-invasive MRI methods to measure cerebral blood flow (CBF) by arterial spin labeling (ASL) afford new opportunities to characterize disease- and therapy-induced changes in cerebral hemodynamics in patients with SCA. Recent studies have documented elevated gray matter (GM) CBF in untreated children with SCA, but no measurements of white matter (WM) CBF have been reported. Procedures Pulsed ASL with automated brain image segmentation-classification techniques were used to determine the CBF in GM, WM, and abnormal white matter (ABWM) of 21 children with SCA, 18 of whom were receiving hydroxyurea therapy. Results GM and WM CBF were highly associated (R2,=,0.76, P,<,0.0001) and the GM to WM CBF ratio was 1.6 (95% confidence interval: 1.43,1.83). Global GM CBF in our treated cohort was 87,±,24 mL/min/100 g, a value lower than previously reported in untreated patients with SCA. CBF was elevated in normal appearing WM (43,±,14 mL/min/100 g) but decreased in ABWM (6,±,12 mL/min/100 g), compared to published normal pediatric controls. Hemispheric asymmetry in CBF was noted in most patients. Conclusions These perfusion measurements suggest that hydroxyurea may normalize GM CBF in children with SCA, but altered perfusion in WM may persist. This novel combined approach for CBF quantification will facilitate prospective studies of cerebral vasculopathy in SCA, particularly regarding the effects of treatments such as hydroxyurea. Pediatr Blood Cancer 2009;52:85,91. © 2008 Wiley-Liss, Inc. [source] Advances in optical imaging of the newborn infant brainPSYCHOPHYSIOLOGY, Issue 4 2003Jeremy C. Hebden Abstract New methods of imaging the oxygenation, hemodynamics, and metabolism of the newborn infant brain are being developed, based on illumination of the head with near-infrared light. Techniques known as optical topography and optical tomography have the potential to provide valuable information about the function of the normal brain, and about a variety of cerebral pathology such as hypoxic-ischemia. Optical methods provide a unique means of monitoring brain oxygenation safely in an intensive care environment without interference with the normal handling of the infant. Studies on infants have focused on the assessment of steady-state regional cerebral perfusion and tissue oxygenation, as well as monitoring hemodynamic changes in response to sensory stimulation. Recent technological and methodological advances in this research field are reviewed, and the likely impact of optical imaging methods on the care of newborn infants is assessed. [source] Perfusion computed tomography in the acute phase of mild head injury: Regional dysfunction and prognostic value,ANNALS OF NEUROLOGY, Issue 6 2009Zwany Metting MD Objective Traumatic brain injury is a major cause of disability and death. Most patients sustain a mild head injury with a subgroup that experiences disabling symptoms interfering with return to work. Brain imaging in the acute phase is not predictive of outcome, as 20% of noncontrast computed tomographic (CT) scans on admission is normal in patients with a suboptimal outcome. The aim of this study was to perform perfusion CT imaging in the acute phase of mild head injury in patients without intracranial abnormalities on the noncontrast CT, to assess whether these patients had cerebral perfusion abnormalities. Furthermore, the relation between perfusion CT parameters and severity of head injury and outcome was evaluated. Methods In patients with mild head injury and normal noncontrast CT, perfusion CT was performed directly after admission. The perfusion data were compared with data of 25 healthy control subjects. Outcome was determined 6 months after injury with the extended Glasgow Coma Outcome Scale score and return to work. Results Seventy-six patients were included. In patients with a decreased Glasgow Coma Scale score, a significant decrease of cerebral blood flow and cerebral blood volume was detected in the frontal and occipital gray matter. In logistic regression analyses, decreased cerebral blood flow and cerebral blood volume in the frontal lobes predicted worse outcome according to the extended Glasgow Coma Outcome Scale score. CT perfusion parameters did not predict return to work. Interpretation In the acute phase of mild head injury, disturbed cerebral perfusion is seen in patients with normal noncontrast CT correlating with severity of injury and outcome. Ann Neurol 2009;66:809,816 [source] | |||||||||||||||||||||||||