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Introducción. El uso del Doppler transcraneal (DTC) en pacientes neurocríticos se reporta cada vez más en las terapias intensivas pediátricas. El objetivo de esta encuesta es conocer los usos y prácticas del DTC en la atención neurocrítica y el proceso de formación del personal que realiza el estudio. Materiales y métodos. Encuesta a profesionales de 23 unidades de terapia intensiva pediátrica de Argentina. Resultados. Porcentaje de respuesta del 86 %. Se utilizó en sospecha de muerte encefálica (n = 20), trauma de cráneo (n = 16) y accidente cerebrovascular (n = 16). El intensivista pediátrico es quien realiza los estudios (n = 13/20). Los encuestados utilizan el Doppler para decidir conductas y tratamientos, comenzar el proceso de evaluación de muerte encefálica, solicitar tomografía de cerebro y manejar la presión de perfusión cerebral con vasopresores. Conclusión. Todos los encuestados utilizan los hallazgos del DTC para guiar tratamientos o conductas. La mitad de los encuestados está poco conforme con la capacitación recibida.
Introduction. The use of transcranial Doppler (TCD) ultrasoundin neurocritical patients is reported to be increasingly common in pediatric intensive care units. The objective of this survey was to know about the use and practice of TCD ultrasound in neurocritical care and the training process of staff members performing it. Materials and methods. Survey administered to providers from 23 pediatric intensive care units of Argentina. Results. The percentage of response was 86%. TCD ultrasound was used for suspected brain death (n = 20), head injury (n = 16), and stroke (n = 16). Pediatric intensivists perform the test (n = 13/20). Surveyed participants use TCD ultrasound to decide on treatment and management, start brain death assessment, request brain computed tomography, and manage cerebral perfusion pressure with vasopressors. Conclusion. All surveyed participants use TCD ultrasound findings to guide management or treatments. Half of surveyed participants are little satisfied with their training.
Subject(s)
Humans , Child, Preschool , Child , Brain Death , Critical Care/methods , Argentina , Intensive Care Units, Pediatric , Ultrasonography, Doppler, Transcranial/methodsABSTRACT
OBJECTIVE: To evaluate the findings of magnetic resonance angiography (MRA) and transcranial Doppler ultrasound (TCD) in patients with a clinical diagnosis of vertebrobasilar insufficiency (VBI). METHOD: From our outpatient neurotology clinic, we selected patients (using the criteria proposed by Grad and Baloh) with a clinical diagnosis of VBI. We excluded patients with any definite cause for vestibular symptoms, a noncontrolled metabolic disease or any contraindication to MRA or TCD. The patients in the study group were sex- and age-matched with subjects who did not have vestibular symptoms (control group). Our final group of patients included 24 patients (study, n=12; control, n=12). RESULTS: The MRA results did not demonstrate significant differences in the findings between our study and control groups. TCD demonstrated that the systolic pulse velocity of the right middle cerebral artery, end diastolic velocity of the basilar artery, pulsatility index (PI) of the left middle cerebral artery, PI of the right middle cerebral artery, and PI of the basilar artery were significantly higher in the study group than in the control group, suggesting abnormalities affecting the microcirculation of patients with a clinical diagnosis of VBI compared with controls. CONCLUSION: MRA failed to reveal abnormalities in patients with a clinical diagnosis of VBI compared with controls. The PI of the basilar artery, measured using TCD, demonstrated high sensitivity (91%) and specificity (91%) for detecting clinically diagnosed VBI.
Subject(s)
Humans , Basilar Artery/diagnostic imaging , Vertebrobasilar Insufficiency/diagnostic imaging , Ultrasonography, Doppler, Transcranial/methods , Magnetic Resonance Angiography , Blood Flow Velocity , MicrocirculationABSTRACT
Introducción: la drepanocitosis es la enfermedad genética más frecuente en el mundo. Las complicaciones neurológicas y sus secuelas se conocen casi desde la primera descripción de la enfermedad. La más frecuente es el accidente vascular encefálico (AVE); especialmente en la primera década de la vida, posiblemente porque la velocidad del flujo circulatorio en las arterias cerebrales es más alta en el niño. El riesgo de tener AVE se puede monitorear mediante técnicas no invasivas como la ecografía doppler transcraneal del segmento supraclinoideo de la arteria carótida interna y cerebral media y, relacionando estos resultados con parámetros clínicos y de laboratorio. Objetivo: caracterizar los factores de riesgo relacionados con el accidente vascular encefálico en niños con drepanocitosis. Métodos: se realizó un estudio descriptivo retrospectivo en 104 pacientes con diagnóstico de drepanocitosis atendidos en el servicio de Pediatría del Instituto de Hematología e Inmunología de La Habana, entre 2003 y 2011. Los enfermos se dividieron en dos grupos: genotipos más sintomáticos (HbSS y la HbSß0) y menos sintomáticos (HbSC y HbSß+). Se estudiaron las alteraciones del flujo sanguíneo cerebral (FSC) por ecografía doppler transcraneal y se relacionaron con elementos clínicos y hematológicos. Resultados: el 48 por ciento de los pacientes tenían edad entre los 3 y 11 años. Prevaleció el grupo más sintomático, en el cual las arterias con mayor velocidad del FSC fueron la arteria cerebral media derecha (115,8 ± 42,5 cm/s) y la izquierda (113,7± 40,8 cm/s). En este grupo prevalecieron significativamente las crisis vasoclusivas dolorosas (136,4± 20; 1,3/100 pacientes/año), los ingresos (90,9±14,3; 0,9/100 pacientes/año), las transfusiones (72,7±16,3; 0,7/100 pacientes/año) y el síndrome torácico agudo (STA) (27,3±8,2; 2,8/100 pacientes/año). Hubo una correlación inversa entre la hemoglobina y la velocidad del FSC; la LDH tuvo significación estadística 1 211,8± 503,9 UI/L, con diferencias significativas entre los grupos; p=0,027(AU)
Introduction: Sickle cell disease is the most common genetic disease in the world. Neurological complications and their sequelae have been known almost since the first disease description. Stroke is the most frequent, especially in the first decade of life, perhaps as consequence of blood flow velocity of cerebral arteries is higher in children. The stroke risk could be monitorized by non-invasive technics such as transcranial Doppler ultrasound (TCD) of cerebral arteries and related with clinical and laboratorial parameters. Objective: To characterize risk factors related to stroke in children with sickle cell disease. Methods: A retrospective descriptive study was conducted in 104 patients diagnosed with sickle cell disease and treated in Pediatric Service of the Institute of Hematology and Immunology (IHI) in Havana from 2003 to 2011. The patients were divided into two groups: more symptomatic genotypes (HBSS and HbSß0); and less symptomatic (HbSC and HbSß +). Alterations of cerebral blood flow (CBF) were obtained TCD and were related to clinical and hematological elements. Results: 48 percent of patients were aged between 3 - 11 years. The most symptomatic group prevailed and the arteries in it showing greater speed FSC were right middle cerebral artery (MCA) (115.8 ± 42,5 cm /s) and left MCA (113.7 ± 40,8 cm /s). Also in this group prevailed significantly: painful vaso-occlusive crises (136.4 ± 20, 1.3 per 100 patients/year), admissions (90.9 ± 14.3, 0.9 per 100 patients/year), transfusions (72.7 ± 16.3, 0.7 per 100 patients/year), and acute chest syndrome (27.3 ± 8.2; 2.8 100 patients/year). There was an inverse correlation between hemoglobin and CBF velocity; and lactate dehydrogenase LDH had statistical significance 1211,8 ± 503.9 IU / L, establishing a significant difference between groups (p = 0.027)(AU)
Subject(s)
Humans , Male , Female , Child , Sickle Cell Trait/complications , Stroke/complications , Epidemiology, Descriptive , Retrospective Studies , Risk FactorsABSTRACT
ABSTRACT Background: The etiology of stroke, a severe complication of sickle cell anemia, involves inflammatory processes. However, the pathogenetic mechanisms are unknown. The aim of this study was to evaluate the influence of interleukin-10 polymorphisms and haplotypes on the risk of acute cerebral ischemia and high-risk transcranial Doppler in 395 children with sickle cell anemia from the state of Minas Gerais, Brazil. Methods: Interleukin-10 haplotypes were determined by polymerase chain reaction-restriction fragment length polymorphism and sequencing. The outcomes studied were acute cerebral ischemia and high-risk transcranial Doppler. Clinical data were retrieved from the children's records. Results: There was no statistically significant difference in the frequencies of polymorphisms and haplotypes between children with and without acute cerebral ischemia or children with or without high-risk transcranial Doppler. These data are consistent with a previous report that showed an absence of association between interleukin-10 plasma levels and high-risk transcranial Doppler velocity in children with sickle cell anemia. Conclusion: Interleukin-10 haplotypes were not associated with the risk of acute cerebral ischemia or high-risk transcranial Doppler velocity in children with sickle cell anemia from the state of Minas Gerais, Brazil.
Subject(s)
Humans , Male , Female , Child , Polymorphism, Genetic , Interleukin-10 , Ultrasonography, Doppler, Transcranial , Stroke , Anemia, Sickle Cell , Brain Ischemia , ChildABSTRACT
Objective To apply color Doppler flow imaging (CDFI) and transcranial Doppler (TCD) to the follow-up observation of the changes of cervical vessel,intracranial hemodynamics and cerebrovascular reserve capacity (CVR) of the patients after carotid artery stent implantation.Methods Totally 96 patients with carotid artery stent implantation underwent CDFI and TCD examinations,and the changes of hemodynamics were compared before and 1 month,6 months,1 a and 2 a after implantation.Results The values of peak systolic velocity (PSV) and resistance index (RI) at the areas of carotid stenosis were lower significantly than those before implantation,while the values of PSV,pulsatility index (PI) and CVR of the middle cerebral artery were obviously higher than those before implantation (P＜0.05).There were no significant differences between the cervical and intracranial hemodynamics indexes 1 month,6 months,1 a and 2 a after treatment.Two-year follow-up found 4 cases of restenoses after implantation,and the rate for restenosis was 4.2％.Conclusion Carotid artery stent implantation improves significantly cervical and intracranial blood supply as well as CVR of the carotid stenosis patient,and CDFI combined with TCD can be used for the accurate evaluation of the efficacy and postoperative follow-up of carotid artery stent implantation.
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Objective:To study the diagnosis value of Transcranial Doppler ultrasound for intracranial artery stenosis in patients with cerebral infarction.Methods:A total of 140 patients with acute cerebral infarction,transient ischemic attack and posterior circulation ischemic attack in Department of Neurology,Xinjiang cardiovascular and cerebrovascular disease hospital from October 2014 to October 2016 were selected as research object,CT angiography (CTA) and TCD detection were performed in all patients.Used CTA examination results as the gold standard,the detection results of intracranial artery stenosis in two groups were compared,the diagnostic value of TCD and the diagnostic results of TCD to the degree of bilateral middle cerebral artery (MCA) stenosis were analyzed.Results:CTA diagnosis showed that 140 patients had a total of 105 patients with intracranial artery stenosis,in the anterior and posterior circulation vessel of 1155 intracranial segments,CTA detection showed that 249 vessels were narrow,TCD detection showed that 236 vessels were narrow.Com-pared with CTA,TCD was better in the diagnosis of patients (Kappa value＞0.75).The diagnostic sensitivity and positive predictive value of TCD for MCA were the highest,which were 91.26％ and 93.07％,the consistency was the best (Kappa value =0.917).CTA detection showed that 210 MCA vessels had 103 stenoses,mild stenosis 17,moderate stenosis 41,severe stenosis 45,TCD detection showed that the stenosis was 101,mild stenosis 16,moderate stenosis 40,severe stenosis 45.The Kappa test showed that the diagnostic results of TCD to the degree ofMCA stenosis was better consistency compared with CTA (Kappa value=0.884.Conclusion:TCD has a high diagnostic value for cerebral artery stenosis in patients with cerebral infarction,and it is consistent with the diagnosis of CTA.
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Introducción: las complicaciones neurológicas y sus secuelas se conocen casi desde la primera descripción de la depranocitosis y son más frecuentes en la anemia drepanocítica. Varían con la edad; pueden ser agudas o crónicas y producen una elevada morbimortalidad. Objetivo: conocer la frecuencia de niños con AD que tienen alteraciones en la velocidad del flujo sanguíneo cerebral, relacionar estas alteraciones con los eventos clínicos y los datos de laboratorio y evaluar la evolución en el tiempo de los pacientes con alteraciones y su asociación con el uso de hidroxiurea. Métodos: se realizó un estudio prospectivo analítico que incluyó a 50 pacientes con anemia drepanocítica con edades comprendidas entre 5 y 18 años, atendidos en el Instituto de Hematología e Inmunología. Se determinaron las alteraciones del flujo sanguíneo cerebral (FSC) y su asociación con otros elementos clínicos y hematológicos. Resultados: las arterias que mayor velocidad del FSC mostraron fueron la arteria cerebral media derecha (121,6 cm/s) y la izquierda (115 cm/s). Las alteraciones de la velocidad del FSC en el ultrasonido doppler transcraneal (UDTC) fueron: 11 (22 por ciento) pacientes con velocidades mayores de 170 cm/s, 6 (12 por ciento) con un flujo entre 170 199 cm/s, y 5 (10 por ciento) mayor de 200 cm/s. Existió una correlación inversa entre la velocidad del FSC con la edad y las cifras de hemoglobina, y directa con la cifra de plaquetas. El accidente vascular encefálico, las transfusiones y las hospitalizaciones fueron los eventos clínicos más frecuentes en los pacientes con UDTC anormal. Las velocidades del FSC disminuyeron significativamente (31 cm/s; p = 0,034) en los pacientes que recibieron tratamiento con hidroxiurea. Conclusiones: la detección de alteraciones en el UDTC permite detectar el riesgo de AVE y adoptar las medidas oportunas de prevención del AVE(AU)
Introduction: neurological complications and their sequelae are known almost since the first description of sickle cell disease, most commonly in sickle cell anemia. They vary with age, can be acute or chronic and produce high morbidity and mortality. Aims: to determine the frequency of children with AD who have alterations in cerebral blood flow velocity, relate these changes to clinical events and laboratory data and assess the evolution over time of patients with abnormalities and their association with the use of hydroxyurea. Methods: a prospective analytical study involving 50 patients with sickle cell disease, aged 5 to 18, was performed in at the Institute of Hematology and Immunology where they are assisted. Alterations in cerebral blood flow (CBF) and the association with other clinical and hematological elements were determined. Results: the arteries that showed larger speed were right middle cerebral artery (121.6 cm/s) and left (115 cm/s). Patients with impaired CBF velocity in transcranial Doppler ultrasound were 11 ( 22 percent) with speeds greater higher than 170 cm/s , 6 patients (12 percent) with a flow between 170-199 cm/s, and five (10 percent) greater higher than 200 cm / s. There was an inverse correlation between CBF velocity with age and hemoglobin levels and directly with the platelet count. The cerebrovascular accident, blood transfusions and hospitalizations were the most frequent clinical events in patients with abnormal transcranial doppler ultrasound. FSC velocities were significantly decreased (31 cm /s; p = 0,034) in patients receiving treatment with hydroxyurea. Conclusions: Patients with alterations in the transcranial Doppler ultrasound must be included in a program for primary prevention of cerebrovascular accident(AU)
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Sickle Cell Trait/complications , Sickle Cell Trait/diagnostic imaging , Ultrasonography, Doppler, Transcranial/methods , Prospective Studies , Stroke/prevention & controlABSTRACT
Objective To probe into the application value of Transcranial Doppler ultrasound (TCD)for hypertension in health examination by retrospective analyzing the characteristics of TCD in Hy-pertension patients.Methods Five hundred and sixty -eight hypertension patients diagnosed in health ex-amination conducted from February 2011 to December 2014 in our hospital were selected as hypertension group,and 500 normal people participated who except hypertension in the health examination during the same period as control group.All the subjects were examined with TCD,and the results of examination in two groups were comparatively analyzed.Results Four hundred and ninety -six cases TCD examination results of 568 patients were abnormal(87.32%)in hypertension group,including 310 cases of cerebral ar-teriosclerosis(54.58%),268 cases of reduced blood flow velocity(47.18%),228 cases of elevated blood flow velocity(40.14%),245 cases of increased pulsatility index(PI)(43.13%),315 cases of increased re-sistance index (RI)(55.46%),and 231 cases of increased systolic velocity/diastolic velocity (S /D) (40.67%).The number of abnormal cases is significantly higher than that of the control group,and the difference has statistical significance (P <0.05).At the same time,compared with the control group,the mean velocity(Vm),systolic velocity(Vs)and diastolic velocity(Vd)of the bilateral middle cerebral artery (MCA)and the basilar artery(BA)in hypertension group are decreased significantly,while the PI,RI and S /D increased significantly,all the difference of which has statistical significance(P <0.05).Conclu-sions TCD can accurately reflect the hemodynamics status,the brain atherosclerosis and other pathologic changes,contributing to the assessment of hypertension and prediction of cerebrovascular diseases.Besides,it provides references for the clinical treatment and has positive effects on the prevention of cerebrovascular diseases.
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Objective To observe the effect of Tongsaimai Tablets on the leptomeningeal collateral circulation established after acute cerebral infarction by TCD.Methods 50 patients with acute cerebral infarction were randomly divided into control group (received conventional treatment) and treatment group (received Tongsainai Tablets three times a day,1.75g each time,on the basis of conventional treatment).The leptomeningeal collateral circulation of the two groups were observed after 6 months.Results The factors which may affect the leptomeningeal collateral circulation,such as age,the prevalence of hypertension and hyperlipidemia,original compensatory status of cerebral artery between the two groups had no statistically significant differences.The open rate of leptomeningeal collateral circulation in the treatment group was 64.00％,which was significantly higher than that of the control group(32.00％)(P =0.024).Conclusion Tongsaimai Tablets can promote the formation of leptomeningeal collateral circulation in patients with acute cerebral infarction.
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Objective To explore the different changes of the adult cerebral blood flow with ages,different weight and gender,to summarize the changing characteristics of cerebral blood flow.Methods 360 cases of examination were divided into two groups according to gender,and were divided into five groups at different ages,and were divided into four groups according to body mass index,using TCD detector blood flow velocity.Results 196 cases of male physical examination,the mean cerebral blood flow was (969.37 ± 117.54)ml/min;the 164 females physical examination,the average cerebral blood flow was (987.76 ± 114.34)ml/min,there was no statistically significant difference (P ＞ 0.05).Different ages cerebral blood flow velocity were different,20 to 29-year-old group and the 30 to 39-year-old group had no significant difference (P ＞ 0.05) ;40 to 49-year-old group,50 to 59 years,60 to 69 years old ＞ 70 age group significantly declined compoued with the first two groups,there was significant difference (P ＜ 0.05) ;there were significant difference between the four groups (P ＜ 0.05).Overweight and obese group were significantly lower than the light and the normal group,there was a statistically significant difference (P ＜ 0.05).Conclusion TCDcan be a sensitive and accurate hemodynamic changes in the human brain,and is very important in the early diagnosis,prevention,treatment,and follow-up of cerebrovascular disease.
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El accidente vascular encefálico (AVE) es una de las complicaciones más graves de la drepanocitosis. Se presenta, sobre todo, en la primera década de la vida, tiene tendencia a recurrir y puede dejar secuelas neurológicas y cognoscitivas permanentes. Su prevención y tratamiento óptimos no se han establecido con precisión, pero en el momento actual, los que más se utilizan con buenos resultados son las transfusiones de glóbulos rojos y la hidroxiurea. El ultrasonido doppler transcraneal (UDTC) es un método útil y no invasivo para predecir el AVE en un número grande de pacientes.
Stroke is one of the more severe complications of drepanocytemia. It appears mainly in the first decade of life, with a trend to recurrence, and with cognitive and neurologic permanents. Its optimal prevention and treatment are not accurately established, but nowadays, the more used strategies with better results are the red-blood cell transfusions and the hydroxyurea. Transcranial Doppler ultrasound (TCUS) is an usefulness and safe method to predict stroke in many patients.
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@#Objective To determine the effect of transcranial Doppler ultrasound (TCD) combined with focal mild hypothermia on cerebral infarction treated with thrombolytic unokinase (UK).Methods32 rabbits were randomly divided into the TCD group, UK group, TCD+UK group and hypothermia group with 8 animals in each group. Mean velocities of the middle cerebral artery were recorded after unokinase infusion to estimate whether blood vessels reopened. Meantime, brain temperature of lesion site was tested to find out whether declined to hypothermia level.ResultsThe percentage of recanalization was 87.5% in the hypothermia group, 75% in the TCD+UK group, significantly higher than that in the UK group (37.5%)(P<0.05). After 30 minutes of the rabbit refrigerated at 2 ℃, the putamen temperature declined to 32 ℃～34 ℃.ConclusionApply the regional refrigerstor apparatus to decline the brain temperature to mild hypothermia level during therapeutic time window. TCD combined with focal mild hypothermia can improve the thrombolytic effect of unokinase.
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Objective To evaluate whether the number of high intensity transient signals(HITS)intraoperative detected by transcranial doppler ultrasound(TCD)can predict postoperative neuropsychological deficit.Methods Twenty patients scheduled for coronary artery bypass grafting(CABG)operation with cardiopulmonary bypass were enrolled in this study.HITS were recorded by TCD intraoperatively.And neuropsychological test battery was used to assess postoperative neuropsychological changes.Results There was no significant difference in the number of HITS compared with patients with or without neuropsychological changes.And multivariable correlation between the test scores and the number of HITS showed there was a weak correlation between RW Dgt-Dg5 and HITS(P＜0.05).Conclusion The number of HITS detected during cardiopulmonary bypass(CPB) do not!correlate with the postoperative neuropsychologial changes.
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Transcranial Doppler (TCD) was carried out to determine the resistive index (RI) values of normal canine cerebral arteries and its reproducibility and to evaluate the change of cerebral vascular resistance following diuretics administration. RI values of rostral cerebral artery (RCA) were compared between fontanelle window and temporal window. Normal ranges and reproducibility of the RI values were examined in the rostal cerebral artery (RCA) and caudal cerebral artery (CCA). And after administration of diuretics, TCD-derived RI values were measured at RCA and CCA. Cerebral vascular RI values of RCA and CCA were 0.55 +/- 0.05 and 0.55 +/- 0.03 in the normal dogs, respectively. There was no significant difference of RI between male and female; between fontanelle window and temporal window. Reproducibility of RI measurements between intraobserver and interobserver were relatively high. The RI of RCA and CCA were significantly increased 15 minutes after mannitol administration (p<0.01) and returned to baseline values by 30 minutes, but it did not significantly change after furosemide and saline administration. The results suggest that TCD is a useful test which can obtain reproducible results from any window and has the advantage of detecting subtle changes in cerebral vascular resistance.
Subject(s)
Animals , Cerebral Arteries/drug effects , Diuretics/pharmacology , Dogs/physiology , Feasibility Studies , Furosemide/pharmacology , Mannitol/pharmacology , Reference Values , Reproducibility of Results , Ultrasonography, Doppler/veterinary , Vascular Resistance/drug effectsABSTRACT
Objective To study the therapeutic effects of intermittent hypoxia therapy(IHT)in isolated systolic hypertension(ISH)patients with elevated cerebral blood flow velocity(Vp),and to explore the mechanisms involved.Methods Seventy-six ISH patients with increasing Vp and normal pulsatility index(PI)of the middle ce- rebral artery(MCA)were randomly divided into a therapy group and a control group.IHT was administrated in the therapy group,and air in the control group.The Vp and PI of the MCA and blood pressure(BP)were observed be- fore and after treatment.Results Vp and systolic blood pressure(SBP)were significantly reduced after IHT(P＜0.01)compared with the therapy group's scores betore treatment,but PI and diastolic blood pressure showed no sig- nificant difference.There was no significant change in BP,Vp or PI in the control group before or after treatment. Conclusion IHT has therapeutic effects on ISH by reducing Vp and moderating SBP.
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Objective To get more diagnostic informa ti on from the acute cerebral infarct, We used1HMRS and TCD to investigate the r elationship between the metabolites in the infarct, the infarct volume, blood f low velocity and blood flow to the infarct, and the clinical neurologic deficit. MethodsFifteen patients with acute cerebral infarct underwent1HMRS and TCD examinations. Clinical neurologic deficit score was c ollected from every patient record at the time of the1HMRS and TCD study. Inf arct volume (V/ml) was determined with machine software automatically. A PRESS a cquisition was used for1HMRS. The peak areas of N,Lac,Cr,Cho in the lesi on region were compared with those in the contralateral side. TCD was performed for measuring Vs, Vm of encephalic blood vessels on both sides, and the responsi ble cerebral blood flow was estimated by Vs. ResultsT here were significant decrease of N,Cr,Vm and ECBF in the lesion region when c ompared with the contralateral side( P
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We present the examination technique and normal values of flow velocity from intracranial basal cerebral arteries for a recently developed pulsed Doppler system operating at 2 MHz emitting frequency. Peak systolic, peak diastolic, and mean flow velocity values are analyzed from fast-Fourier transformed(FFT) Doppler spectra at selected depths for 50 presumed normal subjects ranging in age from 18 to 72 years. Interindividual variation is high for peak flow but moderate for mean flow velocity values, which hence are more likely to discriminate normal from abnormal. Flow velocity values within the posterior cerebral attery(PCA) and the basilar artery(BA) are significantly lower than in the anterior cerebral artery(ACA) and the middle cerebral artery(MCA), which is also unique in showing significantly decreasing values with increasing age. Calculated mean flow velocities are 61+/-14 cm/s in the middle cerebral artery(MCA) and 51+/-14 cm/s in the anterior cerebral artery(ACA), and 45+/-11 cm/s in the posterior cerebral artery(PCA) through the temporal window and 43+/-14 cm/s in the basilar artery through the suboccipital window and 15+/-5 cm/s in the ophthalmic artery and 47+/-13 cm/s in the internal carotid artery(lCA) through the transorbital window. A new scanning system is introduced, which we suggest will reduce interindividual variations and improve the accurate separation of nearby vessels, which are major causes of the comparatively large standard deviations at present.