Signal Conversion and Isolation Processing Technology Used in the Cerebrovascular Stroke Detector / 中国医疗器械杂志

By using Doppler sensor and pressure sensor, the cerebrovascular stroke detector can be used to measure the blood flow velocity and blood pressure of the carotid artery. In this study, a variety of signal conversion and isolation processing techniques are proposed for processing and feature extraction of the output signals from the sensors. Finally, effective signal output waveforms that can be used to evaluate the cerebrovascular hemodynamics index (CVHI) are obtained, and the sound signal outputs that can reflect the change characteristics of blood flow velocity and blood pressure signals are generated, which realizes the application functional requirements of the detector.

Cirugía de hombro en posición silla de playa: estrategias y recomendaciones para la prevención de complicaciones isquémicas / Strategies and recommendations for the prevention of ischemic complications in beach chair position for shoulder surgery

Beach chair position is require for Shoulder surgery frequently for proper resolution. The stroke associated with shoulder surgery is a rare complication and probably underreported. The objective of this article is to review the pathophysiology of the ischemic damage associated with beach chair position, learn about strategies and develop recommendations to minimize risks.

La cirugía de hombro (CH), requiere y requerirá colocar a los pacientes en la posición en silla de playa (PSP), cada vez con mayor frecuencia para su adecuada resolución. El asociado a CH, es una complicación poco frecuente y probablmente subreportada. El objetivo de esta revisión, es repasar la fisiopatología del daño isquémico asociado a PSP, conocer estrategias y elaborar recomedaciones destinadas a minimizar riesgos.

Analyzing the neuropsychological characteristics and changes in serum markers of patients with chronic cerebral circulation insufficiency

Summary Objective: To investigate the neuropsychological characteristics and changes in CRP, S100B, MBP, HSP-7, and NSE in serum. Method: Sixty-six (66) patients treated in our hospital as CCCI group were chosen for our study, and 90 patients with depression were selected as the depression group. The patients in both groups were examined with CT perfusion, depression, anxiety and cognition evaluation. Their serum CRP, S100B, MBP, HSP-70 and NSE levels were detected. Neuropsychological and serum markers characteristics were compared. Results: The CBF and CBV in bilateral basal ganglia, frontal lobes, greater oval center, brain stem, and left and right regions of occipital lobes of the patients in CCCI group were significantly lower than in the depression group. The HAMD and HAMA scores of CCCI group patients were significantly lower than in the depression group; CCCI group performed better regarding attention, memory, abstract terms and delayed recall. CCCI also had significantly higher total scores than the depression group. Serum CRP, S100B, MBP, HSP-70 and NSE levels in CCCI group were significantly higher than in the depression group. The differences reach statistical significance (p<0.05). Conclusion: CCCI patients who are accompanied by minor depressive disorder have different degrees of cognitive impairment and experience a significant rise in serum CRP, S100B, MBP, HSP-70 and NSE.

Cerebral hemodynamic and metabolic changes in fulminant hepatic failure / Modificações da hemodinâmica e metabolismo cerebral na insuficiência hepatica fulminante

ABSTRACT Intracranial hypertension and brain swelling are a major cause of morbidity and mortality of patients suffering from fulminant hepatic failure (FHF). The pathogenesis of these complications has been investigated in man, in experimental models and in isolated cell systems. Currently, the mechanism underlying cerebral edema and intracranial hypertension in the presence of FHF is multi-factorial in etiology and only partially understood. The aim of this paper is to review the pathophysiology of cerebral hemodynamic and metabolism changes in FHF in order to improve understanding of intracranial dynamics complication in FHF.

RESUMO O edema cerebral e a hipertensão intracraniana (HIC) são as principais causas de morbidade e mortalidade de pacientes com insuficiência hepática fulminante (IHF). A patogênese dessas complicações tem sido investigada no homem, em modelos experimentais e em sistemas celulares isolados. Atualmente, o mecanismo subjacente ao edema cerebral e HIC na presença de IHF é multifatorial em etiologia e pouco compreendido na literatura. O objetivo deste trabalho é revisar a fisiopatologia das alterações hemodinâmicas e metabólicas cerebrais na IHF, visando melhorar a compreensão da complicação da hemodinâmica encefálica na IHF.

Patients with sickle cell disease are frequently excluded from the benefits of transcranial doppler screening for the risk of stroke despite extensive and compelling evidence / Pacientes com doença falciforme são frequentemente excluídos dos benefícios do screening com doppler transcraniano para avaliação do risco de acidente vascular cerebral, apesar de evidência extensa e convincente

ABSTRACT Transcranial doppler (TCD) is a strategic component of primary stroke prevention in children with sickle cell disease (SCD). This study was conducted to examine the TCD characteristics of children with SCD in nine different medical centers in Brazil. Methods: Transcranial doppler was performed in accordance with the Stroke Prevention Trial in Sickle Cell Anemia Protocol. Results: Of the 396 patients, 69.5% had homozygous SS hemoglobin. The TCD result was abnormal in 4.8%, conditional in 12.6%, inadequate in 4.3% and abnormally low in 1% of patients. The highest mean flow velocities were 121±23.83cm/s and 124±27.21cm/s in the left and right middle cerebral artery respectively. A total of 28.8% patients (mean age 9.19±5.92 years) were evaluated with TCD for the first time. Conclusions: The SCD patients were evaluated with TCD at an older age, representing an important missed opportunity for stroke prevention. Since TCD screening in patients with SCD is important to detect those at high risk for stroke, it is recommended that this screening should be made more readily available.

RESUMO Doppler transcraniano (DTC) é um componente estratégico da prevenção primária do acidente vascular cerebral (AVC) em crianças com doença falciforme (DF). Este estudo foi realizado para examinar as características do DTC de crianças com DF em nove centros médicos diferentes no Brasil. Métodos: DTC foi realizado de acordo com o protocolo de Stroke Prevention Trial in Sickle Cell Anemia Protocol (STOP). Resultados: Dos 396 pacientes avaliados, 69,5% eram homozigotos para hemoglobina SS. DTC foi anormal em 4,8%, condicional em 12,6%, inadequado em 5,3% e anormalmente baixo em 1%. As máximas velocidades de fluxo médio foram 121 ± 23,83cm/s e 124 ± 27,21 cm/s nas artérias cerebrais media esquerda e direita, respectivamente. Um total de 28,8% dos pacientes (média de 9,19 ± 5,92 anos) foram avaliados com o DTC pela primeira vez. Conclusões: Pacientes com DF foram avaliados com DTC numa idade considerada avançada, o que representa uma importante oportunidade perdida para a prevenção de AVC nessa população. Uma vez que a triagem com DTC em pacientes com DF é essencial para detectar aqueles com alto risco de AVC, recomenda-se que essa triagem seja amplamente disponível no país.

Cerebral blood flow and vasoreactivity in aging: an arterial spin labeling study

Regional cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in young and elderly participants were assessed using pulsed arterial spin labeling (ASL) and blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) techniques in combination with inhalation of CO2. Pulsed ASL and BOLD-MRI were acquired in seventeen asymptomatic volunteers (10 young adults, age: 30±7 years; 7 elderly adults, age: 64±8 years) with no history of diabetes, hypertension, and neurological diseases. Data from one elderly participant was excluded due to the incorrigible head motion. Average baseline CBF in gray matter was significantly reduced in elderly (46±9 mL·100 g-1·min-1) compared to young adults (57±8 mL·100 g-1·min-1; P=0.02). Decreased pulsed ASL-CVR and BOLD-CVR in gray matter were also observed in elderly (2.12±1.30 and 0.13±0.06 %/mmHg, respectively) compared to young adults (3.28±1.43 and 0.28±0.11 %/mmHg, respectively; P<0.05), suggesting some degree of vascular impairment with aging. Moreover, age-related decrease in baseline CBF was observed in different brain regions (inferior, middle and superior frontal gyri; precentral and postcentral gyri; superior temporal gyrus; cingulate gyri; insula, putamen, caudate, and supramarginal gyrus). In conclusion, CBF and CVR were successfully investigated using a protocol that causes minimal or no discomfort for the participants. Age-related decreases in baseline CBF and CVR were observed in the cerebral cortex, which may be related to the vulnerability for neurological disorders in aging.

Collateral blood vessels in acute ischemic stroke: a physiological window to predict future outcomes / Circulação colateral no acidente vascular cerebral isquêmico: uma janela fisiológica para prever resultados futuros

ABSTRACT Collateral circulation is a physiologic pathway that protects the brain against ischemic injury and can potentially bypass the effect of a blocked artery, thereby influencing ischemic lesion size and growth. Several recent stroke trials have provided information about the role of collaterals in stroke pathophysiology, and collateral perfusion has been recognized to influence arterial recanalization, reperfusion, hemorrhagic transformation, and neurological outcomes after stroke. Our current aim is to summarize the anatomy and physiology of the collateral circulation and to present and discuss a comprehensible review of the related knowledge, particularly the effects of collateral circulation on the time course of ischemic injury and stroke severity, as well as imaging findings and therapeutic implications.

RESUMO A circulação colateral é um circuito fisiológico de proteção contra alterações isquêmicas que, potencialmente, evita os efeitos de uma oclusão arterial e com isso pode influenciar nas dimensões e no crescimento de uma lesão isquêmica. Vários estudos recentes forneceram informações a respeito do papel das colaterais na fisiopatologia do acidente vascular encefálico isquêmico e demonstraram a capacidade da circulação colateral de influenciar as taxas de reperfusão, recanalização, transformação hemorrágica e com isso desfecho clínico dos pacientes. O objetivo desta revisão é sintetizar a anatomia e a fisiologia da circulação colateral encefálica, apresentando e discutindo, o que se conhece atualmente acerca do seu efeito na cronologia e gravidade da lesão isquêmica, além dos achados de imagens e implicações terapêuticas.

Cerebral vasomotor reactivity assessment using Transcranial Doppler and MRI with apnea test

Differently from previous studies that used Transcranial Doppler (TCD) and functional MRI (fMRI) for cerebral vasomotor reactivity (CVR) assessment in patients with carotid stenosis (CS), we assessed CVR using an identical stimulus, the Breath-Holding Test (BHT). We included 15 patients with CS and 7 age-matched controls to verify whether fMRI responded differently to BHT between groups and to calculate the agreement rate between tests. For TCD, impaired CVR was defined when the mean percentage increase on middle cerebral artery velocities was ≤31% on 3 consecutive 30-s apnea intercalated by 4-min normal breathing intervals. For fMRI, the percent variation on blood oxygen level-dependent (BOLD) signal intensity in the lentiform nucleus (LN) ipsilateral to the CS (or both LNs for controls) from baseline breathing to apnea was measured. The Euclidian differences between the series of each subject and the series of controls and patients classified it into normal or impaired CVR. We found different percent variations on BOLD-signal intensities between groups (P=0.032). The agreement was good in Controls (85.7%; κ=0.69) and overall (77.3%; κ=0.54). We conclude that BHT was feasible for CVR assessment on fMRI and elicited different BOLD responses in patients and controls, with a good overall agreement between the tests.

The Impact of Hemodialysis and Arteriovenous Access Flow on Extracranial Hemodynamic Changes in End-Stage Renal Disease Patients

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.

The Impact of Hemodialysis and Arteriovenous Access Flow on Extracranial Hemodynamic Changes in End-Stage Renal Disease Patients

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.

A New Flow-Diverter (the FloWise): In-Vivo Evaluation in an Elastase-Induced Rabbit Aneurysm Model

OBJECTIVE: We aimed to evaluate the efficacy and safety of a newly developed, partially retrievable flow-diverter (the FloWise) in an elastase-induced rabbit aneurysm model. MATERIALS AND METHODS: We developed a partially retrievable flow diverter composed of 48 strands of Nitinol and platinum wire. The FloWise is compatible with any microcatheter of 0.027-inch inner diameter, and is retrievable up to 70% deployment. The efficacy and safety of the FloWise were evaluated in the elastase-induced rabbit aneurysm model. The rate of technical success (full coverage of aneurysm neck) and assessment of aneurysm occlusion and stent patency was conducted by angiograms and histologic examinations at the 1-month, 3-month, and 6-month follow-up. The patency of small arterial branches (intercostal or lumbar arteries) covered by the FloWise were also assessed in the 5 subjects. RESULTS: We attempted FloWise insertion in a total of 32 aneurysm models. FloWise placement was successful in 31 subjects (96.9%). Two stents (6.2%) were occluded at the 3-month follow-up, but there was no evidence of in-stent stenosis in other subjects. All stented aneurysms showed progressive occlusion: grade I (complete aneurysm occlusion) in 44.4% and grade II (aneurysm occlusion > 90%) in 55.6% at 1 month; grade I in 90% and II in 10% at 3 months; and grade I in 90% and II in 10% at 6 months. All small arterial branches covered by the FloWise remained patent. CONCLUSION: A newly developed, partially retrievable flow-diverter seems to be a safe and effective tool of aneurysm occlusion, as evaluated in the rabbit aneurysm model.

Effect of volume replacement during combined experimental hemorrhagic shock and traumatic brain injury in prostanoids, brain pathology and pupil status / Efeito da reposição volêmica durante o choque hemorrágico combinado com traumatismo craniencefálico sobre prostanóides, patologia cerebral e status pupilar

Traumatic brain injury (TBI) is the main cause of trauma-related deaths. Systemic hypotension and intracranial hypertension causes cerebral ischemia by altering metabolism of prostanoids. We describe prostanoid, pupilar and pathological response during resuscitation with hypertonic saline solution (HSS) in TBI. Method Fifteen dogs were randomized in three groups according to resuscitation after TBI (control group; lactated Ringer’s (LR) group and HSS group), with measurement of thromboxane, prostaglandin, macroscopic and microscopic pathological evaluation and pupil evaluation.Result Concentration of prostaglandin is greater in the cerebral venous blood than in plasma and the opposite happens with concentration of thromboxane. Pathology revealed edema in groups with the exception of group treated with HSS.Discussion and conclusion There is a balance between the concentrations of prostaglandin and thromboxane. HSS prevented the formation of cerebral edema macroscopically detectable. Pupillary reversal occurred earlier in HSS group than in LR group.

O traumatismo cranioencefálico (TCE) é a principal causa de morte relacionada ao trauma. O choque hemorrágico e hipertensão intracraniana causam isquemia cerebral alterando o metabolismo de prostanóides. Neste estudo, relatamos o comportamento dos prostanóides, resposta pupilar e patologia durante a reposição volêmica com solução salina hipertônica (SSH) no TCE. Método Quinze cachorros foram randomizados em três grupos (controle, grupo de Ringer lactato e grupo de SSH) e foram avaliados tromboxane, prostaglandina, avaliação patológica macroscópica e microscópica e status pupilar.Resultado A concentração de prostaglandina é maior no sangue cerebral em comparação ao plasma, e o inverso ocorre com o tromboxane. A patologia revelou edema em todos os grupos, com exceção do grupo tratado com SSH.Discussão e conclusão Existe um equilíbrio entre concentrações cerebrais e plasmáticas de prostaglandina e tromboxane. A SSH protegeu o cérebro da formação de edema pós traumático.

Piribedil and Pathological Gambling in six Parkinsonian patients / Piribedil e Jogo Patológico em seis pacientes parkinsonianos

Impulse control disorders (ICD) in Parkinson's disease (PD) have attracted increasing interest. They are characterized by the inability to control the impulse to perform an act that can be detrimental to them or to others. Although dopamine agonists (DA), as a group, have been associated with impulse control disorders (ICD), piribedil has rarely been reported to cause them. Method Case reports of six parkinsonian patients on piribedil presenting pathological gambling (PG). Results All of the patients presented ICD associated with piribedil use. Two of them received this medication as first treatment and four of them who had developed ICDs secondary to other DA that reappeared with piribedil. Conclusion Despite piribedil is commercially available in only a few countries, it should be considered in the differential diagnosis of PG in patients with PD. .

Os distúrbios do controle do impulso (DCI) na doença de Parkinson (DP) têm atraído crescente interesse. Eles são caracterizados pela incapacidade da pessoa em controlar o impulso para realizar um ato que pode ser prejudicial a ela própria ou aos outros. Embora os agonistas dopaminérgicos (AD), como um grupo, têm sido associados com distúrbios do controle do impulso, o piribedil tem sido relatado raramente como causa dos mesmos. Método Relatos de seis casos de pacientes parkinsonianos em uso de piribedil apresentando jogo patológico (JP). Resultados Todos os pacientes apresentaram DCI com o uso do piribedil. Dois deles receberam piribedil como primeiro tratamento e quatro deles que haviam desenvolvido DCI devido a outro AD, reapresentaram o quadro com piribedil. Conclusão Apesar de o piribedil estar disponível comercialmente apenas em alguns países, deveria ser considerado no diagnóstico diferencial de JP em pacientes com DP. .

Descripción de los cambios en la velocidad media de flujo sanguíneo cerebral en posición supino y sedente, en pacientes con hemorragia subaracnoidea aneurismática con vasoespasmo asintomático o sin vasoespasmo: Serie de casos / Changes in cerebral blood flow velocity in supine and sitting position in patients with aneurysmal subarachnoid hemorrhage

Background: Early mobilization in intensive care units (ICU) provides respiratory, neurological and cardiovascular benefits in hospitalized patients. However, the orthostatic effects of changing from a supine to a sitting position may interfere with cerebral hemodynamics of patients with aneurysmal subarachnoid hemorrhage (aSAH). Aim: To describe the changes in mean cerebral blood flow velocity (MCBFV) in supine and sitting position, in adult patients with aSAH, with asymptomatic vasospasm (AVS) or without vasospasm (VS) at a neurosurgical ICU. Material and Methods: Descriptive case series study in 21 patients with aSAH, both with and without VS. They were positioned in a supine 30° position and then seated at the edge of bed for six minutes. MCBFV was measured by transcranial Doppler (TCD), and hemodynamic variables in both positions were registered. After this basal assessment and for 21 days after the episode of SAH, patients were seated once a day and signs of VS were recorded. Results: No significant changes in MCBFV or hemodynamic variables were detected during position changes, except for an increase in heart rate in the sitting position. No patient with AVS at the onset, had symptomatic VS during the 21 days of follow up when patients were seated. Among patients with a normal MCBFV at baseline, five patients (24%) had VS at a mean of three days after the first time that they were seated on the edge of bed. Conclusions: Sitting patients at the edge of the bed is a safe mobilization alternative for patients who suffered aSAH who did not have VS or had AVS.

Natural course of subarachnoid hemorrhage is worse in elderly patients / A história natural da hemorragia subaracnóide é pior em pacientes idosos

Aging is a major risk factor for poor outcome in patients with ruptured or unruptured intracranial aneurysms (IA) submitted to treatment. It impairs several physiologic patterns related to cerebrovascular hemodynamics and homeostasis. Objective Evaluate clinical, radiological patterns and prognostic factors of subarachnoid hemorrhage (SAH) patients according to age. Method Three hundred and eighty nine patients with aneurismal SAH from a Brazilian tertiary institution (Hospital do Servidor Público Estadual de São Paulo) were consecutively evaluated from 2002 to 2012 according to Fisher and Hunt Hess classifications and Glasgow Outcome Scale. Results There was statistically significant association of age with impaired clinical, radiological presentation and outcomes in cases of SAH. Conclusion Natural course of SAH is worse in elderly patients and thus, proper recognition of the profile of such patients and their outcome is necessary to propose standard treatment. .

A idade é considerada fator de risco de mau prognóstico em pacientes com aneurismas intracranianos rotos ou não-rotos; com o aumento da idade, ficam prejudicados vários padrões fisiológicos relacionados à hemodinâmica cerebral e homeostase. Objetivo Estudar o quadro clínico, os dados radiológicos e o prognóstico nos pacientes com hemorragia subaracnóide aneurismática em relação à idade. Método Foram avaliados consecutivamente, de 2002 a 2012, 389 pacientes com hemorragia subaracnóide aneurismática oriundos de uma instituição terciária brasileira. Resultados Houve associação da idade com pior quadro clínico, radiológico e prognóstico nos pacientes com hemorragia subaracnóide aneurismática. Conclusão O curso natural da hemorragia subaracnoidea é pior em pacientes idosos. O reconhecimento adequado do perfil desses pacientes e seu prognóstico é importante para estabelecer um tratamento adequado. .

Regional cerebral blood flow and cognitive function in patients with obsessive-compulsive disorder / Fluxo sanguineo regional cerebral e funcao cognitiva em pacientes com transtorno obsessivo compulsivo

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

Objetivo: Estudar a relação entre a perfusão sanguínea regional cerebral e as funções cognitivas em pacientes com transtorno obsessivo compulsivo (TOC). Método: Foram estudados 139 pacientes com TOC e 139 controles. As imagens do fluxo sanguíneo cerebral foram feitas por single photon emission computed tomography e o radioactivity rate (RAR) foi calculado usando como referência a radioatividade do córtex cerebelar. As funções cognitivas foram avaliadas através do Wisconsin Card Sorting Test (WCST). Resultados: O RAR do lobo pré-frontal, do lobo temporal anterior e do lobo occipital direito foram mais elevados nos pacientes do que nos controles (P<0.05). Quanto ao WCST, os escores de números corretos (P<0.01) e de classificação (P<0.05) foram menores no grupo TOC do que nos controles; entretanto, os escores de erros e de erros persistentes nos controles foram mais elevados do que nos pacientes (P<0.01). O RAR do lobo pré-frontal direito estava relacionado de modo negativo com os números corretos; o RAR do lobo temporal anterior apresentava correlação positiva com os erros; o RAR do lobo pré-frontal direito e do tálamo esquerdo apresentavam correlação positiva com erros persistentes. Conclusão: Pacientes com TOC apresentaram perfusão sanguínea cerebral mais intensa no lobo pré-frontal e no lobo temporal anterior. O lobo pré-frontal direito, o lobo temporal e o tálamo esquerdo podem estar relacionados com alterações cognitivas. .

True Progression versus Pseudoprogression in the Treatment of Glioblastomas: A Comparison Study of Normalized Cerebral Blood Volume and Apparent Diffusion Coefficient by Histogram Analysis

OBJECTIVE: The purpose of this study was to differentiate true progression from pseudoprogression of glioblastomas treated with concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ) by using histogram analysis of apparent diffusion coefficient (ADC) and normalized cerebral blood volume (nCBV) maps. MATERIALS AND METHODS: Twenty patients with histopathologically proven glioblastoma who had received CCRT with TMZ underwent perfusion-weighted imaging and diffusion-weighted imaging (b = 0, 1000 sec/mm2). The corresponding nCBV and ADC maps for the newly visible, entirely enhancing lesions were calculated after the completion of CCRT with TMZ. Two observers independently measured the histogram parameters of the nCBV and ADC maps. The histogram parameters between the true progression group (n = 10) and the pseudoprogression group (n = 10) were compared by use of an unpaired Student's t test and subsequent multivariable stepwise logistic regression analysis to determine the best predictors for the differential diagnosis between the two groups. Receiver operating characteristic analysis was employed to determine the best cutoff values for the histogram parameters that proved to be significant predictors for differentiating true progression from pseudoprogression. Intraclass correlation coefficient was used to determine the level of inter-observer reliability for the histogram parameters. RESULTS: The 5th percentile value (C5) of the cumulative ADC histograms was a significant predictor for the differential diagnosis between true progression and pseudoprogression (p = 0.044 for observer 1; p = 0.011 for observer 2). Optimal cutoff values of 892 x 10-6 mm2/sec for observer 1 and 907 x 10-6 mm2/sec for observer 2 could help differentiate between the two groups with a sensitivity of 90% and 80%, respectively, a specificity of 90% and 80%, respectively, and an area under the curve of 0.880 and 0.840, respectively. There was no other significant differentiating parameter on the nCBV histograms. Inter-observer reliability was excellent or good for all histogram parameters (intraclass correlation coefficient range: 0.70-0.99). CONCLUSION: The C5 of the cumulative ADC histogram can be a promising parameter for the differentiation of true progression from pseudoprogression of newly visible, entirely enhancing lesions after CCRT with TMZ for glioblastomas.

Cerebral hemodynamics: concepts of clinical importance / Hemodinâmica encefálica: conceitos de importância clínica

Cerebral hemodynamics and metabolism are frequently impaired in a wide range of neurological diseases, including traumatic brain injury and stroke, with several pathophysiological mechanisms of injury. The resultant uncoupling of cerebral blood flow and metabolism can trigger secondary brain lesions, particularly in early phases, consequently worsening the patient's outcome. Cerebral blood flow regulation is influenced by blood gas content, blood viscosity, body temperature, cardiac output, altitude, cerebrovascular autoregulation, and neurovascular coupling, mediated by chemical agents such as nitric oxide (NO), carbon monoxide (CO), eicosanoid products, oxygen-derived free radicals, endothelins, K+, H+, and adenosine. A better understanding of these factors is valuable for the management of neurocritical care patients. The assessment of both cerebral hemodynamics and metabolism in the acute phase of neurocritical care conditions may contribute to a more effective planning of therapeutic strategies for reducing secondary brain lesions. In this review, the authors have discussed concepts of cerebral hemodynamics, considering aspects of clinical importance.

Alterações hemodinâmicas e metabólicas do encéfalo ocorrem frequentemente em diversas doenças neurológicas, principalmente em condições de traumatismo cranioencefálico e acidente vascular encefálico, com vários mecanismos patofisiológicos lesionais. O desacoplamento resultante do fluxo sanguíneo e do metabolismo encefálico pode resultar em lesões encefálicas secundárias, principalmente nas primeiras fases, e, consequentemente, no agravamento do desfecho neurológico dos pacientes. Diversos fatores influenciam o fluxo sanguíneo encefálico, entre eles, a concentração sanguínea de gases, viscosidade sanguínea, temperatura corpórea, débito cardíaco, altitude, autorregulação cerebrovascular e acoplamento neurovascular, que é mediado por óxido nítrico (ON), monóxido de carbono (CO), eicosanoides, radicais livres derivados do oxigênio, endotelinas, potássio, íons hidrogênio e adenosinas. Melhor compreensão destes fatores é fundamental para o manejo clínico dos pacientes neurológicos críticos. A avaliação hemodinâmica e metabólica do encéfalo nas lesões encefálicas agudas pode contribuir para o planejamento de estratégias de redução das lesões encefálicas secundárias. Nesta revisão, os autores discutiram princípios da hemodinâmica encefálica, considerando os aspectos de importância clínica.

Correlação entre a SvO2 e SjO2 durante a cirurgia cardíaca com circulação extracorpórea em crianças / SjO2/SvO2 correlation during pediatric cardiac surgery with cardiopulmonary bypass

OBJETIVOS: Analisar a correlação entre a SvO2 (indicador do débito cardíaco) e a SjO2 (indicador da oxigenação cerebral) durante cirurgias cardíacas com circulação extracorpórea (CEC) em crianças. MÉTODOS: Estudo retrospectivo. Dados da SjO2, SvO2 e SaO2, mensurados simultaneamente em momentos críticos da cirurgia cardíaca com CEC, em 12 crianças, foram analisados pelo teste de correlação de Spearman e pela representação gráfica de Bland-Altman. RESULTADOS: Foram encontrados baixa correlação entre a SjO2 e a SvO2 (r²=0,14, P=0,03) e um viés alto (-7,8) na plotagem de Bland-Altman, indicando independência entre as duas variáveis. SjO2 < 50 por cento (indicativo de isquemia-hipoxia cerebral) foi observada em cerca de 50 por cento das medidas após o reaquecimento no final da CEC hipotérmica. CONCLUSÕES: A medida de SvO2 não é preditiva da SjO2 durante a cirurgia cardíaca com CEC em crianças e baixa SjO2 pode deixar de ser detectada medindo-se apenas a SvO2.

OBJECTIVES: To compare the SjO2 (cerebral oxygenation indicator) and SvO2 (cardiac output indicator) during pediatric cardiac surgery with cardiopulmonary bypass (CPB). METHODS: Retrospective study. Data of SjO2 and SvO2 measured simultaneously at critical time periods during cardiac surgery with CPB were analyzed by the Spearman correlation test and Bland- Altman plot. RESULTS:Regression analysis of the pooled data showed poor correlation between SjO2 and SvO2 (r²=0.14, P=0.03) and Bland- Altman plot had a high bias (-7.9), indicating independency of the two variables. SjO2<50 percent (indicative of cerebral ischemia-hypoxia) were observed in 50 percent of the measurements after rewarming during hypothermic CPB. CONCLUSIONS: SvO2 is not a good predictor of SjO2 during pediatric cardiac surgery with CPB, and low SjO2 can be undetected measuring SvO2 only.