RESUMO
BACKGROUND AND PURPOSE: Ipsilateral thalamic diaschisis (ITD) describes the reduction of thalamic function, metabolism, and perfusion resulting from a distant lesion of the ipsilateral hemisphere. Our aim was to evaluate the perfusion characteristics and clinical impact of ITD in acute middle cerebral artery stroke, which does not directly affect the thalamus. METHODS: One hundred twenty-four patients with middle cerebral artery infarction were selected from a prospectively acquired cohort of 1644 patients who underwent multiparametric computed tomography (CT), including CT perfusion for suspected stroke. Two blinded readers evaluated the occurrence of ITD, defined as ipsilateral thalamic hypoperfusion present on ≥2 CT perfusion maps. Perfusion alterations were defined according to the Alberta Stroke Program Early CT Score regions. Final infarction volume and subacute complications were assessed on follow-up imaging. Clinical outcome was quantified using the modified Rankin Scale. Multivariable linear and ordinal logistic regression analysis were applied to identify independent associations. RESULTS: ITD was present in 25/124 subjects (20.2%, ITD+). In ITD+ subjects, perfusion of the caudate nucleus, internal capsule, and lentiform nucleus was more frequently affected than in ITD- patients (each with P<0.001). In the ITD+ group, larger cerebral blood flow (P=0.002) and cerebral blood volume (P<0.001) deficit volumes, as well as smaller cerebral blood flow-cerebral blood volume mismatch (P=0.021) were observed. There was no independent association of ITD with final infarction volume or clinical outcome at discharge in treatment subgroups (each with P>0.05). ITD had no influence on the development of subacute stroke complications. CONCLUSIONS: ITD in the form of thalamic hypoperfusion is a frequent CT perfusion finding in the acute phase in middle cerebral artery stroke patients with marked involvement of subcortical areas. ITD does not result in thalamic infarction and had no independent impact on patient outcome. Notably, ITD was misclassified as part of the ischemic core by automated software, which might affect patient selection in CT perfusion-based trials.
Assuntos
Isquemia Encefálica/diagnóstico por imagem , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Doenças Talâmicas/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/etiologia , Isquemia Encefálica/fisiopatologia , Estudos de Casos e Controles , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Circulação Cerebrovascular , Corpo Estriado/irrigação sanguínea , Corpo Estriado/diagnóstico por imagem , Feminino , Humanos , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/fisiopatologia , Cápsula Interna/irrigação sanguínea , Cápsula Interna/diagnóstico por imagem , Modelos Lineares , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Imagem de Perfusão , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia , Doenças Talâmicas/etiologia , Doenças Talâmicas/fisiopatologia , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND AND PURPOSE: To assess the effect of unilateral large vessel disease upon the cerebral hemodynamic autoregulatory status in the basal ganglia of patients with steno-occlusive internal carotid artery (ICA) disease. MATERIALS AND METHODS: Twenty-five healthy volunteers and 38 patients with a unilateral symptomatic steno-occlusive ICA lesion and were investigated; 20 with a stenosis >50% and 18 with an occlusion. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were assessed with pseudo-continuous arterial spin labeling (ASL) magnetic resonance (MR) imaging before and after administration of acetazolamide. RESULTS: When compared to controls, the CVR in patients with ICA stenosis was significantly lower in the middle cerebral artery (MCA) territory (P<0.05), and in the caudate (P<0.05) and lentiform nucleus (P<0.05) of the hemisphere ipsilateral to the stenosis. The CVR in the caudate nucleus contralateral to the stenosis was significantly lower (P<0.05) as well. In patients with ICA occlusion, the CVR in the hemisphere ipsilateral to the occlusion as well as in the contralateral hemisphere was significantly lower in the MCA territory (P<0.05), the caudate (P<0.05) and lentiform nucleus (P<0.05), and in the thalamus (P<0.05). CONCLUSION: Perfusion ASL MR imaging shows impaired cerebral hemodynamic autoregulation of the basal ganglia in patients with steno-occlusive ICA disease both in the hemisphere ipsilateral as well as in the hemisphere contralateral to the stenosis or occlusion.
Assuntos
Doenças das Artérias Carótidas/diagnóstico por imagem , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Corpo Estriado/irrigação sanguínea , Corpo Estriado/diagnóstico por imagem , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagem , Acetazolamida/administração & dosagem , Idoso , Doenças das Artérias Carótidas/complicações , Circulação Cerebrovascular , Meios de Contraste/administração & dosagem , Feminino , Humanos , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Marcadores de SpinRESUMO
BACKGROUND: The brain reserve hypothesis posits that there are individual differences in the ability to cope with brain pathology, and that brain damage extent and clinical symptoms are not tightly linked. If cognitive reserve hypothesis has been demonstrated in Alzheimer Disease and Frontotemporal Dementia (FTD), no evidence of reserve mechanisms on behavioural disturbances has been corroborated yet. In FTD, distinct behavioural phenotypes may be identified. OBJECTIVE: To test the behavioural reserve hypothesis in behavioural variant FTD (bvFTD). METHODS: As previously demonstrated, bvFTD patients were grouped into four behavioural phenotypes, i.e. "disinhibited", "apathetic", "language", and "aggressive", by means of Confirmatory Factor Analysis on behavioural assessment. Educational achievement was considered as proxy measure of reserve on behavioural disturbances, and cerebral SPECT as an indirect expression of brain pathology. On each group, the effect of education on brain damage was assessed by slope analysis. RESULTS: A specific effect of education attainment on "disinhibited" phenotype was observed, the higher the education, the greater the hypoperfusion in the right inferior frontal gyrus and the left medial frontal gyrus and right caudate (P<0.001). On the other behavioural phenotypes, no effect of education was reported in modulating brain damage. CONCLUSIONS: We suggest that in neurodegenerative diseases the concept of brain reserve might be extended, as compensatory mechanisms are in action not only for cognitive deficits but for behavioural disturbances as well.
Assuntos
Comportamento/fisiologia , Reserva Cognitiva/fisiologia , Demência Frontotemporal/psicologia , Idoso , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Cisteína/análogos & derivados , Escolaridade , Análise Fatorial , Feminino , Lobo Frontal/irrigação sanguínea , Lobo Frontal/diagnóstico por imagem , Demência Frontotemporal/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Compostos de Organotecnécio , Compostos Radiofarmacêuticos , Análise de Regressão , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
This article investigates the effects of postherpetic neuralgia (PHN) on resting-state brain activity utilizing arterial spin labeling (ASL) techniques. Features of static and dynamic cerebral blood flow (CBF) were analyzed to reflect the specific brain response to PHN pain. Eleven consecutive patients suffering from PHN and 11 age- and gender-matched control subjects underwent perfusion functional magnetic resonance imaging brain scanning during the resting state. Group comparison was conducted to detect the regions with significant changes of CBF in PHN patients. Then we chose those regions that were highly correlated with the self-reported pain intensity as "seeds" to calculate the functional connectivity of both groups. Absolute CBF values of these regions were also compared across PHN patients and control subjects. Significant increases in CBF of the patient group were observed in left striatum, right thalamus, left primary somatosensory cortex (S1), left insula, left amygdala, left primary somatomotor cortex, and left inferior parietal lobule. Significant decreases in CBF were mainly located in the frontal cortex. Regional CBF in the left caudate, left insula, left S1, and right thalamus was highly correlated with the pain intensity, and further comparison showed that the regional CBF in these regions is significantly higher in PHN groups. Functional connectivity results demonstrated that the reward circuitry involved in striatum, prefrontal cortex, amygdala, and parahippocampal gyrus and the circuitry among striatum, thalamus, and insula were highly correlated with each element in PHN patients. In addition, noninvasive brain perfusion imaging at rest may provide novel insights into the central mechanisms underlying PHN pain.
Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Conectoma/métodos , Imageamento por Ressonância Magnética , Neuralgia Pós-Herpética/fisiopatologia , Idoso , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/irrigação sanguínea , Córtex Motor/fisiologia , Lobo Parietal/irrigação sanguínea , Lobo Parietal/fisiologia , Córtex Pré-Frontal/irrigação sanguínea , Córtex Pré-Frontal/fisiologia , Córtex Somatossensorial/irrigação sanguínea , Córtex Somatossensorial/fisiologia , Tálamo/irrigação sanguínea , Tálamo/fisiologiaRESUMO
OBJECTIVE: To investigate the influence of internal carotid artery (ICA) stenosis on the distribution of blood flow to the caudate nucleus, lentiform nucleus, and thalamus. METHODS: We studied 18 healthy control subjects, 20 patients with a unilateral asymptomatic ICA stenosis, and 15 patients with a recently symptomatic unilateral ICA stenosis. The contribution of the ICAs and the basilar artery to the perfusion of the deep brain structures was assessed by perfusion territory selective arterial spin labeling (ASL) MRI. Differences were tested with a two-tailed Fishers' exact test. RESULTS: The caudate nucleus was predominantly supplied with blood by the ipsilateral ICA in all groups. In 4 of the 15 (27%) the symptomatic patients, the caudate nucleus partially received blood from the contralateral ICA, compared to none of the 18 healthy control subjects (p = 0.03). The lentiform nucleus and the thalamus were predominantly supplied with blood by the ipsilateral ICA and basilar artery respectively in all groups. CONCLUSION: In patients with a symptomatic ICA stenosis, the caudate nucleus may be supplied with blood by the contralateral ICA more often than in healthy controls.
Assuntos
Estenose das Carótidas/patologia , Núcleo Caudado/patologia , Circulação Cerebrovascular , Corpo Estriado/patologia , Tálamo/patologia , Idoso , Gânglios da Base/patologia , Núcleo Caudado/irrigação sanguínea , Constrição Patológica , Corpo Estriado/irrigação sanguínea , Feminino , Hemodinâmica , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Perfusão , Tálamo/irrigação sanguíneaRESUMO
We have studied a number of long-term meditators in previous studies. The purpose of this study was to determine if there are differences in baseline brain function of experienced meditators compared to non-meditators. All subjects were recruited as part of an ongoing study of different meditation practices. We evaluated 12 advanced meditators and 14 non-meditators with cerebral blood flow (CBF) SPECT imaging at rest. Images were analyzed with both region of interest and statistical parametric mapping. The CBF of long-term meditators was significantly higher (p<.05) compared to non-meditators in the prefrontal cortex, parietal cortex, thalamus, putamen, caudate, and midbrain. There was also a significant difference in the thalamic laterality with long-term meditators having greater asymmetry. The observed changes associated with long-term meditation appear in structures that underlie the attention network and also those that relate to emotion and autonomic function.
Assuntos
Encéfalo/irrigação sanguínea , Processamento de Imagem Assistida por Computador , Meditação/psicologia , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Núcleo Caudado/irrigação sanguínea , Dominância Cerebral/fisiologia , Feminino , Humanos , Masculino , Mesencéfalo/irrigação sanguínea , Pessoa de Meia-Idade , Lobo Parietal/irrigação sanguínea , Córtex Pré-Frontal/irrigação sanguínea , Putamen/irrigação sanguínea , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia , Tálamo/irrigação sanguínea , Adulto JovemRESUMO
PURPOSE: To investigate the effect of variations in anatomic features of the circle of Willis on the perfusion territory to deep structures, including the nucleus caudatus, the nucleus lentiformis, and the thalamus. MATERIALS AND METHODS: The ethics committee of the study institution approved the study protocol. A total of 159 patients with first-time clinical symptoms of cerebral ischemia were recruited. Contributions to the perfusion territory were visualized with territorial arterial spin-labeling magnetic resonance (MR) imaging. The anatomic features of the circle of Willis were evaluated with time-of-flight MR angiography. Perfusion territory contributions were compared among circle of Willis variants by using the Cochran-Mantel-Haenszel test. RESULTS: The perfusion territory contributions to the deep-brain structures could be evaluated in 119 of 159 patients (75%). With a fetal-type circle of Willis (41 of 238 hemispheres; 17%), there was a contribution from the ipsilateral internal carotid artery to the thalamus in all 41 hemispheres (100%), compared with 96 of the 197 hemispheres (49%) without a fetal-type circle of Willis. In the 19 patients with a hypoplastic A1 segment, there was more often a contribution of the contralateral internal carotid artery to the perfusion of the nucleus caudatus (10 of 19; 53%) and the nucleus lentiformis (5 of 19; 26%). CONCLUSION: The perfusion territory contributions to deep-brain structures vary widely. These differences can be partly explained by variations in the anatomic features of the circle of Willis. (c) RSNA, 2010.
Assuntos
Núcleo Caudado/irrigação sanguínea , Circulação Cerebrovascular , Corpo Estriado/irrigação sanguínea , Angiografia por Ressonância Magnética/métodos , Tálamo/irrigação sanguínea , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Modelos Lineares , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Marcadores de SpinAssuntos
Isquemia Encefálica/patologia , Veias Cerebrais/patologia , Trombose Intracraniana/patologia , Doenças Talâmicas/patologia , Tálamo/patologia , Trombose Venosa/patologia , Anticoagulantes , Isquemia Encefálica/etiologia , Isquemia Encefálica/fisiopatologia , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/patologia , Núcleo Caudado/fisiopatologia , Veias Cerebrais/fisiopatologia , Transtornos da Consciência/etiologia , Diagnóstico Precoce , Feminino , Lateralidade Funcional/fisiologia , Heparina/uso terapêutico , Humanos , Trombose Intracraniana/complicações , Trombose Intracraniana/fisiopatologia , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Doenças Talâmicas/etiologia , Doenças Talâmicas/fisiopatologia , Tálamo/irrigação sanguínea , Tálamo/fisiopatologia , Resultado do Tratamento , Trombose Venosa/complicações , Trombose Venosa/fisiopatologiaRESUMO
OBJECTIVE: In multiple sclerosis (MS), an early neurodegenerative affection of subcortical gray matter has been suggested. Transcranial sonography (TCS) shows hyperechogenic lesions of substantia nigra (SN) and basal ganglia, thought to reflect iron accumulation, in a number of primary neurodegenerative diseases. The present study deals with the question of whether TCS can also display deep gray matter lesions in patients with MS and whether sonographic findings relate to severity and progression of MS. METHODS: We prospectively studied 75 patients with different courses of MS and 55 age-matched healthy subjects clinically and with TCS. Twenty-three patients additionally had 1.5-T MRI at the time of TCS. Disease progression was assessed clinically 2 years after TCS. RESULTS: Abnormal hyperechogenicity of SN, lenticular nucleus (LN), caudate nucleus, and thalamus was found in 41%, 54%, 40%, and 8% of the patients with MS, with similar frequency in patients with relapsing-remitting and primary or secondary progressive MS if corrected for disease duration, but only in 13%, 13%, 5% (each, p < 0.001), and none (p = 0.028) of the control subjects. Hyperechogenicity of SN and LN correlated with more pronounced MRI T2 hypointensity, thought to reflect iron deposition. Larger bilateral SN echogenic area was related to higher rate of disease progression, whereas small SN echogenic area (SN hypoechogenicity) predicted a disease course without further progression within 2 years. CONCLUSIONS: Neurodegenerative disease-like deep gray matter lesions can be frequently detected by transcranial sonography (TCS) in patients with multiple sclerosis (MS). Findings suggest that TCS shows changes of brain iron metabolism which correlate with future progress of MS.
Assuntos
Circulação Cerebrovascular , Esclerose Múltipla Crônica Progressiva/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Prosencéfalo/irrigação sanguínea , Prosencéfalo/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana , Adulto , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Corpo Estriado/irrigação sanguínea , Corpo Estriado/diagnóstico por imagem , Progressão da Doença , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Crônica Progressiva/patologia , Esclerose Múltipla Recidivante-Remitente/patologia , Valor Preditivo dos Testes , Estudos Prospectivos , Índice de Gravidade de Doença , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagemRESUMO
OBJECT: The mechanisms underlying deafferentation pain are not well understood. Motor cortex stimulation (MCS) is useful in the treatment of this kind of chronic pain, but the detailed mechanisms underlying its effects are unknown. METHODS: Six patients with intractable deafferentation pain in the left hand were included in this study. All were righthanded and had a subdural electrode placed over the right precentral gyrus. The pain was associated with brainstem injury in one patient, cervical spine injury in one patient, thalamic hemorrhage in one patient, and brachial plexus avulsion in three patients. Treatment with MCS reduced pain; visual analog scale (VAS) values for pain were 82 +/- 20 before MCS and 39 +/- 20 after MCS (mean +/- standard error). Regional cerebral blood flow (rCBF) was measured by positron emission tomography with H2(15)O before and after MCS. The obtained images were analyzed with statistical parametric mapping software (SPM99). RESULTS: Significant rCBF increases were identified after MCS in the left posterior thalamus and left insula. In the early post-MCS phase, the left posterior insula and right orbitofrontal cortex showed significant rCBF increases, and the right precentral gyrus showed an rCBF decrease. In the late post-MCS phase, a significant rCBF increase was detected in the left caudal part of the anterior cingulate cortex (ACC). CONCLUSIONS: These results suggest that MCS modulates the pathways from the posterior insula and orbitofrontal cortex to the posterior thalamus to upregulate the pain threshold and pathways from the posterior insula to the caudal ACC to control emotional perception. This modulation results in decreased VAS scores for deafferentation pain.
Assuntos
Córtex Cerebral/anatomia & histologia , Córtex Cerebral/fisiopatologia , Estimulação Encefálica Profunda/instrumentação , Córtex Motor/fisiopatologia , Manejo da Dor , Tálamo/fisiopatologia , Idoso , Lesões Encefálicas/complicações , Lesões Encefálicas/fisiopatologia , Tronco Encefálico/irrigação sanguínea , Tronco Encefálico/lesões , Tronco Encefálico/fisiopatologia , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/fisiopatologia , Córtex Cerebral/irrigação sanguínea , Circulação Cerebrovascular/fisiologia , Feminino , Giro do Cíngulo/irrigação sanguínea , Giro do Cíngulo/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/irrigação sanguínea , Dor/diagnóstico , Dor/etiologia , Medição da Dor , Tomografia por Emissão de Pósitrons , Índice de Gravidade de Doença , Traumatismos da Coluna Vertebral/complicações , Traumatismos da Coluna Vertebral/fisiopatologia , Tálamo/irrigação sanguíneaRESUMO
PURPOSE: The aim of our study was to assess the regional cerebral blood flow (rCBF) of basal ganglia and thalami in patients with Parkinson's disease (PD) using perfusion-weighted magnetic resonance imaging (PW-MRI). MATERIAL AND METHODS: Twenty subjects affected by idiopathic PD according to the United Kingdom Brain Bank criteria were enrolled in the study. Twenty normal subjects matched for age and gender were included as controls. After 20-day therapy withdrawal, the PD patients underwent PW-MRI. The rCBF was calculated both in patients and in controls. The regions of interest were manually positioned on rCBF maps over the caudate nucleus, the putamen, the external and internal globus pallidus, and over the ventrolateral nucleus of the thalamus. Data were normalised with those obtained from parieto-occipital white matter (POWM). Statistical analysis was performed using a parametric ANOVA test. RESULTS: Patients showed a significant (p<0.01) interhemispheric asymmetry; rCBF values were higher on the more severely affected side. Controls showed no interhemispheric asymmetry. CONCLUSION: Our study suggests that PW-MRI is a valuable tool for assessing haemodynamic changes in PD patients. Haemodynamic change pattern may be useful in the early diagnosis of PD.
Assuntos
Gânglios da Base/irrigação sanguínea , Circulação Cerebrovascular/fisiologia , Imageamento por Ressonância Magnética/métodos , Doença de Parkinson/fisiopatologia , Idoso , Estudos de Casos e Controles , Núcleo Caudado/irrigação sanguínea , Meios de Contraste , Feminino , Gadolínio DTPA , Globo Pálido/irrigação sanguínea , Humanos , Aumento da Imagem/métodos , Masculino , Lobo Occipital/irrigação sanguínea , Lobo Parietal/irrigação sanguínea , Putamen/irrigação sanguínea , Tálamo/irrigação sanguínea , Núcleos Ventrais do Tálamo/irrigação sanguíneaRESUMO
Clinical and neuropsychological study of 28 patients with arteriovenous malformations (AVM) of the caudate nucleus and 36 patients with AVM of the thalamus has been conducted. After surgical removal of the caudate nucleus, speech disturbances developed in 4 out of 8 patients with left-side AVM and in 1 patient, a converted left-hander, with right-side AVM. All 5 patients had mild speech disturbances, which differed by character in dependence of the AVM location. In case of AVM location in the head of the caudate nucleus, the speech disturbances were represented by perseverations and were similar to those caused by the lesion in the Broca area. In case of the caudate nucleus lesion, naming was mildly affected that resembled temporal aphasia. After surgical removal of AVM in the left thalamus in 9 patients, complex and rather stable speech disturbances developed in 7 cases. They were featured by the signs of frontal and temporal aphasias, i.e. there were perseverations and disturbances of naming, auditory and speech memory. The peculiarities of speech disturbances in lesions of the caudate nucleus and the thalamus were well explained by their anatomic and functional correlations with different regions of brain speech cortex. Speech disturbances in various subcortical lesions are reviewed. In the authors' opinion, subcortical aphasias do not have any particular character but include the same factors in different combinations as cortical ones that is determined by the presence of common functional systems for speech support which comprise cortical and subcortical patterns.
Assuntos
Afasia/etiologia , Núcleo Caudado/irrigação sanguínea , Malformações Arteriovenosas Intracranianas/complicações , Tálamo/irrigação sanguínea , Adolescente , Adulto , Afasia/diagnóstico , Núcleo Caudado/cirurgia , Angiografia Cerebral , Criança , Feminino , Humanos , Malformações Arteriovenosas Intracranianas/diagnóstico , Malformações Arteriovenosas Intracranianas/cirurgia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Índice de Gravidade de Doença , Tálamo/cirurgiaRESUMO
Despite the recent rise in oral methylphenidate (MPH) abuse, few studies have characterized the time course of oral MPH brain effects in human subjects. Accordingly, this study assessed the hemodynamic effects of oral MPH effects in 11 healthy young adults (six women), by measuring brain transverse relaxation times (T2). T2 can be interpreted as a surrogate marker for, and inversely correlated with, steady-state cerebral blood volume (CBV). Data were acquired from the caudate nucleus, putamen, and thalamus, using a 1.5 T MRI scanner at baseline and serially for 2 h following oral MPH administration (0.5 mg/kg). Physiological and subjective measures and plasma MPH levels also were examined. MPH induced a selective T2 decrease (-1.65+/-0.53 ms) in the putamen (F(6,54)=2.68, P<0.03). Heartrate, blood pressure and plasma MPH levels increased significantly after drug administration, as well as subjective ratings of "feeling drug effect". T2 decreases may reflect MPH-induced increases in putaminal blood volume. These data suggest that T2 relaxometry can be used to study the time course of regional cerebral blood volume responses to MPH and perhaps to other stimulant drugs.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Drogas Ilícitas/farmacologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Metilfenidato/farmacologia , Putamen/irrigação sanguínea , Putamen/efeitos dos fármacos , Administração Oral , Adulto , Afeto/efeitos dos fármacos , Gânglios da Base/irrigação sanguínea , Gânglios da Base/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacocinética , Dominância Cerebral/fisiologia , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Drogas Ilícitas/farmacocinética , Masculino , Metilfenidato/farmacocinética , Fluxo Sanguíneo Regional/fisiologia , Transmissão Sináptica/efeitos dos fármacos , Tálamo/irrigação sanguínea , Tálamo/efeitos dos fármacosRESUMO
PURPOSE: Ictal-interictal single-photon emission computed tomography (SPECT) subtraction was performed to find brain structures related to ictal dystonic posturing (DP) in patients with temporal lobe epilepsy (TLE). METHODS: Thirty-two patients with mesial TLE who had ictal and interictal SPECTs were included. They were divided into two groups; DP group with ictal dystonia during ictal SPECT (n = 15) and Non-DP group without ictal DP (n = 17). Ictal-interictal SPECT subtraction was performed, and then subtracted SPECT was coregistered with brain spoiled gradient recalled (SPGR) magnetic resonance imaging (MRI). The ictal hyperperfusion on subtracted SPECT was analyzed in basal ganglia, frontal cortex, thalamus, temporal lobe, and insular cortex. RESULTS: The incidences of ictal hyperperfusion on brain regions in DP versus Non-DP groups were 80.0% (12 of 15 patients) versus none (0 of 17), p = 0.001, chi2, in caudate nucleus; 93.3% (14 of 15) versus 47.0% (eight of 17), p = 0.005, in putamen; and 80.0% (12 of 15) versus 41.2% (seven of 17), p = 0.026, in thalamus. No significant difference of ictal hyperperfusion was found in globus pallidus, temporal lobes, insular and frontal cortices between DP and Non-DP groups. DP patients showed an earlier age at seizure onset [8.6 years (DP) vs. 15.7 years (Non-DP) (p = 0.015)] and a longer duration of seizure history [19.0 years (DP) vs. 11.9 years (Non-DP) (p = 0.015)]. CONCLUSIONS: Caudate nucleus, putamen, and thalamus were significantly related to the ictal DP during TLE seizures. Our study showed first an active involvement of the caudate nucleus in the generation of ictal DP.
Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Distonia/diagnóstico por imagem , Epilepsia do Lobo Temporal/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Gânglios da Base/irrigação sanguínea , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/fisiopatologia , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Núcleo Caudado/fisiopatologia , Distonia/diagnóstico , Distonia/fisiopatologia , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Putamen/irrigação sanguínea , Putamen/diagnóstico por imagem , Putamen/fisiopatologia , Compostos Radiofarmacêuticos , Fluxo Sanguíneo Regional/fisiologia , Técnica de Subtração , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagem , Tálamo/fisiopatologiaRESUMO
Regional cerebral blood flow (CBF) was studied with O(15)-water positron emission tomography and anatomic region-of-interest analysis on co-registered magnetic resonance in patients with idiopathic (n = 12) and secondary (n = 5) normal pressure hydrocephalus (NPH). Mean CBF was compared with values obtained from healthy volunteers (n = 12) and with clinical parameters. Mean CBF was significantly decreased in the cerebrum and cerebellum of patients with NPH. The regional analysis demonstrated that CBF was reduced in the basal ganglia and the thalamus but not in white matter regions. The results suggest that the role of the basal ganglia and thalamus in NPH may be more prominent than currently appreciated. The implications for theories regarding the pathogenesis of NPH are discussed.
Assuntos
Circulação Cerebrovascular/fisiologia , Hidrocefalia de Pressão Normal/fisiopatologia , Idoso , Núcleo Caudado/irrigação sanguínea , Feminino , Humanos , Hidrocefalia de Pressão Normal/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Radioisótopos de Oxigênio , Putamen/irrigação sanguínea , Valores de Referência , Tálamo/irrigação sanguínea , Tomografia Computadorizada de EmissãoRESUMO
OBJECTIVE: This study, part of a continuing effort to understand the pathophysiology of the brain in early-onset anorexia nervosa, attempts to validate findings from an earlier study of regional cerebral blood flow and to correlate any abnormalities in blood flow with eating disorder psychopathology. METHOD: Fifteen newly referred children and adolescents with a diagnosis of anorexia nervosa (AN) underwent regional cerebral blood flow (rCBF) examination using single-photon computerized tomography (SPECT) and the Eating Disorders Examination (EDE) for children. RESULTS: Mean age was 14 years 11 months (SD = 1.35). Mean weight for height ratio was 82.79 % (SD = 10.66). SPECT findings showed that 11 (73%) had asymmetry (hypoperfusion) of blood flow in at least one area. Regions of the brain showing hypoperfusion included the temporal lobe (n = 9), parietal lobe (n = 5), frontal lobe (n = 3), thalamus (n = 3), and the caudate nuclei (n = 1). The median EDE subscale scores were high for all four subscales. Those patients with hypoperfusion had higher median EDE subscale scores than those without hypoperfusion, although the differences were not statistically significant. CONCLUSIONS: Most patients in our study had abnormal rCBF, predominantly affecting the temporal lobe, confirming our previous findings. There was no association with the EDE scores. The findings support earlier suggestions of an imbalance in neural pathways or circuits, possibly within the limbic system. This hypothesis is considered within the context of current knowledge and suggestions made with regard to how it might be tested.
Assuntos
Anorexia Nervosa/diagnóstico por imagem , Encéfalo/irrigação sanguínea , Dominância Cerebral/fisiologia , Sistema Límbico/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Adolescente , Anorexia Nervosa/fisiopatologia , Peso Corporal/fisiologia , Encéfalo/diagnóstico por imagem , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/diagnóstico por imagem , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/diagnóstico por imagem , Criança , Feminino , Humanos , Sistema Límbico/fisiopatologia , Rede Nervosa/fisiopatologia , Vias Neurais/fisiopatologia , Fluxo Sanguíneo Regional/fisiologia , Reprodutibilidade dos Testes , Lobo Temporal/irrigação sanguínea , Lobo Temporal/diagnóstico por imagem , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagemRESUMO
Clinical-neuropsychological investigations were performed in 187 patients with arteriovenous malformations (AVM) of deep brain structures; 28 had AVM of the caudate nucleus, 35 of the thalamus, 45 of the cingulate gyrus, 43 of the hippocampus, and 36 of the corpus callosum. A total of 47 patients displayed neglect phenomena of different modalities, while unfixed neglect was demonstrated in 40 cases using special tests. The vast majority of patients showed neglect of left-sided space and the left side of the body, while only three patients showed right-sided neglect. These three patients had signs of left-handedness. In the development of neglect in all patients was associated with post-hemorrhagic or post-operative damage to the white matter (the projections of sensory bundles of the parietal and occipital lobes, the periventricular white matter) or the thalamus and corpus callosum. In hemispheric lesions, neglect developed on the background of the corresponding derangements (hemihypesthesia hemianopsia) and were of the same modality. In cases of damage to the corpus callosum, neglect could develop without accompanying sensory disturbances or the phenomenon could occur on different sides (in cases of simultaneous left hemisphere damage). This supports the independent nature of the neglect phenomenon.
Assuntos
Encéfalo/patologia , Malformações Arteriovenosas Intracranianas/psicologia , Transtornos da Percepção/psicologia , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/patologia , Hemorragia Cerebral/patologia , Hemorragia Cerebral/psicologia , Circulação Cerebrovascular/fisiologia , Corpo Caloso/irrigação sanguínea , Corpo Caloso/patologia , Lateralidade Funcional/fisiologia , Giro do Cíngulo/irrigação sanguínea , Giro do Cíngulo/patologia , Hipocampo/irrigação sanguínea , Hipocampo/patologia , Humanos , Malformações Arteriovenosas Intracranianas/etiologia , Malformações Arteriovenosas Intracranianas/patologia , Transtornos da Memória/etiologia , Transtornos da Memória/psicologia , Testes Neuropsicológicos , Transtornos da Percepção/etiologia , Transtornos da Percepção/patologia , Tálamo/irrigação sanguínea , Tálamo/patologiaRESUMO
The authors studied the differences between heat-shock/stress protein 70 (hsp70) gene expression and protein synthesis in the unilateral middle cerebral artery (MCA) microsurgical direct occlusion (Tamura's) model and the unilateral intraluminal occlusion model. In Tamura's model, expression of hsp70 mRNA and HSP70 protein and decreased protein synthesis were detected in the ischemic areas, including the ipsilateral cortex and caudate. These phenomena, however, were not observed in the areas outside the MCA territory, including the ipsilateral thalamus, hippocampus, and substantia nigra. These results were consistent among the experimental rats. In the intraluminal occlusion model, however, induction of both hsp70 mRNA and HSP70 protein and impairment of protein synthesis were noted in the areas outside the MCA territory, including the ipsilateral thalamus, hypothalamus, hippocampus, and substantia nigra, as well as in the MCA territory, including the ipsilateral cortex and caudate. These results were not consistent among the experimental rats. These different results might be due to widespread damage resulting from internal carotid artery (ICA) occlusion in the intraluminal occlusion model. Accordingly, the authors suggest that this model be called an ICA occlusion model, rather than a pure MCA occlusion model.
Assuntos
Coagulação Sanguínea/fisiologia , Ataque Isquêmico Transitório/patologia , Artéria Cerebral Média/fisiopatologia , Animais , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/metabolismo , Núcleo Caudado/patologia , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP70/genética , Imuno-Histoquímica , Ataque Isquêmico Transitório/genética , Artéria Cerebral Média/patologia , RNA Mensageiro/genética , Ratos , Substância Negra/irrigação sanguínea , Substância Negra/metabolismo , Substância Negra/patologia , Tálamo/irrigação sanguínea , Tálamo/metabolismo , Tálamo/patologia , Fatores de TempoRESUMO
Comparative studies have implicated the nucleus accumbens (NAcc) in the anticipation of incentives, but the relative responsiveness of this neural substrate during anticipation of rewards versus punishments remains unclear. Using event-related functional magnetic resonance imaging, we investigated whether the anticipation of increasing monetary rewards and punishments would increase NAcc blood oxygen level-dependent contrast (hereafter, "activation") in eight healthy volunteers. Whereas anticipation of increasing rewards elicited both increasing self-reported happiness and NAcc activation, anticipation of increasing punishment elicited neither. However, anticipation of both rewards and punishments activated a different striatal region (the medial caudate). At the highest reward level ($5.00), NAcc activation was correlated with individual differences in self-reported happiness elicited by the reward cues. These findings suggest that whereas other striatal areas may code for expected incentive magnitude, a region in the NAcc codes for expected positive incentive value.
Assuntos
Intuição/fisiologia , Núcleo Accumbens/fisiologia , Recompensa , Adulto , Mapeamento Encefálico , Núcleo Caudado/anatomia & histologia , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/fisiologia , Sinais (Psicologia) , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Núcleo Accumbens/anatomia & histologia , Núcleo Accumbens/irrigação sanguínea , Oxigênio/sangue , Tálamo/anatomia & histologia , Tálamo/irrigação sanguínea , Tálamo/fisiologiaRESUMO
Functional brain mapping based on changes in local cerebral blood flow (lCBF) or glucose utilization (lCMR(glc)) induced by functional activation is generally carried out in animals under anesthesia, usually alpha-chloralose because of its lesser effects on cardiovascular, respiratory, and reflex functions. Results of studies on the role of nitric oxide (NO) in the mechanism of functional activation of lCBF have differed in unanesthetized and anesthetized animals. NO synthase inhibition markedly attenuates or eliminates the lCBF responses in anesthetized animals but not in unanesthetized animals. The present study examines in conscious rats and rats anesthetized with alpha-chloralose the effects of vibrissal stimulation on lCMR(glc) and lCBF in the whisker-to-barrel cortex pathway and on the effects of NO synthase inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) on the magnitude of the responses. Anesthesia markedly reduced the lCBF and lCMR(glc) responses in the ventral posteromedial thalamic nucleus and barrel cortex but not in the spinal and principal trigeminal nuclei. L-NAME did not alter the lCBF responses in any of the structures of the pathway in the unanesthetized rats and also not in the trigeminal nuclei of the anesthetized rats. In the thalamus and sensory cortex of the anesthetized rats, where the lCBF responses to stimulation had already been drastically diminished by the anesthesia, L-NAME treatment resulted in loss of statistically significant activation of lCBF by vibrissal stimulation. These results indicate that NO does not mediate functional activation of lCBF under physiological conditions.