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1.
Acta Psychiatr Scand ; 140(3): 205-216, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31265120

RESUMO

OBJECTIVE: Several studies have found an increase in hippocampal volume following electroconvulsive therapy (ECT), but the effect on cortical thickness has been less investigated. We aimed to examine the effects of ECT on cortical thickness and their associations with clinical outcome. METHOD: Using 3 Tesla MRI scanner, we obtained T1-weighted brain images of 18 severely depressed patients at three time points: before, right after and 6 months after a series of ECT. The thickness of 68 cortical regions was extracted using Free Surfer, and Linear Mixed Model was used to analyze the longitudinal changes. RESULTS: We found significant increases in cortical thickness of 26 regions right after a series of ECT, mainly within the frontal, temporal and insular cortex. The thickness returned to the baseline values at 6-month follow-up. We detected no significant decreases in cortical thickness. The increase in the thickness of the right lateral orbitofrontal cortex was associated with a greater antidepressant effect, r = 0.75, P = 0.0005. None of the cortical regions showed any associations with cognitive side effects. CONCLUSION: The increases in cortical thickness induced by ECT are transient. Further multimodal MRI studies should examine the neural correlates of these increases and their relationship with the antidepressant effect.


Assuntos
Córtex Cerebral/patologia , Transtorno Depressivo/patologia , Transtorno Depressivo/terapia , Eletroconvulsoterapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Córtex Cerebral/diagnóstico por imagem , Transtorno Depressivo/diagnóstico por imagem , Feminino , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Adulto Jovem
2.
Sleep ; 41(3)2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29309697

RESUMO

Study Objectives: Obstructive sleep apnea (OSA) is associated with increased risk of stroke but the underlying mechanism is poorly understood. We suspect that the normal cerebrovascular response to hypoxia is disturbed in patients with OSA. Methods: Global cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and lactate concentration during hypoxia were measured in patients with OSA and matched controls. Twenty-eight patients (82.1% males, mean age 52.3 ± 10.0 years) with moderate-to-severe OSA assessed by partial polysomnography were examined and compared with 19 controls (73.7% males, mean age 51.8 ± 10.1 years). Patients and controls underwent magnetic resonance imaging (MRI) during 35 min of normoxia followed by 35 min inhaling hypoxic air (10%-12% O2). After 3 months of continuous positive airway pressure (CPAP) treatment, 22 patients were rescanned. Results: During hypoxia, CBF significantly increased with decreasing arterial blood oxygen concentration (4.53 mL (blood)/100 g/min per -1 mmol(O2)/L, p < 0.001) in the control group, but was unchanged (0.89 mL (blood)/100 g/min per -1 mmol(O2)/L, p = 0.289) in the patient group before CPAP treatment. The CBF response to hypoxia was significantly weaker in patients than in controls (p = 0.003). After 3 months of CPAP treatment the CBF response normalized, showing a significant increase during hypoxia (5.15 mL (blood)/100 g/min per -1 mmol(O2)/L, p < 0.001). There was no difference in CMRO2 or cerebral lactate concentration between patients and controls, and no effect of CPAP treatment. Conclusions: Patients with OSA exhibit reduced CBF in response to hypoxia. CPAP treatment normalized these patterns.


Assuntos
Circulação Cerebrovascular/fisiologia , Hipóxia/sangue , Ácido Láctico/sangue , Oxigênio/sangue , Apneia Obstrutiva do Sono/sangue , Adulto , Biomarcadores/sangue , Pressão Positiva Contínua nas Vias Aéreas/métodos , Feminino , Humanos , Hipóxia/diagnóstico por imagem , Hipóxia/fisiopatologia , Masculino , Pessoa de Meia-Idade , Polissonografia/métodos , Apneia Obstrutiva do Sono/diagnóstico por imagem , Apneia Obstrutiva do Sono/fisiopatologia
3.
Eur J Neurol ; 24(9): 1116-1124, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28727225

RESUMO

BACKGROUND AND PURPOSE: The integrity of the blood-brain barrier (BBB) has been questioned in migraine, but BBB permeability has never been investigated during spontaneous migraine attacks. In the present study, BBB permeability during spontaneous attacks of migraine without aura was investigated compared to an interictal state. METHODS: Seventy-four patients suffering from migraine without aura were recruited to participate in this cross-sectional dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) study. The patients were instructed to report at the hospital for DCE-MRI scan during and outside of a spontaneous migraine attack. The primary end-point was a difference in the BBB permeability (ml/100 g/min) between the attack and the headache-free days. The permeability was assessed in five different regions of interest (ROIs) located in the anterior, middle and posterior cerebral area, brain stem, posterior pons and whole brain. The paired samples t test was used to compare Ki (permeability) values between the attack and headache-free days. RESULTS: Nineteen patients completed the study. Median time from onset of migraine attack to scan was 6.5 h (range 4.0-15.5 h). No change in the mean BBB permeability (ml/100 g/min) was found between the attack and the headache-free days in any of the measured ROIs. No relationship between the pain side or intensity and BBB permeability was found in 15 patients with unilateral pain during the examined attack. CONCLUSIONS: It was demonstrated that the BBB permeability during spontaneous migraine attacks without aura was unchanged.


Assuntos
Barreira Hematoencefálica/diagnóstico por imagem , Enxaqueca sem Aura/diagnóstico por imagem , Adulto , Barreira Hematoencefálica/fisiopatologia , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Enxaqueca sem Aura/fisiopatologia , Medição da Dor , Permeabilidade , Cintilografia , Adulto Jovem
4.
Mult Scler ; 21(14): 1761-70, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25698172

RESUMO

BACKGROUND: Cerebrospinal fluid (CSF) biomarkers have been suggested to predict multiple sclerosis (MS) after clinically isolated syndromes, but studies investigating long-term prognosis are needed. OBJECTIVE: To assess the predictive ability of CSF biomarkers with regard to MS development and long-term disability after optic neuritis (ON). METHODS: Eighty-six patients with ON as a first demyelinating event were included retrospectively. Magnetic resonance imaging (MRI), CSF leukocytes, immunoglobulin G index and oligoclonal bands were registered. CSF levels of chitinase-3-like-1, osteopontin, neurofilament light-chain, myelin basic protein, CCL2, CXCL10, CXCL13 and matrix metalloproteinase-9 were measured by enzyme-linked immunosorbent assay. Patients were followed up after 13.6 (range 9.6-19.4) years and 81.4% were examined, including Expanded Disability Status Scale and MS functional composite evaluation. 18.6% were interviewed by phone. Cox regression, multiple regression and Spearman correlation analyses were used. RESULTS: Forty-six (53.5%) developed clinically definite MS (CDMS) during follow-up. In a multivariate model MRI (p=0.0001), chitinase 3-like 1 (p=0.0033) and age (p=0.0194) combined predicted CDMS best. Neurofilament light-chain predicted long-term disability by the multiple sclerosis severity scale (p=0.0111) and nine-hole-peg-test (p=0.0202). Chitinase-3-like-1 predicted long-term cognitive impairment by the paced auditory serial addition test (p=0.0150). CONCLUSION: Neurofilament light-chain and chitinase-3-like-1 were significant predictors of long-term physical and cognitive disability. Furthermore, chitinase-3-like-1 predicted CDMS development. Thus, these molecules hold promise as clinically valuable biomarkers after ON as a first demyelinating event.


Assuntos
Adipocinas/líquido cefalorraquidiano , Progressão da Doença , Lectinas/líquido cefalorraquidiano , Esclerose Múltipla/líquido cefalorraquidiano , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Neurite Óptica/líquido cefalorraquidiano , Adolescente , Adulto , Biomarcadores/líquido cefalorraquidiano , Proteína 1 Semelhante à Quitinase-3 , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Índice de Gravidade de Doença , Adulto Jovem
5.
Mov Disord ; 29(9): 1212-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24867681

RESUMO

BACKGROUND: Imaging studies of patients with Tourette's syndrome (TS) across different cohorts have shown alterations in gray and white matter in areas associated with the cortico-striato-thalamic-cortical (CSTC) pathways; however, no consistent findings have subsequently established a clear indication of the pathophysiology of TS. METHODS: This study was designed to investigate changes in gray and white matter in medication-free children with TS in the CSTC areas. With MRI, 24 children with TS and 18 healthy controls were analyzed using three complementary methods. RESULTS AND CONCLUSION: Analyses revealed no differences between controls and patients with TS in gray or white matter. Possible discrepancies between cohorts and methods may play a role in the different findings in other studies. Further studies investigating well-defined cohorts with TS analyzing both gray and white matter in the same cohort may add additional information to the pathophysiology of TS.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética , Síndrome de Tourette/patologia , Mapeamento Encefálico , Estudos de Casos e Controles , Criança , Corpo Caloso/patologia , Imagem de Tensor de Difusão , Feminino , Humanos , Masculino
6.
Neuroimage Clin ; 4: 182-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24371801

RESUMO

OBJECTIVES: To investigate whether blood-brain barrier (BBB) permeability is disrupted in normal appearing white matter in MS patients, when compared to healthy controls and whether it is correlated with MS clinical characteristics. METHODS: Dynamic contrast-enhanced MRI was used to measure BBB permeability in 27 patients with MS and compared to 24 matched healthy controls. RESULTS: Permeability measured as K(trans) was significantly higher in periventricular normal appearing white matter (NAWM) and thalamic gray matter in MS patients when compared to healthy controls, with periventricular NAWM showing the most pronounced difference. Recent relapse coincided with significantly higher permeability in periventricular NAWM, thalamic gray matter, and MS lesions. Immunomodulatory treatment and recent relapse were significant predictors of permeability in MS lesions and periventricular NAWM. Our results suggest that after an MS relapse permeability gradually decreases, possibly an effect of immunomodulatory treatment. CONCLUSIONS: Our results emphasize the importance of BBB pathology in MS, which we find to be most prominent in the periventricular NAWM, an area prone to development of MS lesions. Both the facts that recent relapse appears to cause widespread BBB disruption and that immunomodulatory treatment seems to attenuate this effect indicate that BBB permeability is intricately linked to the presence of MS relapse activity. This may reveal further insights into the pathophysiology of MS.


Assuntos
Barreira Hematoencefálica/fisiopatologia , Esclerose Múltipla/patologia , Adulto , Permeabilidade Capilar/fisiologia , Meios de Contraste , Feminino , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão , Índice de Gravidade de Doença , Substância Branca/patologia
7.
Am J Physiol Endocrinol Metab ; 305(4): E496-506, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23800880

RESUMO

Physical exercise increases peripheral insulin sensitivity, but regional differences are poorly elucidated in humans. We investigated the effect of aerobic exercise training on insulin-stimulated glucose uptake in five individual femoral muscle groups and four different adipose tissue regions, using dynamic (femoral region) and static (abdominal region) 2-deoxy-2-[¹8F]fluoro-d-glucose (FDG) PET/CT methodology during steady-state insulin infusion (40 mU·m⁻²·min⁻¹). Body composition was measured by dual X-ray absorptiometry and MRI. Sixty-one healthy, sedentary [V(O2max) 36(5) ml·kg⁻¹·min⁻¹; mean(SD)], moderately overweight [BMI 28.1(1.8) kg/m²], young [age: 30(6) yr] men were randomized to sedentary living (CON; n = 17 completers) or moderate (MOD; 300 kcal/day, n = 18) or high (HIGH; 600 kcal/day, n = 18) dose physical exercise for 11 wk. At baseline, insulin-stimulated glucose uptake was highest in femoral skeletal muscle followed by intraperitoneal visceral adipose tissue (VAT), retroperitoneal VAT, abdominal (anterior + posterior) subcutaneous adipose tissue (SAT), and femoral SAT (P < 0.0001 between tissues). Metabolic rate of glucose increased similarly (~30%) in the two exercise groups in femoral skeletal muscle (MOD 24[9, 39] µmol·kg⁻¹·min⁻¹, P = 0.004; HIGH 22[9, 35] µmol·kg⁻¹·min⁻¹, P = 0.003) (mean[95% CI]) and in five individual femoral muscle groups but not in femoral SAT. Standardized uptake value of FDG decreased ~24% in anterior abdominal SAT and ~20% in posterior abdominal SAT compared with CON but not in either intra- or retroperitoneal VAT. Total adipose tissue mass decreased in both exercise groups, and the decrease was distributed equally among subcutaneous and intra-abdominal depots. In conclusion, aerobic exercise training increases insulin-stimulated glucose uptake in skeletal muscle but not in adipose tissue, which demonstrates some interregional differences.


Assuntos
Tecido Adiposo Branco/metabolismo , Exercício Físico , Transportador de Glucose Tipo 4/metabolismo , Glucose/metabolismo , Resistência à Insulina , Músculo Esquelético/metabolismo , Sobrepeso/terapia , Tecido Adiposo Branco/diagnóstico por imagem , Tecido Adiposo Branco/efeitos dos fármacos , Adiposidade , Adulto , Transporte Biológico/efeitos dos fármacos , Índice de Massa Corporal , Meios de Contraste/metabolismo , Fluordesoxiglucose F18/metabolismo , Técnica Clamp de Glucose , Transportador de Glucose Tipo 4/biossíntese , Humanos , Hipoglicemiantes/metabolismo , Hipoglicemiantes/farmacologia , Insulina/metabolismo , Insulina/farmacologia , Estudos Longitudinais , Masculino , Imagem Multimodal , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/efeitos dos fármacos , Sobrepeso/metabolismo , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X , Regulação para Cima , Adulto Jovem
8.
Neurology ; 77(7): 645-51, 2011 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-21813786

RESUMO

OBJECTIVE: We wanted to investigate if retinal nerve fiber layer thickness (RNFLT) measured by optical coherence tomography (OCT) might be a good marker of acute and chronic changes in the afferent visual pathway following acute optic neuritis (ON). METHODS: We studied the relationship of optic nerve lesion length, optic nerve mean area, and RNFLT, quantified by OCT, with fMRI response to a visual paradigm in 40 patients with acute ON and 19 healthy controls in a prospective cohort study over a 6-month period. RESULTS: The main finding was a significant correlation of optic nerve lesion length and mean area with fMRI response in affected eyes in the acute phase and between RNFLT and fMRI response in affected eyes after recovery. CONCLUSION: RNFLT is a very good measure of damage to the afferent visual pathway in recovered patients with ON and should be included in future fMRI studies when looking for visual reorganization in recovered patients with ON.


Assuntos
Atrofia Óptica/patologia , Nervo Óptico/patologia , Neurite Óptica/patologia , Retina/patologia , Adolescente , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Atrofia Óptica/fisiopatologia , Nervo Óptico/fisiopatologia , Neurite Óptica/fisiopatologia , Estudos Prospectivos , Retina/fisiopatologia , Tomografia de Coerência Óptica , Vias Visuais/patologia , Vias Visuais/fisiopatologia
9.
Neurology ; 75(17): 1520-6, 2010 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-20975053

RESUMO

BACKGROUND: Calcitonin gene-related peptide (CGRP) plays a fundamental role in the pathophysiology of neurovascular headaches. CGRP infusion causes headache and dilation of cranial vessels. However, it is unknown to what extent CGRP-induced vasodilation contributes to immediate head pain and whether the migraine-specific abortive drug sumatriptan, a 5-hydroxytryptamine 1B/1D agonist, inhibits CGRP-induced immediate vasodilation and headache. METHODS: We performed a double-blind, randomized, placebo-controlled, crossover study in 18 healthy volunteers. We recorded circumference changes of the middle meningeal artery (MMA) and middle cerebral artery (MCA) using magnetic resonance angiography before and after infusion (20 minutes) of 1.5 µg/min human αCGRP or placebo (isotonic saline) as well as after a 6-mg sumatriptan subcutaneous injection. RESULTS: Compared with placebo, CGRP caused significant dilation of MMA (p = 0.006) and no dilation of MCA (p = 0.69). Sumatriptan caused a marked contraction of MMA (15%-25.2%) and marginal contraction of MCA (3.9% to 5.3%). Explorative analysis revealed that sumatriptan had a more selective action on MMA compared with MCA on the CGRP day (p < 0.0001) and on the placebo day (p = 0.007). CONCLUSION: These data suggest that exogenous CGRP dilates extracranial vessels and not intracranial, and that sumatriptan exerts part of its antinociceptive action by constricting MMA and not MCA. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that IV GCRP causes dilation of the MMA but not the MCA in healthy volunteers, and that sumatriptan reverses the dilation of the MMA caused by CGRP.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Artérias Meníngeas/efeitos dos fármacos , Sumatriptana/farmacologia , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Adulto , Área Sob a Curva , Pressão Sanguínea/efeitos dos fármacos , Peptídeo Relacionado com Gene de Calcitonina/efeitos adversos , Intervalos de Confiança , Método Duplo-Cego , Interações Medicamentosas , Feminino , Cefaleia/induzido quimicamente , Humanos , Angiografia por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Artérias Meníngeas/fisiologia , Artéria Cerebral Média/efeitos dos fármacos , Artéria Cerebral Média/fisiologia , Adulto Jovem
10.
Acta Neurol Scand ; 122(3): 149-58, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20597869

RESUMO

The diagnosis of MS is based on the revised McDonald criteria and is multidisciplinary. Both clinical and paraclinical measures are included. High-field magnetic resonance imaging (MRI) is becoming increasingly available and it is therefore necessary to clarify possible advantages of high-field MRI in MS. The aim of this paper was to review MRI studies in MS where a direct comparison of MRI at high field with MRI at 1-1.5 tesla (T) had been performed. The studies evaluated were found by searching Pubmed with relevant terms including MeSH terms. The reviewed studies all found the conspicuity of lesions to be better at high field. Of the seven studies, six found more and bigger lesions at high-field MRI. In the present paper, the relevant MRI sequences are evaluated in detail. The detection of more lesions at high-field strength did not seem to lead to earlier diagnosis of clinically definite multiple sclerosis. Further larger studies of patients with clinically isolated syndromes are needed to settle the question of a diagnostic consequence of high-field imaging in MS. We suggest that the next revision of the McDonald diagnostic criteria include a recommendation of field strength.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/normas , Esclerose Múltipla/diagnóstico , Diagnóstico Diferencial , Diagnóstico Precoce , Humanos , Processamento de Imagem Assistida por Computador , PubMed/estatística & dados numéricos
11.
Brain ; 128(Pt 11): 2588-96, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16123146

RESUMO

Infants with low birth weight are at increased risk of perinatal brain injury. Disruption of normal cortical development may have consequences for later motor, behavioural and cognitive development. The aim of this study was to measure cerebral cortical thickness, area and volume with an automated MRI technique in 15-year-old adolescents who had low birth weight. Cerebral MRI for morphometric analysis was performed on 50 very low birth weight (VLBW, birth weight

Assuntos
Córtex Cerebral/patologia , Recém-Nascido de Baixo Peso , Adolescente , Peso ao Nascer , Mapeamento Encefálico/métodos , Cefalometria/métodos , Córtex Cerebral/crescimento & desenvolvimento , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Recém-Nascido , Recém-Nascido Pequeno para a Idade Gestacional , Recém-Nascido de muito Baixo Peso , Inteligência , Imageamento por Ressonância Magnética/métodos , Masculino
12.
Med Image Anal ; 9(4): 394-410, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15907391

RESUMO

This paper presents a novel method for registration of single and multi-slice cardiac perfusion MRI. Utilising off-line computer intensive analyses of variance and clustering in an annotated training set, the presented method is capable of providing registration without any manual interaction in less than a second per frame. Changes in image intensity during the bolus passage are modelled by a slice-coupled active appearance model, which is augmented with a cluster analysis of the training set. Landmark correspondences are optimised using the MDL framework due to Davies et al. Image search is verified and stabilised using perfusion specific prior models of pose and shape estimated from training data. Qualitative and quantitative validation of the method is carried out using 2000 clinical quality, short-axis, perfusion MR slice images, acquired from 10 freely breathing patients with acute myocardial infarction. Despite evident perfusion deficits and varying image quality in the limited training set, a leave-one-out cross-validation of the method showed a mean point to curve distance of 1.25+/-0.36 pixels for the left and right ventricle combined. We conclude that this learning-based method holds great promise for the automation of cardiac perfusion investigations, due to its accuracy, robustness and generalisation ability.


Assuntos
Circulação Coronária/fisiologia , Doença das Coronárias/diagnóstico , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Artefatos , Meios de Contraste/farmacocinética , Doença das Coronárias/fisiopatologia , Humanos
13.
Diabet Med ; 21(6): 524-30, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15154934

RESUMO

AIMS: The pathophysiological mechanisms responsible for increased cardiovascular mortality in diabetic autonomic neuropathy (AN) are largely unknown. The aim was to determine the relative role of AN in the pathogenesis of cardiac diastolic dysfunction and left ventricular hypertrophy in Type 1 diabetes. METHODS: Ten Type 1 diabetic patients with AN, defined by cardiovascular tests (AN+) and 10 age- and sex-matched patients without neuropathy (AN-) as well as 10 healthy subjects (C) participated in the study. Left ventricular diastolic function was assessed by Doppler echocardiography, whilst systolic function was evaluated by cine magnetic resonance (MR) imaging. RESULTS: Doppler echocardiography showed a significant decrease in E/A ratio, i.e. the ratio between peak Early transmitral filling velocity during early diastole (E-wave) and peak transmitral Atrial filling velocity during late diastole (A-wave), in AN+ compared with C (P < 0.01) [0.95 +/- 0.08 (mean +/- sem) (AN+); 1.19 +/- 0.09 (AN-); 1.33 +/- 0.10 (C)]. The E-wave deceleration time was significantly shorter in AN+ compared with AN- and C (P < 0.02) [178 +/- 7 ms (AN+); 203 +/- 9 ms (AN-); 205 +/- 9 ms (C)]. Cine MR imaging showed a significantly greater left ventricular mass index in AN+ compared with C [103 +/- 4 g/m(2) (AN+) vs. 98 +/- 7 (AN-) and 92 +/- 4 g/m(2) (C), P < 0.05]. CONCLUSION: Autonomic neuropathy is associated with left ventricular hypertrophy and diastolic dysfunction in Type 1 diabetic patients.


Assuntos
Doenças do Sistema Nervoso Autônomo/complicações , Diabetes Mellitus Tipo 1/complicações , Neuropatias Diabéticas/complicações , Hipertrofia Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/etiologia , Doenças do Sistema Nervoso Autônomo/diagnóstico por imagem , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Pressão Sanguínea/fisiologia , Catecolaminas/sangue , Diabetes Mellitus Tipo 1/diagnóstico por imagem , Diabetes Mellitus Tipo 1/fisiopatologia , Neuropatias Diabéticas/diagnóstico por imagem , Neuropatias Diabéticas/fisiopatologia , Ecocardiografia Doppler/métodos , Feminino , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia
14.
Acta Neurol Scand ; 109(4): 261-9, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15016008

RESUMO

We used post-mortem magnetic resonance imaging (MRI) guidance to obtain paired biopsies from the brains of four patients with clinical definite multiple sclerosis (MS). Samples were analyzed for the immunoreactivity (IR) of the three nitric oxide (NO) synthase isoforms [inducible, neuronal and endothelial nitric oxide synthase (NOS)], and enzymatic NO synthase activity. MRI guided biopsies documented more active plaques than macroscopic examination, and histological examination revealed further lesions. Inducible NOS (iNOS) was the dominant IR isoform, while reactive astrocytes were the dominant iNOS expressing cells in active lesions. NOS IR expressing cells were widely distributed in plaques, in white and gray matter that appeared normal macroscopically, and on MR. Endothelial NOS (eNOS) was highly expressed in intraparenchymal vascular endothelial cells of MS patients. A control group matched for age and sex showed no such changes. Our data support the hypothesis that NO is a pathogenic factor in MS, and that NOS IR is strongly expressed in brain regions appearing normal by MRI.


Assuntos
Encéfalo/enzimologia , Encéfalo/patologia , Esclerose Múltipla/enzimologia , Esclerose Múltipla/patologia , Óxido Nítrico Sintase/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Isoenzimas/metabolismo , Macrófagos/enzimologia , Macrófagos/patologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroglia/enzimologia , Neuroglia/patologia
15.
Mult Scler ; 9(1): 102-7, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12617276

RESUMO

Oral high-dose methylprednisolone treatment is efficacious in acute optic neuritis (ON) and attacks of multiple sclerosis (MS). The responses to treatment in subgroups of patients participating in two randomized, controlled trials were assessed. Fifty-eight patients with ON and 51 patients with attacks of MS were treated with placebo or oral methylprednisolone (500 mg daily for five days with a 10-day tapering period). A gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) scan was obtained at baseline in 66 patients, and 29 patients underwent repeated MRI studies. Seventy-four patients underwent lumbar puncture before treatment. The odds ratio (OR) of improvement after methylprednisolone treatment (a one point change in the visual function system score of the Kurtzke Expanded Disability Status Scale (EDSS) in ON or in the EDSS score in attacks of MS) was higher in patients with enhancing lesions on baseline MRI (one week: OR 15, P = 0.02; eight weeks: OR 4.6, P = 0.02). Methylprednisolone treatment suppressed Gd-enhancement after one week (P < 0.001) and three weeks (P = 0.001). Cerebrospinal fluid measures of intrathecal inflammation correlated with the area of Gd-enhancement but did not correlate as closely with the treatment response as did the results of Gd-enhanced MRI. These findings suggest that the resolution of intrathecal inflammation as assessed by Gd-enhanced MRI is a major effect of oral high-dose methylprednisolone.


Assuntos
Anti-Inflamatórios/administração & dosagem , Imageamento por Ressonância Magnética/métodos , Metilprednisolona/administração & dosagem , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/patologia , Adulto , Barreira Hematoencefálica/efeitos dos fármacos , Feminino , Gadolínio , Humanos , Imunoglobulina A/sangue , Masculino , Esclerose Múltipla/imunologia , Valor Preditivo dos Testes , Resultado do Tratamento
16.
Magn Reson Med ; 48(2): 351-61, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12210944

RESUMO

The quantification of perfusion using dynamic susceptibility contrast MRI (DSC-MRI) requires deconvolution to obtain the residual impulse response function (IRF). In this work, a method using the Gaussian process for deconvolution (GPD) is proposed. The fact that the IRF is smooth is incorporated as a constraint in the method. The GPD method, which automatically estimates the noise level in each voxel, has the advantage that model parameters are optimized automatically. The GPD is compared to singular value decomposition (SVD) using a common threshold for the singular values, and to SVD using a threshold optimized according to the noise level in each voxel. The comparison is carried out using artificial data as well as data from healthy volunteers. It is shown that GPD is comparable to SVD with a variable optimized threshold when determining the maximum of the IRF, which is directly related to the perfusion. GPD provides a better estimate of the entire IRF. As the signal-to-noise ratio (SNR) increases or the time resolution of the measurements increases, GPD is shown to be superior to SVD. This is also found for large distribution volumes.


Assuntos
Circulação Cerebrovascular , Imageamento por Ressonância Magnética/métodos , Meios de Contraste , Gadolínio DTPA , Humanos , Processamento de Imagem Assistida por Computador , Distribuição Normal
17.
Eur J Neurol ; 9(3): 277-86, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-11985636

RESUMO

The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly to both the results of the contrast sensitivity test and to the Snellen visual acuity. Our results indicate that fMRI is a useful method for the study of ON, even in cases where the visual acuity is severely impaired. The reduction in activated volume could be explained as a reduced neuronal input; however, the greater asymmetry might point to a cortical reorganization as a consequence of neuronal damage. Future fMRI studies in ON will add to the understanding of the neural adaptive behaviour following ON.


Assuntos
Imageamento por Ressonância Magnética/métodos , Neurite Óptica/patologia , Neurite Óptica/fisiopatologia , Córtex Visual/patologia , Córtex Visual/fisiologia , Adulto , Sensibilidades de Contraste , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética/normas , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Transtornos da Visão/patologia , Transtornos da Visão/fisiopatologia , Testes Visuais , Visão Binocular , Visão Monocular , Acuidade Visual , Campos Visuais
18.
Magn Reson Imaging ; 20(2): 199-205, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12034341

RESUMO

Sleeping and sedated children can respond to visual stimulation with a decrease in blood oxygenation level dependent (BOLD) functional MRI signal response. The contribution of metabolic and hemodynamic parameters to this inverse signal response is incompletely understood. It has been hypothesized that it is caused by a relatively greater increase of oxygen consumption compared to rCBF (regional cerebral blood flow) increase. We studied the rCBF changes during visual stimulation in four sedated children, aged 4-71 months, and four alert adults, with an arterial water spin labeling technique (FAIR) and BOLD fMRI in a 1.5T MR scanner. In the children, FAIR signal decreased by a mean of 0.96% (range 0.77-1.05) of the baseline periods of the non-selective images, while BOLD signal decreased by 2.03% (range 1.99-2.93). In the adults, FAIR and BOLD signal increased by 0.88% (range 0.8-0.99) and 2.63% (range 1.99-2.93), respectively. Thus, in the children, an rCBF increase could not be detected by perfusion MRI, but indications of a FAIR signal decrease were found. An rCBF decrease in the primary visual cortex during stimulation has not been reported previously, but it is a possible explanation for the negative BOLD response. Future studies will have to address if this response pattern is a consequence of age or sleep/sedation.


Assuntos
Circulação Cerebrovascular , Imageamento por Ressonância Magnética , Estimulação Luminosa , Córtex Visual/fisiologia , Adulto , Criança , Pré-Escolar , Humanos , Hipnóticos e Sedativos , Lactente , Consumo de Oxigênio , Córtex Visual/anatomia & histologia
19.
Stroke ; 33(4): 972-6, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11935046

RESUMO

BACKGROUND AND PURPOSE: There is growing evidence that white matter hyperintensities (WMH) should not be considered as benign age-dependent changes on MR images but indicate pathological changes with clinical consequences. Previous studies comparing subjects with WMH to normal controls have reported global reductions in cerebral blood flow (CBF) and cerebral vascular reactivity. In this study, we examined localized hemodynamic status to compare WMH to normal appearing white matter (NAWM). METHODS: A group of 21 normal 85-year-old subjects were studied using dynamic contrast-enhanced MRI together with administration of acetazolamide. From a combination of anatomic images with different signal weighting, regions of interest were generated corresponding to gray and white matter and WMH. Localized measurements of CBF and cerebral blood volume (CBV) and mean transit time were obtained directly within WMH and NAWM. RESULTS: When comparing WMH to NAWM, measurements showed significantly lower CBF (P=0.004) and longer mean transit time (P< 0.001) in WMH but no significant difference in CBV (P=0.846). The increases in CBF and CBV induced by acetazolamide were significantly smaller in WMH than in NAWM (P=0.026, P<0.001). CONCLUSION: These results show that a change in the hemodynamic status is present within the WMH, making these areas more likely to be exposed to transient ischemia inducing myelin rarefaction. In the future, MRI may be used to examine the effect of therapeutic strategies designed to prevent or normalize vascular changes.


Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Hemodinâmica/fisiologia , Imageamento por Ressonância Magnética/métodos , Acetazolamida/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos de Coortes , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Modelos Cardiovasculares , Valor Preditivo dos Testes , Valores de Referência
20.
Eur J Heart Fail ; 3(6): 699-708, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11738222

RESUMO

BACKGROUND: A range of neurohumoral substances have been suggested as diagnostic markers in heart failure. It is, however, undetermined which marker has the greatest diagnostic potential, and whether additional information is gained by a comprehensive neurohumoral evaluation. AIMS: The purpose of the study was to compare the value of epinephrine, norepinephrine, renin activity, aldosterone (ALDO), atrial (ANP) and brain (BNP) natriuretic peptides, arginine-vasopressin and endothelin (ENDO) as markers for left ventricular (LV) dimensions and ejection fraction (LVEF) in patients with systolic heart failure. METHODS: Forty-eight patients with symptomatic heart failure were examined with blood samples and magnetic resonance imaging along with 20 age and gender-matched normal controls. RESULTS: In multiple regression analyses, BNP was the strongest independent marker for LV end-diastolic (r=0.71, P<0.0001), and end-systolic (r=0.75, P<0.0001) volumes, myocardial mass (r=0.69, P<0.0001), and LVEF (r=-0.78, P<0.0001). ANP was a supplementary independent marker for LV end-diastolic (r=0.76, P<0.0001) and end-systolic (r=0.78, P<0.0001) (ANP and BNP combined) volumes, ENDO for myocardial mass [r=0.71, P<0.0001 (ENDO/BNP)], and ALDO for LVEF [r=-0.81, P<0.0001 (ALDO/BNP)]. CONCLUSION: BNP is the strongest marker for LV dimensions and LVEF in patients with systolic heart failure. However, a comprehensive neurohumoral evaluation may add some information to the diagnosis.


Assuntos
Neurotransmissores/sangue , Volume Sistólico/fisiologia , Disfunção Ventricular Esquerda/sangue , Disfunção Ventricular Esquerda/complicações , Idoso , Aldosterona/sangue , Arginina Vasopressina/sangue , Fator Natriurético Atrial/sangue , Biomarcadores/sangue , Pressão Sanguínea/fisiologia , Endotelina-1/sangue , Epinefrina/sangue , Feminino , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/complicações , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Norepinefrina/sangue , Análise de Regressão , Renina/sangue
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