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1.
Neurol Sci ; 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39212793

RESUMO

BACKGROUND: Cognitive impairment is one of the most common symptoms of Parkinson's disease (PD), and may be detectable through changes in neural features visualized by magnetic resonance imaging (MRI). Mild cognitive impairment is a transitional state between normal aging and dementia, and early recognition of Parkinson's disease with mild cognitive impairment (PD-MCI) can help improve the quality of life and treatment for patients. This study investigated the association of enlarged perivascular space (EPVS) and white matter hyperintensity (WMH) with PD-MCI. AIMS: This study aimed to evaluate whether EPVS and WMH can be used as potential MRI markers for PD-MCI. METHODS: This retrospective study involved 200 patients with PD who underwent cranial MRI in our hospital from April 2021 to April 2022. Patients were divided into those with no cognitive impairment (PD-NCI) or mild cognitive impairment. Uni- and multivariate logistic regression analyzed associations of EPVS, WMH, and clinicodemographic characteristics with cognitive decline. RESULTS: Univariate regression identified severe EPVS in basal ganglia, severe WMH, older age, late-onset, male sex, low educational level, longer duration of disease, low triglycerides, low uric acid, and low scores on the Mini-mental State Exam as risk factors for PD-MCI. After adjusting for clinicodemographic risk factors in multivariate regression, low education level and EPVS in basal ganglia remained risk factors for cognitive impairment. CONCLUSIONS: Severe EPVS in basal ganglia and poor education, but not WMH, are independent risk factors of PD-MCI. Our findings suggest that non-invasive detection of EPVS in basal ganglia by MRI may be a valuable early indicator of cognitive decline in PD patients.

2.
Int J Neurosci ; : 1-6, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38085250

RESUMO

BACKGROUND: Parkinson's disease is the second most common neurodegenerative disorder with complex and distributed motor and non-motor symptoms. In this study, cortical gray matter (GM) and cerebral white matter (WM) overall atrophy, and asymmetry of atrophy are investigated in PD with normal cognitive function. METHOD: Forty-eight male Parkinson's disease(PD) patients with normal cognitive precede (PD-NC), and thirty matched healthy control (HC) subjects were selected from the Parkinson's Progression Markers Initiative (PPMI) database. Brain structures volumes were extracted using Freesurfer software based on subject 3 tesla MRI images. The normalized volume of cortical GM and cerebral WM were compared in two study groups, and then the asymmetry index (AI) of GM and WM atrophy was also assessed in two groups. Statistical analysis was constructed using a t-test with p < 0.05 of significance. RESULTS: No significant difference was observed in the volume of cortical GM and cerebral WM in the two study groups. The cortical GM asymmetry index in the PD-NC group was significantly (p = 0.01) higher than the HC group, however, no difference was observed for the cerebral WM asymmetry index. CONCLUSION: Atrophy in cortical GM and WM was not observed between the PD-NC and the HC group, however, the asymmetry index in GM was significant between the two group. It seems that the brain's bilateral balance has ruptured in PD. Cortical GM asymmetry in PD-NC can be considered a potent biomarker and should be investigated more in the future. In future studies, construction of a longitudinal study on this issue could be useful.

3.
Neurobiol Dis ; 174: 105862, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36113749

RESUMO

Krabbe Disease (KD) is an autosomal recessive disorder that results from loss-of-function mutations in the GALC gene, which encodes lysosomal enzyme galactosylceramidase (GALC). Functional deficiency of GALC is toxic to myelin-producing cells, which leads to progressive demyelination in both the central and peripheral nervous systems. It is hypothesized that accumulation of psychosine, which can only be degraded by GALC, is a primary initiator of pathologic cascades. Despite the central role of GALC in KD pathomechanism, investigations of GALC deficiency at a protein level are largely absent, due in part, to the lack of sensitive antibodies in the field. Leveraging two custom antibodies that can detect GALC at endogenous levels, we demonstrated that GALC protein is predominantly localized to oligodendrocytes in cerebral white matter of an infant brain, consistent with its functional role in myelination. Mature GALC could also be quantitatively detected as a 26 kDa band by western blotting and correlated to enzyme activity in brain tissues. The p.Ile562Thr polymorphic variant, which is over-represented in the KD population, was associated with reduced mature GALC protein and activity. In three infantile KD cases, homozygous null mutations in GALC lead to deficiency in total GALC protein and activity. Interestingly, although GALC activity was absent, normal levels of total GALC protein were detected by a sandwich ELISA using our custom antibodies in a later-onset KD brain, which suggests that the assay has the potential to differentiate infantile- and later-onset KD cases. Among the infantile KD cases, we quantified a 5-fold increase in psychosine levels, and observed increased levels of acid ceramidase, a key enzyme for psychosine production, and hyperglycosylated lysosomal-associated membrane protein 1, a marker for lysosomal activation, in periventricular white matter, a major pathological brain region, when compared with age-matched normal controls. While near complete demyelination was observed in these cases, we quantified that an early-infantile case (age of death at 10 months) had about 3-fold increases in both globoid cells, a pathological hallmark for KD, and CD8-positive T lymphocytes, a pathological marker for multiple sclerosis, in the white matter when compared with a slower progressing infantile case (age of death at 21 months), which suggests a positive correlation between clinical severity and neuropathology. Taken together, our findings have advanced the understanding of GALC protein biology in the context of normal and KD brain white matter. We also revealed new neuropathological changes that may provide insights to understand KD pathogenesis.


Assuntos
Leucodistrofia de Células Globoides , Substância Branca , Humanos , Galactosilceramidase/genética , Galactosilceramidase/metabolismo , Leucodistrofia de Células Globoides/genética , Leucodistrofia de Células Globoides/patologia , Psicosina/metabolismo , Substância Branca/patologia , Mutação
4.
J Anat ; 241(3): 789-808, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35638263

RESUMO

Although the term sulcus is known for almost four centuries, its formal, precise, consistent, constructive, and quantitative definition is practically lacking. As the cerebral sulci (and gyri) are vital in cortical anatomy which, in turn, is central in neuroeducation and neuroimage processing, a new sulcus definition is needed. The contribution of this work is threefold, namely to (1) propose a new, morphology-based definition of the term sulcus (and consequently that of gyrus), (2) formulate a constructive method for sulcus calculation, and (3) provide a novel way for the presentation of sulci. The sulcus is defined here as a volumetric region on the cortical mantle between adjacent gyri separated from them at the levels of their gyral white matter crest lines. Consequently, the sulcal inner surface is demarcated by the crest lines of the gyral white matter of its adjacent gyri. Correspondingly, the gyrus is defined as a volumetric region on the cortical mantle separated from its adjacent sulci at the level of its gyral white matter crest line. This volumetric sulcus definition is conceptually simple, anatomy-based, educationally friendly, quantitative, and constructive. Considering the sulcus as a volumetric object is a major differentiation from other works. Based on the introduced sulcus definition, a method for volumetric sulcus construction is proposed in two, conceptually straightforward, steps, namely, sulcal intersection formation followed by its propagation which steps are to be repeated for every sulcal segment. These sulcal and gyral constructions can be automated by applying existing methods and public tools. As a volumetric sulcus forms an imprint into the white matter, this enables prominent sulcus presentation. Since this type of presentation is novel yet unfamiliar to the reader, also a dual surface presentation was proposed here by employing the spatially co-registered white matter and cortical surfaces. The results were presented as dual surface labeled sulci on eight standard orthogonal views, anterior, left lateral, posterior, right lateral, superior, inferior, medial left, and medial right by using a 3D brain atlas. Moreover, additional 108 labeled images were created with sulcus-oriented views for 27 individual left and right sulci forming 54 dual white matter-cortical surface images strengthening in this way the educational value of the proposed approach. These images were included for public use in the NOWinBRAIN neuroimage repository with over 7700 3D images available at www.nowinbrain.org. The results demonstrated the superiority of white matter surface sulci presentation over the standard cortical surface and cross-sectional presentations in terms of sulcal course, continuity, size, shape, width, depth, side branches, and pattern. To my best knowledge, this is the first work ever presenting the labeling of sulci on all cerebral white matter surfaces as well as on dual white matter-cortical surfaces. Additionally to neuroeducation, three other applications of the proposed approach were discussed, sulcal reference maps, sulcus quantification in terms of new parameters introduced here (sulcal volume, wall skewness, and the number of white matter basins), and an atlas-assisted tool for exploration and studying of cerebral sulci and gyri .


Assuntos
Cérebro/anatomia & histologia , Substância Branca/anatomia & histologia , Encéfalo/anatomia & histologia , Córtex Cerebral/anatomia & histologia , Estudos Transversais , Humanos , Imageamento por Ressonância Magnética , Substância Branca/diagnóstico por imagem
5.
J Asthma ; 59(2): 288-296, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33263457

RESUMO

OBJECTIVE: Depression is a common co-morbidity in asthma, worsening asthma control and impairing quality of life. Previous studies have reported a higher risk of cognitive deficit in depression, yet little research has focused on the level of cognition in asthmatic patients with depression. Evidence shows that inflammation may play an important role in both asthma and depression. Cerebral white matter injury, possibly induced by inflammation, has been associated with depression. This study assesses cognitive function in patients with asthma and a depression comorbidity, compared to patients with asthma only or depression only. METHODS: Four groups were studied: Asthma comorbid Depression group (A + D, n = 26), Depression group (D, n = 25), Asthma group (A, n = 33) and Normal controls (N, n = 28). Cognitive function was evaluated using Montreal Cognitive Assessment (MoCA). Inflammatory cytokines were measured, including interleukin-1ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), high-mobility group box 1(HMGB1) and Netrin-1. Cerebral white matter injury was assessed by serum myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG), and their correlations with cognitive performance were calculated. RESULTS: A + D group showed the highest incidence of cognitive deficit, with the cognitive domain particularly affected. Compared to N group, serum levels of IL-6, HMGB1, Netrin-1, MBP and MOG were significantly elevated in A + D group. MOG level negatively correlated with the MoCA score. CONCLUSION: Patients with comorbidities presented with more severe cognitive deficits and higher levels of inflammatory cytokines. Cerebral white matter injury may account for the cognitive deficit in patients and MOG could be a potential biomarker for this process.


Assuntos
Asma , Proteína HMGB1 , Substância Branca , Asma/complicações , Asma/epidemiologia , Cognição , Citocinas/metabolismo , Depressão/complicações , Depressão/epidemiologia , Proteína HMGB1/metabolismo , Humanos , Inflamação , Interleucina-6 , Netrina-1/metabolismo , Qualidade de Vida , Substância Branca/diagnóstico por imagem , Substância Branca/metabolismo
6.
Psychol Med ; : 1-10, 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33849668

RESUMO

BACKGROUND: Cynical hostility (CH), a specific dimension of hostility that consists of a mistrust of others, has been suggested as a high-risk trait for dementia. However, the influence of CH on the incidence of Alzheimer's disease (AD) remains poorly understood. This study investigated whether late-life CH is associated with AD risk and structural neuroimaging markers of AD. METHODS: In community-dwelling older adults from the French ESPRIT cohort (n = 1388), incident dementia rate according to CH level was monitored during an 8-year follow-up and analyzed using Cox proportional hazards regression models. Brain magnetic resonance imaging volumes were measured at baseline (n = 508). Using automated segmentation procedures (Freesurfer 6.0), the authors assessed brain grey and white volumes on all magnetic resonance imaging scans. They also measured white matter hyperintensities volumes using semi-automated procedures. Mean volumes according to the level of CH were compared using ANOVA. RESULTS: Eighty-four participants developed dementia (32 with AD). After controlling for potential confounders, high CH was predictive of AD (HR 2.74; 95% CI 1.10-6.85; p = 0.030) and all dementia types are taken together (HR 2.30; 95% CI 1.10-4.80; p = 0.027). High CH was associated with white matter alterations, particularly smaller anterior corpus callosum volume (p < 0.01) after False Discovery Rate correction, but not with grey matter volumes. CONCLUSIONS: High CH in late life is associated with cerebral white matter alterations, designated as early markers of dementia, and higher AD risk. Identifying lifestyle and biological determinants related to CH could provide clues on AD physiopathology and avenues for prevention strategies.

7.
Acta Psychiatr Scand ; 144(5): 448-463, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34333760

RESUMO

OBJECTIVE: Psychosis spectrum disorders are associated with cerebral changes, but the prognostic value and clinical utility of these findings are unclear. Here, we applied a multivariate statistical model to examine the predictive accuracy of global white matter fractional anisotropy (FA) for transition to psychosis in individuals at ultra-high risk for psychosis (UHR). METHODS: 110 UHR individuals underwent 3 Tesla diffusion-weighted imaging and clinical assessments at baseline, and after 6 and 12 months. Using logistic regression, we examined the reliability of global FA at baseline as a predictor for psychosis transition after 12 months. We tested the predictive accuracy, sensitivity and specificity of global FA in a multivariate prediction model accounting for potential confounders to FA (head motion in scanner, age, gender, antipsychotic medication, parental socioeconomic status and activity level). In secondary analyses, we tested FA as a predictor of clinical symptoms and functional level using multivariate linear regression. RESULTS: Ten UHR individuals had transitioned to psychosis after 12 months (9%). The model reliably predicted transition at 12 months (χ2  = 17.595, p = 0.040), accounted for 15-33% of the variance in transition outcome with a sensitivity of 0.70, a specificity of 0.88 and AUC of 0.87. Global FA predicted level of UHR symptoms (R2  = 0.055, F = 6.084, p = 0.016) and functional level (R2  = 0.040, F = 4.57, p = 0.036) at 6 months, but not at 12 months. CONCLUSION: Global FA provided prognostic information on clinical outcome and symptom course of UHR individuals. Our findings suggest that the application of prediction models including neuroimaging data can inform clinical management on risk for psychosis transition.


Assuntos
Transtornos Psicóticos , Substância Branca , Anisotropia , Imagem de Difusão por Ressonância Magnética , Humanos , Escalas de Graduação Psiquiátrica , Transtornos Psicóticos/diagnóstico por imagem , Reprodutibilidade dos Testes , Fatores de Risco , Substância Branca/diagnóstico por imagem
8.
Eur J Neurosci ; 50(10): 3578-3589, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31278790

RESUMO

The question whether body height is related to different brain size measures has recently gained renewed interest as some studies have reported that body height correlates with intelligence and several brain size measures. In this study, we re-evaluated this question by examining the relationship between body height and different brain size measures including intracranial volume, total brain volume, total cortical surface area, total cortical volume, volume of normal-appearing white matter, white matter hyperintensity, cortical surface area, cortical thickness, subcortical grey matter volume, cerebellar cortex and cerebellar white matter in a relatively large sample (n = 216) of physically and cognitively healthy elderly subjects (mean age 71 years, age range 65-85 years). We identified small correlations (r = .11-.19) between body height and seven out of 10 brain metrics (total brain volume, cortical surface area, cortical volume, subcortical volume, normal-appearing white matter volume and cerebellar grey as well as white matter volumes) when controlling for sex and age. Based on these small relationships between body height and various brain size measures, we discuss the possible reasons and theoretical problems for these small relationships.


Assuntos
Envelhecimento/fisiologia , Estatura , Encéfalo/crescimento & desenvolvimento , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Tamanho do Órgão
9.
Cardiol Young ; 29(8): 1107-1109, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31288876

RESUMO

A right aortic arch with an isolated left innominate artery is a rare form of aortic arch anomaly. We present a case of neonatal diagnosis of this anomaly with concerning findings of global cerebral white matter atrophy at 13 months of age.


Assuntos
Aorta Torácica/anormalidades , Tronco Braquiocefálico/anormalidades , Substância Branca/patologia , Aorta Torácica/diagnóstico por imagem , Atrofia , Tronco Braquiocefálico/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Lactente , Recém-Nascido , Substância Branca/diagnóstico por imagem
10.
Eur J Neurol ; 25(3): 602-605, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29284203

RESUMO

BACKGROUND AND PURPOSE: Juvenile- or adult-onset forms of severe 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency manifesting as complicated hereditary spastic paraplegia have rarely been described. METHODS: Two siblings with mental retardation developed a progressive spastic paraparesis in their late teens. Their diagnostic assessment included extensive neurophysiologic, neuroimaging and metabolic studies. RESULTS: Brain magnetic resonance imaging showed occipital white matter alterations, and electromyography documented a mixed polyneuropathy. Severe hyperhomocisteinemia (>150 µmol/L) associated with the characteristic amino acid profile suggested a diagnosis of severe MTHFR deficiency, confirmed by MTHFR direct sequencing. Treatment with betaine and vitamins benefitted patients' symptoms and diagnostic features. CONCLUSIONS: Severe MTHFR deficiency can be a rare, treatable cause of autosomal recessive complicated hereditary spastic paraplegia. Its screening should be part of the diagnostic flowchart for these disorders.


Assuntos
Homocistinúria/diagnóstico , Deficiência Intelectual/diagnóstico , Metilenotetra-Hidrofolato Redutase (NADPH2)/deficiência , Espasticidade Muscular/diagnóstico , Paraplegia Espástica Hereditária/diagnóstico , Adulto , Feminino , Humanos , Masculino , Transtornos Psicóticos/diagnóstico , Irmãos , Adulto Jovem
11.
Endocr J ; 65(6): 669-675, 2018 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-29643322

RESUMO

Metabolically healthy obese (MHO) individual is known to be defended from the metabolic complications of obesity. Leukoaraiosis, which is commonly detected on brain magnetic resonance imaging (MRI), is now recognized as a risk of stroke, dementia and death. However, the association between MHO and the prevalence of leukoaraiosis is unclear. In this cross-sectional study of 796 participants who received a medical examination program, we investigated the association between MHO and the prevalence of leukoaraiosis. We used common clinical markers for definition of metabolic healthy status: blood pressure, fasting plasma glucose, triglycerides and high-density lipoprotein cholesterol concentrations. Obesity was defined by body mass index ≥25.0 kg/m2. We diagnosed leukoaraiosis by fluid-attenuated inversion recovery without hypointensity on T1-weighted images or the presence of a hyperintensity on T2-weighted images. The crude prevalence proportion of leukoaraiosis was 44.5% (case/n = 171/384) in metabolically healthy nonobese (MHNO) individual, 46.3% (44/95) in MHO individual, 62.3% (114/183) in metabolically unhealthy nonobese (MUNO) individual or 56.6% (77/136) in MUO individual. The odds ratios of prevalence of leukoaraiosis were 1.19 (95% CI 0.74-1.90, p = 0.471) for MHO, 1.79 (1.22-2.62, p = 0.003) for MUNO and 1.56 (1.03-2.37, p = 0.037) for MUO individuals after adjusting for sex, age, smoking statues, habit of exercise and alcohol, compared with MHNO individual. We revealed that MHO individuals were not related with the higher risk of leukoaraiosis, whereas MUNO and MUO individuals were.


Assuntos
Leucoaraiose/etiologia , Obesidade Metabolicamente Benigna/complicações , Fatores Etários , Idoso , Glicemia , Índice de Massa Corporal , Encéfalo/diagnóstico por imagem , Estudos Transversais , Feminino , Humanos , Leucoaraiose/sangue , Leucoaraiose/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Obesidade Metabolicamente Benigna/sangue , Obesidade Metabolicamente Benigna/diagnóstico por imagem , Fatores de Risco , Fatores Sexuais , Triglicerídeos/sangue
12.
Metab Brain Dis ; 33(4): 1385-1388, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29752657

RESUMO

Adiponectin is an adipocyte-derived peptide that increases with age and is thought to protect against atherosclerotic vascular changes and organ damage. However, paradoxically, higher adiponectin levels are associated with increased risk for cardiovascular events and mortality. We investigated whether this adiponectin paradox occurs in elderly people with cognitive impairment. Fifty-two elderly participants with mild cognitive impairment or dementia (20 male and 32 female, aged 60-93 years, mean 80.0) were recruited. We evaluated serum adiponectin levels and cerebral white matter lesions (WML), which are involved in cognitive decline and dementia, by computed tomography. Body mass index (BMI), Mini-Mental State Examination score, history of hypertension (HT), chronic kidney disease, and diabetes mellitus were also assessed. Stepwise multiple regression analysis was used to reveal the relationships between serum adiponectin and age, sex, BMI, HT, diabetes mellitus, chronic kidney disease, Mini-Mental State Examination, and WML scores. High serum adiponectin levels correlated with more severe WML (P = 0.013). Low BMI (P < 0.001), female sex (P = 0.025), and high WML scores (P = 0.039) were significant determinants of high serum adiponectin. HT (P = 0.032) and high adiponectin levels (P = 0.021) were independent risk factors for WML. Overall, we observed an association between serum adiponectin levels and WML severity in elderly people with cognitive decline. Our findings reveal that the adiponectin paradox occurs in this population, and this study may help guide future treatments for elderly people with mild cognitive impairment or dementia.


Assuntos
Adiponectina/sangue , Disfunção Cognitiva/sangue , Disfunção Cognitiva/patologia , Substância Branca/patologia , Idoso , Idoso de 80 Anos ou mais , Instituições de Assistência Ambulatorial , Biomarcadores/sangue , Demência/sangue , Demência/patologia , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Fatores de Risco , Fatores Sexuais , Estatísticas não Paramétricas , Tomógrafos Computadorizados
13.
Pol J Radiol ; 83: e76-e81, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30038682

RESUMO

Leukoaraiosis is a pathological appearance of the brain white matter, which has long been believed to be caused by perfusion disturbances within the arterioles perforating through the deep brain structures. Due to its complex etiopathogenesis and clinical relevance, leukoaroisosis has been investigated in a multitude of studies. As regards the clinical implications of leukoaraiosis, this neuroimaging finding is strongly related to ischaemic stroke, unfavourable course of ischaemic stroke in the acute phase, worse long-term outcomes, and cognitive disturbances. The morphological changes in the deep white matter that are collectively described as leukoaraiosis, despite a seemingly homogenous appearance, probably resulting from various causes, such as atherosclerosis, neurotoxic factors including radiation therapy and chemotherapy, and neuroinfections. Based on our experience and recent literature, we present the symptomatology of leukoaroisosis and similar radiological abnormalities of the cerebral white matter.

14.
AJR Am J Roentgenol ; 209(3): W160-W168, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28678575

RESUMO

OBJECTIVE: The purposes of this article are to describe the important role of the medullary arteries in the pathogenesis of cerebral vascular disease and to present a classification of MRI findings of ischemic white matter lesions for use in elucidating pathogenesis. CONCLUSION: From the viewpoint of the anatomy of the medullary arteries, the pattern of medullary artery-related ischemic changes and infarcts can be classified into four types: 1, ischemic leukoaraiosis; 2, infarcts involving individual medullary arteries; 3, watershed infarcts; and 4, territorial infarcts.


Assuntos
Isquemia Encefálica/patologia , Artérias Cerebrais/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Substância Branca/patologia , Pontos de Referência Anatômicos , Humanos
16.
Neuroimage ; 114: 136-46, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-25862261

RESUMO

Quantification of magnetization-transfer (MT) experiments is typically based on a model comprising a liquid pool "a" of free water and a semisolid pool "b" of motionally restricted macromolecules or membrane compounds. By a comprehensive fitting approach, high quality MT parameter maps of the human brain are obtained. In particular, a distinct correlation between the diffusion-tensor orientation with respect to the B0-magnetic field and the apparent transverse relaxation time, T2(b), of the semisolid pool (i.e., the width of its absorption line) is observed. This orientation dependence is quantitatively explained by a refined dipolar lineshape for pool b that explicitly considers the specific geometrical arrangement of lipid bilayers wrapped around a cylindrical axon. The model inherently reduces the myelin membrane to its lipid constituents, which is motivated by previous studies on efficient interaction sites (e.g., cholesterol or galactocerebrosides) in the myelin membrane and on the origin of ultrashort T2 signals in cerebral white matter. The agreement between MT orientation effects and corresponding forward simulations using empirical diffusion imaging results as input as well as results from fits employing the novel lineshape support previous suggestions that the fiber orientation distribution in a voxel can be modeled as a scaled Bingham distribution.


Assuntos
Química Encefálica , Campos Magnéticos , Bainha de Mielina/química , Substância Branca/química , Adulto , Simulação por Computador , Difusão , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Feminino , Humanos , Masculino , Modelos Neurológicos , Adulto Jovem
17.
Intern Med J ; 45(4): 390-5, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25644475

RESUMO

BACKGROUND/AIM: Cerebral white matter changes (WMC) are commonly observed in magnetic resonance imaging (MRI) scans of elderly people. Information about the prevalence of WMC is limited, and little is known about site-specific risk factors for the subcortical and periventricular regions in patients with ischaemic stroke. The study aims to analyse the prevalence and severity of WMC and investigate the risk factors of periventricular WMC (PVWMC) and deep WMC (DWMC) separately in patients with ischaemic stroke. METHODS: The data were collected between January and December 2013 from a medical centre in southern Taiwan. Every patient underwent a cerebral MRI scan, and WMC was separately rated as PVWMC and DWMC by using the modified Fazekas scale. RESULTS: In total, 527 patients who had experienced ischaemic stroke were included. The mean age of the patients was 67.0 ± 12.5 years (range: 31-94) and 62% of them were men. The mean age was significantly different among the four grades of severity in both the PVWMC (P < 0.001) and DWMC (P < 0.001) groups after adjustments for sex and vascular risk factors. Hypertension was independently correlated with severity of DWMC (P = 0.032) but not with PVWMC (P = 0.222). In multiple logistic regressions model, hypertension was a significant independent indicator of DWMC (odds ratio = 4.30; 95% confidence interval = 1.70-10.89). CONCLUSION: Our results suggest a region-specific pathogenesis of cerebral white matter in Asian patients with ischaemic stroke that may differ from those in the general population.


Assuntos
Isquemia Encefálica/diagnóstico , Leucoaraiose/diagnóstico , Acidente Vascular Cerebral/diagnóstico , Substância Branca/patologia , Adulto , Idoso , Isquemia Encefálica/epidemiologia , Isquemia Encefálica/metabolismo , Feminino , Humanos , Leucoaraiose/epidemiologia , Leucoaraiose/metabolismo , Imageamento por Ressonância Magnética/tendências , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/metabolismo , Taiwan/epidemiologia , Substância Branca/metabolismo
18.
Vet Radiol Ultrasound ; 56(2): 188-95, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25288360

RESUMO

Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three-dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1- and T2-weighted images and DTI were acquired at different planes. Using DTT, three-dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto-occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI.


Assuntos
Imagem de Tensor de Difusão/veterinária , Cães/anatomia & histologia , Substância Branca/anatomia & histologia , Animais , Anisotropia , Ventrículos Cerebrais/anatomia & histologia , Corpo Caloso/anatomia & histologia , Difusão , Estudos de Viabilidade , Lobo Frontal/anatomia & histologia , Giro do Cíngulo/anatomia & histologia , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/veterinária , Imageamento por Ressonância Magnética/veterinária , Lobo Occipital/anatomia & histologia , Tratos Piramidais/anatomia & histologia , Lobo Temporal/anatomia & histologia
19.
Am J Obstet Gynecol ; 211(3): 257.e1-5, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24593937

RESUMO

OBJECTIVE: Women who suffered eclampsia or preterm preeclampsia are twice as likely to demonstrate cerebral white matter lesions (WML) on magnetic resonance imaging compared with age-matched women who had normotensive pregnancies, and they report more cognitive dysfunctions in everyday life. We aimed to determine whether pregnancy in and of itself has a relationship with the presence of WML and subjective cognitive dysfunction. STUDY DESIGN: Eighty-one parous women who had a normotensive pregnancy were matched for age with 65 nulliparous women and all underwent cerebral magnetic resonance imaging. Presence of cerebral WML was rated and blood pressure was measured. Subjective cognitive functioning was assessed using the Cognitive Failures Questionnaire. RESULTS: There was no difference in the presence (22% vs 19%) of WML between parous and nulliparous women. Age was a predictor for the presence of WML, whereas the presence of current hypertension was not. Average score on the Cognitive Failures Questionnaire was not different between both groups, nor related to WML. CONCLUSION: A history of pregnancy in and of itself is not related to the presence of cerebral WML and the perception of cognitive dysfunction. Because of the relationship with preterm preeclampsia and eclampsia, future research should focus on the clinical importance and development throughout the years of such cerebral WML in young women and focus on risk factors for cardiovascular disease.


Assuntos
Encéfalo/patologia , Transtornos Cognitivos/patologia , Adulto , Fatores Etários , Feminino , Humanos , Hipertensão/complicações , Gravidez , Fatores de Risco
20.
Int J Neurosci ; 124(11): 799-805, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24433122

RESUMO

BACKGROUND: Cerebral white matter hyperdensities (WMH) are frequently reported on brain magnetic resonance images (MRI) of elderly people; its significance is still under debate. METHODS: WMH subtypes may correlate with vascular risk factors, such as aging, hypertension (HTN) and diabetes mellitus (DM). The suggested hypothesis was to find if any of the periventricular WMH (PVWMH) or the deep WMH (DWMH) would be significantly more correlated with the above vascular risk factors. According to the Fazekas semiquantitative rating scale, we classified WMH into four subtypes: (1) absence of WMH, (2) presence of DWML, (3) presence of PVWMH, (4) presence of both DWML and PVWML. The study was performed on 257 Lebanese inpatients aged 40 years and above who underwent a brain MRI, regardless of their underlying pathology and who were admitted to an Internal Medicine Department in Beirut. The study patients were categorized into five subgroups by age intervals of 10 years. RESULTS: Mean age was 62; 54.1% were females; WMH were observed in 59.5% of study population; we found a linear correlation with WMH and aging with a clear shift for patients over age 60, reaching 84% in patients subgroup of 70-79-year-old and 94% patients subgroup over 80-year-old. PVWMH was found significantly more frequently and in linear correlation with aging and HTN. WMH were also found more frequently among the DM individuals. CONCLUSION: From this first ever retrospective Lebanese study, WMH was reported increasingly with aging in accordance with data from the literature; PVWMH was found significantly more correlated with aging and HTN than was DWMH alone.


Assuntos
Envelhecimento/patologia , Diabetes Mellitus/patologia , Hipertensão/patologia , Substância Branca/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Córtex Cerebral/patologia , Feminino , Humanos , Líbano , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Estudos Retrospectivos , Fatores de Risco
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