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Neuroscience Bulletin ; (6): 1533-1543, 2023.
Article in English | WPRIM | ID: wpr-1010620


Alzheimer's disease (AD) is associated with the impairment of white matter (WM) tracts. The current study aimed to verify the utility of WM as the neuroimaging marker of AD with multisite diffusion tensor imaging datasets [321 patients with AD, 265 patients with mild cognitive impairment (MCI), 279 normal controls (NC)], a unified pipeline, and independent site cross-validation. Automated fiber quantification was used to extract diffusion profiles along tracts. Random-effects meta-analyses showed a reproducible degeneration pattern in which fractional anisotropy significantly decreased in the AD and MCI groups compared with NC. Machine learning models using tract-based features showed good generalizability among independent site cross-validation. The diffusion metrics of the altered regions and the AD probability predicted by the models were highly correlated with cognitive ability in the AD and MCI groups. We highlighted the reproducibility and generalizability of the degeneration pattern of WM tracts in AD.

Humans , White Matter/diagnostic imaging , Diffusion Tensor Imaging/methods , Alzheimer Disease/complications , Reproducibility of Results , Cognition , Cognitive Dysfunction/complications , Brain/diagnostic imaging
Acta Academiae Medicinae Sinicae ; (6): 571-580, 2023.
Article in Chinese | WPRIM | ID: wpr-1008104


Objective To investigate the changes in plasma amyloid-β (Aβ) level and their relationship with white matter microstructure in the patients with amnesic mild cognitive impairment(aMCI) and vascular mild cognitive impairment (vMCI).Methods A total of 36 aMCI patients,20 vMCI patients,and 34 sex and age matched healthy controls (HC) in the outpatient and inpatient departments of the First Affiliated Hospital of Anhui Medical University were enrolled in this study.Neuropsychological scales,including the Mini-Mental State Examination,the Montreal Cognitive Assessment,and the Activity of Daily Living Scale,were employed to assess the participants.Plasma samples of all the participants were collected for the measurement of Aβ42 and Aβ40 levels.All the participants underwent magnetic resonance scanning to obtain diffusion tensor imaging (DTI) data.The DTI indexes of 48 white matter regions of each individual were measured (based on the ICBM-DTI-81 white-matter labels atlas developed by Johns Hopkins University),including fractional anisotropy (FA) and mean diffusivity (MD).The cognitive function,plasma Aβ42,Aβ40,and Aβ42/40 levels,and DTI index were compared among the three groups.The correlations between the plasma Aβ42/40 levels and DTI index of aMCI and vMCI patients were analyzed.Results The Mini-Mental State Examination and the Montreal Cognitive Assessment scores of aMCI and vMCI groups were lower than those of the HC group (all P<0.001).There was no significant difference in the Activity of Daily Living Scale score among the three groups (P=0.654).The plasma Aβ42 level showed no significant difference among the three groups (P=0.227).The plasma Aβ40 level in the vMCI group was higher than that in the HC group (P=0.014),while it showed no significant difference between aMCI and HC groups (P=1.000).The plasma Aβ42/40 levels in aMCI and vMCI groups showed no significant differences from that in the HC group (P=1.000,P=0.105),while the plasma Aβ42/40 level was lower in the vMCI group than in the aMCI group (P=0.016).The FA value of the left anterior limb of internal capsule in the vMCI group was lower than those in HC and aMCI groups (all P=0.001).The MD values of the left superior corona radiata,left external capsule,left cingulum (cingulate gyrus),and left superior fronto-occipital fasciculus in the vMCI group were higher than those in HC (P=0.024,P=0.001,P=0.003,P<0.001) and aMCI (P=0.015,P=0.004,P=0.019,P=0.001) groups,while the MD values of the right posterior limb of internal capsule (P=0.005,P=0.001) and left cingulum (hippocampus) (P=0.017,P=0.031) in the aMCI and vMCI groups were higher than those in the HC group.In the aMCI group,plasma Aβ42/40 level was positively correlated with FA of left posterior limb of internal capsule (r=0.403,P=0.015) and negatively correlated with MD of the right fonix (r=-0.395,P=0.017).In the vMCI group,plasma Aβ42/40 level was positively correlated with FA of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=0.575,P=0.008;r=0.639,P=0.002),while it was negatively correlated with MD of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=-0.558,P=0.011;r=-0.626,P=0.003).Conclusions Plasma Aβ levels vary differently in the patients with aMCI and vMCI.The white matter regions of impaired microstructural integrity differ in the patients with different dementia types in the early stage.The plasma Aβ levels in the patients with aMCI and vMCI are associated with the structural integrity of white matter,and there is regional specificity between them.

Humans , Diffusion Tensor Imaging , White Matter/diagnostic imaging , Cognitive Dysfunction , Outpatients , Cognition , Amyloid beta-Peptides
Journal of Biomedical Engineering ; (6): 1117-1126, 2022.
Article in Chinese | WPRIM | ID: wpr-970649


Constrained spherical deconvolution can quantify white matter fiber orientation distribution information from diffusion magnetic resonance imaging data. But this method is only applicable to single shell diffusion magnetic resonance imaging data and will provide wrong fiber orientation information in white matter tissue which contains isotropic diffusion signals. To solve these problems, this paper proposes a constrained spherical deconvolution method based on multi-model response function. Multi-shell data can improve the stability of fiber orientation, and multi-model response function can attenuate isotropic diffusion signals in white matter, providing more accurate fiber orientation information. Synthetic data and real brain data from public database were used to verify the effectiveness of this algorithm. The results demonstrate that the proposed algorithm can attenuate isotropic diffusion signals in white matter and overcome the influence of partial volume effect on fiber direction estimation, thus estimate fiber direction more accurately. The reconstructed fiber direction distribution is stable, the false peaks are less, and the recognition ability of cross fiber is stronger, which lays a foundation for the further research of fiber bundle tracking technology.

Brain , White Matter/diagnostic imaging , Diffusion Magnetic Resonance Imaging/methods , Algorithms , Databases, Factual , Image Processing, Computer-Assisted/methods
Arq. neuropsiquiatr ; 79(12): 1084-1089, Dec. 2021. graf
Article in English | LILACS | ID: biblio-1355706


ABSTRACT Background: Although epilepsy is primarily known as a cortical disorder, there is growing body of research demonstrating white matter alterations in patients with epilepsy. Objective: To investigate the prevalence of white matter hyperintensities (WMH) and its association with seizure characteristics in patients with epilepsy. Methods: The prevalence of WMH in 94 patients with epilepsy and 41 healthy controls were compared. Within the patient sample, the relationship between the presence of WMH and type of epilepsy, frequency of seizures, duration of disease and the number of antiepileptic medications were investigated. Results: The mean age and sex were not different between patients and healthy controls (p>0.2). WMH was present in 27.7% of patients and in 14.6% of healthy controls. Diagnosis of epilepsy was independently associated with the presence of WMH (ß=3.09, 95%CI 1.06-9.0, p=0.039). Patients with focal epilepsy had higher prevalence of WMH (35.5%) than patients with generalized epilepsy (14.7%). The presence of WMH was associated with older age but not with seizure characteristics. Conclusions: WMH is more common in patients with focal epilepsy than healthy controls. The presence of WMH is associated with older age, but not with seizure characteristics.

RESUMO Antecedentes: Embora a epilepsia seja principalmente conhecida como um distúrbio cortical, há um crescente corpo de pesquisas que demonstra alterações na substância branca em pacientes com epilepsia. Objetivo: Investigar a prevalência de hiperintensidades da substância branca (WMH) e sua associação com características das crises em pacientes com epilepsia. Métodos: A prevalência de WMH em 94 pacientes com epilepsia e 41 controles saudáveis ​​foi comparada. Na amostra de pacientes, foi investigada a relação entre a presença de WMH e o tipo de epilepsia, a frequência das crises, a duração da doença e o número de medicamentos antiepilépticos. Resultados: A média de idade e o sexo não diferiram entre pacientes e controles saudáveis ​​(p>0,2). WMH estava presente em 27,7% dos pacientes, enquanto em 14,6% dos controles saudáveis. O diagnóstico de epilepsia foi independentemente associado à presença de WMH (ß=3,09, IC95% 1,06-9,0, p=0,039). Pacientes com epilepsia focal apresentaram maior prevalência de WMH (35,5%) do que pacientes com epilepsia generalizada (14,7%). A presença de WMH foi associada à idade avançada, mas não a características das crises. Conclusões: Pacientes com epilepsia focal têm WMH mais comum do que controles saudáveis. A presença de WMH está associada à idade avançada, mas não a características das crises epilépticas.

Humans , Aged , Epilepsy/drug therapy , Epilepsy/diagnostic imaging , White Matter/diagnostic imaging , Seizures/epidemiology , Seizures/diagnostic imaging , Magnetic Resonance Imaging
Rev. bras. neurol ; 57(3): 32-36, jul.-set. 2021.
Article in English | LILACS | ID: biblio-1342529


The extensive white matter of the brain, which comprises about one half of its volume, is constituted by an intricate and interwoven assemble of nerve fibers. The WMH (leukoaraiosis) represent the most frequent ischemic type of lesion of SVD, affecting the white matter. These lesions may be apparent or normal appearing on neuroimaging. In both cases such lesions may interrupt the affected white matter fibers, with consequent disconnection syndromes, and atrophy of the denervated grey matter structures. These conditions affect the structural neural networks (connectome), with functional repercussion on the cognitive and behavioral domains.

A extensa substância branca do cérebro, que compreende cerca da metade do seu volume, é constituída por um intricado e entrelaçado conjunto de fibras nervosas. As HSB (hiperintensidades da substância branca) (leucoaraiose) representam o mais frequente tipo de lesão isquêmica da DPV (doença dos pequenos vasos) que afeta a substância branca. Essas lesões podem ser aparentes ou de aparência normal na neuroimagem. Em ambos os casos tais lesões podem interromper essas fibras da substância branca, com consequente síndromes por desconexão e atrofia de estruturas de substância cinzenta desnervadas. Essas condições afetam as redes neurais estruturais (conectoma), com repercussão funcional nos domínios cognitivo e do comportamento.

Humans , Aged , Aged, 80 and over , White Matter/physiopathology , White Matter/diagnostic imaging , Magnetic Resonance Imaging/methods , Denervation , Leukoaraiosis/pathology
Rev. bras. neurol ; 57(2): 14-17, abr.-jun. 2021. tab, ilus
Article in English | LILACS | ID: biblio-1280778


The white matter hyperintensities (WMH, leucoaraiosis) represent the most common kind of ischemic vascular lesion of the white matter due to small vessel diseases, and occurs frequently in the elderly. Consequent to the neuroimaging identification arouse the need for their assessment. The group of Fazekas proposed a systematized semi-quantitative visual scale to score such lesions where two parameters were considered, extent and localization. The original scale was further modified, to a simplified version. Although other more complex scales have appeared, researchers remarked that the relatively simple Fazekas scale, in comparison to the complex ones and to volumetric measures, appeared to be sufficient when analyzing relationships between clinical parameters and WMH load in a clinical setting.

As hiperintensidades da substância branca (HSB, leucoaraiose) representam o tipo de lesão isquêmica mais comum da substância branca decorrente de doenças de pequenos vasos e ocorre frequentemente em idosos. Consequente à identificação por neuroimagem surgiu a necessidade de sua avaliação. O grupo de Fazekas propos uma escala visual semiquantitativa sistematizada para pontuar tais lesões, onde foram considerados dois parâmetros, extensão e localização. A escala original foi modificada para constituir uma versão mais simplificada. Embora outras escalas mais complexas tenham aparecido, pesquisadores comentaram que a relativamente simples escala de Fazekas, em comparação às mais complexas e a método volumétrico, mostrou-se suficiente quando é analisada a relação entre parâmetros clínicos e a carga de HSB em um cenário clínico.

Humans , Aged , Aged, 80 and over , Leukoaraiosis/pathology , Leukoaraiosis/diagnostic imaging , White Matter/diagnostic imaging , Aging , Brain Ischemia/diagnostic imaging , Neuroimaging/methods
Braz. J. Psychiatry (São Paulo, 1999, Impr.) ; 43(2): 147-152, Mar.-Apr. 2021. tab
Article in English | LILACS | ID: biblio-1285532


Objective: The increased prevalence rate of white matter hyperintensities is one of the most consistently reported brain abnormalities in adults with bipolar disorder. However, findings in children and adolescents with bipolar disorder are less consistent. Prior studies have been constrained by small sample sizes and/or poor age- and sex-matching of healthy controls. We examined this topic in the largest sample of adolescents with bipolar disorder to date. Methods: T2-weighted 3-Tesla magnetic resonance imaging data were acquired for 83 adolescents with bipolar disorder diagnosed via the Kiddie Schedule for Affective Disorders and the Schizophrenia, Present and Lifetime version semi-structured interview and 64 age- and sex-matched healthy controls. All acquired scans were examined by neuroradiologists and the presence or absence of white matter hyperintensities was determined for each participant. Results: The prevalence of white matter hyperintensities did not differ between adolescents with bipolar disorder (13.3%) and controls (21.9%; χ2 = 1.90; p = 0.168). Conclusion: In contrast to the study hypothesis, the prevalence of white matter hyperintensities was not higher in adolescents with bipolar disorder than controls. The large sample size and good matching for age and sex bolster the reliability of this negative finding. Future studies are warranted to evaluate the prevalence, incidence, and predictors of white matter hyperintensities in early-onset bipolar disorder prospectively.

Humans , Child , Adolescent , Young Adult , Bipolar Disorder/epidemiology , Bipolar Disorder/diagnostic imaging , White Matter/diagnostic imaging , Brain/diagnostic imaging , Magnetic Resonance Spectroscopy , Prevalence , Reproducibility of Results
Frontiers of Medicine ; (4): 125-138, 2021.
Article in English | WPRIM | ID: wpr-880937


This study aimed to define the most consistent white matter microarchitecture pattern in Parkinson's disease (PD) reflected by fractional anisotropy (FA), addressing clinical profiles and methodology-related heterogeneity. Web-based publication databases were searched to conduct a meta-analysis of whole-brain diffusion tensor imaging studies comparing PD with healthy controls (HC) using the anisotropic effect size-signed differential mapping. A total of 808 patients with PD and 760 HC coming from 27 databases were finally included. Subgroup analyses were conducted considering heterogeneity with respect to medication status, disease stage, analysis methods, and the number of diffusion directions in acquisition. Compared with HC, patients with PD had decreased FA in the left middle cerebellar peduncle, corpus callosum (CC), left inferior fronto-occipital fasciculus, and right inferior longitudinal fasciculus. Most of the main results remained unchanged in subgroup meta-analyses of medicated patients, early stage patients, voxel-based analysis, and acquisition with 30 diffusion directions. The subgroup meta-analysis of medication-free patients showed FA decrease in the right olfactory cortex. The cerebellum and CC, associated with typical motor impairment, showed the most consistent FA decreases in PD. Medication status, analysis approaches, and the number of diffusion directions have an important impact on the findings, needing careful evaluation in future meta-analyses.

Humans , Anisotropy , Brain/diagnostic imaging , Corpus Callosum , Diffusion Tensor Imaging , Parkinson Disease/diagnostic imaging , White Matter/diagnostic imaging
Acta Physiologica Sinica ; (6): 407-422, 2021.
Article in Chinese | WPRIM | ID: wpr-887677


As the two essential components, the white matter and gray matter compose the central nervous system of the brain. Widely known that axons of neurons mainly form the white matter, and these formed nerve fibers are responsible for transmitting information among various brain regions to achieve the coordinated operation of the entire brain. Early research on the white matter could only be done by dissecting living animals or human cadavers, until Basser et al. proposed diffusion tensor imaging (DTI) technology in 1994, which could detect the diffusion characteristics of water in the brain in vivo noninvasively. Accordingly, this technology could be applied to investigate the diffusion movement of water in white matter to obtain the information of direction and micro-anatomy of white matter fiber bundles. With the advancement on the display and analysis of the anatomical structure of white matter fiber bundles, the exploration of microscopic pathological changes, and the assistance of clinical diagnosis and neurophysiological research, DTI technology has become one of the most popular topics in brain science research. Chronic pain refers to pain lasting more than three months, which not only seriously affects the patient's physical and social functions, but also dramatically reduces the quality of life. It was reported that long-term pain stimulation might cause pathological remodeling of the central nervous system, and abnormalities in white matter were found in imaging examinations of patients with chronic pain. This review introduces the quantitative analysis methods of white matter fiber bundle microstructure based on DTI and its application in chronic pain, and further discusses the application value of DTI technology on clinical research of chronic pain.

Animals , Humans , Brain , Chronic Pain/diagnostic imaging , Diffusion Tensor Imaging , Quality of Life , White Matter/diagnostic imaging
Journal of Peking University(Health Sciences) ; (6): 341-347, 2020.
Article in Chinese | WPRIM | ID: wpr-942185


OBJECTIVE@#To construct and verify a standard template of white matter based on Chinese normal 0 to 2 years old infants by using nonlinear high registration accuracy of non-rigid diffeomorphism paradigm (large deformation diffeomorphic metric mapping, LDDMM).@*METHODS@#Full-term spontaneous labor children without maternal pregnancy disease (hypertension, diabetes, etc.), intrauterine hypoxia and ischemia, head trauma, intracranial infection, intracranial surgery history, family history of mental disorders were selected. Diffusion tensor imaging (DTI) data from the 120 normal Chinese infants under 2 years old were acquired after excluding the existence of neurological diseases revealed by neurologists, radiologists and Gesell Developmental Scale. All the data were divided into six groups including group A: 1 day to 1.5 months, group B: 1.5 to 4.5 months, group C: 4.5 to 9.0 months, group D: 9 to 15 months, group E: 15 to 21 months, and group F: 21 to 24 months. Data pre-processing, normalizing, tensor fitting and calculation of all the images were performed by using MRlcron, DtiStudio, DiffeoMap and SPM software package combined with LDDMM image registration method based on the selected single template of each group. And the average templates of each group were constructed by MATLAB software platform. The set of templates included fractional anisotropy figure (FA), color map, T1 weighted image, b0 image and the mean of all DWfs figures.@*RESULTS@#The templates of FA, T1, b0, DWfs and color map for the normal brain magnetic resonance white matter development of the Chinese infants aged 0 to 2 years were successfully established with the subjective scores exceeding 2 points. The objective evaluation root mean squared error was controlled below 0.19, and the cubic chart of brain alternation trend for the children aged 0 to 2 years was consistent with previous literature.@*CONCLUSION@#Constructing a standard template of white matter based on Chinese normal infants, by using nonlinear high registration accuracy of non-rigid diffeomorphism paradigm provides not only a foundation of further research on brain development, mechanism and treatment of pediatric diseases associated with brain, but also objective and fair imaging information for medical education and research.

Child , Child, Preschool , Humans , Infant , Infant, Newborn , Brain/diagnostic imaging , Diffusion Tensor Imaging , Image Processing, Computer-Assisted , Magnetic Resonance Spectroscopy , Software , White Matter/diagnostic imaging
Rev. argent. radiol ; 83(3): 95-101, set. 2019. ilus, tab
Article in Spanish | LILACS | ID: biblio-1057407


Objetivo Desde la aparición de la tractografía, al tratarse de una técnica no invasiva y que usa la ampliamente conocida resonancia magnética (RM), el estudio de la sustancia blanca se ha facilitado. A partir de eso, se han logrado grandes descubrimientos en cuanto a fascículos cerebrales involucrados en funciones cognitivas. Sin embargo, su evaluación sigue siendo subjetiva y depende de la experiencia y entrenamiento del evaluador, razón por la cual se ha limitado su aplicabilidad en la práctica clínica. En ese sentido, es conveniente parametrizar volúmenes cerebrales de sustancia blanca en población sana a través de una herramienta electrónica que se pueda reproducir y así poderlo aplicar en enfermos. Materiales y métodos Se reportan 10 sujetos sanos desde el punto de vista neurológico. Para cada sujeto, se adquirieron imágenes ponderadas por difusión y los resultados se visualizaron mediante FiberNavigator ( Finalmente, esa misma herramienta fue utilizada para purificar los fascículos objeto de estudio y realizar el conteo de las fibras. Resultados Se obtuvieron valores de volumetría del fascículo longitudinal superior (FLS), fascículo longitudinal inferior (FLI), fascículo frontoccipital inferior (FFI), fascículo uncinado (FU) y fascículo del cíngulo (FC), identificando que no existen diferencias estadísticamente significativas entre el número de fibras que componen los fascículos cerebrales. Discusión Los resultados alcanzados de la anatomía y la direccionalidad de fibras de los fascículos cerebrales de este estudio coinciden con el resto de la evidencia publicada hasta el momento, sin encontrar diferencias en cuanto a su organización y recorrido. Conclusión Aunque esos resultados no sirven como valores de referencia para ser aplicados en pacientes con patología neurológica, brindamos información inexistente hasta el momento, con ese equipo en específico y la reproducción entre los distintos usuarios y el software.

Objective Since the appearance of tractography, as it is a non-invasive technique and uses the widely known magnetic resonance (MR), the study of white matter has been facilitated. After this, great discoveries have been made regarding the brain fascicles involved in cognitive functions. However, its evaluation continues to be subjective and depends on the evaluator's experience and training. That the reason why its applicability has been limited in clinical practice. Because of this, it is convenient to parametrize cerebral volumes of white matter in healthy population through an electronic, reproducible tool that could be applied in patients. Materials and Methods Ten neurologically healthy subjects are reported, for each subject we acquired images weighted by diffusion and the results were visualized by means of FiberNavigator ( Finally, this same tool was used to purify the fascicles under study and perform the fiber count. Results Volumetric values of the upper longitudinal fasciculus, inferior longitudinal fasciculus, inferior frontoccipital fasciculus, uncinated fasciculus and cingulate fasciculus were obtained, identifying that there are not statistically significant differences in the number of fibers that make up the cerebral fascicles. Discussion The results achieved of the anatomical and fiber directionality of the cerebral fascicles of this study, coincide with the rest of the evidence published up to now, without finding differences regarding its organization and route. Conclusion Although these results do not serve as reference values to be applied in patients with neurological pathology, do we provide nonexistent information so far, with this specific equipment and the reproducibility between the different users and the software.

Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Cognition/physiology , White Matter/diagnostic imaging , Reference Values , Anisotropy , Titrimetry/standards , Diffusion Tensor Imaging/standards , Nerve Fibers
Braz. J. Psychiatry (São Paulo, 1999, Impr.) ; 41(2): 101-111, Mar.-Apr. 2019. tab, graf
Article in English | LILACS | ID: biblio-990827


Objective: To compare results of positron emission tomography (PET) with carbon-11-labeled Pittsburgh compound B (11C-PIB) obtained with cerebellar or global brain uptake for voxel intensity normalization, describe the cortical sites with highest tracer uptake in subjects with mild Alzheimer's disease (AD), and explore possible group differences in 11C-PIB binding to white matter. Methods: 11C-PIB PET scans were acquired from subjects with AD (n=17) and healthy elderly controls (n=19). Voxel-based analysis was performed with statistical parametric mapping (SPM). Results: Cerebellar normalization showed higher 11C-PIB uptake in the AD group relative to controls throughout the cerebral cortex, involving the lateral temporal, orbitofrontal, and superior parietal cortices. With global uptake normalization, greatest cortical binding was detected in the orbitofrontal cortex; decreased 11C-PIB uptake in white matter was found in the posterior hippocampal region, corpus callosum, pons, and internal capsule. Conclusion: The present case-control voxelwise 11C-PIB PET comparison highlighted the regional distribution of amyloid deposition in the cerebral cortex of mildly demented AD patients. Tracer uptake was highest in the orbitofrontal cortex. Decreased 11C-PIB uptake in white-matter regions in this patient population may be a marker of white-matter damage in AD.

Humans , Male , Female , Aged , Aged, 80 and over , Carbon Radioisotopes , Cerebral Cortex/diagnostic imaging , Positron-Emission Tomography/methods , Alzheimer Disease/diagnostic imaging , White Matter/diagnostic imaging , Severity of Illness Index , Case-Control Studies
Trends psychiatry psychother. (Impr.) ; 40(4): 277-284, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-979442


Abstract Introduction: Bipolar disorder (BD) is a debilitating mood condition that affects approximately 1.3% of people worldwide, although some studies report up to 3.9% lifetime prevalence and 4-6% in adults when broad diagnostic criteria are applied. Objective: To compare differences in total white matter (WM), corpus callosum (CC) and total gray matter (GM) volumes in patients with type I BD at early and late stages compared with controls. Methods: Fifty-five subjects were enrolled in this study protocol. The double case-control design included 14 patients with BD at early stage; 15 patients at late stage; and their respective matched controls (14 and 12 subjects). Results: CC and total WM volumes were significantly smaller in patients with BD at early and late stages vs. controls. There was no difference for total GM volume in the early stage group, but in patients at late stage total GM volume was significantly smaller than in controls. The total GM volume reduction in patients at late stage is in agreement with the neuroprogression theory of BD. The reduction of WM volumes in total WM and in the CC at early and late stages supports the possibility that an early demyelination process could occur underlying the clinical manifestation of BD. Conclusion: Our findings may direct to the investigation of WM abnormalities in populations at high risk to develop BD, perhaps as early biomarkers before the overt syndrome.

Resumo Introdução: O transtorno do humor bipolar (THB) é uma condição debilitante que afeta aproximadamente 1,3% das pessoas em todo o mundo, embora alguns estudos relatem uma prevalência acumulada de até 3,9% e de 4-6% em adultos quando os critérios diagnósticos mais abrangentes são aplicados. Objetivo: Comparar as diferenças nos volumes totais de substância branca (SB), corpo caloso (CC) e volume total de substância cinzenta (SC) em pacientes com THB tipo I em estágios iniciais e tardios em comparação com controles. Métodos: Cinquenta e cinco sujeitos foram incluídos neste protocolo de estudo. O desenho de caso com duplo controle incluiu 14 pacientes com THB em estágio inicial; 15 pacientes com THB em fase tardia; e seus respectivos controles correspondentes (14 e 12 sujeitos). Resultados: Os volumes do CC e total de SB foram significativamente menores nos pacientes com THB nos estágios iniciais e tardios vs. controles. Não houve diferença para o volume total de SC no grupo em estágio inicial, mas em pacientes em fase tardia o volume total de SC foi significativamente menor do que nos controles. A redução do volume total de SC em pacientes em fase tardia está de acordo com a teoria da neuroprogressão do THB. A redução dos volumes de SB em SB total e no CC em fases precoces e tardias suporta a possibilidade de que um processo de desmielinização precoce poderia ocorrer subjacente à manifestação clínica de THB. Conclusão: Nossos achados podem direcionar a investigação de anormalidades da SB em populações de alto risco para o desenvolvimento de THB, talvez como biomarcadores precoces antes da síndrome aberta.

Humans , Male , Female , Adult , Bipolar Disorder/diagnostic imaging , White Matter/diagnostic imaging , Organ Size , Bipolar Disorder/pathology , Magnetic Resonance Imaging , Case-Control Studies , Disease Progression , Corpus Callosum/pathology , Corpus Callosum/diagnostic imaging , Gray Matter/pathology , Gray Matter/diagnostic imaging , White Matter/pathology , Middle Aged
Egyptian Journal of Hospital Medicine [The]. 2018; 71 (4): 3001-3006
in English | IMEMR | ID: emr-192559


Background: Multiple sclerosis [MS] is an inflammatory demyelinating condition of the central nervous system [CNS] that is generally considered to be autoimmune in nature. White matter tracts are affected, including those of the cerebral hemispheres, infratentorium, and spinal cord. Several methods have been proposed, mainly using conventional MR modalities like T1, FLAIR or T2 images and enhanced MRI to delineate lesions. Conventional MR techniques cannot give detailed information about the integrity and location of WM tracts. Diffusion MRI is one of the non-conventional MRI techniques used for assessment of multiple sclerosis. The emergence of diffusion tensor imaging [DTI] is of great interest in MS. DTI probe the details of water diffusion within tissues, and could therefore reveal alterations in normal appearing white matter fibers before being visible in conventional MRI. Fractional anisotropy [FA], is the measure of the portion of the diffusion tensor that results from anisotropy [i.e, a measure of the directionality of the molecular motion of water]

Purpose: to evaluate the role of diffusion tensor imaging [DTI] in the examination of the brain white matter that shows normal appearance on conventional MRI sequences in patients with MS, thus assessing its ability to detect early abnormalities at diffusion level

Methods: the study included 50 patients; 38 females and 12 males having MS [between 20 and 40 years of age] referred from Neurologists to Radiodiagnosis Department with 10 ages' matched healthy control volunteers. Each patient included in the study was subjected to full history taking, reviewing medical sheet and MR examination including: Conventional MR examination and Diffusion Tensor imaging. Technique was performed using a standard 3 Tesla unit [Acheiva, Philips]

Results: the study showed that DTI can reveal normal appearing white matter affection in MS cases before visible sizable plaques can be detected by conventional MRI

Conclusion: the current application of diffusion MRI to patients with MS shows that it has enhanced our understanding of the disease pathophysiology. The study reviewed here provides evidence that DTI-derived measures are more specific to the disease pathological processes and sensitive to the diffuse microscopic injury in the NAWM

Humans , Male , Female , Adult , Diffusion Tensor Imaging , Diffusion Magnetic Resonance Imaging , Magnetic Resonance Imaging , White Matter/diagnostic imaging
Braz. j. med. biol. res ; 51(11): e7653, 2018. tab, graf
Article in English | LILACS | ID: biblio-951724


This study aimed to explore attentional patterns among children with inattentive attention-deficit/hyperactivity disorder (ADHD-I) and children with typical development (TD), using a latent class analysis (LCA). Patterns of brain connectivity were also explored. The sample comprised 29 ADHD-I and 29 TD matched children. An LCA was conducted to reclassify subjects according to their attentional performance, considering cognitive measures of attention and behavioral symptoms, regardless of group of origin. The new clusters were then compared in respect to brain white matter measurements (extracted from diffusion tensor imaging). Participants were rearranged in 2 new latent classes, according to their performance in an attention task and the results of behavioral scales, resulting in groups with more homogeneous attentional profiles. A comparison of the 2 new classes using the white matter measurements revealed increased fractional anisotropy in the left inferior fronto-occipital fasciculus and left inferior longitudinal fasciculus for the class composed by participants with a higher risk of attentional problems. The findings indicated that it was possible to observe variability regarding neuropsychological profile, accompanied by underpinning neurobiological differences, even among individuals with the same disorder subtype - inattentive ADHD. This specific data-driven clustering analysis may help to enhance understanding of the pathophysiology of the disorder's phenotypes.

Humans , Male , Female , Child , Adolescent , Attention/physiology , Attention Deficit Disorder with Hyperactivity/physiopathology , White Matter/physiopathology , Reaction Time/physiology , Reference Standards , Reference Values , Attention Deficit Disorder with Hyperactivity/diagnosis , Case-Control Studies , Statistics as Topic/methods , Anisotropy , Cognition/physiology , Diffusion Tensor Imaging/methods , White Matter/diagnostic imaging , Neuropsychological Tests
Arq. neuropsiquiatr ; 75(11): 778-784, Nov. 2017. graf
Article in English | LILACS | ID: biblio-888263


ABSTRACT The low-educated elderly are a vulnerable population in whom studying the role of white matter integrity on memory may provide insights for understanding how memory declines with aging and disease. Methods: Thirty-one participants (22 women), 23 cognitively healthy and eight with cognitive impairment-no dementia, aged 80.4 ± 3.8 years, with 2.2 ± 1.9 years of education, underwent an MRI scan with diffusion tensor imaging (DTI) acquisition. We verified if there were correlations between the performance on the Brief Cognitive Screening Battery (BCSB) and the Rey Auditory Verbal Learning Test (RAVLT) with DTI parameters. Results: The BCSB delayed recall task correlated with frontotemporoparietal connection bundles, with the hippocampal part of the cingulum bilaterally and with the right superior longitudinal fasciculus. The RAVLT learning and delayed recall scores also correlated with the hippocampal part of the cingulum bilaterally. Conclusions: Although preliminary, our study suggests that the integrity of white matter frontotemporoparietal fasciculi seems to play a role in episodic memory performance in the low-educated elderly. This finding opens opportunities to study potential targets for memory decline prevention in vulnerable populations.

RESUMO Idosos de baixo nível educacional representam uma população vulnerável em que o estudo do papel da integridade da substância branca na memória pode revelar como essa declina no envelhecimento. Métodos: Trinta e um indivíduos (22 mulheres), sendo 23 cognitivamente saudáveis, oito com comprometimento cognitivo não demência, 80,4 ± 3,8 anos de idade e 2,2 ± 1,9 anos de escolaridade, foram submetidos à RM com imagem de tensor de difusão, cujos parâmetros foram correlacionados com a Bateria Cognitiva Breve (BCSB) e o Teste Auditivo Verbal de Rey (RAVLT). Resultados: A evocação tardia da BCSB correlacionou-se com fascículos de conexão frontotemporoparietal, fascículo longitudinal superior direito e cíngulo parte hipocampal bilateral, sendo que esse último também correlacionou com o RAVLT (aprendizado e evocação tardia). Conclusão: Apesar de preliminar, nosso estudo sugere que a integridade da substância branca parece ser importante para a memória em idosos de baixa escolaridade, achado que revela alvo potencial na prevenção do seu declínio em populações vulneráveis.

Humans , Male , Female , Aged , Aged, 80 and over , White Matter/diagnostic imaging , Memory Disorders/diagnostic imaging , Magnetic Resonance Imaging , Educational Status , Diffusion Tensor Imaging , White Matter/pathology , Memory Disorders/etiology , Memory Disorders/pathology , Neuropsychological Tests
Arq. neuropsiquiatr ; 75(8): 503-508, Aug. 2017. tab, graf
Article in English | LILACS | ID: biblio-888310


ABSTRACT Objective To evaluate the role of the involvement of white matter tracts in huntingtin gene mutation patients as a potential biomarker of the progression of the disease. Methods We evaluated 34 participants (11 symptomatic huntingtin gene mutation, 12 presymptomatic huntingtin gene mutation, and 11 controls). We performed brain magnetic resonance imaging to assess white matter integrity using diffusion tensor imaging, with measurement of fractional anisotropy. Results We observed a significant decrease of fractional anisotropy in the cortical spinal tracts, corona radiate, corpus callosum, external capsule, thalamic radiations, superior and inferior longitudinal fasciculus, and inferior frontal-occipital fasciculus in the Huntington disease group compared to the control and presymptomatic groups. Reduction of fractional anisotropy is indicative of a degenerative process and axonal loss. There was no statistically significant difference between the presymptomatic and control groups. Conclusion White matter integrity is affected in huntingtin gene mutation symptomatic individuals, but other studies with larger samples are required to assess its usefulness in the progression of the neurodegenerative process.

RESUMO Objetivo Avaliar o envolvimento da substância branca (SB) cerebral em indivíduos com mutação do gene da huntingtina. Métodos Foram avaliados 34 indivíduos: 11 com mutação do gene da huntingtina sintomática, 12 assintomáticos com mutação do gene da huntingtina e 11 indivíduos controles. Realizamos ressonância magnética cerebral para avaliar a integridade da SB usando o tensor de difusão (DTI), com medição da anisotrofia fracionada (FA). Resultados Observamos uma diminuição da FA no trato corticoespinhal, coroa radiada, corpo caloso (joelho, corpo e esplênio), cápsula externa, radiações talâmicas, fascículo longitudinal superior e inferior, e fascículo frontal-occipital inferior no grupo dos indivíduos com mutação sintomática. A redução da FA é indicativa de processo degenerativo e perda axonal. Não houve diferença estatística entre os grupos controle e pré-sintomático. Conclusão Houve comprometimento da integridade da SB em indivíduos com mutação no gene da Huntingtina sintomática, mas outros estudos são necessários para avaliar a sua utilidade na progressão do processo neurodegenerativo.

Humans , Male , Female , Adult , Middle Aged , Magnetic Resonance Imaging/methods , Huntington Disease/genetics , Huntington Disease/diagnostic imaging , Diffusion Tensor Imaging/methods , White Matter/diagnostic imaging , Mutation , Anisotropy , Corpus Callosum/pathology , Mental Status Schedule
Rev. argent. radiol ; 81(2): 110-121, jun. 2017. ilus, tab
Article in Spanish | LILACS | ID: biblio-897410


En Neurorradiología los cambios de la sustancia blanca periventricular o subcortical en pacientes ancianos son descritos generalmente con leucoaraiosis, fenómenos hipóxico-isquémicos crónicos, leucoencefalopatía microangiopática o simplemente con alteraciones en la densidad o intensidad según el método elegido. Sin embargo, ¿es correcto el empleo de estas denominaciones?, ¿funcionan como sinónimos?, ¿tienen un mismo mecanismo de producción? Las lesiones que afectan a la sustancia blanca se aprecian hipodensas en tomografía computada, hiperintensas en las secuencias ponderadas en T2 o FLAIR e hipointensas en la resonancia magnética en ponderación T1. Describimos las distintas entidades que pueden afectar selectivamente la sustancia blanca en el paciente anciano y sus probables mecanismos de acción, para establecer una correcta denominación y realizar los diagnósticos diferenciales.

In Neuroradiology the changes in the deep or sub-cortical white matter in elderly people are generally described as leukoaraiosis, chronic hypoxic-ischaemic processes, microangiopathic leucoencephalopathy, or they are simply mentioned as density or intensity changes according to the selected imaging method. However, are these terms correct?, Are they synonyms?, Do they have the same aetiology? The lesions that affect white matter are hypodense in computed tomography, hyperintense in T2-weighted or FLAIR, or hypointense in T1 images in magnetic resonance. A description is presented on the different conditions that can selectively affect the white matter in the elderly patient and their probable mechanisms of action in order to establish a correct nomenclature, as well as make differential diagnoses.

Humans , Aged, 80 and over , Terminology , Leukoaraiosis/diagnostic imaging , White Matter/injuries , Magnetic Resonance Spectroscopy , Leukoaraiosis/classification , Leukoaraiosis/etiology , Cerebrum/diagnostic imaging , Leukoencephalopathies/diagnostic imaging , White Matter/diagnostic imaging
Arq. neuropsiquiatr ; 75(5): 272-276, May 2017. tab, graf
Article in English | LILACS | ID: biblio-838901


ABSTRACT The objective of this preliminary study was to correlate diffusion tensor imaging (DTI) alterations with the cognitive profile of patients with amyotrophic lateral sclerosis (ALS). Methods This was a case-control study conducted from December 1, 2012 to December 1, 2014. Clinical and demographic data were recorded. A neuropsychological test battery adapted to ALS patients was used. An MRI with DTI was performed in all patients and fractional anisotropy (FA) was analyzed in the white matter using the tract based spatial statistics program. Results Twenty-four patients with ALS (15 females, mean age 66.9 + -2.3) and 13 healthy controls (four females, average age 66.9 + - 2) were included. The DTI showed white matter damage in ALS patients vs. healthy controls (p < 0.001). Discussion In our preliminary study the alterations of white matter in DTI were significantly associated with cognitive impairment in patients with ALS.

RESUMEN El objetivo del presente estudio preliminar fue correlacionar alteraciones del Tensor de Difusión (TD) con el perfil cognitivo de pacientes con Esclerosis Lateral Amiotrofica (ELA). Metodos Se realizó estudio casos-controles entre el 1 de Diciembre del 2012 hasta el 1 de Diciembre del 2014. Se registraron datos clínicos y demográficos. Se utilizó batería de tests neuropsicológicos adaptada a ELA. Se realizó RMN de cerebro con TD en todos los pacientes, la Fracción de Anisotropía (FA) se analizó en sustancia blanca, utilizando el programa Tract Based Spatial Statistics. Resultados Se incluyeron 24 pacientes con ELA (15 mujeres, edad media 66.9 + -2.3) y 13 controles sanos (4 mujeres, edad media 66.9 +-2). El TD mostró daño en sustancia blanca en los pacientes con ELA vs controles (p < 0.001). Discusión En nuestro estudio preliminar las alteraciones de sustancia blanca en TD se asociaron significativamente con alteraciones cognitivas en pacientes con ELA.

Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Diffusion Tensor Imaging , Cognitive Dysfunction/diagnostic imaging , White Matter/diagnostic imaging , Amyotrophic Lateral Sclerosis/complications , Biomarkers , Case-Control Studies , Cognitive Dysfunction/etiology , Cognitive Dysfunction/pathology , White Matter/pathology , Amyotrophic Lateral Sclerosis/pathology , Amyotrophic Lateral Sclerosis/diagnostic imaging , Neuropsychological Tests