RESUMEN

Focal epilepsy is characterized by repeated spontaneous seizures that originate from cortical epileptogenic zone networks (EZN). Analysis of intracerebral recordings showed that subcortical structures, and in particular the thalamus, play an important role in seizure dynamics as well, supporting their structural alterations reported in the neuroimaging literature. Nonetheless, between-patient differences in EZN localization (e.g., temporal vs. non-temporal lobe epilepsy) as well as extension (i.e., number of epileptogenic regions) might impact the magnitude as well as spatial distribution of subcortical structural changes. Here we used 7 Tesla MRI T1 data to provide an unprecedented description of subcortical morphological (volume, tissue deformation, and shape) and longitudinal relaxation (T1 ) changes in focal epilepsy patients and evaluate the impact of the EZN and other patient-specific clinical features. Our results showed variable levels of atrophy across thalamic nuclei that appeared most prominent in the temporal lobe epilepsy group and the side ipsilateral to the EZN, while shortening of T1 was especially observed for the lateral thalamus. Multivariate analyses across thalamic nuclei and basal ganglia showed that volume acted as the dominant discriminator between patients and controls, while (posterolateral) thalamic T1 measures looked promising to further differentiate patients based on EZN localization. In particular, the observed differences in T1 changes between thalamic nuclei indicated differential involvement based on EZN localization. Finally, EZN extension was found to best explain the observed variability between patients. To conclude, this work revealed multi-scale subcortical alterations in focal epilepsy as well as their dependence on several clinical characteristics.

Asunto(s)

Epilepsias Parciales , Epilepsia del Lóbulo Temporal , Humanos , Epilepsias Parciales/diagnóstico por imagen , Ganglios Basales/diagnóstico por imagen , Convulsiones , Tálamo/diagnóstico por imagen , Imagen por Resonancia Magnética

RESUMEN

OBJECTIVES: To characterize the neuroanatomy of BD in youth and its correlation to clinical characteristics. METHODS: The current study includes a sample of 105 unmedicated youth with first-episode BD, aged between 10.1 and 17.9 years, and 61 healthy comparison adolescents, aged between 10.1 and 17.7 years, who were matched for age, race, sex, socioeconomic status, intelligence quotient (IQ), and education level. T1-weighted magnetic resonance imaging (MRI) images were obtained using a 4 T MRI scanner. Freesurfer (V6.0) was used to preprocess and parcellate the structural data, and 68 cortical and 12 subcortical regions were considered for statistical comparisons. The relationship between morphological deficits and clinical and demographic characteristics were evaluated using linear models. RESULTS: Compared with healthy youth, youth with BD had decreased cortical thickness in frontal, parietal, and anterior cingulate regions. These youth also showed decreased gray matter volumes in 6 of the 12 subcortical regions examined including thalamus, putamen, amygdala and caudate. In further subgroup analyses, we found that youth with BD with comorbid attention-deficit hyperactivity disorder (ADHD) or with psychotic symptoms had more significant deficits in subcortical gray matter volume. LIMITATIONS: We cannot provide information about the course of structural changes and impact of treatment and illness progression. CONCLUSIONS: Our findings indicate that youth with BD have significant neurostructural deficits in both cortical and subcortical regions mainly located in the regions related to emotion processing and regulation. Variability in clinical characteristics and comorbidities may contribute to the severity of anatomic alterations in this disorder.

Asunto(s)

Trastorno Bipolar , Humanos , Adolescente , Niño , Trastorno Bipolar/diagnóstico por imagen , Trastorno Bipolar/epidemiología , Trastorno Bipolar/patología , Encéfalo/patología , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Imagen por Resonancia Magnética/métodos , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/patología

RESUMEN

BACKGROUND: Acute cerebrovascular accidents, long-term hypoperfusion, and/or remote neuronal degeneration may lead to structural alterations in patients with moyamoya disease (MMD). This study sought to comprehensively investigate the distribution characteristics of subcortical gray matter volume and their correlations with angiographic changes in the intracranial artery in patients with MMD. METHOD: One hundred forty-two patients with MMD and 142 age- and sex-matched healthy controls underwent 3-dimensional high-resolution structural magnetic resonance imaging. Volumes of subcortical gray matter and subregions of the hippocampus and amygdala were calculated, and the degree of stenosis/occlusion of intracranial arteries in patients with MMD was evaluated on MR angiography. RESULTS: Volume reductions in the thalamus, caudate, putamen, hippocampus, amygdala, pallidum, and nucleus accumbens were found in patients with MMD. Hippocampal subfields and amygdala subnuclei in patients with MMD showed distinct vulnerability, and morphological alterations in specific subregions were more obvious than in the whole hippocampus/amygdala. Volume loss in several subcortical areas was related to disease duration and intracranial arterial changes. CONCLUSIONS: Our findings revealed structural alteration patterns of subcortical gray matter in MMD. The specific atrophy in subregions of the hippocampus and the amygdala suggested potential cognitive and affective impairments in MMD, which warrants further investigation. Chronic cerebral hemodynamic alterations in MMD may play a pivotal role in morphological changes in subcortical areas.

Asunto(s)

Sustancia Gris , Enfermedad de Moyamoya , Humanos , Adulto , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Enfermedad de Moyamoya/diagnóstico por imagen , Núcleo Accumbens , Imagen por Resonancia Magnética/métodos , Atrofia/patología , Encéfalo/patología

RESUMEN

Telomere shortening is theorized to accelerate biological aging, however, this has not been tested in the brain and cognitive contexts. We used machine learning age-prediction models to determine brain/cognitive age and quantified the degree of accelerated aging as the discrepancy between brain and/or cognitive and chronological ages (i.e., age gap). We hypothesized these age gaps are associated with telomere length (TL). Using healthy participants from the ADNI-3 cohort (N = 196, Agemean=70.7), we trained age-prediction models using 4 modalities of brain features and cognitive scores, as well as a 'stacked' model combining all brain modalities. Then, these 6 age-prediction models were applied to an independent sample diagnosed with mild cognitive impairment (N = 91, Agemean=71.3) to determine, for each subject, the model-specific predicted age and age gap. TL was most strongly associated with age gaps from the resting-state functional connectivity model after controlling for confounding variables. Overall, telomere shortening was significantly related to older brain but not cognitive age gaps. In particular, functional relative to structural brain-age gaps, were more strongly implicated in telomere shortening.

Asunto(s)

Disfunción Cognitiva , Acortamiento del Telómero , Envejecimiento/genética , Envejecimiento/psicología , Encéfalo , Humanos , Aprendizaje Automático , Telómero/genética

RESUMEN

Pain is one of the manifestations of hip disorder and has been proven to lead to the remodeling of somatotopic map plasticity in the cortex. However, most studies are volume-based which may lead to inaccurate anatomical positioning of functional data. The methods that work on the cortical surface may be more sensitive than those using the full brain volume and thus be more suitable for map plasticity study. In this prospective cross-sectional study performed in Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, China, 20 patients with osteonecrosis of the femoral head (12 males and 8 females, aged 56.80 ± 13.60 years) and 20 healthy controls (9 males and 11 females, aged 54.56 ± 10.23 years) were included in this study. Data of resting-state functional magnetic resonance imaging were collected. The results revealed that compared with healthy controls, compared with the healthy controls, patients with osteonecrosis of the femoral head (ONFH) showed significantly increased surface-based regional homogeneity (ReHo) in areas distributed mainly in the left dorsolateral prefrontal cortex, frontal eye field, right frontal eye field, and the premotor cortex and decreased surface-based ReHo in the right primary motor cortex and primary sensory cortex. Regions showing significant differences in surface-based ReHo values between the healthy controls and patients with ONFH were defined as the regions of interests. Seed-based functional connectivity was performed to investigate interregional functional synchronization. When the areas with decreased surface-based ReHo in the frontal eye field and right premotor cortex were used as the regions of interest, compared with the healthy controls, the patients with ONFH displayed increased functional connectivity in the right middle frontal cortex and right inferior parietal cortex and decreased functional connectivity in the right precentral cortex and right middle occipital cortex. Compared with healthy controls, patients with ONFH showed significantly decreased cortical thickness in the para-insular area, posterior insular area, anterior superior temporal area, frontal eye field and supplementary motor cortex and reduced volume of subcortical gray matter nuclei in the right nucleus accumbens. These findings suggest that hip disorder patients showed cortical plasticity changes, mainly in sensorimotor- and pain-related regions. This study was approved by the Medical Ethics Committee of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine (approval No. 2018-041) on August 1, 2018.

RESUMEN

PURPOSE: Several studies reported gadolinium deposition in the dentate nuclei (DN) and the globus pallidus (GP) that was associated to linear GBCA administrations rather than macrocyclic. It is therefore imperative to evaluate and assess the safety of cumulative administration of gadoterate meglumine (macrocyclic). Thus, T1-weighted images (T1WI) of multiple sclerosis (MS) patients longitudinally followed for 4 years were retrospectively analyzed. METHODS: In this study 44 patients, 10 with clinically isolated syndrome (CIS), 24 relapsing-remitting MS (RRMS) and 10 primary-progressive MS (PPMS) were examined every 6 months (first four scans) and then with a 1-year interval (last two scans). Image processing consisted in reorienting unenhanced T1WI to standard space, followed by B1 inhomogeneity correction. A patient-specific template was then generated to normalize T1WI signal intensity (SI) and segment the DN and subcortical GM structures. All structures were then transformed to each patient space in order to measure the SI in each region. The cerebellar peduncles (CP) and semi-oval (SO) white matter were then manually delineated and used as reference to calculate SI ratios in the DN and subcortical GM structures. A linear mixed-effect model was finally applied to longitudinally analyze SI variations. RESULTS: The SI measurements performed in all structures showed no significant increases with the cumulative GBCA administration. CONCLUSION: This study showed no significant SI increases within the DN and subcortical GM structures of longitudinally followed MS patients even with the cumulative administration of the macrocyclic GBCA gadoterate meglumine.

Asunto(s)

Esclerosis Múltiple , Compuestos Organometálicos , Núcleos Cerebelosos , Medios de Contraste , Gadolinio DTPA , Sustancia Gris , Humanos , Imagen por Resonancia Magnética , Meglumina , Estudios Retrospectivos

RESUMEN

Traumatic brain injury (TBI) may increase susceptibility to neurodegenerative diseases later in life. One neurobiological parallel between chronic TBI and neurodegeneration may be accelerated aging and the nature of atrophy across subcortical gray matter structures. The main aim of the present investigation is to evaluate and rank the degree that subcortical gray matter atrophy differentiates chronic moderate-severe TBI from non-TBI participants by evaluating morphometric differences between groups. Forty individuals with moderate-severe chronic TBI (9.23 yrs from injury) and 33 healthy controls (HC) underwent high resolution 3D T1-weighted structural magnetic resonance imaging. Whole brain volume was classified into white matter, cortical and subcortical gray matter structures with hippocampi and thalami further segmented into subfields and nuclei, respectively. Extensive atrophy was observed across nearly all brain regions for chronic TBI participants. A series of multivariate logistic regression models identified subcortical gray matter structures of the hippocampus and thalamus as the most sensitive to differentiating chronic TBI from non-TBI participants (McFadden R2 = .36, p < .001). Further analyses revealed the pattern of hippocampal atrophy to be global, occurring across nearly all subfields. The pattern of thalamic atrophy appeared to be much more selective and non-uniform, with largest between-group differences evident for nuclei bordering the ventricles. Subcortical gray matter was negatively correlated with time since injury (r = -.31, p = .054), while white matter and cortical gray matter were not. Cognitive ability was lower in the chronic TBI group (Cohen's d = .97, p = .003) and correlated with subcortical structures including the pallidum (r2 = .23, p = .038), thalamus (r2 = .36, p = .007) and ventral diencephalon (r2 = .23, p = .036). These data may support an accelerated aging hypothesis in chronic moderate-severe TBI that coincides with a similar neuropathological profile found in neurodegenerative diseases.

Asunto(s)

Lesiones Traumáticas del Encéfalo , Sustancia Gris , Atrofia/patología , Encéfalo/patología , Lesiones Traumáticas del Encéfalo/diagnóstico por imagen , Lesiones Traumáticas del Encéfalo/patología , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Hipocampo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Núcleos Talámicos

RESUMEN

Brain imaging-derived structural correlates of alcohol involvement have largely been speculated to arise as a consequence of alcohol exposure. However, they may also reflect predispositional risk. In substance naïve children of European ancestry who completed the baseline session of the Adolescent Brain Cognitive Development (ABCD) Study (n = 3013), mixed-effects models estimated whether polygenic risk scores (PRS) for problematic alcohol use (PAU-PRS) and drinks per week (DPW-PRS) are associated with magnetic resonance imaging-derived brain structure phenotypes (i.e., total and regional: cortical thickness, surface area and volume; subcortical volume; white matter volume, fractional anisotropy, mean diffusivity). Follow-up analyses evaluated whether any identified regions were also associated with polygenic risk among substance naïve children of African ancestry (n = 898). After adjustment for multiple testing correction, polygenic risk for PAU was associated with lower volume of the left frontal pole and greater cortical thickness of the right supramarginal gyrus (|ßs| > 0.009; ps < 0.001; psfdr < 0.046; r2 s < 0.004). PAU PRS and DPW PRS showed nominally significant associations with a host of other regional brain structure phenotypes (e.g., insula surface area and volume). None of these regions showed any, even nominal association among children of African ancestry. Genomic liability to alcohol involvement may manifest as variability in brain structure during middle childhood prior to alcohol use initiation. Broadly, alcohol-related variability in brain morphometry may partially reflect predisposing genomic influence. Larger discovery genome-wide association studies and target samples of diverse ancestries are needed to determine whether observed associations may generalize across ancestral origins.

RESUMEN

Insufficient or lack of response to antipsychotic medications in some patients with schizophrenia is a major challenge in psychiatry, but the underlying mechanisms remain unclear. Two seemingly unrelated observations, cerebral white matter and N-methyl-D-aspartate receptor (NMDAR) hypofunction, have been linked to treatment-resistant schizophrenia (TRS). As NMDARs are critical to axonal myelination and signal transduction, we hypothesized that NMDAR antibody (Ab), when present in schizophrenia, may impair NMDAR functions and white matter microstructures, contributing to TRS. In this study, 50 patients with TRS, 45 patients with nontreatment-resistant schizophrenia (NTRS), 53 patients with schizophrenia at treatment initiation schizophrenia (TIS), and 90 healthy controls were enrolled. Serum NMDAR Ab levels and white matter diffusion tensor imaging fractional anisotropy (FA) were assessed. The white matter specificity effects by NMDAR Ab were assessed by comparing with effects on cortical and subcortical gray matter. Serum NMDAR Ab levels of the TRS were significantly higher than those of the NTRS (P = .035). In patients with TRS, higher NMDAR Ab levels were significantly associated with reduced whole-brain average FA (r = -.37; P = .026), with the strongest effect at the genu of corpus callosum (r = -.50; P = .0021, significant after correction for multiple comparisons). Conversely, there was no significant correlation between whole-brain or regional cortical thickness or any subcortical gray matter structural volume and NMDAR Ab levels in TRS. Our finding highlights a potential NMDAR mechanism on white matter microstructure impairment in schizophrenia that may contribute to their treatment resistance to antipsychotic medications.

Asunto(s)

Autoanticuerpos/sangre , Corteza Cerebral/patología , Cuerpo Calloso/patología , Sustancia Gris/patología , Receptores de N-Metil-D-Aspartato/inmunología , Esquizofrenia Resistente al Tratamiento/inmunología , Esquizofrenia Resistente al Tratamiento/patología , Sustancia Blanca/patología , Adulto , Corteza Cerebral/diagnóstico por imagen , Cuerpo Calloso/diagnóstico por imagen , Imagen de Difusión Tensora , Femenino , Sustancia Gris/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Esquizofrenia Resistente al Tratamiento/sangre , Esquizofrenia Resistente al Tratamiento/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Adulto Joven

RESUMEN

Subcortical aphasia develops as a result of damage to subcortical brain areas without loss of cortical functions. Although earlier voxel-based lesion-symptom mapping (VLSM) studies have shown possible neural correlates for aphasia, it remains to be clarified which brain regions are associated with subcortical aphasia. The aim of this study was to investigate the neural substrates associated with subcortical aphasia in patients with stroke using VLSM and atlas-based analyses to explore the involvement of white matter tracts and subcortical structures. Fifty patients with subacute subcortical stroke without cortical involvement were retrospectively enrolled: 24 with and 26 without aphasia. We performed VLSM and atlas-based analyses of the patients' fluid-attenuated inversion recovery images and found that the left perisylvian white matter, left fronto-occipital fasciculus, uncinate fasciculus, and forceps minor were significantly more greatly affected in the aphasia than in the non-aphasia group. The left anterior thalamic radiation, cingulum (cingulate gyrus), and superior longitudinal fasciculus also showed higher involvement in this group (marginal significance). Among the subcortical regions, the left caudate and putamen were more greatly involved in the aphasia group. Our findings confirm language processing as one of the integrated sensory-motor processes that occur in the region around the left sylvian fissure. Our atlas-based analysis approach can be used to complement VLSM analyses.

Asunto(s)

Afasia , Accidente Cerebrovascular , Sustancia Blanca , Afasia/diagnóstico por imagen , Afasia/etiología , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética , Estudios Retrospectivos , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen

RESUMEN

Thirty million people are infected with human immunodeficiency virus (HIV) worldwide, and HIV-associated neurocognitive disorder (HAND) is one of the most common comorbidities of HIV. However, the effect of HIV on the brain has not been fully investigated. This article aimed to review the changes to the brain due to HIV in terms of atrophy, diffusion changes, and hyperintensities. Studies have observed significant atrophy in subcortical gray matter, as well as in cortical white and gray matter. Moreover, the ventricles enlarge, and the sulci widen. Although HIV causes changes to the white and gray matter of the brain, few diffusion tensor imaging studies have investigated the changes to gray matter integrity. White and gray matter hyperintensities have frequently been observed in HIV-positive individuals, with the subcortical gray matter (caudate nucleus and putamen) and periventricular white matter frequently affected. In conclusion, subcortical gray matter is the first brain region to be affected and is affected most severely. Additionally, this review highlights the gaps in the literature, since the effect of HIV on the brain is not fully known. Future studies should continue to investigate the effect of HIV on the brain in different stages of the disease, and alternate therapies should be developed since highly active antiretroviral therapy is currently ineffective at treating HAND.

Asunto(s)

Encéfalo/virología , Infecciones por VIH/virología , Atrofia/diagnóstico por imagen , Atrofia/virología , Encéfalo/diagnóstico por imagen , Imagen de Difusión Tensora , VIH , Infecciones por VIH/diagnóstico por imagen , Humanos

RESUMEN

OBJECTIVE: Functional and structural brain alterations of cognitively normal Parkinson's disease (PD-CN) and Parkinson's disease mild cognitive impairment (PD-MCI) patients were investigated using event-related potentials (ERP) P300 and volumetric magnetic resonance imaging (MRI) parameters. METHODS: Twenty three patients with PD-CN, 21 with PD-MCI, and 23 demographically-matched healthy controls were included. EEGs were recorded using a visual oddball task and mean amplitude and peak latency values of P300 were measured. Gray matter volumes (GMV) of thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala and nucleus accumbens were obtained using FMRIB Integrated Registration and Segmentation Tool. Correlations among P300, subcortical GMV and cognitive performances were assessed. RESULTS: PD-CN patients demonstrated reduced P300 amplitudes compared to healthy controls. PD-MCI patients had lower P300 amplitudes than both PD-CN patients and controls and reduced volumes of the putamen compared to controls. Both putamen volumes and P300 amplitudes showed moderate associations with executive functions. CONCLUSIONS: Our findings support that P300 amplitude may be a useful marker for the detection of preclinical changes before the appearance of cognitive and structural deterioration in PD, as shown by decreased frontal P300 amplitudes in PD-CN. The reduction further spread to centro-parietal areas in PD-MCI patients, which was accompanied by lower putamen volumes. SIGNIFICANCE: This study is the first to report on changes in ERP P300 amplitude and subcortical volume in well-matched samples of PD-CN, PD-MCI and healthy controls.

Asunto(s)

Disfunción Cognitiva/fisiopatología , Potenciales Relacionados con Evento P300 , Enfermedad de Parkinson/fisiopatología , Putamen/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Disfunción Cognitiva/complicaciones , Disfunción Cognitiva/diagnóstico por imagen , Femenino , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/diagnóstico por imagen , Putamen/fisiopatología

RESUMEN

PURPOSE: NODDI (Neurite Orientation Dispersion and Density Imaging) and DTI (Diffusion tensor imaging) may be useful in identifying abnormal regions in patients with MRI-negative refractory epilepsy. The aim of this study was to determine whether NODDI and DTI maps including neurite density (ND), orientation dispersion index (ODI), mean diffusivity (MD) and fractional anisotropy (FA) can detect structural abnormalities in cortical and subcortical gray matter (GM) in these patients. The correlation between these parameters and clinical characteristics of the disease was also investigated. METHODS: NODDI and DTI maps of 17 patients were obtained and checked visually. Region of interest (ROI) was drawn on suspected areas and contralateral regions in cortex. Contrast-to-noise ratio (CNR) was determined for each region. Furthermore volumetric data and mean values of ND, ODI, FA and MD of subcortical GM structures were calculated in both of the patients and controls. Finally, the correlations of these parameters in the subcortical with age of onset and duration of epilepsy were investigated. RESULTS: Cortical abnormalities on ODI images were observed in eight patients qualitatively. CNR of ODI was significantly greater than FA and MD. The subcortical changes including decrease of FA and ND and increase of ODI in left nucleus accumbens and increase of the volume in right amygdala were detected in the patients. CONCLUSIONS: The results revealed that NODDI can improve detection of microstructural changes in cortical and subcortical GM in patients with MRI negative epilepsy.

Asunto(s)

Epilepsia/diagnóstico por imagen , Epilepsia/patología , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Neuritas/patología , Adolescente , Adulto , Femenino , Humanos , Masculino , Tamaño de los Órganos , Adulto Joven

RESUMEN

Volumetric structural magnetic resonance imaging (MRI) is commonly used to determine the extent of neuronal loss in aging, indicated by cerebral atrophy. The brain, however, exhibits other biophysical characteristics such as mechanical properties, which can be quantified with magnetic resonance elastography (MRE). MRE is an emerging noninvasive imaging technique for measuring viscoelastic tissue properties, proven to be sensitive metrics of neural tissue integrity, as described by shear stiffness, µ and damping ratio, ξ parameters. The study objective was to evaluate global and regional MRE parameter differences between young (19-30 years, n = 12) and healthy older adults (66-73 years, n = 12) and to assess whether MRE measures provide additive value over volumetric magnetic resonance imaging measurements. We investigated the viscoelasticity of the global cerebrum and 6 regions of interest (ROIs) including the amygdala, hippocampus, caudate, pallidum, putamen, and thalamus. In older adults, we found a decrease in µ in all ROIs, except for the hippocampus, indicating widespread brain softening; an effect that remained significant after controlling for ROI volume. In contrast, the relative viscous-to-elastic behavior of the brain ξ did not differ between age groups, suggesting a preservation of the organization of the tissue microstructure. These data support the use of MRE as a novel imaging biomarker for characterizing age-related differences to neural tissue not captured by volumetric imaging alone.

Asunto(s)

Cerebro/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad/métodos , Elasticidad , Sustancia Gris/diagnóstico por imagen , Envejecimiento Saludable/patología , Envejecimiento Saludable/fisiología , Aumento de la Imagen/métodos , Adolescente , Adulto , Anciano , Cerebro/anatomía & histología , Cerebro/patología , Femenino , Sustancia Gris/anatomía & histología , Sustancia Gris/patología , Humanos , Masculino , Tamaño de los Órganos , Viscosidad , Adulto Joven

RESUMEN

Cognitive impairment is a significant clinical problem both in multiple sclerosis (MS) and systemic lupus erythematosus (SLE) patients. In MS cognitive dysfunction has been associated with brain atrophy and total demyelinating lesion volume. In SLE cognitive impairment is much less understood, and its link to structural brain damage remains to be established. The aim of this study was to identify the relationship between subcortical gray matter volume and cognitive impairment in MS and SLE. We recruited 37 MS and 38 SLE patients matched by age, disease duration and educational level. Patients underwent magnetic resonance imaging (MRI) and a battery of psychometric tests. Severity of cognitive impairment was similar in both cohorts despite larger white matter lesion load in MS patients. Psychometric scores were associated with global and subcortical gray matter atrophy measures and lesion load in MS, but not in SLE. In SLE, the lack of a relationship between cognitive impairment and structural damage, defined either as atrophy or white matter lesions, indicates a different causal mechanism of cognitive deficit.

Asunto(s)

Trastornos del Conocimiento/diagnóstico por imagen , Cognición , Sustancia Gris/diagnóstico por imagen , Lupus Eritematoso Sistémico/diagnóstico por imagen , Imagen por Resonancia Magnética , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagen , Adolescente , Adulto , Atrofia , Ganglios Basales/diagnóstico por imagen , Ganglios Basales/patología , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/patología , Trastornos del Conocimiento/psicología , Estudios Transversales , Femenino , Sustancia Gris/patología , Humanos , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/patología , Lupus Eritematoso Sistémico/psicología , Masculino , Persona de Mediana Edad , Esclerosis Múltiple Recurrente-Remitente/complicaciones , Esclerosis Múltiple Recurrente-Remitente/patología , Esclerosis Múltiple Recurrente-Remitente/psicología , Pruebas Neuropsicológicas , Valor Predictivo de las Pruebas , Estudios Prospectivos , Psicometría , Factores de Riesgo , Tálamo/diagnóstico por imagen , Tálamo/patología , Adulto Joven

RESUMEN

Magnetic resonance imaging of subcortical gray matter structures, which mediate behavior, cognition and the pathophysiology of several diseases, is crucial for establishing typical maturation patterns across the human lifespan. This single site study examines T1-weighted MPRAGE images of 3 healthy cohorts: (i) a cross-sectional cohort of 406 subjects aged 5-83 years; (ii) a longitudinal neurodevelopment cohort of 84 subjects scanned twice approximately 4 years apart, aged 5-27 years at first scan; and (iii) a longitudinal aging cohort of 55 subjects scanned twice approximately 3 years apart, aged 46-83 years at first scan. First scans from longitudinal subjects were included in the cross-sectional analysis. Age-dependent changes in thalamus, caudate, putamen, globus pallidus, nucleus accumbens, hippocampus, and amygdala volumes were tested with Poisson, quadratic, and linear models in the cross-sectional cohort, and quadratic and linear models in the longitudinal cohorts. Most deep gray matter structures best fit to Poisson regressions in the cross-sectional cohort and quadratic curves in the young longitudinal cohort, whereas the volume of all structures except the caudate and globus pallidus decreased linearly in the longitudinal aging cohort. Males had larger volumes than females for all subcortical structures, but sex differences in trajectories of change with age were not significant. Within subject analysis showed that 65%-80% of 13-17 year olds underwent a longitudinal decrease in volume between scans (∼4 years apart) for the putamen, globus pallidus, and hippocampus, suggesting unique developmental processes during adolescence. This lifespan study of healthy participants will form a basis for comparison to neurological and psychiatric disorders. Hum Brain Mapp 38:3771-3790, 2017. © 2017 Wiley Periodicals, Inc.

Asunto(s)

Envejecimiento/patología , Encéfalo/crecimiento & desarrollo , Encéfalo/patología , Sustancia Gris/crecimiento & desarrollo , Sustancia Gris/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Estudios Transversales , Sustancia Gris/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Modelos Lineales , Estudios Longitudinales , Imagen por Resonancia Magnética , Persona de Mediana Edad , Tamaño de los Órganos , Reproducibilidad de los Resultados , Caracteres Sexuales , Adulto Joven

RESUMEN

Accurate and robust segmentation of subcortical gray matter (SGM) nuclei is required in many neuroimaging applications. FMRIB's Integrated Registration and Segmentation Tool (FIRST) is one of the most popular software tools for automated subcortical segmentation based on T1-weighted (T1w) images. In this work, we demonstrate that FIRST tends to produce inaccurate SGM segmentation results in the case of abnormal brain anatomy, such as present in atrophied brains, due to a poor spatial match of the subcortical structures with the training data in the MNI space as well as due to insufficient contrast of SGM structures on T1w images. Consequently, such deviations from the average brain anatomy may introduce analysis bias in clinical studies, which may not always be obvious and potentially remain unidentified. To improve the segmentation of subcortical nuclei, we propose to use FIRST in combination with a special Hybrid image Contrast (HC) and Non-Linear (nl) registration module (HC-nlFIRST), where the hybrid image contrast is derived from T1w images and magnetic susceptibility maps to create subcortical contrast that is similar to that in the Montreal Neurological Institute (MNI) template. In our approach, a nonlinear registration replaces FIRST's default linear registration, yielding a more accurate alignment of the input data to the MNI template. We evaluated our method on 82 subjects with particularly abnormal brain anatomy, selected from a database of >2000 clinical cases. Qualitative and quantitative analyses revealed that HC-nlFIRST provides improved segmentation compared to the default FIRST method.

Asunto(s)

Mapeo Encefálico/métodos , Encéfalo/diagnóstico por imagen , Sustancia Gris/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Atrofia/patología , Encéfalo/patología , Femenino , Sustancia Gris/anatomía & histología , Voluntarios Sanos , Humanos , Masculino , Imagen Multimodal , Neuroimagen , Fantasmas de Imagen , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y Especificidad , Programas Informáticos , Adulto Joven

RESUMEN

OBJECTIVES: To characterize cognitive impairment in primary progressive multiple sclerosis (PPMS) and to correlate the pattern of cognitive deficits with brain magnetic resonance imaging (MRI) volumetric data. MATERIALS AND METHODS: In a multicenter cross-sectional study, we recruited consecutive patients with PPMS as well as age, sex, and education level-matched healthy controls (HC). All participants underwent neuropsychological (NP) assessment, and brain MRI was performed in patients with PPMS for analysis of lesion load, subcortical GM volumes, and regional cortical volumes. RESULTS: We recruited 55 patients with PPMS and 36 HC. Thirty-six patients were included in the MRI analysis. Patients with PPMS performed significantly worse than HC in all NP tests. Subcortical GM volume was significantly correlated with all NP tests, except for Stroop Test, with the largest effect for the thalamus (r=-.516 [BVMT-R DR, P=.016 FDR-corrected] to r=.664 [SDMT, P<.001 FDR-corrected]). In the stepwise linear regression model, thalamic volume was the only predictor of performance in all NP tests. CONCLUSION: Cognitive impairment is common in PPMS and affects all evaluated cognitive domains. Subcortical GM volume, particularly of the thalamus, is a strong predictor of cognitive performance, suggesting it has a central role in the pathophysiology of PPMS-related cognitive dysfunction.

Asunto(s)

Disfunción Cognitiva/diagnóstico por imagen , Disfunción Cognitiva/psicología , Imagen por Resonancia Magnética , Esclerosis Múltiple Crónica Progresiva/diagnóstico por imagen , Esclerosis Múltiple Crónica Progresiva/psicología , Adulto , Disfunción Cognitiva/epidemiología , Estudios Transversales , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple Crónica Progresiva/epidemiología , Pruebas Neuropsicológicas , Tálamo/diagnóstico por imagen

RESUMEN

PURPOSE: To investigate subcortical gray matter segmentation using transverse relaxation rate (R2 *) and quantitative susceptibility mapping (QSM) and apply it to voxel-based analysis in multiple sclerosis (MS). MATERIALS AND METHODS: Voxel-based variation in R2 * and QSM within deep gray matter was examined and compared to standard whole-structure analysis using 37 MS subjects and 37 matched controls. Deep gray matter nuclei (caudate, putamen, globus pallidus, and thalamus) were automatically segmented and morphed onto a custom atlas based on QSM and standard T1 -weighted images. Segmentation accuracy and scan-rescan reliability were tested. RESULTS: When considering only significant regions as returned by the multivariate voxel-based analysis, increased R2 * and QSM was found in MS subjects compared to controls in portions of all four nuclei studied (P < 0.002). For R2 *, regional analysis yielded at least 66-fold improved P-value significance in all nuclei over standard whole-structure analysis, while for QSM only thalamus benefited, with 5-fold improvement in significance. Improved segmentation over standard methods, particularly for globus pallidus (2.8 times higher Dice score), was achieved by incorporating high-contrast QSM into the atlas. Voxel-based reliability was highest for QSM (<1% variation). CONCLUSION: Automatic segmentation of iron-rich deep gray matter can be improved by incorporating QSM. Voxel-based evaluation yielded increased R2 * and QSM in MS subjects in all four nuclei studied with R2 *, benefiting the most from localized analysis over whole-structure measures.

Asunto(s)

Encéfalo/patología , Sustancia Gris/patología , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Esclerosis Múltiple/patología , Adulto , Algoritmos , Femenino , Humanos , Aumento de la Imagen/métodos , Masculino , Persona de Mediana Edad , Reconocimiento de Normas Patrones Automatizadas/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Técnica de Sustracción , Adulto Joven

RESUMEN

Quantitative susceptibility mapping (QSM) measures bulk susceptibilities in the brain, which can arise from many sources. In iron-rich subcortical gray matter (GM), non-heme iron is a dominant susceptibility source. We evaluated the use of QSM for iron mapping in subcortical GM by direct comparison to tissue iron staining. We performed in situ or in vivo QSM at 4.7 T combined with Perls' ferric iron staining on the corresponding extracted subcortical GM regions. This histochemical process enabled examination of ferric iron in complete slices that could be related to susceptibility measurements. Correlation analyses were performed on an individual-by-individual basis and high linear correlations between susceptibility and Perls' iron stain were found for the three multiple sclerosis (MS) subjects studied (R(2) = 0.75, 0.62, 0.86). In addition, high linear correlations between susceptibility and transverse relaxation rate (R2*) were found (R(2) = 0.88, 0.88, 0.87) which matched in vivo healthy subjects (R(2) = 0.87). This work validates the accuracy of QSM for brain iron mapping and also confirms ferric iron as the dominant susceptibility source in subcortical GM, by demonstrating high linear correlation of QSM to Perls' ferric iron staining.

Asunto(s)

Química Encefálica , Sustancia Gris/metabolismo , Hierro/metabolismo , Fenómenos Magnéticos , Imagen por Resonancia Magnética/métodos , Sustancia Gris/química , Sustancia Gris/patología , Humanos , Hierro/análisis , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/metabolismo , Esclerosis Múltiple/patología