Segmented corpus callosum diffusivity correlates with the Expanded Disability Status Scale score in the early stages of relapsing-remitting multiple sclerosis

OBJECTIVE: The aim of this study was to characterize the microscopic damage to the corpus callosum in relapsing-remitting multiple sclerosis (RRMS) with diffusion tensor imaging and to investigate the correlation of this damage with disability. The diffusion tensor imaging parameters of fractional anisotropy and mean diffusivity provide information about the integrity of cell membranes, offering two more specific indices, namely the axial and radial diffusivities, which are useful for discriminating axon loss from demyelination. METHOD: Brain magnetic resonance imaging exams of 30 relapsing-remitting multiple sclerosis patients and 30 age- and sex-matched healthy controls were acquired in a 3T scanner. The axial diffusivities, radial diffusivities, fractional anisotropy, and mean diffusivity of five segments of the corpus callosum, correlated to the Expanded Disability Status Scale score, were obtained. RESULTS: All corpus callosum segments showed increased radial diffusivities and mean diffusivity, as well as decreased fractional anisotropy, in the relapsing-remitting multiple sclerosis group. The axial diffusivity was increased in the posterior midbody and splenium. The Expanded Disability Status Scale scores correlated more strongly with axial diffusivities and mean diffusivity, with an isolated correlation with radial diffusivities in the posterior midbody of the corpus callosum. There was no significant correlation with lesion loads. CONCLUSION: Neurological dysfunction in relapsing-remitting multiple sclerosis can be influenced by commissural disconnection, and the diffusion indices of diffusion tensor imaging are potential biomarkers of disability that can be assessed during follow-up

Age-effects in white matter using associated diffusion tensor imaging and magnetization transfer ratio during late childhood and early adolescence

In the last decade, several studies have described the typical brain white matter maturation in children and adolescents. Diffusion tensor imaging (DTI) is the most frequent MRI technique used to investigate the structural changes across development. However, few previous studies have used the magnetization transfer ratio (MTR), which gives a closer measure of myelin content. Here, we employed both techniques for the same sample of 176 typically developing children from 7 to 14 years of age. We investigated the associations between DTI parameters and MTR measure, to assess the myelination in the brain in development. Secondly, we investigated age-effects on DTI parameters (fractional anisotropy, axial, radial and mean diffusivities) and MTR. No significant correlations between MTR and DTI parameters were observed. In addition, a significant age-effect was detected for DTI data but was not visible for MTR data. Thereby, changes in white matter at this age might be primarily correlated with microstructural changes. (C) 2015 Elsevier Inc. All rights reserved.CAPES FoundationSao Paulo Research Foundation-FAPESPCNPq, BrazilUniv Fed Sao Paulo, Dept Psychiat, Rua Borges Lagoa 570,1 Andar, BR-04039032 Sao Paulo, BrazilFed Univ Sao Paulo UNIFESP, Interdisciplinary Lab Clin Neurosci LiNC, Sao Paulo, BrazilCNPq, Natl Inst Dev Psychiat Children & Adolescents, Sao Paulo, BrazilUniv Fed ABC, Ctr Math Computat & Cognit, Santo Andre, BrazilKings Coll London, Inst Psychiat Psychol & Neurosci, London WC2R 2LS, EnglandUniv Sao Paulo, Lab Magnet Resonance Neuroradiol, LIM 44, Inst & Dept Radiol, Sao Paulo, BrazilUniv Fed Rio Grande do Sul, Hosp Clin Porto Alegre, Dept Psychiat, BR-90046900 Porto Alegre, RS, BrazilUniv Fed Sao Paulo, Dept Psychiat, Rua Borges Lagoa 570,1 Andar, BR-04039032 Sao Paulo, BrazilFed Univ Sao Paulo UNIFESP, Interdisciplinary Lab Clin Neurosci LiNC, Sao Paulo, BrazilCAPES: 17930/12-0FAPESP: 2013/10498-6FAPESP: 2013/00506-1FAPESP: 2013/08531-5FAPESP: 2008/ 57896-8CNPq: 573974/2008-0CNPq: 442026/2014-5Web of Scienc

Mini-Mental State Examination and proton spectroscopy of the posterior cingulate in Alzheimer disease

Abstract To compare metabolite ratios in the posterior cingulate with the Mini-Mental State Examination (MMSE) test scores in patients with mild or moderate Alzheimer disease and in controls. Methods: We evaluated 29 patients with mild or moderate Alzheimer disease and 15 controls by proton spectroscopy with the voxel located in the posterior cingulate. The MMSE was applied to all patients and controls. The metabolic ratios: N-acetyl-aspartate/creatine (Naa/Cr), mio-inositol/creatine (mI/Cr) and mio-inositol/N-acetyl-aspartate (mI/Naa) were obtained and then post-processed using the MRUI software (magnetic resonance user interface). Results: Correlation between Naa/Cr and mI/Naa ratios in the posterior cingulate with the MMSE was observed, and a positive correlation with Naa/Cr and negative correlation with mI/Naa were seen. The mI/r ratio presented no correlation with MMSE scores. Conclusion: The positive correlation with Naa/Cr, and negative correlation with mI/Naa may corroborate that neuronal density/viability is associated to a higher MMSE score

Evaluation of multi-channel phase reconstruction methods for quantitative susceptibility mapping on postmortem human brain

Quantitative Susceptibility Mapping (QSM) is an established Magnetic Resonance Imaging (MRI) technique with high potential in brain iron studies associated to several neurodegenerative diseases. Unlike other MRI techniques, QSM relies on phase images to estimate tissue's relative susceptibility, therefore requiring a reliable phase data. Phase images from a multi-channel acquisition should be reconstructed in a proper way. On this work it was compared the performance of combination of phase matching algorithms (MCPC3D-S and VRC) and phase combination methods based on a complex weighted sum of phases, considering the magnitude at different powers (k = 0 to 4) as the weighting factor. These reconstruction methods were applied in two datasets: a simulated brain dataset for a 4-coil array and data of 22 postmortem subjects acquired at a 7T scanner using a 32 channels coil. For the simulated dataset, differences between the ground truth and the Root Mean Squared Error (RMSE) were evaluated. For both simulated and postmortem data, the mean (MS) and standard deviation (SD) of susceptibility values of five deep gray matter regions were calculated. For the postmortem subjects, MS and SD were statistically compared across all subjects. A qualitative analysis indicated no differences between methods, except for the Adaptive approach on postmortem data, which showed intense artifacts. In the 20% noise level case, the simulated data showed increased noise in central regions. Quantitative analysis showed that both MS and SD were not statistically different when comparing k=1 and k=2 on postmortem brain images, however visual inspection showed some boundaries artifacts on k=2. Furthermore, the RMSE decreased (on regions near the coils) and increased (on central regions and on overall QSM) with increasing k. In conclusion, for reconstruction of phase images from multiple coils with no reference available, alternative methods are needed. In this study it was found that overall, the phase combination with k=1 is preferred over other powers of k

Proton magnetic spectroscopy agreed better with magnetic resonance image to lateralization of epileptogenic zone than with surface electroencephalography

Objective To analyze the agreement rate of proton magnetic spectroscopy with magnetic resonance image (MRI) and surface electroence-phalography (EEG) in extratemporal neocortical epilepsies. Methods A cross-sectional study, type series of cases included 33 patients, age range 13–59 years old, of both gender, presenting structural alteration identified by MRI (75.8%) or by neurophysiologic techniques (72.7%). The variables were alterations of N-acetyl-aspartate/choline, N-acetyl-aspartate/creatine, choline/creatine, and N-acetyl-aspartate/cho-line+creatine coefficient of asymmetry. Results Agreement rates of lateralization by coefficient of asymmetry of NAA/Cho, NAA/Cr, Co/Cr, and NAA/Cho+Cr with MRI, independent of alteration of surface EEG, were equal to 93.3, 57.9, 15.4, and 93.3%, respectively, modifying to 100, 33.3, 0, and 100%, in 16 patients, with lateralization agreement of MRI and surface EEG. Conclusion Proton magnetic spectroscopy agreed better with MRI to lateralization of epileptogenic zone than with surface EEG

The impact of the CACNA1C risk allele on limbic structures and facial emotions recognition in bipolar disorder subjects and healthy controls

Introduction: Impairments in facial emotion recognition (PER) have been reported in bipolar disorder (BD) during all mood states. FER has been the focus of functional magnetic resonance imaging studies evaluating differential activation of limbic regions. Recently, the alpha 1-C subunit of the L-type voltage-gated calcium channel (CACNA1C) gene has been described as a risk gene for BD and its Met allele found to increase CACNA1C mRNA expression. In healthy controls, the CACNA1C risk (Met) allele has been reported to increase limbic system activation during emotional stimuli and also to impact on cognitive function. The aim of this study was to investigate the impact of CACNA1C genotype on FER scores and limbic system morphology in subjects with BD and healthy controls. Material and methods: Thirty-nine euthymic BD I subjects and 40 healthy controls were submitted to a PER recognition test battery and genotyped for CACNA1C. Subjects were also examined with a 3D 3-Tesla structural imaging protocol. Results: The CACNA1C risk allele for BD was associated to FER impairment in BD, while in controls nothing was observed. The CACNA1C genotype did not impact on amygdala or hippocampus volume neither in BD nor controls. Limitations: Sample size. Conclusion: The present findings suggest that a polymorphism in calcium channels interferes FER phenotype exclusively in BD and doesn't interfere on limbic structures morphology. (C) 2012 Elsevier B.V. All rights reserved.Sao Paulo Research Foundation (Fundo de Apoio a Pesquisa do Estado de Sao Paulo-FAPESP)Sao Paulo Research Foundation (Fundo de Apoio a Pesquisa do Estado de Sao PauloFAPESP

Carbohydrate supplementation increases intramyocellular lipid stores in elite runners

The objective was to determine the effects of carbohydrate (CHO) supplementation on exercise-induced hormone responses and post-training intramyocellular lipid stores (IMCL). Twenty-four elite male athletes (28.0 +/- 1.2 years) were randomized to receive CHO (maltodextrin solution) or zero energy placebo solution (control group). The high-intensity running protocol consisted of 10 x 800 m at 100% of the best 3000-m speed (Vm3 km) and 2 x 1000 m maximal bouts in the morning and a submaximal 10-km continuous easy running in the afternoon of day 9. IMCL concentrations were assessed by H-1-MRS before (-day 9) and after training (day 9) in soleus (SO) and tibialis anterior (TA) muscles. Blood hormones were also measured before, during, and post-exercise. The percent change (Delta%) in TA-IMCL was higher in the CHO group (47.9 +/- 24.5 IMCL/Cr) than in the control group (-1.7 +/- 13.1, respectively) (P=.04). Insulin concentrations were higher in the CHO group post-intermittent running compared to control (P=.02). Circulating levels of free fatty acids and GH were lower in the CHO group (P>.01). The decline in performance in the 2nd 1000-m bout was also attenuated in this group compared to control (P<.001 and P=.0035, respectively). The hormonal milieu (higher insulin and lower GH levels) in the CHO group, together with unchanged free fatty acid levels, probably contributed to the increased IMCL stores. This greater energy storage capacity may have improved post-exercise recovery and thus prevented performance deterioration. (C) 2012 Elsevier Inc. All rights reserved.FAPESPFAPES