20 research outputs found
White-matter microstructural changes in episodic menstrual migraine compared with hormonal controls
Question: Do patients with episodic menstrual migraine exhibit white-matter microstructural changes? Methods: 14 women with episodic menstrual migraine (35±8yrs) were assessed during interictal phase together with 11 healthy women (29±10yrs) during a matching phase of their menstrual cycle (post-ovulation). 2D-EPI multi-shell DWI data were acquired on a 3T Siemens Vida (64-ch coil) and preprocessed using DESIGNER [1]. Diffusion tensor / kurtosis imaging (DTI/DKI) parameter maps were estimated and skeletonised [2] and histogram-metrics were computed for each subject: median, peak height, width, and value. Results: Voxelwise statistical analysis [3] revealed multiple whitematter regions with lower MD and AD in patients, with no differences in FA and RD. Interestingly, migraineurs showed increased MK, AK and RK. Moreover, significant groups differences (Mann- Whitney test with Bonferroni correction) were found in histogram-metrics MD peak value, AD median and peak height and AK median. Median AK was positively associated (Spearman correlation) with disease duration but not with attack frequency and pain intensity. Conclusion: Our findings extended previous reports of whitematter microstructural changes in migraineurs across multiple brain regions [4, 5]. DKI histogram-metrics showed potential as disease biomarkers.info:eu-repo/semantics/publishedVersio
Cognition in menstrually related migraine: neural correlates of working memory along the cycle
QUESTION: Hormones play a preponderant role in triggering migraine attacks, with women having higher prevalence and severity of migraine due to their influence along the reproductive cycle1. The preictal, ictal and postictal phases tend to include cognitive executive difficulties along with the rest of the attack symptoms2. Fluctuations in neural sensitivity observed in migraine could underlie such difficulties3. On the other hand, functional and structural changes in brain structures related to cognitive processes along the menstrual cycle have also been documented4. We aim to use functional Magnetic Resonance Imaging (fMRI) to evaluate working memory at different stages of the migraine cycle and compare to a non-migraine population while controlling for their menstrual phases. METHODS: A clinical sample of 15 women suffering from episodic migraine with menstrual-related attacks were recruited. They underwent fMRI sessions with a verbal N-back task in different phases of the migraine cycle, namely, preictal, ictal, postictal and interictal phase. 15 nonmigraine controls matched for gender and age were assessed during premenstrual and post ovulation phase. A neuropsychological battery and questionnaires quantifying clinical symptoms and attack description at the time of the exam were also applied. RESULTS: We report results for 70 sessions of acquisition in whole brain group analysis using a cluster threshold of z > 2.3. We observed left orbital prefrontal areas with significantly higher activation during preictal (z =3.44), ictal (z=3.49) and interictal (z=3.3) phases compared to postictal phase. CONCLUSIONS: The brain activation observed in prefrontal regions during the migraine attack phases could be related to cognitive inhibition while performing a working memory task.info:eu-repo/semantics/publishedVersio
Dynamic functional connectivity in migraine during the interictal phase: a resting-state fMRI study
Question: Migraine is a cyclic and complex disorder, characterized by attacks of headache, sensory and cognitive disturbances1. Thalamocortical connectivity in migraine has been found to be transiently abnormal2. Our aim was to assess if the dynamical properties of the migraine brain are affected during the interictal phase. Methods: Resting-state functional MRI data was collected from 14 menstrual migraine patients without aura (interictal phase) and 12 healthy controls (menstrual post-ovulation phase). fMRI data processing included3: motion and distortion correction, temporal highpass filter, regression of motion and physiological confounds, spatial smoothing, and parcellation with the Desikan atlas. Dynamic functional connectivity (dFC) between regions was computed using phase coherence, and recurrent dFC states were identified by kmeans clustering (k ranging between 3 and 15) of the leading eigenvectors of dFC in each time point4. Permutation tests were performed to evaluate statistically significant differences between patients and controls in the probability of occurrence and the mean lifetime of the dFC states. Results: Similar dFC states were found consistently across different numbers of clusters, k, which resembled the canonical resting-state networks as expected. Compared to healthy controls, migraine patients show a significantly lower mean lifetime in one dFC state, when grouping in 4, 5 and 6 clusters. No differences were found for the probability of occurrence. Conclusions: Migraine may be linked to a disruption of brain networks dynamics. This emphasizes the need to adopt time-resolved methods, in addition to static, to study functional connectivity, to better understand the mechanisms of migraine. Our next step will be to assess the dynamics of the migraine brain throughout the migraine cycle.info:eu-repo/semantics/publishedVersio
Impact of susceptibility-induced distortion correction on perfusion imaging by pCASL with a segmented 3D GRASE readout
Purpose: The consensus for the clinical implementation of arterial spin labeling (ASL) perfusion imaging recommends a segmented 3D Gradient and Spin-Echo (GRASE) readout for optimal signal-to-noise-ratio (SNR). The correction of the associated susceptibility-induced geometric distortions has been shown to improve diagnostic precision, but its impact on ASL data has not been systematically assessed and it is not consistently part of pre-processing pipelines. Here, we investigate the effects of susceptibility-induced distortion correction on perfusion imaging by pseudo-continuous ASL (pCASL) with a segmented 3D GRASE readout. Methods: Data acquired from 28 women using pCASL with 3D GRASE at 3T was analyzed using three pre-processing options: without distortion correction, with distortion correction, and with spatial smoothing (without distortion correction) matched to control for blurring effects induced by distortion correction. Maps of temporal SNR (tSNR) and relative perfusion were analyzed in eight regions-of-interest (ROIs) across the brain. Results: Distortion correction significantly affected tSNR and relative perfusion across the brain. Increases in tSNR were like those produced by matched spatial smoothing in most ROIs, indicating that they were likely due to blurring effects. However, that was not the case in the frontal and temporal lobes, where we also found increased relative perfusion with distortion correction even compared with matched spatial smoothing. These effects were found in both controls and patients, with no interactions with the participant group. Conclusion: Correction of susceptibility-induced distortions significantly impacts ASL perfusion imaging using a segmented 3D GRASE readout, and this step should therefore be considered in ASL pre-processing pipelines. This is of special importance in clinical studies, reporting perfusion across ROIs defined on relatively undistorted images and when conducting group analyses requiring the alignment of images across different subjects.info:eu-repo/semantics/publishedVersio
O Impacto do Estádio no Consumo do Torcedor: como a Frequência no Estádio Impulsiona a Demanda por Produtos dos Clubes
The aim of this study is to investigate the relationship between the presence of supporter in the stadium, which demonstrates the supporter’s involvement with his soccer club, and its influence on the purchase of official products of the 12 largest Brazilian brands of soccer clubs. In this research, it was collected information from 1,296 supporters who responded to a questionnaire with 22 questions. It was defined as involvement with their soccer club the frequency this supporter goes to the stadium. In order to determine the consumption relationship it were used variables such as frequency of purchase of official products, the annual amount spent on such products, favorite venue to purchase and assortment of the products mix. For the supporters buying preferences analysis, it was applied the technique of correspondence analysis (Anacor). As a result, we can point out that the supporters’ loyalty, driven by the relationship marketing, is one of the catalysts for increasing the soccer clubs revenue, since the higher the products and average tickets purchase frequency, the more this frequency is associated with a higher number of attendance to the stadium, as well as the variety in the mix of products acquired by the supporter. In this sense, the work points to the importance of building a long term relationship which goes beyond the emotional bond with the club, reaching the brand products consumption.O objetivo deste estudo é investigar a relação existente entre a presença do torcedor no estádio, que demonstra o envolvimento do torcedor com seu clube de futebol, e sua influência na compra de produtos oficiais das 12 maiores marcas brasileiras de clubes de futebol. Nesta pesquisa, coletaram-se informações de 1.296 torcedores que responderam a um questionário com 22 perguntas. Definiu-se como envolvimento com seu clube de futebol a frequência de ida ao estádio. Para determinar a relação de consumo, foram utilizadas variáveis como frequência de compra de produtos oficiais, valor anual gasto com tais produtos, local preferido para realização de compras e sortimento do mix de produto. Para a análise das preferências de compra do torcedor, foi aplicada a técnica de análise de correspondência (Anacor). Como resultado, pode-se apontar que a fidelização do torcedor, impulsionada pelo marketing de relacionamento, é um dos catalisadores para aumentar as receitas dos clubes de futebol, já que maiores frequências de compra e tíquetes médios estão associadas a um número maior de idas ao estádio, assim como à variedade do mix de produtos adquiridos pelo torcedor. Nesse sentido, o trabalho aponta para a importância de construir uma relação de longo prazo que vá além do vínculo emocional com o clube, chegando até ao consumo dos produtos da marca
O papel da colangiografia por ressonância magnética na avaliação da anatomia biliar em doadores de transplante hepático intervivos
Long-term effects of the testicular torsion on the spermatogenesis of the contralateral testis and the preventive value of the twisted testis orchiepididymectomy
Brain perfusion imaging by multi‐delay arterial spin labeling: Impact of modeling dispersion and interaction with denoising strategies and pathology
Purpose: Arterial spin labeling (ASL) acquisitions at multiple post-labeling delays may provide more accurate quantification of cerebral blood flow (CBF), by fitting appropriate kinetic models and simultaneously estimating relevant parameters such as the arterial transit time (ATT) and arterial cerebral blood volume (aCBV). We evaluate the effects of denoising strategies on model fitting and parameter estimation when accounting for the dispersion of the label bolus through the vasculature in cerebrovascular disease. Methods: We analyzed multi-delay ASL data from 17 cerebral small vessel disease patients (50 ± 9 y) and 13 healthy controls (52 ± 8 y), by fitting an extended kinetic model with or without bolus dispersion. We considered two denoising strategies: removal of structured noise sources by independent component analysis (ICA) of the control-label image timeseries; and averaging the repetitions of the control-label images prior to model fitting. Results: Modeling bolus dispersion improved estimation precision and impacted parameter values, but these effects strongly depended on whether repetitions were averaged before model fitting. In general, repetition averaging improved model fitting but adversely affected parameter values, particularly CBF and aCBV near arterial locations in patients. This suggests that using all repetitions allows better noise estimation at the earlier delays. In contrast, ICA denoising improved model fitting and estimation precision while leaving parameter values unaffected. Conclusion: Our results support the use of ICA denoising to improve model fitting to multi-delay ASL and suggest that using all control-label repetitions improves the estimation of macrovascular signal contributions and hence perfusion quantification near arterial locations. This is important when modeling flow dispersion in cerebrovascular pathology
A gestão ambiental em instituições de ensino superior: modelo para implantação em campus universitário
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Mitochondria-targeted antioxidant MitoQ ameliorates ischaemia-reperfusion injury in kidney transplantation models.
BACKGROUND: Ischaemia-reperfusion (IR) injury makes a major contribution to graft damage during kidney transplantation. Oxidative damage to mitochondria is an early event in IR injury. Therefore, the uptake, safety, and efficacy of the mitochondria-targeted antioxidant MitoQ were investigated in models of transplant IR injury. METHODS: MitoQ uptake by warm and cooled pairs of pig and declined human kidneys was measured when preserved in cold static storage or by hypothermic machine perfusion. Pairs of pigs' kidneys were exposed to defined periods of warm and cold ischaemia, flushed and stored at 4°C with or without MitoQ (50 nmol/l to 250 µmol/l), followed by reperfusion with oxygenated autologous blood in an ex vivo normothermic perfusion (EVNP). Pairs of declined human kidneys were flushed and stored with or without MitoQ (5-100 µmol/l) at 4°C for 6 h and underwent EVNP with ABO group-matched blood. RESULTS: Stable and concentration-dependent uptake of MitoQ was demonstrated for up to 24 h in pig and human kidneys. Total blood flow and urine output were significantly greater in pig kidneys treated with 50 µmol/l MitoQ compared with controls (P = 0.006 and P = 0.007 respectively). In proof-of-concept experiments, blood flow after 1 h of EVNP was significantly greater in human kidneys treated with 50 µmol/l MitoQ than in controls (P ≤ 0.001). Total urine output was numerically higher in the 50-µmol/l MitoQ group compared with the control, but the difference did not reach statistical significance (P = 0.054). CONCLUSION: Mitochondria-targeted antioxidant MitoQ can be administered to ischaemic kidneys simply and effectively during cold storage, and may improve outcomes after transplantation