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Purpose: To assess white matter changes after the first episode of schizophrenia by using fixel-based analysis (FBA). Methods: Diffusion weighted MR images were used to prospectively compare white matter microstructure between subjects after the first episode of schizophrenia (n = 16) and healthy controls (n = 22). The subjects were examined on a 3 Tesla MRI system equipped with a 64-channel head coil. FBA was performed using MRtrix software package (version 3.0.1). Results: A limited area of fibre density decrease was found in the anterior commissure. No fixels of fibre cross-section changes were found. For combined metric of fibre density and cross-section only one statistically significant fixel was found in the right frontal white matter. Conclusion: Using FBA, only a limited area of white matter microstructure corruption was found after the first episode of schizophrenia. Changes were located mainly in the anterior commissure. Compared to other published studies using FBA, the extent of changes is distinctly smaller which can be among other causes subjected to earlier stages of the illness of subjects included in this study. [ABSTRACT FROM AUTHOR]

Purpose: To asses cerebral cortical thickness and area changes in the earliest stage of schizophrenia. Methods: Magnetic resonance was used to prospectively compare cerebral cortex thickness and surface area between subjects after the first episode of schizophrenia (n = 15) and healthy controls (n = 19). The subjects were examined on a 3 Tesla MRI system equipped with a 64-channel head coil. Surface-based morphometry was performed on 3D T1- and T2-weighted data by using Freesurfer software package (ver. 7.1.0). Results: No statistically significantly different clusters of cerebral cortical surface / thickness were found between both groups of subjects. Conclusion: Contrary to the observations published by other authors including large multicentric studies, no statistically significant differences in cerebral cortical thickness or area were found in the earliest stage of schizophrenia. [ABSTRACT FROM AUTHOR]

Functional MR imaging (fMRI) belongs already longer than two decades between methods used for the investigation of the human brain but also for monitoring of functional changes related to pathological processes. This article shortly explains physical and physiological basis of fMRI methods and shows its advantages and limitations. Also, various types of fMRI data acquisition and evaluation are discussed including their benefits as well as restrictions. Using several examples, different approach to fMRI application is demonstrated beginning with traditional visualization of activated regions to more modern way of investigation of the brain network connectivity. This article is not a survey of published results in fMRI field but rather it should help to reader with orientation in entire issues concerning of fMRI including some new trends in this region. [ABSTRACT FROM AUTHOR]

Ectopic lipid accumulation in skeletal muscle is associated with insulin resistance. Telmisartan improves metabolic parameters in type 2 diabetic patients. The aim of our study was to evaluate the in vivo effect of telmisartan on intramyocellular lipid content (IMCL) in subjects with impaired fasting glucose (IFG) by magnetic resonance spectroscopy (MRS). We enrolled 10 subjects with IFG in a cross-over, placebo-controlled, randomized, double-blind trial, treated with 3 weeks of telmisartan (160 mg daily) or placebo. After completing each treatment, a hyperinsulinaemic euglycaemic clamp (1 mU/kg per min; 5 mmol/l; 120 min) to assess insulin action (metabolic clearance rate of glucose, MCR) and 1 H MRS of the m. tibialis anterior using a MR Scanner Siemens Vision operating at 1.5 T to evaluate IMCL content, were performed. Plasma adipokine levels were determined simultaneously. Telmisartan treatment resulted in a lower fasting plasma glucose (FPG) (p < 0.05), but insulin action was comparable to after placebo. Telmisartan did not affect IMCL content. After placebo, IMCL correlated negatively with total cholesterol (p < 0.001), MCR (p < 0.05) and adiponectin (p < 0.05) and positively with FPG (p < 0.05). After telmisartan treatment there was only a positive correlation between IMCL and TNFα (p < 0.05). IMCL content is related to parameters of glucose metabolism and insulin action in sedentary IFG subjects. A short telmisartan treatment did not affect the IMCL content despite its positive effect on FPG. The improvement in FPG was probably mediated through interference with other metabolic pathways. [ABSTRACT FROM AUTHOR]

Background: The main aim of the present study is to determine the role of metabolites observed using proton magnetic resonance spectroscopy (1H-MRS) in obsessive-compulsive disorder (OCD). As the literature describing biochemical changes in OCD yields conflicting results, we focused on accurate metabolite quantification of total N-acetyl aspartate (tNAA), total creatine (tCr), total choline-containing compounds (tCh), and myo-inositol (mI) in the anterior cingulate cortex (ACC) to capture the small metabolic changes between OCD patients and controls and between OCD patients with and without medication. Methods: In total 46 patients with OCD and 46 healthy controls (HC) matched for age and sex were included in the study. The severity of symptoms in the OCD was evaluated on the day of magnetic resonance imaging (MRI) using the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Subjects underwent 1H-MRS from the pregenual ACC (pgACC) region to calculate concentrations of tNAA, tCr, tCho, and mI. Twenty-eight OCD and 28 HC subjects were included in the statistical analysis. We compared differences between groups for all selected metabolites and in OCD patients we analyzed the relationship between metabolite levels and symptom severity, medication status, age, and the duration of illness. Results: Significant decreases in tCr (U = 253.00, p = 0.022) and mI (U = 197.00, p = 0.001) in the pgACC were observed in the OCD group. No statistically significant differences were found in tNAA and tCho levels; however, tCho revealed a trend towards lower concentrations in OCD patients (U = 278.00, p = 0.062). Metabolic concentrations showed no significant correlations with the age and duration of illness. The correlation statistics found a significant negative correlation between tCr levels and YBOCS compulsions subscale (cor = -0.380, p = 0.046). tCho and YBOCS compulsions subscale showed a trend towards a negative correlation (cor = -0.351, p = 0.067). Analysis of subgroups with or without medication showed no differences. Conclusions: Patients with OCD present metabolic disruption in the pgACC. The decrease in tCr shows an important relationship with OCD symptomatology. tCr as a marker of cerebral bioenergetics may also be considered as a biomarker of the severity of compulsions. The study failed to prove that metabolic changes correlate with the medication status or the duration of illness. It seems that a disruption in the balance between these metabolites and their transmission may play a role in the pathophysiology of OCD. [ABSTRACT FROM AUTHOR]

Purpose: To assess microstructural changes of the cerebral white matter in the earliest stage of schizophrenia. Methods: Magnetic resonance was used to prospectively compare fractional anisotropy of the white matter between subjects after the first episode of schizophrenia (n = 23) and healthy controls (n = 23). Diffusion tensor data obtained from multidirectional diffusion weighted sequence were analysed by using Tract-Based Spatial Statistics (TBSS). Results: Extensive areas of decreased fractional anisotropy (FA) were found in the white matter after the first episode of schizophrenia, affecting most of the white matter tracts. No areas of significantly increased FA were found when compared to the healthy control group. Conclusion: Extensive areas of microstructural alteration of the white matter are already present during the first episode of schizophrenia. [ABSTRACT FROM AUTHOR]

MR tractography (MRT) has become an important method for noninvasive visualization of white matter bundles and peripheral nerves using magnetic resonance imaging measurment of water molecule diffusion. This paper gives a short historical overview and implementation of the MRT into clinical practice in the institute IKEM. Furthermore, the paper gives a short overview of some MRT applications of brain and 3D MR neurography of peripheral nerves. The MR tractography and MR neurography may be used in the presurgical planning and post- -operative follow-up of the brain and peripheral nerves microstructural changes. [ABSTRACT FROM AUTHOR]

Despite the rising global burden of stroke and its socio-economic implications, the neuroimaging predictors of subsequent cognitive impairment are still poorly understood. We address this issue by studying the relationship of white matter integrity assessed within ten days after stroke and patients' cognitive status one year after the attack. Using diffusion-weighted imaging, we apply the Tract-Based Spatial Statistics analysis and construct individual structural connectivity matrices by employing deterministic tractography. We further quantify the graph-theoretical properties of individual networks. The Tract-Based Spatial Statistic did identify lower fractional anisotropy as a predictor of cognitive status, although this effect was mostly attributable to the age-related white matter integrity decline. We further observed the effect of age propagating into other levels of analysis. Specifically, in the structural connectivity approach we identified pairs of regions significantly correlated with clinical scales, namely memory, attention, and visuospatial functions. However, none of them persisted after the age correction. Finally, the graph-theoretical measures appeared to be more robust towards the effect of age, but still were not sensitive enough to capture a relationship with clinical scales. In conclusion, the effect of age is a dominant confounder especially in older cohorts, and unless appropriately addressed, may falsely drive the results of the predictive modelling. [ABSTRACT FROM AUTHOR]

We study patterns of partial synchronization in a network of FitzHugh–Nagumo oscillators with empirical structural connectivity measured in human subjects. We report the spontaneous occurrence of synchronization phenomena that closely resemble the ones seen during epileptic seizures in humans. In order to obtain deeper insights into the interplay between dynamics and network topology, we perform long-term simulations of oscillatory dynamics on different paradigmatic network structures: random networks, regular nonlocally coupled ring networks, ring networks with fractal connectivities, and small-world networks with various rewiring probability. Among these networks, a small-world network with intermediate rewiring probability best mimics the findings achieved with the simulations using the empirical structural connectivity. For the other network topologies, either no spontaneously occurring epileptic-seizure-related synchronization phenomena can be observed in the simulated dynamics, or the overall degree of synchronization remains high throughout the simulation. This indicates that a topology with some balance between regularity and randomness favors the self-initiation and self-termination of episodes of seizure-like strong synchronization. [ABSTRACT FROM AUTHOR]

Background. Augmented reality (AR) glasses with GPS navigation represent the rapidly evolving technology which spares (and externalizes) navigational capacities. Regarding the expected everyday usage of this device, its impact on neuroplastic brain changes and navigation abilities should be evaluated. Aims. This study aimed to assess possible changes in functional connectivity (FC) of hippocampus and other brain regions involved in spatial navigation. Methods. Thirty-three healthy participants completed two resting state functional magnetic resonance imaging (rsfMRI) measurements at the baseline and after 3 months. For this period, the experimental group (n = 17) has had used AR device (Vuzix M100) with incorporated GPS guidance system during navigation in real world. Participants from the control group (n = 16) have not used any GPS device while navigating during walking. The rsfMRI FC of right and left hippocampi was analyzed using a seed-driven approach. Virtual city task was used to test navigational abilities both before and after the usage of AR device. Results. We identified strong functional coupling of right and left hippocampi at the baseline (p < 0.05, FDR corrected). Mild changes in bilateral hippocampal FC (p < 0.05, FDR uncorrected) were observed in both assessed groups mainly between the bilateral hippocampi and between each hippocampus and temporal regions and cerebellum. However, the experimental group showed FC decrease after three months of using GPS navigation implemented in AR glasses in contrast to FC increase in the control group without such intervention. Importantly, no effect of intervention on navigational abilities was observed. Discussion. Our observation supports the assumption that externalization of spatial navigation to technological device (GPS in AR glasses) can decrease the functional coupling between hippocampus and associated brain regions. Considering some limitations of the present study, further studies should elucidate the mechanism of the observed changes and their impact on cognitive abilities. [ABSTRACT FROM AUTHOR]

The influence of iron deposits on T2 values and the content of metabolites in the brain of three patients with DNA proved pantothenate kinase-associated neurodegeneration (PKAN, formerly Hallervorden-Spatz syndrome) was studied. An eye-of-the-tiger sign, a typical MR finding for PKAN, was observed in two patients with the same mutation. A hypointensive lesion in a whole globus pallidus was observed in the third patient with the additional mutation. T2 values in the globus pallidus of the patients were about 40% shorter than in controls (71/48 ms in controls vs. patients), which corresponds to the increase of Fe concentration based on the ferritin basis from 17 mg for controls to 48 mg (100 g wet brain weight) in PKAN patients. 1H MR spectroscopy (MRS) has mainly been used to describe neuronal damage represented by decreased NAA (6.4 mmol vs. 9 mmol) and Cr/PCr (7.0 mmol vs. 9.8 mmol) concentrations in the basal ganglia region of the patient group to controls; MRS is much more case-sensitive and describes individual development of the disease as demonstrated in the difference between the spectra of typical PKAN patients (1, 2), and the patient (3) with atypical PKAN development. Any significant changes of metabolite concentration with the exception glutamine, glutamate and GABA were found in the white matter. [ABSTRACT FROM AUTHOR]