During implantation of deep-brain stimulation (DBS) electrodes in the target structure, neurosurgeons and neurologists commonly observe a "microlesion effect" (MLE), which occurs well before initiating subthalamic DBS. This phenomenon typically leads to a transitory improvement of motor symptoms of patients suffering from Parkinson's disease (PD). Mechanisms behind MLE remain poorly understood. In this work, we exploited the notion of ranking to assess spontaneous brain activity in PD patients examined by resting-state functional magnetic resonance imaging in response to penetration of DBS electrodes in the subthalamic nucleus. In particular, we employed a hypothesis-free method, eigenvector centrality (EC), to reveal motor-communication-hubs of the highest rank and their reorganization following the surgery; providing a unique opportunity to evaluate the direct impact of disrupting the PD motor circuitry in vivo without prior assumptions. Penetration of electrodes was associated with increased EC of functional connectivity in the brainstem. Changes in connectivity were quantitatively related to motor improvement, which further emphasizes the clinical importance of the functional integrity of the brainstem. Surprisingly, MLE and DBS were associated with anatomically different EC maps despite their similar clinical benefit on motor functions. The DBS solely caused an increase in connectivity of the left premotor region suggesting separate pathophysiological mechanisms of both interventions. While the DBS acts at the cortical level suggesting compensatory activation of less affected motor regions, the MLE affects more fundamental circuitry as the dysfunctional brainstem predominates in the beginning of PD. These findings invigorate the overlooked brainstem perspective in the understanding of PD and support the current trend towards its early diagnosis.

• MeSH
• dospělí MeSH
• echoplanární zobrazování MeSH
• hluboká mozková stimulace škodlivé účinky   MeSH
• kyslík krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mapování mozku MeSH
• mozkový kmen krevní zásobení   fyziologie   MeSH
• nucleus subthalamicus krevní zásobení   patologie   MeSH
• odpočinek * MeSH
• Parkinsonova nemoc * patologie   patofyziologie   terapie   MeSH
• počítačové zpracování obrazu MeSH
• stupeň závažnosti nemoci MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The phenomenon of déjà vu (DV) has intrigued scientists for decades, yet its neurophysiological underpinnings remain elusive. Brain regions have been identified in which morphometry differs between healthy individuals according to the frequency of their DV experiences. This study built upon these findings by assessing if and how neural activity in these and other brain regions also differ with respect to DV experience. Resting-state fMRI was performed on 68 healthy volunteers, 44 of whom reported DV experiences (DV group) and 24 who did not (NDV group). Using multivariate analyses, we then assessed the (fractional) amplitude of low-frequency fluctuations (fALFF/ALFF), a metric that is believed to index brain tissue excitability, for five discrete frequency bands within sets of brain regions implicated in DV and those comprising the default mode network (DMN). Analyses revealed significantly lower values of fALFF/ALFF for specific frequency bands in the DV relative to the NDV group, particularly within mesiotemporal structures, bilateral putamina, right caudatum, bilateral superior frontal cortices, left lateral parietal cortex, dorsal and ventral medial prefrontal cortex, and the posterior cingulate cortex. The pattern of differences in fALFF/ALFF measures between the brains of individuals who have experienced DV and those who have not provides new neurophysiological insights into this phenomenon, including the potential role of the DMN. We suggest that the erroneous feeling of familiarity arises from a temporary disruption of cortico-subcortical circuitry together with the upregulation of cortical excitability.

• MeSH
• emoce MeSH
• lidé MeSH
• magnetická rezonanční tomografie * metody   MeSH
• mapování mozku metody   MeSH
• mozek diagnostické zobrazování   MeSH
• mozkové vlny * fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Účel studie: Cílem studie bylo srovnat postkontrastní zobrazení magnetickou rezonancí (KMR) a jednofotonovou emisní tomografii využívající 201Thallium chloridu (SPECT Tl) v hodnocení viability myokardu. Metodika: Do studie byli zařazení pacienti s chronickým koronárním onemocněním a systolickou dysfunkcí levé komory, u kterých byla plánována revaskularizace myokardu. Systolická dysfunkce levé komory byla definována ejekční frakcí (EF) ≤ 45 %. KMR byla provedena s využitím „Inversion Recovery Turbo FLASH (fast low-angle shot)“ sekvence. SPECT Tl zobrazení bylo provedeno čtyři hodiny po podání radiofarmaka. Výsledky: Do studie bylo zařazeno 40 nemocných. Kontrolní vyšetření EF po revaskularizaci bylo provedeno u 32 z nich. Souhlasné hodnocení viability mezi oběma metodami bylo pozorováno u 1065 (78,3 %) segmentů, což odpovídá pouze průměrné shodě (kappa 0,336). 96 SPECT Tl viabilních segmentů bylo popsáno jako neviabilní při KMR a 199 SPECT Tl neviabilních segmentů splňovalo kritéria viability dle KMR. U nemocných, kteří podstoupili kontrolní vyšetření po revaskularizaci EF stoupla o 5,5 % (z 33,6 na 39,2 %). Závislost mezi množstvím dysfunkční viabilní tkáně a změnou EF byla velmi slabá a statisticky nevýznamná u obou srovnávaných metod. Závěr: Při srovnání KMR a SPECT Tl v hodnocení viability myokardu nebyla pozorována dobrá shoda. Neprokázali jsme přínos viability určené oběma metodami pro predikci zlepšení systolické funkce levé komory po revaskularizaci.

Background: The aim of study was to compare contrast-enhanced magnetic resonance imaging (CE-MRI) to single-photon emission tomography using 201Thallium chloride (SPECT Tl) in the detection of myocardial viability. Methods: Patients with chronic coronary artery disease and ejection fraction (EF) ≤ 45 % were included. CE-MRI was performed using Inversion Recovery Turbo FLASH (fast low-angle shot) sequence and 4-hours rest redistribution protocol was used for SPECT Tl. Results: Total number of 40 patients was included and 32 of them underwent follow-up exam after revascularization. The concordance in the viability assessment between the both methods was noted in 1 065 (78.3 %) segments, that resulted in moderate agreement only (kappa value 0.336). 96 SPECT Tl viable segments were non-viable on CE-MR and 199 SPECT Tl non-viable segments were viable according to CE-MR. The EF increased by 5.6 % (from 33.6 to 39.2) after revascularization, but the relation between the amount of dysfunctional viable myocardium and change of EF after revascularization was very weak and not statistically significant in both methods studied. Conclusion: Moderate agreement in the myocardial viability assessment between CE-MRI and SPECT Tl was observed. We did not prove the usefulness of any of the methods studied for the prediction of improvement of EF after revascularization.

• MeSH
• diagnostické techniky kardiovaskulární MeSH
• dospělí MeSH
• finanční podpora výzkumu jako téma MeSH
• ischemická choroba srdeční diagnóza   patologie   terapie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• prospektivní studie MeSH
• radioisotopová scintigrafie metody   MeSH
• revaskularizace myokardu MeSH
• syndrom omráčeného myokardu diagnóza   patologie   terapie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH

This review article aims to address the main features of breast cancer. Thus, the general aspects of this disease have been shown since the first evidence of breast cancer in the world until the numbers today. In this way, there are some ways to prevent breast cancer, such as the woman's lifestyle (healthy eating habits and physical activities) that helps to reduce the incidence of this anomaly. The first noticeable symptom of this anomaly is typically a lump that feels different from the rest of the breast tissue. More than 80% of breast cancer are discovered when the woman feels a lump being present and about 90% of the cases, the cancer is noticed by the woman herself. Currently, the most used method for the detection of cancer and other injuries is the Magnetic Resonance Imaging (MRI) technique. This technique has been shown to be very effective, however, for a better visualization of the images, Contrast Agents (CAs) are used, which are paramagnetic compounds capable of increasing the relaxation of the hydrogen atoms of the water molecules present in the body tissues. The most used CAs are Gd3+ complexes, although they are very efficient, they are toxic to the organism. Thus, new contrast agents have been studied to replace Gd3+ complexes; we can mention iron oxides as a promising substitute.

• MeSH
• kontrastní látky * MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• nádory prsu * diagnostické zobrazování   MeSH
• voda MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Recent studies have shown that drug-induced spatial alteration patterns in resting state functional activity as measured using magnetic resonance imaging (rsfMRI) are associated with the distribution of specific receptor systems targeted by respective compounds. Based on this approach, we introduce a toolbox (JuSpace) allowing for cross-modal correlation of MRI-based measures with nuclear imaging derived estimates covering various neurotransmitter systems including dopaminergic, serotonergic, noradrenergic, and GABAergic (gamma-aminobutric acid) neurotransmission. We apply JuSpace to two datasets covering Parkinson's disease patients (PD) and risperidone-induced changes in rsfMRI and cerebral blood flow (CBF). Consistently with the predominant neurodegeneration of dopaminergic and serotonergic system in PD, we find significant spatial associations between rsfMRI activity alterations in PD and dopaminergic (D2) and serotonergic systems (5-HT1b). Risperidone induced CBF alterations were correlated with its main targets in serotonergic and dopaminergic systems. JuSpace provides a biologically meaningful framework for linking neuroimaging to underlying neurotransmitter information.

• MeSH
• jednofotonová emisní výpočetní tomografie * MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mozkový krevní oběh účinky léků   MeSH
• nervový přenos * fyziologie   MeSH
• neurotransmiterové látky farmakologie   MeSH
• neurozobrazování metody   MeSH
• Parkinsonova nemoc diagnostické zobrazování   metabolismus   MeSH
• pozitronová emisní tomografie * MeSH
• receptory neurotransmiterů * účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Historically, magnetic resonance imaging (MRI) has contributed little to the study of Parkinson's disease (PD), but modern MRI approaches have unveiled several complementary markers that are useful for research and clinical applications. Iron- and neuromelanin-sensitive MRI detect qualitative changes in the substantia nigra. Quantitative MRI markers can be derived from diffusion weighted and iron-sensitive imaging or volumetry. Functional brain alterations at rest or during task performance have been captured with functional and arterial spin labeling perfusion MRI. These markers are useful for the diagnosis of PD and atypical parkinsonism, to track disease progression from the premotor stages of these diseases and to better understand the neurobiological basis of clinical deficits. A current research goal using MRI is to generate time-dependent models of the evolution of PD biomarkers that can help understand neurodegeneration and provide reliable markers for therapeutic trials. This article reviews recent advances in MRI biomarker research at high-field (3T) and ultra high field-imaging (7T) in PD and atypical parkinsonism. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

• MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• parkinsonské poruchy diagnostické zobrazování   MeSH
• zobrazování trojrozměrné * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Acquiring pulmonary circulation parameters as a potential marker of cardiopulmonary function is not new. Methods to obtain these parameters have been developed over time, with the latest being first-pass perfusion sequences in cardiovascular magnetic resonance (CMR). Even though more data on these parameters has been recently published, different nomenclature and acquisition methods are used across studies; some works even reported conflicting data. The most commonly used circulation parameters obtained using CMR include pulmonary transit time (PTT) and pulmonary transit beats (PTB). PTT is the time needed for a contrast agent (typically gadolinium-based) to circulate from the right ventricle (RV) to the left ventricle (LV). PTB is the number of cardiac cycles the process takes. Some authors also include corrected heart rate (HR) versions along with standard PTT. Besides other methods, CMR offers an option to assess stress circulation parameters, but data are minimal. This review aims to summarize the up-to-date findings and provide an overview of the latest progress on this promising, dynamically evolving topic.

• MeSH
• kontrastní látky MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie * metody   MeSH
• plicní oběh fyziologie   MeSH
• prediktivní hodnota testů MeSH
• srdce * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

While there is good evidence for altered resting-state networks, particularly the default mode network (DMN), in both Alzheimer's disease (AD) and amnestic mild cognitive impairment preceding AD, there are rather conflicting data on changes in the DMN in Parkinson's disease (PD) and PD with cognitive impairment. This paper will focus on DMN study results, particularly in PD, as assessed by functional MRI.

• MeSH
• Alzheimerova nemoc patofyziologie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mozek patofyziologie   MeSH
• nervové dráhy fyziologie   MeSH
• odpočinek fyziologie   MeSH
• Parkinsonova nemoc patofyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

OBJECTIVES: In this study, we aimed to investigate whether peroneal electrical Transcutaneous Neuromodulation invented for overactive bladder (OAB) treatment elicits activation in brain regions involved in neural regulation of the lower urinary tract. MATERIALS AND METHODS: Among 22 enrolled healthy female volunteers, 13 were eligible for the final analysis. Functional magnetic resonance imaging (fMRI) (Siemens VIDA 3T; Erlangen, Germany) was used to compare the brain region activation elicited by peroneal electrical Transcutaneous Neuromodulation with the activation elicited by sham stimulation. Each subject underwent brain fMRI recording during eight 30-second periods of rest, alternating with 30-second periods of passive feet movement using the sham device, mimicking the motor response to peroneal nerve stimulation. Subsequently, fMRI recording was performed during the analogic "off-on" stimulation paradigm using peroneal electrical transcutaneous neuromodulation. Magnetic resonance imaging data acquired during both paradigms were compared using individual and group statistics. RESULTS: During both peroneal electrical Transcutaneous Neuromodulation and sham feet movements, we observed activation of the primary motor cortex and supplementary motor area, corresponding to the cortical projection of lower limb movement. During peroneal electrical Transcutaneous Neuromodulation, we observed significant activations in the brain stem, cerebellum, cingulate gyrus, putamen, operculum, and anterior insula, which were not observed during the sham feet movement. CONCLUSIONS: Our study provides evidence that peroneal electrical Transcutaneous Neuromodulation elicits activation of brain structures that have been previously implicated in the perception of bladder fullness and that play a role in the ability to cope with urinary urgency. Our data suggest that neuromodulation at the level of supraspinal control of the lower urinary tract may contribute to the treatment effect of peroneal electrical Transcutaneous Neuromodulation in patients with OAB.

• MeSH
• hyperaktivní močový měchýř * diagnostické zobrazování   terapie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• močový měchýř MeSH
• mozek fyziologie   MeSH
• transkutánní elektrická neurostimulace * metody   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Functional connectivity (FC) analysis is a prominent approach to analyzing fMRI data, especially acquired under the resting state condition. The commonly used linear correlation FC measure bears an implicit assumption of Gaussianity of the dependence structure. If only the marginals, but not all the bivariate distributions are Gaussian, linear correlation consistently underestimates the strength of the dependence. To assess the suitability of linear correlation and the general potential of nonlinear FC measures, we present a framework for testing and estimating the deviation from Gaussianity by means of comparing mutual information in the data and its Gaussianized counterpart. We apply this method to 24 sessions of human resting state fMRI. For each session, matrix of connectivities between 90 anatomical parcel time series is computed using mutual information and compared to results from its multivariate Gaussian surrogate that conserves the correlations but cancels any nonlinearity. While the group-level tests confirmed non-Gaussianity in the FC, the quantitative assessment revealed that the portion of mutual information neglected by linear correlation is relatively minor-on average only about 5% of the mutual information already captured by the linear correlation. The marginality of the non-Gaussianity was confirmed in comparisons using clustering of the parcels-the disagreement between clustering obtained from mutual information and linear correlation was attributable to random error. We conclude that for this type of data, practical relevance of nonlinear methods trying to improve over linear correlation might be limited by the fact that the data are indeed almost Gaussian.

• MeSH
• algoritmy MeSH
• dospělí MeSH
• Fourierova analýza MeSH
• kyslík krev   MeSH
• lidé MeSH
• lineární modely MeSH
• magnetická rezonanční tomografie MeSH
• mladý dospělý MeSH
• nervové dráhy fyziologie   MeSH
• normální rozdělení MeSH
• odpočinek fyziologie   MeSH
• shluková analýza MeSH
• software MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH