Quantitative maps of rotating frame relaxation (RFR) time constants are sensitive and useful magnetic resonance imaging tools with which to evaluate tissue integrity in vivo. However, to date, only moderate image resolutions of 1.6 x 1.6 x 3.6 mm3 have been used for whole-brain coverage RFR mapping in humans at 3 T. For more precise morphometrical examinations, higher spatial resolutions are desirable. Towards achieving the long-term goal of increasing the spatial resolution of RFR mapping without increasing scan times, we explore the use of the recently introduced Transform domain NOise Reduction with DIstribution Corrected principal component analysis (T-NORDIC) algorithm for thermal noise reduction. RFR acquisitions at 3 T were obtained from eight healthy participants (seven males and one female) aged 52 ± 20 years, including adiabatic T1ρ, T2ρ, and nonadiabatic Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n = 4 (RAFF4) with both 1.6 x 1.6 x 3.6 mm3 and 1.25 x 1.25 x 2 mm3 image resolutions. We compared RFR values and their confidence intervals (CIs) obtained from fitting the denoised versus nondenoised images, at both voxel and regional levels separately for each resolution and RFR metric. The comparison of metrics obtained from denoised versus nondenoised images was performed with a two-sample paired t-test and statistical significance was set at p less than 0.05 after Bonferroni correction for multiple comparisons. The use of T-NORDIC on the RFR images prior to the fitting procedure decreases the uncertainty of parameter estimation (lower CIs) at both spatial resolutions. The effect was particularly prominent at high-spatial resolution for RAFF4. Moreover, T-NORDIC did not degrade map quality, and it had minimal impact on the RFR values. Denoising RFR images with T-NORDIC improves parameter estimation while preserving the image quality and accuracy of all RFR maps, ultimately enabling high-resolution RFR mapping in scan times that are suitable for clinical settings.

• Klíčová slova
• NORDIC, brain mapping, denoising, quantitative MRI, rotating frame relaxation,
• MeSH
• algoritmy MeSH
• analýza hlavních komponent MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie * metody   MeSH
• mapování mozku MeSH
• mozek * diagnostické zobrazování   MeSH
• poměr signál - šum * MeSH
• rotace MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

AIM: Despite the substantial progress that has been achieved in interventional cardiology and cardiac electrophysiology, endovascular intervention for the diagnosis and treatment of central nervous system (CNS) disorders such as stroke, epilepsy and CNS malignancy is still limited, particularly due to highly tortuous nature of the cerebral arterial and venous system. Existing interventional devices and techniques enable only limited and complicated access especially into intra-cerebral vessels. The aim of this study was to develop a micro-catheter magnetically-guided technology specifically designed for endovascular intervention and mapping in deep CNS vascular structures. METHODS: Mapping of electrical brain activity was performed via the venous system on an animal dog model with the support of the NIOBE II system. RESULTS: A novel micro-catheter specially designed for endovascular interventions in the CNS, with the support of the NIOBE II technology, was able to reach safely deep intra-cerebral venous structures and map the electrical activity there. Such structures are not currently accessible using standard catheters. CONCLUSION: This is the first study demonstrating successful use of a new micro-catheter in combination with NIOBE II technology for endovascular intervention in the brain.

• MeSH
• elektroencefalografie MeSH
• endovaskulární výkony přístrojové vybavení   metody   MeSH
• katétry MeSH
• magnety MeSH
• mapování mozku přístrojové vybavení   metody   MeSH
• mozková angiografie MeSH
• počítačové zpracování obrazu MeSH
• psi MeSH
• velký mozek krevní zásobení   diagnostické zobrazování   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

INTRODUCTION: Diagnostic cortical stimulation (CS) in intracranial electroencephalography (iEEG) is an established epilepsy presurgical assessment tool to delineate relevant brain functions and elicit habitual epileptic seizures. Currently, no consensus exists as to whether CS should be routinely performed in pediatric patients. A significant challenge is their limited ability to cooperate during the procedure or to describe non-observable seizure semiology features. Our goal was to identify the spectrum of CS practices in Canada, for both eloquent cortex mapping and seizure stimulation. METHODS: An online survey, answered by all 8 Canadian pediatric epilepsy centers, enquired about implantation, stimulation methods, and use of standardized protocols. A systematic literature review extracted detailed stimulation parameters. RESULTS: Most of the institutions (n = 7/8) reported performing CS during presurgical evaluation. Four institutions indicated they perform stimulation in all implanted patients for the purpose of eloquent cortex mapping and seizure stimulation. The majority of physicians had their individual approach to CS. A largely variable approach to CS, mainly in the choice of stimulation parameters (i.e., train and pulse duration), was observed, with the highest variance concerning the purpose of seizure stimulation. The literature review highlighted an overall small sample size and minimal number of publications. Even though there is a rising trend towards stereotactic iEEG implantation, more data were available on subdural EEGs. CONCLUSION: This study shows individual and sparsely validated approach to CS in pediatric epilepsy. The literature review underscores the urgent need to harmonize pediatric intracranial EEG practices. More multicenter studies are needed to identify safe stimulation thresholds and allow implementation of evidence-based guidelines.

• Klíčová slova
• Brain mapping, Canada, Electrical cortical stimulation, Electroencephalography, Epilepsy, Intracranial EEG, National survey, Pediatric, SEEG, Systematic literature review,
• MeSH
• dítě MeSH
• elektroencefalografie metody   MeSH
• elektrokortikografie * metody   MeSH
• epilepsie * diagnóza   patofyziologie   MeSH
• lidé MeSH
• mapování mozku * metody   MeSH
• mozková kůra * patofyziologie   MeSH
• průzkumy a dotazníky MeSH
• záchvaty * diagnóza   patofyziologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• systematický přehled MeSH
• Geografické názvy
• Kanada MeSH

A new measure of complexity of multichannel EEG recordings is proposed. The quantity assesses the diversity of activities of different brain generators contributing to the global dynamics of electric field of brain.

• MeSH
• biologické modely MeSH
• elektroencefalografie statistika a číselné údaje   MeSH
• lidé MeSH
• mapování mozku * MeSH
• mozek fyziologie   MeSH
• spánek fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The tamoxifen-inducible Cre-loxP system is widely used to overcome gene targeting pre-adult lethality, to modify a specific cell population at desired time-points, and to visualize and trace cells in fate-mapping studies. In this study we focused on tamoxifen degradation kinetics, because for all genetic fate-mapping studies, the period during which tamoxifen or its metabolites remain active in the CNS, is essential. Additionally, we aimed to define the tamoxifen administration scheme, enabling the maximal recombination rate together with minimal animal mortality. The time window between tamoxifen injection and the beginning of experiments should be large enough to allow complete degradation of tamoxifen and its metabolites. Otherwise, these substances could promote an undesired recombination, leading to data misinterpretation. We defined the optimal time window, allowing the complete degradation of tamoxifen and its metabolites, such as 4-hydroxytamoxifen, N-desmethyltamoxifen, endoxifen and norendoxifen, in the mouse brain after intraperitoneal tamoxifen injection. We determined the biological activity of these substances in vitro, as well as a minimal effective concentration of the most potent metabolite 4-hydroxytamoxifen causing recombination in vivo. For this purpose, we analyzed the recombination rate in double transgenic Cspg4-cre/Esr1/ROSA26Sortm14(CAG-tdTomato) mice, in which tamoxifen administration triggers the expression of red fluorescent protein in NG2-expressing cells, and employed a liquid chromatography, coupled with mass spectrometry, to determine the concentration of studied substances in the brain. We determined the degradation kinetics of these substances, and revealed that this process is influenced by mouse strains, age of animals, and dosage. Our results revealed that tamoxifen and its metabolites were completely degraded within 8 days in young adult C57BL/6J mice, while the age-matched FVB/NJ male mice displayed more effective degradation. Moreover, aged C57BL/6J mice were unable to metabolize all substances within 8 days. The lowering of initial tamoxifen dose leads to a significantly faster degradation of all studied substances. A disruption of the blood-brain barrier caused no concentration changes of any tamoxifen metabolites in the ipsilateral hemisphere. Taken together, we showed that tamoxifen metabolism in mouse brains is age-, strain- and dose-dependent, and these factors should be taken into account in the experimental design.

• Klíčová slova
• Cre-loxP, brain metabolism, fate-mapping, gene-targeting, tamoxifen,
• Publikační typ
• časopisecké články MeSH

Magnetic resonance spectroscopic imaging (MRSI) enables the simultaneous noninvasive acquisition of MR spectra from multiple spatial locations inside the brain. Although 1H-MRSI is increasingly used in the human brain, it is not yet widely applied in the preclinical setting, mostly because of difficulties specifically related to very small nominal voxel size in the rat brain and low concentration of brain metabolites, resulting in low signal-to-noise ratio (SNR). In this context, we implemented a free induction decay 1H-MRSI sequence (1H-FID-MRSI) in the rat brain at 14.1 T. We combined the advantages of 1H-FID-MRSI with the ultra-high magnetic field to achieve higher SNR, coverage, and spatial resolution in the rat brain and developed a custom dedicated processing pipeline with a graphical user interface for Bruker 1H-FID-MRSI: MRS4Brain toolbox. LCModel fit, using the simulated metabolite basis set and in vivo measured MM, provided reliable fits for the data at acquisition delays of 1.30 ms. The resulting Cramér-Rao lower bounds were sufficiently low (< 30%) for eight metabolites of interest (total creatine, N-acetylaspartate, N-acetylaspartate + N-acetylaspartylglutamate, total choline, glutamine, glutamate, myo-inositol, and taurine), leading to highly reproducible metabolic maps. Similar spectral quality and metabolic maps were obtained with one and two averages, with slightly better contrast and brain coverage due to increased SNR in the latter case. Furthermore, the obtained metabolic maps were accurate enough to confirm the previously known brain regional distribution of some metabolites. The acquisitions proved high reproducibility over time. We demonstrated that the increased SNR and spectral resolution at 14.1 T can be translated into high spatial resolution in 1H-FID-MRSI of the rat brain in 13 min using the sequence and processing pipeline described herein. High-resolution 1H-FID-MRSI at 14.1 T provided robust, reproducible, and high-quality metabolic mapping of brain metabolites with minimal technical limitations.

• Klíčová slova
• 1H‐FID‐MRSI, brain metabolites, magnetic resonance spectroscopic imaging, metabolite mapping, rat brain, ultra‐high field,
• MeSH
• krysa rodu Rattus MeSH
• magnetická rezonanční tomografie metody   MeSH
• metabolom MeSH
• mozek * metabolismus   diagnostické zobrazování   MeSH
• poměr signál - šum MeSH
• potkani Sprague-Dawley MeSH
• potkani Wistar MeSH
• protonová magnetická rezonanční spektroskopie metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Parkinson's disease (PD) is a common neurodegenerative disease, and apart from a few rare genetic causes, its pathogenesis remains largely unclear. Recent scientific interest has been captured by the involvement of iron biochemistry and the disruption of iron homeostasis, particularly within the brain regions specifically affected in PD. The advent of Quantitative Susceptibility Mapping (QSM) has enabled non-invasive quantification of brain iron in vivo by MRI, which has contributed to the understanding of iron-associated pathogenesis and has the potential for the development of iron-based biomarkers in PD. This review elucidates the biochemical underpinnings of brain iron accumulation, details advancements in iron-sensitive MRI technologies, and discusses the role of QSM as a biomarker of iron deposition in PD. Despite considerable progress, several challenges impede its clinical application after a decade of QSM studies. The initiation of multi-site research is warranted for developing robust, interpretable, and disease-specific biomarkers for monitoring PD disease progression.

• Klíčová slova
• Iron, Magnetic resonance imaging, Parkinson's disease, Quantitative susceptibility mapping,
• MeSH
• biologické markery MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• mapování mozku metody   MeSH
• neurodegenerativní nemoci * MeSH
• neurozobrazování MeSH
• Parkinsonova nemoc * diagnostické zobrazování   patologie   MeSH
• progrese nemoci MeSH
• železo MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• biologické markery MeSH
• železo MeSH

Transcranial Magnetic Stimulation (TMS) is a non-invasive technique for analyzing the central and peripheral nervous system. TMS could be a powerful therapeutic technique for neurological disorders. TMS has also shown potential in treating various neurophysiological complications, such as depression, anxiety, and obsessive-compulsive disorders, without pain and analgesics. Despite advancements in diagnosis and treatment, there has been an increase in the prevalence of brain cancer globally. For surgical planning, mapping brain tumors has proven challenging, particularly those localized in expressive regions. Preoperative brain tumor mapping may lower the possibility of postoperative morbidity in surrounding areas. A navigated TMS (nTMS) uses magnetic resonance imaging (MRI) to enable precise mapping during navigated brain stimulation. The resulting magnetic impulses can be precisely applied to the target spot in the cortical region by employing nTMS. This review focuses on nTMS for preoperative planning for brain cancer. This study reviews several studies on TMS and its subtypes in treating cancer and surgical planning. nTMS gives wider and improved dimensions of preoperative planning of the motor-eloquent areas in brain tumor patients. nTMS also predicts postoperative neurological deficits, which might be helpful in counseling patients. nTMS have the potential for finding possible abnormalities in the motor cortex areas.

• Klíčová slova
• Glioma, language mapping., multi-locus TMS, navigated repetitive TMS, preoperative mapping, tDCS,
• MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• mapování mozku metody   MeSH
• motorické korové centrum diagnostické zobrazování   MeSH
• nádory mozku * chirurgie   MeSH
• neuronavigace metody   MeSH
• předoperační péče * metody   MeSH
• transkraniální magnetická stimulace * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: There are gaps in our neurobiological understanding of functional movement disorder (FMD). OBJECTIVES: We investigated gray matter volumetric profiles in FMD, and related findings to resting-state functional connectivity (rsFC) profiles using Human Connectome Project data. METHODS: Volumetric differences between 53 FMD patients and 50 controls were examined, as well as relationships between individual differences in FMD symptom severity and volumetric profiles. Atrophy network mapping was also used to probe whether FMD-related structural alterations preferentially impacted brain areas with dense rsFC. RESULTS: Compared to controls without neurological comorbidities (albeit with mild depression and anxiety as a group), the FMD cohort did not show any volumetric differences. Across patients with FMD, individual differences in symptom severity negatively correlated with right supramarginal and bilateral superior temporal gyri volumes. These findings remained significant adjusting for FMD subtype or antidepressant use, but did not remain statistically significant adjusting for depression and anxiety scores. Symptom severity-related structural alterations mapped onto regions with dense rsFC-identifying several disease epicenters in default mode, ventral attention, and salience networks. CONCLUSIONS: This study supports that FMD is a multinetwork disorder with an important role for the temporoparietal junction and its related connectivity in the pathophysiology of this condition. More research is needed to explore the intersection of functional neurological symptoms and mood.

• Klíčová slova
• MRI, functional connectivity, functional movement disorder, functional neurological disorder, salience network, temporoparietal junction,
• MeSH
• biologické markery MeSH
• dyskineze * MeSH
• konektom * MeSH
• konverzní poruchy * MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mapování mozku MeSH
• mozek diagnostické zobrazování   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• biologické markery MeSH

The stereotyped features of brain structure, such as the distribution, morphology and connectivity of neuronal cell types across brain areas, are those most likely to explain the remarkable capacity of the brain to process information and govern behaviors. Recent advances in anatomical methods, including the simple but versatile isotropic fractionator and several whole-brain labeling, clearing and microscopy methods, have opened the door to an exciting new era in comparative brain anatomy, one that has the potential to transform our understanding of the brain structure-function relationship by representing the evolution of brain complexity in quantitative anatomical features shared across species and species-specific or clade-specific. Here we discuss these methods and their application to mapping brain cell count and cell type distributions-two particularly powerful neural correlates of vertebrate cognitive and behavioral capabilities.

• MeSH
• druhová specificita MeSH
• mapování mozku * MeSH
• mozek * MeSH
• neurony MeSH
• počet buněk MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH