BACKGROUND: Changes in both the vascular system and brain tissues can occur after a prior episode of coronavirus disease 2019 (COVID-19), detectable through modifications in diffusion parameters using magnetic resonance imaging (MRI) techniques. These changes in diffusion parameters may be particularly prominent in highly organized structures such as the corpus callosum (CC), including its major components, which have not been adequately studied following COVID-19 infection. Therefore, the study aimed to evaluate microstructural changes in whole-brain (WB) diffusion, with a specific focus on the CC. METHODS: A total of 101 probands (age range from 18 to 69 years) participated in this retrospective study, consisting of 55 volunteers and 46 post-COVID-19 patients experiencing neurological symptoms. The participants were recruited from April 2022 to September 2023 at the Institute for Clinical and Experimental Medicine in Prague, Czech Republic. All participants underwent MRI examinations on a 3T MR scanner with a diffusion protocol, complemented by additional MRI techniques. Two volunteers and five patients were excluded from the study due to motion artefacts, severe hypoperfusion or the presence of lesions. Participants were selected by a neurologist based on clinical examination and a serological test for COVID-19 antibodies. They were then divided into three groups: a control group of healthy volunteers (n=28), an asymptomatic group (n=25) with a history of infection but no symptoms, and a symptomatic group (n=41) with a history of COVID-19 and neurological symptoms. Symptomatic patients did not exhibit neurological symptoms before contracting COVID-19. Diffusion data underwent eddy current and susceptibility distortion corrections, and fiber tracking was performed using default parameters in DSI studio. Subsequently, various diffusion metrics, were computed within the reconstructed tracts of the WB and CC. To assess the impact of COVID-19 and its associated symptoms on diffusion indices within the white matter of the WB and CC regions, while considering age, we employed a statistical analysis using a linear mixed-effects model within the R framework. RESULTS: Statistical analysis revealed a significant difference in mean diffusivity (MD) between the symptomatic and control groups in the forceps minor (P=0.001) and CC body (P=0.003). In addition to changes in diffusion, alterations in brain perfusion were observed in two post-COVID-19 patients who experienced a severe course. Furthermore, hyperintense lesions were identified in subcortical and deep white matter areas in the vast majority of symptomatic patients. CONCLUSIONS: The main finding of our study was that post-COVID-19 patients exhibit increased MD in the forceps minor and body of the CC. This finding suggests a potential association between microstructural brain changes in post-COVID-19 patients and reported neurological symptoms, with significant implications for research and clinical applications.
- Publikační typ
- časopisecké články MeSH
Background: Magnetic resonance (MR) tractography of the brachial plexus (BP) is challenging due to different factors such as motion artifacts, pulsation artifacts, signal-to-noise ratio, spatial resolution; eddy currents induced geometric distortions, sequence parameters and choice of used coils. Notably challenging is the separation of the peripheral nerve bundles and skeletal muscles as both structures have similar fractional anisotropy values. We proposed an algorithm for robust visualization and assessment of BP root bundles using the segmentation of the spinal cord (SSC, C4-T1) as seed points for the initial starting area for the fibre tracking algorithm. Methods: Twenty-seven healthy volunteers and four patients with root avulsions underwent magnetic resonance imaging (MRI) examinations on a 3T MR scanner with optimized measurement protocols for diffusion-weighted images and coronal T2 weighted 3D short-term inversion recovery sampling perfection with application optimized contrast using varying flip angle evaluation sequences used for BP fibre reconstruction and MR neurography (MRN). The fibre bundles reconstruction was optimized in terms of eliminating the skeletal muscle fibres contamination using the SSC and the tracking threshold of the normalized quantitative anisotropy (NQA) on reconstruction of the BP. In our study, the NQA parameter has been used for fiber tracking instead of fractional anisotropy (FA). The diffusion data were processed in individual C4-T1 root bundles using the generalized q-sampling imaging (GQI) algorithm. Calculated diffusion parameters were statistically analysed using the two-sample t-test. The MRN was performed in MedINRIA and post-processed using the maximum intensity projection (MIP) method to demonstrate BP root bundles in multiple planes. Results: In control subjects, no significant effect of laterality in diffusion parameters was found (P>0.05) in the BP. In the central part of the BP, a significant difference between control subjects and patients at P=0.02 was found in the NQA values. Other diffusion parameters were not significantly different. Conclusions: Using NQA instead of FA in the proposed algorithm allowed for a better separation of muscle and root nerve bundles. The presented algorithm yields a high quality reconstruction of the BP bundles that may be helpful both in research and clinical practice.
- Publikační typ
- časopisecké články MeSH
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
nestr.
Současný sedavý způsob života, při kterém strávíme mnoho hodin před obrazovkami televizí a počítačů může vést k poruchám periferního nervového systému (PNS). Pro zobrazení těchto chorob je třeba sofistikovaných zobrazovacích modalit, jako je např. magnetická rezonance (MR). Pokročilé metody MR zahrnující difúzně vážené zobrazování (DWI) resp. zobrazení difúzního tenzoru (DTI) a MR neurografie umožňují zkoumat mikroarchitekturu tkáně PNS. Z DWI dat lze na základě určení preferenčního směru difúze v PNS zobrazit hlavní nervové svazky a kvantitativně posoudit jejich integritu. MR neurografie pak poskytuje přesné 3D anatomické zobrazení periferních nervů. Tyto zmíněné metody byly úspěšně testovány u šesti dobrovolníků. Výsledky pilotní studie ukazují, že navrhovaná metodologie může být s výhodou použita v předoperačním plánování a postoperačním vyhodnocení stavu PNS. Pokročilé MR metody budou použity v navrhovaném projektu u kontrolních subjektů a pacientů s poruchami PNS a výsledky budou porovnány s elektromyografií, která se v klinice nyní běžně využívá.; A sedentary lifestyle with bad sitting posture for hours leads to peripheral nervous system (PNS) disorders. To detect these disorders, sophisticated imaging modalities such as Magnetic resonance imaging (MRI) are required. Besides conventional MRI techniques, advanced MR methods including diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI) and MR neurography enable evaluation of the microarchitecture of the PNS tissue. Based on the preferential direction of diffusion in PNS calculated from the DWI data it is possible to reconstruct the major neuronal bundles and to quantitatively assess their integrity. MR neurography then allows 3D visualization of peripheral nerves. The method has been successfully tested in 6 volunteers. Results of the pilot study show that the proposed methodology may be used in the presurgical planning as well as in the post-operative evaluation of PNS disorders. Advanced MR methods will be used in the proposed project for examination of control subjects and patients with PNS disorders and correlated with commonly used electromyography.
- MeSH
- elektromyografie MeSH
- magnetická rezonanční tomografie MeSH
- nemoci periferního nervového systému diagnostické zobrazování MeSH
- neuropatie brachiálního plexu diagnostické zobrazování MeSH
- plexus lumbosacralis diagnostické zobrazování patologie MeSH
- zobrazování difuzních tenzorů MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- neurologie
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
ABSTRACT: MR tractography of the lumbosacral plexus (LSP) is challenging due to the difficulty of acquiring high quality data and accurately estimating the neuronal tracts. We proposed an algorithm for an accurate visualization and assessment of the major LSP bundles using the segmentation of the cauda equina as seed points for the initial starting area for the fiber tracking algorithm.Twenty-six healthy volunteers underwent MRI examinations on a 3T MR scanner using the phased array coils with optimized measurement protocols for diffusion-weighted images and coronal T2 weighted 3D short-term inversion recovery sampling perfection with application optimized contrast using varying flip angle evaluation sequences used for LSP fiber reconstruction and MR neurography (MRN).The fiber bundles reconstruction was optimized in terms of eliminating the muscle fibers contamination using the segmentation of cauda equina, the effects of the normalized quantitative anisotropy (NQA) and angular threshold on reconstruction of the LSP. In this study, the NQA parameter has been used for fiber tracking instead of fractional anisotropy (FA) and the regions of interest positioning was precisely adjusted bilaterally and symmetrically in each individual subject.The diffusion data were processed in individual L3-S2 nerve fibers using the generalized Q-sampling imaging algorithm. Data (mean FA, mean diffusivity, axial diffusivity and radial diffusivity, and normalized quantitative anisotropy) were statistically analyzed using the linear mixed-effects model. The MR neurography was performed in MedINRIA and post-processed using the maximum intensity projection method to demonstrate LSP tracts in multiple planes.FA values significantly decreased towards the sacral region (P < .001); by contrast, mean diffusivity, axial diffusivity, radial diffusivity and NQA values significantly increased towards the sacral region (P < .001).Fiber tractography of the LSP was feasible in all examined subjects and closely corresponded with the nerves visible in the maximum intensity projection images of MR neurography. Usage of NQA instead of FA in the proposed algorithm enabled better separation of muscle and nerve fibers.The presented algorithm yields a high quality reconstruction of the LSP bundles that may be helpful both in research and clinical practice.
- MeSH
- algoritmy MeSH
- anizotropie MeSH
- cauda equina diagnostické zobrazování MeSH
- difuzní magnetická rezonance metody MeSH
- dospělí MeSH
- lidé MeSH
- lumbosakrální krajina inervace MeSH
- magnetická rezonanční tomografie metody MeSH
- míšní nervy anatomie a histologie diagnostické zobrazování MeSH
- plexus lumbosacralis diagnostické zobrazování MeSH
- počítačové zpracování obrazu metody MeSH
- zobrazování difuzních tenzorů metody MeSH
- zobrazování trojrozměrné přístrojové vybavení MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
MR traktografie (MRT) se stala v posledních letech velmi důležitou a neinvazivní metodou zobrazení svazků bílé hmoty a periferních nervů měřením difúze molekul vody magnetickou rezonancí. Zde je uveden krátký historický vývoj a implementace MRT do klinické praxe na našem pracovišti IKEM. Dále je uveden stručný přehled některých aplikací MRT mozku a 3D MR neurografíe (MRN) periferních nervů. Obě metody mohou hrát důležitou roli při plánování neurochirurgických operací a sledování postoperačních změn mozkových a periferních nervových mikrostruktur.
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.
Ačkoliv konvenční techniky zobrazení magnetickou rezonancí mají dominantní postavení při vyšetření centrálního nervového systému, přesto tyto techniky nedokážou dát informaci o funkčních vlastnostech mozkové tkáně. Kromě konvenčních MR technik však existují i MR metody umožňující některé z těchto vlastností zobrazit. Mezi ně můžeme zařadit funkční magnetickou rezonanci, difuzně vážené zobrazování, resp. zobrazení difuzního tenzoru a morfometrickou analýzu. Tento článek podává přehled fyzikálních základů zmíněných MR metod a jejich využití ve výzkumu a klinické praxi.
Although conventional MR imaging techniques play a crucial role in the examination of the central nervous system, these techniques can not give any information about functional properties of the brain tissue. Besides conventional MRI techniques, however, there are some MR methods enabling evaluation of these functional properties. These methods include functional magnetic resonance imaging, diffusion-weighted imaging or diffusion tensor imaging, and voxel based morphometry This article presents the basic physical concepts of the above-mentioned MR techniques and the
- MeSH
- algoritmy MeSH
- anizotropie MeSH
- kognitivní věda metody přístrojové vybavení trendy MeSH
- lidé MeSH
- magnetická rezonanční tomografie * metody využití MeSH
- moire topografie metody využití MeSH
- mozek fyziologie patofyziologie patologie MeSH
- neurovědy * metody přístrojové vybavení trendy MeSH
- neurozobrazování * metody přístrojové vybavení využití MeSH
- počítačové zpracování obrazu metody přístrojové vybavení využití MeSH
- statistika jako téma MeSH
- zobrazování difuzních tenzorů metody využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
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INTRODUCTION: Modulation of neurodegeneration by physical activity is an active topic in contemporary research. The purpose of this study was to investigate changes in the brain's microstructure in multiple sclerosis (MS) after facilitation physiotherapy. METHODS: Eleven patients with MS were examined using motor and neuropsychological testing and multimodal MRI at the beginning of the study, with second baseline measurement after 1 month without any therapy, and after a 2-month period of facilitation physiotherapy. Eleven healthy controls were examined at the beginning of the study and after 1 month. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ (ax)), and radial diffusivity (λ (rad)) were calculated for the whole corpus callosum (CC) in the midsagittal slice of T1W 3D MPRAGE spatially normalized images. Data were analyzed using linear mixed-effect models, paired, and two-sample tests. RESULTS: At the baseline, patients with MS showed significantly lower values in FA (p < 0.001), and significantly higher values in MD (p < 0.001), λ (ax) (p = 0.003), and λ (rad) (p < 0.001) compared to control subjects. The FA, MD, λ (ax), and λ (rad) did not change between the first and second baseline examinations in either group. Differences 2 months after initiating facilitation physiotherapy were in FA, MD, and in λ (rad) significantly higher than differences in healthy controls (p < 0.001 for FA, p = 0.02 for MD, and p = 0.002 for λ (rad)). In MS patients, FA in the CC significantly increased (p < 0.001), MD and λ (rad) significantly decreased (p = 0.014 and p = 0.002), and thus approached the values in healthy controls. CONCLUSION: The results of the study show that facilitation physiotherapy influences brain microstructure measured by DTI.
- MeSH
- anizotropie MeSH
- corpus callosum patologie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- modely neurologické MeSH
- neuropsychologické testy MeSH
- počítačové zpracování obrazu MeSH
- roztroušená skleróza patologie terapie MeSH
- studie případů a kontrol MeSH
- techniky fyzikální terapie MeSH
- výsledek terapie MeSH
- zobrazování difuzních tenzorů metody 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
OBJECTIVE: The aim of the study was to assess structural changes in gray matter (GM) volume and fractional anisotropy (FA) in patients with Alzheimer's disease (AD) compared to control subjects using Voxel-Based Morphometry (VBM). Fractional anisotropy in the corpus callosum of both groups was also calculated using ROI analysis. METHODS: Twenty-one patients and twenty-three control subjects underwent MRI examination using T1-weighted 3D MPRAGE sequence and diffusion spin-echo echo-planar imaging sequence in six directions. Structural MRI analyses for GM volume and FA were performed using an optimized VBM protocol implemented in SPM5. The influence of age and Mini-Mental State Examination (MMSE) was dealt with multiple regression analysis either for the whole group or for AD patients and controls separately. RESULTS: Patients showed significant reduction of GM volume mainly in the temporal lobes. In AD patients, no correlation was observed between GM volume and age or MMSE. FA was reduced in AD patients mainly in frontal and temporal lobes. In both groups no correlation was found between FA and age or MMSE. Patients with AD showed a significant decrease in FA and an increase in mean diffusivity (p<0.0001) in the corpus callosum. CONCLUSIONS: In patients with AD we observed a significant reduction in FA values and GM volume; however, no correlation with age and MMSE was proven for both FA and GM for AD patients. This finding supports the hypothesis that morphological changes in patients with AD are not a continuous aging related process but represent qualitative changes.
- MeSH
- Alzheimerova nemoc diagnóza MeSH
- anizotropie MeSH
- corpus callosum patologie radiografie MeSH
- difuzní magnetická rezonance metody MeSH
- echoplanární zobrazování metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- psychologické testy MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- věkové faktory MeSH
- velikost orgánu MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- klinické zkoušky kontrolované MeSH
- práce podpořená grantem MeSH
Cílem naší studie bylo hodnocení změn mikroarchitektury bílé hmoty in vivo v corpus callosum metodou zobrazení difúzního tenzoru (DTI) u pacientů s Alzheimerovou nemocí (AN) ve srovnání s kontrolní skupinou. Všechny subjekty byly podrobeny kognitivnímu testu Mini Mental State Examination (MMSE) a vyšetřeny magnetickou rezonancí na 3T tomografu Siemens Trio. Na DTI datech byla nejdříve provedena korekce pohybových artefaktů v programu FSL. Data byla následně normalizována a analyzována softwarem MedINRIA. Pro každý subjekt byly spočteny hodnoty frakční anizotropie (FA) a aparentního difúzního koeficientu (ADC) v celém corpus callosum a v jeho hlavních částech (v genu, truncus a splenium) zvlášť. Výsledky studie prokázaly nižší hodnoty FA v corpus callosum u pacientů s AN v porovnání s kontrolní skupinou. Významná redukce FA (/? < 0,002) a narůst ADC {p < 0,01) u pacientů s AN v corpus callosum ukazují na poškození axonů největšího komisurálního svazku bílé hmoty.
The aim of our study was to assess the integrity of white matter in vivo in the corpus callosum in patients with Alzheimer's disease (AD) compared to control subjects using diffusion tensor imaging (DTI). All subjects underwent Mini Mental State Examination test (MMSE) and MRI examination on a 3T MR scanner, Siemens Trio. DTI data were corrected for motion artifacts using FSL, normalized and evaluated in MedINRIA. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were then calculated in the corpus callosum and in the genu, body and splenium separately. Patients with AD showed significant lower FA (p < 0,002) and higher ADC (p < 0,01) values in the corpus callosum. A significant decrease of FA and an increase of ADC values in patients with AD indicate damage of the axons of the biggest commissural bundle of the white matter.
