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
OBJECTIVE: Many patients with long COVID experience neurological and psychological symptoms. Signal abnormalities on MR images in the corpus callosum have been reported. Knowledge about the metabolic profile in the splenium of the corpus callosum (CCS) may contribute to a better understanding of the pathophysiology of long COVID. MATERIALS AND METHODS: Eighty-one subjects underwent proton MR spectroscopy examination. The metabolic concentrations of total N-acetylaspartate (NAA), choline-containing compounds (Cho), total creatine (Cr), myo-inositol (mI), and NAA/Cho in the CCS were statistically compared in the group of patients containing 58 subjects with positive IgG COVID-19 antibodies or positive SARS-CoV-2 qPCR test at least two months before the MR and the group of healthy controls containing 23 subjects with negative IgG antibodies. RESULTS: An age-dependent effect of SARS-CoV-2 on Cho concentrations in the CCS has been observed. Considering the subjective threshold of age = 40 years, older patients showed significantly increased Cho concentrations in the CCS than older healthy controls (p = 0.02). NAA, Cr, and mI were unchanged. All metabolite concentrations in the CCS of younger post-COVID-19 patients remained unaffected by SARS-CoV-2. Cho did not show any difference between symptomatic and asymptomatic patients (p = 0.91). DISCUSSION: Our results suggest that SARS-CoV-2 disproportionately increases Cho concentration in the CCS among older post-COVID-19 patients compared to younger ones. The observed changes in Cho may be related to the microstructural reorganization in the CCS also reported in diffusion measurements rather than increased membrane turnover. These changes do not seem to be related to neuropsychological problems of the post-COVID-19 patients. Further metabolic studies are recommended to confirm these observations.
- MeSH
- cholin * metabolismus MeSH
- corpus callosum * diagnostické zobrazování metabolismus MeSH
- COVID-19 * diagnostické zobrazování metabolismus MeSH
- dospělí MeSH
- inositol metabolismus MeSH
- kreatin * metabolismus MeSH
- kyselina aspartová * analogy a deriváty metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody MeSH
- protonová magnetická rezonanční spektroskopie * metody MeSH
- SARS-CoV-2 * MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Publikační typ
- abstrakt z konference MeSH
The volume reduction of the gray matter structures in patients with Alzheimer's disease is often accompanied by an asymmetric increase in the number of white matter fibers located close to these structures. The present study aims to investigate the white matter structure changes in the motor basal ganglia in Alzheimer's disease patients compared to healthy controls using diffusion tensor imaging. The amounts of tracts, tract length, tract volume, quantitative anisotropy, and general fractional anisotropy were measured in ten patients with Alzheimer's disease and ten healthy controls. A significant decrease in the number of tracts and general fractional anisotropy was found in patients with Alzheimer's disease compared to controls in the right caudate nucleus, while an increase was found in the left and the right putamen. Further, a significant decrease in the structural volume of the left and the right putamen was observed. An increase in the white matter diffusion tensor imaging parameters in patients with Alzheimer's disease was observed only in the putamen bilaterally. The right caudate showed a decrease in both the diffusion tensor imaging parameters and the volume in Alzheimer's disease patients. The right pallidum showed an increase in the diffusion tensor imaging parameters but a decrease in volume in Alzheimer's disease patients.
- MeSH
- Alzheimerova nemoc * diagnostické zobrazování MeSH
- bílá hmota * diagnostické zobrazování MeSH
- lidé MeSH
- putamen diagnostické zobrazování MeSH
- šedá hmota diagnostické zobrazování MeSH
- zobrazování difuzních tenzorů metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem 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
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
AIMS: The purpose of the study was to evaluate the reliability of our new visual scale for a quick atrophy assessment of parietal lobes on brain Magnetic Resonance Imaging (MRI) among different professionals. A good agreement would justify its use for differential diagnosis of neurodegenerative dementias, especially early-onset Alzheimer's Disease (AD), in clinical settings. METHODS: The visual scale named the Parietal Atrophy Score (PAS) is based on a semi-quantitative assessment ranging from 0 (no atrophy) to 2 (prominent atrophy) in three parietal structures (sulcus cingularis posterior, precuneus, parietal gyri) on T1-weighted MRI coronal slices through the whole parietal lobes. We used kappa statistics to evaluate intra-rater and inter-rater agreement among four raters who independently scored parietal atrophy using PAS. Rater 1 was a neuroanatomist (JM), rater 2 was an expert in MRI acquisition and analysis (II), rater 3 was a medical student (OP) and rater 4 was a neurologist (DS) who evaluated parietal atrophy twice in a 3-month interval to assess intra-rater agreement. All raters evaluated the same 50 parietal lobes on brain MRI of 25 cognitively normal individuals with even distribution across all atrophy degrees from none to prominent according to the neurologist's rating. RESULTS: Intra-rater agreement was almost perfect with the kappa value of 0.90. Inter-rater agreement was moderate to substantial with kappa values ranging from 0.43-0.86. CONCLUSION: The Parietal Atrophy Score is the reliable visual scale among raters of different professions for a quick evaluation of parietal lobes on brain MRI within 1-2 minutes. We believe it could be used as an adjunct measure in differential diagnosis of dementias, especially early-onset AD.
- MeSH
- atrofie MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mozek diagnostické zobrazování patologie MeSH
- neurozobrazování MeSH
- odchylka pozorovatele MeSH
- reprodukovatelnost výsledků MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- stupeň závažnosti nemoci MeSH
- temenní lalok diagnostické zobrazování patologie MeSH
- testy pro posouzení mentálních funkcí a demence MeSH
- vizuální analogová stupnice MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Zobrazení brachiálního plexu (BP) a lumbosakrálního plexu (LSP) pomocí magnetické rezonance (MR) umožní získat detailní informace využitelné v rámci diagnostiky i léčby postižení těchto komplexních nervových pletení. Techniky MR využitelné ke zobrazení BP a LSP zahrnují metody konvenční, MR neurografii (MRN), zobrazení difuzního tenzoru (DTI) a MR traktografii (MRT). MRN poskytuje data o detailní anatomické struktuře, DTI a MRT vypovídají o funkční integritě nervových vláken. S dalším vývojem a zlepšováním těchto pokročilých technik MR lze předpokládat jejich postupné zavádění do standardních vyšetřovacích protokolů MR.
Visualization of the brachial plexus (BP) and lumbosacral plexus (LSP) by magnetic resonance imaging (MRI) allows us to obtain detailed information useful in diagnosing and treatment of disorders affecting these complex nerve structures. MR techniques helpful in visualising BP and LSP include conventional methods, MR neurography (MRN), diffuse tensor imaging (DTI) and MR tractography (MRT). MRN provides detailed analysis of anatomical structure, DTI and MRT inform us on the functional integrity of the nerve fibers. With continuing development and improvement of these advanced MR techniques, we can assume their gradual introduction into standard MR protocols.
- MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- neurozobrazování metody MeSH
- plexus brachialis * diagnostické zobrazování MeSH
- plexus lumbosacralis * diagnostické zobrazování MeSH
- zobrazování difuzních tenzorů metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Ratios between opposing volumes from brain magnetic resonance imaging (MRI) can provide additional information to volumes in Alzheimer's disease (AD). Brain three-dimensional MPRAGE MRI at 3T were segmented into 44 regions using FreeSurfer v6 in 75 participants. The region's size in absolute volumes and relative proportions to the whole brain volume were compared between 39 AD patients and 36 age-, education- and sex-matched normal controls (NC). Volumes of the most atrophied parts were related to the opposing volumes of the most enlarged parts as ratios. The most atrophic structures in AD were both hippocampi. By contrast, the greatest enlargements in AD were inferior parts of both lateral ventricles. The best ratio for each side was the hippocampo-horn proportion calculated as ratio: the hippocampus / (the hippocampus + inferior lateral ventricle). Its optimal cut-off of 74% yielded sensitivity of 74% and specificity of 78% on the left and sensitivity of 74% and specificity of 78% on the right. The hippocampo-horn proportion is another measure to evaluate the degree of hippocampal atrophy on brain MRI in percentages. It has a potential to be simplified into a comparison of two-dimensional corresponding areas or a visual assessment.
- MeSH
- algoritmy MeSH
- Alzheimerova nemoc patologie MeSH
- atrofie patologie MeSH
- hipokampus patologie MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mozek patologie MeSH
- senzitivita a specificita MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Cíl: Naším záměrem bylo posoudit, zda by se při diagnostice Alzheimerovy nemoci s pozdním začátkem dalo využít skórování parietální atrofie na MR mozku pomocí jednoduché vizuální metodiky označené zkratkou PAS (Parietální atrofický skór). Soubor a metody: Strukturu parietálních laloků jsme hodnotili námi vyvinutou vizuální škálou PAS, která je založena na semikvantitativním skórování atrofie tří struktur v parietální oblasti: sulcus cingularis posterior, precuneus a parietální gyry. Parietální atrofie byla posuzována u 24 pacientů s Alzheimerovou nemocí s pozdním začátkem ve stadiu mírné demence (Mini-Mental State Examination; MMSE 21 ± 3 body) a 26 věkově vázaných jedinců s normálním výsledkem testu kognitivních funkcí (MMSE 29 ± 1 bod). Výsledky: Podle vizuální škály PAS nebyl prokázán statisticky významný rozdíl ve velikosti žádné z hodnocených struktur pravého ani levého parietálního laloku mezi pacienty s Alzheimerovou nemocí a kontrolními jedinci (ve všech případech p > 0,05). Závěr: Během Alzheimerovy nemoci s pozdním začátkem nedochází do stadia mírné demence k výraznějšímu úbytku parietální kůry, než by odpovídalo běžnému stárnutí. Parietální atrofie hodnocená podle metodiky PAS není vhodným ukazatelem, který by se dal využít při diagnostice počátečních stadií Alzheimerovy nemoci s pozdním začátkem.
Aim: Our intention was to assess whether a scoring of parietal atrophy on MRI of the brain using a simple visual assessment named PAS (Parietal Atrophy Score) could be used in the diagnosis of late-onset Alzheimer´s disease. Patients and methods: The structure of the parietal lobes was evaluated by our visual scale named PAS, which is based on semiquantitative scoring of atrophy of three structures in the parietal region: sulcus cingularis posterior, precuneus and parietal gyri. Parietal atrophy was assessed in 24 patients with late-onset Alzheimer´s disease in the stage of mild dementia (Mini-Mental State Examination; MMSE 21 ± 3 points) and 26 age-matched individuals with normal scores on the MMSE (29 ± 1 point). Results: We did not find any statistically significant difference in the size of any structure of the right and left parietal lobe according to the PAS visual scale between control individuals and patients with Alzheimer´s disease (p > 0.05 in all cases). Conclusion: During late-onset Alzheimer´s disease there is no significant reduction of parietal cortex until the stage of mild dementia compared to normal aging. Parietal atrophy evaluated according to the PAS visual scale is not an appropriate marker to be used in the diagnosis of late-onset Alzheimer´s disease in mild stages.
- Klíčová slova
- arietální atrofický skór, parietální atrofie, sulcus cingularis posterior, parietální gyry,
- MeSH
- Alzheimerova nemoc * diagnostické zobrazování diagnóza MeSH
- demence MeSH
- klinická studie jako téma MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- neurozobrazování metody MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- stárnutí MeSH
- temenní lalok diagnostické zobrazování MeSH
- Check Tag
- lidé MeSH
- senioři nad 80 let MeSH
- senioři MeSH
