Structural analysis of brain hub region volume and cortical thickness in patients with mild cognitive impairment and dementia

Publisher Copyright: © 2020 by the authors. Licensee MDPI, Basel, Switzerland. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background and Objectives: A complex network of axonal pathways interlinks the human brain cortex. Brain networks are not distributed evenly, and brain regions making more connections with other parts are defined as brain hubs. Our objective was to analyze brain hub region volume and cortical thickness and determine the association with cognitive assessment scores in patients with mild cognitive impairment (MCI) and dementia. Materials and Methods: In this cross-sectional study, we included 11 patients (5 mild cognitive impairment; 6 dementia). All patients underwent neurological examination, and Montreal Cognitive Assessment (MoCA) test scores were recorded. Scans with a 3T MRI scanner were done, and cortical thickness and volumetric data were acquired using Freesurfer 7.1.0 software. Results: By analyzing differences between the MCI and dementia groups, MCI patients had higher hippocampal volumes (p <0.05) and left entorhinal cortex thickness (p <0.05). There was a significant positive correlation between MoCA test scores and left hippocampus volume (r = 0.767, p <0.01), right hippocampus volume (r = 0.785, p <0.01), right precuneus cortical thickness (r = 0.648, p <0.05), left entorhinal cortex thickness (r = 0.767, p <0.01), and right entorhinal cortex thickness (r = 0.612, p <0.05). Conclusions: In our study, hippocampal volume and entorhinal cortex showed significant differences in the MCI and dementia patient groups. Additionally, we found a statistically significant positive correlation between MoCA scores, hippocampal volume, entorhinal cortex thickness, and right precuneus. Although other brain hub regions did not show statistically significant differences, there should be additional research to evaluate the brain hub region association with MCI and dementia.publishersversionPeer reviewe

Cerebellar Cortex and Cerebellar White Matter Volume in Normal Cognition, Mild Cognitive Impairment, and Dementia

Funding Information: Funding: The article has been developed with financing from the European Social Fund and the state budget within the project no. 8.2.2.0/20/I/004 “Support for involving doctoral students in sci‐ entific research and studies”. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The cerebellum is commonly viewed as a structure that is primarily responsible for the coordination of voluntary movement, gait, posture, and speech. Recent research has shown evidence that the cerebellum is also responsible for cognition. We analyzed 28 participants divided into three groups (9 with normal cognition, 9 with mild cognitive impairment, and 10 with moderate/severe cognitive impairment) based on the Montreal Cognitive Assessment. We analyzed the cerebellar cortex and white matter volume and assessed differences between groups. Participants with normal cognition had higher average values in total cerebellar volume, cerebellar white matter volume, and cerebellar cortex volume in both hemispheres, but by performing the Kruskal–Wallis test, we did not find these values to be statistically significant.publishersversionPeer reviewe

Combined Score of Perivascular Space Dilatation and White Matter Hyperintensities in Patients with Normal Cognition, Mild Cognitive Impairment, and Dementia

Funding Information: Funding: This research has been developed with financing from the European Social Fund and Latvian state budget within the project no. 8.2.2.0/20/I/004 “Support for involving doctoral students in scientific research and studies” at R¯ıga Stradin,š University. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Background and Objectives: Cerebral perivascular spaces (PVS) are part of the cerebral microvascular structure and play a role in lymphatic drainage and the removal of waste products from the brain. White matter hyperintensities (WMH) are hyperintense lesions on magnetic resonance imaging that are associated with cognitive impairment, dementia, and cerebral vascular disease. WMH and PVS are direct and indirect imaging biomarkers of cerebral microvascular integrity and health. In our research, we evaluated WMH and PVS enlargement in patients with normal cognition (NC), mild cognitive impairment (MCI), and dementia (D). Materials and Methods: In total, 57 participants were included in the study and divided into groups based on neurological evaluation and Montreal Cognitive Assessment results (NC group 16 participants, MCI group 29 participants, D group 12 participants). All participants underwent 3T magnetic resonance imaging. PVS were evaluated in the basal ganglia, centrum semiovale, and midbrain. WMHs were evaluated based on the Fazekas scale and the division between deep white matter (DWM) and periventricular white matter (PVWM). The combined score based on PVS and WMH was evaluated and correlated with the results of the MoCA. Results: We found statistically significant differences between groups on several measures. Centrum semiovale PVS dilatation was more severe in MCI and dementia group and statistically significant differences were found between D-MCI and D-NC pairs. PVWM was more severe in patients with MCI and dementia group, and statistically significant differences were found between D-MCI and D-NC pairs. Furthermore, we found statistically significant differences between the groups by analyzing the combined score of PVS dilatation and WMH. We did not find statistically significant differences between the groups in PVS dilation of the basal ganglia and midbrain and DWM hyperintensities. Conclusions: PVS assessment could become one of neuroimaging biomarkers for patients with cognitive decline. Furthermore, the combined score of WMH and PVS dilatation could facilitate diagnostics of cognitive impairment, but more research is needed with a larger cohort to determine the use of PVS dilatation and the combined score.publishersversionPeer reviewe

Intriguing findings of liver fibrosis following COVID-19

Funding Information: The authors would like to thank the Boris and Inara Teterev Foundation, R?ga Stradi?? University, and Riga East Clinical University Hospital for organizational support. Funding Information: The study was funded by the Ministry of Education and Science of the, Republic of Latvia, project “Clinical, biochemical, immunogenetic paradigms of Covid-19 infection and their correlation with socio-demographic, etiological, pathogenetic, diagnostic, therapeutically and prognostically important factors to be included in guidelines”, project No. VPP-COVID-2020/1-0023. Publisher Copyright: © 2021, The Author(s).Background: Studies on a new coronavirus disease (COVID-19) show the elevation of liver enzymes and liver fibrosis index (FIB-4) independently on pre-existing liver diseases. It points to increased liver fibrogenesis during acute COVID-19 with possible long-term consequences. This study aimed to assess liver fibrosis in COVID-19 patients by serum hyaluronic acid (HA) and FIB-4. Methods: The study included the acute COVID-19 group (66 patients, 50% females, mean age 58.3 ± 14.6), the post-COVID group (58 patients in 3–6 months after the recovery, 47% females, mean age 41.2 ± 13.4), and a control group (17 people, 47% females, mean age 42.8 ± 11.0). Ultrasound elastography was performed in the post-COVID and control groups. Results: Sixty-five percent of the acute COVID-19 group had increased FIB-4 (> 1.45), and 38% of patients had FIB-4 ≥ 3.25. After matching by demographics, 52% of acute COVID-19 and 5% of the post-COVID group had FIB-4 > 1.45, and 29% and 2% of patients had FIB-4 ≥ 3.25, respectively. Increased serum HA (≥ 75 ng/ml) was observed in 54% of the acute COVID-19 and 15% of the post-COVID group. In the acute COVID-19 group, HA positively correlated with FIB-4, AST, ALT, LDH, IL-6, and ferritin and negatively with blood oxygen saturation. In the post-COVID group, HA did not correlate with FIB-4, but it was positively associated with higher liver stiffness and ALT. Conclusion: More than half of acute COVID-19 patients had increased serum HA and FIB-4 related to liver function tests, inflammatory markers, and blood oxygen saturation. It provides evidence for the induction of liver fibrosis by multiple factors during acute COVID-19. Findings also indicate possible liver fibrosis in about 5% of the post-COVID group.publishersversionPeer reviewe

3D Medical Image Visualization and Volume Estimation of Pathology Zones

Medical image 3D visualization is one of the fundamental processes in medical diagnostics. Using the acquired 3D images it is possible to find the volume of pathology zone, which is the evidence of a specific disease. As a consequence, two problems emerge: visualization of 3D medical images and pathology zone extraction from acquired images. Available imaging software in some cases provides the con-struction of 3D images based upon various medical data ob-tained by computer tomography, magnetic resonance imaging, scintigraphy, etc. But further processing of these images (image segmentation, pathology zone extraction) can result in loss of information during initial image reconstruction. Furthermore, existing medical imaging software does not provide the automatic extraction of regions of interest. As a consequence, often pathology zone volumes are calculated manually and that results in lack of precision. In this work methods for solving these problems are pro-posed. This work describes an approach of 3D model recon-struction from medical images by using detailed initial infor-mation obtained for forming DICOM files. For extraction of pathology zones and volume estimation an automatic proce-dure of region calculation is proposed. The described methods can provide practical improvements to the reliability of medical diagnostics

Brain structural connectivity differences in patients with normal cognition and cognitive impairment

Publisher Copyright: © 2021 by the authors.Advances in magnetic resonance imaging, particularly diffusion imaging, have allowed researchers to analyze brain connectivity. Identification of structural connectivity differences between patients with normal cognition, cognitive impairment, and dementia could lead to new biomarker discoveries that could improve dementia diagnostics. In our study, we analyzed 22 patients (11 control group patients, 11 dementia group patients) that underwent 3T MRI diffusion tensor imaging (DTI) scans and the Montreal Cognitive Assessment (MoCA) test. We reconstructed DTI images and used the Desikan-Killiany-Tourville cortical parcellation atlas. The connectivity matrix was calculated, and graph theoretical analysis was conducted using DSI Studio. We found statistically significant differences between groups in the graph density, network characteristic path length, small-worldness, global efficiency, and rich club organization. We did not find statistically significant differences between groups in the average clustering coefficient and the assortativity coefficient. These statistically significant graph theory measures could potentially be used as quantitative biomarkers in cognitive impairment and dementia diagnostics.publishersversionPeer reviewe

Neurodegenerative constraints in stimulus-driven eye movements

Eye tracking is a promising and non-invasive method for assessing cognitive processes in neurodegeneration. Our study focuses on the use of stimulus-driven eye tracking as a tool for discovering neurodegenerative conditions. In this study, we examine perceptual organisation (grouping, segmentation), and accentuation (Pinna &amp; Sirigu, 2011) in neurologically impaired and healthy individuals. Based on a preliminary analysis, there are differences in the average number of fixations between clinical and control groups. Additionally, there are variations in the scanned area within specific sets of stimuli between the control and clinical groups. By identifying these differences, our study contributes to a deeper understanding of the mid-level perceptual processes in neurodegeneration

Visual accentuation constrains the structure of perceptual organization

Perceptual organization contains two interrelated sets of phenomena: visual grouping and figure-ground segmentation. Different types of grouping and segmenting (and interaction and competition between them) have been described. Less clear is what happens once an accent is added in grouping or segmenting. According to several eye tracking experiments (n=35), apart from pop-out effect of particular elements, the overall structure of the visual field is changed. If compared to the non-accentuated stimuli, adding single accent to both grouping and segmentation stimuli induces not only local changes in saccadic processes but also a more global difference in gaze alignment. Most importantly, accent assigns a directional effect to the visual structure, typically decreases the average fixation time (by 11-28% depending on stimuli) and changes location of fixations and decreases their variation (if compared to non-accentuated stimuli). However, no significant differences between the number of fixations in non-accentuated and accentuated stimuli can be observed