-
Frontiers in Neuroscience 2021Peripheral neuropathy can be caused by diabetes mellitus and HIV infection, and often leaves patients with treatment-resistant neuropathic pain. To better treat this...
Peripheral neuropathy can be caused by diabetes mellitus and HIV infection, and often leaves patients with treatment-resistant neuropathic pain. To better treat this condition, we need greater understanding of the pathogenesis, as well as objective biomarkers to predict treatment response. Magnetic resonance imaging (MRI) has a firm place as a biomarker for diseases of the central nervous system (CNS), but until recently has had little role for disease of the peripheral nervous system. To review the current state-of-the-art of peripheral nerve MRI in diabetic and HIV symmetrical polyneuropathy. We used systematic literature search methods to identify all studies currently published, using this as a basis for a narrative review to discuss major findings in the literature. We also assessed risk of bias, as well as technical aspects of MRI and statistical analysis. Protocol was pre-registered on NIHR PROSPERO database. MEDLINE, Web of Science and EMBASE databases were searched from 1946 to 15th August 2020 for all studies investigating either diabetic or HIV neuropathy and MRI, focusing exclusively on studies investigating symmetrical polyneuropathy. The NIH quality assessment tool for observational and cross-sectional cohort studies was used for risk of bias assessment. The search resulted in 18 papers eligible for review, 18 for diabetic neuropathy and 0 for HIV neuropathy. Risk of bias assessment demonstrated that studies generally lacked explicit sample size justifications, and some may be underpowered. Whilst most studies made efforts to balance groups for confounding variables (age, gender, BMI, disease duration), there was lack of consistency between studies. Overall, the literature provides convincing evidence that DPN is associated with larger nerve cross sectional area, T2-weighted hyperintense and hypointense lesions, evidence of nerve oedema on Dixon imaging, decreased fractional anisotropy and increased apparent diffusion coefficient compared with controls. Analysis to date is largely restricted to the sciatic nerve or its branches. There is emerging evidence that various structural MR metrics may be useful as biomarkers in diabetic polyneuropathy, and areas for future direction are discussed. Expanding this technique to other forms of peripheral neuropathy, including HIV neuropathy, would be of value. (identifier: CRD 42020167322) https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=167322.
PubMed: 34621152
DOI: 10.3389/fnins.2021.727311 -
Brain and Behavior Feb 2021To identify the most prominent and replicable fractional anisotropy (FA) alterations of white matter associated with obsessive-compulsive disorder (OCD) in tract-based... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To identify the most prominent and replicable fractional anisotropy (FA) alterations of white matter associated with obsessive-compulsive disorder (OCD) in tract-based spatial statistics (TBSS) studies.
METHODS
We reviewed previous TBSS studies (n = 20) in OCD and performed a meta-analysis (n = 16) of FA differences.
RESULTS
No between-group differences in FA were detected in the pooled meta-analysis. However, reduced FA was identified in the genu and anterior body of corpus callosum (CC) in adult OCD. FA reductions in the anterior body of CC were associated with a later age of onset in adult patients with OCD. For pediatric OCD, decreased FA in earlier adolescence and increased FA in later adolescence were seemingly related to an altered trajectory of brain maturation.
CONCLUSIONS
Absent in the pooled sample but robust in adults, disrupted microstructural organization in the anterior part of CC indicates a bias of deficits toward connections in interhemispheric connections of rostral neocortical regions, which could lead to deficits of interhemispheric communication and thus contribute to cognitive and emotional deficits in adult OCD. The correlation between FA in the anterior body of CC and older illness onset suggests that patients with later adult onset of illness may represent a biologically distinct subgroup. For pediatric OCD, alterations in neurodevelopmental maturation may contribute to inconsistent patterns of FA alteration relative to controls during adolescence. While most studies of OCD have emphasized alterations of within hemisphere fronto-striatal circuits, these results indicate that between hemisphere connectivity of this circuitry may also represent important pathophysiology of the illness.
Topics: Adolescent; Adult; Anisotropy; Brain; Child; Diffusion Tensor Imaging; Humans; Obsessive-Compulsive Disorder; White Matter
PubMed: 33270358
DOI: 10.1002/brb3.1975 -
Cancers Jun 2023Alteration in the surrounding brain tissue may occur in the presence of a brain tumor. The present study aims to assess the characteristics and criteria of the pattern... (Review)
Review
Alteration in the surrounding brain tissue may occur in the presence of a brain tumor. The present study aims to assess the characteristics and criteria of the pattern of white matter tract microstructure integrity alteration in brain tumor patients. The Scopus, PubMed/Medline, and Web of Science electronic databases were searched for related articles based on the guidelines established by PRISMA. Twenty-five studies were selected on the morphological changes of white matter tract integrity based on the differential classification of white matter tract (WMT) patterns in brain tumor patients through diffusion tensor imaging (DTI). The characterization was based on two criteria: the visualization of the tract-its orientation and position-and the DTI parameters, which were the fractional anisotropy and apparent diffusion coefficient. Individual evaluations revealed no absolute, mutually exclusive type of tumor in relation to morphological WMT microstructure integrity changes. In most cases, different types and grades of tumors have shown displacement or infiltration. Characterizing morphological changes in the integrity of the white matter tract microstructures is vital in the diagnostic and prognostic evaluation of the tumor's progression and could be a potential assessment for the early detection of possible neurological defects that may affect the patient, as well as aiding in surgery decision-making.
PubMed: 37444435
DOI: 10.3390/cancers15133326 -
Frontiers in Neurology 2020[This corrects the article DOI: 10.3389/fneur.2020.531993.].
[This corrects the article DOI: 10.3389/fneur.2020.531993.].
PubMed: 33193071
DOI: 10.3389/fneur.2020.612069 -
World Neurosurgery Aug 2021Diffusion tensor imaging (DTI) application in Chiari malformation type I (CMI) is still poorly defined. This study aimed to systematically review the literature and...
BACKGROUND
Diffusion tensor imaging (DTI) application in Chiari malformation type I (CMI) is still poorly defined. This study aimed to systematically review the literature and propose perspectives toward the clinical application of DTI in CMI.
METHODS
PubMed and Embase were searched for English-language articles published until October 20, 2020. Clinical studies and case series, evaluating fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), or radial diffusivity values in patients with CMI, were included.
RESULTS
Eight articles were included. Lower FA values were found at the syrinx level, which decreased with syrinx extent and intensity of symptoms, reflecting myelopathy severity. Decreased AD and MD in the middle cerebellar peduncles in symptomatic patients with CMI might explain the presence of cerebellar signs. Increased FA in various supratentorial structures positively correlated with pain severity. Worse performance in neuropsychological tests correlated with decreased FA, increased MD, and radial diffusivity, reflecting axonal degeneration. Postoperative FA decrease in the brainstem compression area reflects successful decompression. A positive correlation was found between the extent of tonsillar ectopia and increased FA, MD, and AD values, which could act as an early indicator of acute brainstem compression.
CONCLUSIONS
DTI might provide a valuable insight into the neurobiological foundation of symptomatic CMI presentation. The severity of white matter injury evident on DTI could serve as a reliable predictor of postoperative outcomes, therefore facilitating selection of appropriate surgical candidates. Postinterventional DTI reassessment might enable differentiation between unsuccessful surgical technique and irreversible myelopathy. The extent of tonsillar ectopia reflects the severity of microstructural brainstem injury.
Topics: Arnold-Chiari Malformation; Diffusion Tensor Imaging; Humans; Neuroimaging
PubMed: 34147690
DOI: 10.1016/j.wneu.2021.06.052 -
Progress in Neuro-psychopharmacology &... Jan 2024Cognitive impairment is a prominent feature of bipolar disorder (BD), however the neural substrates underpinning it remain unclear. Several studies have explored white...
Cognitive impairment is a prominent feature of bipolar disorder (BD), however the neural substrates underpinning it remain unclear. Several studies have explored white matter as a correlate of cognitive functioning in BD cohorts, but mixed results and varied methodologies from one to another make inferences about this relationship difficult to draw. Here we sought to systematically synthesise the findings of these studies to more clearly explicate the nature and extent of relationships between white matter and cognition in BD and determine best practice methodologies and areas for future research in this area. Using PRISMA guidelines, we identified and systematically reviewed 37 relevant studies, all of which were cross-sectional by design. There was substantial methodological heterogeneity and variability in the clinical presentations of BD cohorts encapsulated within the studies we reviewed, which complicated our synthesis of the findings. Nonetheless, there was some evidence that cognition is related to both white matter macrostructure and microstructure in people with BD. In particular, multiple microstructural studies consistently reported that higher fractional anisotropy, both globally and in the corpus callosum, associated with better complex attention skills and executive functioning. However, several reports did not identify any associations at all, and in general, associations between WM and cognition tended to only be evident in studies utilising larger samples and post-hoc selection of WM regions of interest. Further research with increased statistical power and standardised methods are required moving forward.
Topics: Humans; Bipolar Disorder; White Matter; Diffusion Tensor Imaging; Cognition; Executive Function; Anisotropy
PubMed: 37797735
DOI: 10.1016/j.pnpbp.2023.110868 -
Frontiers in Neurology 2022The patients with HIV-associated neurocognitive disorder (HAND) are often accompanied by white matter structure damage. Diffusion tensor imaging (DTI) is an important...
BACKGROUND
The patients with HIV-associated neurocognitive disorder (HAND) are often accompanied by white matter structure damage. Diffusion tensor imaging (DTI) is an important tool to detect white matter structural damage. However, the changes in DTI values reported in many studies are diverse in different white matter fiber tracts and brain regions.
PURPOSE
Our research is dedicated to evaluating the consistency and difference of the correlation between HAND and DTI measures in different studies. Additionally, the value of DTI in HAND evaluation is used to obtain consensus and independent conclusions between studies.
METHODS
We searched PubMed and Web of Science to collect relevant studies using DTI for the diagnosis of HAND. After screening and evaluating the search results, meta-analysis is used for quantitative research on data. Articles that cannot collect data but meet the research relevance will be subjected to a system review.
RESULTS
The meta-analysis shows that the HAND group has lower fractional anisotropy (standardized mean difference = -0.57 < 0.0001) and higher mean diffusivity (standardized mean difference = 0.04 < 0.0001) than the healthy control group in corpus callosum. In other white matter fibers, we found similar changes in fractional anisotropy (standardized mean difference = -1.18 < 0.0001) and mean diffusivity (standardized mean difference = 0.69 < 0.0001). However, the heterogeneity (represented by I) between the studies is high (in corpus callosum 94, 88%, in other matter fibers 95, 81%). After subgroup analysis, the heterogeneity is obtained as 19.5, 40.7% (FA, MD in corpus callosum) and 0, 0% (FA, MD among other white matter fibers).
CONCLUSION
The changes in white matter fibers in patients with HAND are statistically significant at the observation level of DTI compared with healthy people. The differences between the studies are mainly derived from demographics, start and maintenance time of antiretroviral therapy, differences in nadir CD4+T cells, and the use of different neurocognitive function scales. As an effective method to detect the changes in white matter fibers, DTI is of great significance for the diagnosis of HAND, but there are still some shortcomings. In the absence of neurocognitive function scales, independent diagnosis remains difficult. https://inplasy.com/inplasy-2021-10-0079/.
PubMed: 35873786
DOI: 10.3389/fneur.2022.898191 -
Frontiers in Endocrinology 2021Type 2 diabetes mellitus (T2DM) is often accompanied by cognitive decline and depressive symptoms. Numerous diffusion tensor imaging (DTI) studies revealed... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
Type 2 diabetes mellitus (T2DM) is often accompanied by cognitive decline and depressive symptoms. Numerous diffusion tensor imaging (DTI) studies revealed microstructural white matter (WM) abnormalities in T2DM but the findings were inconsistent. The present study aimed to conduct a coordinate-based meta-analysis (CBMA) to identify statistical consensus of DTI studies in T2DM.
METHODS
We performed a systematic search on relevant studies that reported fractional anisotropy (FA) differences between T2DM patients and healthy controls (HC). The anisotropic effect size seed-based d mapping (AES-SDM) approach was used to explore WM alterations in T2DM. A meta-regression was then used to analyze potential influences of sample characteristics on regional FA changes.
RESULTS
A total of eight studies that comprised 245 patients and 200 HC, along with 52 coordinates were extracted. The meta-analysis identified FA reductions in three clusters including the left inferior network, the corpus callosum (CC), and the left olfactory cortex. Besides, FA in the CC was negatively correlated with body mass index (BMI) in the patients group.
CONCLUSIONS
T2DM could lead to subtle WM microstructural alterations, which might be associated with cognitive deficits or emotional distress symptoms. This provides a better understanding of the pathophysiology of neurodegeneration and complications in T2DM.
SYSTEMATIC REVIEW REGISTRATION
Registered at PROSPERO (http://www.crd.york.ac.uk/PROSPERO), registration number: CRD42020218737.
Topics: Adolescent; Adult; Anisotropy; Body Mass Index; Cognition; Corpus Callosum; Diabetes Mellitus, Type 2; Diffusion Tensor Imaging; Female; Humans; Male; Middle Aged; White Matter; Young Adult
PubMed: 34012420
DOI: 10.3389/fendo.2021.658198 -
Frontiers in Neurology 2021Tourette syndrome (TS) is a neuropsychiatric disorder with multiple motor and vocal tics whose neural basis remains unclear. Diffusion tensor imaging (DTI) studies have...
Tourette syndrome (TS) is a neuropsychiatric disorder with multiple motor and vocal tics whose neural basis remains unclear. Diffusion tensor imaging (DTI) studies have demonstrated white matter microstructural alternations in TS, but the findings are inconclusive. In this study, we aimed to elucidate the most consistent white matter deficits in patients with TS. By systematically searching online databases up to December 2020 for all DTI studies comparing fractional anisotropy (FA) between patients with TS and healthy controls (HCs), we conducted anisotropic effect size-signed differential mapping (AES-SDM) meta-analysis to investigate FA differences in TS, as well as performed meta-regression analysis to explore the effects of demographics and clinical characteristics on white matter abnormalities among TS. A total of eight datasets including 168 patients with TS and 163 HCs were identified. We found that TS patients showed robustly decreased FA in the corpus callosum (CC) and right inferior longitudinal fasciculus (ILF) compared with HCs. These two regions preserved significance in the sensitivity analysis. No regions of increased FA were reported. Meta-regression analysis revealed that age, sex, tic severity, or illness duration of patients with TS were not linearly correlated with decreased FA. Patients with TS display deficits of white matter microstructure in the CC and right ILF known to be important for interhemispheric connections as well as long association fiber bundles within one hemisphere. Because the results reported in the primary literature were highly variable, future investigations with large samples would be required to support the identified white matter changes in TS.
PubMed: 34566829
DOI: 10.3389/fneur.2021.659250 -
Drug and Alcohol Dependence Aug 2019Converging lines of evidence from diffusion tensor imaging (DTI) studies reveal significant alterations in white matter (WM) microstructure in the prefrontal cortex of... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Converging lines of evidence from diffusion tensor imaging (DTI) studies reveal significant alterations in white matter (WM) microstructure in the prefrontal cortex of chronic stimulant users compared to controls, suggesting compromised axonal microstructure and/or myelin.
METHODS
A meta-analysis of DTI-based WM integrity was conducted for white matter regions across the corpus callosum and association fibers. Articles were sourced and selected using PRISMA guidelines for systematic review and meta-analysis. Inclusion and exclusion criteria were determined by the authors in order to best capture WM integrity among individuals with primary stimulant use in comparison to healthy control subjects.
RESULTS
Eleven studies that focused on region-of-interest (ROI)-based analysis of WM integrity were extracted from an initial pool of 113 independent studies. Analysis across ROIs indicated significantly lower fractional anisotropy (FA) values in stimulant use groups compared to controls with a small to moderate overall effect (Hedges' g = -0.37, 95% CI [-0.54, -0.20]). Eigenvalues were also analyzed, revealing a significant effect for radial diffusivity (RD; Hedges' g = 0.24, 95% CI [0.01, 0.47]) but not axial diffusivity (AD; Hedges' g = 0.05, 95% CI [-0.20, 0.29]) or mean diffusivity (MD; Hedges' g = 0.20, 95% CI [-0.01, 0.41]). Subgroup analyses based on specific ROIs, primary substance use, poly-substance use, and imaging technology were also explored.
CONCLUSION
Results of the present study suggest a consistent effect of compromised WM integrity for individuals with stimulant use disorders. Furthermore, no significant differences were found between cocaine and methamphetamine-based groups.
Topics: Adult; Amphetamine-Related Disorders; Anisotropy; Central Nervous System Stimulants; Corpus Callosum; Diffusion Tensor Imaging; Female; Humans; Male; Prefrontal Cortex; White Matter
PubMed: 31176066
DOI: 10.1016/j.drugalcdep.2019.03.023