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Global Spine Journal Jun 2024Systematic review.
STUDY DESIGN
Systematic review.
OBJECTIVE
Degenerative cervical myelopathy (DCM) is a common spinal cord disorder necessitating surgery. We aim to explore how effectively diffusion tensor imaging (DTI) can distinguish DCM from healthy individuals and assess the relationship between DTI metrics and symptom severity.
METHODS
We included studies with adult DCM patients who had not undergone decompressive surgery and implemented correlation analyses between DTI parameters and severity, or compared healthy controls and DCM patients.
RESULTS
57 studies were included in our meta-analysis. At the maximal compression (MC) level, fractional anisotropy (FA) exhibited lower values in DCM patients, while apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) were notably higher in the DCM group. Moreover, our investigation into the diagnostic utility of DTI parameters disclosed high sensitivity, specificity, and area under the curve values for FA (.84, .80, .83 respectively) and ADC (.74, .84, .88 respectively). Additionally, we explored the correlation between DTI parameters and myelopathy severity, revealing a significant correlation of FA (.53, 95% CI:0.40 to .65) at MC level with JOA/mJOA scores.
CONCLUSION
Current guidelines for DCM suggest decompressive surgery for both mild and severe cases. However, they lack clear recommendations on which mild DCM patients might benefit from conservative treatment vs immediate surgery. ADC's role here could be pivotal, potentially differentiating between healthy individuals and DCM. While it may not correlate with symptom severity, it might predict surgical outcomes, making it a valuable imaging biomarker for clearer management decisions in mild DCM.
PubMed: 38877604
DOI: 10.1177/21925682241263792 -
JAACAP Open Dec 2023A growing body of literature has focused on the neural mechanisms of depression. Our goal was to conduct a systematic review on the white matter microstructural...
OBJECTIVE
A growing body of literature has focused on the neural mechanisms of depression. Our goal was to conduct a systematic review on the white matter microstructural differences in adolescents with depressive disorders vs adolescents without depressive disorders.
METHOD
We searched PubMed and PsycINFO for publications on August 3, 2022 (original search conducted in July 2021). The review was registered on PROSPERO (registration number: CRD42021268200), and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Eligible studies were original research papers comparing diffusion tensor/spectrum imaging findings in adolescents with vs without depression (originally ages 12-19 years, later expanded to 11-21 years). Studies were excluded if they focused on depression exclusively in the context of another condition, used only dimensional depressive symptom assessment(s), or used the same dataset as another included publication.
RESULTS
The search yielded 575 unique records, of which 14 full-text papers were included (824 adolescents with depression and 686 without depression). The following white matter regions showed significant differences in fractional anisotropy in at least 3 studies: uncinate fasciculus, cingulum, anterior corona radiata, inferior fronto-occipital fasciculus, and corpus callosum (genu and body). Most studies reported decreased, rather than increased, fractional anisotropy in adolescents with depression. Limitations include the possibility for selective reporting bias and risk of imprecision, given the small sample sizes in some studies.
CONCLUSION
Our systematic review suggests aberrant white matter microstructure in limbic-cortical-striatal-thalamic circuits, and the corpus callosum, in adolescents with depression. Future research should focus on developmental trajectories in depression, identifying sources of heterogeneity and integrating findings across imaging modalities.
PubMed: 38576601
DOI: 10.1016/j.jaacop.2023.08.006 -
CNS Neuroscience & Therapeutics Feb 2024Amyotrophic lateral sclerosis (ALS) is a progressive motor and extra-motor neurodegenerative disease. This systematic review aimed to examine MRI biomarkers and... (Review)
Review
BACKGROUND AND OBJECTIVE
Amyotrophic lateral sclerosis (ALS) is a progressive motor and extra-motor neurodegenerative disease. This systematic review aimed to examine MRI biomarkers and neuropsychological assessments of the hippocampal and parahippocampal regions in patients with ALS.
METHODS
A systematic review was conducted in the Scopus and PubMed databases for studies published between January 2000 and July 2023. The inclusion criteria were (1) MRI studies to assess hippocampal and parahippocampal regions in ALS patients, and (2) studies reporting neuropsychological data in patients with ALS.
RESULTS
A total of 46 studies were included. Structural MRI revealed hippocampal atrophy, especially in ALS-FTD, involving specific subregions (CA1, dentate gyrus). Disease progression and genetic factors impacted atrophy patterns. Diffusion tensor imaging (DTI) showed increased mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and decreased fractional anisotropy (FA) in the hippocampal tracts and adjacent regions, indicating loss of neuronal and white matter integrity. Functional MRI (fMRI) revealed reduced functional connectivity (FC) between the hippocampus, parahippocampus, and other regions, suggesting disrupted networks. Perfusion MRI showed hypoperfusion in parahippocampal gyri. Magnetic resonance spectroscopy (MRS) found changes in the hippocampus, indicating neuronal loss. Neuropsychological tests showed associations between poorer memory and hippocampal atrophy or connectivity changes. CA1-2, dentate gyrus, and fimbria atrophy were correlated with worse memory.
CONCLUSIONS
The hippocampus and the connected regions are involved in ALS. Hippocampal atrophy disrupted connectivity and metabolite changes correlate with cognitive and functional decline. Specific subregions can be particularly affected. The hippocampus is a potential biomarker for disease monitoring and prognosis.
Topics: Humans; Diffusion Tensor Imaging; Amyotrophic Lateral Sclerosis; Neurodegenerative Diseases; Frontotemporal Dementia; Magnetic Resonance Imaging; Hippocampus; Biomarkers; Neuropsychological Tests; Atrophy
PubMed: 38334254
DOI: 10.1111/cns.14578 -
GeroScience Apr 2024In the context of a globally aging population, exploring interventions that counteract age-related cognitive decline and cerebral structural alterations is paramount.... (Meta-Analysis)
Meta-Analysis
In the context of a globally aging population, exploring interventions that counteract age-related cognitive decline and cerebral structural alterations is paramount. Among various strategies, physical exercise (PE) emerges as a prevalent activity routinely incorporated in many individuals' lives. This systematic review and meta-analysis aims to elucidate the impact of PE on white matter (WM) integrity and cognitive function in older adults. Data from 581 participants, 312 in the PE intervention group, and 269 in the control group were extracted from nine randomized controlled trials (RCTs) retrieved from databases including PubMed, Embase, Web of Science, and the Cochrane Library. The results indicated a significant improvement in white matter (WM) integrity in individuals engaged in PE, as evidenced by enhanced fractional anisotropy (FA) scores (SMD = 0.4, 95% confidence interval (CI) [0.05, 0.75], P = 0.024). The GRADE assessment revealed a moderate risk. However, no significant associations were found between PE and other metrics such as radial diffusivity (RD), mean diffusivity (MD), white matter volume (WMV), hippocampal volume (HV), and cognitive functions (executive function [EF], memory, processing speed). In conclusion, our study emphasizes the potential neurostructural and cognitive functional benefits of physical exercise for the brain health of older adults.
Topics: Humans; Aged; White Matter; Diffusion Tensor Imaging; Cognition; Brain; Exercise
PubMed: 38108993
DOI: 10.1007/s11357-023-01033-8 -
The Indian Journal of Radiology &... Oct 2023High-grade gliomas (HGGs) are the most prevalent primary malignancy of the central nervous system. The tumor results in vasogenic and infiltrative edema . Exact... (Review)
Review
High-grade gliomas (HGGs) are the most prevalent primary malignancy of the central nervous system. The tumor results in vasogenic and infiltrative edema . Exact anatomical differentiation of these edemas is so important for surgical planning. Multimodal imaging could be used to differentiate the edema type. The aim of this study was to investigate the role of multimodal imaging in the differentiation of vasogenic edema from infiltrative edema in patients with HGG (grade III and grade IV). A search on PubMed, EMBASE, Scopus, and ISI Web of Science Core Collection up to June 2022 using terms related to (a) multimodal imaging AND (b) HGG AND (c) edema. (PROSPERO registration number: CRD42022336131) Two reviewers screened the articles and independently extracted the data. We included original articles assessing the role of multimodal imaging in differentiating vasogenic from infiltrative edema in patients with HGG. Six high-quality articles remained for the narrative synthesis. Dynamic susceptibility contrast imaging showed that relative cerebral blood volume and relative cerebral blood flow were higher in the infiltrative edema component than in the vasogenic edema component. Diffusion tensor imaging revealed a dispute on fractional anisotropy. The apparent diffusion coefficient was comparable between the two edematous components. Magnetic resonance spectroscopy exhibited an increment in choline/creatinine ratio and choline/N-acetyl aspartate ratio in the infiltrative edema component. Strict study selection, low sample size of relevant published studies, and heterogeneity in endpoint variables were the major drawbacks. Multimodal imaging, including dynamic susceptibility contrast and magnetic resonance spectroscopy, might help differentiate between vasogenic and infiltrative edema.
PubMed: 37811185
DOI: 10.1055/s-0043-1772466 -
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 Psychology 2023Diffusion Tensor Imaging (DTI) indicators of different white matter (WM) fibers and brain region lesions for post-stroke aphasia (PSA) are inconsistent in existing...
INTRODUCTION
Diffusion Tensor Imaging (DTI) indicators of different white matter (WM) fibers and brain region lesions for post-stroke aphasia (PSA) are inconsistent in existing studies. Our study examines the consistency and differences between PSA tests performed with DTI. In addition, obtaining consistent and independent conclusions between studies was made possible by utilizing DTI in PSA assessment.
METHODS
In order to gather relevant studies using DTI for diagnosing PSA, we searched the Web of Science, PubMed, Embase, and CNKI databases. Based on the screening and evaluation of the included studies, the meta-analysis was used to conduct a quantitative analysis. Narrative descriptions were provided for studies that met the inclusion criteria but lacked data.
RESULTS
First, we reported on the left hemisphere. The meta-analysis showed that fractional anisotropy (FA) of the arcuate fasciculus (AF) and superior longitudinal fasciculus (SLF), inferior frontal-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), and uncinate fasciculus (UF) were decreased in the PSA group in comparison with the healthy controls ( < 0.00001). However, in the comparison of axial diffusivity (AD), there was no statistically significant difference in white matter fiber tracts in the dual-stream language model of the PSA group. Elevated radial diffusivity (RD) was seen only in the IFOF and ILF ( = 0.01; = 0.05). In the classic Broca's area, the FA of the PSA group was decreased ( < 0.00001) while the apparent diffusion coefficient was elevated ( = 0.03). Secondly, we evaluated the white matter fiber tracts in the dual-stream language model of the right hemisphere. The FA of the PSA group was decreased only in the IFOF ( = 0.001). AD was elevated in the AF and UF ( < 0.00001; PUF = 0.009). RD was elevated in the AF and UF ( = 0.01; = 0.003). The other fiber tracts did not undergo similar alterations.
CONCLUSION
In conclusion, DTI is vital for diagnosing PSA because it detects WM changes effectively, but it still has some limitations. Due to a lack of relevant language scales and clinical manifestations, diagnosing and differentiating PSA independently remain challenging.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=365897.
PubMed: 37790217
DOI: 10.3389/fpsyg.2023.1140588 -
Magnetic Resonance Imaging Dec 2023Multiple sclerosis (MS), namely the phenotype of the relapsing-remitting form, is the most common white matter disease and is mostly characterized by demyelination and... (Review)
Review
Multiple sclerosis (MS), namely the phenotype of the relapsing-remitting form, is the most common white matter disease and is mostly characterized by demyelination and inflammation, which lead to neurodegeneration and cognitive decline. Its diagnosis and monitoring are performed through conventional structural MRI, in which T2-hyperintense lesions can be identified, but this technique lacks sensitivity and specificity, mainly in detecting damage to normal appearing tissues. Models of diffusion-weighted MRI such as diffusion-tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) allow to uncover microstructural abnormalities that occur in MS, mainly in normal appearing tissues such as the normal appearing white matter (NAWM), which allows to overcome limitations of conventional MRI. DTI is the standard method used for modelling this kind of data, but it has limitations, which can be tackled by using more complex diffusion models, such as NODDI, which provides additional information on morphological properties of tissues. Although there are several studies in MS using both diffusion models, there is no formal assessment that summarizes the findings of both methods in lesioned and normal appearing tissues, and whether one is more advantageous than the other. Hence, this systematic review aims to identify what microstructural abnormalities are seen in lesions and/or NAWM in relapsing-remitting MS while using two different approaches to modelling diffusion data, namely DTI and NODDI, and if one of them is more appropriate than the other or if they are complementary to each other. The search was performed using PubMed, which was last searched on November 2022, and aimed at finding studies that either utilized both DTI and NODDI in the same dataset, or only one of the methods. Eleven articles were included in this review, which included cohorts with a relatively low sample size (total number of patients = 254, total number of healthy controls = 240), and patients with a moderate disease duration, all with relapsing-remitting MS. Overall, studies found decreased fractional anisotropy (FA), neurite density index (NDI) and orientation dispersion index (ODI), and increased mean, axial and radial diffusivities (MD, AD and RD, respectively) in lesions, when compared to contralateral NAWM and healthy controls' white matter. Compared to healthy controls' white matter, NAWM showed lower FA and NDI and higher MD, AD, RD, and ODI. Results from the included articles confirm that there is active demyelination and inflammation in both lesions and NAWM, as well as loss in neurites, and that structural damage is not confined to focal lesions, which is in concordance with histological findings and results from other imaging techniques. Furthermore, NODDI is suggested to have higher sensitivity and specificity, as seen by inspecting imaging results, compared to DTI, while still being clinically feasible. The use of biomarkers derived from such advanced diffusion models in clinical practice could imply a better understanding of treatment efficacy and disease progression, without relying on the manifestation of clinical symptoms, such as relapses.
Topics: Humans; Multiple Sclerosis; Diffusion Tensor Imaging; Diffusion Magnetic Resonance Imaging; White Matter; Brain; Neurites; Image Processing, Computer-Assisted
PubMed: 37775062
DOI: 10.1016/j.mri.2023.09.010 -
Frontiers in Neuroimaging 2023Cannabis is the most widely used regulated substance by youth and adults. Cannabis use has been associated with psychosocial problems, which have been partly ascribed to...
INTRODUCTION
Cannabis is the most widely used regulated substance by youth and adults. Cannabis use has been associated with psychosocial problems, which have been partly ascribed to neurobiological changes. Emerging evidence to date from diffusion-MRI studies shows that cannabis users compared to controls show poorer integrity of white matter fibre tracts, which structurally connect distinct brain regions to facilitate neural communication. However, the most recent evidence from diffusion-MRI studies thus far has yet to be integrated. Therefore, it is unclear if white matter differences in cannabis users are evident consistently in selected locations, in specific diffusion-MRI metrics, and whether these differences in metrics are associated with cannabis exposure levels.
METHODS
We systematically reviewed the results from diffusion-MRI imaging studies that compared white matter differences between cannabis users and controls. We also examined the associations between cannabis exposure and other behavioral variables due to changes in white matter. Our review was pre-registered in PROSPERO (ID: 258250; https://www.crd.york.ac.uk/prospero/).
RESULTS
We identified 30 diffusion-MRI studies including 1,457 cannabis users and 1,441 controls aged 16-to-45 years. All but 6 studies reported group differences in white matter integrity. The most consistent differences between cannabis users and controls were lower fractional anisotropy within the arcuate/superior longitudinal fasciculus (7 studies), and lower fractional anisotropy of the corpus callosum (6 studies) as well as higher mean diffusivity and trace (4 studies). Differences in fractional anisotropy were associated with cannabis use onset (4 studies), especially in the corpus callosum (3 studies).
DISCUSSION
The mechanisms underscoring white matter differences are unclear, and they may include effects of cannabis use onset during youth, neurotoxic effects or neuro adaptations from regular exposure to tetrahydrocannabinol (THC), which exerts its effects by binding to brain receptors, or a neurobiological vulnerability predating the onset of cannabis use. Future multimodal neuroimaging studies, including recently developed advanced diffusion-MRI metrics, can be used to track cannabis users over time and to define with precision when and which region of the brain the white matter changes commence in youth cannabis users, and whether cessation of use recovers white matter differences.
SYSTEMATIC REVIEW REGISTRATION
www.crd.york.ac.uk/prospero/, identifier: 258250.
PubMed: 37554654
DOI: 10.3389/fnimg.2023.1129587 -
BMC Ophthalmology Aug 2023Thyroid eye disease is an extrathyroidal manifestation of Graves' disease and is associated with dry eye disease. This is the first systematic review and meta-analysis... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Thyroid eye disease is an extrathyroidal manifestation of Graves' disease and is associated with dry eye disease. This is the first systematic review and meta-analysis to evaluate the role of magnetic resonance imaging lacrimal gland parameters in thyroid eye disease diagnosis, activity grading, and therapeutic responses prediction.
METHODS
Up to 23 August, 2022, 504 studies from PubMed and Cochrane Library were analyzed. After removing duplicates and imposing selection criteria, nine eligible studies were included. Risk of bias assessment was done. Meta-analyses were performed using random-effect model if heterogeneity was significant. Otherwise, fixed-effect model was used. Main outcome measures include seven structural magnetic resonance imaging parameters (lacrimal gland herniation, maximum axial area, maximum coronal area, maximum axial length, maximum coronal length, maximum axial width, maximum coronal width), and three functional magnetic resonance imaging parameters (diffusion tensor imaging-fractional anisotropy, diffusion tensor imaging-apparent diffusion coefficient or mean diffusivity, diffusion-weighted imaging-apparent diffusion coefficient).
RESULTS
Thyroid eye disease showed larger maximum axial area, maximum coronal area, maximum axial length, maximum axial width, maximum coronal width, diffusion tensor imaging-apparent diffusion coefficient/ mean diffusivity, and lower diffusion tensor imaging-fractional anisotropy than controls. Active thyroid eye disease showed larger lacrimal gland herniation, maximum coronal area, diffusion-weighted imaging-apparent diffusion coefficient than inactive. Lacrimal gland dimensional (maximum axial area, maximum coronal area, maximum axial length, maximum axial width, maximum coronal width) and functional parameters (diffusion tensor imaging-apparent diffusion coefficient, diffusion tensor imaging-apparent diffusion coefficient) could be used for diagnosing thyroid eye disease; lacrimal gland herniation, maximum coronal area, and diffusion-weighted imaging-apparent diffusion coefficient for differentiating active from inactive thyroid eye disease; diffusion tensor imaging parameters (diffusion tensor imaging-fractional anisotropy, diffusion tensor imaging-mean diffusivity) and lacrimal gland herniation for helping grading and therapeutic responses prediction respectively.
CONCLUSIONS
Magnetic resonance imaging lacrimal gland parameters can detect active thyroid eye disease and differentiate thyroid eye disease from controls. Maximum coronal area is the most effective indicator for thyroid eye disease diagnosis and activity grading. There are inconclusive results showing whether structural or functional lacrimal gland parameters have diagnostic superiority. Future studies are warranted to determine the use of magnetic resonance imaging lacrimal gland parameters in thyroid eye disease.
Topics: Humans; Graves Ophthalmopathy; Lacrimal Apparatus; Diffusion Tensor Imaging; Magnetic Resonance Imaging; Outcome Assessment, Health Care
PubMed: 37550660
DOI: 10.1186/s12886-023-03008-x