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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 -
Brain and Behavior Jul 2022Numerous cortical and subcortical structures have been studied extensively concerning alterations of their integrity as well as their neurotransmitters in depression.... (Review)
Review
BACKGROUND
Numerous cortical and subcortical structures have been studied extensively concerning alterations of their integrity as well as their neurotransmitters in depression. However, connections between these structures have received considerably less attention.
OBJECTIVE
This systematic review presents results from recent neuroimaging as well as neuropathologic studies conducted on humans and other mammals. It aims to provide evidence for impaired white matter integrity in individuals expressing a depressive phenotype.
METHODS
A systematic database search in accordance with the PRISMA guidelines was conducted to identify imaging and postmortem studies conducted on humans with a diagnosis of major depressive disorder, as well as on rodents and primates subjected to an animal model of depression.
RESULTS
Alterations are especially apparent in frontal gyri, as well as in structures establishing interhemispheric connectivity between frontal regions. Translational neuropathological findings point to alterations in oligodendrocyte density and morphology, as well as to alterations in the expression of genes related to myelin synthesis. An important role of early life adversities in the development of depressive symptoms and white matter alterations across species is thereby revealed. Data indicating that stress can interfere with physiological myelination patterns is presented. Altered myelination is most notably present in regions that are subject to maturation during the developmental stage of exposure to adversities.
CONCLUSION
Translational studies point to replicable alterations in white matter integrity in subjects suffering from depression across multiple species. Impaired white matter integrity is apparent in imaging as well as neuropathological studies. Future studies should focus on determining to what extent influencing white matter integrity is able to improve symptoms of depression in animals as well as humans.
Topics: Anisotropy; Brain; Depression; Depressive Disorder, Major; Diffusion Tensor Imaging; Humans; White Matter
PubMed: 35652161
DOI: 10.1002/brb3.2629 -
Biology Mar 2023Diffusion tensor imaging (DTI) is gaining traction in neuroscience research as a tool for evaluating neural fibers. The technique can be used to assess white matter (WM)... (Review)
Review
Diffusion tensor imaging (DTI) is gaining traction in neuroscience research as a tool for evaluating neural fibers. The technique can be used to assess white matter (WM) microstructure in neurodegenerative disorders, including Parkinson disease (PD). There is evidence that the uncinate fasciculus and the cingulum bundle are involved in the pathogenesis of PD. These fasciculus and bundle alterations correlate with the symptoms and stages of PD. PRISMA 2022 was used to search PubMed and Scopus for relevant articles. Our search revealed 759 articles. Following screening of titles and abstracts, a full-text review, and implementing the inclusion criteria, 62 papers were selected for synthesis. According to the review of selected studies, WM integrity in the uncinate fasciculus and cingulum bundles can vary according to symptoms and stages of Parkinson disease. This article provides structural insight into the heterogeneous PD subtypes according to their cingulate bundle and uncinate fasciculus changes. It also examines if there is any correlation between these brain structures' structural changes with cognitive impairment or depression scales like Geriatric Depression Scale-Short (GDS). The results showed significantly lower fractional anisotropy values in the cingulum bundle compared to healthy controls as well as significant correlations between FA and GDS scores for both left and right uncinate fasciculus regions suggesting that structural damage from disease progression may be linked to cognitive impairments seen in advanced PD patients. This review help in developing more targeted treatments for different types of Parkinson's disease, as well as providing a better understanding of how cognitive impairments may be related to these structural changes. Additionally, using DTI scans can provide clinicians with valuable information about white matter tracts which is useful for diagnosing and monitoring disease progression over time.
PubMed: 36979166
DOI: 10.3390/biology12030475 -
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 -
Journal of Neurotrauma Nov 2021Diffusion tensor imaging (DTI) of brain white matter (WM) may be useful for characterizing the nature and degree of brain injury after sport-related concussion (SRC) and...
Diffusion tensor imaging (DTI) of brain white matter (WM) may be useful for characterizing the nature and degree of brain injury after sport-related concussion (SRC) and assist in establishing objective diagnostic and prognostic biomarkers. This study aimed to conduct a systematic review using an quality rating strategy to determine the most consistent DTI-WM changes post-SRC. Articles published in English (until June 2020) were retrieved by standard research engine and gray literature searches ( = 4932), using PRISMA guidelines. Eligible studies were non-interventional naturalistic original studies that conducted DTI within 6 months of SRC in current athletes from all levels of play, types of sports, and sex. A total of 29 articles were included in the review, and after quality appraisal by two raters, data from 10 studies were extracted after being identified as high quality. High-quality studies showed widespread moderate-to-large WM differences when SRC samples were compared to controls during the acute to early chronic stage (days to weeks) post-SRC, including both increased and decreased fractional anisotropy and axial diffusivity and decreased mean diffusivity and radial diffusivity. WM differences remained stable in the chronic stage (2-6 months post-SRC). DTI metrics were commonly associated with SRC symptom severity, although standardized SRC diagnostics would improve future research. This indicates that microstructural recovery is often incomplete at return to play and may lag behind clinically assessed recovery measures. Future work should explore interindividual trajectories to improve understanding of the heterogeneous and dynamic WM patterns post-SRC.
Topics: Athletic Injuries; Brain Concussion; Diffusion Tensor Imaging; Humans; White Matter
PubMed: 34309410
DOI: 10.1089/neu.2021.0154 -
European Journal of Radiology Feb 2022This study aimed to review diffusion tensor imaging studies of mild traumatic brain injury (mTBI) in adults with longitudinal acquisition of data and investigate the... (Review)
Review
PURPOSE
This study aimed to review diffusion tensor imaging studies of mild traumatic brain injury (mTBI) in adults with longitudinal acquisition of data and investigate the variability of findings in association with related factors, such as the time post-injury.
METHODS
Eligible studies from PubMed and EMBASE were searched to identify relevant studies for review. Of the 540 studies, 23 observational studies without intervention and with the following characteristics were included: original research in which adults with mTBI were examined, diffusion tensor imaging was acquired at least twice, white matter integrity was investigated by estimating diffusion metrics, and mode of injury was not restricted to sport- or blast-related mTBI.
RESULTS
Baseline scans were acquired within 3 weeks post-injury, followed by longitudinal scans within 3 months and at 12 months post-injury. During the acute/subacute period, mixed results (increase, decrease, or no significant change) of fractional anisotropy (FA) were observed compared to those in controls. Some studies reported increased FA during the acute/subacute period compared to controls, followed by normalization of FA. Decreased FA was also reported during the acute/subacute period, which lasted long into the chronic phase. In the acute phase, the mean diffusivity (MD) was greater than that in the controls. Compared to the early phase of injury, MD was reduced in the follow-up phase in most studies in the mTBI group. Insignificant differences in FA and MD have been reported in several studies. Such variability limits the clinical usefulness of diffusion tensor metrics.
CONCLUSIONS
There was a high variability in reported changes in white matter integrity. Decreased FA not only in acute/subacute but also in long-term period after injury may indicate long-term neurodegenerative processes after mTBI. Nevertheless, longitudinal changes in MD towards normalization suggest possible recovery. Long-term cohort studies with research initiatives should be considered to elucidate brain changes after mTBI.
Topics: Adult; Anisotropy; Brain; Brain Concussion; Diffusion Tensor Imaging; Humans; White Matter
PubMed: 34973540
DOI: 10.1016/j.ejrad.2021.110117 -
Journal of Affective Disorders Apr 2024Social anxiety disorder (SAD) is a psychiatric condition characterized by impaired social functioning that negatively impacts individuals' quality of life. Previous... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Social anxiety disorder (SAD) is a psychiatric condition characterized by impaired social functioning that negatively impacts individuals' quality of life. Previous neuroimaging studies have revealed morphological and functional changes in various brain regions associated with SAD. Recent advances in diffusion tensor imaging (DTI) and diffusion-weighted imaging (DWI) have enabled the investigation of microstructural white matter (WM) alterations in SAD. This study aims to provide an overview of DTI/DWI studies exploring WM microstructure changes in SAD.
METHODS
A systematic search on PubMed, Scopus, Web of Science, and PsycINFO was conducted for relevant records on July 8, 2023. An exploratory meta-analysis was also performed.
RESULTS
Eight studies were reviewed. Consistent findings indicated reduced fractional anisotropy and increased diffusivity measures in different WM tracts in SAD patients compared to healthy controls. These alterations were mostly observed within regions of the fronto-limbic network, like uncinate fasciculus (UF) and superior and inferior longitudinal fasciculi (SLF and ILF). Finally, our exploratory meta-analysis on four studies utilizing a voxel-wise analytic approach yielded no significant differences between SAD patients and controls.
LIMITATIONS
Limited number of studies, small sample sizes, and heterogeneity in analysis methods.
CONCLUSIONS
Patients with SAD exhibited altered WM integrity, particularly in the UF, SLF, and ILF, compared to healthy controls. However, due to the limited number of included studies, our meta-analysis yielded no significant differences between SAD patients and controls. Therefore, future research is crucial to unravel the link between altered WM structure and the involvement of other limbic and cortical structures in SAD pathogenesis.
Topics: Humans; White Matter; Phobia, Social; Diffusion Tensor Imaging; Quality of Life; Brain; Anisotropy
PubMed: 38220105
DOI: 10.1016/j.jad.2024.01.118 -
Frontiers in Endocrinology 2023The diversity of clinical trajectories in diabetic kidney disease (DKD) has made blood and biochemical urine markers less precise, while renal puncture, the gold... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The diversity of clinical trajectories in diabetic kidney disease (DKD) has made blood and biochemical urine markers less precise, while renal puncture, the gold standard, is almost impossible in the assessment of diabetic kidney disease, and the value of functional magnetic resonance imaging in the evaluation of diabetic pathological alterations is increasingly recognized.
METHODS
The literature on functional magnetic resonance imaging (fMRI) for the assessment of renal alterations in diabetic kidney disease was searched in PubMed, Web of Science, Cochrane Library, and Embase databases. The search time limit is from database creation to March 10, 2023. RevMan was used to perform a meta-analysis of the main parameters of fMRIs extracted from DKD patients and healthy volunteers (HV).
RESULTS
24 publications (1550 subjects) were included in this study, using five functional MRIs with seven different parameters. The renal blood flow (RBF) values on Arterial spin labeling magnetic resonance imaging (ASL-MRI) was significantly lower in the DKD group than in the HV group. The [WMD=-99.03, 95% CI (-135.8,-62.27), <0.00001]; Diffusion tensor imaging magnetic resonance imaging (DTI-MRI) showed that the fractional anisotropy (FA) values in the DKD group were significantly lower than that in HV group [WMD=-0.02, 95%CI (-0.03,-0.01), <0.0001]. And there were no statistically significant differences in the relevant parameters in Blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) or Intro-voxel incoherent movement magnetic resonance imaging (IVIM-DWI).
DISCUSSION
ASL and DWI can identify the differences between DKD and HV. DTI has a significant advantage in assessing renal cortical changes; IVIM has some value in determining early diabetic kidney disease from the cortex or medulla. We recommend combining multiple fMRI parameters to assess structural or functional changes in the kidney to make the assessment more comprehensive. We did not observe a significant risk of bias in the present study.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk, identifier CRD42023409249.
Topics: Magnetic Resonance Imaging; Diabetic Neuropathies; Diffusion Tensor Imaging; Kidney; Diabetes Mellitus
PubMed: 37484949
DOI: 10.3389/fendo.2023.1226830 -
Journal of Psychiatric Research Mar 2022Neuropsychiatric disorders including generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), major depressive disorder (MDD), bipolar disorder (BD), and... (Review)
Review
Neuropsychiatric disorders including generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ) have been considered distinct categories of diseases despite their overlapping characteristics and symptomatology. We aimed to provide an in-depth review elucidating the role of glutamate/Glx and white matter (WM) abnormalities in these disorders from a transdiagnostic perspective. The PubMed online database was searched for studies published between 2010 and 2021. After careful screening, 401 studies were included. The findings point to decreased levels of glutamate in the Anterior Cingulate Cortex in both SZ and BD, whereas Glx is elevated in the Hippocampus in SZ and MDD. With regard to WM abnormalities, the Corpus Callosum and superior Longitudinal Fascicle were the most consistently identified brain regions showing decreased fractional anisotropy (FA) across all the reviewed disorders, except GAD. Additionally, the Uncinate Fasciculus displayed decreased FA in all disorders, except OCD. Decreased FA was also found in the inferior Longitudinal Fasciculus, inferior Fronto-Occipital Fasciculus, Thalamic Radiation, and Corona Radiata in SZ, BD, and MDD. Decreased FA in the Fornix and Corticospinal Tract were found in BD and SZ patients. The Cingulum and Anterior Limb of Internal Capsule exhibited decreased FA in MDD and SZ patients. The results suggest a gradual increase in severity from GAD to SZ defined by the number of brain regions with WM abnormality which may be partially caused by abnormal glutamate levels. WM damage could thus be considered a potential marker of some of the main neuropsychiatric disorders.
Topics: Anisotropy; Bipolar Disorder; Brain; Depressive Disorder, Major; Diffusion Tensor Imaging; Glutamic Acid; Humans; White Matter
PubMed: 35151030
DOI: 10.1016/j.jpsychires.2021.12.042 -
Frontiers in Oncology 2019Controversy still exists on the diagnosability of diffusion tensor imaging (DTI) for breast lesions characterization across published studies. The clinical guideline of...
Controversy still exists on the diagnosability of diffusion tensor imaging (DTI) for breast lesions characterization across published studies. The clinical guideline of DTI used in the breast has not been established. This meta-analysis aims to pool relevant evidences and evaluate the diagnostic performance of DTI in the differential diagnosis of malignant and benign breast lesions. The studies that assessed the diagnostic performance of DTI parameters in the breast were searched in Embase, PubMed, and Cochrane Library between January 2010 and September 2019. Standardized mean differences and 95% confidence intervals of fractional anisotropy (FA), mean diffusivity (MD), and three diffusion eigenvalues (λ1, λ2, and λ3) were calculated using Review Manager 5.2. The pooled sensitivity, specificity, and area under the curve (AUC) were calculated with a bivariate model. Publication bias and heterogeneity between studies were also assessed using Stata 12.0. Sixteen eligible studies incorporating 1,636 patients were included. The standardized mean differences indicated that breast cancers had a significantly higher FA but lower MD, λ1, λ2, and λ3 than those of benign lesions (all < 0.05). Subgroup analysis indicated that invasive breast carcinoma (IBC) had a significantly lower MD value than that of ductal carcinoma (DCIS) ( = 0.02). λ1 showed the best diagnostic accuracy with pooled sensitivity, specificity, and AUC of 93%, 92%, and 0.97, followed by MD (AUC = 0.92, sensitivity = 87%, specificity = 83%) and FA (AUC = 0.76, sensitivity = 70%, specificity = 70%) in the differential diagnosis of breast lesions. DTI with multiple quantitative parameters was adequate to differentiate breast cancers from benign lesions based on their biological characteristics. MD can further distinguish IBC from DCIS. The parameters, especially λ1 and MD, should attract our attention in clinical practice.
PubMed: 31803615
DOI: 10.3389/fonc.2019.01229