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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 Human Neuroscience 2021Swallowing disorders (dysphagia) can negatively impact quality of life and health. For clinicians and researchers seeking to improve outcomes for patients with...
Swallowing disorders (dysphagia) can negatively impact quality of life and health. For clinicians and researchers seeking to improve outcomes for patients with dysphagia, understanding the neural control of swallowing is critical. The role of gray matter in swallowing control has been extensively documented, but knowledge is limited regarding the contributions of white matter. Our aim was to identify, evaluate, and summarize the populations, methods, and results of published articles describing the role of white matter in neural control of swallowing. We completed a systematic review with a multi-engine search following PRISMA-P 2015 standards. Two authors screened articles and completed blind full-text review and quality assessments using an adapted U.S. National Institute of Health's Quality Assessment. The senior author resolved any disagreements. Qualitative synthesis of evidence was completed. The search yielded 105 non-duplicate articles, twenty-two of which met inclusion criteria. Twenty were rated as Good (5/22; 23%) or Fair (15/22; 68%) quality. Stroke was the most represented diagnosis ( = 20; 91%). All studies were observational, and half were retrospective cohort design. The majority of studies (13/22; 59%) quantified white matter damage with lesion-based methods, whereas 7/22 (32%) described intrinsic characteristics of white matter using methods like fractional anisotropy. Fifteen studies (68%) used instrumental methods for swallowing evaluations. White matter areas commonly implicated in swallowing control included the pyramidal tract, internal capsule, corona radiata, superior longitudinal fasciculus, external capsule, and corpus callosum. Additional noteworthy themes included: severity of white matter damage is related to dysphagia severity; bilateral white matter lesions appear particularly disruptive to swallowing; and white matter adaptation can facilitate dysphagia recovery. Gaps in the literature included limited sample size and populations, lack of in-depth evaluations, and issues with research design. Although traditionally understudied, there is sufficient evidence to conclude that white matter is critical in the neural control of swallowing. The reviewed studies indicated that white matter damage can be directly tied to swallowing deficits, and several white matter structures were implicated across studies. Further well-designed interdisciplinary research is needed to understand white matter's role in neural control of normal swallowing and in dysphagia recovery and rehabilitation.
PubMed: 34262441
DOI: 10.3389/fnhum.2021.628424 -
Annals of Clinical Psychiatry :... Feb 2020Obsessive-compulsive disorder (OCD) is difficult to treat. Studies have shown associations of white matter pathology in OCD, as well as various other psychiatric...
BACKGROUND
Obsessive-compulsive disorder (OCD) is difficult to treat. Studies have shown associations of white matter pathology in OCD, as well as various other psychiatric illnesses, using diffusion tensor imaging (DTI). We conducted a systematic review of controlled studies on drugnaïve patients with OCD vs pharmacologically treated patients with OCD to examine whether pharmacotherapy exerts changes on white matter in OCD.
METHODS
A search was conducted to identify controlled trials published from January 2010 to July 2018. All studies used DTI to assess for white matter volume in drug-naïve patients with OCD, pharmacologically treated patients with OCD, and healthy controls.
RESULTS
Three studies met the criteria for inclusion. The findings of one study suggest that selective serotonin reuptake inhibitors do exert some changes on white matter, some of which appear to reverse abnormalities noted in the fronto-striato-thalamo-cortical pathways. In another study, no differences in white matter parameters were found between drug-naïve patients vs healthy controls. In a third study, high fractional anisotropy in the splenium correlated with a greater severity of OCD.
CONCLUSIONS
Our systematic review suggests mixed results regarding whether drug-naïve patients with OCD have a difference in white matter compared with pharmacologically treated patients with OCD, and whether patients with OCD have a difference in white matter compared with healthy controls.
Topics: Diffusion Tensor Imaging; Humans; Obsessive-Compulsive Disorder; White Matter
PubMed: 31990968
DOI: No ID Found -
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 -
Clinical Neurology and Neurosurgery Feb 2021Although the changes of diffusion tensor imaging (DTI) in corpus callosum (CC) in patients with relapsing-remitting multiple sclerosis (RRMS) has been reported, the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Although the changes of diffusion tensor imaging (DTI) in corpus callosum (CC) in patients with relapsing-remitting multiple sclerosis (RRMS) has been reported, the results are controversial. We aimed to determine the damage to the CC in patients with RRMS using DTI.
MATERIAL AND METHODS
A systematic search of English databases (PubMed, Embase, Cochrane Library, and Scopus) was performed. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) values of DTI were compared between RRMS patients and healthy controls (HC) using Stata 12.0.
RESULTS
A total of 461 patients and 365 HC from 15 studies were included. Compared with HC, the FA values of the whole CC (SMD -1.894, P < 0.001), genu (SMD -0.830, P < 0.001) and splenium (SMD -1.431, P < 0.001) of CC were significantly reduced in patients with RRMS. Moreover, the MD values of the whole CC (SMD 1.213, P < 0.001), genu (SMD 0.657, P < 0.001) and splenium (SMD 0.830, P < 0.001) of CC were significantly increased in patients with RRMS. Additionally, the AD values (SMD 0.635, P < 0.001) and RD values (SMD 1.480, P < 0.001) were significantly increased in the whole CC in patients with RRMS. The meta-regression analysis revealed that the male ratio showed a significant effect on the FA reduction in the splenium CC in RRMS patients.
CONCLUSIONS
These results indicated that DTI parameters were potential biomarkers with increased sensitivity for detecting pathological damage in the CC in patients with RRMS.
Topics: Adult; Corpus Callosum; Diffusion Tensor Imaging; Female; Humans; Male; Middle Aged; Multiple Sclerosis, Relapsing-Remitting
PubMed: 33373835
DOI: 10.1016/j.clineuro.2020.106442 -
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 -
The International Journal of... Mar 2020Alzheimer's disease is a progressive, irreversible neurodegenerative disorder associated with brain alterations. Diffusion tensor imaging (DTI) has contributed to...
Alzheimer's disease is a progressive, irreversible neurodegenerative disorder associated with brain alterations. Diffusion tensor imaging (DTI) has contributed to identify degeneration in white matter cortical microstructural that can be considered an early and specific biomarker for Alzheimer's disease. This review aimed to provide a summary of DTI studies on white matter damage in Alzheimer's disease. On PubMed, Web of Science and Scopus databases, we reviewed the studies that used DTI for assessing fractional anisotropy in neurofiber tracts involved in Alzheimer's Disease progression: fornix, the cingulum, uncinate fasciculus, superior and inferior longitudinal fasciculus and corpus callosum. We included nine studies that met search criteria. The results showed decreased fractional anisotropy value in mild cognitive impairment (MCI) patients. White matter diffusivity changes were associated with the progression of Alzheimer's disease. Microstructural alterations of the limbic and cortico-cortical tracts could be potential biomarkers for early diagnosis in preclinical disease phase.
Topics: Alzheimer Disease; Diffusion Tensor Imaging; Disease Progression; Humans; Prodromal Symptoms; White Matter
PubMed: 31549530
DOI: 10.1080/00207454.2019.1667798 -
Journal of Neurotrauma Aug 2020There is growing interest in developing magnetic resonance imaging (MRI) biomarkers of brain connectivity from resting-state functional (rs-fMRI) and diffusion tensor...
There is growing interest in developing magnetic resonance imaging (MRI) biomarkers of brain connectivity from resting-state functional (rs-fMRI) and diffusion tensor imaging (DTI) to aid in the diagnosis and management of patients with mild traumatic brain injury (mTBI). To determine whether early MRI biomarkers of brain connectivity are useful in predicting outcome after mTBI, we conducted a systematic review using the following inclusion criteria: 1) patients aged >16 years with mTBI, 2) MRI performed during the first month post-injury, 3) outcome measure available, 4) control group, and 5) original article published in a peer-reviewed journal. Of the 1351 citations identified, 14 studies met inclusion criteria (5 rs-fMRI and 10 DTI; 680 patients with mTBI vs. 436 controls) including those where MRI was performed from <12 h to 1 month post-injury. The most common clinical outcome measure used in these studies was symptom burden using the Rivermead Post-Concussion Questionnaire. The most frequently studied brain connectivity MRI biomarkers were global functional connectivity, default-mode network, and fractional anisotropy (FA). Despite the scant evidence and considerable methodological heterogeneity observed among studies, we conclude that brain connectivity MRI biomarkers obtained within 1 month of injury may be potentially useful in predicting outcome in mTBI. Further longitudinal studies are needed to evaluate the effect of mTBI on MRI-based brain connectivity biomarkers and examine how incorporation of these tests can inform the clinical care of individual mTBI patients.
Topics: Biomarkers; Brain; Brain Concussion; Diffusion Tensor Imaging; Humans; Magnetic Resonance Imaging; Nerve Net; Predictive Value of Tests; Treatment Outcome
PubMed: 32228145
DOI: 10.1089/neu.2019.6623