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AJNR. American Journal of Neuroradiology Jul 2017Concerns have arisen about the long-term health effects of repeat gadolinium injections in patients with multiple sclerosis and the incomplete characterization of MS... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Concerns have arisen about the long-term health effects of repeat gadolinium injections in patients with multiple sclerosis and the incomplete characterization of MS lesion pathophysiology that results from relying on enhancement characteristics alone.
PURPOSE
Our aim was to perform a systematic review and meta-analysis analyzing whether noncontrast MR imaging biomarkers can distinguish enhancing and nonenhancing brain MS lesions.
DATA SOURCES
Our sources were Ovid MEDLINE, Ovid Embase, and the Cochrane data base from inception to August 2016.
STUDY SELECTION
We included 37 journal articles on 985 patients with MS who had MR imaging in which T1-weighted postcontrast sequences were compared with noncontrast sequences obtained during the same MR imaging examination by using ROI analysis of individual MS lesions.
DATA ANALYSIS
We performed random-effects meta-analyses comparing the standard mean difference of each MR imaging metric taken from enhancing-versus-nonenhancing lesions.
DATA SYNTHESIS
DTI-based fractional anisotropy values are significantly different between enhancing and nonenhancing lesions ( = .02), with enhancing lesions showing decreased fractional anisotropy compared with nonenhancing lesions. Of the other most frequently studied MR imaging biomarkers (mean diffusivity, magnetization transfer ratio, or ADC), none were significantly different ( values of 0.30, 0.47, and 0.19. respectively) between enhancing and nonenhancing lesions. Of the limited studies providing diagnostic accuracy measures, gradient-echo-based quantitative susceptibility mapping had the best performance in discriminating enhancing and nonenhancing MS lesions.
LIMITATIONS
MR imaging techniques and patient characteristics were variable across studies. Most studies did not provide diagnostic accuracy measures. All imaging metrics were not studied in all 37 studies.
CONCLUSIONS
Noncontrast MR imaging techniques, such as DTI-based FA, can assess MS lesion acuity without gadolinium.
Topics: Anisotropy; Brain; Contrast Media; Diffusion Tensor Imaging; Gadolinium; Humans; Magnetic Resonance Imaging; Multiple Sclerosis
PubMed: 28522663
DOI: 10.3174/ajnr.A5209 -
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 Neurotrauma Apr 2019Diffusion tensor imaging is a magnetic resonance imaging technique that is uniquely capable of detecting microstructural tissue damage in mild and moderate traumatic... (Comparative Study)
Comparative Study Meta-Analysis
Comparing Region of Interest versus Voxel-Wise Diffusion Tensor Imaging Analytic Methods in Mild and Moderate Traumatic Brain Injury: A Systematic Review and Meta-Analysis.
Diffusion tensor imaging is a magnetic resonance imaging technique that is uniquely capable of detecting microstructural tissue damage in mild and moderate traumatic brain injuries (TBIs). To date, it remains unknown if two common analytic techniques, region of interest (ROI) versus voxel-wise (VW) analyses, detect injury in similar locations. The purpose of this systematic review and meta-analysis was to directly compare the regions of abnormality elucidated by each method. Twenty-seven ROI and 11 VW studies met our inclusion criteria. Our ROI meta-analysis identified 11 regions, including the splenium of the corpus callosum, where fractional anisotropy (FA) was significantly decreased in TBI patients, compared with controls. Likewise, we identified higher mean diffusivity/apparent diffusivity constant in the genu, body, and splenium of the corpus callosum. Alternatively, our VW analysis identified one region of high FA in the right superior longitudinal fasciculus and seven regions of low FA, with the two largest located in the corpus callosum. High mean diffusivity and high radial diffusivity, both in the right inferior longitudinal fasciculus, also was revealed by our VW analysis. Moreover, we have shown that the magnitude of damage in the corpus callosum revealed by ROI analysis (z = -3.15) is greater than that demonstrated by VW analysis (z = -1.41). Overall, this study indicates that both ROI and VW analytic methods are sensitive to low FA in the corpus callosum; however, the ROI method has more power to detect the full extent of tissue abnormality in the corpus callosum. More research utilizing standardized methods and reporting is essential to fully characterize the extent to which ROI and VW analyses can concordantly detect other locations of pathology in mild and moderate TBI patients.
Topics: Brain Concussion; Brain Injuries, Traumatic; Diffusion Tensor Imaging; Humans; Image Interpretation, Computer-Assisted; Neuroimaging
PubMed: 30375271
DOI: 10.1089/neu.2018.5838 -
Revista Brasileira de Psiquiatria (Sao... Mar 2016To review the available data on diffusion tensor imaging (DTI) of subjects with bipolar disorder (BD), with a particular focus on fractional anisotropy (FA) in white... (Review)
Review
OBJECTIVE
To review the available data on diffusion tensor imaging (DTI) of subjects with bipolar disorder (BD), with a particular focus on fractional anisotropy (FA) in white matter (WM) tracts.
METHODS
The PubMed/MEDLINE database was searched for relevant articles, which were included in a systematic review of the literature. FA reductions and WM abnormalities were divided anatomically into three groups: commissural tracts, association tracts, and projection tracts.
RESULTS
Eighteen studies met the inclusion criteria. The corpus callosum was the main impaired commissural tract as demonstrated by FA reductions. Five studies reported FA reductions in the cingulum. Two studies reported decreased FA in the anterior thalamic radiation, and one in the corticospinal tract. Conversely, three studies found increased FA values in WM tracts involved in BD pathophysiology.
CONCLUSION
Despite considerable heterogeneity, these results indicate a direct link between executive cognitive functioning and abnormal WM microstructural integrity of fronto-limbic tracts in patients with remitted BD, providing further evidence of the neuronal disruption that underlies BD symptomatology.
Topics: Anisotropy; Bipolar Disorder; Diffusion Tensor Imaging; Executive Function; Humans; Neural Pathways; White Matter
PubMed: 27007148
DOI: 10.1590/1516-4446-2015-1793 -
European Journal of Sport Science Jan 2023Hypertrophic cardiomyopathy (HCM) is a common cause of sudden cardiac death in athletes. Cardiac Magnetic Resonance (CMR) imaging is considered an excellent tool to...
Hypertrophic cardiomyopathy (HCM) is a common cause of sudden cardiac death in athletes. Cardiac Magnetic Resonance (CMR) imaging is considered an excellent tool to differentiate between HCM and athlete's heart. The aim of this systematic review was to highlight the novel CMR-derived parameters with significant discriminative capacity between the two conditions. A systematic search in the MEDLINE, EMBASE and Cochrane Reviews databases was performed. Eligible studies were considered the ones comparing novel CMR-derived parameters on athletes and HCM patients. Therefore, studies that only examined Cine-derived volumetric parameters were excluded. Particular attention was given to binary classification results from multi-variate regression models and ROC curve analyses. Bias assessment was performed with the Quality Assessment on Diagnostic Accuracy Studies. Five (5) studies were included in the systematic review, with a total of 284 athletes and 373 HCM patients. Several novel indices displayed discriminatory potential, such as native T1 mapping and T2 values, LV global longitudinal strain, late gadolinium enhancement and whole-LV fractal dimension. Diffusion tensor imaging enabled quantification of the secondary eigenvalue angle and fractional anisotropy in one study, which also proved capable of reliably detecting HCM in a mixed athlete/patient sample. Several novel CMR-derived parameters, most of which are currently under development, show promising results in discerning between athlete's heart and HCM. Prospective studies examining the discriminatory capacity of all promising modalities side-by-side will yield definitive answers on their relative importance; diagnostic models can incorporate the best performing variables for optimal results.
Topics: Humans; Cardiomegaly, Exercise-Induced; Contrast Media; Diffusion Tensor Imaging; Prospective Studies; Gadolinium; Cardiomyopathy, Hypertrophic; Magnetic Resonance Imaging
PubMed: 34720041
DOI: 10.1080/17461391.2021.2001576 -
NeuroImage. Clinical 2018White matter plasticity occurs throughout life due to learning and can be a protective factor against as well as a vulnerability factor for the development of mental... (Meta-Analysis)
Meta-Analysis
White matter plasticity occurs throughout life due to learning and can be a protective factor against as well as a vulnerability factor for the development of mental disorders. In this systematic review we summarize findings on structural white matter changes in children and adults with posttraumatic stress disorder (PTSD) and relate them to theoretical accounts of the pathophysiology of PTSD with a focus on the disturbed processing of contexts and associated problems in emotional and cognitive processing and PTSD symptomatology. We particularly examine studies reporting fractional anisotropy (FA) measured with diffusion tensor imaging (DTI). We further subdivided the studies in adult-onset PTSD with traumatic experience in adulthood, adult-onset PTSD with traumatic experience in childhood and children with PTSD. We included 30 studies comprising almost 1700 participants with 450 adults and 300 children suffering from PTSD. Our systematic review showed that for children with PTSD and adult-onset PTSD with childhood trauma, a decrease in FA in the corpus collosum, most prominently in the anterior and posterior midbody, the isthmus and splenium were reported. For adult-onset PTSD with traumatic experience in adulthood, changes in FA in the anterior and posterior part of the cingulum, the superior longitudinal fasciculus and frontal regions were found. Using GingerAle, we also performed a coordinate-based meta-analysis of 14 studies of adult-onset PTSD with traumatic experience in adulthood and did not find any significant clusters. Our results suggest that changes in white matter microstructure vary depending on traumatic experience and are associated with changes in brain circuits related to the processing of contexts. Finally, we present methodological considerations for future studies.
Topics: Anisotropy; Diffusion Tensor Imaging; Emotions; Humans; Nerve Net; Stress Disorders, Post-Traumatic; White Matter
PubMed: 29984166
DOI: 10.1016/j.nicl.2018.05.013 -
NeuroImage Apr 2021Recent years have seen an increased understanding of the importance of myelination in healthy brain function and neuropsychiatric diseases. Non-invasive microstructural... (Meta-Analysis)
Meta-Analysis
Recent years have seen an increased understanding of the importance of myelination in healthy brain function and neuropsychiatric diseases. Non-invasive microstructural magnetic resonance imaging (MRI) holds the potential to expand and translate these insights to basic and clinical human research, but the sensitivity and specificity of different MR markers to myelination is a subject of debate. To consolidate current knowledge on the topic, we perform a systematic review and meta-analysis of studies that validate microstructural imaging by combining it with myelin histology. We find meta-analytic evidence for correlations between various myelin histology metrics and markers from different MRI modalities, including fractional anisotropy, radial diffusivity, macromolecular pool, magnetization transfer ratio, susceptibility and longitudinal relaxation rate, but not mean diffusivity. Meta-analytic correlation effect sizes range widely, between R = 0.26 and R = 0.82. However, formal comparisons between MRI-based myelin markers are limited by methodological variability, inconsistent reporting and potential for publication bias, thus preventing the establishment of a single most sensitive strategy to measure myelin with MRI. To facilitate further progress, we provide a detailed characterisation of the evaluated studies as an online resource. We also share a set of 12 recommendations for future studies validating putative MR-based myelin markers and deploying them in vivo in humans.
Topics: Brain; Humans; Magnetic Resonance Imaging; Myelin Proteins; Myelin Sheath; Qualitative Research; Reproducibility of Results
PubMed: 33524576
DOI: 10.1016/j.neuroimage.2021.117744 -
Frontiers in Neurology 2020Structural brain white matter (WM) changes such as axonal caliber, density, myelination, and orientation, along with WM-dependent structural connectivity, may be...
Structural brain white matter (WM) changes such as axonal caliber, density, myelination, and orientation, along with WM-dependent structural connectivity, may be impacted early in Parkinson disease (PD). Diffusion magnetic resonance imaging (dMRI) has been used extensively to understand such pathological WM changes, and the focus of this systematic review is to understand both the methods utilized and their corresponding results in the context of early-stage PD. Diffusion tensor imaging (DTI) is the most commonly utilized method to probe WM pathological changes. Previous studies have suggested that DTI metrics are sensitive in capturing early disease-associated WM changes in preclinical symptomatic regions such as olfactory regions and the substantia nigra, which is considered to be a hallmark of PD pathology and progression. Postprocessing analytic approaches include region of interest-based analysis, voxel-based analysis, skeletonized approaches, and connectome analysis, each with unique advantages and challenges. While DTI has been used extensively to study WM disorganization in early-stage PD, it has several limitations, including an inability to resolve multiple fiber orientations within each voxel and sensitivity to partial volume effects. Given the subtle changes associated with early-stage PD, these limitations result in inaccuracies that severely impact the reliability of DTI-based metrics as potential biomarkers. To overcome these limitations, advanced dMRI acquisition and analysis methods have been employed, including diffusion kurtosis imaging and q-space diffeomorphic reconstruction. The combination of improved acquisition and analysis in DTI may yield novel and accurate information related to WM-associated changes in early-stage PD. In the current article, we present a systematic and critical review of dMRI studies in early-stage PD, with a focus on recent advances in DTI methodology. Yielding novel metrics, these advanced methods have been shown to detect diffuse WM changes in early-stage PD. These findings support the notion of early axonal damage in PD and suggest that WM pathology may go unrecognized until symptoms appear. Finally, the advantages and disadvantages of different dMRI techniques, analysis methods, and software employed are discussed in the context of PD-related pathology.
PubMed: 32477235
DOI: 10.3389/fneur.2020.00314 -
Frontiers in Human Neuroscience 2015There is overwhelming evidence that autism spectrum disorder (ASD) is related to altered brain connectivity. While these alterations are starting to be well... (Review)
Review
There is overwhelming evidence that autism spectrum disorder (ASD) is related to altered brain connectivity. While these alterations are starting to be well characterized in subjects where the clinical picture is fully expressed, less is known on their earlier developmental course. In the present study we systematically reviewed current knowledge on structural connectivity in ASD infants and toddlers. We searched PubMed and Medline databases for all English language papers, published from year 2000, exploring structural connectivity in populations of infants and toddlers whose mean age was below 30 months. Of the 264 papers extracted, four were found to be eligible and were reviewed. Three of the four selected studies reported higher fractional anisotropy values in subjects with ASD compared to controls within commissural fibers, projections fibers, and association fibers, suggesting brain hyper-connectivity in the earliest phases of the disorder. Similar conclusions emerged from the other diffusion parameters assessed. These findings are reversed to what is generally found in studies exploring older patient groups and suggest a developmental course characterized by a shift toward hypo-connectivity starting at a time between two and four years of age.
PubMed: 25859207
DOI: 10.3389/fnhum.2015.00159 -
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