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Brain Communications 2022Myelin-sensitive MRI such as magnetization transfer imaging has been widely used in multiple sclerosis. The influence of methodology and differences in disease subtype... (Review)
Review
Myelin-sensitive MRI such as magnetization transfer imaging has been widely used in multiple sclerosis. The influence of methodology and differences in disease subtype on imaging findings is, however, not well established. Here, we systematically review magnetization transfer brain imaging findings in relapsing-remitting multiple sclerosis. We examine how methodological differences, disease effects and their interaction influence magnetization transfer imaging measures. Articles published before 06/01/2021 were retrieved from online databases (PubMed, EMBASE and Web of Science) with search terms including 'magnetization transfer' and 'brain' for systematic review, according to a pre-defined protocol. Only studies that used human quantitative magnetization transfer imaging in adults with relapsing-remitting multiple sclerosis (with or without healthy controls) were included. Additional data from relapsing-remitting multiple sclerosis subjects acquired in other studies comprising mixed disease subtypes were included in meta-analyses. Data including sample size, MRI acquisition protocol parameters, treatments and clinical findings were extracted and qualitatively synthesized. Where possible, effect sizes were calculated for meta-analyses to determine magnetization transfer (i) differences between patients and healthy controls; (ii) longitudinal change and (iii) relationships with clinical disability in relapsing-remitting multiple sclerosis. Eighty-six studies met inclusion criteria. MRI acquisition parameters varied widely, and were also underreported. The majority of studies examined the magnetization transfer ratio in white matter, but magnetization transfer metrics, brain regions examined and results were heterogeneous. The analysis demonstrated a risk of bias due to selective reporting and small sample sizes. The pooled random-effects meta-analysis across all brain compartments revealed magnetization transfer ratio was 1.17 per cent units (95% CI -1.42 to -0.91) lower in relapsing-remitting multiple sclerosis than healthy controls (-value: -8.99, < 0.001, 46 studies). Linear mixed-model analysis did not show a significant longitudinal change in magnetization transfer ratio across all brain regions [ = 0.12 (-0.56 to 0.80), -value = 0.35, = 0.724, 14 studies] or normal-appearing white matter alone [ = 0.037 (-0.14 to 0.22), -value = 0.41, = 0.68, eight studies]. There was a significant negative association between the magnetization transfer ratio and clinical disability, as assessed by the Expanded Disability Status Scale [ = -0.32 (95% CI -0.46 to -0.17); -value = -4.33, < 0.001, 13 studies]. Evidence suggests that magnetization transfer imaging metrics are sensitive to pathological brain changes in relapsing-remitting multiple sclerosis, although effect sizes were small in comparison to inter-study variability. Recommendations include: better harmonized magnetization transfer acquisition protocols with detailed methodological reporting standards; larger, well-phenotyped cohorts, including healthy controls; and, further exploration of techniques such as magnetization transfer saturation or inhomogeneous magnetization transfer ratio.
PubMed: 35652121
DOI: 10.1093/braincomms/fcac088 -
A systematic review of the association between dementia risk factors and cerebrovascular reactivity.Neuroscience and Biobehavioral Reviews May 2023Cumulative evidence suggests that impaired cerebrovascular reactivity (CVR), a regulatory response critical for maintaining neuronal health, is amongst the earliest... (Review)
Review
Cumulative evidence suggests that impaired cerebrovascular reactivity (CVR), a regulatory response critical for maintaining neuronal health, is amongst the earliest pathological changes in dementia. However, we know little about how CVR is affected by dementia risk, prior to disease onset. Understanding this relationship would improve our knowledge of disease pathways and help inform preventative interventions. This systematic review investigates 59 studies examining how CVR (measured by magnetic resonance imaging) is affected by modifiable, non-modifiable, and clinical risk factors for dementia. We report that non-modifiable risk (older age and apolipoprotein ε4), some modifiable factors (diabetes, traumatic brain injury, hypertension) and some clinical factors (stroke, carotid artery occlusion, stenosis) were consistently associated with reduced CVR. We also note a lack of conclusive evidence on how other behavioural factors such as physical inactivity, obesity, or depression, affect CVR. This review explores the biological mechanisms underpinning these brain-behaviour associations, highlights evident gaps in the literature, and identifies the risk factors that could be managed to preserve CVR in an effort to prevent dementia.
Topics: Humans; Brain; Stroke; Risk Factors; Magnetic Resonance Imaging; Dementia; Cerebrovascular Circulation
PubMed: 36944391
DOI: 10.1016/j.neubiorev.2023.105140 -
Neuropharmacology Feb 2023The microbiota-gut-brain axis (MGBA) refers to the bidirectional communication between the brain and the gut microbiota and recent studies have linked the MGBA to health... (Review)
Review
The microbiota-gut-brain axis (MGBA) refers to the bidirectional communication between the brain and the gut microbiota and recent studies have linked the MGBA to health and disease. Research has so far investigated this axis mainly from microbiota to brain but less is known about the other direction. One approach to examine the MGBA from brain to microbiota is through understanding if and how neuromodulation might impact microbiota. Neuromodulation encompasses a wide range of stimulation techniques and is used to treat neurological, psychiatric and metabolic disorders, like Parkinson's Disease, depression and obesity. Here, we performed a systematic review to investigate whether neuromodulation is associated with subsequent changes in the gut microbiota. Searches in PsycINFO and MEDLINE were performed up to March 2022. Included studies needed to be clinical or preclinical studies comparing the effects of deep brain stimulation, electroconvulsive therapy, repetitive transcranial magnetic stimulation, transcranial direct current stimulation or vagal nerve stimulation on the gut microbiota before and after treatment or between active and control groups. Seven studies were identified. Neuromodulation was associated with changes in relative bacterial abundances, but not with (changes in) α-diversity or β-diversity. Summarizing, currently reported findings suggest that neuromodulation interventions are associated with moderate changes in the gut microbiome. However, findings remain inconclusive due to the limited number and varying quality of included studies, as well as the large heterogeneity between studies. More research is required to more conclusively establish whether, and if so, via which mechanism(s) of action neuromodulation interventions might influence the gut microbiota.
Topics: Transcranial Direct Current Stimulation; Transcranial Magnetic Stimulation; Vagus Nerve Stimulation; Deep Brain Stimulation; Brain
PubMed: 36334762
DOI: 10.1016/j.neuropharm.2022.109318 -
Journal of Affective Disorders Nov 2020Major Depressive Disorder (MDD) is a global disorder that negatively affects mood and quality of life. Antidepressant medication and psychotherapy are the most commonly... (Review)
Review
BACKGROUND
Major Depressive Disorder (MDD) is a global disorder that negatively affects mood and quality of life. Antidepressant medication and psychotherapy are the most commonly prescribed treatments, but prior research has called their clinical efficacy into question. These treatments may be less effective when the patient has a diagnosed comorbid disorder.
METHOD
A systematic review of the literature was conducted to investigate whether an alternative method of treatment, Transcranial Magnetic Stimulation (TMS), is effective for MDD with a diagnosed comorbidity. 110 articles were identified, of which 8 were included in the current review.
RESULTS
Response and remission rates vary. A range of 39.5-70% of participants experienced an antidepressant response to treatment, and 16.6-76.9% of patients achieved remission from MDD. A range of 48.6-84.6% of participants responded to treatment of their comorbid disorder, and 50-84.6% achieved remission of comorbid symptoms.
LIMITATIONS
Limitations of the current review include small sample sizes, limited statistical power, homogenous samples, and a lack of sham or placebo-controlled studies.
CONCLUSION
Preliminary results support that TMS is effective at treating symptoms of MDD and a comorbid disorder. Additional studies are needed to confirm these results.
Topics: Antidepressive Agents; Depression; Depressive Disorder, Major; Humans; Quality of Life; Transcranial Magnetic Stimulation; Treatment Outcome
PubMed: 32871677
DOI: 10.1016/j.jad.2020.07.025 -
Journal of Magnetic Resonance Imaging :... Jun 2021Clinical examination and lymphoscintigraphy are the current standard for investigating lymphatic function. Magnetic resonance imaging (MRI) facilitates three-dimensional...
BACKGROUND
Clinical examination and lymphoscintigraphy are the current standard for investigating lymphatic function. Magnetic resonance imaging (MRI) facilitates three-dimensional (3D), nonionizing imaging of the lymphatic vasculature, including functional assessments of lymphatic flow, and may improve diagnosis and treatment planning in disease states such as lymphedema.
PURPOSE
To summarize the role of MRI as a noninvasive technique to assess lymphatic drainage and highlight areas in need of further study.
STUDY TYPE
Systematic review.
POPULATION
In October 2019, a systematic literature search (PubMed) was performed to identify articles on magnetic resonance lymphangiography (MRL).
FIELD STRENGTH/SEQUENCE
No field strength or sequence restrictions.
ASSESSMENT
Article quality assessment was conducted using a bespoke protocol, designed with heavy reliance on the National Institutes of Health quality assessment tool for case series studies and Downs and Blacks quality checklist for health care intervention studies.
STATISTICAL TESTS
The results of the original research articles are summarized.
RESULTS
From 612 identified articles, 43 articles were included and their protocols and results summarized. Field strength was 1.5 or 3.0 T in all studies, with 25/43 (58%) employing 3.0 T imaging. Most commonly, imaging of the peripheries, upper and lower limbs including the pelvis (32/43, 74%), and the trunk (10/43, 23%) is performed, including two studies covering both regions. Imaging protocols were heterogenous; however, T -weighted and contrast-enhanced T -weighted images are routinely acquired and demonstrate the lymphatic vasculature. Edema, vessel, quantity and morphology, and contrast uptake characteristics are commonly reported indicators of lymphatic dysfunction.
DATA CONCLUSION
MRL is uniquely placed to yield large field of view, qualitative and quantitative, 3D imaging of the lymphatic vasculature. Despite study heterogeneity, consensus is emerging regarding MRL protocol design. MRL has the potential to dramatically improve understanding of the lymphatics and detect disease, but further optimization, and research into the influence of study protocol differences, is required before this is fully realized.
LEVEL OF EVIDENCE
2 TECHNICAL EFFICACY: Stage 2.
Topics: Contrast Media; Humans; Lymphatic Vessels; Lymphedema; Lymphography; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy
PubMed: 33625795
DOI: 10.1002/jmri.27542 -
Chronic Stress (Thousand Oaks, Calif.) 2022A stressor-related disorder wherein traumatic experience precipitates protracted disruptions to mood and cognition, post-traumatic stress disorder (PTSD) is associated... (Review)
Review
A stressor-related disorder wherein traumatic experience precipitates protracted disruptions to mood and cognition, post-traumatic stress disorder (PTSD) is associated with wide-ranging abnormalities across the body. While various methods have investigated these deviations, only proton magnetic resonance spectroscopy (H MRS) enables noninvasive measurement of small-molecule metabolites in the living human. H MRS has correspondingly been employed to test hypotheses about the composition and function of multiple brain regions putatively involved in PTSD. Here we systematically review methodological considerations and reported findings, both positive and negative, of the current H-MRS literature in PTSD (N = 32 studies) to communicate the brain regional metabolite alterations heretofore observed, providing random-effects model meta-analyses for those most extensively studied. Our review suggests significant PTSD-associated decreases in N-acetyl aspartate in bilateral hippocampus and anterior cingulate cortex with less evident effect in other metabolites and regions. Model heterogeneities diverged widely by analysis (I < 0.01% to 90.1%) and suggested regional dependence on quantification reference (creatine or otherwise). While observed variabilities in methods and reported findings suggest that H-MRS explorations of PTSD could benefit from methodological standardization, informing this standardization by quantitative assessment of the existing literature is currently hampered by its small size and limited scope.
PubMed: 36237981
DOI: 10.1177/24705470221128004 -
European Radiology Jul 2024Cytotoxic lesions of the corpus callosum (CLOCC) are a common magnetic resonance imaging (MRI) finding associated with various systemic diseases including COVID-19.... (Review)
Review
OBJECTIVES
Cytotoxic lesions of the corpus callosum (CLOCC) are a common magnetic resonance imaging (MRI) finding associated with various systemic diseases including COVID-19. Although an increasing number of such cases is reported in the literature, there is a lack of systematic evidence summarizing the etiology and neuroimaging findings of these lesions. Thus, the aim of this systematic review was to synthesize the applied nomenclature, neuroimaging and clinical features, and differential diagnoses as well as associated disease entities of CLOCC.
MATERIALS AND METHODS
A comprehensive literature search in three biomedical databases identified 441 references, out of which 324 were eligible for a narrative summary including a total of 1353 patients.
RESULTS
Our PRISMA-conform systematic review identifies a broad panel of disease entities which are associated with CLOCC, among them toxic/drug-treatment-associated, infectious (viral, bacterial), vascular, metabolic, traumatic, and neoplastic entities in both adult and pediatric individuals. On MRI, CLOCC show typical high T2 signal, low T1 signal, restricted diffusion, and lack of contrast enhancement. The majority of the lesions were reversible within the follow-up period (median follow-up 3 weeks). Interestingly, even though CLOCC were mostly associated with symptoms of the underlying disease, in exceptional cases, CLOCC were associated with callosal neurological symptoms. Of note, employed nomenclature for CLOCC was highly inconsistent.
CONCLUSIONS
Our study provides high-level evidence for clinical and imaging features of CLOCC as well as associated disease entities.
CLINICAL RELEVANCE STATEMENT
Our study provides high-level evidence on MRI features of CLOCC as well as a comprehensive list of disease entities potentially associated with CLOCC. Together, this will facilitate rigorous diagnostic workup of suspected CLOCC cases.
KEY POINTS
• Cytotoxic lesions of the corpus callosum (CLOCC) are a frequent MRI feature associated with various systemic diseases. • Cytotoxic lesions of the corpus callosum show a highly homogenous MRI presentation and temporal dynamics. • This comprehensive overview will benefit (neuro)radiologists during diagnostic workup.
Topics: Humans; Corpus Callosum; Magnetic Resonance Imaging; COVID-19; Brain Diseases; Neuroimaging; Diagnosis, Differential
PubMed: 38147170
DOI: 10.1007/s00330-023-10524-3 -
Cognitive, Affective & Behavioral... Feb 2024All experiences preserved within episodic memory contain information on the space and time of events. The hippocampus is the main brain region involved in processing... (Meta-Analysis)
Meta-Analysis Review
All experiences preserved within episodic memory contain information on the space and time of events. The hippocampus is the main brain region involved in processing spatial and temporal information for incorporation within episodic memory representations. However, the other brain regions involved in the encoding and retrieval of spatial and temporal information within episodic memory are unclear, because a systematic review of related studies is lacking and the findings are scattered. The present study was designed to integrate the results of functional magnetic resonance imaging and positron emission tomography studies by means of a systematic review and meta-analysis to provide converging evidence. In particular, we focused on identifying the brain regions involved in the retrieval of spatial and temporal information. We identified a spatial retrieval network consisting of the inferior temporal gyrus, parahippocampal gyrus, superior parietal lobule, angular gyrus, and precuneus. Temporal context retrieval was supported by the dorsolateral prefrontal cortex. Thus, the retrieval of spatial and temporal information is supported by different brain regions, highlighting their different natures within episodic memory.
Topics: Humans; Memory, Episodic; Brain Mapping; Brain; Temporal Lobe; Parietal Lobe; Magnetic Resonance Imaging; Mental Recall
PubMed: 38030912
DOI: 10.3758/s13415-023-01140-1 -
Clinical Rheumatology Sep 2023C-reactive protein (CRP) and magnetic resonance imaging (MRI) are widely used to monitor inflammation in patients with axial spondyloarthritis (axSpA), but the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
C-reactive protein (CRP) and magnetic resonance imaging (MRI) are widely used to monitor inflammation in patients with axial spondyloarthritis (axSpA), but the relationship between CRP and MRI-detected inflammation is incompletely understood. The present study was undertaken to assess correlations between CRP and MRI-detected inflammation in axSpA.
MATERIALS AND METHODS
A systematic literature search was performed (Medline, Embase, and Cochrane Library) to identify relevant studies concerning CRP and MRI-detected inflammation in axSpA patients. The MRI-detected inflammation was evaluated by MRI-based disease activity score (DAS). The correlation between CRP and MRI-based DAS was integrated by random-effect models.
RESULTS
Eighteen studies reported a total of 1392 axSpA patients which were included in this meta-analysis. CRP was significantly associated with spinal MR DAS (r=0.226, 95%CI [0.149, 0.291], p<0.001, I=23%). We also found a moderate correlation between CRP change and spinal MR DAS change (r[ASspiMRI-a]=0.354, 95%CI [0.282, 0.422], p<0.001, I=48%; r[SPARCC]=0.544, 95%CI [0.345, 0.701], p<0.001, I=19%). CRP at baseline was negatively associated with improvement in spinal MR DAS (r= - 0.327, 95%CI [-0.397, -0.264], p<0.001, I=0%). However, no significant association was found between CRP and sacroiliac joint (SIJ) MR DAS.
CONCLUSIONS
In axSpA patients, CRP is associated with MRI-detected inflammation in the spine but not in SIJ. We speculate that CRP could be a reasonable index to reflect spinal inflammation. Therefore, we suggest it is not essential to repeat spinal MRI in a short term, while SIJ MRI may be necessary to provide additional information on inflammation. Key Points • CRP is associated with MRI-detected inflammation in the spine but not in sacroiliac joints. • CRP at baseline was negatively associated with improvement in spinal MR DAS. • It was not essential to repeat spinal MRI frequently, while SIJ MRI may be necessary to provide additional information on inflammation.
Topics: Humans; C-Reactive Protein; Spondylarthritis; Inflammation; Sacroiliac Joint; Magnetic Resonance Imaging; Axial Spondyloarthritis
PubMed: 37336841
DOI: 10.1007/s10067-023-06658-w -
International Journal of Environmental... Apr 2022To assess the event rates of myocarditis detected by Cardiac Magnetic Resonance (CMR) in athletes who recovered from COVID-19. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
To assess the event rates of myocarditis detected by Cardiac Magnetic Resonance (CMR) in athletes who recovered from COVID-19.
METHODS
A systematic literature search was performed to identify studies reporting abnormal CMR findings in athletes who recovered from COVID-19. Secondary analyses were performed considering increased serum high sensitivity troponin (hs-Tn) levels and electrocardiographic (ECG) and echocardiographic (ECHO) abnormalities.
RESULTS
In total, 7988 athletes from 15 studies were included in the analysis. The pooled event rate of myocarditis was 1% (CI 1-2%), reaching 4% in the sub-group analysis. In addition, heterogeneity was observed (I2 43.8%). The pooled event rates of elevated serum hs-Tn levels, abnormal ECG and ECHO findings were 2% (CI 1-5%), 3% (CI 1-10%) and 2% (CI 1-6%), respectively. ECG, ECHO and serum hs-Tn level abnormalities did not show any correlation with myocarditis.
CONCLUSIONS
The prevalence of COVID-19-related myocarditis in the athletic population ranges from 1 to 4%. Even if the event rate is quite low, current screening protocols are helpful tools for a safe return to play to properly address CMR studies.
TRIAL REGISTRATION
the study protocol was registered in the PROSPERO database (registration number: CRD42022300819).
Topics: Athletes; COVID-19; Humans; Magnetic Resonance Imaging; Myocarditis; SARS-CoV-2
PubMed: 35409960
DOI: 10.3390/ijerph19074279