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Human Brain Mapping Jun 2021Resting-state fMRI (rs-fMRI) detects functional connectivity (FC) abnormalities that occur in the brains of patients with Alzheimer's disease (AD) and mild cognitive...
Resting-state fMRI (rs-fMRI) detects functional connectivity (FC) abnormalities that occur in the brains of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). FC of the default mode network (DMN) is commonly impaired in AD and MCI. We conducted a systematic review aimed at determining the diagnostic power of rs-fMRI to identify FC abnormalities in the DMN of patients with AD or MCI compared with healthy controls (HCs) using machine learning (ML) methods. Multimodal support vector machine (SVM) algorithm was the commonest form of ML method utilized. Multiple kernel approach can be utilized to aid in the classification by incorporating various discriminating features, such as FC graphs based on "nodes" and "edges" together with structural MRI-based regional cortical thickness and gray matter volume. Other multimodal features include neuropsychiatric testing scores, DTI features, and regional cerebral blood flow. Among AD patients, the posterior cingulate cortex (PCC)/Precuneus was noted to be a highly affected hub of the DMN that demonstrated overall reduced FC. Whereas reduced DMN FC between the PCC and anterior cingulate cortex (ACC) was observed in MCI patients. Evidence indicates that the nodes of the DMN can offer moderate to high diagnostic power to distinguish AD and MCI patients. Nevertheless, various concerns over the homogeneity of data based on patient selection, scanner effects, and the variable usage of classifiers and algorithms pose a challenge for ML-based image interpretation of rs-fMRI datasets to become a mainstream option for diagnosing AD and predicting the conversion of HC/MCI to AD.
Topics: Alzheimer Disease; Cognitive Dysfunction; Connectome; Humans; Machine Learning; Magnetic Resonance Imaging; Predictive Value of Tests
PubMed: 33942449
DOI: 10.1002/hbm.25369 -
European Heart Journal Sep 2018To determine the ranges of pre-test probability (PTP) of coronary artery disease (CAD) in which stress electrocardiogram (ECG), stress echocardiography, coronary... (Meta-Analysis)
Meta-Analysis
The performance of non-invasive tests to rule-in and rule-out significant coronary artery stenosis in patients with stable angina: a meta-analysis focused on post-test disease probability.
AIMS
To determine the ranges of pre-test probability (PTP) of coronary artery disease (CAD) in which stress electrocardiogram (ECG), stress echocardiography, coronary computed tomography angiography (CCTA), single-photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance (CMR) can reclassify patients into a post-test probability that defines (>85%) or excludes (<15%) anatomically (defined by visual evaluation of invasive coronary angiography [ICA]) and functionally (defined by a fractional flow reserve [FFR] ≤0.8) significant CAD.
METHODS AND RESULTS
A broad search in electronic databases until August 2017 was performed. Studies on the aforementioned techniques in >100 patients with stable CAD that utilized either ICA or ICA with FFR measurement as reference, were included. Study-level data was pooled using a hierarchical bivariate random-effects model and likelihood ratios were obtained for each technique. The PTP ranges for each technique to rule-in or rule-out significant CAD were defined. A total of 28 664 patients from 132 studies that used ICA as reference and 4131 from 23 studies using FFR, were analysed. Stress ECG can rule-in and rule-out anatomically significant CAD only when PTP is ≥80% (76-83) and ≤19% (15-25), respectively. Coronary computed tomography angiography is able to rule-in anatomic CAD at a PTP ≥58% (45-70) and rule-out at a PTP ≤80% (65-94). The corresponding PTP values for functionally significant CAD were ≥75% (67-83) and ≤57% (40-72) for CCTA, and ≥71% (59-81) and ≤27 (24-31) for ICA, demonstrating poorer performance of anatomic imaging against FFR. In contrast, functional imaging techniques (PET, stress CMR, and SPECT) are able to rule-in functionally significant CAD when PTP is ≥46-59% and rule-out when PTP is ≤34-57%.
CONCLUSION
The various diagnostic modalities have different optimal performance ranges for the detection of anatomically and functionally significant CAD. Stress ECG appears to have very limited diagnostic power. The selection of a diagnostic technique for any given patient to rule-in or rule-out CAD should be based on the optimal PTP range for each test and on the assumed reference standard.
Topics: Angina, Stable; Computed Tomography Angiography; Coronary Angiography; Coronary Stenosis; Echocardiography, Stress; Electrocardiography; Humans; Magnetic Resonance Angiography; Positron-Emission Tomography; Probability; Single Photon Emission Computed Tomography Computed Tomography
PubMed: 29850808
DOI: 10.1093/eurheartj/ehy267 -
European Annals of Otorhinolaryngology,... Sep 2017To review the optimal techniques for localization and characterization of neck paragangliomas (PGL). (Review)
Review
OBJECTIVE
To review the optimal techniques for localization and characterization of neck paragangliomas (PGL).
MATERIAL AND METHODS
Systematic review of the literature from the PubMed/Medline database.
RESULTS
Neck PGL are hypervascular tumours essentially arising from paraganglionic tissue situated at the carotid bifurcation (carotid body) and along the vagus nerve. Morphological and functional imaging are indicated to confirm the diagnosis, identify multifocal disease and for local and regional staging. MR angiography is the noninvasive technique of choice. CT scan and especially CT angiography are excellent alternatives for diagnosis and staging. Conventional arteriography remains useful preoperatively for embolization and occlusion tests. Functional imaging allows localization and characterization of PGLs. Somatostatin receptor scintigraphy (SRS) was the reference imaging technique for staging of sporadic PGLs. The indications for PET imaging have been extended over recent years in parallel with the development of new tracers such as [F]-FDOPA PET or Gallium-labelled DOTA peptides. Gallium-labelled DOTA peptides has become the first-line imaging modality in the evaluation of cervical PGLs, regardless of the genetic background.
CONCLUSION
Morphological and functional imaging is essential for the staging of neck PGL.
Topics: Computed Tomography Angiography; Head and Neck Neoplasms; Humans; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Neoplasm Staging; Paraganglioma; Positron-Emission Tomography; Predictive Value of Tests; Radiopharmaceuticals; Sensitivity and Specificity; Tomography, X-Ray Computed
PubMed: 27887852
DOI: 10.1016/j.anorl.2016.10.003 -
Theranostics 2023Recent studies suggest that Ga-FAPI PET/CT demonstrated superiority over F-FDG PET/CT in the evaluation of various cancer types, especially in gastric cancer (GC). By... (Meta-Analysis)
Meta-Analysis
Recent studies suggest that Ga-FAPI PET/CT demonstrated superiority over F-FDG PET/CT in the evaluation of various cancer types, especially in gastric cancer (GC). By comprehensively reviewing and analysing the differences between Ga-FAPI and F-FDG in GC, some evidence is provided to foster the broader clinical application of FAPI PET imaging. In this review, studies published up to July 3, 2023, that employed radionuclide labelled FAPI as a diagnostic radiotracer for PET in GC were analysed. These studies were sourced from both the PubMed and Web of Science databases. Our statistical analysis involved a bivariate meta-analysis of the diagnostic data and a meta-analysis of the quantitative metrics. These were performed using R language. The meta-analysis included 14 studies, with 527 patients, of which 358 were diagnosed with GC. Overall, Ga-FAPI showed higher pooled sensitivity (0.84 [95% CI 0.67-0.94] 0.46 [95% CI 0.32-0.60]), specificity (0.91 [95% CI 0.76-0.98] 0.88 [95% CI 0.74-0.96]) and area under the curve (AUC) (0.92 [95% CI 0.77-0.98] 0.52 [95% CI 0.38-0.86]) than F-FDG. The evidence showed superior pooled sensitivities of Ga-FAPI PET over F-FDG for primary tumours, local recurrence, lymph node metastases, distant metastases, and peritoneal metastases. Furthermore, Ga-FAPI PET provided higher maximum standardized uptake value (SUVmax) and tumour-to-background ratios (TBR). For bone metastases, while Ga-FAPI PET demonstrated slightly lower patient-based pooled sensitivity (0.93 1.00), it significantly outperformed F-FDG in the lesion-based analysis (0.95 0.65). However, SUVmax (mean difference [MD] 1.79 [95% CI -3.87-7.45]) and TBR (MD 5.01 [95% CI -0.78-10.80]) of bone metastases showed no significant difference between Ga-FAPI PET/CT and F-FDG PET/CT. Compared with F-FDG, Ga-FAPI PET imaging showed improved diagnostic accuracy in the evaluation of GC. It can be effectively applied to the early diagnosis, initial staging, and detection of recurrence/metastases of GC. Ga-FAPI may have the potential of replacing F-FDG in GC in future applications.
Topics: Humans; Stomach Neoplasms; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18; Gallium Radioisotopes; Positron-Emission Tomography
PubMed: 37649615
DOI: 10.7150/thno.88335 -
Neuroscience and Biobehavioral Reviews Jan 2023Glutamatergic and GABAergic dysfunction are implicated in the pathophysiology of schizophrenia. Previous work has shown relationships between glutamate, GABA, and brain... (Review)
Review
Glutamatergic and GABAergic dysfunction are implicated in the pathophysiology of schizophrenia. Previous work has shown relationships between glutamate, GABA, and brain activity in healthy volunteers. We conducted a systematic review to evaluate whether these relationships are disrupted in psychosis. Primary outcomes were the relationship between metabolite levels and fMRI BOLD response in psychosis relative to healthy volunteers. 17 case-control studies met inclusion criteria (594 patients and 538 healthy volunteers). Replicated findings included that in psychosis, positive associations between ACC glutamate levels and brain activity are reduced during resting state conditions and increased during cognitive control tasks, and negative relationships between GABA and local activation in the ACC are reduced. There was evidence that antipsychotic medication may alter the relationship between glutamate levels and brain activity. Emerging literature is providing insights into disrupted relationships between neurometabolites and brain activity in psychosis. Future studies determining a link to clinical variables may develop this approach for biomarker applications, including development or targeting novel therapeutics.
Topics: Humans; Glutamic Acid; Psychotic Disorders; Schizophrenia; Magnetic Resonance Imaging; gamma-Aminobutyric Acid
PubMed: 36549375
DOI: 10.1016/j.neubiorev.2022.105010 -
Molecular Psychiatry Aug 2023Psychotic disorders are characterized by structural and functional abnormalities in brain networks. Neuroimaging techniques map and characterize such abnormalities using... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Psychotic disorders are characterized by structural and functional abnormalities in brain networks. Neuroimaging techniques map and characterize such abnormalities using unique features (e.g., structural integrity, coactivation). However, it is unclear if a specific method, or a combination of modalities, is particularly effective in identifying differences in brain networks of someone with a psychotic disorder.
METHODS
A systematic meta-analysis evaluated machine learning classification of schizophrenia spectrum disorders in comparison to healthy control participants using various neuroimaging modalities (i.e., T1-weighted imaging (T1), diffusion tensor imaging (DTI), resting state functional connectivity (rs-FC), or some combination (multimodal)). Criteria for manuscript inclusion included whole-brain analyses and cross-validation to provide a complete picture regarding the predictive ability of large-scale brain systems in psychosis. For this meta-analysis, we searched Ovid MEDLINE, PubMed, PsychInfo, Google Scholar, and Web of Science published between inception and March 13th 2023. Prediction results were averaged for studies using the same dataset, but parallel analyses were run that included studies with pooled sample across many datasets. We assessed bias through funnel plot asymmetry. A bivariate regression model determined whether differences in imaging modality, demographics, and preprocessing methods moderated classification. Separate models were run for studies with internal prediction (via cross-validation) and external prediction.
RESULTS
93 studies were identified for quantitative review (30 T1, 9 DTI, 40 rs-FC, and 14 multimodal). As a whole, all modalities reliably differentiated those with schizophrenia spectrum disorders from controls (OR = 2.64 (95%CI = 2.33 to 2.95)). However, classification was relatively similar across modalities: no differences were seen across modalities in the classification of independent internal data, and a small advantage was seen for rs-FC studies relative to T1 studies in classification in external datasets. We found large amounts of heterogeneity across results resulting in significant signs of bias in funnel plots and Egger's tests. Results remained similar, however, when studies were restricted to those with less heterogeneity, with continued small advantages for rs-FC relative to structural measures. Notably, in all cases, no significant differences were seen between multimodal and unimodal approaches, with rs-FC and unimodal studies reporting largely overlapping classification performance. Differences in demographics and analysis or denoising were not associated with changes in classification scores.
CONCLUSIONS
The results of this study suggest that neuroimaging approaches have promise in the classification of psychosis. Interestingly, at present most modalities perform similarly in the classification of psychosis, with slight advantages for rs-FC relative to structural modalities in some specific cases. Notably, results differed substantially across studies, with suggestions of biased effect sizes, particularly highlighting the need for more studies using external prediction and large sample sizes. Adopting more rigorous and systematized standards will add significant value toward understanding and treating this critical population.
Topics: Humans; Diffusion Tensor Imaging; Neuroimaging; Psychotic Disorders; Brain; Schizophrenia; Magnetic Resonance Imaging
PubMed: 37563277
DOI: 10.1038/s41380-023-02195-9 -
Molecular Autism Apr 2024This meta-analysis aimed to explore the most robust findings across numerous existing resting-state functional imaging and voxel-based morphometry (VBM) studies on the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
This meta-analysis aimed to explore the most robust findings across numerous existing resting-state functional imaging and voxel-based morphometry (VBM) studies on the functional and structural brain alterations in individuals with autism spectrum disorder (ASD).
METHODS
A whole-brain voxel-wise meta-analysis was conducted to compare the differences in the intrinsic functional activity and gray matter volume (GMV) between individuals with ASD and typically developing individuals (TDs) using Seed-based d Mapping software.
RESULTS
A total of 23 functional imaging studies (786 ASD, 710 TDs) and 52 VBM studies (1728 ASD, 1747 TDs) were included. Compared with TDs, individuals with ASD displayed resting-state functional decreases in the left insula (extending to left superior temporal gyrus [STG]), bilateral anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC), left angular gyrus and right inferior temporal gyrus, as well as increases in the right supplementary motor area and precuneus. For VBM meta-analysis, individuals with ASD displayed decreased GMV in the ACC/mPFC and left cerebellum, and increased GMV in the left middle temporal gyrus (extending to the left insula and STG), bilateral olfactory cortex, and right precentral gyrus. Further, individuals with ASD displayed decreased resting-state functional activity and increased GMV in the left insula after overlapping the functional and structural differences.
CONCLUSIONS
The present multimodal meta-analysis demonstrated that ASD exhibited similar alterations in both function and structure of the insula and ACC/mPFC, and functional or structural alterations in the default mode network (DMN), primary motor and sensory regions. These findings contribute to further understanding of the pathophysiology of ASD.
Topics: Humans; Autism Spectrum Disorder; Brain; Cerebral Cortex; Gray Matter; Gyrus Cinguli; Magnetic Resonance Imaging
PubMed: 38576034
DOI: 10.1186/s13229-024-00593-6 -
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 -
Journal of Clinical Medicine Oct 2021Due to their non-specific diagnostic patterns of ocular infection, differential diagnosis between () and can be challenging. In both disorders, ocular manifestation... (Review)
Review
Due to their non-specific diagnostic patterns of ocular infection, differential diagnosis between () and can be challenging. In both disorders, ocular manifestation can be the first sign of a systemic infection, and a delayed diagnosis might reduce the response to treatment leading to negative outcomes. Thus, it becomes imperative to distinguish chorioretinal lesions associated with , from lesions due to and other infectious disorders. To date, multimodal non-invasive imaging modalities that include ultra-wide field fundus photography, fluorescein and indocyanine green angiography, optical coherence tomography and optical coherence tomography angiography, facilitate in vivo examination of retinal and choroidal tissues, enabling early diagnosis, monitoring treatment response, and relapse detection. This approach is crucial to differentiate between active and inactive ocular disease, and guides clinicians in their decisional-tree during the patients' follow-up. In this review, we summarized and compared the available literature on multimodal imaging data of infection and tuberculosis, emphasizing similarities and differences in imaging patterns between these two entities and highlighting the relevance of multimodal imaging in the management of the infections.
PubMed: 34768406
DOI: 10.3390/jcm10214880 -
Frontiers in Neuroendocrinology Jan 2021Increasing evidence indicates that ovarian hormones affect brain structure, chemistry and function of women in their reproductive age, potentially shaping their behavior... (Review)
Review
Increasing evidence indicates that ovarian hormones affect brain structure, chemistry and function of women in their reproductive age, potentially shaping their behavior and mental health. Throughout the reproductive years, estrogens and progesterone levels fluctuate across the menstrual cycle and can modulate neural circuits involved in affective and cognitive processes. Here, we review seventy-seven neuroimaging studies and provide a comprehensive and data-driven evaluation of the accumulating evidence on brain plasticity associated with endogenous ovarian hormone fluctuations in naturally cycling women (n = 1304). The results particularly suggest modulatory effects of ovarian hormones fluctuations on the reactivity and structure of cortico-limbic brain regions. These findings highlight the importance of performing multimodal neuroimaging studies on neural correlates of systematic ovarian hormone fluctuations in naturally cycling women based on careful menstrual cycle staging.
Topics: Brain; Estrogens; Female; Humans; Menstrual Cycle; Neuroimaging; Progesterone
PubMed: 33098847
DOI: 10.1016/j.yfrne.2020.100878