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BACKGROUND: Previous studies using resting-state functional neuroimaging have revealed alterations in whole-brain images, connectome-wide functional connectivity and graph-based metrics in groups of patients with schizophrenia relative to groups of healthy controls. However, it is unclear which of these measures best captures the neural correlates of this disorder at the level of the individual patient. METHODS: Here we investigated the relative diagnostic value of these measures. A total of 295 patients with schizophrenia and 452 healthy controls were investigated using resting-state functional Magnetic Resonance Imaging at five research centres. Connectome-wide functional networks were constructed by thresholding correlation matrices of 90 brain regions, and their topological properties were analyzed using graph theory-based methods. Single-subject classification was performed using three machine learning (ML) approaches associated with varying degrees of complexity and abstraction, namely logistic regression, support vector machine and deep learning technology. RESULTS: Connectome-wide functional connectivity allowed single-subject classification of patients and controls with higher accuracy (average: 81%) than both whole-brain images (average: 53%) and graph-based metrics (average: 69%). Classification based on connectome-wide functional connectivity was driven by a distributed bilateral network including the thalamus and temporal regions. CONCLUSION: These results were replicated across the three employed ML approaches. Connectome-wide functional connectivity permits differentiation of patients with schizophrenia from healthy controls at single-subject level with greater accuracy; this pattern of results is consistent with the 'dysconnectivity hypothesis' of schizophrenia, which states that the neural basis of the disorder is best understood in terms of system-level functional connectivity alterations.
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Encéfalo/fisiopatología , Conectoma , Esquizofrenia/diagnóstico por imagen , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Esquizofrenia/fisiopatología , Índice de Severidad de la Enfermedad , Máquina de Vectores de Soporte , Adulto JovenRESUMEN
Hepatic abscesses and hepatic metastasis are common diseases. However, hepatic abscesses seldom occur in patients with hepatic metastases. We describe a case of a 67-year-old female patient with abdominal pain in the right upper quadrant. Magnetic resonance imaging revealed several lesions, with the largest lesion displaying features of both hepatic pyogenic abscess and liver metastasis. These features included iso- or hypointense signaling on T1WI and T2WI, hyperintense signaling on diffusion weighted imaging of the thick wall, and mixed hyperintense signal in the center on DWI, as well as dramatic and irregular peripheral enhancement was detected on LAVA dynamic contrast scanning. Aspiration and culture of the largest lesions revealed Klebsiella pneumoniae and a pathologic diagnosis of adenocarcinoma. At this point, the patient admitted a history of colon adenocarcinoma 9 years ago treated with hemicolectomy. Therefore, this patient was considered to have a hepatic pyogenic abscesses complicated by hepatic metastasis. The patient began treatment for the responsible pathogens and underwent chemoembolization of the liver lesions. In special cases, we could attempt to pursue a more detailed search for coexistence of microorganism infection and tumor.
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BACKGROUND@#Patients with schizophrenia (SCZ) and major depressive disorder (MDD) share significant clinical overlap, although it remains unknown to what extent this overlap reflects shared neural profiles. To identify the shared and specific abnormalities in SCZ and MDD, we performed a whole-brain voxel-based meta-analysis using magnetization transfer imaging, a technique that characterizes the macromolecular structural integrity of brain tissue in terms of the magnetization transfer ratio (MTR).@*METHODS@#A systematic search based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in PubMed, EMBASE, International Scientific Index (ISI) Web of Science, and MEDLINE for relevant studies up to March 2022. Two researchers independently screened the articles. Rigorous scrutiny and data extraction were performed for the studies that met the inclusion criteria. Voxel-wise meta-analyses were conducted using anisotropic effect size-signed differential mapping with a unified template. Meta-regression was used to explore the potential effects of demographic and clinical characteristics.@*RESULTS@#A total of 15 studies with 17 datasets describing 365 SCZ patients, 224 MDD patients, and 550 healthy controls (HCs) were identified. The conjunction analysis showed that both disorders shared higher MTR than HC in the left cerebellum ( P =0.0006) and left fusiform gyrus ( P =0.0004). Additionally, SCZ patients showed disorder-specific lower MTR in the anterior cingulate/paracingulate gyrus, right superior temporal gyrus, and right superior frontal gyrus, and higher MTR in the left thalamus, precuneus/cuneus, posterior cingulate gyrus, and paracentral lobule; and MDD patients showed higher MTR in the left middle occipital region. Meta-regression showed no statistical significance in either group.@*CONCLUSIONS@#The results revealed a structural neural basis shared between SCZ and MDD patients, emphasizing the importance of shared neural substrates across psychopathology. Meanwhile, distinct disease-specific characteristics could have implications for future differential diagnosis and targeted treatment.
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Humanos , Trastorno Depresivo Mayor/tratamiento farmacológico , Esquizofrenia/patología , Encéfalo/patología , Corteza Prefrontal , Lóbulo Frontal , Imagen por Resonancia Magnética/métodosRESUMEN
Precisely delivering combinational therapeutic agents has become a crucial challenge for anti-tumor treatment. In this study, a novel redox-responsive polymeric prodrug (molecular weight, MW: 93.5 kDa) was produced by reversible addition-fragmentation chain transfer (RAFT) polymerization. The amphiphilic block polymer-doxorubicin (DOX) prodrug was employed to deliver a hydrophobic photosensitizer (PS), chlorin e6 (Ce6), and the as-prepared nanoscale system [NPs(Ce6)] was investigated as a chemo-photodynamic anti-cancer agent. The glutathione (GSH)-cleavable disulfide bond was inserted into the backbone of the polymer for biodegradation inside tumor cells, and DOX conjugated onto the polymer with a disulfide bond was successfully released intracellularly. NPs(Ce6) released DOX and Ce6 with their original molecular structures and degraded into segments with low MWs of 41.2 kDa in the presence of GSH. NPs(Ce6) showed a chemo-photodynamic therapeutic effect to kill 4T1 murine breast cancer cells, which was confirmed from a collapsed cell morphology, a lifted level in the intracellular reactive oxygen species, a reduced viability and induced apoptosis. Moreover, ex vivo fluorescence images indicated that NPs(Ce6) retained in the tumor, and exhibited a remarkable in vivo anticancer efficacy. The combinational therapy showed a significantly increased tumor growth inhibition (TGI, 58.53%). Therefore, the redox-responsive, amphiphilic block polymeric prodrug could have a great potential as a chemo-photodynamic anti-cancer agent.
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Major depressive disorder (MDD) causes great decrements in health and quality of life with increments in healthcare costs, but the causes and pathogenesis of depression remain largely unknown, which greatly prevent its early detection and effective treatment. With the advancement of neuroimaging approaches, numerous functional and structural alterations in the brain have been detected in MDD and more recently attempts have been made to apply these findings to clinical practice. In this review, we provide an updated summary of the progress in translational application of psychoradiological findings in MDD with a specified focus on potential clinical usage. The foreseeable clinical applications for different MRI modalities were introduced according to their role in disorder classification, subtyping, and prediction. While evidence of cerebral structural and functional changes associated with MDD classification and subtyping was heterogeneous and/or sparse, the ACC and hippocampus have been consistently suggested to be important biomarkers in predicting treatment selection and treatment response. These findings underlined the potential utility of brain biomarkers for clinical practice.
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Humanos , Encéfalo/diagnóstico por imagen , Trastorno Depresivo Mayor/diagnóstico por imagen , Imagen por Resonancia Magnética , Neuroimagen , Calidad de VidaRESUMEN
This study aimed to define the most consistent white matter microarchitecture pattern in Parkinson's disease (PD) reflected by fractional anisotropy (FA), addressing clinical profiles and methodology-related heterogeneity. Web-based publication databases were searched to conduct a meta-analysis of whole-brain diffusion tensor imaging studies comparing PD with healthy controls (HC) using the anisotropic effect size-signed differential mapping. A total of 808 patients with PD and 760 HC coming from 27 databases were finally included. Subgroup analyses were conducted considering heterogeneity with respect to medication status, disease stage, analysis methods, and the number of diffusion directions in acquisition. Compared with HC, patients with PD had decreased FA in the left middle cerebellar peduncle, corpus callosum (CC), left inferior fronto-occipital fasciculus, and right inferior longitudinal fasciculus. Most of the main results remained unchanged in subgroup meta-analyses of medicated patients, early stage patients, voxel-based analysis, and acquisition with 30 diffusion directions. The subgroup meta-analysis of medication-free patients showed FA decrease in the right olfactory cortex. The cerebellum and CC, associated with typical motor impairment, showed the most consistent FA decreases in PD. Medication status, analysis approaches, and the number of diffusion directions have an important impact on the findings, needing careful evaluation in future meta-analyses.
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Humanos , Anisotropía , Encéfalo/diagnóstico por imagen , Cuerpo Calloso , Imagen de Difusión Tensora , Enfermedad de Parkinson/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagenRESUMEN
Multi-modal therapeutics are emerging for simultaneous diagnosis and treatment of cancer. Polymeric carriers are often employed for loading multiple drugs due to their versatility and controlled release of these drugs in response to a tumor specific microenvironment. A theranostic nanomedicine was designed and prepared by complexing a small gadolinium chelate, conjugating a chemotherapeutic drug PTX through a cathepsin B-responsive linker and covalently bonding a fluorescent probe pheophorbide a (Ppa) with a branched glycopolymer. The branched prodrug-based nanosystem was degradable in the tumor microenvironment with overexpressed cathepsin B, and PTX was simultaneously released to exert its therapeutic effect. The theranostic nanomedicine, branched glycopolymer-PTX-DOTA-Gd, had an extended circulation time, enhanced accumulation in tumors, and excellent biocompatibility with significantly reduced gadolinium ion (Gd
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Objective:To explore the efficiency of MR psychoradiology examination in screening and classification of psychiatric disorders as well as its potential clinical application.Methods:Retrospective study was conducted for 144 patients with MR psychoradiology examination, who were diagnosed mental disorders based on International Statistical Classification of Diseases and Related Health Problems Tenth Revision (ICD-10) from September 2018 to July 2020 in West China Hospital of Sichuan University. As our previous studies, imaging diagnostic models were constructed based on gray matter volume (GMV) analysis for four kinds of psychiatric disorders, including depression, anxiety disorder, bipolar disorder and schizophrenia. For 120 patients with psychiatric disorders, the GMV change pattern of brain regions was detected and subtyped by MR psychoradiology examination with 50% similarity threshold of the above imaging diagnostic models. The diagnostic efficiency of MR psychoradiology examination was evaluated with references of clinical diagnose. For 24 patients with dementia, brain atrophy was additionally measured by conventional MR examination and MR psychoradiology examination respectively.Results:The sensitivity, specificity, Youden index and accuracy of MR psychoradiology in identifying the four psychiatric disorders were 86.6% (84/97), 69.6% (16/23), 0.56 and 83.3% (100/120), including depression [77.8% (28/36), 69.0% (58/84), 0.47, 71.7% (86/120)], schizophrenia [58.8% (10/17), 91.3% (94/103), 0.50, 86.7% (104/120)], bipolar disorder [42.1% (8/19), 96.0% (97/101), 0.38, 87.5% (105/120)] and anxiety disorder [24.0% (6/25), 100% (95/95), 0.24, 84.2% (101/120)]. As for 24 patients with dementia, 58.3% (14/24) were detected with brain atrophy by conventional MR examination, while 91.7% (22/24) were detected by MR psychoradiology examination.Conclusions:MR psychoradiology can detect the subtle brain structural abnormalities of patients with mental disorders. Although it can′t be used as an independent biomarker for disease diagnosis till now, it is of great help in improving the accuracy and objectivity of diagnosis.
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Asthma is a serious health problem that involves not only the respiratory system but also the central nervous system. Previous studies identified either regional or network alterations in patients with asthma, but inconsistent results were obtained. A key question remains unclear: are the regional and neural network deficits related or are they two independent characteristics in asthma? Answering this question is the aim of this study. By collecting resting-state functional magnetic resonance imaging from 39 patients with asthma and 40 matched health controls, brain functional measures including regional activity (amplitude of low-frequency fluctuations) and neural network function (degree centrality (DC) and functional connectivity) were calculated to systematically characterize the functional alterations. Patients exhibited regional abnormities in the left angular gyrus, right precuneus, and inferior temporal gyrus within the default mode network. Network abnormalities involved both the sensorimotor network and visual network with key regions including the superior frontal gyrus and occipital lobes. Altered DC in the lingual gyrus was correlated with the degree of airway obstruction. This study elucidated different patterns of regional and network changes, thereby suggesting that the two parameters reflect different brain characteristics of asthma. These findings provide evidence for further understanding the potential cerebral alterations in the pathophysiology of asthma.
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Humanos , Asma/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Imagen por Resonancia MagnéticaRESUMEN
Depression is a common psychiatric disorder, and approximately 30% patients with depression do not respond effectively to standard antidepressant medication; this condition is termed treatment resistant depression (TRD) and its neurobiological mechanism remains unclear. Neuroimaging techniques can non-invasively explore changes in brain structure, function and metabolism. These techniques have been applied in neurobiological research of TRD and revealed critical abnormalities in brain structure, function and metabolism in fronto-limbic system. In this paper, we reviewed the latest progress in neuroimaging researches on TRD, providing new insight and imaging evidence for further neurobiological studies of TRD.
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In the current study, we aim to investigate whether post-traumatic stress disorder (PTSD) is associated with structural alterations in specific subfields of hippocampus comparing with trauma-exposed control (TC) in a relatively large sample. We included 67 PTSD patients who were diagnosed under Diagnostic and Statistical Manual of Mental Disorders (4th Edition) (DSM-Ⅳ) criteria and 78 age- and sex-matched non-PTSD adult survivors who experienced similar stressors. High resolution T1 weighted images were obtained via a GE 3.0 T scanner. The structural data was automatically segmented using FreeSurfer software, and volume of whole hippocampus and subfield including CA1, CA2-3, CA4-DG, fimbria, presubiculum, subiculum and fissure were extracted. Volume differences between the two groups were statistically compared with age, years of education, duration from the events and intracranial volume (ICV) as covariates. Hemisphere, sex and diagnosis were entered as fixed factors. Relationship between morphometric measurements with Clinician-Administered PTSD Scale (CAPS) score and illness duration were performed using Pearson's correlation with SPSS. Comparing to TC, PTSD patients showed no statistically significant alteration in volumes of the whole hippocampus and all the subfields ( > 0.05). In male patients, there were significant correlations between CAPS score and volume of right CA2-3 ( = 0.197, = 0.034), right subiculum ( = 0.245, = 0.016), and duration statistically correlated with right fissure ( = 0.247, = 0.016). In female patients, CAPS scores significant correlated with volume of left presubiculum ( = 0.095, = 0.042), left subiculum ( = 0.090, = 0.048), and left CA4-DG ( = 0.099, = 0.037). The main findings of the current study suggest that stress event causes non-selective damage to hippocampus in both PTSD patients and TC, and gender-specific lateralization may underlie PTSD pathology.
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Objective Present study aimed to characterize the alteration of cortical thickness in first-episode, never-medicated, adult patients with major depressive disorder (MDD), and explore whether such deficits were related with their disease duration and clinical symptom severity. Methods Thirty-seven adult MDD patients were recruited from March 2013 to August 2015 as patient group, and 41 healthy volunteers were as control group. All the patients underwent three-dimensional spoiled gradient recalled (3D-SPGR) sequences, and the images were acquired. Constructions of the cortical surface were developed from 3D-SPGR images using FreeSurfer software, and the thickness of the entire cortex was measured according to the automated surface reconstruction, transformation, and high-resolution inter-subject alignment procedures. Finally, cortical thickness was compared between the two groups, and the relativity between clinical symptom severity, disease progression and clinical scores were analyzed using the General Linear Model (GLM). Results Our results revealed a significant increase in cortical thickness(P0.05). Conclusion Excluding the impact of treatment, our study showed that the cortical thickness change was mainly located in the prefrontal-limbic system in the in early course of MDD.
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OBJECTIVE: We hypothesize that the amplitude of low-frequency fluctuations (ALFF) is involved in the altered regional baseline brain function in social anxiety disorder (SAD). The aim of the study was to analyze the altered baseline brain activity in drug-naive adult patients with SAD. METHODS: We investigated spontaneous and baseline brain activities by obtaining the resting-state functional magnetic resonance imaging data of 20 drug-naive adult SAD patients and 19 healthy controls. Voxels were used to analyze the ALFF values using one- and two-sample t-tests. A post-hoc correlation of clinical symptoms was also performed. RESULTS: Our findings show decreased ALFF in the bilateral insula, left medial superior frontal gyrus, left precuneus, left middle temporal gyrus, right middle temporal pole, and left fusiform gyrus of the SAD group. The SAD patients exhibited significantly increased ALFF in the right inferior temporal gyrus, right middle temporal gyrus, bilateral middle occipital gyrus, orbital superior frontal gyrus, right fusiform gyrus, right medial superior frontal gyrus, and left parahippocampal gyrus. Moreover, the Liebowitz Social Anxiety Scale results for the SAD patients were positively correlated with the mean Z values of the right middle occipital and right inferior occipital but showed a negative correlation with the mean Z values of the right superior temporal gyrus and right medial superior frontal gyrus. CONCLUSION: These results of the altered regional baseline brain function in SAD suggest that the regions with abnormal spontaneous activities are involved in the underlying pathophysiology of SAD patients.
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Adulto , Humanos , Ansiedad , Trastornos de Ansiedad , Encéfalo , Imagen por Resonancia Magnética , Órbita , Giro ParahipocampalRESUMEN
BACKGROUND/AIMS: Increasing evidence shows involvement of psychological disorders in functional dyspepsia (FD), but how psychological factors exert their influences upon FD remains largely unclear. The purpose of the present study was to explore the brain-based correlations of psychological factors and FD. METHODS: Based on Fluorine-18-deoxyglucose positron emission tomography-computed tomography, the altered cerebral glycometabolism was investigated in 40 FD patients compared with 20 healthy controls during resting state using statistical parametric mapping software. RESULTS: FD patients exhibited increased glucose metabolism in multiple regions relative to controls (P < 0.001, family-wise error corrected). After controlling for the dyspeptic symptoms, increased aberrations persisted within the insula, anterior cingulate cortex (ACC), middle cingulate cortex (MCC) and middle frontal cortex (midFC), which was related to anxiety and depression score. Interestingly, FD patients without anxiety/depression symptoms also showed increased glycometabolism within the insula, ACC, MCC and midFC. Moreover, FD patients with anxiety/depression symptoms exhibited more significant hypermetabolism within the above 4 sites compared with patients without anxiety/depression symptoms. CONCLUSIONS: Our results suggested that the altered cerebral glycometabolism may be in a vicious cycle of psychological vulnerabilities and increased gastrointestinal symptoms.
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Humanos , Ansiedad , Corteza Cerebral , Depresión , Dispepsia , Electrones , Glucosa , Giro del Cíngulo , Metabolismo , PsicologíaRESUMEN
Post-traumatic stress disorder (PTSD) is a mental disorder causing great distress to individuals, families and even society, and there is not yet effective way of unified prevention and treatment up till now. Lots of neuroimaging techniques, however, such as the magnetic resonance imaging, are widely used to the study of the pathogenesis of PTSD with the development of medical imaging. Functional magnetic resonance imaging (fMRI) can be applied to detect the abnormalities not only of the brain morphology but also of the function of various cerebral areas and neural circuit, and plays an important role in studying the pathogenesis of psychiatric diseases. In this paper, we mainly review the task-related and resting-state functional magnetic resonance imaging studies of the PTSD, and finally suggest possible directions for future research.
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Humanos , Encéfalo , Imagen por Resonancia Magnética , Neuroimagen , Trastornos por Estrés PostraumáticoRESUMEN
Objective To evaluate the clinical value of whole-brain diffusion tensor imaging(DTI) in diagnosing patients with social anxiety disorder(SAD) using an automated method based on support vector machine(SVM) classification.Methods Whole brain DTI data were collected from 19 patients with SAD and 19 age-,gender-and education-matched healthy control(HC) subjects.Fractional anisotropy(FA) of whole brain was obtained by input all tensor images into Diffusion Toolkit software.Based upon the characteristics of brain FA,the pattern recognition of brain image data(PROBID) toolbox on the grounds of SVM algorithm was employed to classify the subjects,evaluate the diagnostic value of whole-brain FA data based SVM in diagnosing SAD patients and verify the robustness of the diagnostic results using permutation test with the threshold at P≤0.001.The weight vector score of each voxel was calculated according to the ratio between this voxel and whole brain in FA differences of the two groups.The white matter regions identified by setting the threshold to the top 30% of the weight vector scores with at least 10 contiguous voxels were demonstrated by MRIcro software.Results Diagnostic accuracy of whole-brain FA based SVM in diagnosing SAD was 92.11% (35/38) in which the specificity was 94.44% (17/18),the sensitivity was 90.00%(18/20),the positive likelihood ratio was 17.01,the negative likelihood ratio was 0.11 and the diagnostic index was 184.22%.Permutation test suggested that the diagnostic results were significantly reliable.White matter regions showing major contributions favoring SAD over HC were located in the genu and splenium of the corpus callosum,the left uncinate fasciculus,the left inferior longitudinal fasciculus,the left inferior fronto-occipital fasciculus,bilateral frontal gyri and the left occipital lobe.Whereas,white matter in bilateral anterior cingula,the left middle cerebellar peduncle and the left inferior parietal lobule showed more contributions to diagnose HC than to diagnose SAD.Conclusions As whole brain FA data based on SVM showing a high accuracy in diagnosing SAD,brain DTI characteristics have the potential to be the specific indicators in the diagnosis of SAD.SVM might be used as a tool to verify the reliability of white matter abnormalities and provide regions of interest in DTI study of neurological and psychiatric diseases.
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This study was aimed to optimize the methods of magnetic resonance spectroscopy (MRS) to improve its quality in amygdala. Forty-three volunteers were examined at right and left amygdala using stimulated-echo acquisition mode (STEAM), and point-resolved spectroscopy series (PRESS) with and without saturation bands. The Cr-SNR, water-suppression level, water full width at half maximum (FWHM) and RMS noise of three sequences were compared. The results showed that (1) the Cr-SNR and water-suppression lelvel of PRESS with saturation bands were better than that of PRESS without saturation bands and STEAM (P<0.001); (2) the left and right RMS noise was significantly different both using PRESS with saturation bands and using STEAM (P<0.05); (3) there was a positive, significant correlation between Cr-SNR and voxel size (P<0.05). Therefore, PRESS with saturation bands is better than PRESS without saturation bands or STEAM for the spectroscopy of amygdala. It is also useful to make the voxel as big as possible to improve the spectral quality.
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Adulto , Femenino , Humanos , Masculino , Adulto Joven , Algoritmos , Amígdala del Cerebelo , Metabolismo , Fisiología , Artefactos , Espectroscopía de Resonancia Magnética , Métodos , Reconocimiento de Normas Patrones Automatizadas , Estándares de ReferenciaRESUMEN
In this paper, a new method of combining translation invariant (TI) and wavelet-threshold (WT) algorithm to distinguish weak and overlapping signals of proton magnetic resonance spectroscopy (1H-MRS) is presented. First, the 1H-MRS spectrum signal is transformed into wavelet domain and then its wavelet coefficients are obtained. Then, the TI method and WT method are applied to detect the weak signals overlapped by the strong ones. Through the analysis of the simulation data, we can see that both frequency and amplitude information of small-signals can be obtained accurately by the algorithm, and through the combination with the method of signal fitting, quantitative calculation of the area under weak signals peaks can be realized.
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Algoritmos , Simulación por Computador , Espectroscopía de Resonancia Magnética , Métodos , Protones , Procesamiento de Señales Asistido por Computador , Análisis de OndículasRESUMEN
Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. Alterations in GABAergic function are associated with a variety of neurological and psychiatric disorders. However, noninvasive in vivo measurement of GABA is difficult because of its low concentration and the presence of overlapping resonances. To study GABA concentration in the occipital cortex in major depressive disorder (MDD), a group of medication-naive, first episode depressed patients (n = 18, HAMD > 17), and a group of healthy controls (n = 23) were investigated using a Point Resolved Spectroscopy (MEGA-PRESS) on a 3.0 T MR scanner. The results showed that occipital GABA levels were significantly lower (P < 0.001) in the patient group than those in the healthy controls, yet the correlations between the severity of MDD (HAMD, BDI) and the GABA concentration is insignificant. Therefore, our data suggest that patients with first episode, unmedicated MDD have changes in cortical concentrations of GABA. This biochemical abnormality may be a marker of a trait vulnerability to mood disorder, and may explain the visual problem of severe MDD patients.
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Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Trastorno Depresivo Mayor , Metabolismo , Espectroscopía de Resonancia Magnética , Lóbulo Occipital , Metabolismo , Ácido gamma-Aminobutírico , MetabolismoRESUMEN
ObjectiveTo investigate the change in brain functional magnetic resonance imaging (fMRI)during noxious electric stimu lation of forepaw and tail in rats.MethodsForty-eight healthy SD rats of both sexes weighing 300-450 g which responded sensitively to electrical stimulation as shown by Y-maze were randomly divided into 2 groups ( n =24 each) receiving nociceptive electric stimulation of left forepaw (group LF) and tail (group T) respectively.The animals were anesthetized with intraperitoneal 10% chloral hydrate 250-300 mg/kg.Brain fMRI was performed at 30 min after disappearance of righting reflex in both groups when electric stimulations were delivered intermittently to forepaw or tail.The images were analyzed with SPM2 software.ResultsPrimary and secondary somatosensory cortex,posterior cingutate cortex,amygdaloid nucleus and ventral posterolateral thalamic nucleus were activated in group T.Right accumbens nucleus,right primary somatosensory cortex,right ventral posterolateral thalamic nucleus and right posterior cingutate cortex were activated in group LF.ConclusionDifferent brain areas are activated by noxious electric stimulation of different parts of body as shown by brain fMRI.