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1.
Brain Connect ; 14(6): 340-350, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38874981

RESUMO

Background: The basal ganglia-thalamocortical (BGTC) and cerebello-thalamocortical (CTC) networks are implicated in tremor genesis; however, exact contributions across disorders have not been studied. Objective: Evaluate the structural connectivity of BGTC and CTC in tremor-dominant Parkinson's disease (TDPD) and essential tremor plus (ETP) with the aid of probabilistic tractography and graph theory analysis. Methods: Structural connectomes of the BGTC and CTC were generated by probabilistic tractography for TDPD (n = 25), ETP (ET with rest tremor, n = 25), and healthy control (HC, n = 22). The Brain Connectivity Toolbox was used for computing standard topological graph measures of segregation, integration, and centrality. Tremor severity was ascertained using the Fahn-Tolosa-Marin tremor rating scale (FTMRS). Results: There was no difference in total FTMRS scores. Compared with HC, TDPD had a lower global efficiency and characteristic path length. Abnormality in segregation, integration, and centrality of bilateral putamen, globus pallidus externa (GPe), and GP interna (GPi), with reduction of centrality of right caudate and cerebellar lobule 8, was observed. ETP showed reduction in segregation and integration of right GPe and GPi, ventrolateral posterior nucleus, and centrality of right putamen, compared with HC. Differences between TDPD and ETP were a reduction of strength of the right putamen, and lower clustering coefficient, local efficiency, and strength of the left GPi in TDPD. Conclusions: Contrary to expectations, TDPD and ETP may not be significantly different with regard to tremor pathogenesis, with definite overlaps. There may be fundamental similarities in network disruption across different tremor disorders with the same tremor activation patterns, along with disease-specific changes.


Assuntos
Imagem de Tensor de Difusão , Tremor Essencial , Vias Neurais , Doença de Parkinson , Humanos , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/fisiopatologia , Tremor Essencial/diagnóstico por imagem , Tremor Essencial/fisiopatologia , Tremor Essencial/patologia , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Imagem de Tensor de Difusão/métodos , Vias Neurais/fisiopatologia , Vias Neurais/diagnóstico por imagem , Conectoma/métodos , Tremor/diagnóstico por imagem , Tremor/fisiopatologia , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/fisiopatologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Cerebelo/patologia , Tálamo/diagnóstico por imagem , Tálamo/fisiopatologia
2.
Cancer Biother Radiopharm ; 39(5): 349-357, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38324045

RESUMO

Background: Amino acid positron emission tomography (PET) imaging plays a significant role in the diagnosis of gliomas and in differentiating tumor recurrence from necrosis. In this study, the authors evaluated the diagnostic efficacy of [99mTc]Tc-methionine single-photon emission computed tomography-computed tomography (SPECT-CT) in comparison with [11C]methionine PET-magnetic resonance imaging (MRI) in delineating tumors. Methods: Thirty-one (primary: 16 and postoperative: 15) patients of confirmed (either MRI or histopathological proven) glioma underwent both [99mTc]Tc-methionine SPECT-CT and [11C]methionine PET-MRI. A comparative analysis was performed between SPECT, PET, and MR images to calculate the concordance between the modalities and to evaluate the diagnostic efficacy of the [99mTc]Tc-methionine SPECT. Results: [99mTc]Tc-methionine SPECT showed comparable uptake in the tumor lesions in comparison to [11C]methionine PET. A significant and strong positive correlation was observed between the volume of tumor (Vt) in PET and Vt MR (p < 0.004). Likewise, a significant and strong positive correlation was found between Vt SPECT and Vt MR. [99mTc]-methionine has a sensitivity and specificity of 91% and 75%, respectively, compared with 82% and 100% for [11C]methionine in postoperative cases to differentiate the tumor recurrence from necrosis. The sensitivity and specificity of [99mTc]Tc-methionine was 92% and 100%, respectively, compared with 92% and 67% for [11C]methionine in primary tumors. Conclusion: [99mTc]Tc-methionine SPECT-CT is as equally good as [11C]methionine for diagnosing and differentiating it from necrosis especially in high-grade glioma.


Assuntos
Neoplasias Encefálicas , Glioma , Imageamento por Ressonância Magnética , Metionina , Humanos , Glioma/diagnóstico por imagem , Glioma/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética/métodos , Adulto , Neoplasias Encefálicas/diagnóstico por imagem , Idoso , Compostos Radiofarmacêuticos/farmacologia , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos de Carbono , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto Jovem , Compostos de Organotecnécio/administração & dosagem , Imagem Multimodal/métodos
3.
Cancers (Basel) ; 15(18)2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37760422

RESUMO

PURPOSE: The isocitrate dehydrogenase (IDH) mutation has become one of the most important prognostic biomarkers in glioma management, indicating better treatment response and prognosis. IDH mutations confer neomorphic activity leading to the conversion of alpha-ketoglutarate (α-KG) to 2-hydroxyglutarate (2HG). The purpose of this study was to investigate the clinical potential of proton MR spectroscopy (1H-MRS) in identifying IDH-mutant gliomas by detecting characteristic resonances of 2HG and its complex interplay with other clinically relevant metabolites. MATERIALS AND METHODS: Thirty-two patients with suspected infiltrative glioma underwent a single-voxel (SVS, n = 17) and/or single-slice-multivoxel (1H-MRSI, n = 15) proton MR spectroscopy (1H-MRS) sequence with an optimized echo-time (97 ms) on 3T-MRI. Spectroscopy data were analyzed using the linear combination (LC) model. Cramér-Rao lower bound (CRLB) values of <40% were considered acceptable for detecting 2HG and <20% for other metabolites. Immunohistochemical analyses for determining IDH mutational status were subsequently performed from resected tumor specimens and findings were compared with the results from spectral data. Mann-Whitney and chi-squared tests were performed to ascertain differences in metabolite levels between IDH-mutant and IDH-wild-type gliomas. Receiver operating characteristic (ROC) curve analyses were also performed. RESULTS: Data from eight cases were excluded due to poor spectral quality or non-tumor-related etiology, and final data analyses were performed from 24 cases. Of these cases, 9/12 (75%) were correctly identified as IDH-mutant or IDH-wildtype gliomas through SVS and 10/12 (83%) through 1H-MRSI with an overall concordance rate of 79% (19/24). The sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 77%, 86%, and 70%, respectively. The metabolite 2HG was found to be significant in predicting IDH-mutant gliomas through the chi-squared test (p < 0.01). The IDH-mutant gliomas also had a significantly higher NAA/Cr ratio (1.20 ± 0.09 vs. 0.75 ± 0.12 p = 0.016) and lower Glx/Cr ratio (0.86 ± 0.078 vs. 1.88 ± 0.66; p = 0.029) than those with IDH wild-type gliomas. The areas under the ROC curves for NAA/Cr and Glx/Cr were 0.808 and 0.786, respectively. CONCLUSIONS: Noninvasive optimized 1H-MRS may be useful in predicting IDH mutational status and 2HG may serve as a valuable diagnostic and prognostic biomarker in patients with gliomas.

4.
Eur J Neurosci ; 54(6): 6093-6103, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34340255

RESUMO

To relate individual differences in music perception ability with whole brain white matter connectivity, we scanned a group of 27 individuals with varying degrees of musical training and assessed musical ability in sensory and sequential music perception domains using the Profile of Music Perception Skills-Short version (PROMS-S). Sequential processing ability was estimated by combining performance on tasks for Melody, Standard Rhythm, Embedded Rhythm, and Accent subscores while sensory processing ability was ascertained via tasks of Tempo, Pitch, Timbre, and Tuning. Controlling for musical training, gender, and years of training, network-based statistics revealed positive linear associations between total PROMS-S scores and increased interhemispheric fronto-temporal and parieto-frontal white matter connectivity, suggesting a distinct segregated structural network for music perception. Secondary analysis revealed two subnetworks for sequential processing ability, one comprising ventral fronto-temporal and subcortical regions and the other comprising dorsal fronto-temporo-parietal regions. A graph-theoretic analysis to characterize the structural network revealed a positive association of modularity of the whole brain structural connectome with the d' total score. In addition, the nodal degree of the right posterior cingulate cortex also showed a significant positive correlation with the total d' score. Our results suggest that a distinct structural network of connectivity across fronto-temporal, cerebellar, and cerebro-subcortical regions is associated with music processing abilities and the right posterior cingulate cortex mediates the connectivity of this network.


Assuntos
Música , Substância Branca , Percepção Auditiva , Encéfalo/diagnóstico por imagem , Humanos , Lobo Parietal , Percepção , Percepção da Altura Sonora , Substância Branca/diagnóstico por imagem
5.
IEEE Trans Biomed Eng ; 68(12): 3628-3637, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33989150

RESUMO

OBJECTIVE: The larger sample sizes available from multi-site publicly available neuroimaging data repositories makes machine-learning based diagnostic classification of mental disorders more feasible by alleviating the curse of dimensionality. However, since multi-site data are aggregated post-hoc, i.e. they were acquired from different scanners with different acquisition parameters, non-neural inter-site variability may mask inter-group differences that are at least in part neural in origin. Hence, the advantages gained by the larger sample size in the context of machine-learning based diagnostic classification may not be realized. METHODS: We address this issue using harmonization of multi-site neuroimaging data using the ComBat technique, which is based on an empirical Bayes formulation to remove inter-site differences in data distributions, to improve diagnostic classification accuracy. Specifically, we demonstrate this using ABIDE (Autism Brain Imaging Data Exchange) multi-site data for classifying individuals with Autism from healthy controls using resting state fMRI-based functional connectivity data. RESULTS: Our results show that higher classification accuracies across multiple classification models can be obtained (especially for models based on artificial neural networks) from multi-site data post harmonization with the ComBat technique as compared to without harmonization, outperforming earlier results from existing studies using ABIDE. Furthermore, our network ablation analysis facilitated important insights into autism spectrum disorder pathology and the connectivity in networks shown to be important for classification covaried with verbal communication impairments in Autism. CONCLUSION: Multi-site data harmonization using ComBat improves neuroimaging-based diagnostic classification of mental disorders. SIGNIFICANCE: ComBat has the potential to make AI-based clinical decision-support systems more feasible in psychiatry.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Transtorno do Espectro Autista/diagnóstico por imagem , Transtorno Autístico/diagnóstico por imagem , Teorema de Bayes , Encéfalo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética
6.
Eur Radiol ; 31(11): 8218-8227, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33945022

RESUMO

OBJECTIVES: This study aimed to explore the feasibility of radiomics features extracted from T1-weighted MRI images to differentiate Parkinson's disease (PD) from atypical parkinsonian syndromes (APS). METHODS: Radiomics features were computed from T1 images of 65 patients with PD, 61 patients with APS (31: progressive supranuclear palsy and 30: multiple system atrophy), and 75 healthy controls (HC). These features were extracted from 19 regions of interest primarily from subcortical structures, cerebellum, and brainstem. Separate random forest classifiers were applied to classify different groups based on a reduced set of most important radiomics features for each classification as determined by the random forest-based recursive feature elimination by cross-validation method. RESULTS: The PD vs HC classifier illustrated an accuracy of 70%, while the PD vs APS classifier demonstrated a superior test accuracy of 92%. Moreover, a 3-way PD/MSA/PSP classifier performed with 96% accuracy. While first-order and texture-based differences like Gray Level Co-occurrence Matrix (GLCM) and Gray Level Difference Matrix for the substantia nigra pars compacta and thalamus were highly discriminative for PD vs HC, textural features mainly GLCM of the ventral diencephalon were highlighted for APS vs HC, and features extracted from the ventral diencephalon and nucleus accumbens were highlighted for the classification of PD and APS. CONCLUSIONS: This study establishes the utility of radiomics to differentiate PD from APS using routine T1-weighted images. This may aid in the clinical diagnosis of PD and APS which may often be indistinguishable in early stages of disease. KEY POINTS: • Radiomics features were extracted from T1-weighted MRI images. • Parkinson's disease and atypical parkinsonian syndromes were classified at an accuracy of 92%. • This study establishes the utility of radiomics to differentiate Parkinson's disease and atypical parkinsonian syndromes using routine T1-weighted images.


Assuntos
Atrofia de Múltiplos Sistemas , Doença de Parkinson , Transtornos Parkinsonianos , Paralisia Supranuclear Progressiva , Humanos , Imageamento por Ressonância Magnética , Atrofia de Múltiplos Sistemas/diagnóstico por imagem , Doença de Parkinson/diagnóstico por imagem , Transtornos Parkinsonianos/diagnóstico por imagem , Paralisia Supranuclear Progressiva/diagnóstico por imagem
7.
Acta Neurol Scand ; 143(4): 430-440, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33175396

RESUMO

OBJECTIVES: Progressive supranuclear palsy-Richardson syndrome (PSP-RS) is characterized by symmetrical parkinsonism with postural instability and frontal dysfunction. This study aims to use the whole brain structural connectome (SC) to gain insights into the underlying disconnectivity which may be implicated in the clinical features of PSP-RS. METHODS: Sixteen patients of PSP-RS and 12 healthy controls were recruited. Disease severity was quantified using PSP rating scale (PSPRS), and mini-mental scale was applied to evaluate cognition. Thirty-two direction diffusion MRIs were acquired and used to compute the structural connectome of the whole brain using deterministic fiber tracking. Group analyses were performed at the edge-wise, nodal, and global levels. Age and gender were used as nuisance covariates for all the subsequent analyses, and FDR correction was applied. RESULTS: Network-based statistics revealed a 34-edge network with significantly abnormal edge-wise connectivity in the patient group. Of these, 25 edges were cortical connections, of which 68% were frontal connections. Abnormal deep gray matter connections were predominantly comprised of connections between structures of the basal ganglia. The characteristic path length of the SC was lower in PSP-RS, and nodal analysis revealed abnormal degree, strength, local efficiency, betweenness centrality, and participation coefficient in several nodes. CONCLUSIONS: Significant alterations in the structural connectivity of the whole brain connectome were observed in PSP-RS. The higher degree of abnormality observed in nodes belonging to the frontal lobe and basal ganglia substantiates the predominant frontal dysfunction and parkinsonism observed in PSP-RS. The findings of this study support the concept that PSP-RS may be a network-based disorder.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/métodos , Rede Nervosa/diagnóstico por imagem , Paralisia Supranuclear Progressiva/diagnóstico por imagem , Idoso , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/fisiopatologia , Encéfalo/fisiopatologia , Estudos de Coortes , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/fisiopatologia , Estudos Retrospectivos , Paralisia Supranuclear Progressiva/fisiopatologia
8.
Brain Struct Funct ; 224(5): 1711-1722, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30949766

RESUMO

Music perceptual abilities are subjective and exhibit high inter-individual variability. Twenty-nine participants with varying degrees of musical training were tested for musical perception ability with the Profile of Music Perception Skills (PROMS) and brain structural measures obtained via diffusion tensor imaging. Controlling for the period of training, TBSS results showed that individuals with better musical perception abilities showed increased deviations from linear anisotropy in the corpus callosum. Specifically, mode of anisotropy in the genu and body of the corpus callosum was negatively correlated with music perception score suggesting the presence of crossing fibers. A multi-compartment model of crossing fibers revealed a significant positive relation for partial volumes of secondary fiber populations with timing aspects of music perception. Our results suggest that inter-hemispheric connectivity differences in the anterior parts of the corpus callosum may reflect innate differences in the processing of the rhythmic aspects of music.


Assuntos
Corpo Caloso/fisiologia , Processamento de Imagem Assistida por Computador , Música , Percepção/fisiologia , Adulto , Anisotropia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Individualidade , Masculino , Periodicidade , Adulto Jovem
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