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Susceptibility weighted imaging: differentiating between calcification and hemosiderin

Jeam Haroldo Oliveira Barbosa, Antonio Carlos Santos, Carlos Ernesto Garrido Salmon
2015 Radiologia Brasileira  
. * Jeam Haroldo Oliveira Barbosa 1 , Antonio Carlos Santos 2 , Carlos Ernesto Garrido Salmon 3 Radiol Bras. 2015 Mar/Abr;48(2):93-100  ... 
doi:10.1590/0100-3984.2014.0010 pmid:25987750 pmcid:PMC4433298 fatcat:csvcbdobujdxbjx7cbjk3jwqya

Técnicas quantitativas de imagens por ressonância magnética

Gabriela Castellano, Carlos Ernesto Garrido Salmon
2019 Revista Brasileira de Física Médica  
Técnicas quantitativas de imagem são aquelas que permitem a mensuração de variáveis físicas ou químicas, passíveis de serem comparadas entre diferentes regiões anatômicas e indivíduos. Embora a maioria das técnicas baseadas em ressonância magnética mais utilizadas na clínica não sejam quantitativas, existem várias técnicas baseadas neste fenômeno que o são. O objetivo desta revisão é fornecer uma breve descrição de algumas das principais técnicas quantitativas de imagens baseadas em ressonância
more » ... magnética, assim como de suas aplicações. As técnicas descritas são: relaxometria, imagens ponderadas por difusão e imagens do tensor de difusão, imagens de susceptibilidade magnética, espectroscopia e imagens espectroscópicas.
doi:10.29384/rbfm.2019.v13.n1.p57-65 fatcat:nsglsyhicjegzlrulf5biovz3i

Quantitative MRI data in Multiple Sclerosis patients: a pattern recognition study

Rodrigo Antonio Pessini, Antonio Carlos dos Santos, Carlos Ernesto Garrido Salmon
2018 Research on Biomedical Engineering  
Antonio Carlos da Silva Senra Filho for his useful suggestions and comments.  ...  Eng. 2018 June; 34(2): 138-146 145/146 Pessini RA,Santos AC, Salmon CEG Res. Biomed. Eng. 2018 June; 34(2): 138-146  ... 
doi:10.1590/2446-4740.07117 fatcat:euiytqxykbd5dposuyoxmafcd4

Enhancing quality in Diffusion Tensor Imaging with anisotropic anomalous diffusion filter

Antonio Carlos da Silva Senra Filho, Carlos Ernesto Garrido Salmon, Antonio Carlos dos Santos, Luiz Otávio Murta Junior
2017 Research on Biomedical Engineering  
Diffusion tensor imaging (DTI) is an important medical imaging modality that has been useful to the study of microstructural changes in neurological diseases. However, the image noise level is a major practical limitation, in which one simple solution could be the average signal from a sequential acquisition. Nevertheless, this approach is time-consuming and is not often applied in the clinical routine. In this study, we aim to evaluate the anisotropic anomalous diffusion (AAD) filter in order
more » ... o improve the general image quality of DTI. Methods: A group of 20 healthy subjects with DTI data acquired (3T MR scanner) with different numbers of averages (N=1,2,4,6,8, and 16), where they were submitted to 2-D AAD and conventional anisotropic diffusion filters. The Relative Mean Error (RME), Structural Similarity Index (SSIM), Coefficient of Variation (CV) and tractography reconstruction were evaluated on Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC) maps. Results: The results point to an improvement of up to 30% of CV, RME, and SSIM for the AAD filter, while up to 14% was found for the conventional AD filter (p<0.05). The tractography revealed a better estimative in fiber counting, where the AAD filter resulted in less FA variability. Furthermore, the AAD filter showed a quality improvement similar to a higher average approach, i.e. achieving an image quality equivalent to what was seen in two additional acquisitions. Conclusions: In general, the AAD filter showed robustness in noise attenuation and global image quality improvement even in DTI images with high noise level.
doi:10.1590/2446-4740.02017 fatcat:wfh42wmw7jfpvfcvuc6d4obd74

Evaluation of nuclear magnetic resonance spectroscopy variability

Felipe Rodrigues Barreto, Maria Concepción García Otaduy, Carlos Ernesto Garrido Salmon
2014 Revista Brasileira de Engenharia Biomédica  
Briefly, the software estimates the absolute concentrations using the unsuppressed water signal as an internal reference (Barreto and Salmon, 2010; Graaf, 2007) .  ... 
doi:10.1590/rbeb.2014.023 fatcat:3woqraa7afcfjbqkb4yoszbbp4

Optimization of saddle coils for magnetic resonance imaging

Carlos Ernesto Garrido Salmon, Edson Luiz Géa Vidoto, Mateus José Martins, Alberto Tannús
2006 Brazilian journal of physics  
In Nuclear Magnetic Resonance (NMR) experiments, besides the apparatus designed to acquire the NMR signal, it is necessary to generate a radio frequency electromagnetic field using a device capable to transduce electromagnetic power into a transverse magnetic field. We must generate this transverse homogeneous magnetic field inside the region of interest with minimum power consumption. Many configurations have been proposed for this task, from coils to resonators. For low field intensity (<0.5
more » ... ) and small sample dimensions (<30 cm), the saddle coil configuration has been widely used. In this work we present a simplified method for calculating the magnetic field distribution in these coils considering the current density profile. We propose an optimized saddle configuration as a function of the dimensions of the region of interest, taking into account the uniformity and the sensitivity. In order to evaluate the magnetic field uniformity three quantities have been analyzed: Non-uniformity, peak-to-peak homogeneity and relative uniformity. Some experimental results are presented to validate our calculation.
doi:10.1590/s0103-97332006000100004 fatcat:wvejkxbmyfblbi5h73j7gffdpm

Conectividade Funcional Cerebral utilizando Técnicas de Imagens por Ressonância Magnética

Carlos Ernesto Garrido Salmon, Renata Ferranti Leoni
2019 Revista Brasileira de Física Médica  
Salmon CEG, Leoni RF  ... 
doi:10.29384/rbfm.2019.v13.n1.p66-75 fatcat:wpdg2mqujfeydmajmzdo3fd6cu

Neuro-degeneration profile of Alzheimer's patients: A brain morphometry study

Silvio Ramos Bernardes da Silva Filho, Jeam Haroldo Oliveira Barbosa, Carlo Rondinoni, Antonio Carlos dos Santos, Carlos Ernesto Garrido Salmon, Nereida Kilza da Costa Lima, Eduardo Ferriolli, Júlio César Moriguti
2017 NeuroImage: Clinical  
Alzheimer's disease (AD) is a primary and progressive neurodegenerative disorder, which is marked by cognitive deterioration and memory impairment. Atrophy of hippocampus and other basal brain regions is one of the most predominant structural imaging findings related to AD. Most studies have evaluated the preclinical and initial stages of AD through clinical trials using Magnetic Resonance Imaging. Structural biomarkers for advanced AD stages have not been evaluated yet, being considered only
more » ... pothetically. Objective: To evaluate the brain morphometry of AD patients at all disease stages, identifying the structural neuro-degeneration profile associated with AD severity. Material and methods: AD patients aged 60 years or over at different AD stages were recruited and grouped into three groups following the Clinical Dementia Rating (CDR) score: CDR1 (n = 16), CDR2 (n = 15), CDR3 (n = 13). Age paired healthy volunteers (n = 16) were also recruited (control group). Brain images were acquired on a 3T magnetic resonance scanner using a conventional Gradient eco 3D T1-w sequence without contrast injection. Volumetric quantitative data and cortical thickness were obtained by automatic segmentation using the Freesurfer software. Volume of each brain region was normalized by the whole brain volume in order to minimize age and body size effects. Volume and cortical thickness variations among groups were compared. Results: Atrophy was observed in the hippocampus, amygdala, entorhinal cortex, parahippocampal region, temporal pole and temporal lobe of patients suffering from AD at any stage. Cortical thickness was reduced only in the parahippocampal gyrus at all disease stages. Volume and cortical thickness were correlated with the Mini Mental State Examination (MMSE) score in all studied regions, as well as with CDR and disease duration. Discussion and conclusion: As previously reported, brain regions affected by AD during its initial stages, such as hippocampus, amygdala, entorhinal cortex, and parahippocampal region, were found to be altered even in individuals with severe AD. In addition, individuals, specifically, with CDR 3, have multiple regions with lower volumes than individuals with a CDR 2. These results indicate that rates of atrophy have not plateaued out at CDR 2-3, and in severe patients there are yet neuronal loss and gliosis. These findings can add important information to the more accepted model in the literature that focuses mainly on early stages. Our findings allow a better understanding on the AD pathophysiologic process and follow-up process of drug treatment even at advanced disease stages.
doi:10.1016/j.nicl.2017.04.001 pmid:28459000 pmcid:PMC5397580 fatcat:fhu3pe7k3jhwvjfrl34qscpkey

Applications of the Dixon technique in the evaluation of the musculoskeletal system

Carolina Freitas Lins, Carlos Ernesto Garrido Salmon, Marcello Henrique Nogueira-Barbosa
2020 Radiologia Brasileira  
The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the
more » ... with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.
doi:10.1590/0100-3984.2019.0086 pmid:33583975 pmcid:PMC7869722 fatcat:bysytksklfctxpiskr6i3rkgsa

Dosimetria 3D do Iodo-131: Estudo com Gel MAGIC-f e Código de Simulação Monte Carlo PENELOPE

Marcelo Menna Barreto Schwarcke, Carlos Ernesto Garrido Salmon, Patrícia Nicolucci, Oswaldo Baffa
2019 Revista Brasileira de Física Médica  
tratamento terapêutico utilizando radionuclídeos são resultantes da utilização de modelagem matemática para geometrias de irradiação simples e em geometrias complexas utiliza-se códigos de simulação Monte Carlo  ...  O presente trabalho visa investigar a possível utilização do gel polimérico MAGIC-f como instrumento de validação do código de simulação Monte Carlo PENELOPE aplicado no estudo dosimétrico de tratamento  ...  O arranjo experimental foi simulado utilizando o código de simulação Monte Carlo PENELOPE 2008 8 .  ... 
doi:10.29384/rbfm.2018.v12.n2.p39-43 fatcat:baojalloxzcghlk56ap7mpxmfa

Pattern recognition of abscesses and brain tumors through MR spectroscopy: Comparison of experimental conditions and radiological findings

Bruno Hebling Vieira, Antonio Carlos dos Santos, Carlos Ernesto Garrido Salmon
2017 Research on Biomedical Engineering  
The interpretation of brain tumors and abscesses MR spectra is complex and subjective. In clinical practice, different experimental conditions such as field strength or echo time (TE) reveal different metabolite information. Our study aims to show in which scenarios magnetic resonance spectroscopy can differentiate among brain tumors, normal tissue and abscesses using classification algorithms. Methods: Pairwise classification between abscesses, brain tumor classes, and healthy subjects tissue
more » ... pectra was performed, also the multiclass classification between meningiomas, grade I-II-III gliomas, and glioblastomas and metastases, in 1.5T short TE (n = 195), 1.5T long TE (n = 231) and 3.0T long TE (n = 59) point resolved spectroscopy setups, using LCModel metabolite concentration as input to classifiers. Results: Areas under the curve of the Receiver Operating Characteristic above 0.9 were obtained for the classification between abscesses and all classes except glioblastomas, reaching 0.947 when classifying against metastases, grade I-II gliomas and glioblastomas (0.980), meningiomas and glioblastomas (0.956), grade I-II gliomas and metastases (0.989), meningiomas and metastases (0.990), and between healthy tissue and all other classes in both conditions except for anaplastic astrocytomas in short TE 1.5T setup. When the multiclass classification agrees with radiological diagnosis the accuracy reaches 96.8% for short TE and 98.9% for long TE. Conclusions: The results in the three conditions were similar, highlighting comparable quality, robust quantification and good regularization and flexibility in either algorithm. Multiclass classification provides useful information to the radiologist. These findings show the potential of the development of decision support systems as well as tools for the accompaniment of treatments.
doi:10.1590/2446-4740.00617 fatcat:kow5r237ebaalooo5aymnbjnby

Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL

Carlos Ernesto Garrido Salmon, Diógenes de Sousa Neto, Marcel Tabak, Antonio José da Costa Filho
2007 Química Nova  
Salmon pela bolsa de pós-doutorado.  ... 
doi:10.1590/s0100-40422007000500036 fatcat:a2iqfey2zvbixpt5pb7v7rvja4

Histological correlates of hippocampal magnetization transfer images in drug-resistant temporal lobe epilepsy patients [article]

Jose Eduardo Peixoto-Santos, Tonicarlo Rodrigues Velasco, Carlos Gilberto Carlotti, Joao Alberto Assirati, Gustavo Henrique de Souza e Rezende, Katja Kobow, Roland Coras, Ingmar Blumcke, Carlos Ernesto Garrido Salmon, Antonio Carlos dos Santos, Joao Pereira Leite
2020 medRxiv   pre-print
Temporal lobe epilepsy patients (TLE) often present with hippocampal atrophy, increased T2 relaxation, and reduced magnetization transfer ratio (MTR) in magnetic resonance images (MRI). The histological correlates of the reduced MTR are so far unknown. Since MTR is dependent on the tissue macromolecules, our aim was to evaluate the correlations between cellular populations, extracellular matrix molecules and the MTR in TLE patients. Patients with TLE (n=27) and voluntaries (=20) were scanned in
more » ... a 3 Tesla MRI scanner, and MTR images were calculated from 3DT1 sequences with magnetization pulse on resonance. Immunohistochemistry for neurons, reactive astrocytes, activated microglia, and extracellular matrix chondroitin sulfate were performed in formalin fixed, paraffin embedded tissues of TLE and autopsy controls (n=10). Results were considered significant at p<0.05. Compared to the respective controls, TLE patients had reduced hippocampal MTR, increased reactive astrocytes and activated microglia, increased extracellular chondroitin sulfate, and reduced neuron density, compares to controls. MTR correlated positively with neuron density in CA3 and with chondroitin sulfate in CA3 and CA1. Multiple linear regressions reinforced the correlations between chondroitin sulfate and MTR. Our data indicate that extracellular matrix molecules are the most significant histological correlates of magnetization transfer ratio in the hippocampus of TLE patients.
doi:10.1101/2020.07.10.20150953 fatcat:sxkmoghyz5dfjnmujmtyos2uh4

Relationship of spinal alignment with muscular volume and fat infiltration of lumbar trunk muscles

Rafael Menezes-Reis, Gustavo Perazzoli Bonugli, Carlos Ernesto Garrido Salmon, Debora Mazoroski, Carlos Fernando Pereira da Silva Herrero, Marcello Henrique Nogueira-Barbosa, Robert Daniel Blank
2018 PLoS ONE  
Fat infiltration and atrophy of lumbar muscles are related to spinal degenerative conditions and may cause functional deficits. Spinal alignment exerts biomechanical influence on lumbar intervertebral discs and joints. Our objective was to evaluate if spinopelvic parameters correlate with the lumbar muscle volume and fat infiltration. This is an observational, prospective and cross-sectional study. Ninety-three asymptomatic adult aged 20-40 years were included. Lumbar lordosis (LL), thoracic
more » ... hosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracolumbar alignment (TL), sagittal vertical axis (SVA), C2-pelvic angle (CPA), spinosacral angle (SSA), lack of lordosis (PI-LL), L1S1 and T1S1 length were measured on panoramic spine radiographs. Lumbar axial T1-weighted and In-and Out-Phase images were obtained on 1.5T MRI scanner and were used to extract the muscle volumes and fat fractions of multifidus, erector spinae, and psoas. All muscle volumes were higher in men than women (p<0.05). The fat fraction was higher in the multifidus and erector spinae in women (p<0.05). Multifidus volume was weakly correlated with PT (R = 0.22), PI (R = 0.22), LL (R = 0.34) and CPA (R = 0.29). Erectors spinae volume were correlated with CPA (R = 0.21). Psoas volume correlated with TK (R = 0.21), TL (R = 0.27) and SVA (R = -0.23). The lumbar muscle volumes showed a moderated correlation with T1S1 length (R = 0.55 to 0.62). Spinopelvic parameters showed correlation with lumbar muscle volumes but not with muscle fat infiltration on asymptomatic young adults.
doi:10.1371/journal.pone.0200198 pmid:29975763 pmcid:PMC6033454 fatcat:fa7ovypxbnehndrvn7nk32bgue

Does a small size needle puncture cause intervertebral disc changes?

Ana Carolina Issy, Vitor Castania, Joao Walter Silveira, Marcello Henrique Nogueira-Barbosa, Carlos Ernesto Garrido Salmon, Elaine Del-Bel, Helton Luis Aparecido Defino
2015 Acta Cirurgica Brasileira  
PURPOSE: Small size needles have been regularly used for intradiscal injection of innocuous/potential therapeutic compounds in experimental conditions, but also in clinic procedures, such as discography. Our aim was to investigate if a 30-gauge needle could trigger observable changes on intact intervertebral discs. We compared these effects to those induced by a large size needle (21-gauge), a well-known intervertebral disc degenerative model based on needle puncture. METHODS: Coccygeal
more » ... tebral discs (Co8-9) of adult male Wistar rats were punctured with a 21-gauge needle, while the coccygeal levels Co7-8 and Co9-10 remained intact. The 30-gauge needle was used to inject a safe volume of saline (2 µl) on both intact (Co9-10) and punctured (Co8-9) discs. MRI and histological score were performed at 2, 15 and 42 days after procedure. RESULTS: MRI analyses revealed significant reduction on signal intensity of 21-gauge punctured discs. Intact discs which received a saline injection through a 30-gauge needle also revealed significant alterations in the MRI signal when compared with control discs. No histological changes were observed in the intact saline injected discs at any time analyzed. CONCLUSION: Since significant intervertebral image changes were observed with a 30-gauge needle, cautious interpretation of the pharmacological inoculation findings is required.
doi:10.1590/s0102-865020150080000009 pmid:26352338 fatcat:vvw6v7fsxjcwli6s76cikehgwe
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