Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Neuroimage Clin ; 39: 103489, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37611372

RESUMO

BACKGROUND AND PURPOSE: An impaired neurovascular coupling has been described as a possible player in neurodegeneration and cognitive decline. Migraine is a recurrent and incapacitating disorder that starts early in life and has shown neurovascular coupling abnormalities. Despite its high prevalence, the physiology and underlying mechanisms are poorly understood. In this context, new biomarkers from magnetic resonance imaging (MRI) are needed to bring new knowledge into the field. The aim of this study was to determine the vein density from Susceptibility-Weighted Imaging (SWI) MRI, in subjects with migraine and healthy controls; and to assess whether it relates to Resting-State functional MRI (RS-fMRI). MATERIALS AND METHODS: The cohort included 30 healthy controls and 70 subjects with migraine (26 episodic, 44 chronic) who underwent a brain 3.0 T MRI. Clinical characteristics were also collected. Maps of density of veins were generated based on a Mamdani Fuzzy-Type Rule-Based System from the SWI MRI. Mean values of vein density were obtained in grey (GM) and white matter (WM) Freesurfer lobar parcellations. The Amplitude of Low-Frequency Fluctuations (ALFF) image was calculated for the RS-fMRI, and the mean values over the parcellated GM lobes were estimated. Differences between groups were assessed through and analysis of variance (age, sex, education and anxiety as covariates; p < 0.05), followed by post-hoc comparisons. Associations were run between clinical and MRI-derived variables. RESULTS: When comparing the density of veins in GM, no differences between groups were found, neither associations with clinical variables. The density of veins was significantly higher in the WM of the occipital lobe for subjects with chronic migraine compared to controls (30%, p < 0.05). WM vein density in either frontal, temporal or cingulate regions was associated with clinical variables such as headache days, disability scores, and cognitive impairment (r between 0.25 and 0.41; p < 0.05). Mean values of ALFF did not differ significantly between controls and subjects with migraine. Strong significant associations between vein density and ALFF measures were obtained in most GM lobes for healthy subjects (r between 0.50 and 0.67; p < 0.05), instead, vein density in WM was significantly associated with ALFF for subjects with migraine (r between 0.32 and 0.58; p < 0.05). CONCLUSIONS: Results point towards an increase in vein density in subjects with migraine, when compared to healthy controls. In addition, the association between GM vein density and ALFF found in healthy subjects was lost in migraine. Taken together, these results support the idea of abnormalities in the neurovascular coupling in migraine. Quantitative SWI MRI indicators in migraine might be an interesting target that may contribute to its comprehension.


Assuntos
Transtornos de Enxaqueca , Acoplamento Neurovascular , Humanos , Transtornos de Enxaqueca/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Ansiedade , Imageamento por Ressonância Magnética
2.
AJNR Am J Neuroradiol ; 44(7): 867-872, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37290816

RESUMO

BACKGROUND AND PURPOSE: As in the brain reserve concept, a larger cervical canal area may also protect against disability. In this context, a semiautomated pipeline has been developed to obtain quantitative estimations of the cervical canal area. The aim of the study was to validate the pipeline, to evaluate the consistency of the cervical canal area measurements during a 1-year period, and to compare cervical canal area estimations obtained from brain and cervical MRI acquisitions. MATERIALS AND METHODS: Eight healthy controls and 18 patients with MS underwent baseline and follow-up 3T brain and cervical spine sagittal 3D MPRAGE. The cervical canal area was measured in all acquisitions, and estimations obtained with the proposed pipeline were compared with manual segmentations performed by 1 evaluator using the Dice similarity coefficient. The cervical canal area estimations obtained on baseline and follow-up T1WI were compared; brain and cervical cord acquisitions were also compared using the individual and average intraclass correlation coefficients. RESULTS: The agreement between the manual cervical canal area masks and the masks provided by the proposed pipeline was excellent, with a mean Dice similarity coefficient mean of 0.90 (range, 0.73-0.97). The cervical canal area estimations obtained from baseline and follow-up scans showed a good level of concordance (intraclass correlation coefficient = 0.76; 95% CI, 0.44-0.88); estimations obtained from brain and cervical MRIs also had good agreement (intraclass correlation coefficient = 0.77; 95% CI, 0.45-0.90). CONCLUSIONS: The proposed pipeline is a reliable tool to estimate the cervical canal area. The cervical canal area is a stable measure across time; moreover, when cervical sequences are not available, the cervical canal area could be estimated using brain T1WI.


Assuntos
Medula Cervical , Traumatismos da Medula Espinal , Humanos , Medula Espinal , Imageamento por Ressonância Magnética , Medula Cervical/diagnóstico por imagem , Algoritmos , Traumatismos da Medula Espinal/diagnóstico por imagem , Canal Medular
3.
AJNR Am J Neuroradiol ; 44(5): 569-573, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37080719

RESUMO

BACKGROUND AND PURPOSE: In MS, it is common to acquire brain and spinal cord MR imaging sequences separately to assess the extent of the disease. The goal of this study was to see how replacing the traditional brain T1-weighted images (brain-T1) with an acquisition that included both the brain and the cervical spinal cord (cns-T1) affected brain- and spinal cord-derived measures. MATERIALS AND METHODS: Thirty-six healthy controls (HC) and 42 patients with MS were included. Of those, 18 HC and 35 patients with MS had baseline and follow-up at 1 year acquired on a 3T magnet. Two 3D T1-weighted images (brain-T1 and cns-T1) were acquired at each time point. Regional cortical thickness and volumes were determined with FastSurfer, and the percentage brain volume change per year was obtained with SIENA. The spinal cord area was estimated with the Spinal Cord Toolbox. Intraclass correlation coefficients (ICC) were calculated to check for consistency of measures obtained from brain-T1 and cns-T1. RESULTS: Cortical thickness measures showed an ICC >0.75 in 94% of regions in healthy controls and 80% in patients with MS. Estimated regional volumes had an ICC >0.88, and the percentage brain volume change had an ICC >0.79 for both groups. The spinal cord area measures had an ICC of 0.68 in healthy controls and 0.92 in patients with MS. CONCLUSIONS: Brain measurements obtained from 3D cns-T1 are highly equivalent to those obtained from a brain-T1, suggesting that it could be feasible to replace the brain-T1 with cns-T1.


Assuntos
Medula Cervical , Esclerose Múltipla , Humanos , Medula Espinal/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem
4.
Int J Surg ; 97: 106168, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34785344

RESUMO

BACKGROUND AND AIMS: Emergency General Surgery (EGS) conditions account for millions of deaths worldwide, yet it is practiced without benchmarking-based quality improvement programs. The aim of this observational, prospective, multicenter, nationwide study was to determine the best benchmark cutoff points in EGS, as a reference to guide improvement measures. METHODS: Over a 6-month period, 38 centers (5% of all public hospitals) attending EGS patients on a 24-h, 7-days a week basis, enrolled consecutive patients requiring an emergent/urgent surgical procedure. Patients were stratified into cohorts of low (i.e., expected morbidity risk <33%), middle and high risk using the novel m-LUCENTUM calculator. RESULTS: A total of 7258 patients were included; age (mean ± SD) was 51.1 ± 21.5 years, 43.2% were female. Benchmark cutoffs in the low-risk cohort (5639 patients, 77.7% of total) were: use of laparoscopy ≥40.9%, length of hospital stays ≤3 days, any complication within 30 days ≤ 17.7%, and 30-day mortality ≤1.1%. The variables with the greatest impact were septicemia on length of hospital stay (21 days; adjusted beta coefficient 16.8; 95% CI: 15.3 to 18.3; P < .001), and respiratory failure on mortality (risk-adjusted population attributable fraction 44.6%, 95% CI 29.6 to 59.6, P < .001). Use of laparoscopy (odds ratio 0.764, 95% CI 0.678 to 0.861; P < .001), and intraoperative blood loss (101-500 mL: odds ratio 2.699, 95% CI 2.152 to 3.380; P < .001; and 500-1000 mL: odds ratio 2.875, 95% CI 1.403 to 5.858; P = .013) were associated with increased morbidity. CONCLUSIONS: This study offers, for the first time, clinically-based benchmark values in EGS and identifies measures for improvement.


Assuntos
Cirurgia Geral , Procedimentos Cirúrgicos Operatórios , Adulto , Idoso , Benchmarking , Estudos de Coortes , Emergências , Feminino , Mortalidade Hospitalar , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Prospectivos , Melhoria de Qualidade , Estudos Retrospectivos
6.
Eur J Neurol ; 27(11): 2225-2232, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32602573

RESUMO

BACKGROUND AND PURPOSE: Both optical coherence tomography (OCT) and magnetic resonance imaging (MRI) volumetric measures have been postulated as potential biomarkers of multiple sclerosis (MS)-related disability. The aim of the study was to investigate the association between OCT and brain volume and spinal cord area (SCA) parameters in patients with relapsing MS and to assess their independent associations with disability. METHODS: This was a cross-sectional analysis of 90 patients with MS who underwent OCT and MRI examination. Values of peripapillary retinal nerve fibre layer (pRNFL), ganglion cell/inner plexiform layer (GCIPL) and inner nuclear layer of eyes without previous optic neuritis were obtained. SCA and brain parenchymal fraction (BPF), grey and white matter fractions were obtained. Multivariable regression analyses were conducted with disability as dependent variable. RESULTS: Lower pRNFL thickness and lower GCIPL volume as well as lower BPF, grey matter fraction and SCA were associated with a longer disease duration and a higher Expanded Disability Status Scale score. Lower pRNFL thickness and GCIPL volumes were associated with lower BPF and SCA. In the multivariable logistic regression analyses, pRNFL thickness and GCIPL volume outperformed MRI in predicting disability. CONCLUSIONS: The OCT measures correlate with brain and spinal cord atrophy and appear more closely associated with disability than MRI volumetric measures.


Assuntos
Esclerose Múltipla , Tomografia de Coerência Óptica , Atrofia , Encéfalo/diagnóstico por imagem , Estudos Transversais , Humanos , Esclerose Múltipla/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem
7.
AJNR Am J Neuroradiol ; 41(6): 1001-1008, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32439639

RESUMO

BACKGROUND AND PURPOSE: Previous studies have suggested that the central vein sign and iron rims are specific features of MS lesions. Using 3T SWI, we aimed to compare the frequency of lesions with central veins and iron rims in patients with clinically isolated syndrome and MS-mimicking disorders and test their diagnostic value in predicting conversion from clinically isolated syndrome to MS. MATERIALS AND METHODS: For each patient, we calculated the number of brain lesions with central veins and iron rims. We then identified a simple rule involving an absolute number of lesions with central veins and iron rims to predict conversion from clinically isolated syndrome to MS. Additionally, we tested the diagnostic performance of central veins and iron rims when combined with evidence of dissemination in space. RESULTS: We included 112 patients with clinically isolated syndrome and 35 patients with MS-mimicking conditions. At follow-up, 94 patients with clinically isolated syndrome developed MS according to the 2017 McDonald criteria. Patients with clinically isolated syndrome had a median of 2 central veins (range, 0-19), while the non-MS group had a median of 1 central vein (range, 0-6). Fifty-six percent of patients who developed MS had ≥1 iron rim, and none of the patients without MS had iron rims. The sensitivity and specificity of finding ≥3 central veins and/or ≥1 iron rim were 70% and 86%, respectively. In combination with evidence of dissemination in space, the 2 imaging markers had higher specificity than dissemination in space and positive findings of oligoclonal bands currently used to support the diagnosis of MS. CONCLUSIONS: A single 3T SWI scan offers valuable diagnostic information, which has the potential to prevent MS misdiagnosis.


Assuntos
Encéfalo/diagnóstico por imagem , Doenças Desmielinizantes/diagnóstico por imagem , Esclerose Múltipla/diagnóstico por imagem , Neuroimagem/métodos , Adulto , Idoso , Encéfalo/patologia , Doenças Desmielinizantes/patologia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/patologia , Sensibilidade e Especificidade , Adulto Jovem
8.
AJNR Am J Neuroradiol ; 41(3): 461-463, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32139431

RESUMO

The study aim was to compare the ratio of T1WI to T2WI signal intensity (T1/T2) with magnetization transfer ratio, a marker of myelin integrity, in patients with multiple sclerosis. A moderate correlation (r = 0.50, P = .034) was found between the magnetization transfer ratio and T1/T2 in normal-appearing gray matter, and a strong correlation for normal-appearing white matter (r = 0.63, P = .005) and lesions (r = 0.70, P = .001). Results suggest that besides myelin integrity, other factors may be playing a role in T1/T2 measures.


Assuntos
Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Esclerose Múltipla Recidivante-Remitente/patologia , Bainha de Mielina/patologia , Substância Branca/patologia
9.
AJNR Am J Neuroradiol ; 39(2): 399-404, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29284602

RESUMO

BACKGROUND AND PURPOSE: Cervical cord atrophy has been associated with clinical disability in multiple sclerosis and is proposed as an outcome measure of neurodegeneration. The aim of this study was to quantify the development of cervical cord atrophy and to evaluate its association with disability progression in patients with primary-progressive multiple sclerosis. MATERIALS AND METHODS: Thirty-one patients with primary-progressive multiple sclerosis underwent 1.5T brain and spinal cord MR imaging at baseline and 6-7 years later. The cervical spinal cord from C1 to C5 was segmented to evaluate the normalized overall cross-sectional area and the cross-sectional area of C2-C3, C3-C4, and C4-C5. The annualized rates of normalized cross-sectional area loss were also evaluated. To estimate clinical progression, we determined the Expanded Disability Status Scale score at baseline and at 2 and 14 years after baseline to compute the normalized area under the curve of the Expanded Disability Status Scale and the Expanded Disability Status Scale changes from baseline to the follow-up time points. Associations between the cord cross-sectional area and brain MR imaging and clinical measures were also investigated. Finally, the value of all these measures for predicting long-term disability was evaluated. RESULTS: Some normalized cross-sectional area measurements showed moderate correlations with the normalized area under the curve of the Expanded Disability Status Scale, ranging from -0.439 to -0.359 (P < .05). Moreover, the annualized rate of the normalized mean cross-sectional area loss and the baseline Expanded Disability Status Scale were independent predictors of long-term disability progression. CONCLUSIONS: These data indicate that development of cervical cord atrophy is associated with progression of disability and is predictive of this event in patients with primary-progressive MS.


Assuntos
Medula Cervical/patologia , Avaliação da Deficiência , Esclerose Múltipla Crônica Progressiva/patologia , Adulto , Idoso , Atrofia/patologia , Medula Cervical/diagnóstico por imagem , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Crônica Progressiva/diagnóstico por imagem
10.
Waste Manag ; 26(1): 71-81, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-15946838

RESUMO

The application of biosolids such as sewage sludge is a concern, because of the potential release of toxic metals after decomposition of the organic matter. The effect of application of sewage sludge (Sw) and compost (C) to the soil (S) on the Cu and Cd sorption, distribution and the quality of the dissolved organic matter (DOM) in the soil, was investigated under controlled conditions. Visible spectrophotometry, infrared spectroscopy, sorption isotherms (simple and competitive sorption systems), and sequential extraction methods were used. The E4/E6 (lambda at 465 and 665 nm) ratio and the infrared spectra (IR) of DOM showed an aromatic behaviour in compost-soil (C-S); in contrast sewage sludge-soil (Sw-S) showed an aliphatic behaviour. Application of either Sw or C increased the Cu sorption capacity of soil. The Cd sorption decreased only in soil with a competitive metal system. The availability of Cu was low due to its occurrence in the acid soluble fraction (F3). The Cu concentration varied in accordance with the amounts of Cu added. The highest Cd concentration was found in the exchangeable fraction (F2). The Sw and C applications did not increase the Cd availability in the soil.


Assuntos
Cádmio/química , Cobre/química , Esgotos , Poluentes do Solo , Solo , Adsorção , Disponibilidade Biológica , Fracionamento Químico , Fertilizantes , Concentração de Íons de Hidrogênio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...