Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
J Clin Pathol ; 58(9): 994-5, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16126887

RESUMO

This report describes the case of a 54 year old woman with very severe aplastic anaemia who was treated with antilymphocyte globulin (ALG) and developed Guillain Barré syndrome (GBS). No antecedent infective aetiology was identified. Although there are numerous reports of autoimmune disease after treatment with ALG in aplastic anaemia, and GBS after immunosuppressive treatment, there are none reporting GBS after the use of ALG for severe aplastic anaemia. The occurrence of autoimmune disease after immunosuppressive treatment, in particular ALG, is discussed, together with the possible mechanisms that result from T cell depression.


Assuntos
Anemia Aplástica/terapia , Soro Antilinfocitário/efeitos adversos , Síndrome de Guillain-Barré/induzido quimicamente , Doenças Autoimunes/induzido quimicamente , Feminino , Humanos , Imunossupressores/efeitos adversos , Pessoa de Meia-Idade
2.
Neurology ; 53(5 Suppl 3): S33-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10496209

RESUMO

Magnetization transfer (MT) techniques may be applied to magnetic resonance imaging (MRI) to evaluate the inherent relaxation properties of heterogeneous tissues. In addition to providing a unique contrast mechanism for the purpose of qualitative imaging, the MT effect may be quantified by various means to provide useful data that relate either to the pathological or associated clinical features of multiple sclerosis (MS) and other neurological disorders. The variable and relatively unpredictable course of neurological disorders such as MS often necessitates the study of large patient cohorts in multiple MRI centers to define either the natural history of the disease or its modification by potential therapies. For multicenter studies, precision (reproducibility, or lack of random error) and accuracy (closeness to the truth, or lack of systematic error) are important requirements for the acquisition of standardized and comparable data. For serial studies, quality assurance is important to determine pathological change from fluctuation in scanner performance. This review addresses how MT imaging techniques may be utilized to provide standardized and clinically relevant measures.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética , Esclerose Múltipla/patologia , Humanos , Estudos Multicêntricos como Assunto , Padrões de Referência
3.
Neurology ; 51(3): 758-64, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9748023

RESUMO

OBJECTIVE: To explore the temporal relation of demyelination and blood-brain barrier breakdown during new lesion formation. BACKGROUND: Conventional MRI appears sensitive for detecting changes due to MS, but may be limited by poor pathologic specificity. By indirectly assessing protons bound to rigid macromolecules, magnetization transfer (MT) imaging may provide information relating to tissue structure and, by inference, myelin integrity. METHODS: Gadolinium contrast-enhanced MRI and MT imaging were performed at weekly intervals for 3 months in three patients with MS. For each enhancing lesion, the largest corresponding area of proton density hyperintensity seen during the study was outlined and magnetization transfer ratio (MTR) calculated at each time point from coregistered calculated MTR images. Lesions greater than 20 mm2, not affected by partial volume effects, and first enhancing after the baseline study were analyzed. Two-dimensional registration software allowed accurate evaluation of MTR in regions both before and after the initial appearance of MS lesions. RESULTS: Mean lesion MTR decreased significantly during the first week of enhancement (29.6 percent units [pu] immediately pre-enhancement versus 28.2 pu at first documented stage of enhancement). No significant MTR reduction was noted before this. CONCLUSION: The lack of observable change in MTR before the first detectable gadolinium enhancement within MS lesions suggests that blood-brain barrier disruption is closely related to, but not preceded by, demyelination.


Assuntos
Barreira Hematoencefálica , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/diagnóstico , Bainha de Mielina/patologia , Adulto , Feminino , Gadolínio , Humanos
4.
J Neurol ; 248(3): 215-24, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11355156

RESUMO

By detecting focal blood-brain barrier (BBB) breakdown, gadolinium (Gd-DTPA) contrast-enhanced T1-weighted magnetic resonance imaging (MRI) allows assessment of inflammatory activity in multiple sclerosis (MS) and provides a sensitive means of monitoring immunomodulatory therapies in exploratory trials. Serial monthly studies were performed in eight relapsing-remitting and eight secondary progressive patients to assess new and more sensitive techniques for enhanced MRI. Brain and spine imaging was carried out at 1.5-T on two occasions 24-72 h apart using a conventional imaging protocol with T1-weighted MRI at single-dose (0.1 mmol/kg) Gd-DTPA and a potentially more sensitive "modified" protocol with T1-weighted MRI at triple-dose (0.3 mmol/kg) Gd-DTPA (with addition of delay and magnetisation transfer presaturation for brain imaging). For each MRI protocol the total numbers of enhancing lesions (97 paired studies) and new enhancing lesions (81 paired studies) were assessed. The total number of enhancing lesions seen was 347/75 on conventional brain/cord MRI respectively, and 754/123 on modified brain/cord MRI. The respective numbers of new enhancing lesions were 168/40 on conventional and 276/71 on modified scans. Smaller increases were seen in the proportion of active scans using the modified protocol. Sample size calculations showed no reduction in sample sizes required for a parallel group study but a reduced sample size for crossover studies using the modified protocol; the addition of cord to brain imaging did not improve power for either trial design. A combined modified brain and cord imaging protocol markedly improves the detection of areas of focal BBB leakage in MS and may be useful in selected natural history studies. The modified brain protocol reduces sample size requirements for crossover studies but not necessarily for parallel design trials.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla Crônica Progressiva/patologia , Esclerose Múltipla Recidivante-Remitente/patologia , Medula Espinal/patologia , Adulto , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/fisiologia , Ensaios Clínicos como Assunto/métodos , Meios de Contraste/administração & dosagem , Estudos Cross-Over , Gadolínio DTPA , Humanos , Pessoa de Meia-Idade , Método Simples-Cego , Estatísticas não Paramétricas
5.
J Neurol ; 250(1): 67-74, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12527995

RESUMO

BACKGROUND: In 10-15 % of patients with multiple sclerosis (MS), the clinical course is characterized by slow progression in disability without relapses (primary progressive (PP) MS). The mechanism of disability in this form of MS is poorly understood. Using magnetization transfer ratio (MTR) imaging, we investigated normal appearing white matter (NAWM) and normal appearing grey matter (NAGM) in PPMS and explored the relationship of MTR measures with disability. METHODS: Thirty patients with PPMS and 30 age matched controls had spin echo based MTR imaging to study lesions and normal appearing tissues. The brain was segmented into NAWM and NAGM using SPM99 with lesions segmented using a semiautomated local thresholding technique. A 75% probability threshold for classification of NAWM and NAGM was used to diminish partial volume effects. From normalized histograms of MTR intensity values, six MTR parameters were measured. Mean lesion MTR and T2 lesion volume were also measured. Disability was assessed using Kurtzke's expanded disability status scale (EDSS). RESULTS: Compared with controls, patients exhibited a significant reduction in mean NAWM (p = 0.001) and NAGM (p = 0.004) MTR. Spearman's rank correlation of EDSS with the six MTR parameters in NAWM and NAGM, mean lesion MTR, and T2 lesion volume, was only significant with mean NAGM MTR (r = -0.41, p = 0.02), the 25th percentile of NAGM MTR intensity (r = -0.37, p = 0.05), and T2 lesion volume (r = 0.39, p = 0.04). Multiple regression analysis of the relationship between EDSS and 4 MR parameters representing each tissue type (mean NAWM MTR, mean NAGM MTR, mean lesion MTR, T2 lesion volume) showed that the association of EDSS with mean NAGM MTR remained significant. CONCLUSIONS: There appear to be significant abnormalities in the NAGM in PP MS. Further investigation of the pathological basis and functional significance of grey matter abnormality in PPMS is warranted.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética , Esclerose Múltipla Crônica Progressiva/patologia , Adulto , Avaliação da Deficiência , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Análise de Regressão
6.
J Neurol Sci ; 187(1-2): 35-9, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11440742

RESUMO

In multiple sclerosis (MS), hypointense lesions on T1-weighted magnetic resonance imaging are thought to represent areas of tissue disruption and axonal loss. In previous studies of MS patients, infratentorial T1 hypointense lesions were found to be rare. In MS patients selected to have chronic cerebellar ataxia, we have determined the extent of infratentorial T1 hypointense lesions and their relationship with disability. We recruited nine patients with chronic cerebellar ataxia due to MS. An expanded disability status scale (EDSS) assessment was performed on each. The patients' brains were then imaged with axial-oblique dual-echo fast spin-echo and contrast-enhanced T1-weighted conventional spin-echo sequences. The number and total volume of infratentorial high-signal lesions on T2-weighted images and infratentorial hypointense lesions on T1-weighted images were calculated by a blinded observer using a computer-assisted contouring technique. A total of 96 infratentorial high-signal lesions were present, of which 62 (64.6%) appeared isointense and 34 (35.4%) hypointense with respect to the surrounding brain substance on the T1-weighted images. There was a median of 3 (range 0-10) and median volume of 0.43 ml (range 0-0.85 ml) infratentorial T1 hypointense lesions per patient. The EDSS score correlated with both the number (r=0.68, p=0.043) and the volume per patient (r=0.89, p=0.001) of infratentorial T1 hypointense but not T2 high-signal lesions. Infratentorial T1 hypointense lesions are often seen in patients with MS and chronic cerebellar ataxia. They may play a significant role in the disability suffered by these patients.


Assuntos
Ataxia Cerebelar/etiologia , Ataxia Cerebelar/patologia , Cerebelo/patologia , Cerebelo/fisiopatologia , Esclerose Múltipla/complicações , Esclerose Múltipla/patologia , Adolescente , Adulto , Tronco Encefálico/patologia , Tronco Encefálico/fisiopatologia , Ataxia Cerebelar/fisiopatologia , Avaliação da Deficiência , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia
7.
J Neurol Sci ; 185(1): 11-7, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11266685

RESUMO

INTRODUCTION: Global magnetisation transfer ration (MTR) histogram analysis in the brain offers a method for evaluating pathological change both as a result of lesions and microscopic changes in normal appearing tissues. METHODS: 39 controls and 83 MS patients (46 primary progressive, 11 benign, 10 relapsing-remitting, 16 secondary progressive) were studied to explore the relationship of six conventional MTR histogram parameters with MS clinical subgroups and disability. Principal component (PC) analysis, which makes use of all the histogram data, was also used to examine the relationship between the MTR histogram and disability. RESULTS: When primary progressive patients were compared to controls, there were abnormalities of average MTR, and MTR at the 25th, 50th and 75th percentile. Disabled relapsing onset patients exhibited abnormalities in the same four parameters. Benign and nondisabled relapsing onset patients exhibited no significant abnormalities. Modest correlations were observed between disability and individual MTR parameters in relapse onset but not primary progressive patients--PC analysis revealed stronger and significant associations with disability in both subgroups. (r=0.40 for primary progressive and r=0.51 for relapsing onset). CONCLUSION: A number of MTR parameters are abnormal in primary progressive MS. MTR abnormalities are seen in disabled patients, whether of relapsing or primary progressive onset. The improved correlation with disability obtained by PC analysis suggests a useful role of this method for following clinically relevant pathological changes depicted in the MTR histogram.


Assuntos
Imageamento por Ressonância Magnética , Esclerose Múltipla Crônica Progressiva/diagnóstico , Esclerose Múltipla Recidivante-Remitente/diagnóstico , Adulto , Estudos de Coortes , Diagnóstico Diferencial , Avaliação da Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
8.
J Neurol Sci ; 145(1): 77-81, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9073032

RESUMO

Nitric oxide and its highly reactive derivative peroxynitrite have been implicated as non-specific inflammatory mediators of neuronal and oligodendrocyte damage and death in multiple sclerosis. In a cross-sectional study we found levels of the nitric oxide metabolites nitrate and nitrite to be raised in the serum of patients with demyelinating disease (65.6 microM (SD 32.9)), acquired immune deficiency syndrome (57.9 microM (SD 34.9)) and inflammatory neurological disease (57.5 microM (SD 31.3)), compared with normal control subjects (32.8 microM (SD 12.2)) and patients with non-inflammatory neurological disease (41.1 microM (SD 12.3), p < 0.001). Nitric oxide metabolites were raised in all clinical subtypes of multiple sclerosis, as well as in clinically isolated syndromes compatible with demyelination, and were not related to progressive disease or disability. This study provides further evidence for a role of nitric oxide in the immunopathogenesis of inflammatory diseases of the central nervous system, including multiple sclerosis.


Assuntos
Esclerose Múltipla/sangue , Nitratos/sangue , Nitritos/sangue , Síndrome da Imunodeficiência Adquirida/sangue , Adulto , Feminino , HIV-1 , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso/sangue
9.
Percept Mot Skills ; 84(3 Pt 1): 908-10, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9172201

RESUMO

A sample of 124 undergraduate students completed the Sexuality Scale and the Sexual Approach Questionnaire developed by Snell. The analysis indicated that those who scored high on the Exchange approach to sexuality (n = 43) scored lower on Sexual Esteem and higher on Sexual Depression and Sexual Preoccupation than those who scored low on Exchange (n = 43). Furthermore, men (n = 49) scored higher on preoccupation with sex than did women (n = 75).


Assuntos
Inventário de Personalidade/estatística & dados numéricos , Comportamento Sexual , Disfunções Sexuais Psicogênicas/psicologia , Adolescente , Adulto , Feminino , Identidade de Gênero , Humanos , Relações Interpessoais , Masculino , Psicometria , Disfunções Sexuais Psicogênicas/diagnóstico , Estudantes/psicologia
10.
Percept Mot Skills ; 80(3 Pt 1): 920-2, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7567412

RESUMO

The purpose of the study was to assess differences in color preferences between the sexes. A sample of 193 retirees were asked to report their favorite colors. The pattern of frequencies for preferred color differed as a function of sex. Blue was chosen as the most preferred color by both sexes. Women preferred black and purple more than men did. Moreover, the men preferred red over pink, whereas the women preferred red and pink equally. The rank order of color preferences for this elderly group were very similar to the findings of Silver, et al. who sampled young adults in 1988.


Assuntos
Envelhecimento/psicologia , Comportamento de Escolha , Percepção de Cores , Identidade de Gênero , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência
11.
Genet Soc Gen Psychol Monogr ; 114(2): 211-55, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3402729

RESUMO

Reaction times (RTs) and net interference measures were obtained for 64 Stroop color-word stimuli from 8 common colors. Subjects were 64 college students, 32 of each sex. The incongruous stimulus was designated as either the ink interpretation different from the word or the word interpretation different from the ink. Consistently large variations within Stroop stimuli and Word x Ink interactions were found. Complex qualitative and quantitative differences were revealed between sexes. Females had faster RTs, but showed no significant superiority in measured net interference. The derived rank orders of net interference between sexes were correlated when using the ink, but not when using the word. Neither word nor ink were related in ranking RTs. For net interference, however, derived RTs were highly related for women using the ink interpretation, but not when using the word; they were unrelated for men using either interpretation. Two interrference types were highly correlated for women, but not for men. An additional experiment with a color-blind group cast an interesting light on the issue. Our Stroop data, rank ordered by sex for each measure, may assist viable theory constructions, including the context-dependent interaction hypothesis.


Assuntos
Atenção , Percepção de Cores , Aprendizagem por Discriminação , Semântica , Adulto , Feminino , Humanos , Masculino , Tempo de Reação , Fatores Sexuais
14.
Mol Ecol Resour ; 8(4): 763-4, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21585885

RESUMO

An interactive fortran program (incor) performs the Paul (1989) procedure for testing the null hypothesis that more than two independent population correlations are equivalent. The program also performs subsequent range tests for comparing all possible pairwise correlations.

15.
MAGMA ; 18(3): 162-9, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16028083

RESUMO

There are currently four problems in characterising small nonuniform lesions or other objects in Magnetic Resonance images where partial volume effects are significant. Object size is over- or under-estimated; boundaries are often not reproducible; mean object value cannot be measured; and fuzzy borders cannot be accommodated. A new measure, Object Strength, is proposed. This is the sum of all abnormal intensities, above a uniform background value. For a uniform object, this is simply the product of the increase in intensity and the size of the object. Biologically, this could be at least as relevant as existing measures of size or mean intensity. We hypothesise that Object Strength will perform better than traditional area measurements in characterising small objects. In a pilot study, the reproducibility of object strength measurements was investigated using MR images of small multiple sclerosis (MS) lesions. In addition, accuracy was investigated using artificial lesions of known volume (0.3-6.2 ml) and realistic appearance. Reproducibility approached that of area measurements (in 33/90 lesion reports the difference between repeats was less than for area measurements). Total lesion volume was accurate to 0.2%. In conclusion, Object Strength has potential for improved characterisation of small lesions and objects in imaging and possibly spectroscopy.


Assuntos
Algoritmos , Artefatos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/diagnóstico , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Ergonomics ; 38(11): 2188-206, 1995 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7498184

RESUMO

Signal words, such as DANGER, WARNING and CAUTION, are commonly used in sign and product label warnings for the purpose of conveying different levels of hazard. Previous research has focused on whether people's perceptions of connoted hazard are consistent with the levels suggested by design standards and guidelines. Most investigations have used college students to evaluate the terms; other populations who may be at greater risk have not been adequately studied. One purpose of the present research was to determine whether young children, the elderly, and non-native English speakers perceive similar connoted hazard levels from the terms as undergraduates and published guidelines. A second purpose was to assess the terms' comprehensibility using various metrics such as missing values (i.e. ratings left blank) and understandability ratings. A third purpose was to develop a list of potential signal words that probably would be understandable to members of special populations. In the first experiment, 298 fourth- to eighth-grade students and 70 undergraduates rated 43 potential signal words on how careful they would be after seeing each term. The undergraduates also rated the terms on strength and understandability. In the second experiment, 98 elders and 135 non-native English speakers rated the same set of terms. The rank ordering of the words was found to be consistent across the participant groups. In general, the younger students gave higher carefulness ratings than the undergraduates. The words that the younger children and the non-native English speakers frequently left blank were given lower understandability ratings. Finally, a short list of terms was derived that 95% or 99% of the youngest students (fourth- and fifth-graders) and 80% of the non-native English speakers understood. Implications of hazard communication are discussed.


Assuntos
Substâncias Perigosas , Rotulagem de Produtos/normas , Adulto , Idoso , Criança , Comunicação , Humanos
17.
Ergonomics ; 38(11): 2207-20, 1995 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7498185

RESUMO

Previous research has examined the connoted hazard of various colour and signal words separately. The purpose of the present research was to examine the interaction of signal words and colours. Two separate experiments examined the influence of colour on perceptions of hazard and on compliance to printed warnings. In experiment 1, a sample of 30 undergraduates rated the perceived hazard of signal words printed in specific hazard colours. Results indicated that the level of hazard varied as a function of the signal word and the colour in which it was presented. Of the colours used, red conveyed the highest level of perceived hazard followed by orange, black, green and blue. More importantly, it was noted that a signal word such as DEADLY connoted less hazard when printed in green than in red ink. Experiment 2 examined the effect of colour on compliance with printed warnings. Sixty-five undergraduates interacted with a pool-water test kit and a two-part adhesive. The warning on each product was factorial for colour (i.e. red, green and black). Behavioural compliance was assessed by indicating if subjects donned protective gloves as directed by the warning. The data indicated that warnings printed in red resulted in a higher proportion of compliant behaviour than green and black combined. Implications for warning design are discussed.


Assuntos
Cor , Comportamento Cooperativo , Substâncias Perigosas , Percepção , Rotulagem de Produtos/métodos , Adulto , Feminino , Humanos , Masculino
18.
Eur Neurol ; 44(4): 222-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11096222

RESUMO

In multiple sclerosis (MS) gadolinium (Gd)-enhanced MRI activity correlates weakly with immunological markers of disease activity. We, therefore, tested the hypothesis that the poor correlation could be partly explained by the temporal profile of Gd enhancement. We measured urinary neopterin:creatinine ratios (neopt.:creat.(urine)) in 5 patients with active MS undergoing weekly Gd-enhanced MRI studies of the brain. The neopt.:creat.(urine) associated with new Gd-enhancing lesions (<8 days) was significantly higher than the ratio not associated with new Gd-enhancing lesions [mean(geometric) neopt.: creat.(urine) = 413 micromol/mol (range = 207-521) vs. 250 micromol/mol (range = 132-492), p = 0.03]. Pro-inflammatory immunological markers, which are probably produced early on in the life cycle of an active MS lesion, should preferably be correlated with newly enhancing lesions (<8 days). Failure to do this may explain the poor and unpredictable correlations between immunological markers and Gd-enhanced MRI activity, which cannot be accurately aged in cross-sectional and serial monthly MRI studies.


Assuntos
Biomarcadores/urina , Encéfalo/patologia , Gadolínio , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/imunologia , Esclerose Múltipla/patologia , Neopterina/urina , Corticosteroides/farmacologia , Adulto , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Creatinina/urina , Progressão da Doença , Feminino , Humanos , Interferon gama/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Esclerose Múltipla/urina , Prevenção Secundária , Fatores de Tempo
19.
Neuroradiology ; 39(4): 243-9, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9144670

RESUMO

Axial fast FLAIR images of the brains of 40 normal volunteers in four age groups between 16 and 55 years were examined and the number and size of areas of increased white-matter signal recorded. Increased signal in the corticospinal tract region was seen at the level of the internal capsule in all subjects, extending up towards the centrum semiovale and down towards the pons for 0.5-5.5 cm (median 2.5 cm). In all cases the IIIrd and IVth ventricles were outlined by a thin line of high signal. Focal areas of high signal (caps) were seen around the frontal and occipital horns in 90% and 77% respectively; 54% of caps were asymmetrical. None of the above features varied with the age or sex of the subject, but the numbers of discrete white matter 'lesions' increased with age. The findings are used to suggest guidelines for the identification of areas of 'normal' high signal to be excluded in quantification of lesions on fast FLAIR images.


Assuntos
Encefalopatias/diagnóstico , Encéfalo/patologia , Aumento da Imagem/instrumentação , Processamento de Imagem Assistida por Computador/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Adolescente , Adulto , Artefatos , Encefalopatias/patologia , Tronco Encefálico/patologia , Córtex Cerebral/patologia , Ventrículos Cerebrais/patologia , Líquido Cefalorraquidiano , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico , Esclerose Múltipla/patologia , Tratos Piramidais/patologia , Valores de Referência , Sensibilidade e Especificidade , Tálamo/patologia
20.
Magn Reson Med ; 46(3): 600-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11550255

RESUMO

Magnetization transfer ratio (MTR) histograms have the potential to characterize subtle diffuse changes in multiple sclerosis (MS) and other white matter disease. A new method is described which gives improved correlation with the Expanded Disability Status Scale (EDSS). Classification of individual subjects into normal and MS subgroups is shown. Principal component analysis (PCA) and multiple discriminant analysis (MDA) are shown to give results superior to methods of MTR histogram analysis using traditional features such as peak height and peak location. Scatterplots confirm the improved separation between groups achieved using the MDA score. The histogram analysis provides a comparison of two classification approaches, based on PCA and MDA, to recognize differences between normal controls and the four different subgroups of MS disease (and all MS patients). Multiple linear regression of these PCs vs. EDSS established an MR-based measure of disease. Using a central 60-mm slab of brain tissue, the success rate of binary classification between control and MS subgroups using MDA was 75-95%, depending on which two groups were being compared. Multiple regression analysis of EDSS with the first three PCs as independent variables was significant (r = 0.83 for secondary progressive MS, and r = 0.80 for all MS patients).


Assuntos
Aumento da Imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Esclerose Múltipla/diagnóstico , Encéfalo/patologia , Avaliação da Deficiência , Análise Discriminante , Humanos , Esclerose Múltipla/classificação , Valores de Referência , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA