31 research outputs found
Relations between increase in femoral neck bone mineral density and decrease in hip fracture incidence during treatment with strontium ranelate
No full textpeer reviewe
Sensibilidade e especificidade do índice de massa corporal (IMC) no diagnóstico de obsidade em idosos: comparação com a absortometria por raio-x dupla energia (DEXA) e proposta de novos pontos de corte
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Nutrição.Durante o envelhecimento ocorrem diminuições da massa livre de gordura (MLG), água corporal total e densidade mineral óssea (DMO) e aumento da gordura corporal (GC). O excesso de GC, definida como obesidade, está associado a diversas patologias, entre elas: hipertensão, diabetes tipo II, dislipidemias e cardiopatias. O Índice de Massa Corporal (IMC), comumente usado para diagnóstico de obesidade em populações adultas, não faz discriminação entre GC e MLG, sexo ou faixa-etária e por tais motivos apresenta limitações, principalmente em idosos. Deste modo, o presente estudo teve por objetivo geral verificar a correlação entre o índice de massa corporal (IMC) e o método da absortometria por raio-X de dupla energia (DEXA) em indivíduos com mais de 60 anos, de ambos os sexos, visando à determinação de pontos de cortes sensíveis e específicos para o diagnóstico de obesidade. A amostra foi composta por 60 homens e 120 mulheres, com idade entre 60 e 81 anos, selecionados de forma aleatória sistemática, a partir de lista nominal dos sujeitos, pertencentes a quatro Grupos de Terceira Idade de Florianópolis-SC. As variáveis estatura e peso corporal foram mensuradas no período da manhã, junto ao Centro de Desportos da Universidade Federal de Santa Catarina e as medidas da DEXA foram realizadas no período da tarde no Centro de Diagnóstico por Imagem - SONITEC . Os dados foram analisados por meio do programa SPSS versão 11.5, adotando-se um nível de significância de p<0,05. Foi verificada a sensibilidade e a especificidade dos pontos de corte propostos pela Organização Mundial de Saúde e pelo Nutrition Screening Initiative por meio da Curva ROC (Receiver Operating Characteristic) bem como a concordância dos diagnósticos por meio do teste kappa. Os homens apresentaram IMC médio de 26,5±2,8 kg/m2 e um %GC médio de 23,02±5,8 enquanto que as mulheres apresentaram 27,4 3,9 kg/m2 de IMC e 37,3 6,9 de %GC. O coeficiente de concordância ( ) demonstrou baixos valores para os pontos de corte estudados, onde o melhor resultado apresentado foi para o IMC de 27kg/m2 na população masculina ( = 0,426), contudo este resultado pode ser considerado regular. A sensibilidade do IMC de 30 kg/m2 foi de 31,6% e 28,9% enquanto que a especificidade foi de 97,5% e 100% para homens e mulheres respectivamente. Novamente o ponto de corte de 27 kg/m2 para homens foi o que apresentou melhores valores 73,7% e 72,5%, já para mulheres o IMC de 25 kg/m2 apresentou 76,3% e 100% de sensibilidade e especificidade, respectivamente. Baixos valores de sensibilidade para idosos foram encontrados na literatura, semelhantes aos deste estudo. Através da curva ROC determinaram-se os pontos de corte de 27,5 kg/m2 para homens e 23 kg/m2 para mulheres como valores de melhor sensibilidade (73,7% e 87,7% para homens e mulheres) e especificidade (82,5% e 100% para homens e mulheres) para o diagnóstico de obesidade. Desta forma conclui-se que os pontos de corte do IMC analisados possuem baixa sensibilidade, podendo oferecer diagnóstico incorreto quanto à obesidade. Os pontos de corte propostos são mais sensíveis e específicos para a população idosa, propiciando diferenciação quanto ao sexo, podendo ser adotados para o diagnóstico desta patologia, quando a população tiver características semelhantes à estudada. During the aging happen decreases on the fat free mass (FFM), total body water and bone mineral density (BMD) and increase of the body fat (BF). The excess of BF, defined as obesity, is associated with several diseases like: hypertension, diabetes type II, high cholesterol and cardiovascular diseases. The Body Mass Index (BMI), is commonly used to diagnose obesity in populations, however it doesn't make some discrimination between BF and FFM, gender or age and, for this reasons, can make some mistakes on the diagnoses, mainly in elderly people. The present study had as objective to verify the correlation between BMI and the Dual energy X-ray absortometry (DEXA) in the people over than 60 years old, of both gender, and to establish better cut-offs for this population. The study counted with 60 men and 120 women with age between 60 and 81 years, selected by systematic aleatory way, from a nominal list of the subjects by four groups of third age of Florianópolis-SC, Brazil. The variables stature and body weight were verify on the morning, on the Sports Center of Santa Catarina's Federal University and the DEXA were accomplished on afternoon, in the same day, on the Center of Images Diagnosis - SONITEC . The data were analyzed through statistical packages SPSS version 11.5, and was considered significant the confidence interval of 95% (p <0,05). The sensibility and specificity of the cuts-off, proposed by WHO (25 kg/m2 and 30 kg/m2) and the Nutrition Screening Institute - NSI, 1992 - (27 kg/m2) was verified through ROC curve (Receiver Operating Characteristic) as well as the agreement of the diagnoses through the kappa's test ( ). The men presented a BMI medium of the 26,5±2,8 kg/m2 and a %BF of the 23,02±5,8% while the women presented 27,4±3,9 kg/m2 of BMI and 37,3±6,9 of %BF. The Kappa's coefficient demonstrated low values for the studied cuts-off, and the best result was for the 27kg/m2 cut-off of BMI in the masculine population ( = 0,426). However, this result can only be considered as regular. The sensibility of the cut-off 30 kg/m2 was 31,6% and 28,9% for men and women while the specificity was 97,5% and 100%. The 27 kg/m2 cut-off for men presented better values again, 73,7% of the sensibility and 72,5% of specificity, but in the women, the 25 kg/m2 cut-off it presented 76,3% and 100% of sensibility and specificity respectively. Low values of sensibility for elderly were found on the literature, like this study. Using the ROC curve could be determined the cuts-off of BMI of the 27,5 kg/m2 for men and 23 kg/m2 for women as better values of the sensibility (73,7% and 87,7% for men and women) and specificity (82,5% and 100% for men and women) to discriminate obesity. For this way, could be concluded that the analyzed cuts-off of BMI had low sensibility and could offer incorrect diagnosis of obesity. The proposed cuts-off are more sensitive, and specific for the elderly people, and make differentiation between gender, so could be adopted for the diagnosis of this pathology when the population has characteristics similar to this studied
Fuzzy clustering-based segmented attenuation correction in whole-body PET
No full textSegmented-based attenuation correction is now a widely accepted technique to reduce noise contribution of measured attenuation correction. In this paper, we present a new method for segmenting transmission images in positron emission tomography. This reduces the noise on the correction maps while still correcting for differing attenuation coefficients of specific tissues. Based on the Fuzzy C-Means (FCM) algorithm, the method segments the PET transmission images into a given number of clusters to extract specific areas of differing attenuation such as air, the lungs and soft tissue, preceded by a median filtering procedure. The reconstructed transmission image voxels are therefore segmented into populations of uniform attenuation based on the human anatomy. The clustering procedure starts with an over-specified number of clusters followed by a merging process to group clusters with similar properties and remove some undesired substructures using anatomical knowledge. The method is unsupervised, adaptive and allows the classification of both pre- or post-injection transmission images obtained using 137Cs single-photon sources into main tissue components in terms of attenuation coefficients. A high quality transmission image of the scanner bed is obtained from a high statistics scan and added to the transmission image. The segmented transmission images are then forward projected to generate new transmission sinograms to be used for attenuation correction in the reconstruction of the corresponding emission scan. The technique has been tested on a chest phantom simulating the lungs, heart cavity and the spine, the Rando-Alderson phantom, and whole-body clinical PET studies showing a clear reduction of noise propagation from transmission into emission data and allowing for reduction of transmission scan duration. Finally, the potential of the FCM method and its limitations as well as other prospective applications of the technique are discussed
Relationship between bone mineral density changes and fracture risk reduction in patients treated with strontium ranelate
No full textpeer reviewedObjective: Our objective was to analyze the relationship between bone mineral density (BMD) changes and fracture incidence during 3-yr treatment with strontium ranelate. Patients: Women from the strontium ranelate arm of the Spinal Osteoporosis Therapeutic Intervention study and the TReatment Of Peripheral OSteoporosis study were evaluated. Outcome Measures: The outcome measures included BMD at the lumbar spine, femoral neck, and total proximal femur assessed at baseline and after a follow-up of 1 and 3 yr; semiquantitative visual assessment of vertebral fractures; and nonvertebral fractures based on written documentation. Results: After 3 yr of strontium ranelate treatment, each percentage point increase in femoral neck and total proximal femur BMD was associated with a 3%(95% adjusted confidence interval, 1-5%) and2% (1-4%) reduction in risk of a new vertebral fracture, respectively. The 3- yr changes in femoral neck and total proximal femur BMD explained 76% and 74%, respectively, of the reduction in vertebral fractures observed during the treatment. Three-year changes in spine BMD were not statistically associated with the incidence of new vertebral fracture (P = 0.10). No significant associations were found between 3- yr changes in BMD and incidence of new nonvertebral fractures, but a trend was found for femoral neck BMD (P = 0.09) and for total proximal femur BMD (P = 0.07). An increase in femoral neck BMD after 1 yr was significantly associated with the reduction in incidence of new vertebral fractures observed after 3 yr (P = 0.04). Conclusion: During 3-yr strontium ranelate treatment, an increase in femoral neck BMD was associated with a proportional reduction in vertebral fracture incidence
A randomized double-blind controlled study of 6 months of oral nutritional supplementation with arginine and omega-3 fatty acids in HIV-infected patients.
No full textDXA parameters related to internal reference system as predictors of an in vivo variability of BMD measurement from a study on 3808 patients involving 75 centres
No full textpeer reviewe
Body composition by X-ray absorptiometry and bioelectrical impedance in chronic respiratory insufficiency.
No full textCentralized quality management of bone densitometry for clinical trial and private practice: The use of ISO standard by GECAP (Geneva Quality Assessment Program)
No full textpeer reviewe
