Avaliação de parâmetros ultra-sônicos utilizados na caracterização de tecidos ósseos

Abstract

Ultrasound transmission in human bodies has been studied for several decades in order to facilitate diagnosis. It has also been used to evaluate bone density and to diagnose early osteoporosis and future fracture risks. For this study, a system to generate, receive and amplify ultrasonic signs for speed of sound assessment and broad band ultrasound attenuation (BUA) was developed. Transmission of ultrasonic signals was performed by coupling using ultrasound gel and water (acoustic tank) and the sample placed between two transducers, one for transmission and the other for reception. Due to the high rate of the dispersion of ultrasonic measures, some reference material having the characteristics of the speed of sound and broad band ultrasound attenuation, similar to the heel bone that will be used for equipment calibration and follow-up of bone measure will have to be found. Ultrasonic parameters were used to evaluate bone consolidation (tibia of a sheep), in different periods and several kinds of fractures. Temperature and reproducibility using different materials were used to customize the system. Measures of volunteers's heel bone speed and broad band ultrasound attenuation showed results consistent with the ones from literature. Several analyses with little changes in geometric, signal and transducer frequency conditions were performed in order to observe their influence on attenuation and speed measures. Those steps were carried out in order to try to relate the variations in attenuation measures to those obtained by other authors.

Massa óssea em relação aos dados antropométricos e capacidade cardiorrespiratória em estudantes de 8 a 15 anos de idade

“…A pQCT possui a vantagem de discriminar o osso trabecular do osso cortical, também calcula a densidade volumétrica real assim como a QCT, porém é ineficiente quando se trata de monitoramento (38,39) .…”