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The measurement of thermal and ultrasonic properties of biological tissues is essential for the assessment of the temperature rise induced in vivo by diagnostic ultrasound. In this paper, we present measurements of thermal conductivity, thermal diffusivity, speed of sound and ultrasonic attenuation of fresh ex vivo porcine tissue, namely 'muscle' (from abdomen and leg), 'skin with subcutaneous fat' (from abdomen and leg), 'abdominal fat' and 'bone'. The measurements of the thermal properties of biological tissue samples are based on a transient method. Thermal property measurements show that subcutaneous fat has the lowest thermal conductivity (0.23 W m(-1) K(-1)), while muscle gives the highest values (0.46 W m(-1) K(-1)). Thermal diffusivity of muscle tissue recorded the highest value among the studied tissues (0.16 mm(2) s(-1)) while that of skin with subcutaneous fat gave the lowest value (0.11 mm(2) s(-1)). A scanning acoustic macroscope was used to measure attenuation coefficient and speed of sound for the tissue samples. The results for the speed of sound are broadly similar to those reported in the literature. The power law dependence of the attenuation coefficient of the form eta = a f (b) as a function of frequency was found to be more appropriate than the linear fit in this study.

This study showed for the first time that compared to control subjects, patients with CSX have higher hs-CRP serum levels, increased mean common carotid artery IMT and increased arterial stiffness. The role of these abnormalities in the pathogenesis of CSX deserves investigation.

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Theoretical formulations are developed, based on mathematical models of inhomogeneous continua for the expected angular variation of bulk scattering from human and animal tissues. These results are compared with experimental data on angular scattering from liver, muscle, and blood, reported in a companion paper [J. Acoust. Soc. Am. 79, 2034-2047 (1986)], and deductions are drawn as to the appropriateness of the various models for representing the mechanical structure of the different tissues. On this basis, the experimental data and theoretical formulations are used to derive estimates, appropriate to the frequency range of observation (4-7 MHz), of correlation distance (or effective scatterer spacing) d, the local variabilities of density and compressibility, gamma rho = delta rho/rho and gamma kappa = delta kappa/kappa 0, and their ratio gamma rho/gamma kappa. For blood, liver, and skeletal muscle, the values derived at 6 MHz for d are approximately 5, 55, and 75 microns and for gamma rho/gamma kappa are 0.5, 0.15, and 0.28, respectively. These results are, in particular, at variance with the commonly made assumption, based on evidence from low-frequency measurements, that the ratio gamma rho/gamma kappa is sufficiently small that density terms can be ignored in calculations of human tissue scattering.

This study demonstrated significant biventricular diastolic and biatrial systolic and diastolic dysfunction in MFS patients. Our findings suggest that MFS affects diastolic function independently. Diastolic abnormalities could be attributed to fibrillin-1 deficiency and dysregulation of transforming growth factor-beta activity in the cardiac extracellular matrix.

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Our study showed a uniform reduction in biventricular deformation in MFS. These findings suggest that assessment of myocardial function using advanced echocardiographic techniques could be more accurate in MFS patient evaluation than conventional echocardiography alone.