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Fatty liver is a disease caused by the excess accumulation of fat in the human liver. The early diagnosis of fatty liver is very important, because fatty liver is the major marker linked to metabolic syndrome. We already proposed the ultrasonic velocity change imaging method to diagnose fatty liver by using the fact that the temperature dependence of ultrasonic velocity is different in water and in fat. For the diagonosis of a fatty liver stage, we attempted a feasibility study of the quantitative assessment of the fat content in the human liver using our ultrasonic velocity change imaging method. Experimental results showed that the fat content in the tissue mimic phantom containing lard was determined by its ultrasonic velocity change in the flat temperature region formed by a circular warming ultrasonic transducer with an acoustic lens having an appropriate focal length. By considering the results of our simulation using a thermal diffusion equation, we determined whether this method could be applied to fatty liver assessment under the condition that the tissue had the thermal relaxation effect caused by blood flow.

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A diagnostic system for fatty liver at an early stage is needed because fatty liver is linked to metabolic syndrome. We have already proposed a fatty liver diagnosis method based on the temperature coefficient of ultrasonic velocity. In this study, we fabricated a coaxial ultrasonic probe by integrating two kinds of transducers for warming and signal detection. The diagnosis system equipped with the coaxial probe was applied to tissue-mimicking phantoms including the fat area. The fat content rates corresponding to the set rates of the phantoms were estimated by the ultrasonic velocity-change method.

[Purpose] The aim of this study was to estimate the optimal load for exercise therapy based on cardiopulmonary exercise testing (CPX). [Subjects and Methods] Thirty-four patients were subjected to CPX, echocardiography and ankle brachial pressure index (ABI) measurements. Early diastolic filling velocity (E), atrial filling velocity (A), and peak early diastolic velocity of the mitral annulus (e') were measured by echocardiography, and then E/A and E/e' were calculated. The relationships between the optimal load for exercise therapy and the echocardiographic indexes and ABI were analyzed using multiple regression and their accuracies were examined.[Results] Independent determinants of the optimal load for exercise therapy were E/e' and ABI. Multiple regression determined the optimal load for exercise therapy as 21.98-1.06×E/e'+23.70×ABI (adjusted R 2 =0.365).[Conclusion]The results suggest that the optimal load for exercise therapy for inpatients with heart disease can be estimated from E/e' and ABI.