Air and bones, which limit echo penetration to the lesion, are the major components of the thorax. Recently, however, there have been many reports concerning the valid application of ultrasonography for evaluation of chest diseases. In this paper, we report the usefulness of ultrasonography to analyze thoracic lesions based on our experience. Generally, ultrasonography is a method providing high resolution and real-time images. Using these characteristics, we tried to obtain physiological information concerning the hemodynamics of the right heart system. We addressed the results of our studies using ultrasonography as follows; 1) relationship between ventilatory change of IVC and central venous pressure, 2) estimation of pulmonary arterial pressure by measuring the size of the pulmonary artery, 3) dynamic changes of SVC configuration.