Akina Hirakawa

Parameter estimation of radiocardiogram using a minicomputer

Radiocardiography has been widely used as a method for the quantification of cardiac output by applying the principle of the dye dilution method. This paper deals with an automatic analyzing system of radiocardiograms and a parameter estimation procedure using a linear system made up of four compartments with two time delays as a model of transport process in the blood circulatory system. The parameter estimation procedure named the window method in frequency domain is very effective for shortening the computing time and can be easily performed using a minicomputer. Parameter sensitivity analysis is also applied to study behavior of parameters on the model. Some analyzed results of radiocardiograms are shown and it is verified that the procedure is sufficiently useful and efficient for routine clinical use.

Parameter Estimation of Radiocardiogram Using a Minicomputer

Abstract Radiocardiography has been widely used as a method for the quantification of cardiac output by applying the principle of the dye dilution method. In this paper, an efficient least square parameter estimation procedure in a frequency domain for a linear system with time delays, which is the model of transport process appearing in the radiocardiogram, is shown. The procedure is based on properties of Fourier transformation and a concept of a feature space, and parameter sensitivity analysis is applied to study behavior of parameters on the model. Some analyzed results of radiocardiograms are shown and it is verified that the procedure is sufficiently useful and efficient for routine clinical use.

Automatic Measurement System For Congenital Hip Dislocation Using A Computed Radiography

Acetabular angle which is a diagnostic parameter of congenital hip dislocation has been measured manually in conventional X-ray film system. Using digital image directly provided from a computed radiography, an automatic measurement system was developed for this parameter. The process of the measurement was completed within a reasonable time, and accurate enough. The system was combined with an image database, so that it would be a measurement tool of PACS.