Estimation of carotid diameter with heartbeat on longitudinal B-mode ultrasonic images.

Arteriosclerosis, i.e. degrading arterial elasticity, causes cerebral infarction and myocardial infarction. Premonition of arteriosclerosis is important because arteriosclerosis is never cured completely. We therefore propose a method to track the carotid diameter to evaluate the initial carotid elasticity accompanied with a person's heartbeat using the longitudinal B-mode ultrasonic images. If the diameter of carotid artery can be accurately estimated, it is possible to implies for initial inference of the presence of arteriosclerosis. In future studies, it has to be assessed with comparisons to anaother established method.

Propagation route estimation of heart sound through simultaneous multi-site recording on the chest wall.

While vibration source of the heart sound has been well-studied, the propagation route of the heart sound on the chest wall has not been clarified. In this study, we first measured the heat sound simultaneously at 64 positions on the chest wall of healthy subjects using 64 small accelerometers. We next calculated the delay times in the vibration propagation between all possible pair of neighboring positions. We proposed the estimation method for the propagation route of heart sound vibration on the chest wall by solving the shortest path problem in the graph-network theory only using such neighboring delay times. Applying to the recorded heart sound signals, we can obtain the estimated propagation route originated at the cardiac apex for the first heart sound, and that originated at aortic valve for the second heart sound.

Estimation of in vivo bone mineral density (BMD) and shape characterization for diagnosing osteoporosis by ultrasonic inspection.

A new method for estimating in vivo bone mineral density (BMD) and characterizing the shape of cancellous bone has been proposed using the results of ultrasonic inspection for the diagnosis of osteoporosis. The method is based on two-dimensional bone area fraction S (percent bone area between bone and bone marrow) calculated from the difference in the speed of ultrasonic wave propagation through cancellous bone. It was shown that the two-dimensional area fraction of a heel bone gives a good relationship to the BMD by DXA (dual energy x-ray absorptiometry) testing of human heel bone (calcaneus) and spine (vertebrae lumbar), as expressed by the relation, BMD (g/cm2) = 0.0167S for heel bone (r = 0.83), and BMD (g/cm2) = 0.0254S + 0.123 for the spine (r = 0.77). Shape characterization is based on the image simulation procedure employing eight random variables from a computer and the statistical results of fractal analysis for numerous cancellous bone patterns. We also demonstrate the validity of the shape characterization using autopsy specimens as a diagnostic tool for osteoporosis.