Identification of the heart wall and chamber based on temporal change of ultrasonic scatterer distribution

Abstract

In most current methods for evaluating the cardiac function by ultrasound, the heart wall area is identified manually by an examiner. To eliminate examiner dependence and to improve usability, an automatic heart wall identification method is desirable. Identification based on only echogenicity often fails because of low echogenicity of some areas of the heart wall. In the present study, to determine more essential features, we focused on the relative temporal change of ultrasonic scatterer distribution and proposed three features for identification of the heart wall and the chamber: cross-correlation of RF signals, that of envelopes, and spatial dispersion of movement vectors in small regions. In an in vivo experiment, using echogenicity and the three features, we identified the heart wall and the chamber in the left ventricular long-axis view, resulting in criteria of separability J of 1.69, 1.40, and 3.02 using these features compared with the result of 0.979 using echogenicity.

A method for the non-contact measurement of two-dimensional displacement of chest surface by breathing and heartbeat using an airborne ultrasound

“…Therefore, measurement of small displacement using phase difference is employed in this research. [35][36][37][38][39][40][41][42][43][44] After rough position determination from the brightness pixel, each part of the cross-correlation functions that compose the pixel is focused. Then, phase difference between the part and that in the next cross-correlation function that forms the next image is calculated.…”

Local two-dimensional distribution of propagation speed of myocardial contraction for ultrasonic visualization of contraction propagation

“…Ultrasonic diagnosis using medical ultrasound is highly useful because it is non-invasive in vivo, the equipment is comparatively inexpensive, and the minute movements and temporal changes of organs and blood vessels can be captured repeatedly in real time. [6][7][8][9][10][11][12][13] The representative heart disease is an ischemic heart disease, and the important condition is myocardial infarction. The lesion where myocardial infarction occurs is known as the ischemic region, injured region, and infarct region in the order of disease progression.…”

Evaluation of error factors depending on ultrasonic transmitted beamwidth in measurement of myocardial minute velocity

“…A diagnosis using echocardiography has the advantage of noninvasive and repetitive application compared with other diagnostic imaging methods. Ultrasonic measurement methods for the evaluation of cardiac function such as the characterization of the heart, 1) the visualizations of the blood flow in the heart lumen, [2][3][4] and the measurements of the propagation of the contraction on the myocardium, [5][6][7][8][9] have been studied.…”