…Ultrasound is a sound with a frequency of 20,000 Hz or higher. Its two characteristics, (1) its ability to travel in a straight line and (2) its ability to be reflected at the boundary between two media with different acoustic impedances, can be used to analyze the shape and movement of the heart's valves, walls, membranes, and large blood vessels. There are two methods for this: the M-mode method, which shows the movement of various parts of the heart in one dimension, and the two-dimensional method, which shows the heart or large blood vessels in two dimensions, i.e., in cross-sectional planes. In addition to these, the Doppler method, which displays blood flow as a waveform, has recently become available at the same time. Echocardiography has become able to provide useful information non-invasively in the diagnosis of almost all heart diseases, including congenital heart diseases, which previously required invasive diagnostic methods such as cardiac catheterization. … *Some of the terms used in reference to the "M-mode method" are listed below. Source | Heibonsha World Encyclopedia 2nd Edition | Information |
…超音波とは周波数2万Hz以上の音であり,超音波のもつ,(1)直進性,(2)音響インピーダンスの異なる二つの媒質の境界面で反射される,という二つの特性を利用して,心臓の弁,壁,膜および大血管の形態と運動を分析することができる。本法には,一次元的に心臓内各部の運動を表現するM‐モード法と,二次元的,すなわち心臓あるいは大血管を断層面でとらえる方法の二つがあるが,近年ではさらにこれらに加え,血流を波形表示するドップラー法が同時に行えるようになった。心エコー図法により,従来心臓カテーテル法など観血的診断法が必要であった先天性心疾患をはじめとするほとんどすべての心疾患を診断するにあたって,有力な情報を非観血的に提供できるようになった。… ※「M-モード法」について言及している用語解説の一部を掲載しています。 出典|株式会社平凡社世界大百科事典 第2版について | 情報 |
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