八木 登志員, 吉川 純一, 吉田 清, 赤阪 隆史, 赤土 正洋, 深谷 隆, 前西 文秋, 加藤 洋, 城 泰子

Toshikazu YAGI, Junichi YOSHIKAWA, Kiyoshi YOSHIDA, Takashi AKASAKA, Masahiro SYAKUDO, Takashi FUKAYA, Fumiaki MAENISHI, Hiroshi KATO, Yasuko JYO

神戸市立中央市民病院循環器センター

Department of Cardiology, Kobe General Hospital

キーワード : Power-mode imaging, Two-dimensional Doppler color flow mapping, Clutter, Filter, Optimum gain

The usefulness and limitation of power-mode imaging in two-dimensional Doppler color flow mapping was investigated. The size of blood flow area obtained both by power-mode imaging and velocity-mode imaging was largely affected with the characteristic of the moving target indicator filter (MTI filter). The blood flow area on power-mode imaging using the L filter (L-MTI filter, cut off frequency: 200 Hz) became clearly larger than using the H filter (H-MTI filter, cut off frequency: 600 Hz). The blood flow area on velocity-mode imaging using the H filter was light and very large, and using the L filter was dark and small. Power-mode imaging is more senstive to detect low velocity than velocity-mode imaging in color fiow mapping. However, the power value obtained by this method might be easily affected by clutter signals, although this could be prevented by using the H filter. The optimum gain setting was also difficult in this mode. In conclusion, these power-mode probrems should be always kept in mind when one use the power-mode.