| 摘要 |
PURPOSE: To prevent a flow value from being underestimated lower than its true value when a part of flow components is removed by a MTI filter. CONSTITUTION: Ultrasonic waves are transmitted to a testee' body by an ultrasonic wave probe 1, ultrasonic wave echo signals from the testee' body are received, the low frequency components of the ultrasonic wave echo signals are removed by MTI filters 9 and 10 based on filter characteristics selected in advance, and a flow dispersion valueσis thereby obtained by a CFM operation section 12 based on the ultrasonic wave echo signals from which the low frequency components are removed. Besides, the ratioαof a reference band width to the band width of selected filter characteristics is obtained, a connection factorγis computed by a correction factor computing section 18 by letting the band width ratioαbe multiplied by an adjusting factorβ, and a correction dispersion valueσ" is thereby computed by a correction multiplying section 20 by letting the aforesaid flow dispersion valueσ' be multiplied by the correction factorγ. By this constitution, the flow dispersion value can be prevented from being underestimated to a value parted from its true value because of the characteristics of the MTI filter, so that the reliability of diagnosis can thereby be enhanced. |
