谷口 信行

Nobuyuki TANIGUCHI

自治医科大学臨床検査部

Department of Clinical Laboratory Jichi Medical School

キーワード : Attenuation, Backscatter, Brightness, Measurement, Ultrasound intensity

Brightness is the basic factor used in evaluating ultrasonic images, which are qualitatively classified as anechoic, hypoechoic, or hyperechoic. We used the histogram mode of our equipment, which is convenient clinically, to estimate brightness quantitatively. Interpretation of our results requires knowledge of the mechanisms of brightness and scatter intensity and of the relationship between them. These values vary with number and size of the particles that comprise the target tissue or organ, not merely with transducer frequency. Brightness values also vary with gain, sensitivity time control, and other panel settings that are easily changed by the examiner. Although scatter intensity is also affected by attenuation in the organs, it is not affected by the settings of the machine. Estimation of "native" inter-examinee brightness or intensity in the target area requires knowledge of and correction for attenuation along the path to the target as well as for the brightness or intensity of the target area. Measurement of ultrasound brightness and intensity should prove useful in the quantitative estimation of organ character.