Soetanto K, Reid J M
Biomedical Engineering and Science Institute, Drexel University, Philadelphia, PA 19104.
Ultrasound Med Biol. 1991;17(4):355-66. doi: 10.1016/0301-5629(91)90135-j.
The characteristics of the sonographic image representation of a point reflector caused by beam refraction when the reflector is placed behind a cylinder, are investigated. This cylinder acts on the ultrasonic beam as a lens, which explains the displacement in the observed reflector location(s). A mathematical model was constructed for a sonogram containing a cylindrical object with sound propagation speed different from its surroundings, and an experiment was designed to show the resulting inaccurate positions of the point reflector image. The image representation depends on the ratio of the sound speed in the cylinder to that of its surroundings. Depending on the location of the point reflector, additional artifacts are also observed. These artifacts occur in different regions (i.e., into two groups of regions for higher sound speed, and four groups of regions for lower sound speed in the cylinder).
研究了点反射体置于圆柱体后方时，由波束折射引起的超声图像表示的特征。该圆柱体对超声束起透镜作用，这解释了观察到的反射体位置的位移。构建了一个包含声速与其周围环境不同的圆柱形物体的超声图像数学模型，并设计了一个实验来展示点反射体图像产生的不准确位置。图像表示取决于圆柱体内声速与其周围环境声速的比值。根据点反射体的位置，还观察到了额外的伪像。这些伪像出现在不同区域（即，对于圆柱体内声速较高的情况分为两组区域，对于圆柱体内声速较低的情况分为四组区域）。
