Sauerbrei E E
J Ultrasound Med. 1985 Jan;4(1):29-34. doi: 10.7863/jum.1985.4.1.29.
Transverse ultrasound scans of the pelvis often demonstrate double images or an apparent widening of the structures deep to the bladder. The phenomenon occurs when the real-time transducer is placed on the midline of the abdominal wall. Most of the widening effect or split image is caused by refraction of sound at the interface between the abdominal wall muscle and the collection of fat deep to the muscle. Using Snell's Law, it is possible to calculate the amount of splitting for a given anatomic configuration. The phenomenon is most exaggerated when the object is furthest away from the transducer and when the curvature between muscle and fat is largest.
骨盆的横向超声扫描常常显示出双重图像，或者膀胱深部结构明显增宽。当实时换能器置于腹壁中线时就会出现这种现象。大部分增宽效应或分裂图像是由腹壁肌肉与肌肉深部脂肪聚集处之间的界面处声音折射所致。利用斯涅尔定律，可以针对给定的解剖结构计算分裂量。当物体离换能器最远且肌肉与脂肪之间的曲率最大时，这种现象最为明显。
