High grade stenosis of the colon on the left flexure through a progressed carcinoma. The ultrasound image shows the large expansion; in the left lower corner the endoscopic image is shown. It was taken after a stent was placed.
Stenosis is a reduction of the lumen of a tube-like part of the body. The extreme form of stenosis is called stricture. In some cases both words are interchangeable.
Source: Ultraschall im Netz