From the case: Target (photo)

Used in the following article:

• Target sign (intussusception) - “ The target sign of intestinal intussusception, also known as the doughnut sign or bull's eye sign. The appearance is generated by concentric alt...”
• Target sign (disambiguation) - “ There are many bull's eye signs, also referred to as target signs: red bone marrow located in the shaft of long bone with central yellow marrow o...”
• Target sign (pyloric stenosis) - “ The target sign of pyloric stenosis is a sign seen due to hypertrophied hypoechoic muscle surrounding echogenic mucosa, seen in pyloric stenosis. ...”