Figure 1. Ultrasonographic images of a 7-year-old boy with abdominal pain and typical transient small bowel intussusception. Image in transverse plain (a) shows the crescent-in-doughnut sign (cursors) and image in longitudinal plain (b) shows the sandwich sign (cursors). The diameter of the doughnut measured 0.84 cm and the thickness of the outer rim of the lesion measured 0.10 cm. There were no mesenteric lymph nodes.