Figure 8c.  Variant forms of the outer ring. (a) Axial US scan shows an outer ring (arrowheads) that is hyperechoic relative to the adjacent liver (L). This appearance was seen when the child had an attack of colicky pain. (b) Axial US scan shows alternating hyperechoic and hypoechoic bands (arrows) produced by the layers of the bowel wall of the intussuscipiens and the everted limb of the intussusceptum (multilayered image). (c) Axial US scan shows a band of hyperechoic dots between the thin intussuscipiens (A) and the everted limb of the intussusceptum (B). Arrowheads indicate the outer ring.