Ileocolic versus small-bowel intussusception in children: can US enable reliable differentiation?

To assess clinical and ultrasonographic (US) criteria that can be used to confidently differentiate ileocolic from small-bowel intussusception.

Institutional review board approval was obtained for this retrospective study, and the need to obtain informed consent was waived. US and clinical data for children given a diagnosis of intussusception in the years 2007 through 2011 were evaluated. The diameters of the intussusception and the inner fat core, the outer bowel wall thickness, and the presence or absence of lymph nodes inside the intussusception and mesentery were noted. The Student t test, the Mann-Whitney test, and the Levene test were used for comparison of parametric variables, while the χ(2) and Fisher exact tests were used for comparison of categoric data.

There were 200 cases of intussusception in 174 patients (126 boys, 48 girls; mean age, 17.2 months (range, 0 years to 7 years 1 month); 57 (28.5%) were small-bowel and 143 (71.5%) were ileocolic intussusceptions. Mean lesion diameter was 2.63 cm (range, 1.3-4.0 cm) for ileocolic versus 1.42 cm (range, 0.8-3.0 cm) for small-bowel intussusception (P < .0001). Mean fat core diameter was 1.32 cm (range, 0.6-2.2 cm) for ileocolic versus 0.1 cm (range, 0-0.75 cm) for small-bowel intussusception (P < .0001). The ratio of inner fat core diameter to outer wall thickness was greater than 1.0 in all ileocolic intussusceptions and was less than 1.0 in all small-bowel intussusceptions (P < .0001). Lymph nodes inside the lesion were seen in 128 (89.5%) of the 143 ileocolic intussusceptions versus in eight (14.0%) of the 57 small-bowel intussusceptions (P < .0001). Children with ileocolic intussusception had more severe clinical symptoms and signs, with more vomiting (P = .003), leukocytosis (P = .003), and blood in the stool (P = .00005).

The presence of an inner fatty core in the intussusception, lesion diameter, wall thickness, the ratio of fatty core thickness to outer wall thickness, and the presence of lymph nodes in the lesion may enable reliable differentiation between ileocolic and small-bowel intussusceptions.