Investigation

Investigations include:

• biochemistry, etc, to assess dehydration
• plain abdominal radiology may reveal features of obstruction
• ultrasound scan of the abdomen, which may reveal a swiss-roll appearance. If the patient is clinically stable and perforation is not suspected, ultrasonography should be the initial diagnostic test for intussusception as this has a reported diagnostic accuracy of up to 100%. (1)
• barium enema, which may reveal the stack of coins sign. Barium enema is also a treatment.

Note - the finding of a target sign (variants according to appearance or imaging modality include bull’s eye sign, doughnut sign, crescent-in-doughnut sign, and multiple concentric ring sign) is characteristic of intussusception on plain-film abdominal x-rays or less commonly by computed tomography (CT) scanning. (2)

References

1. Tsou PY, Wang YH, Ma YK, et al. Accuracy of point-of-care ultrasound and radiology-performed ultrasound for intussusception: a systematic review and meta-analysis. Am J Emerg Med. 2019 Sep;37(9):1760-9.
2. Plut D, Phillips GS, Johnston PR, et al. Practical imaging strategies for intussusception in children. AJR Am J Roentgenol. 2020 Dec;215(6):1449-63.