Purpose or Case Report: Self-resolving ileocolic intussusception (ICI) represents a variant of intussusception. Although this transient form is encountered clinically on a sporadic basis, descriptive imaging criteria summarizing a cohort of self-resolving intussusceptions is lacking. This study aimed to characterize the imaging features of spontaneously resolving ICI and to assess inter-rater agreement among pediatric radiologists.
Methods & Materials: This IRB-approved retrospective study identified ultrasound (US) examinations with radiology reports positive for ICI. Exams were further evaluated to identify presence of self-resolving ICI, which was defined as US exam with positive ICI without surgical, sonographic or fluoroscopic reduction or exams in which no ICI was identified on fluoroscopy. Exams were excluded if they contained only small bowel intussusception or were performed at outside hospital with no reliable follow-up imaging. US exams consistent with short segment ICI were independently reviewed by six pediatric radiologists, with each study evaluated by two readers. A standardized REDCap form was used to record: measured length of the intussusceptum within the intussuscipiens, extent of measurement (full vs. partial), and involved quadrants (RLQ, RUQ, LUQ, LLQ, mid-upper, mid-lower). Interreader agreement was analyzed using weighted Cohen’s κ for categorical variables and intraclass correlation coefficients (ICC) for continuous length measures.
Results: A total of 78 exams were included (each study assessed by two readers). Among spontaneously resolving intussusceptions, 23% measured ≤3 cm and 77% measured >3 cm, with a median length of 4.1 cm (range 0–10.3 cm). Most (34/78, 43%) were centered in the RUQ, 42% (33/78)in the RLQ, 6% (5/78) in the mid-upper, and 8% (6/78) in other quadrants. Interreader agreement was substantial for quadrant documentation (κ = 0.72, 95% CI 0.50–0.88) and excellent for length measurement (ICC(2,1) = 0.84, 95% CI 0.70–0.91), indicating high consistency in imaging feature assessment among readers.
Conclusions: Self-resolving ileocolic intussusceptions have imaging features of short segment length and right-sided abdominal location (RLQ or RUQ) on retrospective review, with substantial-to-excellent inter-rater agreement across readers. Further research is needed to better understand clinical and imaging features of self-resolving ICI and to explore indicators that may predict the need for reduction.