Post-operative findings revealed type 1 ileal atresia, internal hernia, and necrosis at the ileo-jejunal junction as the primary cause of intestinal obstruction in this presentation. The ultrasound findings show aperistaltic bowel loops with air-fluid distension with the cocooned bowel loops surrounding the central abdomen.

Supine abdominal x-ray added value by showing diffuse gaseous distension of the proximal abdominal bowel loops characterized with bubbly/curvilinear intramural lucencies (pneumatosis intestinalis) plus thickened bowel walls (Rigler's sign) suggestive of grade 1 necrotizing enterocolitis (NEC).