Fig. 4
From: Upper GI series in infants and children with vomiting: insights into ACR appropriateness criteria
Two different patients with gastric outlet obstruction. Upper row neonate with infantile hypertrophic stenosis; a) plain AP view shows air-filled stomach with wave-like contour (caterpillar sign) with paucity of abdominal gas distally; b) lateral view shows very narrowed pyloric canal (string sign, arrow) with delayed gastric emptying; c) ultrasound scan of the pylorus reveals elongated thickened pyloric canal, with length of 20 mm, transverse diameter of 11 mm and single wall thickness 4 mm. d, e) patient with idiopathic acquired gastric outlet obstruction; d) plain AP view shows dilated fluid filled stomach displacing the surrounding gas filled bowel loops; e) UGI series shows the dilated stomach with delayed gastric emptying