Published in:
01-01-2021 | Pyloric Stenosis | Classics in Abdominal Radiology
The caterpillar sign
Published in: Abdominal Radiology | Issue 1/2021
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Caterpillar sign can be seen with infantile hypertrophic pyloric stenosis (IHPS) on abdominal plain radiographs or upper gastrointestinal fluoroscopic studies. In the setting of IHPS, the stomach may appear dilated and air-filled with undulating borders on plain radiographs or upper gastrointestinal studies, suggestive of gastric outlet obstruction (Fig. 1). This appearance of the stomach has been likened to a caterpillar (Fig. 2). The undulating borders are the result of vigorous, hyperperistaltic gastric waves that abruptly discontinue at the pylorus [1, 2].
Fig. 1
Abdominal radiograph demonstrates a dilated, air-filled stomach with undulating borders, in a case of IHPS, consistent with caterpillar sign
Fig. 2
Photograph of a caterpillar
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