Hypertrophic pyloric canal stenosis should be suspected in the first weeks if the neonate presents with projectile vomiting and poor feeding.

Ultrasound is the best modality to assess the pylorus. The exam is performed after a copious meal (milk) to distend the stomach and allow a good sonographic window to visualize the pylorus.

Pylorospasm may mimic pyloric canal stenosis on imaging, so follow up and clinical correlation may be helpful if this is suspected. Transient pylorospasm should not present with the classic clinical features of pyloric canal stenosis.