Pylorus Ultrasound

Pylorus Ultrasound is an exam that obtains images of the pylorus with sound waves. Affected infants display symptoms of vomiting, dehydration and weight loss between the ages of two to eight weeks. The wall and length of the pylorus are measured by the sonographer. This measurement gives the radiologist important information to properly diagnose pyloric stenosis.


  • The infant will lie flat or on their side on an exam table with the abdomen exposed.
  • A non-greasy gel will be applied to the skin during the exam.
  • The sonographer will use a hand-held transducer (probe) against the abdomen to obtain images of the pylorus.
  • The exam will be checked by a radiologist before the infant leaves the department.
  • The infant may be given water during the exam to obtain further information.


  • The infant needs to be NPO (nothing by mouth) two to three hours before the scheduled appointment.
  • Arrive 15 minutes prior to your scheduled appointment with a prescription if your doctor has given one to you.
  • Bring formula and things to keep infant comfortable (i.e., bottle, blanket, pacifier) after the exam is completed.


  • Let the technologist know:
    • If the infant has had any previous surgery.
    • If there is a strong family history of pyloric stenosis.
    • If projectile vomiting and weight loss are symptoms.
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