Ultrasonography in the diagnosis of pyloric stenosis.

We evaluated 101 children for hypertrophic pyloric stenosis (HPS) at Arkansas Children's Hospital. Diagnosis was based upon a palpable epigastric "olive" characteristic of HPS, or sonographic measurements of the pylorus. In 28 children, the diagnosis was confirmed by physical examination alone; the remaining 73 had ultrasound examination. Pyloric measurements included muscle thickness, transverse diameter, and total length. Pyloric function was also studied during examination. Using a thickness of less than 4 mm, a diameter of less than 13 mm, and a length of less than 17 mm as normal criteria, 31 cases of HPS were correctly diagnosed by ultrasonography. In the remaining 42, no pyloric abnormality could be demonstrated on further evaluation.