Ultrasound diagnosis of hypertrophic pyloric stenosis: real-time application and the demonstration of a new sonographic sign.

The diagnosis of hypertrophic pyloric stenosis (HPS), a common problem of infancy, is usually based on medical history. When the diagnosis is in question a barium upper gastrointestinal series has been the diagnostic imaging procedure of choice. In this study real-time ultrasound was used in 27 infants in whom pyloric stenosis was suspected. The published criteria for the ultrasound diagnosis of pyloric stenosis were used to evaluate the results. Fourteen examinations were true-positive, 12 were true-negative, and one was false-negative. The authors termed the hypertrophied muscle, which was demonstrated in longitudinal section, the "ultrasonic cervix sign" of hypertrophic pyloric stenosis. It was concluded that real-time ultrasound is a simple and accurate method for the diagnosis of HPS and should be the initial imaging procedure.