Sonography of Hyperyrophic Pyloric Stenosis

Babies with hypertrophic pyloric stenosis (HPS) are generally healthy, normally developing infants in whom, suddenly, at the end of the first month of life, projectile vomiting develops. Clinically, a small “olive-shaped” tumor may be palpable. In this study, real-time ultrasound imaging was used in the evaluation of 57 cases of suspected HPS. The target sign, a hypoechoic ring of hypertrophied pyloric muscle, with a wall thickness of 4 mm or greater, proved to be a positive finding for hypertrophic pyloric stenosis. A pyloric channel length, or cervix sign, of greater than 1.4 cm was also a positive criterion for HPS. At the Children's Hospital of Philadelphia, we diagnosed 24 positive and 33 negative cases with 100% accuracy. High-resolution real-time ultrasound should be the first imaging modality used when evaluating cases of suspected HPS.