Pyloric stenosis: diagnosis by real time sonography, the pyloric muscle length method.

Real time sonography was performed for identification of pyloric stenosis in 100 infants referred for vomiting. In nine patients, imaging did not identify the pylorus. One of nine had pyloric stenosis. In 91 imaged patients, 40 had pyloric stenosis and 51 did not. Each imaged patient had determinations of the three described diagnostic pyloric muscle measurements: pyloric muscle diameter, pyloric muscle thickness, and pyloric muscle length. The determination of pyloric muscle length was the most accurate (97.8%); it had two false negatives, but no false positive results. Erroneous surgery was thereby avoided. We conclude that real time sonographic determination of pyloric stenosis is reliable and practical, and that pyloric muscle length determination is the most accurate of the currently available techniques.