The reliable sonographic diagnosis of hypertrophic pyloric stenosis.

Fifty-five infants who presented to the Oklahoma Children's Memorial Hospital with vomiting and the clinical suspicion of hypertrophic pyloric stenosis (HPS) were evaluated using real-time ultrasound. Previously published criteria for the sonographic diagnosis of HPS were evaluated in these patients. The anterposterior diameter measurement of 1.5 cm or greater proposed by Strauss et al. had an accuracy of 36/50 (72%). The 4-mm or greater wall thickness measurement of Blumhagen et al. was correct in 46/50 (92%) of cases. A proposed criterion, the true pyloric muscle (TPM) length of 2.0 cm or greater was accurate in 33/33 cases. Application of the TPM length criterion should improve the reliability of sonographic diagnosis of HPS and decrease the need for radiographic studies.