Hypertrophic Pyloric Stenosis:Pre- and Post-operative Sonographic Findings

The authors retrospectively analysed the ultrasonographic findings of 43 cases of surgically confirmed hypertrophic pyloric stenosis and their postoperative findings of sonograms taken at 1 month(n=40) or 3 months( n=5) after pyloromyotomy. In preoperative study, the thickened pyloric muscle was isoechoic or slight hypoechoic relative to liver on the midline longitudinal view and appeared as a “nonuniform acoustic ring” on the transverse view. The results of measurement in the all cases with hypertrophic pyloric stenosis were the pyloric thickness ≥3.8mm, the pyloric diameter ≥14mm, the pyloric channel length ≥16mm, the pyloric muscle volume ≥2.21Cm³ and the pyloric muscle index≥0.57, respectively. It usually reguired 1 month after operation for the hypertrophied muscle to resolve in 36 of 40 patients. The normalized pyloric muscle appered more hypoechoic than that of adjacent hepatic parenchyma, and the nonuniform echogenicity of the pyloric muscle disappeared. Five patients whose hypertrophied muscle did not return to normal range on 1 month's follw-up sonogram were follwed-up 3 months later again, and we have ascertained their resoluction in all of them. In concusion the pre-operative sonographic findings of infantile hypertrophic pyloric stensis were different quantitatively and qualitatively from those of post-operative follow-up ultrasound exam. High-resolution real time sonography is a safe and accurate method for the diagnsis of hypertrophic pyloric stenosis and useful in postpyloromyotomy follow-up.