Infantile hypertrophic pyloric stenosis: evaluation of sonographic criteria.

Sonography has become an important diagnostic adjunct in the evaluation of vomiting infants who are suspected to have infantile hypertrophic pyloric stenosis (IHPS). Two commonly used sonographic criteria, viz. pyloric diameter (D) and pyloric muscle wall thickness (T) were evaluated in 14 consecutive vomiting infants. The D and T were significantly larger in the IHPS group compared to the non IHPS group (1.40 +/- 0.34 cm vs 0.95 +/- 0.19 cm, p = 0.04; 4.4 +/- 1.1 mm vs 2.5 +/- 0.6 mm, p less than 0.01). By a combination of sonographic criteria (D greater than or equal to 1.2 cm & T greater than or equal to 3 mm), all the 4 non IHPS patients and 9 out of 10 IHPS patients were correctly diagnosed. The positive and negative predictive values were 1.00 and 0.80, respectively. However, using reported diagnostic criteria of D greater than or equal to 1.5 cm or T greater than or equal to 4 mm would have missed 60% and 20% of the IHPS cases, respectively. With proper choice of diagnostic criteria, sonography is a useful diagnostic tool in the evaluation of vomiting infants for IHPS patients.