Pyloric ratio: efficacy in the diagnosis of hypertrophic pyloric stenosis.

We sought to define a weight independent, highly sensitive and specific measurement to diagnose hypertrophic pyloric stenosis. A retrospective review of 87 children was performed. We determined the pyloric ratio (wall thickness/pyloric diameter) and its relationship to weight and compared it to standard criteria. The average pyloric ratios in normal children and in those with hypertrophic pyloric stenosis were 0.205 and 0.325, respectively (P < 0.001). A pyloric ratio of 0.27 yielded a sensitivity and specificity of 96% and 94%, respectively. The pyloric ratio maintained a linear relationship to weight in normal patients and those with hypertrophic pyloric stenosis. We conclude the pyloric ratio can be a highly sensitive, specific, and weight independent indicator of hypertrophic pyloric stenosis.