Purpose: The purpose of this study was to determine which imaging stud
y, upper gastrointestinal series (UGI) or abdominal ultrasonography, (
US), is more cost-effective in diagnosing infantile hypertrophic pylor
ic stenosis (IHPS) using a decision analysis model. Methods: Probabili
ties were calculated from a review of the records of all infants less
than 6 months of age referred For UGI or US to rule out IHPS over a 3-
year period from January 1992 to December 1995. Cost-effectiveness was
determined from hospital charges for each imaging study and its possi
ble outcomes, Results: The positive predictive value of UGI was 1.0 an
d US was 0.98 in the 246 infants evaluated for possible IHPS. In patie
nts who had an initially normal study finding (UGI or US), 25% of pati
ents undergoing US first required a second study for persistent sympto
ms, whereas only 6% of patients who had a negative initial UGI finding
required a second study. Conclusions: Cost analysis found UGI to be m
ore cost-effective than US because fewer secondary studies were requir
ed. UGI provides information regarding other pathological conditions a
s compared with US. Copyright (C) 1997 by W.B. Saunders Company.