is a Clinical Instructor and is an Associate Professor of
Clinical Radiology in the Department of Radiology, University of
California, San Francisco, CA. Acute abdominal pain is a
frequent problem in childhood. The list of differential
diagnostic possibilities is long and varies significantly with
the patient's age and sex. Because it is often difficult to
reach a diagnosis on clinical grounds alone, and several of the
possible diagnoses require immediate surgical attention,
radiologists are often called upon to assist in the evaluation
of these patients. Historically, standard abdominal
roentgenography had been the cornerstone in the evaluation of
acute abdominal pain in children. While plain film can be useful
for finding free intraperitoneal air, evidence of bowel
obstruction, or abnormal abdominal calcifications, results may
be negative in up to 50% of patients. Cross-sectional imaging
techniques, including ultrasonography, have significantly
influenced the imaging approach in children with certain abdomi