Using patient characteristics to predict usefulness of abdominal computed tomography in children.

OBJECTIVE The study goal was to determine whether clinical symptoms, physical findings, or laboratory values predict the usefulness of abdominal computed tomography (CT) scans in children. METHODS We conducted a retrospective review of pediatric patients who received an abdominal CT scan between June 2009 and November 2011 at an urban medical center. A panel of pediatric hospitalists independently categorized each CT read as: (1) necessary for diagnosis; (2) unnecessary but helpful for diagnosis; or (3) neither necessary nor helpful for diagnosis. Two multiple logistic regression models examined 21 clinical variables to assess their ability to differentiate between: (1) necessary and unnecessary CT scans; and (2) helpful and unhelpful CT scans. RESULTS A total of 399 CT scans were analyzed. Seventy (18%) of these were categorized as necessary, 103 (26%) as unnecessary but helpful, and 226 (57%) as neither necessary nor helpful. Three variables were strongly correlated with necessary CT scans: leukocytosis, peritoneal signs, and male gender. The probability of a CT scan being necessary was 57% in patients with all 3 findings and 8% in those with none. Three variables were also strongly correlated with unnecessary but helpful CT scans: history of abdominal surgery, tachypnea, and leukocytosis. The probability of a CT scan being helpful was 84% in patients with all 3 findings and 35% in those with none of the 3 findings. CONCLUSIONS The majority of abdominal CT scans were unnecessary and unhelpful. Knowing which clinical variables correlate strongly with necessary or helpful abdominal CT scans may assist clinicians in deciding whether to order this test; however, the predictive power of these variables remains relatively low.