Trends in the Rates of Radiography Use and Important Diagnoses in Emergency Department Patients With Abdominal Pain

BACKGROUND: Computed tomography (CT) and ultrasound (US) are used in emergency departments (ED) to aid in the diagnosis of patients with abdominal pain. OBJECTIVES: To describe trends in CT and US use in United States EDs and determine if higher test use is associated with higher detection rates for intra-abdominal illnesses commonly detected on CT and US and lower hospital admission rates. RESEARCH DESIGN: Retrospective study using the 2001 to 2005 National Hospital Ambulatory Medical Care Survey, a nationally representative sample of ED encounters. SUBJECTS: ED patients presenting with abdominal pain. MEASURES: Annual rates of and trends in CT and US use, rates of intra-abdominal illnesses, hospital admission rate. RESULTS: Abdominal pain visits accounted for 38.8 million encounters; 17.8% received a CT and 11.7% received an US. CT use increased from 10.1% in 2001 to 22.5% in 2005 (P < 0.001). US use increased from 11.1% in 2001 to 13.6% in 2005 (P = 0.002). During the same period, detection rates for appendicitis, diverticulitis, and gall bladder disease did not increase and admission rates did not decrease. CONCLUSION: Despite a more than doubling in CT use and increases in US use, there was no increase in detection rates for appendicitis, diverticulitis, and gall bladder disease nor was there a reduction in admissions.