Although traditional abdominal x-rays are of limited value in assessment of patients with acute abdominal pain, such x-rays are ordered frequently. These researchers compared the traditional three-view abdominal x-ray series (upright chest x-ray, supine and upright abdominal x-rays) with unenhanced helical computed tomography (CT) in 91 adults who presented to an emergency department with acute nontraumatic abdominal pain. Radiographic studies were interpreted by radiologists who were blinded to all clinical information except abdominal pain. Final diagnoses were assigned according to additional evaluation (including surgical and pathology findings) and clinical follow-up.
Final diagnoses were established in 50 cases; the most common diagnoses were appendicitis, diverticulitis, pancreatitis, cancer, and renal stones. CT illustrated the correct diagnosis in 48 of the 50 patients with specific final diagnoses (sensitivity, 96%), and showed no cause for acute pain in 39 of 41 patients without specific final diagnoses (specificity, 95%). In contrast, the sensitivity and specificity of traditional radiography were 30% and 88%, respectively.
The authors believe that this is the first prospective head-to-head comparison between plain films and CT in patients with acute abdominal pain. The results confirm what we knew intuitively: CT is more accurate than plain films. Although CT is more expensive and exposes patients to higher radiation doses, it makes little sense to order plain films when it’s likely that the patient will end up undergoing CT anyway.
Reference:
MacKersie AB et al. Nontraumatic acute abdominal pain: Unenhanced helical CT compared with three-view acute abdominal series. Radiology 2005 Oct; 237:114-22.