The Prevalence of Clinically Relevant Incidental Findings on Chest Computed Tomographic Angiograms Ordered to Diagnose Pulmonary Embolism

Abstract

Chest computed tomographic angiograms (CTAs) are frequently ordered for evaluation of suspected pulmonary embolism (PE) in the emergency department, but non-PE findings are often noted. Our objective was to determine the prevalence and management implications of incidental findings on chest CTAs ordered to assess for PE. In a cross-sectional study, we reviewed 589 pulmonary CTAs that were ordered in the emergency department of a tertiary care hospital. We measured the prevalence of PE and placed other findings into the following 3 categories: (1) findings that provided potential alternative explanations for acute symptoms, (2) incidental findings that required clinical or radiologic follow-up, and (3) other findings that required less urgent or no follow-up. We reviewed all newly diagnosed pulmonary nodules and significant thoracic adenopathy and determined standard recommended clinical follow-up. Pulmonary embolism was found in 55 of 589 CTAs (9%). A total of 195 CTAs (33%) had findings that supported alternative diagnoses. A total of 141 patients (24%) had a new incidental finding that required diagnostic follow-up, including 73 patients (13%) with a new pulmonary nodule and 51 patients (9%) with new adenopathy. Using current clinical guidelines, follow-up computed tomography or another procedure would be recommended for 96% of patients with new incidental pulmonary nodules. The CTAs that are ordered in the emergency department are more than twice as likely to find an incidental pulmonary nodule or adenopathy than a PE. Systematic approaches should be developed to help primary care physicians contend with a growing number of clinically relevant incidental radiologic findings.