Abstract 3236: Prevalence and Significance of Incidental Findings Detected on Non-Contrast Computed Tomography of the Chest and Abdomen in Asymptomatic Subjects: The Framingham Heart Study
Background: The prevalence and clinical significance of non-coronary incidental findings (IF) detected on non-contrast CT of the chest and abdomen in asymptomatic subjects and associated subject burden is unknown.
Methods: Non-coronary IF were detected on non-contrast CT of the chest and abdomen performed on 3429 asymptomatic Framingham Heart Study participants (48% female, mean age: 52.6 years). Those with IF were informed by mail, and a subsequent telephone interview was systematically conducted after six months; medical records were retrieved for all subjects reporting diagnostic testing. A panel of physicians reviewed the results of telephone interviews, radiology reports, and related medical records, to determine the nature and location of the IF, as well as the subsequent diagnostic testing, procedures, final diagnoses, and participant concerns.
Results: Overall, IF were reported in 732 subjects (21%), among them 521 (15.2%) and 331 (9.6%) subjects had IF on chest or abdominal CT. The most frequent findings were pulmonary nodules (22.1%), liver cysts (13.6%), renal (21%) lesions, and aortic aneurysms (8.1%). Subsequent diagnostic testing was recommended in 532 subjects (16.9%) and performed in 60.7% (323/532) of those subjects. Phone follow-up was completed in 97.2% and medical records were available in 89%. Overall, 499 diagnostic imaging tests were performed subsequent to the IF reporting (non-contrast CT, n=150 (30%); contrast-enhanced CT, n=142 (28.5%); abdominal ultrasound, n=141 (28.3%), and magnetic resonance imaging, n=23 (4.6%)). Further intervention was performed in 14/3149 subjects (0.44%) - biopsy n=4, endoscopy n=2, and surgery n=12). A new cancer was identified in 4 subjects (0.1%). Overall, 10% of subjects missed work or full-time responsibility and 14% incurred financial costs.
Conclusions: Non-coronary incidental findings, most often non-calcified pulmonary nodules, are frequently detected in asymptomatic subjects undergoing non-contrast CT of the chest and abdomen. Subsequent diagnostic testing, clinical significance of findings and burden for subjects as reported will inform an objective cost benefit analysis for screening of asymptomatic subjects with non-contrast chest and abdominal CT.