HRCT findings in the lungs of primary care patients with lower respiratory tract infection

PURPOSE: To survey the prevalence and type of lung patterns detectable at high-resolution CT (HRCT) in a primary care population seeking help for cough and fever. MATERIAL AND METHODS: The HRCT patterns of 103 patients obtained at the primary visit to a municipal health centre for cough and fever were evaluated. Forced expiratory examinations were obtained in 93 patients. RESULTS: Lower respiratory tract infection (LRTI)-related findings (present at inclusion, healed at follow-up, not explained by any other factor) were seen in 19 patients (18.7%), of whom 11 also showed opacities, even though of lesser extent, at conventional chest radiography. The following patterns were found: ground-glass opacity (58%), discrete consolidations (52%), confluent consolidations (16%; 1 case with an air bronchogram), air space nodules (10%), peribronchovascular thickening (37%), tree-in-bud pattern (26%), free pleural fluid (5%), and septal thickening (5%). An expiratory mosaic pattern was seen in 19 (20%) out of 93 patients. In addition, lymph node enlargement (>1 cm) was recorded in 7 patients out of 103. CONCLUSION: HRCT is more sensitive than chest radiography in detecting LRTI-related lung lesions in a primary care population. The pattern typically comprises subtle scattered polymorphous opacities with varying attenuation affecting several lung segments. LRTI-related HRCT pattern deserves consideration as a differential diagnostic alternative in patients examined due to any lower respiratory tract symptoms.