The usefulness of low-dose CT scan in elderly patientswith suspected acute lower respiratory infection in the emergency room

Objective: To evaluate the usefulness of low-dose CT (LDCT) for the diagnosis of acute lower respiratory infection (ALRI) in elderly patients in the emergency room (ER). Methods: A total of 160 consecutive patients (mean age: 75.969.2 years; range: 60-97 years), who were diagnosed to have ALRI by LDCT in the ER, were enrolled in this study. Initial chest radiograph (CR) and CT patterns of ALRI were analysed, and clinical courses of patients were assessed. Results: 49 patients showed negative CR, in whom the main CT patterns were diffuse bronchial wall thickening (n523), ground-glass opacity (n56), mixed centrilobular nodules and ground-glass opacity (n53), small consolidation (n58) or consolidation in the dependent lung (n59), while the other 111 patients with the main CT pattern of consolidation demonstrated pulmonary abnormality on CR. Pulmonary oedema (12.5%) and pleural effusion (23.1%) were associated. The rate of hospitalization, care in the intensive care unit, mortality and comorbidity were significantly higher in the CR(1)LDCT(1) group (88.3%, 36.1%, 18.2% and 59.5%) than in the CR(2)LDCT(1) group (55.1%, 8.2%, 2.0% and 38.8%; p#0.05). Conclusion: LDCT was useful for the early diagnosis of ALRI in elderly patients who showed negative initial CR. The patients with negative initial CR had main CT patterns of diffuse bronchial wall thickening, ground-glass opacity, centrilobular nodules, small consolidation or consolidation in the dependent lung on LDCT.