Pneumonia with Negative Chest X-Ray but Positive CT Scan

Patients who present with suspected pneumonia sometimes undergo both chest x-ray (CXR) and computed tomography (CT). Occasionally, CXR is negative but CT suggests pneumonia. In this study, researchers compared clinical characteristics of CXR-negative, CT-positive patients and patients in whom pneumonia was visualized by both modalities. The data were obtained from a previously published study of patients with community-acquired pneumonia who were admitted to five U.S. hospitals; severely immunosuppressed patients were excluded (NEJM JW Gen Med Sep 1 2015 and N Engl J Med 2015; 373:415).

All 2251 patients underwent CXR, and one third of them also underwent CT. Among the 748 patients who underwent both CXR and CT, 87% had pneumonia on both ima…