Aim: The aim of this study was to evaluate retrospectively the chest computed tomography findings of influenza A (H1N1) pneumonia and their relationship with clinical outcome.
Methods: Chest computed tomography findings and clinical outcomes of 76 patients with influenza A (H1N1) pneumonia were assessed. Computed tomography findings were evaluated for the presence and distribution of parenchymal abnormalities, which were then classified into 3 patterns: bronchopneumonia, cryptogenic organizing pneumonia (COP), and acute interstitial pneumonia (AIP) patterns. Clinical courses were divided into 2 groups on the basis of necessitating admission to intensive care unit or mechanical ventilation therapy (group 1) or not (group 2).
Results: Lung abnormalities consisted of ground-glass opacity (93%, 71 patients), consolidation (66%, 50 patients), small nodules (61%, 46 patients), and tree-in-bud sign (22%, 17 patients). Lesions were classified into bronchopneumonia (49%, 37 patients), COP (30%, 23 patients), AIP (18%, 14 patients), and unclassifiable (3%, 2 patients) patterns. Patients with AIP pattern had a tendency to belonging to group 1, accounting for 40% (8 of 20 patients) of group 1 course and only 11% (6 of 56 patients) of group 2 course (P = 0.004).
Conclusions: Computed tomography findings of influenza A (H1N1) pneumonia in adults can be classified into COP, AIP, and bronchopneumonia patterns. Patients presenting with AIP pattern have a tendency to show poor prognosis.
From the *Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul; †Department of Radiology, Pusan National University Hospital, Pusan National University School of Medicine and Medial Research Institute, Pusan; and ‡Department of Radiology, Pusan National University Yangsan Hospital, Yangsan, South Korea
Received for publication January 19, 2012; accepted March 13, 2012.
Reprints: Kyung Soo Lee, MD, Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-Dong, Kangnam-Ku, Seoul 135-710, Korea (e-mail: firstname.lastname@example.org).
The authors report no conflicts of interest.