High-resolution computed tomography findings from adult patients with Influenza A (H1N1) virus-associated pneumonia

Abstract

Objective The aim of this study was to assess the high-resolution computed tomography (HRCT) findings at presentation in patients diagnosed with Influenza A (H1N1) virus-associated pneumonia. Materials and methods We reviewed the HRCT findings from 20 patients diagnosed with Influenza A (H1N1) and compared their HRCT scans with chest radiographs, obtained on the same day. The imaging studies were obtained 4–9 days after the onset of symptoms. The patients included 11 men and 9 women (ages 24–62 years; mean 42.7 years). All patients had a body temperature greater than 100.4 °F (>38 °C), tachypnea, and cough. Other common symptoms included diarrhea (60%) and sore throat (30%). The radiographs and HRCT scans were reviewed independently by two observers who reached a consensus decision. Results The predominant HRCT findings consisted of bilateral ground-glass opacities ( n = 12), bilateral areas of consolidation ( n = 2), or a mixed bilateral pattern of ground-glass opacities and areas of consolidation ( n = 6). The abnormalities were bilateral in all of the 20 patients, had a predominantly sub-pleural distribution in 13 patients, and had a random distribution in the remaining 7 patients. The predominant radiographic findings were consolidations. Normal radiographs were found in 4 out of the 20 patients. Conclusion HRCT may reveal parenchymal abnormalities in patients with Influenza A (H1N1) infection who have normal findings on radiographs. The predominant HRCT findings were bilateral, peripheral, ground-glass opacities and/or bilateral areas of consolidation. The patients who presented consolidations had more severe clinical course.