A comparative study of thin-section CT findings between seasonal influenza virus pneumonia and Streptococcus pneumoniae pneumonia

Abstract

Objective: To compare the pulmonary thin-section CT findings in patients with seasonal influenza virus pneumonia with Streptococcus pneumoniae pneumonia.

Methods: The study group included 30 patients (20 males and 10 females; age range, 20-91 years; mean age, 55.9 years) with seasonal influenza virus pneumonia and 71 patients (47 males and 24 females; age range, 27-92 years; mean age, 67.5 years) with S. pneumoniae pneumonia.

Results: The proportion of community-acquired infection was significantly higher in patients with influenza virus pneumonia than with S. pneumoniae pneumonia (p = 0.001). CT findings of ground-glass attenuation (GGA) (p = 0.012) and crazy-paving appearance (p = 0.03) were significantly more frequent in patients with influenza virus pneumonia than with S. pneumoniae pneumonia. Conversely, consolidation (p < 0.001), mucoid impaction (p < 0.001), centrilobular nodules (p = 0.04) and pleural effusion (p = 0.003) were significantly more frequent in patients with S. pneumoniae pneumonia than in those with influenza virus pneumonia.

Conclusion: Pulmonary thin-section CT findings, such as consolidation and mucoid impaction may be useful in distinguishing between seasonal influenza virus pneumonia and S. pneumoniae pneumonia.

Advances in knowledge: (1) Distinguishing seasonal influenza virus pneumonia with S. pneumoniae pneumonia is important. (2) The CT findings of GGA and crazy-paving appearance were more frequently found in patients with influenza virus pneumonia than in patients with S. pneumoniae pneumonia, whereas consolidation, mucoid impaction, centrilobular nodules and pleural effusion were more frequently found in patients with S. pneumoniae pneumonia.

Figure 1.

Pneumonia caused by seasonal influenza virus (Type A) in a 41-year-old male, 1 day after the onset of cough and fever. Transverse CT image (1-mm thickness) of the right upper lobe shows ground-glass attenuation and bronchial wall thickening (arrows).

Figure 2.

Pneumonia caused by influenza virus (Type A) in a 59-year-old male, 1 day after the onset of cough and fever. Transverse CT image (1-mm thickness) of the level of the left B3 division shows ground-glass attenuation, crazy-paving appearance and bronchial wall thickening (arrow).

Figure 3.

Pneumonia caused by Streptococcus pneumoniae in a 61-year-old male, 4 days after the onset of fever, cough with sputum and dyspnoea. Transverse CT image (1-mm thickness) at the level of the tracheal carina shows consolidation, ground-glass attenuation and crazy-paving appearance. Interlobular septal thickening is also present (arrow).

Figure 4.

Pneumonia caused by Streptococcus pneumoniae in a 68-year-old male, 5 days after the onset of cough with sputum and fever. Transverse CT image (1-mm thickness) of the left lower lobe shows consolidation, ground-glass attenuation, centrilobular nodules (arrowheads) and mucoid impaction (arrows).

Figure 5.

Pneumonia caused by Streptococcus pneumoniae in a 52-year-old male, 3 days after the onset of cough with sputum and fever. Transverse CT image (1-mm thickness) of right lower lobe shows bronchial wall thickening, mucoid impaction (arrowheads) and centrilobular nodules (arrows).