CT-morphological characterization of respiratory syncytial virus (RSV) pneumonia in immune-compromised adults

Characterization and follow-up evaluation of chest CT of RSV pneumonia in immune-compromised adults during a seasonal epidemic.

Retrospective analysis of 132 chest CT examinations of 51 adult immune-compromised patients (29 m/22f, Ø58 years) with clinical signs of pneumonia and positive RSV test in winter 2011/2012. Two experienced chest radiologists evaluated the morphology (bronchial wall thickening, tree-in-bud, nodules, halo, ground-glass opacities, consolidations, pleural fluid) of the CT scans by consensus.

Pathological findings were in 86 % of the chest CT scans: Areas of ground-glass attenuation in 64 %, consolidations in 56 %, nodules in 55 % (Ø 8 mm in maximal diameter, with halo in 71 %), pleural fluid in 44 % (Ø 2 cm), tree-in-bud in 36 %, bronchial wall thickening in 27 % and more than one morphological finding in 72 %. There were no pathological CT findings in 14 % of patients with clinical symptoms of pneumonia because these patients did not undergo follow-up. Radiological progression was found in 45 % of patients and regression in 33 % in follow-up examinations. In 37 % an additional examination of the paranasal sinuses was performed and showed sinusitis in 63 % of cases. 90 % of the patients had sinusitis as well as pneumonia. In addition to RSV, a further pathogenic agent was found in bronchoalveolar lavage of five patients (Aspergillus spec., herpes simplex virus, Pseudomonas aeruginosa).

The most characteristic signs in chest CT scans were at the beginning of pneumonia with nodules and tree-in-bud often combined with bronchial wall thickening. The following CT scans showed characteristic but not pathognomonic chest CT findings of RSV pneumonia. These morphological findings should be recognized seasonally (winter) especially at the beginning of the case of pneumonia. RSV-associated additional sinusitis is probably common and should be noticed.