Influenza H1N1 virus-associated pneumonia often resembles rapidly progressive interstitial lung disease seen in collagen vascular diseases and COVID-19 pneumonia; CT-pathologic correlation in 24 patients.

Abstract

PURPOSE:

To describe computed tomography (CT) findings of influenza H1N1 virus-associated pneumonia (IH1N1VAP), and to correlate CT findings to pathological ones.

METHODS:

The study included 24 patients with IH1N1VAP. Two observers independently evaluated the presence, distribution, and extent of CT findings. CT features were divided into either classical form (C-form) or non-classical form (NC-form). C-form included: A.) broncho-bronchiolitis and bronchopneumonia type, whereas NC-forms included: B.) diffuse peribronchovascular type, simulating subacute rheumatoid arthritis-associated (RA) interstitial lung disease (ILD) and C.) lower peripheral and/or peribronchovascular type, resembling dermatomyositis-associated ILD and COVID-19 pneumonia. In 10 cases with IH1N1VAP where lung biopsy was performed, CT and pathology findings were correlated.

RESULTS:

The most common CT findings were ground-glass opacities (24/24, 100 %) and airspace consolidation (23/24, 96 %). C-form was found in 11 (46 %) patients while NC-form in 13 (54 %). Types A, B, and C were seen in 11(46 %), 4 (17 %), and 9 (38 %) patients, respectively. The lung biopsy revealed organizing pneumonia in all patients and 6 patients (60 %) showed incorporated type organizing pneumonia that was common histological findings of rapidly progressive ILD.

CONCLUSION:

In almost half of patients of IH1N1VAP, CT images show NC-form pneumonia pattern resembling either acute or subacute RA or dermatomyositis-associated ILD and COVID-19 pneumonia.

• Authors: Makiko Murota, Takeshi Johkoh, Kyung Soo Lee, Tomas Franquet, Yasuhiro Kondoh, Yoshihiro Nishiyama, Tomonori Tanaka, Hiromitsu Sumikawa, Ryoko Egashira, Norihiko Yamaguchi, Kiminori Fujimoto, Junya Fukuoka, Group of Creation of Radiological Paper from Japan in diffuse lung disease
• Journal: European journal of radiology open (Eur J Radiol Open) Vol. 7 Pg. 100297 ( 2020) ISSN: 2352-0477 [Print] England
• PMID: 33318970 (Publication Type: Journal Article)
• Copyright: © 2020 The Author(s).