CT-sign “ground glass opacity” in granulomatosis with polyangiitis and community-acquired pneumonia

Granulomatosis with polyangiitis (GPA) is a rare systemic disease characterized by two parallel processes: necrotizing granulomatous inflammation and low-immune vasculitis predominantly affecting small vessels. Differential diagnosis of lung lesions on CT in patients with an established diagnosis of granulomatosis with polyangiitis can be very difficult.

Purpose. Developing computed tomography criteria for the differential diagnosis of infiltrative changes in the lungs in patients with GPA and community-acquired bacterial pneumonia.

Materials and methods. 67 CT examinations of the chest by 24 patients with verified GPA with infiltrative lung lesions and 36 CT examinations by 30 patients with bacterial pneumonia without concomitant pulmonary pathology, a comparative analysis of the following characteristics of ground glass opacity symptom was performed: “location", “craniocaudal distribution”, “uniformity”, “localization”, “quantity”, “association with consolidation”, “association with pleural effusion”. CT was performed natively on a Toshiba Aquilion Prime CT scanner according to a standard examination protocol with a slice thickness of 1 mm. Statistical processing of the obtained results was carried out

using the software application RStudio, version 1.3.1093 for mac OS (RStudio, PBC). To study the relationships between two categorical variables, the χ2 independence test and the principal component method for categorical

variables were used.

Results. GPA is characterized by multiple bilateral areas of ground glass opacity compaction, often with a central location, without a statistically significant craniocaudal dependence in the lung regions. In community-acquired pneumonia, this sign is more likely to be unilateral with a peripheral location in the lower lobes of the lung. Statistically significant differences in the degree of homogeneity, combination with consolidation, pleural effusion have not been established.

Conclusion. CT reveals the characteristic features of the ground glass opacity CT sign in GPA and pneumonia, which, together with clinical and laboratory data, increase the accuracy of radiodiagnosis of these diseases.

1. Safonova T.D., Sheikh Z.V. Modern concepts of the prevalence, pathomorphology and diagnosis of granulomatosis with polyangiitis with pulmonary involvement (literature review). Medical Visualization. 2021; 25 (3): 97–108. https://doi.org/10.24835/16070763-981 (In Russian)

2. Koroleva I.M., Chichkova N.V., Sokolina I.A., Buchneva A.V. Granulomatosis with polyangiitis (Wegener's granulomatosis): a variety of clinical and radiological manifestations. Consilium Medicum. 2019; 21 (11): 80–85. https://doi.org/10.26442/20751753.2019.11.190687 (In Russian)

3. Beketova T.V., Frolova N.F., Stolyarevich E.S., Volkov M.Yu., Kotenko O.N., Aleksandrova E.N. Problems in the diagnosis and treatment of ANCA-associated systemic vasculitis: In the focus of ANCA-negative pauci-immune glomerulonephritis. Nauchno-Prakticheskaya Revmatologiya = Rheumatology Science and Practice. 2016; 54 (5): 543–552 https://doi.org/10.14412/19954484-2016-543-552 (In Russian)

4. Demko I.V., Gordeeva N.V., Mamaeva M.G., Matveeva I.V., Kraposhina A.Yu., Soloveva I.A., Sobko E.A., Zeleniy S.V., Loktionova M.M. Difficulties of differential diagnosis in practice of pulmonary medicine: granulomatosis with polyangiitis. RMJ. 2017; 3: 211–213. (In Russian)

5. Sheikh Zh.V., Safonova T.D. Computed tomography in the diagnosis of lung lesions in systemic vasculitis. Practical pulmonology. 2019; 2: 69–74. (In Russian)

6. Masiak A., Fijałkowska J., Nowakowski S. et al. New lung mass in a patient with granulomatosis with polyangiitis. Rheumatol. Int. 2021; 41 (2): 493–499. https://doi.org/10.1007/s00296-020-04646-w

7. Sacoto G., Boukhlal S., Specks U. et al. Lung involvement in ANCA-associated vasculitis. Presse Med. 2020; 49 (3): 104039. https://doi.org/10.1016/j.lpm.2020.104039

8. Schaefer-Prokop C. Pulmonary manifestations of systemic diseases. In: Diseases of the Chest, Breast, Heart and Vessels 2019–2022: Diagnostic and Interventional Imaging / Eds J. Hodler, R.A. Kubik-Huch, G.K. von Schulthess. Springer, 2019. 248 p.

9. Holl-Ulrich K., Reinhold-Keller E., Müller A., Feller A. Pathology of vasculitis: differential diagnosis and selected disorders. Verh. Dtsch. Ges. Path. 2002; 86: 83–90.

10. Ananthakrishnan L., Sharma N., Kanne J.P. Wegener's Granulomatosis in the Chest: High-Resolution CT Findings. Am. J. Roentgenol. 2009; 192 (3): 676–682. https://doi.org/10.2214/AJR.08.1837

11. Li J., Li C., Li J. Thoracic manifestation of Wegener's granulomatosis: Computed tomography findings and analysis of misdiagnosis. Exp. Ther. Med. 2018; 16 (1): 413–419. https://doi.org/10.3892/etm.2018.6154

12. Tee Q.X., Wong A., Nambiar M., Lau, K.K. Granulomatosis with polyangiitis: Common and uncommon presentations. J. Med. Imaging Radiat. Oncol. 2022; 66: 1089–1096. https://doi.org/10.1111/1754-9485.13471

13. Systemic vasculitis: the possibilities of modern medical imaging: Textbook / Zh.V. Sheikh et al. M.: Kraft+, 2019. 172 p. (In Russian)