Abstract
RT-PCR is the gold standard in the diagnosis of COVID-19 infections, due to its high specificity. However, there are clinical situations in which chest CT may prove vital, for example in patients with high clinical and epidemiologic suspicion towards COVID-19 before positive RT-PCR conversion or in detecting complications. Researchers have developed scales that, based on the findings in chest CT, help predict the severity of the disease.
There are three main pathologic patterns of lung injury that correlate with the duration of COVID-19 symptoms. Epithelial pattern with diffuse alveolar damage and desquamation/reactive hyperplasia of pneumocytes; vascular pattern with capillary congestion and (micro)thrombi and fibrotic pattern with interstitial fibrous changes. The epithelial pattern and vascular pattern appear early, even before the symptoms of the disease, whereas the fibrous pattern appears approximately three weeks after the onset of the disease.
Typical findings on chest CT in COVID-19 infection are: GGO, consolidation, GGO mixed with consolidation, interlobular septal thickening, air bronchogram sign, crazy paving, bronchial wall thickening and vascular enlargement.
Findings that may suggest a different etiology include multiple nodules, tree-in-bud opacities, bronchiectasis, pleural and pericardial effusion, extensive consolidations.
References
2. Joseph V. Waller, Parveer Kaur, Amy Tucker, et al., Diagnostic Tools for Coronavirus Disease (COVID-19): Comparing CT and RT-PCR Viral Nucleic Acid Testing, AJR Am J Roentgenol., 2020 Oct;215(4):834-838, doi: 10.2214/AJR.20.23418
3. C Jalaber, T Lapotre, T Morcet-Delattre , et al., Chest CT in COVID-19 pneumonia: A review of current knowledge, Diagn Interv Imaging, Jul-Aug 2020;101(7-8):431-437, doi:10.1016/j.diii.2020.06.001
4. Mingzhi Li, Pinggui Lei, Bingliang Zeng, et al., Coronavirus Disease (COVID-19): Spectrum of CT Findings and Temporal Progression of the Disease, Acad Radiol., 2020 May;27(5):603-608,
doi: 10.1016/j.acra.2020.03.003
5. Marina Carotti, Fausto Salaffi, Piercarlo Sarzi-Puttini, et al., Chest CT features of coronavirus disease 2019 (COVID-19) pneumonia: key points for radiologists, Radiol Med., 2020 Jul;125(7):636-646,doi: 10.1007/s11547-020-01237-4
6. Sana Salehi, Aidin Abedi, Sudheer Balakrishnan and Ali Gholamrezanezhad,Coronavirus Disease 2019 (COVID-19): A Systematic Review of Imaging Findings in 919 Patients,AJR Am J Roentgenol., 2020 Jul;215(1):87-93, doi: 10.2214/AJR.20.23034
7. Yicheng Fang, Huangqi Zhang, Jicheng Xie , et al., Sensitivity of Chest CT for COVID-19: Comparison to RT-PCR,Radiology, 2020 Aug;296(2):E115-E117, doi: 10.1148/radiol.2020200432
8. Xingzhi Xie, Zheng Zhong, Wei Zhao, et al., Chest CT for Typical Coronavirus Disease 2019 (COVID-19) Pneumonia: Relationship to Negative RT-PCR Testing, Radiology, 2020 Aug; 296(2):E41-E45, doi: 10.1148/radiol.2020200343
9. Eleonora Carlicchi, Pietro Gemma, Antonio Poerio, et al., Chest-CT mimics of COVID-19 pneumonia-a review article, Emerg Radiol., 2021 Mar 1;1-12. ,doi: 10.1007/s10140-021-01919-0
10. Adam Bernheim, Xueyan Mei, Mingqian Huang, et al., Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to Duration of Infection,Radiology,
2020 Jun; 295(3):200463, doi: 10.1148/radiol.2020200463
11. Wasilewski PG, Mruk B, Mazur S, Półtorak-Szymczak G, Sklinda K, Walecki J. COVID-19 severity scoring systems in radiological imaging - a review. Pol J Radiol. 2020;85:e361-e368. Published 2020 Jul 17. doi:10.5114/pjr.2020.98009
12. Polak, S.B., Van Gool, I.C., Cohen, D. et al. A systematic review of pathological findings in COVID-19: a pathophysiological timeline and possible mechanisms of disease progression. Mod Pathol 33, 2128–2138 (2020). doi.org/10.1038/s41379-020-0603-3
13. Li X, Zeng X, Liu B, Yu Y. COVID-19 Infection Presenting with CT Halo Sign. Radiol Cardiothorac Imaging. 2020 Feb 12;2(1):e200026. doi: 10.1148/ryct.2020200026. PMID: 33778543; PMCID: PMC7194018.
14. Kim SJ, Lee KS, Ryu YH, Yoon YC, Choe KO, Kim TS, Sung KJ. Reversed halo sign on high-resolution CT of cryptogenic organizing pneumonia: diagnostic implications. AJR Am J Roentgenol. 2003 May;180(5):1251-4. doi: 10.2214/ajr.180.5.1801251. PMID: 12704033.
15. Valette X, du Cheyron D, Goursaud S. Mediastinal lymphadenopathy in patients with severe COVID-19. Lancet Infect Dis. 2020 Nov;20(11):1230. doi: 10.1016/S1473-3099(20)30310-8. Epub 2020 Apr 21. PMID: 32330440; PMCID: PMC7173806.
16. Walecki J, Sklinda K, Mruk B, et al., Chest Computed Tomography (CT) as a Predictor of Clinical Course in Coronavirus Disease ,Med Sci Monit 2021; DOI: 10.12659/MSM.931285
17. Walecki J, Sklinda K, Mruk B, et al., Chest Computed Tomography (CT) Severity Scales in COVID-19 Disease: A Validation Study, Med Sci Monit 2021; DOI: 10.12659/MSM.931283
18. Jędrusik P, Gaciong Z, Sklinda K, et al. Diagnostic role of chest computed tomography in coronavirus disease 2019. Pol Arch Intern Med. 2020; 130: 520-528. doi:10.20452/pamw.15348
19. Harahwa, Tinotenda A., Lai Yau, Thomas Ho, Lim-Cooke, Mae-Sing, Al-Haddi, Salah, Zeinah, Mohamed and Harky, Amer. "The optimal diagnostic methods for COVID-19" Diagnosis, vol. 7, no. 4, 2020, pp. 349-356. https://doi.org/10.1515/dx-2020-0058.
This work is licensed under a Creative Commons Attribution 4.0 International License.