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Objectives:To evaluate the contribution of thoracic CT in the diagnosis of patients suspected of having COVID-19 in comparison with the current reference technique (RT-PCR) and to determine the medico-economic impact of COVID-19 in the radiology and medical imaging department of the National Hospital University Center of Fann.

Materials and methods:It was a retrospective, descriptive study over a period of 4 months between April 1 and July 31, 2020, in the radiology department of the CHNU of Fann.

Patients were included if they were clinically suspected of having COVID-19 and had undergone a thoracic CT scan and a nasopharyngeal swab for RT-PCR analysis.

The parameters studied were epidemiological data, clinical data, images suggestive of COVID-19 (ground glass opacities, condensation, reticulations, lesion topography, extent of lesions), the existence or not of pulmonary embolism, abnormalities in favor of superinfection, associated lesions, impact on the rate of attendance of the different modalities, and impact on revenue. The diagnostic performance of CT was calculated with RT-PCR as a reference tool.

Results:In our series the median age was 62 years and the sex ratio 1.61.

Fever was reported in 7 patients (2.23%); cough in 17 patients (5.41%); dyspnea in 30 patients (9.55%) and ARDS in 63 patients (20.07%). The clinic was not specified in 163 patients (51.91%). Chest CT came back normal in 20 patients (6.37%), suggestive of COVID-19 in 274 patients (87.26%) and not suggestive of COVID-19 in 20 patients (6.37%). RT-PCR was positive in 125 patients (39.80%). The sensitivity and specificity of CT were 91.2% and 15.34% respectively, and the PPV, NPV and accuracy rate were 42%, 72.5% and 45.5% respectively. The decrease in attendance was estimated at 59% for standard radiography, 55% for ultrasound, 24% for CT and 87% for mammography. In our study, there was a 40% decrease in revenue in the second quarter of 2020 compared to the first quarter.

Conclusion: Chest CT has a high sensitivity for the diagnosis of COVID-19. As such, it can be considered a primary tool for detecting lung lesions suggestive of COVID-19 pneumonia.

The medico-economic impact of COVID-19 has been significant.


COVID-19, Chest CT, Radiology, Economic impact, Africa

Article Details

Author Biography

Abdoulaye Dione DIOP, Centre Hospitalier National Universitaire de Fann

Nouveau agrégé du dernier concours du CAMES

How to Cite
niang, & DIOP, A. D. (2021). Contribution of chest CT in patients suspected of having COVID-19 and medico-economic impact of the COVID-19 pandemic in the radiology department of Fann (Dakar-Senegal). Journal Africain d’Imagerie Médicale (J Afr Imag Méd)., 13(1).


  1. 1. Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. Jama. 2020;323(13):1239–1242.
  2. 2. Kucharski AJ, Russell TW, Diamond C, Liu Y, Edmunds J, Funk S, et al. Early dynamics of transmission and control of COVID-19: a mathematical modelling study. Lancet Infect Dis. 2020;20(5):553–558.
  3. 3. Fang Y, Zhang H, Xie J, Lin M, Ying L, Pang P, et al. Sensitivity of chest CT for COVID-19: comparison to RT-PCR. Radiology. 2020;200432.
  4. 4. Ai T, Yang Z, Hou H, Zhan C, Chen C, Lv W, et al. Correlation of chest CT and RT-PCR testing in coronavirus disease 2019 (COVID-19) in China: A report of 1014 cases [published online ahead of print February 26, 2020]. Radiology. 10.
  5. 5. Pan F, Ye T, Sun P, Gui S, Liang B, Li L, et al. Time course of lung changes on chest CT during recovery from 2019 novel coronavirus (COVID-19) pneumonia. Radiology. 2020;
  6. 6. Zhou F, Yu T, Du R, Fan G, Liu Y, Liu Z, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. The lancet. 2020;395(10229):1054–1062.
  7. 7. Wu C, Chen X, Cai Y, Zhou X, Xu S, Huang H, et al. Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China. JAMA Intern Med. 2020;180(7):934–943.
  8. 8. Guan W, Ni Z, Hu Y, Liang W, Ou C, He J, et al. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med. 2020;382(18):1708–1720.
  9. 9. Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet Lond Engl. 15 2020;395(10223):497‑506.
  10. 10. Haitao T, Vermunt J, Abeykoon J, Ghamrawi R, Gunaratne M, Jayachandran M, et al. COVID-19 and sex differences: mechanisms and biomarkers. In: Mayo Clinic Proceedings. Elsevier; 2020.
  11. 11. Petrilli CM, Jones SA, Yang J, Rajagopalan H, O’Donnell L, Chernyak Y, et al. Factors associated with hospital admission and critical illness among 5279 people with coronavirus disease 2019 in New York City: prospective cohort study. BMJ [Internet]. 22 mai 2020 [cité 5 mars 2021];369:m1966. Disponible sur:
  12. 12. Bernheim A, Mei X, Huang M, Yang Y, Fayad ZA, Zhang N, et al. Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to Duration of Infection. Radiology [Internet]. 20 févr 2020 [cité 5 mars 2021];295(3):200463. Disponible sur:
  13. 13. Caruso D, Zerunian M, Polici M, Pucciarelli F, Polidori T, Rucci C, et al. Chest CT features of COVID-19 in Rome, Italy. Radiology. 2020;296(2):E79–E85.
  14. 14. Salehi S, Abedi A, Balakrishnan S, Gholamrezanezhad A. Coronavirus Disease 2019 (COVID-19): A Systematic Review of Imaging Findings in 919 Patients. Am J Roentgenol [Internet]. 14 mars 2020 [cité 5 mars 2021];215(1):87‑93. Disponible sur:
  15. 15. Niang I, Diallo I, Diouf JCN, Ly M, Toure MH, Diouf KN, et al. Sorting and detection of COVID-19 by low-dose thoracic CT scan in patients consulting the radiology department of Fann hospital (Dakar-Senegal). Pan Afr Med J. 2020;37(Suppl 1):22–22.
  16. 16. Ye Z, Zhang Y, Wang Y, Huang Z, Song B. Chest CT manifestations of new coronavirus disease 2019 (COVID-19): a pictorial review. Eur Radiol [Internet]. 1 août 2020 [cité 5 mars 2021];30(8):4381‑9. Disponible sur:
  17. 17. Zhao W, Zhong Z, Xie X, Yu Q, Liu J. Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study. Am J Roentgenol [Internet]. 3 mars 2020 [cité 5 mars 2021];214(5):1072‑7. Disponible sur:
  18. 18. Falaschi Z, Danna PSC, Arioli R, Pasché A, Zagaria D, Percivale I, et al. Chest CT accuracy in diagnosing COVID-19 during the peak of the Italian epidemic: A retrospective correlation with RT-PCR testing and analysis of discordant cases. Eur J Radiol [Internet]. 1 sept 2020 [cité 5 mars 2021];130:109192. Disponible sur:
  19. 19. Wang Y, Dong C, Hu Y, Li C, Ren Q, Zhang X, et al. Temporal changes of CT findings in 90 patients with COVID-19 pneumonia: a longitudinal study. Radiology. 2020;200843.
  20. 20. Jiang Y, Guo D, Li C, Chen T, Li R. High-resolution CT features of the COVID-19 infection in Nanchong City: Initial and follow-up changes among different clinical types. Radiol Infect Dis [Internet]. 1 juin 2020 [cité 5 mars 2021];7(2):71‑7. Disponible sur:
  21. 21. Iba T, Levy JH, Connors JM, Warkentin TE, Thachil J, Levi M. The unique characteristics of COVID-19 coagulopathy. Crit Care Lond Engl. 18 juin 2020;24(1):360.
  22. 22. Grillet F, Behr J, Calame P, Aubry S, Delabrousse E. Acute Pulmonary Embolism Associated with COVID-19 Pneumonia Detected with Pulmonary CT Angiography. Radiology [Internet]. 23 avr 2020 [cité 6 mars 2021];296(3):E186‑8. Disponible sur:
  23. 23. Mestre-Gómez B, Lorente-Ramos RM, Rogado J, Franco-Moreno A, Obispo B, Salazar-Chiriboga D, et al. Incidence of pulmonary embolism in non-critically ill COVID-19 patients. Predicting factors for a challenging diagnosis. J Thromb Thrombolysis [Internet]. 1 janv 2021 [cité 6 mars 2021];51(1):40‑6. Disponible sur:
  24. 24. Li K, Wu J, Wu F, Guo D, Chen L, Fang Z, et al. The Clinical and Chest CT Features Associated With Severe and Critical COVID-19 Pneumonia. Invest Radiol [Internet]. 2020 [cité 6 mars 2021]; Disponible sur:
  25. 25. La société d’Imagerie Thoracique propose un compte-rendu structuré de scanner thoracique pour les patients suspects de COVID-19 [Internet]. SFR e-Bulletin. 2020 [cité 9 mars 2021]. Disponible sur:
  26. 26. Grasselli G, Zangrillo A, Zanella A, Antonelli M, Cabrini L, Castelli A, et al. Baseline Characteristics and Outcomes of 1591 Patients Infected With SARS-CoV-2 Admitted to ICUs of the Lombardy Region, Italy. JAMA [Internet]. 28 avr 2020 [cité 5 mars 2021];323(16):1574‑81. Disponible sur:
  27. 27. Corman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Eurosurveillance. 2020;25(3):2000045.
  28. 28. Wang W, Xu Y, Gao R, Lu R, Han K, Wu G, et al. Detection of SARS-CoV-2 in different types of clinical specimens. Jama. 2020;323(18):1843–1844.
  29. 29. Long C, Xu H, Shen Q, Zhang X, Fan B, Wang C, et al. Diagnosis of the Coronavirus disease (COVID-19): rRT-PCR or CT? Eur J Radiol [Internet]. 1 mai 2020 [cité 27 juin 2020];126:108961. Disponible sur:
  30. 30. Coronavirus COVID 19 : au CHU de Clermont-Ferrand, le rôle crucial de l’imagerie médicale [Internet]. France 3 Auvergne-Rhône-Alpes. [cité 6 mars 2021]. Disponible sur:
  31. 31. Cavallo JJ, Forman HP. The economic impact of the COVID-19 pandemic on radiology practices. Radiology. 2020;296(3):E141–E144.