Abstract:
Background: COVID-19 (coronavirus disease 2019), an ongoing global pandemic is one of the causes of viral pneumonia. It is infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It mainly affects respiratory system resulting in mild symptom to severe respiratory distress. The definitive test for SARS-CoV-2 is the real-time reverse transcriptase-polymerase chain reaction test. Although less sensitive than chest CT, chest radiography is typically the first-line imaging modality used for patients suspected with COVID-
19. Its sensitivity and specificity are variably reported from 31-69% and 60-80% respectively.
Objective: The purpose of this study is to determine sensitivity of chest radiograph in diagnosing Covid-19 pneumonia and associated factors
Methods and materials: Institutional based retrospective cross-sectional study was conducted on 331 COVID-19 suspected patients ( 256 PCR/RDT positive and 75 negative) admitted to Tibebe Ghion specialized Hospital isolation center between June and September 2022 in Bahir Dar, Ethiopia. Structured questionnaire was used to extract patients’ clinical data and CXR imaging findings by assigned residents and principal investigator. Data was entered and analyzed using IBM SPSS version 25. A multivariable logistic regression analysis was performed to assess factors related to sensitivity of chest radiographs. Independent variables having a p value less than 0.05 in the analysis was considered as a significant association.
Result: Sensitivity of CXR in diagnosing COVID-19 pneumonia was 89.8% with positive predictive value of 84.2%. The specificity of CXR was 42.7% with NPV of 55.2%.
There is increased rate of false negative CXR findings in younger age group (18-30yrs), mild disease, early patient presentation and absence of comorbidity. A multivariable logistic regression analysis showed mild disease and younger age group (18-30yrs) to have significant association. The younger age group (18-30yrs) of patients are 5.9 times more likely to have normal (negative) chest radiograph as compared to older age group (>60yrs) [AOR = 5.92, 95% CI (1.8-18.85%)]. Patients with mild disease are 3.8 times more likely to have negative chest radiograph as compared to patients with critical disease [AOR= 3.8, 95% CI (1-15)].
Most common CXR finding was bilateral mid to lower lung field patchy air space opacity with peripheral predominant distribution which was found in 55.4% of COVID-19– positive cases, versus 26% of COVID-19–negative cases. Peripheral patchy airspace opacities and diffuse bilateral lung opacity were also more common in COVID-19–positive cases than test negative cases (21% vs 4%, and 6% vs 2%, respectively).
Conclusion: The result shows that chest radiography can detect COVID-19 infection in symptomatic patients and can be used as alternative diagnostic modality in absence of viral tests. It can also serve as a good screening tool in a busy setting to avoid unnecessary delay.
Key words: Chest radiograph, sensitivity, COVID-19