StatementChest x-ray abnormalities in COVID-19 mirror those of CT, demonstrating bilateral peripheral consolidation. Chest x-ray findings have a lower sensitivity than initial RT-PCR testing (69% versus 91%, respectively).
Key Results In a cohort of patients with COVID-19 infection and imaging follow-up, baseline chestx-ray had a sensitivity of 69%, compared to 91% for initial RT-PCR. Chest x-ray abnormalities preceded positive RT-PCR in 6/64 (9%) patients. Common chest x-ray findings mirror those previously described for CT: bilateral, peripheral, consolidation and/or ground glass opacities.
I n P r e s sBackground Current COVID-19 radiological literature is dominated by CT and a detailed description of chest x-ray (CXR) appearances in relation to the disease time course is lacking.
PurposeTo describe the time course and severity of the CXR findings of COVID-19 and correlate these with real time reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-Cov-2 nucleic acid.
Materials and MethodsRetrospective study of COVID-19 patients with RT-PCR confirmation and CXRs admitted across 4 hospitals evaluated between January and March 2020. Baseline and serial CXRs (total 255 CXRs) were reviewed along with RT-PCRs. Correlation with concurrent CTs (total 28 CTs) was made when available. Two radiologists scored each CXR in consensus for: consolidation, ground glass opacity (GGO), location and pleural fluid. A severity index was determined for each lung. The lung scores were summed to produce the final severity score.
ResultsThere were 64 patients (26 men, mean age 5619 years). Of these, 58, 44 and 38 patients had positive initial RT-PCR (91%, [CI: 81-96%]), abnormal baseline CXR (69%, [CI: 56-80%]) and positive initial RT-PCR with abnormal baseline CXR (59 [CI:46-71%]) respectively. Six patients (9%) showed CXR abnormalities before eventually testing positive on RT-PCR. Sensitivity of initial RT-PCR (91% [95% CI: 83-97%]) was higher than baseline CXR (69% [95% CI: 56-80%]) (p = 0.009). Radiographic (mean 6 5 days) and virologic recovery (mean 8 6 days) were not significantly different (p= 0.33). Consolidation was the most common finding (30/64, 47%), followed by GGO (21/64, 33%). CXR abnormalities had a peripheral (26/64, 41%) and lower zone distribution (32/64, 50%) with bilateral involvement (32/64, 50%). Pleural effusion was uncommon (2/64, 3%). The severity of CXR findings peaked at 10-12 days from the date of symptom onset.
ConclusionChest x-ray findings in COVID-19 patients frequently showed bilateral lower zone consolidation which peaked at 10-12 days from symptom onset.
Abbreviations:RT-PCR -reverse transcriptase polymerase chain reaction, GGO-ground glass opacity