To assess the diagnostic and prognostic ability of CXRs in COVID-19 pneumonitis

Abstract

Rationale: The COVID-19 pandemic has led to the deaths of millions with its ability to cause severe pneumonia. Diagnosis is based on PCR testing which has many limitations: lengthy turnaround times, lack of universal availability and variance in sensitivity. Imaging such as CXR could be a valuable and faster aid in diagnosing COVID-19 compared to PCR. It is widely available, cheap and can be performed at the bedside- enabling a rapid turnover of patients whilst minimising cross-link infection. However only a few studies have assessed its prognostic value. ^[1]

We aim to analyse the diagnostic accuracy of CXR in COVID-19 and to assess if severity of COVID pneumonitis on CXR correlated with mortality.

Methods: A retrospective study of all in-patients aged ≥ 18 years with a confirmed diagnosis of COVID-19 during the first and second waves of the pandemic. Admission CXRs and in-patient CT Thorax scans were analysed. Statistical analysis was performed using the Chi-Squared Test for independence.

Results: 999 COVID-19 patients were included in the study. Severity of COVID pneumonitis on CXR correlated with mortality when patients were grouped into the following categories: normal (n=161, mortality=42%), mild (n=220, mortality=33%) moderate, (n=328, mortality=42%) and severe (n=290, mortality=58%) (P<0.001).

251 patients had both CT and CXRs. CT scans were superior in diagnosing COVID pneumonitis (63%) compared to CXR (47%) (P<0.001).

Conclusion: Our study showed a positive correlation between the severity of COVID pneumonitis on CXR and mortality, supporting the use of CXR in the ED to help rapidly identify and treat patients at high risk of death.

References:

1. Balbi, M. et al. Eur Radiol 2020;31:1999-2012