For the management of patients referred to respiratory triage during the early stages of the SARS-CoV-2 pandemic, either chest radiograph (CXR) or computed tomography (CT) were used as first-line diagnostic tools. The aim of this study was to compare the impact on triage, diagnosis and prognosis of patients with suspected COVID-19 when clinical decisions are derived from reconstructed CXR or from CT.
We reconstructed CXR (r-CXR) from high-resolution CT (HRCT) scan. Five clinical observers independently reviewed clinical charts of 300 subjects with suspected COVID-19 pneumonia, integrated with either r-CXR or HRCT report in two consecutive blinded and randomised sessions: clinical decisions were recorded for each session. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and prognostic value were compared between r-CXR and HRCT. The best radiological integration was also examined to develop an optimised respiratory triage algorithm.
Interobserver agreement was fair (Kendall's W=0.365; p<0.001) by r-CXR-based protocol and good (Kendall's W=0.654; p<0.001) by CT-based protocol. NPV assisted by r-CXR (31.4%) was lower than that of HRCT (77.9%). In case of indeterminate or typical radiological appearence for COVID-19 pneumonia, extent of disease on r-CXR or HRCT were the only two imaging variables that were similarly linked to mortality by adjusted multivariable models
The present findings suggest that clinical triage is safely assisted by CXR. An integrated algorithm using first-line CXR and contingent use of HRCT can help optimise management and prognostication of COVID-19.