Diagnostic Accuracy of North America Expert Consensus Statement on Reporting CT Findings in Patients Suspected of Having COVID-19 Infection: An Italian Single-Center Experience

Abstract

In suspected COVID-19, RT-PCR is the reference standard but has a long reporting time; application of the four standardized categories for CT reporting proposed by RSNA could support a faster triage of patients, in a setting of high community disease burden. Key Points: 1. In this retrospective analysis, categorization of COVID-19 radiological pattern into the four CT categories proposed by RSNA, is strongly predictive of RT-PCR results. 2. In an epidemic setting, "Typical" pattern showed a high Positive Predictive Value for COVID-19 (87.8%), while "atypical" and "negative" pattern a high Positive Predictive Value for non COVID-19 (respectively of 89.6% and 86.2%). 3. "Indeterminate" pattern was mainly observed in elderly patients and is the most challenging category; in this category, the detection of sub-segmental vascular enlargement was most frequently observed in COVID-19 and could be considered as an ancillary sign to guide the diagnostic hypothesis.

Diagnostic Performance of CO-RADS and the RSNA Classification System in Evaluating COVID-19 at Chest CT: A Meta-Analysis

“…For the CO-RADS, substantial to almost perfect interobserver agreement has been reported, with ĸ values of 0.648 to 0.773 ( 8 ) and intraclass correlation coefficients of 0.800 to 0.874 ( 20 ). For the RSNA classification system, moderate to substantial interobserver agreement has been reported, with ĸ values of 0.500 ( 23 ) and of 0.570 to 0.663 ( 8 ). None of the included studies reported data on intraobserver agreement.…”

“…There was no risk of bias with regard to patient selection in the other studies or with regard to index test. Risk of bias with respect to reference test was rated high in three studies ( 23 , 26 , 27 ) because repeated RT-PCR testing was not used in all patients with a negative initial RT-PCR result and persistent clinical suspicion of COVID-19. Risk of bias with respect to reference test was rated unclear in one study ( 21 ), because it was not clear whether all patients with an initial negative RT-PCR result and a persistent clinical suspicion of COVID-19 underwent repeated RT-PCR testing.…”

“…In our current meta-analysis, the "reference standard" was the only QUADAS-2 item which was deemed to be of high risk of bias. This item applied to three of the nine included studies (33%) because repeated RT-PCR testing was not used in all patients with a negative initial RT-PCR result and persistent clinical suspicion of COVID-19 ( 23 , 26 , 27 ).…”

“…Geographical differences, non-reported prevalence of other lung diseases, interobserver variability in chest CT assessment, RT-PCR performance, and some methodological quality issues may have been potential sources of heterogeneity. Note that interobserver agreement varies from substantial to almost perfect for the CO-RADS ( 8 , 20 ) and from moderate to substantial for the RSNA classification system ( 8 , 23 ).…”

COVID-19 Diagnosis in Case of Two Negative Nasopharyngeal Swabs: Association between Chest CT and Bronchoalveolar Lavage Results

“…The Society of Thoracic Radiology/Radiological Society of North America (STR/RSNA) and Prokop et al ( 2 , 3 ) introduced two distinct COVID-19 CT probability scores, here labeled STR/RSNA and COVID-19 Reporting and Data System (CO-RADS). Studies frequently use a single RT-PCR with nasopharyngeal swab as the standard of reference compared with CT ( 4 , 5 ). To our knowledge, no prior study used the more sensitive bronchoalveolar lavage (BAL) as a reference standard for comparison to CT for the diagnosis of COVID-19 infection.…”