1434. A Characteristic Chest Radiographic Pattern in the Setting of COVID-19 Pandemic
Authors * Denotes Presenting Author
  1. John-Paul Grenier *; Louisiana State University Health Sciences Center
  2. Bradley Spieler; Louisiana State University Health Sciences Center
  3. David Smith; Louisiana State University Health Sciences Center
To determine the utility of the chest radiograph in aiding clinical diagnosis of COVID-19, utilizing RT-PCR as the standard of comparison.

Materials and Methods:
A retrospective study was performed of persons under investigation (PUIs) for COVID-19 presenting to our institution during the exponential growth phase of the COVID-19 outbreak in New Orleans, USA (March 13 – 25, 2020). 376 in-hospital CXR exams for 366 individual patients were reviewed along with concurrent RT-PCR tests. Two experienced radiologists categorized each CXR as characteristic, nonspecific, or negative in appearance for COVID-19, utilizing well-documented COVID-19 imaging patterns. CXR categorization was compared against RT-PCR results to determine the utility of CXR in diagnosing COVID-19.

There were 178/366 male (49%) and 188/366 female (51%) patients with a mean age of 52.7 years (range 17 to 98 years). 37/376 CXR exams (10%) exhibited the characteristic COVID-19 appearance; 215/376 (57%) exhibited the nonspecific appearance; and 124/376 (33%) were considered negative for a pulmonary abnormality. Of the 376 RT-PCR tests evaluated, 200/376 (53%) were positive and 176/376 (47%) were negative. RT-PCR tests took an average of 2.5 ± 0.7 days to result. Sensitivity and specificity for correctly identifying COVID-19 with a characteristic CXR pattern were 15.5% (31/200) and 96.6% (170/176), with PPV and NPV 83.8% (31/37) and 50.1% (170/339), respectively.

The chest radiograph, while low in sensitivity, can be highly suggestive of COVID-19 in patients whose radiographs exhibit characteristic COVID-19 findings, when used in concert with clinical factors in the pandemic setting. While not a substitute for RT-PCR or Chest CT, CXR could provide rapid, cost-effective diagnosis of COVID-19 in a subset of infected patients (estimated at 15.5 out of 100 in our cohort), during the COVID-19 pandemic. The utility of this technique is described in the context of known disadvantages of RT-PCR, considered the gold standard in COVID-19 diagnosis, and Chest CT, which is currently not recommended for COVID-19 diagnosis.