Clinical usefulness of tomographic standards for covid-19 pneumonia diagnosis : experience from a Brazilian reference center

Background: COVID-19 is a new disease and the most common complication is pneumonia.The Radiological Society of North America (RSNA) proposed an expert consensus for imagingclassification for COVID-19 pneumonia.Objective: To evaluate sensitivity, specificity, accuracy, and reproducibility of chest CT stan-dards in the beginning of the Brazilian COVID-19 outbreak.Methods: Cross-sectional study performed from March 1st to April 14th, 2020. Patients withsuspected COVID-19 pneumonia submitted to RT-PCR test and chest computed tomography(CT) were included. Tw o thoracic radiologists blinded for RT-PCR and clinical and laboratoryresults classified every patient scan according to the RSNA expert consensus. A third thoracicradiologist also evaluated in case of discordance, and consensus was reached among thethree radiologists. A typical appearance was considered a positive chest CT for COVID-19pneumonia. Sensitivity, specificity, positive and negative predictive values were calculated.Cohen’s kappa coefficient was used to evaluate intra- and inter-rater agreements.Results: A total of 159 patients were included (mean age 57.9 ± 18.0 years; 88 [55.3%] males):86 (54.1%) COVID-19 and 73 (45.9%) non-COVID-19 patients. Eighty (50.3%) patients had apositive CT for COVID-19 pneumonia. Sensitivity and specificity of typical appearance were88.3% (95%CI, 79.9–93.5) and 94.5% (95%CI, 86.7–97.8), respectively. Intra- and inter-rateragreement were assessed (Cohen’s kappa = 0.924, P = 0.06; Cohen’s kappa=0.772, P = 0.05,respectively)