Coronavirus Disease 2019 (COVID-19) in Italy: Double Reading of Chest CT Examination

Abstract

To assess the performance of the second reading of chest compute tomography (CT) examinations by expert radiologists in patients with discordance between the reverse transcription real-time fluorescence polymerase chain reaction (RT-PCR) test for COVID-19 viral pneumonia and the CT report. Three hundred and seventy-eight patients were included in this retrospective study (121 women and 257 men; 71 years median age, with a range of 29-93 years) and subjected to RT-PCR tests for suspicious COVID-19 infection. All patients were subjected to CT examination in order to evaluate the pulmonary disease involvement by COVID-19. CT images were reviewed first by two radiologists who identified COVID-19 typical CT patterns and then reanalyzed by another two radiologists using a CT structured report for COVID-19 diagnosis. Weighted к values were used to evaluate the inter-reader agreement. The median temporal window between RT-PCRs execution and CT scan was zero days with a range of (-9,11) days. The RT-PCR test was positive in 328/378 (86.8%). Discordance between RT-PCR and CT findings for viral pneumonia was revealed in 60 cases. The second reading changed the CT diagnosis in 16/60 (26.7%) cases contributing to an increase the concordance with the RT-PCR. Among these 60 cases, eight were false negative with positive RT-PCR, and 36 were false positive with negative RT-PCR. Sensitivity, specificity, positive predictive value and negative predictive value of CT were respectively of 97.3%, 53.8%, 89.0%, and 88.4%. Double reading of CT scans and expert second readers could increase the diagnostic confidence of radiological interpretation in COVID-19 patients.

Keywords: COVID-19; chest CT; double reading; radiological signs; structured report.

Figure 1

Schematic diagram of patients with discordant findings between RT-PCR test and CT.

Figure 2

CT examination of a patient with clinical suspicion of COVID-19 infection and negative RT-PCR test. The CT images show the presence of GGO areas with typical roundish morphology and a predominantly peripheral distribution, a suspect picture for COVID-19 infection. The second RT-PCR test showed positive results.

Figure 3

Patients with a positive RT-PCR test for COVID-19 infection. The CT exams detected areas of GGO and parenchymal consolidation with multifocal diffuse (a) or predominantly peripheral distribution (b).

Figure 4

CT examination of a patient with a positive RT-PCR test for COVID-19 infection. The same CT shows a single localization of GGO in the right lower lobe with a rounded morphology.

Figure 5

The CT images show a typical aspect of bilateral extended crazy paving characterized by GGO with septal thickening, patchy distribution, and aerial bronchogram.