Comparison of chest computed tomography findings of RT-PCR negative and RT-PCR positive cases in COVID-19 patients

The purpose was to compare the results of the RT-PCR test, with the findings of Chest CT and to determine the features of CT for the diagnosis of COVID-19 and how to approach RT-PCR negative patients.

Chest CT findings of 569 COVID-19 diagnosed patients, followed up at the pandemic wards between March and June 2020 were retrospectively examined. Patients were grouped according to RT-PCR results, gender, and age.

284 (49%) were RT-PCR(+), 285 (50.8%) were RT-PCR(-) of total 569 patients. 11 (1.9%) of RT-PCR(+) had no involvement in Chest CT while all the RT-PCR(-) patients were CT(+). The distribution of lesions in CT were; 544 (95.6%) bilateral, 553 (97.2%) multilobar, 557(98%) peripherally 151 (26.5%) posteriorly localized. The most common findings were; 539 (94.7%) ground-glass opacity (GGO), 365 (64.1%) consolidation, 160 (28.1%) crazy paving interlobular septal thickening. CO-RADS mean value was 5.4 ± 0.7. GGO and reticulation in RT-PCR(-) patients were 280 (98.2%) and 24 (8.4%); while they were 259 (91.2%) and 12 (4.2%) in RT-PCR(+) patients, were significantly higher (p < 0.05). No significant difference was observed, in CT findings for gender. Only the findings of crazy paving interlobular septal thickening and reticulation in 18-64 age group were significantly higher than that in 65-94 age group, 105 (24.8%)-55 (37.9%), 19 (4.5%)-17 (11.7%) respectively (p < 0.05).

The typical findings of COVID-19 pneumonia in Chest CT are: GGO, consolidation and crazy paving in bilateral, peripheral, posterior localization. CT plays an essential role for diagnosis, isolation and treatment in cases of COVID-19 and RT-PCR negative test should be verified by CT.