Ancillary findings on high resolution CT chest associated with typical features of COVID-19 pneumonia (Observational descriptive study at a tertiary care hospital).

OBJECTIVE: To determine the frequency of ancillary pulmonary signs and their relation to the severity of disease seen on high-resolution computed tomography of chest in patients of coronavirus disease-2019 pneumonia. METHODS: The observational descriptive study was conducted at the Armed Forces Institute of Radiology and Imaging, Rawalpindi, Pakistan, from March to July 2020, and included in place of comprised all coronavirus disease-2019 patients who were found positive on reverse transcription-polymerase chain reaction-and were referred to have high-resolution computed tomography of chest. Ancillary pulmonary findings in addition to typical features of coronavirus disease-2019 pneumonia were recorded. These included vacuole sign, halo sign, reverse halo sign, subpleural white line, subpleural translucent line, microvascular dilatation, fibrotic streaks and bronchiectasis. Relative frequency of these signs were determined for mild versus and severe disease, as determined by the computed tomography severity score. Data was analysed using SPSS 26. RESULTS: Of the 1645 patients, 1286(78.2%) were males and 359(21.8%) were females. The overall mean age was 47.5±15.7 years (range: 1-92). High-resolution computed tomography was normal in 418(25.4%) patients, typical findings for coronavirus disease-2019 were seen in 1110(67.5%), indeterminate in 113(16.9%) and atypical in 4(0.2%). Vacuole sign, subpleural white line, subpleural translucent sign, microvascular dilatation and fibrotic streaks were more commonly seen in severe disease (p<0.001), while discrete pulmonary nodule was identified more in the milder form (p<0.05). Halo and reverse halo signs as well as bronchiectatic changes demonstrated no significant propensity to the degree of disease severity (p>0.05). CONCLUSIONS: Coronavirus disease-2019 pneumonia demonstrated various ancillary pulmonary features on high resolution computed tomography of the chest in addition to typical findings more commonly described; radiologists should be aware of these signs and their relation to disease severity.

Chest CT Severity Score as an Auxiliary Grading Tool to COVID-19 Pneumonia Imaging Classification: A Tertiary Care Experience in Pakistan.

OBJECTIVE:   To identify utility of chest computed tomography severity score (CT-SS) as an additional tool to COVID-19 pneumonia imaging classification in assessing severity of COVID-19. STUDY DESIGN: Descriptive analytical study Place and Duration of Study: Armed Forces Institute of Radiology and Imaging, (AFIRI) Rawalpindi, from April 2020 to June 2020. METHODOLOGY: Five hundred suspected COVID-19 cases referred for high resolution computed tomography - chest were included in the study. Cases were categorised by radiological findings using COVID-19 pneumonia imaging classification, proposed in the radiological society of North America expert consensus statement on reporting chest CT findings related to COVID-19. CT-SS was calculated for all scans. Patients were clinically classified according to disease severity as per 'Diagnosis And Treatment Program of Pneumonia of New Coronavirus Infection' recommended by China's National Health Commission. The relationships between radiological findings, CT-SS, and clinical severity were explored. RESULTS: Based on the radiological findings, 298 cases were graded as typical, 34 as indeterminate, 15 as atypical, and 153 as negative for pneumonia. The apical and posterior basal segments of lower lobes were most commonly involved. The CT-SS showed higher values in patients of severe group as compared to those in moderate group (p < 0.05). CT-SS threshold for recognising severe COVID-19 was 18.5 (area under curve, 0.960), with 84.3% sensitivity and 92.5% specificity. CONCLUSION: In coherence with COVID-19 pneumonia imaging classification, CT-SS may provide a comprehensive and objective assessment of COVID-19 severity. Key Words: COVID-19, COVID-19 pneumonia, CT-SS, High resolution computed tomography.