Determining the diagnostic accuracy of non contrast HRCT Chest study in COVID-19 Pneumonia Keeping PCR assay as gold standard

Abstract

Objective: To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) chest in determination of corona virus disease (COVID-19) taking polymerase chain reaction (PCR) as gold standard. Methods: This diagnostic cross-sectional study was conducted at Shifa International Hospital Islamabad (SIH) from February 2020 to April 2020. All patients suspected for COVID 19 pneumonia were consecutively enrolled. Diagnosis was done via both HRCT chest and PCR assay. Patient s demographic characteristics and PCR results were retrieved from hospital database. Diagnostic accuracy was explored by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall diagnostic accuracy. Results: Of 250 patients, the mean age was 58.5 years +- 14.7 years. HRCT findings in positive scans showed that of 181 patients, majority of the patients presented with multifocal peripheral rounded ground glass opacities (GGOs) with crazy paving observed in 77 (42.5%), multifocal peripheral rounded in GGOs 51 (28.1%), and multifocal peripheral rounded GGOs with crazy paving and consolidations 45 (24.8%). Furthermore, bilateral lungs and multifocal multilobar involvement of lungs was observed in 179 (98.8%) each. While peripheral lung involvement was observed in 176 (97.2%) patients. The sensitivity, specificity, PPV, NPV, and overall diagnostic accuracy of HRCT chest in diagnosing COVID-19 pneumonia was 93.4%, 53.5%, 71.2%, 86.9%, and 75.6% respectively. Conclusion: HRCT chest has a higher sensitivity and comparable diagnostic accuracy to PCR testing in diagnosing COVID 19 pneumonia and thus in the epidemic areas, it can be used as an important adjunct to PCR testing.