Accuracy of Noncontrast Chest Computed Tomography in COVID‑19 Infection: An Observational and Retrospective Study

Abstract

Objective: During the novel coronavirus pandemic, great challenges are becoming prominent, such as early and rapid diagnoses using simpleand readily available tests. Chest computed tomography (CT) scan plays a major role in the diagnosis and monitoring of the complicationswith high specificity. The purpose of this study is to assess the accuracy of nonenhanced chest CT scan in the diagnosis of coronavirus disease2019 (COVID‑19) disease in suspected patients. Materials and Methods: Eighty four suspected patients were included in this retrospectivestudy from March 1, 2020, to April 1, 2020, who underwent both nonenhanced chest CT scan and real‑time polymerase chain reaction (PCR)test for COVID‑19 disease. Results: The total number of initial reverse transcriptase (RT)‑PCR‑positive results was 52 (61.9%) patients andthat of negative results was 32 (38%) patients. Out of the total number of positive RT‑PCR tests, only fifty (96%) patients showed positiveCT findings. Of the total number of negative RT‑PCR tests (32 [38%] patients), only 8 (25%) patients showed negative CT results. WithRT‑PCR results as the reference standard, the sensitivity, specificity, and the accuracy of chest CT in indicating the COVID‑19 infection were96.15%, 25%, and 69.04%, respectively. Ground‑glass opacity (GGO) was seen in all positive CT patients (74 [100%]), mixed GGO wasseen in 27 (36.4%) patients, and consolidation was seen in 36 (48.6%) patients which was subsegmental in 28 (37.8%) patients. Vasculardilatation sign was seen in 61 (82.4%) patients, crazy paving sign was seen in 31 (41.9%) patients, reverse halo signs were seen in 23 (31%)patients, and air bronchogram was seen in 39 (52.7%) patients. Conclusions: Highly characteristic and specific bilateral multifocal GGOswere reported as the classical/typical chest CT features of COVID‑19 infection with high confidence rate, although it may vary in differentpatients’ parameters and stages so that chest CT imaging has very high sensitivity (96.15%) for the diagnosis of COVID‑19 in epidemic areaswith high pretest probability for disease, and it is recommended to be included as a decision‑making diagnostic test in suspected patients withRT‑PCR‑negative results.