Differentiating COVID-19 CT Manifestations from Other Types of Pneumonia

Abstract

In the early days of COVID-19 pandemic in China, the RT-PCR test reported only 59–71% positive cases among those tested [1, 2]. However, among the patients admitted to the hospitals, there were some patients with typical imaging features of viral pneumonia, but negative test results for RT-PCR tests, even after being tested for several times. The accuracy of nucleic acid RT-PCR test depends on the time of infection, samples and sampling method, quality of the reagent, and different interpretation standards. Thus, RT-PCR tests are often conducted repeatedly if patients have the typical imaging features of pneumonia. The CT manifestations of COVID-19 are mainly that of interstitial pneumonia. The distribution, shape, density, and bronchial and vascular manifestations of lesions are typical, but not specific to COVID-19. Therefore, it is necessary to make differential diagnosis to distinguish COVID-19 from other lung infections with similar CT manifestations, such as pneumonia caused by influenza A (H1N1), avian influenza (H7N9), influenza B, adenovirus, cytomegalovirus, and others (Table 8.1). The application of thoracic CT to COVID-19 diagnosis and imaging assessment of pulmonary infection and damage can add value to clinical management of patients with COVID-19.