INTRODUCTION
According to the latest guidelines for diagnosis and treatment of
COVID-19(Novel coronavirus pneumonia) by the General Office of the
National Health Commission of China, the use of fluorescent
RT-PCR(reverse transcriptase polymerase chain reaction) to detect
nucleic acids of the coronavirus is the gold standard for molecular
diagnosis of COVID-19(1,2), but nucleic acid detection has several
limitations, including the need for high specificity of primer sets, low
sensitivity, and the length of testing period. In comparison,
CT(Computed tomography) imaging offers a simple, fast, and highly
sensitive means to elucidate the extent and nature of lung tissue in
COVID-19. After analyzing the CT images of confirmed COVID-19, we
noticed that the signs of secondary pulmonary lobular structures were
commonly associated with all stages of COVID-19. Recognizing the
underlying secondary pulmonary lobular structural image signs can enable
us to understand the typical or atypical CT characteristics of COVID-19,
so as to provide reliable imaging diagnosis and differential diagnosis
for clinical early diagnosis and prognosis judgment(3).