Since the outbreak of the new coronavirus pneumonia (2019-nCov) epidemic, the number of deaths caused by new coronavirus pneumonia has been increasing as the number of daily diagnoses has continued to increase (13). Therefore, how to diagnose the disease accurately and quickly is crucial for appropriate treatment so as to save lives and control the epidemic.
The results of the present study demonstrated that the fact the diagnosis accuracy HRCT features combined with epidemiological history is similar to the detection of viral nucleic acid. The detection of viral nucleic acid is considered gold standard for the diagnosis of 2019-nCoV pneumonia (9). However, there are following disadvantages: first, the nucleic acid test is time-consuming, and if it is negative, repeated sampling may be necessary, which would prolong the diagnostic time and increase chance of the further spread of the virus; second, although the specificity of the nucleic acid test is high, there is a certain false negative rate. The above shortcomings are difficult to cope with the large number of close contacts and family watchers.
For chest HRCT examination, although it lacks the specificity for viral pneumonia and may appear “different diseases with same imaging features”, typical HRCT features combined with epidemiological history held high good sensitivity similar to the detection of viral nucleic acid. Authors acknowledge that the chest CT cannot replace nucleic acids to confirm the diagnosis of new coronavirus pneumonia. However, in the face of conditions where nucleic acid testing conditions are not allowed in the epidemic area, and a large number of suspected cases cannot be diagnosed, chest HRCT examination combined with epidemiological history can be used as a powerful supplementary method to carry out leak detection and make up for defects, so as to find more suspected cases and close contacts in early phase, so that they could be isolated, observed and treated as soon as possible.
According to the Guidelines for Imaging Diagnosis of novel Coronavirus (1st edition 2020) (11),our study cases were classified as early stage (n = 36), progressive stage (n = 32) and severe stage (n = 4). In early stage imaging findings, lesions were mostly distributed in the peripheral or sub-pleural lung and generally do not involve the whole lung segment. At the same time, the lesions were always multifocal in both lungs, rare single focus, which commonly manifest as ground glass opacity, with or without interlobular septal thickening, and rarely as small and limited consolidation range. When the disease was in the progressive stage, the distribution of lesions was increased and involved multiple lobes, mostly located in sub-pleural region of the lungs. Some of the lesions were enlarged with increased density, irregular, fan-shaped or wedge-shaped, with unclear boundaries, showing bilateral asymmetry. If treatment was delayed or treated inappropriately, diffuse lesions can be seen in both lungs, with a few”white lung “manifestations. The range of lesions increased by 50% within 48 hours, and the lesions were mainly consolidation, with ground glass opacity, air bronchogram, and multiple cable- like shadows.
Moreover, our study showed 10 [13.89%]) of the 2019-nCoV-infected patients were aged 19–39 years, 40 (55.56%) were aged 40–59 years and 22 (30.56%) were aged over 60 years. However, no children or adolescents were infected. Author acknowledge that this results might be misleading and may be due to the fact that the children have few opportunities to go out and have less chance of contacting the source of infection; therefore, the probability of infection is low.
The study have several limitations. First, the sample size in our study was relatively small and there were no cases of children. Second, we did not review follow-up CT imaging. Third, we did not count false positive cases of CT imaging, as these cases were not included in this study.
In conclusion, the HRCT features of 2019-nCoV pneumonia are characteristic to assess scope and type of lesions, which when combined with epidemiological history yield high clinical value for the diagnosis of 2019-nCoV pneumonia.