dcyphr | Chest CT findings of COVID-19 pneumonia by duration of symptoms


The purpose of the study detailed here is to examine lung abnormalities in COVID-19 patients with CT scans and to see how these abnormalities are connected to how long they’ve had the disease. Scans performed on 112 patients show that CT scans could be used to measure the severity of lung damage in COVID-19 patients. These scans showed that the disease changes rapidly at first, but remains stable afterwards.


COVID-19 first appeared in Wuhan, China in December 2019 and pneumonia is a known complication of the disease. Those infected often experience fevers, dry coughs, and fatigue, and occasionally more serious symptoms. An assay using reverse transcription-polymerase chain reaction (RT-PCR) has been widely used to test people for COVID-19. However, this test is not always successful in detecting COVID-19 infection. This is usually due to either the test being incorrectly used, or the test’s low sensitivity. Recent experiences have shown that CT scans of the lungs may pick up on signs of COVID-19 infection faster than RT-PCR based tests. The study outlined in this article is intended to examine lung problems picked up by CT scans of COVID-19 patients. The study will also see how these problems are linked to how long a person has COVID-19 symptoms.

Materials and Methods

This study took place in February and March 2020 with 112 patients who had pneumonia originating from a COVID-19 infection. All of these patients were given lung CT scans to assess the severity of the disease and to monitor its progression over time.

CT scans were performed by two radiologists who then made lung assessments based on patterns seen in the imaging. The scans were categorized based on the amount of time that passed between the first appearance of symptoms and the scan itself. These categories ranged from stage 1, representing the shortest amounts of time, and stage 6, representing the longest amounts of time. The severity of the disease was also evaluated, along with the extent to which each major part of the lung was involved. Statistical analyses were conducted on the results of these scans.


It was found that the most common symptoms at the start of COVID-19 pneumonia were fever, dry coughing, fatigue, chest distress, and dyspnea (shortness of breath). Lab tests that measured components in the blood were also conducted on the patients. There were some deviations from the normal levels of these components, such as lower lymphocyte numbers and slightly more C-reactive protein.

Lesions, which are abnormal / damaged regions of the lung, often come with COVID-19 pneumonia. From the CT scans, it was shown that lesions were mostly found away from the center of the lungs. As the disease progressed, these lesions often moved inward towards the center of the lungs. Lesions were often present in multiple lobes of the lungs.

The lower lobes of the lung were more likely to be involved with the disease.


In this study, the authors analyzed the lung CT scans and the results of other lab tests on COVID-19 patients. Measurements were made across different stages of the disease.

Results of the CT scans seem to suggest that the disease first invades either the terminal respiratory bronchi or the alveoli. The intensity and nature of lung problems that come with COVID-19 seem to vary depending on how long one has had the disease. Additionally, the authors found that the disease changes rapidly during the first 10 days after infection, but remains relatively the same afterwards.

This study has a few limitations, such as the fact that only 112 patients were examined and no follow-up observations of lung changes at thin-section CT scans were done. 

Overall, this study shows the potential for CT scans to be used to assess the changes and severity of lung abnormalities in COVID-19 patients.