CT appearances, patterns of progression, and follow-up of COVID-19: evaluation on thin-section CT

Abstract

Background To retrospectively analyze CT appearances and progression pattern of COVID-19 during hospitalization, and analyze imaging findings of follow-up on thin-section CT. Methods CT findings of 69 patients with COVID-19 were evaluated on initial CT, peak CT, and pre-discharge CT. CT pattern were divided into four types on CT progression. Lesion percentage of pulmonary lobe (lobe score) was graded. Correlation analysis was made between scores and intervals. 53 patients were followed up by CT. Results Among 69 patients, 33.3% exhibited improvement pattern, 65.2% peak pattern, 1.5% deterioration pattern, and 0% fluctuation pattern. The lobe scores were positively correlated with most of intervals. It was more common to observe consolidation, pleural thickening and pleural effusion on the peak CT, and irregular line and reticulation on pre-discharge CT. The peak-initial interval were shortened when the initial CT with consolidation and pleural thickening. The intervals were extended when the irregular lines appeared on peak CT and reticulation on pre-discharge CT. Among 53 follow-up patients, 37.7% showed normal chest CT, and 62.3% showed viral pneumonia remained that mainly included GGO (100.0%) and irregular lines (33.3%). Conclusions COVID-19 displayed different appearances on CT as progressing. The peak pattern was the most common progression pattern. The CT appearances showed closely related to the intervals. The COVID-19 pneumonia can be remained or completely absorbed on CT with follow-up.

Long-Term Follow-Up Study of COVID-19: Evaluation on Thin-Slice CT

“…Then, in the absorption stage, the GGOs and consolidation were gradually absorbed, and fibrotic changes appeared, such as irregular linear opacities and reticular patterns. 6 , 13–15 Fibroplasia is a form of tissue injury and repair that results from the proliferation of fibroblasts, vascular endothelial cells, and connective tissue and finally forms fibrous tissue. 2 Therefore, in the late stages of COVID-19, fibrosis gradually appeared and was gradually absorbed.…”

“… 2–5 Our previous study on a short-term follow-up CT had also demonstrated that the pneumonia had been completely absorbed in 37.7% of 69 COVID-19 patients, and residual pneumonia in 62.3%. 6 The remained CT manifestations included GGO (62.3%), irregular lines (20.8%), reticulation (9.4%), consolidation (3.8%), and pleural thickening adhesion (3.8%). 6 There was one year follow-up study from the onset of symptoms recently, which showed 75% of 209 patients were completely absorbed, and 25% had residual lesions, including reticular patterns (13.4%) and irregular linear opacities (12.0%).…”

“… 6 The remained CT manifestations included GGO (62.3%), irregular lines (20.8%), reticulation (9.4%), consolidation (3.8%), and pleural thickening adhesion (3.8%). 6 There was one year follow-up study from the onset of symptoms recently, which showed 75% of 209 patients were completely absorbed, and 25% had residual lesions, including reticular patterns (13.4%) and irregular linear opacities (12.0%). 7 Another one-year follow-up study after discharge recently showed that the proportion of residual lesions in the lung was higher, i.e.63.5% (132/208).…”

The Additional Value of Lower Respiratory Tract Sampling in the Diagnosis of COVID-19: A Real-Life Observational Study

“…It is important to note that the diagnostic performance of CT scans does not depend merely on the prevalence of the disease in the population studied but is also affected by the nonspecific findings of COVID-19 that overlap with those of other conditions, resulting in a substantial rate of false–positive examinations [ 27 ]. Although accumulating data may suggest that a few radiological signs may be considered more specific for COVID-19 pneumonia [ 32 , 33 ], CT appearance is, indeed, not only nonspecific but also time-dependent, displaying predictable spatio–temporal changes [ 34 , 35 ]. Two main reasons could be given for false–negative results: first, symptomatic patients may not show lung abnormalities in the early course of the disease; second, a considerable number of patients with symptomatic upper respiratory tract infections do not develop pneumonia [ 36 ].…”

The Role of Ionizing Radiation for Diagnosis and Treatment against COVID-19: Evidence and Considerations

“…Subsequently, at the peak stage (9-13 days), consolidations can be demonstrated. Finally, at the absorption stage (>14 days) a gradual resolution of the findings may be initiated with "fibrous stripes" appearing and the abnormalities frequentlybut not always-resolving at one month and beyond [44,46]. Furthermore, imaging findings on CT can also vary according to the course of the disease at the time of imaging.…”