Current and Emerging Knowledge in COVID-19

Abstract

COVID-19 has emerged as a pandemic leading to a global public health crisis of unprecedented morbidity. A comprehensive insight into the imaging of COVID-19 has enabled early diagnosis, stratification of disease severity, and identification of potential sequelae. The evolution of COVID-19 can be divided into early infectious, pulmonary, and hyperinflammatory phases. Clinical features, imaging features, and management are different among the three phases. In the early stage, peripheral ground-glass opacities are predominant CT findings, and therapy directly targeting SARS-CoV-2 is effective. In the later stage, organizing pneumonia or diffuse alveolar damage pattern are predominant CT findings and anti-inflammatory therapies are more beneficial. The risk of severe disease or hospitalization is lower in breakthrough or Omicron variant infection compared with nonimmunized or Delta variant infections. The protection rates of the fourth dose of mRNA vaccination were 34% and 67% against overall infection and hospitalizations for severe illness, respectively. After acute COVID-19 pneumonia, most residual CT abnormalities gradually decreased in extent, but they may remain as linear or multifocal reticular or cystic lesions. Advanced insights into the pathophysiologic and imaging features of COVID-19 along with vaccine benefits have improved patient care, but emerging knowledge of post–COVID-19 condition, or long COVID, also presents radiology with new challenges. © RSNA, 2023 Supplemental material is available for this article.

Clinical and Immunological Characteristics of Prolonged SARS-CoV-2 Omicron Infection in Hematologic Disease

“…Regardless of the PCR status, patients with HD should be carefully monitored to ensure timely treatment initiation before irreversible lung injury occurs. 33 This study has several limitations that should be addressed in future studies. First, the retrospective design and small sample size precluded multivariate analysis from weighing the relative contributions of B-and T-cell depletion to viral persistence.…”

Radiologic Findings after COVID-19 and the Correlation with Lung Function

“…The term “long COVID” became widely known in society and dedicated studies were proposed. These studies are demonstrating the long-term findings in COVID-19 [ 5 ], as well as the changing pattern of disease with the effects of vaccine programs and new variants [ 6 , 7 ]. Clearly, the imaging findings are evolving and must be evaluated in the context of clinical symptoms.…”

“…Fourth, although these imaging findings are highly relevant in the long-term assessment of symptomatic patients after COVID-19 infection, other modalities are also starting to offer insight into the pathophysiologic characteristics of this illness. For instance, the application of dual energy CT [ 6 , 7 ] will allow the study of perfusion abnormalities, while xenon 129 MRI has been effective in demonstrating oxygen transfer limitations with reduced red blood cell oxygenation and reduced diffusion capacity in the lung tissue [ 8 , 9 ].…”

“…Finally, with the changing Together with the fact that relatively few patients following the initial COVID-19 wave have persistent symptoms and imaging findings, this should fill us with hope to be able to live with COVID-19 in the future virus and vaccination programs, it appears that this disease is less severe in symptoms as well as imaging findings [ 6 , 7 ]. Together with the fact that relatively few patients following the initial COVID-19 wave have persistent symptoms and imaging findings, this should fill us with hope to be able to live with COVID-19 in the future.…”

Ventilation Defects at 129Xe MRI in Postacute COVID-19 Syndrome: Back to Normal after 1 Year?

“…PACS is characterized by persistent symptoms and/or delayed or long-term complications beyond 4 weeks from the onset of symptoms. These symptoms are frequently seen and are not limited to those patients who have experienced the most severe forms of COVID-19 ( 1 - 3 ).…”