Imaging Progression Under Low Respiratory Viral Load of SARS-CoV-2 Omicron Variant Infection: A Retrospective Study in China

Abstract

Purpose

To investigate the computed tomography (CT) findings of SARs-CoV-2 Omicron variant in relation to respiratory viral loads determined by cycle threshold values in reverse-transcription polymerase chain reaction (RT-PCR).

Materials and Methods

From October 2022 to November 2022, 74 hospitalized patients with Omicron were included in this retrospective study. The radiological features, CT involvement scores in relation to the respiratory viral load, and factors associated with imaging progression (IP) after the RT-PCR results turned negative were analyzed.

Results

The most common CT patterns of Omicron were multiple round-like or patchy ground-glass opacity (GGO) or mixed GGO in the peripheral or diffuse areas. The grading of CT involvement scores exhibited an inverse pattern compared to viral loads from day 1 to day 8 and from day 13 to day 20 after diagnosis. Among the 65 patients with complete imaging data, 45 (69.23%) showed IP with clinical warning indicators of disease exacerbation negative in 34 and positive in 11. Patients with IP were older than those with non-IP (NIP); the erythrocyte sedimentation rates, procalcitonin levels, and D-dimer levels on admission of patients with IP were significantly higher than those of patients with NIP, whereas the immunoglobulin (Ig) G antibody level on admission and CT involvement score on initial CT of patients with IP were significantly lower than those of patients with NIP (all P < 0.05).

Conclusion

For patients with Omicron, the IP of lung abnormalities is common when the viral load decreases. Under these circumstances, paying attention to clinical warming indicators of disease progression may contribute to better patient management and the mitigation of severe pneumonia.

Keywords:

• severe acute respiratory syndrome coronavirus-2
• Omicron
• pneumonia
• computed tomography
• viral load

Abbreviations

Ct, cycle threshold; E, envelope; GGO, ground-glass opacity; Ig, immunoglobulin; IP, imaging progression; N, nucleocapsid; ORF1ab, open reading frame 1ab; RdRp, RNA-dependent RNA polymerase; RT-PCR, reverse-transcription polymerase chain reaction; S, pike; SARS-CoV-2, severe acute respiratory syndrome coronavirus-2.

Data Sharing Statement

Data supporting the results reported in the manuscript can be found by contacting the correspondence author with email ([email protected]).

Ethics Approval and Informed Consent

Chongqing University Three Gorges Hospital’s institutional review board approved this study, and informed consent was obtained from all individual participants included in the study. This retrospective study complies with the Declaration of Helsinki and abides by the principle of confidentiality, ensuring non-disclosure of patient information.

Consent for Publication

The details of any images, recordings, and figures can be published, and the persons providing consent have been shown the article contents to be published.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This study was supported by Chongqing medical scientific research project (Joint project of Chongqing Health Commission and Science and Technology Bureau) (2022MSXM147) and Chongqing Health Commission (Chongqing Talent Program-Innovation leading Talent Research Project) (CQYC20210303348) of China.