A case-control evaluation of pulmonary and extrapulmonary findings of incidental asymptomatic COVID-19 infection on FDG PET-CT

Objectives: To describe the findings of incidental asymptomatic COVID-19 infection on FDG PET-CT using a case-control design. Methods: Incidental pulmonary findings suspicious of asymptomatic COVID-19 infection on FDG PET-CT were classified as a confirmed (positive RT-PCR test) or suspected case (no/negative RT-PCR test). Control cases were identified using a 4:1 control:case ratio. Pulmonary findings were re-categorised by two reporters using the BSTI classification. SUV metrics in ground glass opacification (GGO)/consolidation (where present), background lung, intrathoracic nodes, liver, spleen, and bone marrow were measured. Results: 7/9 confirmed and 11/15 suspected cases (COVID-19 group) were re-categorised as BSTI 1 (classic/probable COVID-19) or BSTI 2 (indeterminate COVID-19); 0/96 control cases were categorised as BSTI 1. Agreement between two reporters using the BSTI classification was almost perfect (weighted κ = 0.94). SUVmax GGO/consolidation (5.1 vs 2.2; p < 0.0001) and target-to-background ratio, normalised to liver SUVmean(2.4 vs 1.0; p < 0.0001) were higher in the BSTI 1 & two group vs BSTI 3 (non-COVID-19) cases. SUVmax GGO/consolidation discriminated between the BSTI 1 & two group and BSTI 3 (non-COVID-19) cases with high accuracy (AUC = 0.93). SUV metrics were higher (p < 0.05) in the COVID-19 group vs control cases in the lungs, intrathoracic nodes, and spleen. Conclusion: Asymptomatic COVID-19 infection on FDG PET-CT is characterised by bilateral areas of FDG avid (intensity > x2 liver SUVmean) GGO/consolidation and can be identified with high interobserver agreement using the BSTI classification. There is generalised background inflammation within the lungs, intrathoracic nodes, and spleen. Advances in knowledge: Incidental asymptomatic COVID-19 infection on FDG PET-CT, characterised by bilateral areas of ground glass opacification and consolidation, can be identified with high reproducibility using the BSTI classification. The intensity of associated FDG uptake (>x2 liver SUVmean) provides high discriminative ability in differentiating such cases from pulmonary findings in a non-COVID-19 pattern. Asymptomatic COVID-19 infection causes a generalised background inflammation within the mid-lower zones of the lungs, hilar and central mediastinal nodal stations, and spleen on FDG PET-CT. A case-control evaluation of pulmonary and extrapulmonary findings of incidental asymptomatic COVID-19 infection on FDG PET-CT.

The Spectrum of Chest CT-Scans in the Hospitalized Patients with the Coronavirus Disease

Background: Coronaviruses are a large family of RNA viruses, which range from the common cold virus to the causative agent of more severe diseases. Coronavirus was declared a pandemic in December 2019 in Wuhan, China. Iran has been an endemic zone for the spread of the coronavirus since the outset of this global epidemic and has remained among the countries largely affected by high rates of the disease. Objectives: The present study aimed to investigate the range of the chest computed tomography (CT) scan findings among the hospitalized patients with COVID-19 in Kermanshah, Iran during March-April 2020 to contribute to the accurate diagnosis of the infected patients. Methods: The sample population consisted of 286 hospitalized patients diagnosed with or suspected of the coronavirus disease. Chest CT-scan images and clinical data were reviewed, and their correlation was analyzed. Results: In total, 176 patients (61.53%) were male, and 110 (38.47%) were female. The mean age of the patients was 56 years. Polymerase chain reaction (PCR) results showed that 35.31% of the cases had coronavirus, while the results were negative in 64.69% of the cases. In addition, the CT-scan findings indicated 77.27% abnormal and 22.73% normal chest CT-scans. Among the patients, 75.87% recovered completely, and 18.53% died. The major CT abnormalities were diffuse ground-glass opacification (35.66%), peripheral ground-glass opacification (bilateral; 21.33%), and a combination of diffuse and peripheral ground-glass lesions (18.88%). The consolidation lesion of one lobe was detected in 16 patients, and the consolidation lesion of more than one lobe was observed in 40 patients. Conclusions: According to the results, the most common chest CT-scan findings in COVID-19 include diffuse ground-glass opacification, peripheral ground-glass opacification (bilateral), central ground-glass opacification (bilateral), a combination of diffuse and peripheral ground-glass opacification, a combination of central and peripheral ground-glass opacification, the consolidation lesion of one lobe, and the consolidation lesion of more than one lobe. Furthermore, significant correlations were observed between the CT-scans and the main clinical symptoms, while no significant correlations were denoted between the chest CT-scan and PCR results.