Chest imagingCase Type
Adeel Ejaz Syed, FRCR1; Alexander Zeinati, FRCR1; Roofia Tanvir, MBBS2; Erica Mulholland3, Nicola Mulholland, FRCR1; Marko Berovic, FRCR1Patient
59 years, female; 63 years, male; 83 years, female
We describe the 18-F FDG PET-CT appearances of COVID-19 in three outpatients.
Case 1: 59-year-old female with background lymphoma, presenting with shortness of breath
Case 2: 63-year-old male investigated for collapse
Case 3: 83-year-old female admitted with weight loss and raised C-Reactive Protein (CRP)
All three patients underwent an 18-Fluorine fluorodeoxyglucose positron emission tomography-computed tomography (18-F FDG PET-CT) study, with unenhanced free-breathing CT for attenuation correction.
In case 1, the PET-CT was performed 1 week after the patient’s acute presentation and revealed diffuse peripheral consolidation of basal predominance, which was intensely FDG-avid (SUVMax 7.6), no nodal enlargement and a complete metabolic response to lymphoma.
In case 2, the PET-CT was performed 2 weeks after the acute admission. Avid lymph nodes above and below the diaphragm in keeping with subsequently biopsy-proven lymphoma. In addition, moderate tracer uptake demonstrated in subpleural areas of ground-glass opacification (SUV max 3.7)
In case 3, the PET-CT was performed 5 weeks after acute admission to investigate possible vasculitis in a patient with eosinophilia and a splenic infarct. The scan demonstrated a photopaenic splenic infarct and non-FDG avid bilateral pleural effusions with no characteristic COVID-19 chest appearances.
The coronavirus (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has a propensity for causing a potentially fatal pneumonia. The infection fatality rate is estimated between 0.7% and 6.4% with poorer outcomes identified for those with co-morbidities.
The use of imaging in diagnosis, particularly CT, has demonstrated increased sensitivity than RT-PCR testing. The most common CT appearances of COVID-19 pneumonia are bilateral and subpleural areas of ground-glass opacification, lower lobe consolidation and occasionally crazy-paving appearances. However, these appearances are non-specific and encountered in other viral pneumonias such as influenza, SARS and MERS.
The emerging evidence is that microvascular thrombi are strongly associated with COVID-19 infection and contribute to the high D-dimer levels commonly seen in the typical blood changes. Correlating the CT findings with blood abnormalities of lymphopaenia, a raised CRP and raised D-dimer is important in raising the possibility of COVID-19 infection.
In case 1, the patient was admitted one week after the PET CT with shortness of breath. During the admission, she had a lymphopaenia of 0.8, a CRP of 187 and a D-dimer of 2892. Given the typical imaging and blood findings, she was treated clinically for COVID pneumonia despite a negative swab.
In case 2, PET CT was performed 3 days after the patient was discharged and 13 days after the positive swab. During admission, CRP was 174 and D-dimer was 1328.
In case 3, the PET CT was performed 34 days after the positive swab. At the time of the swab, the CRP was 286 and a lymphopaenia of 0.16.
In both cases 1 and 2, the typical CT appearances of COVID-19 pneumonia are demonstrated with concomitant increased FDG-avidity. The addition of functional imaging allows us to interpret whether there is an active glycolytic process within ground glass lung infiltrates.
Patients with COVID-19 may be investigated for co-existent pathology as thromboembolic complications are being reported in multiple organs. In case 3, The PET was of value in excluding vasculitis or any residual COVID-19 related inflammation but it showed a splenic infarct, a possible late COVID-19 complication.
All 3 patients in our series have been discharged home.
During the pandemic and recovery phase, PET-CT imaging continues for non-COVID indications. It is important for the radiologist to recognise the variable whole body findings on metabolic imaging.
 Chua F, Armstrong-James D, Desai SR, Barnett J, et al. The role of CT in case ascertainment and management of COVID-19 pneumonia in the UK: insights from high-incidence regions. Lancet Respir Med. 2020. (PMID: 32220663)
 Verity R, Okell lc, Dorigatti I, Winskill P, et al. Estimates of the severity of coronavirus disease 2019: a model-based analysis. Lancet Infect Dis. 2020 Mar 30. (PMID: 32240634)
 Guan W, Liang W, Zhao Y, Liang H, et al. Comorbidity and its impact on 1590 patients with Covid-19 in China: A Nationwide Analysis. Eur Respir J. 2020 Mar 26 : 2000547. (PMID: 32217650)
 Kanne J, Little B, Chung J, et al (2020): Essentials for Radiologists on COVID-19: An Update—Radiology Scientific Expert Panel. Radiology 2020 Feb 27:200527. (PMID: 32105562)
 Ai T, Yang Z, Hou H, Zhan C, et al. Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases. Radiology. 2020 Feb 26: 2600642. (PMID: 32101510)
 Fan B.E., Chong V.C.L., Chan S.S.W., et al. Hematologic parameters in patients with COVID-19 infection. Am J Hematol. 2020 Mar 4. (PMID: 32129508)