FDG-PET/CT of COVID-19 and Other Lung Infections

Abstract

While not conventionally used as the first-line modality, [ 18 F]-2-fluoro-2-deoxy-D-glucose (FDG) - positron emission tomography/computed tomography (PET/CT) can identify infection and inflammation both earlier and with higher sensitivity than anatomic imaging modalities [including chest X-ray (CXR), computed tomography (CT), and magnetic resonance imaging (MRI)]. The extent of inflammation and, conversely, recovery within the lungs, can be roughly quantified on FDG-PET/CT using maximum standardized uptake value (SUVmax) values. The Coronavirus disease 2019 (COVID-19) pandemic has highlighted the value of FDG-PET/CT in diagnosis, elucidation of acute pulmonary and extra-pulmonary manifestations, and long-term follow up. Similarly, many other pulmonary infections such as previously documented coronaviruses, Aspergillosis, Blastomycosis, Candidiasis, Coccidioidomycosis, Cryptococcosis, Histoplasmosis, Mucormycosis, and typical/atypical Mycobacterial infections have all been identified and characterized using FDG-PET/CT imaging. The goal of this review is to summarize the actual and potential benefits of FDG-PET/CT in the imaging of COVID-19 and other lung infections. Further research is necessary to determine the best indications and clinical applications of FDG-PET/CT, improve its specificity, and ultimately ascertain how this modality can best be utilized in the diagnostic work up of infectious pathologies.

Incidentally Detected PET-CT Imaging Findings Of COVID-19 Pneumonia: A Retrospective Study During Local Pandemic Era

“…Making use of PET/CT in detection of asymptomatic COVID-19 infections in these patients provides an added benefit beyond its oncological aim. 27 Few studies also showed the importance of the application of hygienic measures, contact minimisation, and usage of personal protective equipment for the safety and protection of the health personnel as well as patients. 28 Another important aspect to be noted is that, once the findings are detected, appropriate action and treatment can be undertaken with clinical monitoring.…”

The Clinical Utility of Molecular Imaging in COVID-19: An Update

“…Findings on PET/CT in these early reports described heterogeneous or diffuse FDG uptake in ground glass opacities and consolidation, predominantly with a subpleural distribution ( Figure 1 ). 10 , 11

Figure 1 62-year-old male patient with history of lymphoma underwent PET/CT scan for restaging. PET maximum intensity projection (MIP) images (A,D) and axial PET/CT fusion images (B) shows hypermetabolic bilateral predominantly subpleural areas (arrows) with the highest SUV max of 8.7, corresponding to ground glass opacities and solid consolidations on the axial low dose CT scan.

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COVID-19-Associated Pulmonary Mucormycosis

“…but also assess the extent of disease and follow up to assess residual infection status [27]. Recently, 18F-FDG-labeled leukocyte scan has been used to aid in the diagnosis of disseminated mucormycosis (pulmonary and intestinal) in a post-COVID-19 patient with other co-morbidities, including diabetes mellitus and post renal transplant status.…”

“…FDG PET/CT can be a particularly useful modality in patients with multiple risk factors for invasive fungal disease (IFD), to not only diagnose pulmonary fungal infections but also assess the extent of disease and follow up to assess residual infection status [ 27 ]. Recently, 18F- FDG–labeled leukocyte scan has been used to aid in the diagnosis of disseminated mucormycosis (pulmonary and intestinal) in a post-COVID-19 patient with other co-morbidities, including diabetes mellitus and post renal transplant status.…”