- Imaging in Intensive Care Medicine
- Published: 19 June 2024
18F-fluorodeoxyglucose positron emission tomography/computed tomography differentiates between pneumonia and atelectasis in a mechanically ventilated patient
Intensive Care Med (2024). https://doi.org/10.1007/s00134-024-07505-5
Differentiation between atelectasis and pneumonia in critically-ill patients can be challenging on regular computed tomography (CT). In this image the additional value of a 18F-fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) scan to discriminate is demonstrated. This scan was requested to study dissemination of an infection in a 61-year-old male, who was admitted to the intensive care due to multiple organ failure. Figure 1 shows normal physiological uptake in the myocardium (pink arrow), bilateral pleural effusion (white arrow), atelectasis with slightly elevated [18F]FDG uptake in the left lower lobe (orange arrow) and atelectasis with high [18F]FDG uptake in the right lower lobe (green arrow). The high [18F]FDG uptake is likely due to an infectious focus. This was confirmed by a subsequent positive sputum culture positive for Serratia marcescens, which confirmed the diagnosis of a ventilator associated pneumonia.
The low-level [18F]FDG uptake noticed in atelectasis is associated with low grade inflammation and not with increased tissue density of the lung. The intensive [18F]FDG uptake in the right lower lobe of the lung indicates a much larger local inflammatory response most likely caused by an infection. Ultimately, this image emphasizes the potential of [18F]FDG PET/CT to differentiate between infectious and inflammatory pulmonary abnormalities in critically ill patients.
A Maximum Intensity Projection. B Transversal [18F]FDG PET image. C Transversal fusion image of [18F]FDG PET/CT. α = 0.5. Standardized Uptake Value scale from 0 to 5. Arrows: green: infection, orange: atelectasis, white: pleural effusion, pink: physiological myocardial uptake