Reproducibility of compartmental modelling of 18F-FDG PET/CT to evaluate lung inflammation

PET Imaging of Translocator Protein as a Marker of Malaria-Associated Lung Inflammation

Purpose. Malaria-associated acute respiratory distress syndrome (MA-ARDS) is a severe complication of malaria despite effective anti-malarial treatment. Currently, non-invasive imaging procedures such as chest X-rays are used to assess oedema in established MA-ARDS but earlier detection methods are needed to reduce morbidity and mortality. The early stages of MA-ARDS are characterized by the infiltration of leukocytes, in particular monocyte/macrophages, thus monitoring of immune infiltrates may provide a useful indicator of early pathology. Procedures. Plasmodium berghei ANKA-infected C57BL/6 mice, a rodent malaria model of MA-ARDS, were longitudinally imaged using the TSPO imaging agent [¹⁸F]FEPPA as a marker of macrophage accumulation during the development of pathology and response to combined artesunate and chloroquine diphosphate therapy (ART+CQ). [¹⁸F]FEPPA uptake was compared to blood parasitemia levels and pulmonary immune cell infiltrates using flow cytometry. Results. Infected animals showed rapid increases lung retention of [¹⁸F]FEPPA, correlating well with increases in blood parasitemia and pulmonary accumulation of interstitial inflammatory macrophages and MHC II+ alveolar macrophages. Treatment with ART+CQ therapy abrogated this increase in parasitemia and significantly reduced both lung uptake of [¹⁸F]FEPPA and macrophage infiltrates. Conclusions. Retention of [¹⁸F]FEPPA in the lungs is well correlated with changes in blood parasitemia and lung associated macrophages during disease progression and in response to ART+CQ therapy. With further development TSPO biomarkers may have the potential to be able to accurately assess early onset of MA-ARDS.

Consensus Recommendations on the Use of 18F-FDG PET/CT in Lung Disease

PET with 18F-FDG has been increasingly applied, predominantly in the research setting, to study drug effects and pulmonary biology and to monitor disease progression and treatment outcomes in lung diseases that interfere with gas exchange through alterations of the pulmonary parenchyma, airways, or vasculature. To date, however, there are no widely accepted standard acquisition protocols or imaging data analysis methods for pulmonary 18F-FDG PET/CT in these diseases, resulting in disparate approaches. Hence, comparison of data across the literature is challenging. To help harmonize the acquisition and analysis and promote reproducibility, we collated details of acquisition protocols and analysis methods from 7 PET centers. From this information and our discussions, we reached the consensus recommendations given here on patient preparation, choice of dynamic versus static imaging, image reconstruction, and image analysis reporting.

Potential Applications of PET Scans, CT Scans, and MR Imaging in Inflammatory Diseases: Part II: Cardiopulmonary and Vascular Inflammation

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans.