Investigating Inflammation and Tissue Remodeling in ILD with [ ¹¹ C]NES and [ ⁶⁸ Ga]Ga-FAPI-46 PET Imaging

Interstitial lung diseases (ILDs) encompass a large number of conditions that affect the lungs, characterized by varying degrees of inflammation and fibrosis. Accurate diagnosis and monitoring of ILDs remain challenging due to the complex nature of ILDs and the limitations of conventional diagnostic methods such as high-resolution computed tomography and pulmonary function tests. Methods Fourteen patients with different ILDs and four healthy controls underwent positron emission tomography (PET) imaging using [ 11 C]NES followed by [ 68 Ga]Ga-FAPI-46, to visualize and quantify neutrophil elastase and fibroblast activated protein in the lungs, respectively. On the same day of the PET examination, blood samples were collected from the participant to measure various immune biomarkers in order to compare between PET results, serum biomarker levels, and clinical observations. Results Uptake of both radiotracers were higher in the lungs of ILD patients compared to healthy controls, with particularly strong uptake in regions showing CT features of fibrosis. [ 68 Ga]Ga-FAPI-46 generally exhibited higher uptake than [ 11 C]NES in these fibrotic areas. Despite the elevation of several immune biomarkers compared to healthy controls, no clear correlation was found between these biomarkers and PET imaging results. Conclusion These preliminary results support the potential of [ 11 C]NES and [ 68 Ga]Ga-FAPI-46 PET/CT imaging as promising non-invasive methods for assessing neutrophil-mediated inflammation and tissue remodeling activity in the lungs of ILD patients.