Application Value of 68Ga-FAPI PET/CT in the Evaluation of Myelofibrotic Diseases

Abstract

Purpose Fibroblast activation protein is highly expressed in neoplastic lesions and various fibrotic tissues, making it an attractive target for disease evaluation. 68Ga-labeled fibroblast activation protein inhibitor (FAPI), a new tumor interstitial imaging agent, holds promise for evaluating myelofibrosis. Therefore, this study aimed to use 68Ga-FAPI PET/CT for the noninvasive visualization and quantification of the extent of myelofibrosis. Patients and Methods This was a prospective clinical study involving 22 patients with myelofibrosis who underwent 68Ga-FAPI PET/CT. The uptake of 68Ga-FAPI was measured in their respective bone marrow and spleen, and the obtained imaging findings were compared with laboratory, cytogenetic, and histopathological data. Results 68Ga-FAPI uptake in the bone marrow was significantly and positively correlated with the myelofibrosis grade (r > 0.8, P < 0.001). 68Ga-FAPI PET/CT showed visually negative results in patients with grades 0–1 myelofibrosis and positive in those with grades 2–3, but the level of involvement varied. 68Ga-FAPI PET/CT provides a noninvasive means of visualizing the extent of systemic bone marrow involvement and differentiation between the early and advanced stages of fibrosis. Conclusions 68Ga-FAPI PET/CT shows promise as a method for visualizing and quantifying myelofibrosis, providing suitable sites for bone marrow biopsy. The extent of 68Ga-FAPI uptake by bone marrow increases with the progression of myelofibrosis, thus it is a simple and noninvasive measurement that can be used to evaluate the progression of myelofibrosis. Nevertheless, although 68Ga-FAPI PET/CT has demonstrated a potential value in prognostic assessment, further confirmation is needed.