Recent implications of FAPI PET in cardiac diseases

Fibroblast activation protein (FAP), highly expressed in activated fibroblasts within injured myocardium, serves as the molecular target for FAP inhibitor (FAPI)‐based imaging. Among developed radiopharmaceuticals, 68 Ga‐FAPI and 18 F‐FAPI demonstrate rapid target‐tissue accumulation and low background signals, yielding superior imaging characteristics. While FAPI positron emission tomography (PET) is widely used in oncology, its cardiac applications are emerging. This review examines the role of FAPI imaging across major cardiac conditions—including myocardial infarction, hypertrophic cardiomyopathy, dilated cardiomyopathy, and cardiac amyloidosis—and critically evaluates its diagnostic performance against established modalities (e.g., fluorodeoxyglucose (FDG) PET, cardiac magnetic resonance imaging [MRI]). We further discuss technical considerations, limitations, and future directions for optimizing FAPI‐based cardiovascular molecular imaging, highlighting its potential to advance early diagnosis, risk stratification, and therapeutic monitoring in cardiac diseases.