FAP and fibrosis: Inspired by these findings, we investigated the changes of FAP which has been developed as an imaging maker of fibrosis, and found that the uptake of [18 F]-FAPI-42 was gradually increased via PET/CT imaging with the duration of pressure overload; in addition, the uptake of [18 F]-FAPI-42 is RV is associated with cardiac fibrosis detected by tissue staining.