Myocardial Activity at ¹⁸F-FAPI PET/CT and Risk for Sudden Cardiac Death in Hypertrophic Cardiomyopathy

Fibroblast Activation Protein Inhibitor (FAPI)-Based Theranostics—Where We Are at and Where We Are Heading: A Systematic Review

“…Since fibroblast activation can remodel the tissue in fibrosis, inflammation and tissue healing, this may lead to tracer uptake in non-cancerous tissue. It is also worth noting that FAPI tracers have also been studied in non-oncologic diseases, such as IgG4-related disease [ 50 ], cardiac amyloidosis [ 51 , 52 , 53 ], risk of sudden cardiac death [ 54 ], tuberculosis [ 55 ], Crohn’s disease [ 56 ], Erdheim–Chester disease [ 57 ], arthritis and fibrosis. A slight uptake is also seen in the thyroid that may increase in cases of chronic thyroiditis and immune related thyroiditis [ 58 , 59 ].…”

A spotlight on fibroblast-activated protein inhibitor (FAPi) cardiovascular imaging

“…This prognostic role of FAPI-imaging seems to be confirmed also in another clinical scenario, which has a different etiology but shares a similar fibroblasts-mediated pathophysiological mechanism leading to myocardial fibrosis. In a recent study on patients with hypertrophic cardiomyopathy, FAPI-uptake was associated with 5-year risk of sudden cardiac death [22].…”

Displays of 18F-FAPI PET/CT in Myocarditis With Variable Symptom Durations

“…5,6 PET/CT imaging with FAP inhibitor (FAPI) radiotracers that targets FAP can visualize activated fibroblasts in myocardium and diagnose the possibility of myocardial fibrosis. [7][8][9] However, 18 F-FAPI uptake in myocardium is limited by the number of activated fibroblasts and maturation of fibrocytes. Three patients with clinically suspected myocarditis who participated in the 18 F-FAPI PET/CT clinical trial (NCT05824962) had different durations of symptoms and exhibited varying degrees of 18 F-FAPI uptake, in which the patient with a symptom duration of 1 week having the strongest uptake.…”

“…In myocarditis, FAP expression upregulates for myocardial repair and remodeling 5,6 . PET/CT imaging with FAP inhibitor (FAPI) radiotracers that targets FAP can visualize activated fibroblasts in myocardium and diagnose the possibility of myocardial fibrosis 7–9 . However, 18 F-FAPI uptake in myocardium is limited by the number of activated fibroblasts and maturation of fibrocytes.…”