Abstract
Purpose
The goals were to explore the correlation of 18F-labeled fibroblast activation protein inhibitor (FAPI) and cardiovascular magnetic resonance (CMR) parameters in ST-elevation myocardial infarction (STEMI) patients with successful primary percutaneous coronary intervention (PPCI) and to investigate the value of FAPI imaging in predicting cardiac functional recovery.
Methods
Fourteen first-time STEMI patients (11 men, mean age: 62 ± 11 years) after PPCI were prospectively recruited. All patients underwent baseline FAPI imaging (6 ± 2 days post-MI) and CMR (8 ± 2 days post-MI). Ten patients had convalescent CMR (84 ± 4 days post-MI). Myocardial FAPI activity was analyzed on extent (the percentage of FAPI uptake volume over the left ventricular volume, FAPI%), intensity (target-to-background uptake ratio, TBRmax), and amount (FAPI%×TBRmax). Serum biomarkers during the acute phase, late gadolinium enhancement (LGE), T2-weighted imaging (T2WI), extracellular volume (ECV), microvascular obstruction (MVO), and cardiac function from CMR imaging were analyzed.
Results
Localized but inhomogeneous FAPI uptake was observed, which was larger than the edematous and infarcted myocardium. The MVO area showed lower FAPI uptake compared with the surrounding myocardium. FAPI activity was associated with myocardial injury biomarkers, T2WI, LGE, and ECV at both per-patient and per-segment levels (all p < 0.05). Among the CMR parameters, T2WI had the greatest correlation coefficient with both FAPI% and FAPI%×TBRmax. Baseline TBRmax was correlated with convalescent left ventricular ejection fraction (LVEF)(r = −0.73, p = 0.02).
Conclusion
FAPI imaging detects more involved myocardium than CMR in reperfused STEMI, and was associated with myocardial damage and convalescent LVEF.
Molecular imaging of fibroblast activation protein after myocardial infarction using the novel radiotracer [68Ga]MHLL1
