Imaging of cardiac fibroblast activation in a patient after acute myocardial infarction using Ga-FAPI-04.

Our previous study has demonstrated the feasibility of noninvasive imaging of fibroblast activation protein (FAP)-expression after myocardial infarction (MI) in MI-territory in a rat model with Ga-FAPI-04-PET. In the current extended clinical case, we sought to delineate cardiac uptake of Ga-FAPI-04 in a patient after MI with clinical indication for the evidence of fibroblast activation. Carcinoma patients without cardiac disease underwent Ga-FAPI-04-PET/CT as control. The patient with one-vessel disease underwent dynamic Ga-FAPI-04-cardiac-PET/CMR for 60 minutes. Correlation of cardiac Ga-FAPI-04 uptake with clinical findings, ECG, echocardiography, coronary-arteriography and enhanced cardiac-MRI with T1 MOLLI and ECV mapping were performed. No uptake was found in normal myocardium and in mature scar. A focal intense Ga-FAPI-04 uptake with continuous wash-out in the infarct territory of coronary occlusion correlating with T1 and ECV mapping was observed. The uptake of Ga-FAPI-04 extends beyond the actual infarcted area and overestimates the infarct size as confirmed by follow-up CMR.