Predictive Value of 68Ga-FAPI-04 PET/MR for Left Ventricular Remodeling in Patients with Acute Myocardial Infarction

Purpose To observe longitudinal changes of myocardial fibroblasts activation by 68Ga-labeled fibroblast activation protein inhibitor (68Ga-FAPI-04) PET/MR in patients with ST-segment elevated myocardial infarction (STEMI), and assess its predictive value for late left ventricular remodeling (LVR). Methods Forty-two patients with STEMI were included in the study. 68Ga-FAPI-04 PET/MR was performed at baseline (5.1 ± 3.0 days) and at 12 months (12.0 ± 1.1 months) after STEMI. The extent of activated myocardial fibroblasts were quantified using 68Ga-FAPI-04 uptake volume (UV). Infarct size was expressed as late gadolinium enhancement (LGE) volume. LVR was defined as > 10% increase in left ventricular end-systolic volume (LVESV) from baseline to 12 months measured by echocardiography. Results Baseline 68Ga-FAPI-04 uptake volume (UV) was a significant predictor of the change in LVESV (B = 0.083, p = 0.023) from baseline to 12 months after AMI. The LVR group demonstrated higher 68Ga-FAPI-04 UV at baseline than the non-LVR group (p = 0.013). The area under the curve (AUC) of 68Ga-FAPI-04 UV at baseline for predicting the LVR reached 0.833 (p = 0.019), with sensitivity of 100.0% and specificity of 60.0%. Conclusion 68Ga-FAPI-04 PET/MR is a useful tool to non-invasively quantify myocardial fibroblasts activation, and baseline 68Ga-FAPI-04 UV in the early stage of STEMI may have predictive value for the late LVR.