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Background: Myocardial fibrosis is a key healing response after myocardial infarction driven by activated fibroblasts. Gallium-68-labeled fibroblast activation protein inhibitor ([Ga]-FAPI) is a novel positron-emitting radiotracer that binds activated fibroblasts.
Objectives: The aim of this study was to investigate the intensity, distribution, and time-course of fibroblast activation after acute myocardial infarction.
Methods: A total of 40 patients with acute myocardial infarction underwent hybrid [Ga]FAPI-46 positron emission tomography and cardiac magnetic resonance and were compared with matched control subjects (n = 19) and those with chronic (>2 years) myocardial infarction (n = 20). Intensity of [Ga]FAPI-46 uptake was quantified by maximum target-to-background ratio (TBR). Burdens of fibroblast activation and scar were assessed by percent myocardial involvement of [Ga]FAPI-46 uptake and late gadolinium enhancement, respectively.
Results: Myocardial [Ga]FAPI-46 uptake was observed in the acute infarct and peri-infarct regions that exceeded the extent of late gadolinium enhancement (burden 27.8% ± 12.4% vs 15.2% ± 10.6%; P < 0.001). One-third of patients also demonstrated right ventricular involvement. Myocardial [Ga]FAPI-46 uptake was most intense at 1 and 2 weeks before declining at 4 and 12 weeks (TBR 4.0 ± 1.1, 3.7 ± 1.0, 3.1 ± 0.8, and 2.7 ± 0.7; P < 0.001). In comparison with control subjects, increased [Ga]FAPI-46 uptake was observed in chronic (7 ± 6 years ago) infarcts at lower intensity than acute infarction (TBR 1.2 ± 0.1 vs 1.7 ± 0.5 vs 4.0 ± 1.1; P < 0.001). Baseline [Ga]FAPI-46 burden correlated with lower left ventricular ejection fraction (r = -0.606), higher indexed left ventricular end-diastolic volume (r = 0.572), and higher scar burden (r = 0.871) at 1 year (P < 0.001 for all). Increased remote myocardial [Ga]FAPI-46 uptake was associated with left ventricular dilatation and systolic dysfunction.
Conclusions: Myocardial fibroblast activation peaks within a week of acute myocardial infarction and extends beyond the infarct region. It declines slowly with time, persists for years, and is associated with subsequent left ventricular remodeling. (PROFILE-MI-The FAPI Fibrosis Study; NCT05356923).
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http://dx.doi.org/10.1016/j.jacc.2024.10.103 | DOI Listing |
Lancet Oncol
September 2025
Department of Nuclear Medicine, West German Cancer Center, German Cancer Consortium and National Center for Tumor Diseases site, University Hospital Essen, Essen, Germany.
Background: The fibroblast activation protein α (FAP)-directed radiotracer [Ga]Ga-FAPI-46 for PET-CT has shown promising diagnostic accuracy in cancer staging in retrospective studies. We aim to investigate the positive predictive value (PPV) of [Ga]Ga-FAPI-46 PET for detecting FAP-expressing tumours and the potential association between PET radiotracer uptake intensity and immunohistochemical FAP expression.
Methods: This single-centre, single-arm, interventional, phase 2 trial was conducted at the University Hospital Essen, Essen, Germany.
Front Immunol
July 2025
Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany.
Purpose: After cochlear implantation, molecular processes at the electrode-nerve interface significantly influence the variability in clinical outcomes. The present study investigates molecular processes in a guinea pig model of cochlear implant (CI) using positron emission tomography/computed tomography (PET/CT) and correlates the imaging findings with histological analyses.
Methods: Animals were examined with PET in the 3 weeks and 9-12 months post-implantation using the inflammation marker [F]FDG and, at the later time points, [Ga]FAPI-46 as a marker for fibrosis.
J Nucl Med
September 2025
German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany.
Solitary fibrous tumor (SFT) is a rare soft-tissue sarcoma with limited treatment options, especially in advanced or metastatic cases. Fibroblast activation protein α (FAPα) is overexpressed in certain sarcomas, including SFTs, making it a promising target for diagnostics and radiopharmaceutical therapy (RPT). We present the cases of 3 patients with metastatic SFTs who, after exhausting standard treatments, underwent molecular profiling and showed elevated FAPα expression.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
July 2025
Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
Purpose: To overcome difficulties with regard to anatomic discrimination of intrapelvic tumors and non-specific intrapelvic uptake (i.e. excreted activity in the urinary bladder) by early acquisition of FAPI-PET in prone position.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
June 2025
Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, TA29, PO box: 30001, Groningen, The Netherlands.
Purpose: Post-acute sequelae of COVID-19 (PASC) has emerged as a major healthcare problem. A comprehensive mechanism of disease remains to be elucidated. In this study we aimed to explore pulmonary and muscle fibroblast activation protein (FAP) activity in former critical COVID-19 patients with persistent dyspnea, using [Ga]FAPI-46 PET/CT.
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