A 62-year-old man was admitted to our hospital due to recurrent abdominal pain for 3 months and worsened for 1 week. He has a history of hypertension for 20 years. Echocardiogram showed thickened septum and decreased left ventricular diastolic function, indicating hypertensive heart disease. Endoscopy-pathology and fluorescence in situ hybridization was performed due to suspected gastric cancer but these examinations came up with contradict results. He subsequently underwent an 18F-AIFNOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) scan to determine the likelihood of malignancy.
The PET/CT image showed no aberrant tracer uptake in the stomach, but unexpected uptake was observed in inferolateral wall of his left ventricular myocardium (Fig. 1, arrow in A, maximum intensity projection image). The uptake was also noted in CT, PET, and fusion images from different views (Fig. 1: C–E, axial CT, PET, and fusion images; F–H, coronal CT, PET, and fusion images; I-K, sagittal CT, PET, and fusion images). Whereas no uptake was noted in other myocardial walls. Polar map (Fig. 1H) also demonstrated spatial 18F-AIFNOTA-FAPI-04 uptake in the inferolateral wall of left ventricular myocardium.
Fibroblast activation protein (FAP)-targeted PET/CT is a novel imaging technique that targets FAP expression, which is upregulated in the process of fibrosis 1. 68Ga-FAPI is the most commonly used PET agent but is limited by the relatively short half-life of 68Ga and the restricted availability of the 68Ge/68Ga generator. 18F-FAPI is a novel PET radiotracer which benefits from the longer half-life and more convenient availability of 18F 2. In this case, the 18F- FAPI-04 accumulation in the inferolateral wall suggests fibroblast activity and fibrosis in this part of myocardium, which is most likely caused by long-time hypertension. This case suggests the possible value of 18F-FAPI PET/CT in the evaluation of cardiac fibrosis/remodeling induced by hypertension.