Infective endocarditis (IE) is an infectious disease that affects the endothelium of the large intrathoracic vessels, heart valves, and intra-cardiac foreign body material. A 20-year-old woman was admitted to the cardiology department with complaints of fever and palpitations. Transthoracic echocardiography revealed a bicuspid aortic valve, aortic root enlargement, and aortic coarctation. Transesophageal echocardiography revealed a bicuspid aortic valve, but there was no vegetation. Methicillin-sensitive Staphylococcus aureus was identified on a blood culture. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) revealed increased intensive glucose uptake on the dilated aortic segment adjacent to the distal coarctation zone. Several reports have shown promising results for radio-labelled white blood cell single-photon emission computed tomography and 18F-FDG PET-CT imaging in IE. To our knowledge, this is the first described case in which PET-CT revealed endarteritis of the descending aorta in a patient without prosthetic material.