Fluorodeoxyglucose accumulation in the left atrial appendage of a patient with paroxysmal atrial fibrillation.

A 69-year-old man with a history of paroxysmal atrial fibrillation (PAF) and subsequent cerebral infarction was referred to our hospital because of an abnormal accumulation of 18F-fluorodeoxyglucose (FDG) in the left atrial appendage (LAA) that was detected on positron emission tomography-computed tomography (PET-CT) imaging during a health screening. Transesophageal echocardiography (TEE) demonstrated thrombus formation in the LAA. Even after the thrombus disappeared by strictly guided oral anticoagulant therapy, intense abnormal FDG uptake in the LAA on PET-CT imaging persisted. In low-risk patients such as this, inflammation may have played some role in LAA thrombus formation.