Acute saddle pulmonary embolism on F-FDG PET/CT: diagnosis by functional imaging.

F-labelled fluoro-2-deoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) is used extensively in the setting of cancer staging and in assessing cancer treatment response. Oncology patients have a sevenfold risk of developing pulmonary embolism (PE) due to underlying activation of the haemostatic system and anti-cancer therapy inducing a hypercoagulable state. The diagnosis of PE on F-FDG PET/CT is challenging, particularly in the absence of intravenous contrast.