Venous thromboembolism: A novel application for 18F-FDG-PET/CT

Abstract

Learning Objectives: 1. Provide basic knowledge of venous thromboembolism (VTE). 2. Acknowledge that the diagnosis of VTE is challenging due to a vague and unspecific clinical presentation resembling other conditions, and less-than-perfect standard imaging strategies. 3. Evaluate the basis for 18F-FDG-PET/CT whole-body assessment of VTE, i.e. the intimate link between thrombosis and inflammation. 4. Assess the different areas where the use of FDG as a marker of the inflammatory component of VTE may contribute to patient management.

VTE is a common and potentially fatal disease comprising interrelated clinical entities including deep venous thrombosis (DVT) and pulmonary embolism (PE), but it may occur globally in the venous vasculature, not just as DVT or PE. This promotes the use of a whole-body 18F-FDG-PET/CT scans providing in addition sensitive screening for underlying malignancies as cause of novel VTE. Several studies, including some from our groups, have shown DVT to be highly FDG-avid at very early, even pre-symptomatic, stages, also in patients suspected of only PE which tends to be less FDG-avid. FDG may also provide a desirable quantitative measure of global disease activity for monitoring disease course and treatment response. Furthermore, VTE patients are prone to relapse, but the morphologic changes which are the basis of current diagnostic methods may remain unchanged for years. Thus, FDG-avidity is a marker of metabolically active, treatment-demanding novel VTE, whereas non-avidity characterizes metabolically inactive chronic VTE, which is better served by a more conservative approach. In conclusion, further studies are needed, but evidence is emerging for VTE as a novel clinical application for 18F-FDG-PET/CT imaging.