18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Assessment of Occult Involvement in Widespread Granulomatosis with Polyangiitis (Wegener's Granulomatosis).

Granulomatosis with polyangiitis (GPA) can be classified as classic triad of organ involvement consisting of lungs, upper respiratory tract/sinuses, and kidneys; limited which is not having the full triad; or widespread with additional organ involvement for example prostate, spleen, skin, eyes or peripheral nervous system and occasionally other organs. GPA is associated with increased 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT). PET/CT has the advantages of whole-body imaging and detecting metabolic abnormality before structural changes.

Dual time point fluorodeoxyglucose positron emission tomography/computed tomography in differentiation between malignant and benign lesions in cancer patients. Does it always work?

Objectives: Assess the added value of dual time point F-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP F-18-FDG-PET/CT) in the differentiation of malignant from a benign lesion in cancer patients.

Materials And Methods: Totally, 140 F-18-FDG PET/CT scans of 60 cancer patients who underwent DTP protocol (early whole body PET/CT [E] at 60 min [range, 45-76 min] and delayed limited PET/CT [D] on areas of interest at 120 min [range, 108-153 min] after the tracer injection) were retrospectively reviewed. Visual and semi-quantitative analysis was performed on both early and delayed images.