Diagnosis of Brachiocephalic Thrombophlebitis as the Cause of Fever of Unknown Origin by 18F-FDG-PET/CT

Abstract

Fever of unknown origin (FUO) represents a challenge in diagnosis and treatment. The role of 18Ffluorodeoxyglucose positron emission tomography (FDG-PET) / computed tomography (CT) in the differential diagnosis of this entity is presently well established. We report the case of a patient with infectious/inflammatory symptoms but no evident localization and subsequent relapse, in which PET/CT showed its ability to not only determine the exact localization of a thrombophlebitic focus as cause of FUO, but also to monitor and determine the success of treatment. After performing a FDG-PET/CT and detecting a thrombophlebitis in the brachiocephalic vein, low molecular heparins were introduced in the course of therapy. Soon (about 24 hours) thereafter, clinical symptoms significantly decreased and could no longer be observed. After continuing the antibiotic and anticoagulant therapy for 4 weeks, a follow-up PET/CT scan was performed. That scan no longer showed abnormal uptake in the previous intravascular localization. Consequently, we suggest that PET/CT is a diagnostic modality feasible to identify and monitor therapy response of intravascular thrombophlebitic foci.

FDG-PET/CT in venous thromboembolism

“…More than half of DVTs occur in calf veins or pelvic veins, where ultrasonography has limited sensitivity and none of the above mentioned techniques address vessels outside the pulmonary and proximal femoral vasculature. FDG-PET/CT provides whole-body assessment, and a mounting number of case reports demonstrate sightings of venous activity consistent with VTE in venous vasculature throughout the body and in various clinical settings: lower extremity veins [24][25][26][27][28], iliac vein [26], upper extremity veins [29][30][31], superior vena cava [32,33], inferior vena cava [34][35][36], portal vein [37,36], renal vein [34], jugular vein [38], brachiocephalic vein [33,39], indwelling catheters [40][41][42], superior sagittal sinus [43,33], pulmonary embolism (including supposed microembolism from injection artefacts) [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], lung infarction [59][60][61], right-heart...…”