This lecture presents the case of a 21-year-old male with fever of unknown origin and persistent back pain. Despite prior CT and MRI scans showing no abnormalities, FDG PET/CT revealed characteristic vascular uptake patterns highly suggestive of large-vessel vasculitis.

Through systematic review of whole-body PET/CT, this lecture highlights the strengths of hybrid imaging in identifying inflammatory aortitis, interpreting uptake intensity relative to mediastinal and hepatic activity, and integrating findings into the differential diagnosis of systemic autoimmune and inflammatory disease.

Learning Objectives

By the end of this lecture, participants will be able to:

• Recognize the PET/CT appearance of aortitis, including circumferential vascular wall uptake exceeding mediastinal blood pool and liver activity.
• Apply visual grading criteria to assess the intensity of vascular uptake in suspected vasculitis.
• Differentiate patterns of large-vessel vasculitis (e.g., Takayasu arteritis) from other inflammatory or infectious conditions.
• Understand the importance of whole-body PET/CT in systemic disease evaluation, including review of pulmonary and skeletal structures.
• Identify common pitfalls, including false negatives in patients on corticosteroid therapy, and the need for appropriate preparation prior to imaging.