Arterial Occlusion in Takayasu Arteritis Detected as a Blood Pool Defect on 18 F-FDG Semiconductor PET/CT.

A 75-year-old woman with Takayasu arteritis was referred to 18 F-FDG PET/CT due to elevated C-reactive protein in her laboratory data. FDG PET/CT with semiconductor detectors revealed no uptake in the arterial walls, suggesting active inflammation. However, the blood pool uptake in the proximal portion of the left subclavian artery was defective, suggesting arterial occlusion. Magnetic resonance angiography revealed complete occlusion of the left subclavian artery. Ultrasonography showed the reverse flow of the left vertebral artery. Semiconductor PET can visualize the blood pool defects of the intra-arterial uptake in the arterial branches from the aorta.