Fludeoxyglucose positron emission tomography in the diagnosis of giant cell arteritis

We describe a case in which fludeoxyglucose F18 positron emission tomograph y (PET) led directly to the diagnosis of giant cell arteritis in an elderly woman with a fever of unknown origin. The patient presented with a 3-month history of fatigue, fever, headache, visual disturbance, jaw claudication, and anemia. A computed tomographic scan showed an anterior mediastinal mas s that was suspected of being malignant. A fludeoxyglucose F 18 PET scan pe rformed for preoperative evaluation identified striking uptake of fludeoxyg lucose F 18 in the walls of the entire aorta, left main coronary artery, an d sub-clavian, carotid, and common iliac arteries bilaterally, suggestive o f an arteritis, a diagnosis subsequently confirmed by the findings of an ar terial biopsy. Her erythrocyte sedimentation rate was 129 mm/h. There was n ormalizaton of the PET scan 2 weeks following treatment with prednisolone. This case suggests that fludeoxyglucose F 18 PET contributes to the noninva sive diagnosis of giant cell arteritis, as well as to the evaluation of the extent of disease, response to therapy, and disease recurrence.