Introduction 1 2 3 18 d 4 5 6 Case report A 60-year-old Caucasian woman was admitted to the hospital with a 4-month history of excessive fatigue, coughing, anorexia and weight loss, night sweats, and atypical chest pain. She also experienced short periods of fever. She experienced headaches and ear pain and hearing loss for over the last month, mainly on the left side, and felt sometimes dizzy. No blurred vision complaints or eye problems were noted. She was not known with any allergies. l The family history revealed a daughter with systemic lupus erythematosus. Physical examination revealed a pulse of 104, and bloodpressure was 125/85 mmHg and the temperature 37.1°C. Heart sounds were normal, and the lungs were clear. The outer ears were normal. No lymphadenopathy was detected and no scalp tenderness or decreased pulsation at the temporal arteries was noted. Laboratory tests revealed an erythrocyte sedimentation rate (ESR) of 51 mm/h and C-reactive protein (CRP) of 53 mg/L. Test for rheumatoid factor was 42 kU/L (<10), and tests for antinuclear facor and double-stranded DNA antibodies were negative. A test for anti-neutrophil cytoplasmic antibody (ANCA) appeared to be myeloperoxidase positive with p-ANCA specificity. Serum electrolytes and creatinine were normal. Her differential blood count, alkaline phosphatase, and transaminases were normal. The urine gave a negative test for protein, and the sediment contained no white cells, red cells, or casts in the urine. 1 Fig. 1 a b c  After placing inner ear tubes, her hearing loss improved only little. Culture of the ear secretion was negative for pathogenic microorganisms. Audiograms confirmed sensorineural hearing loss, particularly in the left ear. Investigation of the eyes revealed no abnormalities, especially no keratitis. Therapy was started with three cycles of 1,000 mg methylprednisolon intravenously and later 60 mg prednisolon daily orally. Her general condition and hearing loss improved subjectively. Audiograms 6 weeks later showed also objective improvement of hearing. A control CT scan showed improvement of the abnormalites in both mastoid regions. As a consequence of the high doses of steroids, risedronate and calcium supplementation were started, and also methothrexate was added for the reason of its steroid-sparing effect. “Atypical” Cogan’s syndrome was diagnosed on the basis of sensorineural deafness with improvement on steroids and large-vessel vasculitis of the aortic arch. 9 9 A third PET/CT showed higher pathological activity, compared to the first PET/CT, in the wall of the aortic arch and in the perivascular space adjacent to the truncus pulmonalis (the SUV max was12.9 compared to the SUV max of 11.9 of the first pretherapy PET/CT investigation). Consequently, the dose of methothrexate and prednisone were both increased to 20 mg/day. Discussion 7 8 9 10 11 12 13 The conclusion seems justified that F18-FDG-PET/CT is helpful in risk assessment of large-vessel vasculitis, as it provides intrinsically fused morphologic and functional data in a single examination.