Clinical usefulness of 18FFDG-PET/CT for the assessment of disease activity of Takayasu arteritis : A case report.

Abstract

A 14-year-old girl suspected as having Takayasu arteritis（TA） with hypertension found by chance in workplace experience was referred to us. 18Ffluorodeoxy glucose positron emission tomography （18FFDG-PET） revealed FDG uptakes in the aortic arch and bilateral internal carotid artery, even though serological inflammation markers including CRP and ESR were all negative. Oral prednisolone （PSL）（30mg/day） was started, and her clinical symptoms disappeared. One month after starting PSL, FDG uptake on 18FFDG-PET remained significant, even though the patient had no symptoms with negative inflammation markers. After tapering the PSL dosage to 20mg/day, the patient showed exacerbation of disease. The dose of PSL was increased to 25mg/day, and tacrolimus was added. Although the exacerbation had ceased, the patient clinically relapsed again after tapering the PSL dosage to 22.5mg/day. Tocilizumab was added. Subsequently, remission was achieved and maintained with 4mg/day of PSL. Serological inflammation markers are useful for the assessment of disease activity in TA. However, in some patients, inflammation markers remain negative even in active phase, making it difficult to assess disease activity. The 18FFDG-PET is useful for the assessment of disease activity even in such patients with no elevation of inflammatory markers in active phase of TA.