PT  - JOURNAL ARTICLE
AU  - Alison H.  Clifford
AU  - Elana M.  Murphy
AU  - Steven C.  Burrell
AU  - Mathew P.  Bligh
AU  - Ryan F.  MacDougall
AU  - J. Godfrey  Heathcote
AU  - Mathieu C.  Castonguay
AU  - Min S.  Lee
AU  - Kara Matheson
AU  - John G.  Hanly
TI  - Positron Emission Tomography/Computerized Tomography in Newly Diagnosed Patients with Giant Cell Arteritis Who Are Taking Glucocorticoids
AID  - 10.3899/jrheum.170138
DP  - 2017 Sep 15
TA  - The Journal of Rheumatology
PG  - jrheum.170138
4099  - http://www.jrheum.org/content/early/2017/09/11/jrheum.170138.short
4100  - http://www.jrheum.org/content/early/2017/09/11/jrheum.170138.full
AB  - Objective Large vessel uptake on positron emission tomography/computerized tomography (PET/CT) supports the diagnosis of giant cell arteritis (GCA). Its value, however, in patients without arteritis on temporal artery biopsy and in those receiving glucocorticoids remains unknown. We compared PET/CT results in GCA patients with positive (TAB+) and negative temporal artery biopsies (TAB–), and controls. Methods Patients with new clinically diagnosed GCA starting treatment with glucocorticoids underwent temporal artery biopsy and PET/CT. Using a visual semiquantitative approach, 18F-fluorodeoxyglucose (FDG) uptake was scored in 8 vascular territories and summed overall to give a total score in patients and matched controls. Results Twenty-eight patients with GCA and 28 controls were enrolled. Eighteen patients with GCA were TAB+. Mean PET/CT scores after an average of 11.9 days of prednisone were higher in patients with GCA compared to controls, for both total uptake (10.34 ± 2.72 vs 7.73 ± 2.56; p = 0.001), and in 6 of 8 specific vascular territories. PET/CT scores were similar between TAB+ and TAB– patients with GCA. The optimal cutoff for distinguishing GCA cases from controls was a total PET/CT score of ≥ 9, with an area under the receiver-operating characteristic curve of 0.75, sensitivity 71.4%, and specificity 64.3%. Among patients with GCA, these measures correlated with greater total PET/CT scores: systemic symptoms (p = 0.015), lower hemoglobin (p = 0.009), and higher platelet count (p = 0.008). Conclusion Vascular FDG uptake scores were increased in most patients with GCA despite exposure to prednisone; however, the sensitivity and specificity of PET/CT in this setting were lower than those previously reported.