Three days of high-dose glucocorticoid treatment attenuates large-vessel 18F-FDG uptake in large-vessel giant cell arteritis but with a limited impact on diagnostic accuracy
To evaluate the in-treatment diagnostic accuracy of FDG PET/CT in large-vessel giant cell arteritis (LV-GCA) by serial scans before and after a short course of high-dose glucocorticoid treatment.
Twenty-four glucocorticoid-naïve patients with new-onset PET/CT verified LV-GCA (pre-treatment baseline PET) were prospectively included. Excluded were patients with a previous history of GCA or polymyalgia rheumatica, LV-GCA-mimicking conditions and patients on immunosuppressive therapy. All patients were treated with 60 mg of oral prednisolone daily and assigned for in-treatment FDG PET/CT after either 3 (PET3) or 10 days (PET10). Two experienced nuclear medicine physicians, blinded to patients’ clinical data, reviewed the FDG PET/CT images. A visual semi-quantitative approach was used. Segmental and homogenous FDG uptake in the wall of the aorta and/or supra-aortic branches with higher uptake intensity than liver was considered consistent with vasculitis. Inter-reader reliability was evaluated.
Although glucocorticoid treatment attenuated FDG uptake in large vessels, LV-GCA was accurately diagnosed in 10/10 patients after 3 days of treatment, but only in 5/14 patients after 10 days of treatment (p < 0.001). Interrater reliability was substantial (agreement 87%, Cohen’s weighted kappa 0.70). No correlation between CRP and FDG uptake was found.
Within 3 days of high-dose glucocorticoid treatment, FDG PET/CT can diagnose LV-GCA with high sensitivity. This window of opportunity ensures that prompt glucocorticoid treatment can be initiated to avoid debilitating GCA complications with a limited effect on diagnostic accuracy. After 10 days of treatment, FDG PET/CT sensitivity decreases significantly.
KeywordsGiant cell arteritis Large-vessel vasculitis Diagnosis Glucocorticoids 18F-FDG PET/CT
This work was funded by The Danish Rheumatism Association, Aarhus University, Aarhus University Hospital, Brødrene Hartmann Fond, A.P. Moeller Foundation, Aase & Ejnar Danielsen Foundation. We would like to thank Stine Kramer, MD, Nuclear Medicine and PET Centre, Aarhus University Hospital for scoring of in-treatment PET scans for reliability test; Aparna Udupi, statistician, Faculty of Health, Aarhus University for statistical advice; Morten Pilegaard, Associate Professor, Department of Business Communication, Aarhus University; Partner, Termshare A/S, Denmark and Anne-Birgitte Blavnsfeldt, MD, Department of Rheumatology, Aarhus University Hospital for editing the manuscript.
The views expressed in the submitted article are the authors’ own and not an official position of the institution or funder.
This study was funded by The Danish Rheumatism Association, Aarhus University, Aarhus University Hospital, Brødrene Hartmann Foundation, A.P. Moeller Foundation, Aase & Ejnar Danielsen Foundation.
Compliance with ethical standards
All procedures performed in the study were in accordance with the ethical standards of the National Committee on Health Research Ethics and with the 1964 Helsinki Declaration and its later amendments.
The Central Denmark Region Committees on Health Research Ethics (reference number 1–10–72-60-1) and The Danish Data Protection Agency (reference number 1–16–02-380-1) approved the study.
Informed consent was obtained from all individual participants included in the study.
Conflicts of interests
Ellen-Margrethe Hauge has received fees for speaking from MSD, AbbVie, UCB and Sobi; and received research funding to Aarhus University Hospital from Roche and Novartis.
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