Impact of previous glucocorticoid therapy on diagnostic accuracy of [18F] FDG PET-CT in giant cell arteritis

• Published in: Seminars in arthritis and rheumatism 2023-06, Vol.60, p.152183-152183, Article 152183
• Main Authors: Narváez, J., Estrada, P., Vidal-Montal, P., Sánchez-Rodríguez, I., Sabaté-Llobera, A., Nolla, J.M., Cortés-Romera, M.
• Format: Article
• Language: English
• Subjects: 18F-FDG PET-CT; Diagnostic accuracy; Fluorodeoxyglucose F18 - therapeutic use; Giant cell arteritis; Giant Cell Arteritis - diagnostic imaging; Giant Cell Arteritis - drug therapy; Glucocorticoid therapy; Glucocorticoids - therapeutic use; Humans; Methylprednisolone - therapeutic use; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals - therapeutic use; Retrospective Studies; Vascular wall uptake of FD
• ISSN: 0049-0172; 1532-866X
• DOI: 10.1016/j.semarthrit.2023.152183

To evaluate the impact of prior glucocorticoid (GC) treatment on the diagnostic accuracy of 18F-FDG PET-CT in giant cell arteritis (GCA). Retrospective study of a consecutive cohort of 85 patients with proven GCA who received high-dose GC before PET-CT. Thirty-nine patients previously treated with methylprednisolone (MP) boluses, of whom 37% were PET-CT (uptakes grade 3 or 2) positive. The positivity rate was 80% with MP doses of 125 mg, 33% with 250 or 500 mg, and 0% with doses of 1 g.  If we also classify as positive those cases with a grade 1 uptake (with a circumferencial uptake and smooth linear or long segmental pattern, possibly indicative of “apparently inactive” vasculitis), the positivity rate increases to 62% (100%, 50–60%, and 33% for the different MP doses, respectively). In patients with new-onset GCA treated with high-dose oral GC, PET-CT positivity was 54.5% in patients treated for less than two weeks, 38.5% in those treated for 2 to 4 weeks, and 25% in those treated for 4 to 6 weeks (increasing to 91%, 77%, and 50%, respectively, if we include cases with grade 1 uptake and these characteristics). In patients with relapsing/refractory GCA, or who developed GCA having a prior history of PMR, PET-CT positivity reached 54% despite long-term treatment with low-to-moderate doses of GC (68% including cases with a grade 1 uptake). A late 18F-FDG PET-CT (beyond the first 10 days of treatment) can also be informative in a considerable percentage of cases.