Although older studies argue that FDG PET/CT cannot demonstrate inflammation in cranial arteries, e.g. temporal and maxillary arteries, the resolution of modern PET systems may have improved, making a case for FDG PET/CT. FDG PET/CT is increasingly used in giant cell arteritis (GCA) diagnosis due to its excellent diagnostic accuracy considering large-vessel involvement. In case of uncommon distribution of vessel involvement or marginally increased large-vessel FDG uptake, FDG PET/CT-specificity may be compromised. Hence, recognising FDG uptake in cranial arteries potentially adds to FDG PET/CTs diagnostic accuracy.~Objectives To evaluate the diagnostic accuracy of conventional FDG PET/CT of the cranial arteries in the diagnosis of GCA.~Methods In a cohort of consecutively included glucocorticoid-naïve patients suspected of new-onset GCA, patients with a clinical GCA diagnosis will be identified. Conventional FDG PET/CT and vascular ultrasound(US) was performed before treatment. Patients were referred for a temporal artery biopsy (TAB).~Controls are age-(+/- 3 years) and sex-matched malignant melanoma (MM) patients who had a follow-up metastatic-disease-free FDG PET/CT ≥6 months after MM resection.~Images will be assessed by 5 nuclear medicine physicians blinded to clinical symptoms and findings. Temporal (TA), maxillary (MA) and vertebral (VA) arteries will be visually assessed. Arterial FDG uptake more than FDG uptake in surrounding tissue is considered positive. Sensitivity, specificity and interreader agreement will be evaluated.
A case-control study to evaluate the diagnostic accuracy of FDG uptake in cranial arteries by FDG PET/CT in the diagnosis of giant cell arteritis.