Turkish Journal of Medical Sciences




The aim of this study is to evaluate the baseline F18-FDG PET/CT findings of individuals diagnosed with giant cellarteritis (GCA) and to explore its association with clinical findings and classification criteria.Materials and methods: We analysed data from patients who underwent F18-FDG PET/CT scans to investigate large vessel (LV)involvement between 2010 and 2019. Only patients with a clinical diagnosis of GCA and at least 6 months of follow-up were included.We compared initial clinical features and laboratory findings based on the presence of LV vasculitis on PET/CT and the maximumstandard uptake value (SUVmax) of vascular territories.Results: Twenty-nine patients (median age at diagnosis: 70, F/M: 24/5) were included in the study. Among them, 21 patients (72.4%)presented with cranial symptoms, while 8 patients (27.5%) had isolated LV-GCA. Twenty-two patients (75.9%) met the ACR/EULAR2022 GCA classification criteria. LV vasculitis was detected on PET/CT in 23 patients (79.3%). A positive correlation was observedbetween SUVmax in the thoracic aorta and both CRP and ESR levels (r = 0.50, p = 0.026 and r = 0.63, p = 0.002, respectively). PET/CTpositive patients were found to be younger (p = 0.016) and more frequently female (p = 0.017). They also exhibited fewer headaches(56.5% vs. 100%, p = 0.04), experienced fewer flares during follow-up (p = 0.03), and had a lower cumulative glucocorticoid dose at the6th month (p = 0.036). Comparison of PET/CT-positive patients (n = 23) based on the fulfilment of the ACR/EULAR 2022 classificationcriteria revealed that patients who met these criteria were older (p = 0.02) and had significantly lower CRP levels at diagnosis (p = 0.02).Conclusion: The performance of F18-FDG PET/CT in diagnosing LV involvement in GCA is favourable, and the severity of FDGuptake in the vessel wall correlates with the acute phase response. Patients with extracranial involvement on PET/CT exhibit distinctfeatures, including a younger age and female predominance. Additionally, these patients appear to experience fewer relapses and requirelower doses of glucocorticoids. However, the clinical significance of PET/CT in patients who met ACR/EULAR classification criteria,predominantly consisting of patients with ischemic cranial symptoms, could not be determined in our study.


Giant cell arteritis, large vessel vasculitis, positron emission tomography

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