Positron Emission Computed Tomography Spectrum of Large Vessel Vasculitis in a Tertiary Center: Differences in 18F-fluorodeoxyglucose Uptake between Large Vessel Vasculitis with Predominant Cranial and Extracranial Giant Cell Arteritis Phenotypes

Abstract

(1) Objective:To assess the spectrum of PET-CT-related large vessel vasculitis (LVV) in a Spanish tertiary center and to determine whether FDG uptake by PET-CT differs between giant cell arteritis (GCA) with predominant cranial or extracranial phenotypes. (2) Methods: The spectrum of patients diagnosed with LVV by PET-CT in a tertiary referral hospital that cares for 450,000 people over a period of two years was reviewed. Moreover, differences in FDG uptake between LVV-GCA with predominantly cranial and extracranial phenotype were analyzed. (3) Results: Eighty patients were diagnosed with LVV by PET-CT. Most were due to systemic vasculitis (n = 64; 80%), especially GCA (n = 54; 67.5%). Other conditions included the presence of rheumatic diseases (n = 4; 3.2%), tumors (n = 9; 7.2%) and infections (n = 3; 2.4%). LVV-GCA patients with predominant extracranial GCA phenotype were younger (mean ± SD: 68.07 ± 9.91 vs. 75.46 ± 7.64 years; p = 0.017) and had a longer delay to the diagnosis (median [interquartile range] 12 [4–18] vs. 4 [3–8]; p = 0.006), but had polymyalgia rheumatica symptoms more frequently than those with predominantly cranial GCA phenotype (46.3% vs. 15.4%, p = 0.057). When FDG uptake was compared according to the two different disease patterns, no statistically significant differences were observed. However, patients with extracranial LVV-GCA showed a non-significantly higher frequency of vasculitic involvement of lower-extremity arteries. (4) Conclusions: Regardless of the predominant phenotype, LVV identified by PET-CT is more commonly due to GCA in the Spanish population. In these GCA patients, younger age, PMR, and a higher frequency of lower-extremity artery vasculitis suggest the presence of LVV.

Low incidence of malignancy in patients with suspected polymyalgia rheumatica or giant cell arteritis, examined with FDG-PET/CT

“…However, similar results were found in a recent study of patients with large vessel vasculitis, including GCA, on FDG-PET/CT. Tumors were found in 7.2% of the patients, though it is not reported whether these were all malignant or also included benign tumors ( 26 ).…”

18F-Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography Findings of Polymyalgia Rheumatica in Patients with Giant Cell Arteritis

“…Following this procedure, both grade 2 (considered as indicative) and grade 3 (considered as strongly) were estimated to be positive for the presence of LV vasculitis. Moreover, reevaluation of the positive 18F-PET-CT scans was conducted to confirm the results [22].…”

“…A retrospective study was conducted on patients undergoing 18F-FDG-PET-CT at the Fundación Jiménez Díaz University Hospital (Madrid, Spain) between April 2021 and March 2023. As reported, 54 of them were diagnosed with LV-GCA using 18F-FDG-PET-CT [22]. These 54 patients were evaluated for the presence of clinical and 18F-FDG-PET-CT features of PMR.…”

“…Fundación Jiménez Díaz University Hospital provides medical care to 450,000 people. Between April 2021 and March 2023, 1302 patients underwent PET-CT. As previously described [22], the Big Data Department of the Jiménez Díaz Foundation Hospital conducted a search for patients who underwent PET-CT during the two years of the study. In a further step, the 18F-PET-CTs of patients that included any of the following keywords: "vasculitis", "large vessels", "medium vessels", "vascular wall", "vascular", "aortitis", "vessel inflammation", "increased FDG vessel uptake", "polymyalgia rheumatica", and "giant cell arteritis" were evaluated by Rheumatology and Nuclear Medicine physicians.…”

“…18F-PET-CT scans were evaluated by experienced nuclear medicine physicians. They evaluated the distribution of the radiopharmaceutical in the aorta carotids, brachiocephalic trunk, subclavian, axillary, vertebral, humeral, iliac, and femoral arteries using a visual uptake classification scale as recently described [22]. In this regard, the standardized grading system ranged from 0 to 3 (vascular to hepatic uptake): following this procedure, the values obtained ranged from 0 = which meant no uptake (≤mediastinum); 1 = considered as low-grade uptake (<liver); 2 = intermediate-grade uptake (=liver), and 3 = defined as high-grade uptake (>liver).…”