Aortic ¹8F-FDG uptake in patients suffering from granulomatosis with polyangiitis.

ABSTRACT

PURPOSE: The objective of the study was to systematically assess aortic inflammation in patients with granulomatosis with polyangiitis (GPA) using (18)F-2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET)/CT. METHODS: Aortic inflammation was studied in PET/CT scans obtained from 21 patients with GPA; 14 patients with sarcoidosis were included as disease controls, 7 patients with stage I or II head and neck carcinoma ascertained during routine clinical practice were used as healthy controls (HC) and 5 patients with large vessel vasculitis (LVV) were used as positive controls. Aortic (18)F-FDG uptake was expressed as the blood-normalized maximum standardized uptake value (SUVmax), known as the target to background ratio (mean TBRmax). RESULTS: The mean TBRmax (interquartile range) of the aorta in patients with GPA, sarcoidosis, HC and LVV were 1.75 (1.32-2.05), 1.62 (1.54-1.74), 1.29 (1.22-1.52) and 2.03 (1.67-2.45), respectively. The mean TBRmax was significantly higher in patients suffering from GPA or LVV compared to HC (p < 0.05 and p < 0.005, respectively) and tended to be higher in patients suffering from sarcoidosis, but this did not reach statistical significance (p = 0.098). The mean TBRmax of the most diseased segment was significantly higher compared to HC [1.57 (1.39-1.81)] in LVV patients [2.55 (2.22-2.82), p < 0.005], GPA patients [2.17 (1.89-2.83), p < 0.005] and patients suffering from sarcoidosis [2.04 (1.88-2.20), p < 0.05]. In GPA patients, the mean TBRmax of the aorta was significantly higher in patients with previous renal involvement [2.01 (1.69-2.53)] compared to patients without renal involvement in the past [1.60 (1.51-1.80), p < 0.05]. Interrater reproducibility with a second reader was high (all intraclass correlation coefficients >0.9). CONCLUSION: Patients suffering from GPA show marked aortic FDG uptake.