Martínez–Rodríguez I, et al. – The accuracy and role of ¹⁸F–FDG PET/CT were examined in the follow–up of patients with large–vessel vasculitis (LVV). In investigations, ¹⁸F–FDG PET/CT seemed to be useful in the follow–up of LVV.

Methods

• This study consisted of 37consecutive patients (28 women, 66.5±9.9 y.) with an initial ¹⁸F–FDG PET/CT positive for LVV and a mean±standard deviation follow–up PET/CT of 7.5±2.9 months after the initial scan.
• A semiquantitative analysis of aortic wall uptake was performed calculating the target–to–background ratio (TBR: aortic wall uptake divided by blood pool uptake).
• In investigations, the initial and follow–up TBR as well as the clinical and laboratory outcome were compared.

Results

• Overall, the mean TBR decreased from 1.7±0.5 at the initial scan to 1.5±0.3 at the time of follow–up (p=0.0001).
• In the 21 patients who experienced clinical improvement following therapy the TBR also decreased from 1.8±0.6 to 1.5±0.3 (p=0.0002).
• However, in the other 16 patients, in whom the treating physician considered that there was no clinical improvement following therapy, no statistically significant differences in TBR were found when data from the first and the follow–up PET/CT scans were compared (1.6±0.3 vs. 1.5±0.3, p=0.1416).
• Non–statistically significant higher TBR was observed at the time of disease diagnosis, in patients who experienced clinical improvement following therapy (1.8±0.6 versus 1.6±0.3; p=0.12).