Background: The observation that 2-deoxy-2[18F]fluoro-D-glucose-positron emission tomography/magnetic resonance imaging ([18F]F-FDG-PET/MRI) revealed high-grade arterial wall FDG uptake, without arterial wall thickening with contrast-enhancement, in a considerable number of c-TA patients in our previous study, encouraged us to compare patients with both PET and MR angiography (MRA) positives, with those with PET positive but MRA negative. Our aim was to evaluate the relevance of these two imaging modalities together.
Methods: A three-center cross-sectional study with 17 patients who fulfilled the EULAR/PRINTO/PReS criteria for c-TA and who underwent [18F]F-FDG-PET/MRI was previously performed. Herein we compared patients/vessels with positive PET (arterial wall 18F-FDG uptake higher than liver) and positive MRA (arterial wall thickening with contrast-enhancement)-group 1, with those with positive PET but negative MRA-group 2.
Results: Median disease duration of 17 c-TA patients was 10.4 years. Nine patients were classified as group 1 and six as group 2. Median of metabolic inflammatory volume (MIV) of all arterial segments was significantly higher in group 1 (2346 vs. 1177 cm3; p = 0.036). Fifty-four (19%) from 284 available arterial segments presented positive findings in vessel wall in one or both images. Positive findings were concordant between PET and MRA in only 13% arterial segments (group 1); most changes (28-59.6%) that were discordant between both images, were positive in PET and negative in MRA (group 2).
Conclusion: Our study demonstrated that [18F]F-FDG-PET/MRI added information about inflammation in vessel wall of c-TA patients. Prospective multicenter studies are needed in order to get solid data to guide immunosuppressive tapering and withdrawal.
Keywords: Adolescents; Children; PET; PET/MRI; Takayasu arteritis; Vasculitis.
© 2022. The Author(s).