Aortic wall inflammation due to Takayasu arteritis imaged with 18F-FDG PET coregistered with enhanced CT.
The purpose of this study was to evaluate the ability of (18)F-FDG PET to identify aortitis and to localize and follow disease activity in patients with Takayasu arteritis. The value of using (18)F-FDG PET coregistered with enhanced CT in determining vascular lesion sites and inflammatory activity was assessed.


METHODS
Takayasu arteritis was diagnosed according to the predefined criteria. Eleven patients with Takayasu arteritis in the active stage, 3 patients with Takayasu arteritis in the inactive stage, and 6 healthy subjects underwent (18)F-FDG PET coregistered with enhanced CT and the inflammatory vascular lesion was evaluated by using the standardized uptake value (SUV) of (18)F-FDG accumulation as an index. Two patients with active disease were analyzed by sequential (18)F-FDG PET scans during treatment.


RESULTS
The (18)F-FDG PET revealed intense (18)F-FDG accumulation (SUV > or = 2.7) in the vasculature of 2 of the 11 cases in the active stage of Takayasu arteritis. The other 9 patients in the active stage revealed weak (18)F-FDG accumulation (2.3 > or = SUV > or = 1.2). No significant (18)F-FDG accumulation was observed in the patients with inactive disease (SUV < or = 1.2) and 6 control healthy subjects (SUV < 1.3). Given the cutoff SUV is 1.3, the sensitivity of (18)F-FDG PET analysis of Takayasu arteritis is 90.9% and the specificity is 88.8%. (18)F-FDG PET coregistered with enhanced CT localized (18)F-FDG accumulation in the aortic wall in the patients with Takayasu arteritis who had weak (18)F-FDG accumulation that could not otherwise be identified anatomically. Finally, (18)F-FDG accumulation resolved with therapy in 2 active cases. The disappearance of (18)F-FDG accumulation did not coincide with the level of general inflammatory markers.


CONCLUSIONS
The (18)F-FDG PET images coregistered with enhanced CT images showed the distribution and inflammatory activity in the aorta, its branches, and the pulmonary artery in patients with active Takayasu arteritis, even those who had weak (18)F-FDG accumulation. The intensity of accumulation decreased in response to therapy.
Kobayashi
Yasushi
Y
Department of Internal Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Ishii
Kenji
K
Oda
Keiichi
K
Nariai
Tadashi
T
Tanaka
Youji
Y
Ishiwata
Kiichi
K
Numano
Fujio
F
D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging; D001025:Aortitis / Q000000981:diagnostic imaging* / Q000209:etiology; D001027:Aortography; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013625:Takayasu Arteritis / Q000150:complications / Q000000981:diagnostic imaging*; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18