To investigate the value of total-body PET/CT 2 h imaging with half-dose ¹⁸F-FDG in the detection of active lesions of Takayasu arteritis (TA).

Fifty-five patients with TA(13 males, 42 females, age: (34.3±13.9) years), who accepted 2 h total-body ¹⁸F-FDG PET/CT scan with half-dose activity in Zhongshan Hospital, Fudan University between January 2020 and June 2021, were retrospectively enrolled. TA was diagnosed according to the American College of Rheumatology (ACR) criteria. Patients were categorized into active TA group and inactive TA group based on the National Institutes of Health (NIH) criteria. Lesions with SUV_max≥(liver SUV_max- 0.1) were defined as active lesions. If multiple lesions occurred in one artery segment, only the lesion with the highest SUV_max was chosen. Lesion-to-blood SUV_max ratio was calculated. The independent-sample t test or Mann-Whitney U test was used to analyze the liver SUV_max, blood pool SUV_max and lesion-to-blood ratio between those 2 groups.

A total of 363 active lesions were found in 39 patients with active TA and 137 lesions were found in 16 patients with inactive TA. The liver SUV_max (1.93±0.45 vs 1.95±0.35; t=0.20, P=0.846) and blood pool SUV_max (0.75(0.63, 0.98) vs 0.90(0.77, 1.01); z=-1.45, P=0.148) of patients with active and those with inactive TA were not significantly different. The lesion-to-blood ratio in active TA group was higher than that in inactive TA group (3.09(2.36, 4.24) vs 2.57(2.24, 3.25); z=4.05, P<0.001).

Total-body PET/CT 2 h imaging has qualified lesion-to-blood ratio in TA imaging. Inflammatory lesions of vascular wall can be detected sensitively in both patients with active TA and those with inactive TA.

Takayasu arteritis; Whole body imaging; Positron-emission tomography; Tomography, X-ray computed; Fluorodeoxyglucose F18