Translocator Protein 18 kDa–Targeted Total-Body PET Imaging Reveals Immune-Specific Vascular Inflammation in Large-Vessel Vasculitis: A Prospective Head-to-Head Comparison with 18 F-FDG

作者：Min Zhang, Jingyi Qian, Yingqi Jia, Shuyi Yu, Yuying Fan, Haoyu Pan, Xiaohan Wei, Zhixia Yang, Shiyan Gu, Jingyi Wu, Tiancheng Zhou, Yue Wang, Jin Wang, Yi Chen, Jialin Teng, Chengde Yang, Biao Li, Hui Shi · 发表于：Journal of Nuclear Medicine · 年份：2025 · DOI：10.2967/jnumed.125.270910 · 被引用次数：2 · 研究领域：Vasculitis and related conditions、Systemic Sclerosis and Related Diseases、Chemokine receptors and signaling

Accurate assessment of vascular inflammation in large-vessel vasculitis (LVV) remains challenging, especially in patients with normal inflammatory markers or inconclusive 18 F-FDG PET findings. The translocator protein 18 kDa (TSPO), a marker of inflammatory process, has emerged as a promising molecular target for imaging vascular inflammation in LVV. Methods: We prospectively enrolled 11 treatment-naïve patients with LVV and 11 healthy controls who underwent 90-min dynamic total-body 18 F-DPA714 PET/CT imaging. Ten patients also underwent 18 F-FDG PET/CT for direct comparison. We assessed SUVs, lesion-to-background ratios, and kinetic parameters using a 2-tissue compartment model (2T4K_vB). Peripheral blood samples from patients and controls were analyzed by flow cytometry to characterize the cellular sources of the TSPO signal. Results: 18 F-DPA714 PET revealed that tracer uptake in patients with LVV was significantly higher than that in healthy controls (median SUV mean , 0.81 [interquartile range (IQR), 0.64–0.98] vs. 0.54 [IQR, 0.44–0.64]; P = 0.000–0.043). Kinetic modeling using the 2T4K_vB compartment model further confirmed the specificity of TSPO binding, demonstrating elevated parameters of irreversible binding and total distribution volume in inflamed vascular segments. In head-to-head comparisons, 18 F-DPA714 showed modestly but significantly higher vessel wall–to–lumen contrast relative to 18 F-FDG (lesion-to-background ratio, 1.02 [IQR, 1.00–1.15] vs....