Ultrasensitive, high-resolution, extended-field-of-view total-body (TB) PET using the first-of-its-kind 194-cm axial-field-of-view uEXPLORER may facilitate the interrogation of biologic hallmarks of hitherto difficult-to-evaluate low-signal vessel wall pathology in cardiovascular disease. Methods: Healthy volunteers were imaged serially for up to 12 h after a standard dose of ¹⁸F-FDG (n = 15) or for up to 3 h after injection of a very low dose (about 5% of a standard dose; n = 15). A cohort undergoing standard ¹⁸F-FDG PET (n = 15) on a conventional scanner with a 22-cm axial field of view served as a comparison group. Arterial wall signal, crosstalk with hematopoietic and lymphoid organs, and image quality were analyzed using standardized techniques. Results: TB PET depicted the large vessel walls with excellent quality. The arterial wall could be imaged with high contrast up to 12 h after tracer injection. Ultralow-dose TB ¹⁸F-FDG images yielded a vessel wall signal and target-to-background ratio comparable to those of conventional-dose, short-axial-field-of-view PET. Crosstalk between vessel wall and lymphoid organs was identified with better accuracy in both TB PET cohorts than in conventional PET. Conclusion: TB PET enables detailed assessment of in vivo vessel wall biology and its crosstalk with other organs over an extended time window after tracer injection or at an ultralow tracer dose. These initial observations support the feasibility of serial imaging in low-risk populations and will stimulate future mechanistic studies or therapy monitoring in atherosclerosis and other vessel wall pathologies.

使用首个 194 厘米轴向视场 uEXPLORER 的超灵敏、高分辨率、扩展视场全身 (TB) PET 可能有助于探查迄今为止困难的生物特征-评估心血管疾病中的低信号血管壁病理学。方法：健康志愿者在注射标准剂量¹⁸ F-FDG ( n  = 15) 后长达 12 小时或注射极低剂量（约标准剂量的 5%；n  = 15）。 在具有 22 厘米轴向视野的传统扫描仪上接受标准¹⁸ F-FDG PET（n = 15）的队列作为对照组。使用标准化技术分析动脉壁信号、造血和淋巴器官的串扰以及图像质量。结果： TB PET 清晰地描绘了大血管壁。注射示踪剂后 12 小时内可以对动脉壁进行高对比度成像。超低剂量 TB ¹⁸ F-FDG 图像产生的血管壁信号和目标背景比与传统剂量、短轴视场 PET 相当。在两个 TB PET 队列中，比传统 PET 更准确地识别出血管壁和淋巴器官之间的串扰。结论： TB PET 能够在示踪剂注射后的较长时间窗口内或以超低示踪剂剂量详细评估体内血管壁生物学及其与其他器官的串扰。这些初步观察结果支持了低风险人群中连续成像的可行性，并将刺激未来动脉粥样硬化和其他血管壁病理的机制研究或治疗监测。