Department of Nuclear Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany.
Department of Biostatistics, German Cancer Research Center, Heidelberg, Germany.
Sci Rep. 2023 Oct 19;13(1):17848. doi: 10.1038/s41598-023-43049-2.
Positron emission tomography with Gallium (Ga) labeled inhibitors of fibroblast activation protein (Ga-FAPI-PET) is a promising imaging technique for patients with recurrent pancreatic ductal adenocarcinomas (PDAC). To date, it is not clear if different acquisition timepoints for Ga-FAPI-PET may result in comparable imaging information and if repetitive Ga-FAPI-PET imaging may add diagnostic value to single timepoint acquisition for recurrent PDAC. Here we analyzed retrospectively early (20 min p.i.) and late (60 min p.i.) Ga-FAPI-PET imaging using FAPI-46 of 33 patients with possible recurrence of PDAC concerning detection rates and uptake over time of local recurrences, metastases, inflammatory lesions of the pancreas, cholestatic lesions of the liver and reactive tissue. 33 patients with histologically confirmed PDAC after complete or partial resection of the pancreas and possible recurrence were examined by Ga-FAPI-46-PET acquired 20- and 60-min post injection (p.i.) of the radiotracer. FAPI-positive lesions were classified as local recurrences, metastases, inflammatory lesions of the pancreas (ILP), cholestatic lesions of the liver and reactive tissue based on histology, PET- and CT-morphology and clinical information. Lesions were contoured, and standardized uptake values (SUVmax and SUVmean) and target-to-background ratios (TBR) were analyzed for both acquisition timepoints. In total, 152 FAPI-positive lesions (22 local relapses, 47 metastases, 26 inflammatory lesions of the pancreas, 28 reactive tissues, and 29 cholestatic lesions) were detected. Detection rates for the early and late acquisition of Ga-FAPI-46-PET were almost identical except cholestatic lesions, which showed a higher detection rate at early imaging. SUV parameters and TBRs of ILP significantly decreased over time. Cholestatic lesions showed a tendency towards decreasing uptake. All other types of lesions showed relatively stable uptake over time. Early and late acquisition of Ga-FAPI-PET results in comparable imaging information in patients with possible recurrence of PDAC. Two timepoint imaging offers additional diagnostic potential concerning differential diagnoses.
镓（Ga）标记的成纤维细胞激活蛋白（FAP）抑制剂正电子发射断层扫描（Ga-FAPI-PET）是一种有前途的成像技术，可用于复发性胰腺导管腺癌（PDAC）患者。迄今为止，尚不清楚 Ga-FAPI-PET 的不同采集时间点是否会导致可比的成像信息，以及重复 Ga-FAPI-PET 成像是否会为复发性 PDAC 的单次采集时间点增加诊断价值。在这里，我们回顾性分析了 33 例可能复发的 PDAC 患者的早期（注射后 20 分钟[pi]）和晚期（60 分钟 pi）Ga-FAPI-PET 成像，评估局部复发、转移、胰腺炎症病变、肝胆汁淤积病变和反应性组织的摄取率和随时间的变化。33 例经组织学证实的胰腺部分或完全切除后 PDAC 患者，在注射放射性示踪剂后 20-60 分钟行 Ga-FAPI-46-PET 检查。根据组织学、PET 和 CT 形态学以及临床信息，将 FAPI 阳性病变分类为局部复发、转移、胰腺炎症病变（ILP）、肝胆汁淤积病变和反应性组织。对两种采集时间点进行病变轮廓，并分析标准化摄取值（SUVmax 和 SUVmean）和靶背比（TBR）。总共检测到 152 个 FAPI 阳性病变（22 个局部复发，47 个转移，26 个胰腺炎症病变，28 个反应性组织和 29 个胆汁淤积病变）。除胆汁淤积病变外，早期和晚期 Ga-FAPI-46-PET 的检测率几乎相同，而胆汁淤积病变在早期成像中显示出更高的检测率。ILP 的 SUV 参数和 TBR 随时间显著降低。胆汁淤积病变的摄取有下降趋势。所有其他类型的病变在随时间推移时摄取相对稳定。在可能复发的 PDAC 患者中，早期和晚期 Ga-FAPI-PET 采集结果可提供可比的成像信息。双时间点成像为鉴别诊断提供了额外的诊断潜力。
