放射性核素药物18F-FAPI与18F-FDG在肝恶性肿瘤PET/CT显像中的应用比较

Comparison of the radionuclide drugs 18F-FAPI and 18F-FDG in PET/CT imaging of hepatic malignancies

关键词:  ₁₈^F-FAPI  ₁₈^F-FDG  肝脏恶性肿瘤  PET/CT  成纤维细胞激活蛋白

Key words:  _¹⁸F-Fibroblast Activation Protein Inhibitor  _¹⁸F-Fluorodeoxyglucose  Liver Neoplasms  Positron Emission Tomography-Computed Tomograph  Fibroblast Activation Protein

摘要:

目的 比较评价₁₈^{F-FAPI PET/CT}与₁₈^{F-FDG PET/CT}在肝脏恶性肿瘤中的诊断效能,对比分析两种显像剂的SUV_max诊断阈值,探讨其在肝脏恶性肿瘤中的诊断价值。方法 研究分析2023年2月至2023年7月于江南大学附属医院行₁₈^{F-FAPI-04 PET/CT}与₁₈^{F-FDG PET/CT}检查的20例患者(其中男性16例、女性4例,中位年龄65岁)的临床及影像资料。20例患者分别行₁₈^{F-FAPI-04 PET/CT}与^₁₈F-FDG PET/CT,显像间隔时间≤7天。入组病例以组织病理学作为最终诊断的金标准；对于组织诊断不适用的病例,以影像学随访判断是否存在肝脏恶性肿瘤。比较两种显像剂的PET/CT影像学表现,采用Wilcoxon signed-rank test比较₁₈^{F-FAPI PET/CT}与₁₈^{F-FDG PET/CT}显像二者SUV_max、MTV、LBR之间的差异性；通过Kappa检验评价两位观察者识别病灶区域的一致性；通过SUV_max[M(P25,75)]的Wilcoxon配对秩和检验评价1h、2h显像的图像对比度及相关性。以P＜0.05为差异或相关性有统计学意义。结果 ₁₈^{F-FAPI PET/CT}与₁₈^{F-FDG PET/CT}在18例阳性病变(原发性9例、转移性9例)的SUV_max分别为11.74(7.65,15.51)、8.05(4.91,10.33),差异具有统计学意义(z=-2.461、p=0.014)；₁₈^{F-FAPI PET/CT}与₁₈^{F-FDG PET/CT}显像在9例肝脏原发性病变的SUV_max分别为13.06(7.30,18.22)、5.94(3.01,8.82),差异具有统计学意义(z=-2.429、p=0.015)；₁₈^{F-FAPI PET/CT}与₁₈^{F-FDG PET/CT}显像在9例肝脏转移性病变的SUV_max分别为10.42(7.7,14.17)、10.16(6.53,13.86),差异无统计学意义(z=-0.533、p=0.594)。18例阳性病变(原发性9例、转移性9例)的肿瘤代谢体积参数MTV_4.0分别为29.29(3.41,34.72)、18.02(0.85,31.05),差异有统计学意义(z=-2.243、p=0.025)；TLF_4.0分别为208.73(19.49,262.61)、111.48(3.73,213.38),差异有统计学意义(z=-2.373、p =0.018)；9例肝脏原发性病变TLF_2.5分别为337.06(78.41,462.48)、191.25(10.41,352.41),差异有统计学意义(z=-2.073、p =0.048)；肝脏原发性病变TLF_3.0分别为307.95(55.89,393.50)、160.46(0.05,279.24),差异有统计学意义(z=-2.429、p=0.015)；9例肝脏转移性病变在不同固定阈值及百分比阈值MTV与TLF之间的比较,差异均无统计学意义。两位观察者对肝脏病灶视觉分析一致性为100%,Kappa=1.000,z=4.88、p<0.001。两位观察者对肝脏病灶数量一致性为88.89%,Kappa=82.35,z=5.36、p<0.001;FDG显像分析一致性为88.89%,Kappa=82.35,z=4.16、p<0.001。1h、2ｈ显像的图像对比度,p =0.1289,无明显统计学差异；1h SUV_max和2 h SUV_max之间Pearson相关系数为0.7928,p＜0.05,表明两者具有显著相关性。结论 ₁₈^F-FAPI在肝脏原发性病变中显示出较高的病灶与本底对比度,可以弥补₁₈^{F-FDG PET/CT}在检测原发性肝癌方面的不足。因此,FAPI的肝脏肿瘤中的高选择性摄取可能为肿瘤的无创性诊断、分期以及肿瘤治疗疗效监测开辟新的应用领域。

Abstract:

ABSTRACT: OBJECTIVE To compare and evaluate the diagnostic efficacy of 18F-FAPI PET/CT and 18F-FDG PET/CT in liver malignant tumors, analyze the diagnostic thresholds of SUVmax for the two tracers, and explore their diagnostic value in liver malignant tumors. METHODS Clinical and imaging data of 20 patients (16 males, 4 females; median age 65 years) who underwent 18F-FAPI PET/CT and 18F-FDG PET/CT at the Affiliated Hospital of Jiangnan University from February to July 2023 were retrospectively analyzed. All patients underwent both 18F-FAPI PET/CT and 18F-FDG PET/CT within ≤7 days. Histopathology served as the gold standard for final diagnosis; for cases unsuitable for tissue diagnosis, imaging follow-up was used to determine the presence of liver malignant tumors. The PET/CT imaging findings of the two tracers were compared. The Wilcoxon signed-rank test was applied to compare the differences in SUVmax, MTV, and LBR between 18F-FAPI PET/CT and 18F-FDG PET/CT. The Kappa test evaluated the consistency of lesion identification between two observers. The Wilcoxon paired rank sum test for SUVmax [M(P25,75)] was used to assess the image contrast and correlation between 1h and 2h imaging. A P < 0.05 was considered statistically significant. RESULTS For 18 positive lesions (9 primary, 9 metastatic), the SUVmax of 18F-FAPI PET/CT and 18F-FDG PET/CT were 11.74(7.65,15.51) and 8.05(4.91,10.33), respectively, with a statistically significant difference (z=-2.461, p=0.014). In 9 primary liver lesions, the SUVmax were 13.06(7.30,18.22) and 5.94(3.01,8.82), respectively (z=-2.429, p=0.015); in 9 metastatic liver lesions, the SUVmax were 10.42(7.7,14.17) and 10.16(6.53,13.86), respectively, with no significant difference (z=-0.533, p=0.594). For 18 positive lesions, the MTV4.0 were 29.29(3.41,34.72) and 18.02(0.85,31.05) (z=-2.243, p=0.025), and TLF4.0 were 208.73(19.49,262.61) and 111.48(3.73,213.38) (z=-2.373, p=0.018), showing significant differences. In 9 primary liver lesions, TLF2.5were 337.06(78.41,462.48) and 191.25(10.41,352.41) (z=-2.073, p=0.048), and TLF3.0 were 307.95(55.89,393.50) and 160.46(0.05,279.24) (z=-2.429, p=0.015), with significant differences. No significant differences were found in MTV and TLF of 9 metastatic liver lesions under different fixed thresholds and percentage thresholds. The visual analysis consistency of liver lesions between two observers was 100% (Kappa=1.000, z=4.88, p<0.001). The consistency in lesion number was 88.89% (Kappa=82.35, z=5.36, p<0.001), and the FDG imaging analysis consistency was 88.89% (Kappa=82.35, z=4.16, p<0.001). There was no significant difference in image contrast between 1h and 2h imaging (p=0.1289), while the Pearson correlation coefficient between 1h SUVmax and 2h SUVmax was 0.7928 (p<0.05), indicating a significant correlation. CONCLUSION 18F-FAPI shows higher lesion-to-background contrast in primary liver lesions, which can compensate for the limitations of 18F-FDG PET/CT in detecting primary liver cancer. Therefore, the highly selective uptake of FAPI in liver tumors may open up new application fields for non-invasive tumor diagnosis, staging, and therapeutic efficacy monitoring.