Zhao Min, Zhou Chunqing, Fang Hao, Cao Yan, Hacker Marcus, Li Xiang, Guo Muyao, Yi Xiaoping, Zhang Xiaoli
Department of Nuclear Medicine, The Third Xiangya Hospital, Central South University, Changsha, 410013, China.
Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
Eur J Nucl Med Mol Imaging. 2025 Aug 20. doi: 10.1007/s00259-025-07523-5.
To identify predictors of complete response (CR) following induction therapy in lupus nephritis (LN) and comparatively evaluate the predictive value of baseline [18 F]F-FAPI PET/CT versus [18 F]F-FDG PET/CT for treatment short-term outcomes.
Twenty biopsy-proven LN patients were prospectively enrolled and underwent dual-tracer PET/CT imaging, using both [18 F]F-FAPI and [18 F]F-FDG imaging prior to standardized induction therapy. Treatment response was assessed at 6 months, categorizing into CR, partial response (PR), and non-response (NR) groups. Associations between PET metrics, clinical biomarkers and treatment response were analyzed. Semiquantitative PET parameters including renal standardized uptake values (SUVmax) and target-to-background ratio (TBR) were calculated.
Baseline renal FAPI SUVmax was inversely correlated with estimated glomerular filtration rate (eGFR) and positively with erythrocyte sedimentation rate (ESR) (P < 0.05 for both), whereas FDG SUVmax showed no significant correlation with either parameter. At 6 months, 50% of patients achieved CR, 25% PR, and 25% NR. Patients with CR exhibited significantly lower baseline renal FAPI SUVmax and TBR compared to those with non-CR (PR + NR) (P < 0.01). Visual assessment of FAPI uptake outperformed FDG in predicting CR, with higher accuracy (85% vs. 70%), specificity (90% vs. 50%), and positive predictive value (PPV, 89% vs. 64%), while sensitivity and negative predictive value (NPV) were comparable. Univariate logistic regression identified age > 35 years (P < 0.05) and negative baseline FAPI uptake (P < 0.01) as significant predictors of CR. In multivariate analysis, negative FAPI uptake remained the only independent predictor (P < 0.01).
[18 F]F-FAPI PET/CT demonstrates superior predictive performance over [18 F]F-FDG PET/CT for short-term treatment response in lupus nephritis. It holds promise as a noninvasive imaging biomarker to guide clinical decision-making and optimize individualized therapy.
确定狼疮性肾炎（LN）诱导治疗后完全缓解（CR）的预测因素，并比较评估基线[¹⁸F]F-FAPI PET/CT与[¹⁸F]F-FDG PET/CT对治疗短期结局的预测价值。
前瞻性纳入20例经活检证实的LN患者，在标准化诱导治疗前接受双示踪剂PET/CT成像，同时使用[¹⁸F]F-FAPI和[¹⁸F]F-FDG成像。在6个月时评估治疗反应，分为CR、部分缓解（PR）和无反应（NR）组。分析PET指标、临床生物标志物与治疗反应之间的关联。计算包括肾脏标准化摄取值（SUVmax）和靶本比（TBR）在内的半定量PET参数。
基线肾脏FAPI SUVmax与估计肾小球滤过率（eGFR）呈负相关，与红细胞沉降率（ESR）呈正相关（两者P均<0.05），而FDG SUVmax与这两个参数均无显著相关性。在6个月时，50%的患者达到CR，25%为PR，25%为NR。与非CR（PR+NR）患者相比，CR患者的基线肾脏FAPI SUVmax和TBR显著更低（P<0.01）。在预测CR方面，FAPI摄取的视觉评估优于FDG，具有更高的准确性（85%对70%）、特异性（90%对50%）和阳性预测值（PPV，分别为89%和64%），而敏感性和阴性预测值（NPV）相当。单因素逻辑回归确定年龄>35岁（P<0.05）和基线FAPI摄取阴性（P<0.01）是CR的显著预测因素。在多因素分析中，FAPI摄取阴性仍然是唯一的独立预测因素（P<0.01）。
[¹⁸F]F-FAPI PET/CT在狼疮性肾炎短期治疗反应方面显示出优于[¹⁸F]F-FDG PET/CT的预测性能。它有望作为一种非侵入性成像生物标志物来指导临床决策并优化个体化治疗。
