Mu Xingyu, Zhang Fangyue, Li Meng, Lu Lu, Mo Biyun, Li Baozhen, Yang Min, Fu Wei
Department of Nuclear Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China.
Department of Rheumatology and Immunology, Affiliated Hospital of Guilin Medical University, Guilin, China.
Eur Radiol. 2025 Apr 27. doi: 10.1007/s00330-025-11610-4.
To evaluate the utility of fibroblast activation protein (FAP) imaging using [¹⁸F]FAPI PET/CT for assessing disease activity and monitoring treatment response in rheumatoid arthritis (RA).
A prospective, single-center study was conducted with 42 RA patients and 8 healthy controls. Participants underwent clinical assessment and [¹⁸F]FAPI PET/CT imaging. Semiquantitative parameters, including standardized uptake value maximum (SUV), lesion-to-muscle ratio (LMR), [¹⁸F]FAPI-avid lesion volume (FLV), and total lesion FAP expression (TLF), were analyzed. Disease activity was stratified by the disease activity score-28 using C-reactive protein (DAS28-CRP) into three groups (low, moderate, and high). Correlations between PET/CT parameters and disease acitivity were examined, and follow-up imaging was performed in ten patients to assess treatment response.
[¹⁸F]FAPI PET/CT identified 201 RA-affected joints with significantly higher SUV in positive joints compared to controls (median 3.6 vs 2.4; p < 0.01). High disease activity was associated with increased SUV (median 5.6 vs 3.3 vs 2.8; p < 0.05), TBR (median 8.4 vs 3.0 vs 3.6; p < 0.05), FLV (162.2 vs 11.5 vs 9.8; p < 0.01), and TLF (569.1 vs 27.3 vs 22.7; p < 0.01). Positive correlations were observed between DAS28-CRP and both FLV (r = 0.50, p < 0.01) and TLF (r = 0.51, p < 0.01). Follow-up imaging revealed significant associations between changes in disease activity and FAP burden.
[¹⁸F]FAPI PET/CT is a promising tool for non-invasive assessment of RA disease activity. It provides quantitative insights into fibroblast activation, offering potential to enhance disease management and therapeutic planning.
Question What is the potential of fibroblast activation imaging using [F]FAPI PET/CT for assessing RA disease activity and monitoring treatment response? Findings F]FAPI PET/CT effectively identifies joint involvement and quantifies fibroblast activation, correlating closely with clinical disease activity in RA. Clinical relevance [F]FAPI PET/CT provides a non-invasive, comprehensive assessment of RA activity, and possible cutoff values for identifying high disease activity.
评估使用[¹⁸F]FAPI PET/CT进行成纤维细胞活化蛋白（FAP）成像在评估类风湿关节炎（RA）疾病活动度及监测治疗反应中的效用。
对42例RA患者和8名健康对照者进行了一项前瞻性单中心研究。参与者接受了临床评估及[¹⁸F]FAPI PET/CT成像。分析了包括标准化摄取值最大值（SUV）、病灶与肌肉比值（LMR）、[¹⁸F]FAPI摄取阳性病灶体积（FLV）和病灶总FAP表达（TLF）在内的半定量参数。采用基于C反应蛋白的28关节疾病活动评分（DAS28-CRP）将疾病活动度分为三组（低、中、高）。研究了PET/CT参数与疾病活动度之间的相关性，并对10例患者进行了随访成像以评估治疗反应。
[¹⁸F]FAPI PET/CT识别出201个受RA影响的关节，阳性关节的SUV显著高于对照组（中位数3.6 vs 2.4；p<0.01）。高疾病活动度与SUV增加（中位数5.6 vs 3.3 vs 2.8；p<0.05）、靶本比（中位数8.4 vs 3.0 vs 3.6；p<0.05）、FLV（162.2 vs 11.5 vs 9.8；p<0.01）和TLF（569.1 vs 27.3 vs 22.7；p<0.01）相关。DAS28-CRP与FLV（r=0.50，p<0.01）和TLF（r=0.51，p<0.01）之间均呈正相关。随访成像显示疾病活动度变化与FAP负荷之间存在显著关联。
[¹⁸F]FAPI PET/CT是一种用于无创评估RA疾病活动度的有前景的工具。它能对成纤维细胞活化进行定量分析，为加强疾病管理和治疗规划提供了潜力。
问题 使用[¹⁸F]FAPI PET/CT进行成纤维细胞活化成像评估RA疾病活动度及监测治疗反应的潜力如何？ 发现 [¹⁸F]FAPI PET/CT能有效识别关节受累情况并量化成纤维细胞活化，与RA临床疾病活动度密切相关。 临床意义 [¹⁸F]FAPI PET/CT为RA活动度提供了一种无创、全面的评估方法及识别高疾病活动度的可能截断值。
