Our purpose was to assess the diagnostic potential of simultaneously acquired ¹⁸F-FDG PET and MRI data sets for therapy response assessment of isolated limb perfusion (ILP) in patients with soft-tissue sarcomas (STS). Methods: In total, 45 patients with histopathologically verified STS were prospectively enrolled for an integrated ¹⁸F-FDG PET/MRI examination before and after ILP. Therapy response was assessed based on different MRI- and PET-derived morphologic (RECIST and the MR-adapted Choi criteria) and metabolic (PERCIST) criteria. In addition, a regression model was used combining relative changes in quantitative variables to predict treatment response under ILP. Histopathologic results after subsequent tumor resection served as the reference standard, and patients were categorized as responders or nonresponders on the basis of the 6-stage regression scale by Salzer-Kuntschik. Results: Histopathologic analysis categorized 27 patients as responders (grades I–III) and 18 patients as nonresponders (grades IV–VI). Calculated sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were 22%, 89%, 75%, 43%, and 49% for RECIST; 70%, 44%, 66%, 50%, and 60% for the Choi criteria; and 85%, 78%, 85%, 78%, and 82% for PERCIST. Receiver-operating-characteristic analysis revealed an area under the curve (AUC) of 0.56 for RECIST, 0.57 for the Choi criteria, and 0.82 for PERCIST. The combined regression model revealed higher values (AUC, 0.90) than for the stand-alone analysis, however, differences to metabolic parameters did not reach significance (P value: 0.067). Conclusion: Our study demonstrates the superiority of ¹⁸F-FDG PET over MRI data sets for response assessment of STS under neoadjuvant ILP. In a clinical setting, MRI delivers valuable information for presurgical assessment. Therefore, combining ¹⁸F-FDG PET and MRI data may enable more reliable treatment planning and therapy monitoring of STS.

我们的目的是评估同时获取的^18个F-FDG PET和MRI数据集对软组织肉瘤（STS）患者的孤立肢体灌注（ILP）的治疗反应评估的诊断潜力。方法：前瞻性纳入45例经组织病理学证实为STS的患者，其中^18例综合在ILP之前和之后进行F-FDG PET / MRI检查。根据不同的MRI和PET衍生的形态学（RECIST和MR适应的Choi标准）和代谢（PERCIST）标准评估治疗反应。另外，使用回归模型结合定量变量的相对变化来预测ILP下的治疗反应。随后的肿瘤切除后的组织病理学结果作为参考标准，Salzer-Kuntschik根据6阶段回归量表将患者分为反应者或非反应者。结果：组织病理学分析将27例患者归为有反应者（I–III级），将18例患者归为无反应者（IV–VI级）。RECIST的计算灵敏度，特异性，阳性和阴性预测值以及诊断准确性分别为22％，89％，75％，43％和49％。Choi标准的70％，44％，66％，50％和60％；以及PERCIST的85％，78％，85％，78％和82％。接收者操作特性分析显示，RECIST的曲线下面积（AUC）为0.56，Choi标准的曲线下面积为0.57，PERCIST的曲线下面积为0.82。组合回归模型显示的值（AUC，0.90）比独立分析的值高，但是，代谢参数的差异没有达到显着性（P值：0.067）。结论：我们的研究表明¹⁸的优越性通过F-FDG PET MRI数据集评估新辅助ILP下STS的反应。在临床环境中，MRI可提供有价值的信息以进行术前评估。因此，结合¹⁸ F-FDG PET和MRI数据可以实现更可靠的STS治疗计划和治疗监测。