Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Republic of Korea.
J Nucl Med. 2013 Jul;54(7):1053-9. doi: 10.2967/jnumed.112.115964. Epub 2013 May 13.
We evaluated the potential of (18)F-FDG PET/CT and diffusion-weighted imaging (DWI) to monitor the histologic response in patients with extremity osteosarcoma receiving neoadjuvant chemotherapy, using sequential PET/CT and MR imaging.
We prospectively registered 28 patients with high-grade osteosarcoma treated with 2 cycles of neoadjuvant chemotherapy and surgery. All patients underwent sequential (18)F-FDG PET/CT and MR imaging before (PET/MR1) and after neoadjuvant chemotherapy (PET/MR2). Maximum standardized uptake value (SUV), tumor volume based on MR imaging (MRV), and the mean apparent diffusion coefficient (ADC) values were measured on PET/MR1 (SUV1, MRV1, and ADC1) and PET/MR2 (SUV2, MRV2, and ADC2). The percentage changes in maximum SUV (ΔSUV), MRV (ΔMRV), and ADC (ΔADC) were calculated, and the correlations among these parameters were evaluated. After surgery, the effects of neoadjuvant chemotherapy were graded histopathologically: grades III and IV (necrosis of ≥ 90%) indicated a good response, and grades I and II (necrosis of < 90%) indicated a poor response. The optimum cutoff values of ΔSUV, ΔMRV, ΔADC, and their combination for predicting histologic response were assessed by single- and multi-receiver-operating-characteristic curve analysis.
Twenty-seven patients were enrolled in the present study after 1 patient with inadequate acquisition of MR imaging was excluded. ΔSUV and ΔADC negatively correlated with each other (ρ = -0.593, P = 0.001), and ΔMRV did not correlate with ΔSUV or ΔADC. The cutoff value, sensitivity, specificity, and accuracy for predicting good histologic response were ≤ -52%, 67%, 87%, and 78%, respectively, for ΔSUV and > 13%, 83%, 73%, and 78%, respectively, for ΔADC. However, ΔMRV did not predict histologic response. Sensitivity, specificity, and accuracy were 83%, 87%, and 85%, respectively, using the combined criterion of ΔSUV ≤ -31% and ΔADC > 13%.
In the current preliminary study, both PET/CT and DWI are useful for predicting histologic response after neoadjuvant chemotherapy in osteosarcoma. Combining PET/CT and DWI may be an effective method to predict the histologic response of patients to neoadjuvant chemotherapy.
我们使用（18）F-FDG PET/CT 和弥散加权成像（DWI）评估了在接受新辅助化疗的四肢骨肉瘤患者中监测组织学反应的潜力，使用了连续的 PET/CT 和磁共振成像。
我们前瞻性地登记了 28 名接受 2 个周期新辅助化疗和手术治疗的高级别骨肉瘤患者。所有患者在新辅助化疗前（PET/MR1）和后（PET/MR2）均接受了连续（18）F-FDG PET/CT 和磁共振成像。在 PET/MR1（SUV1、MRV1 和 ADC1）和 PET/MR2（SUV2、MRV2 和 ADC2）上测量最大标准化摄取值（SUV）、基于磁共振成像的肿瘤体积（MRV）和平均表观扩散系数（ADC）值。计算最大 SUV 的变化百分比（ΔSUV）、MRV（ΔMRV）和 ADC（ΔADC），并评估这些参数之间的相关性。手术后，根据组织病理学对新辅助化疗的效果进行分级：III 级和 IV 级（≥90%的坏死）表示良好反应，I 级和 II 级（<90%的坏死）表示不良反应。通过单因素和多因素受试者工作特征曲线分析评估 ΔSUV、ΔMRV、ΔADC 及其组合预测组织学反应的最佳截断值。
在 1 名患者因磁共振成像采集不足而被排除后，本研究共纳入了 27 名患者。ΔSUV 和 ΔADC 之间呈负相关（ρ=-0.593，P=0.001），而 ΔMRV 与 ΔSUV 或 ΔADC 不相关。预测良好组织学反应的截断值、敏感性、特异性和准确性分别为 ΔSUV≤-52%、67%、87%和 78%，ΔADC 分别为>13%、83%、73%和 78%。然而，ΔMRV 并不能预测组织学反应。使用 ΔSUV≤-31%和 ΔADC>13%的联合标准，敏感性、特异性和准确性分别为 83%、87%和 85%。
在目前的初步研究中，PET/CT 和 DWI 均有助于预测骨肉瘤新辅助化疗后的组织学反应。结合 PET/CT 和 DWI 可能是预测骨肉瘤患者新辅助化疗组织学反应的有效方法。
