Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada.
Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada.
J Neurooncol. 2021 Jan;151(2):267-278. doi: 10.1007/s11060-020-03661-y. Epub 2020 Nov 16.
Quantitative MRI (qMRI) was performed using a 1.5T protocol that includes a novel chemical exchange saturation transfer/magnetization transfer (CEST/MT) approach. The purpose of this prospective study was to determine if qMRI metrics at baseline, at the 10th and 20th fraction during a 30 fraction/6 week standard chemoradiation (CRT) schedule, and at 1 month following treatment could be an early indicator of response for glioblastoma (GBM).
The study included 51 newly diagnosed GBM patients. Four regions-of-interest (ROI) were analyzed: (i) the radiation defined clinical target volume (CTV), (ii) radiation defined gross tumor volume (GTV), (iii) enhancing-tumor regions, and (iv) FLAIR-hyperintense regions. Quantitative CEST, MT, T and T parameters were compared between those patients progressing within 6.9 months (early), and those progressing after CRT (late), using mixed modelling. Exploratory predictive modelling was performed to identify significant predictors of early progression using a multivariable LASSO model.
Results were dependent on the specific tumor ROI analyzed and the imaging time point. The baseline CEST asymmetry within the CTV was significantly higher in the early progression cohort. Other significant predictors included the T of the MT pools (for semi-solid at fraction 20 and water at 1 month after CRT), the exchange rate (at fraction 20) and the MGMT methylation status.
We observe the potential for multiparametric qMRI, including a novel pulsed CEST/MT approach, to show potential in distinguishing early from late progression GBM cohorts. Ultimately, the goal is to personalize therapeutic decisions and treatment adaptation based on non-invasive imaging-based biomarkers.
使用包括新型化学交换饱和传递/磁化转移（CEST/MT）方法的 1.5T 方案进行定量 MRI（qMRI）。本前瞻性研究的目的是确定在标准放化疗（CRT）方案的 30 个分数/6 周期间的基线、第 10 个和第 20 个分数以及治疗后 1 个月时的 qMRI 指标是否可以作为胶质母细胞瘤（GBM）反应的早期指标。
该研究纳入了 51 例新诊断的 GBM 患者。分析了四个感兴趣区域（ROI）：（i）辐射定义的临床靶区（CTV），（ii）辐射定义的大体肿瘤体积（GTV），（iii）增强肿瘤区域，以及（iv）FLAIR 高信号区域。使用混合模型比较了在 6.9 个月内进展（早期）的患者与 CRT 后进展（晚期）的患者之间的定量 CEST、MT、T 和 T 参数。使用多变量 LASSO 模型进行探索性预测建模，以确定早期进展的显著预测因子。
结果取决于特定的肿瘤 ROI 和成像时间点。早期进展队列的 CTV 内 CEST 不对称性在基线时显著更高。其他显著的预测因子包括 MT 池的 T（在第 20 个分数时为半固体，在 CRT 后 1 个月时为水）、交换率（在第 20 个分数时）和 MGMT 甲基化状态。
我们观察到包括新型脉冲 CEST/MT 方法在内的多参数 qMRI 具有区分早期和晚期进展 GBM 队列的潜力。最终，目标是基于非侵入性成像生物标志物来个性化治疗决策和治疗适应。
