Dubec Michael J, Berks Michael, Price James, McDaid Lisa, Gaffney John, Little Ross A, Cheung Susan, van Herk Marcel, Choudhury Ananya, Matthews Julian C, McPartlin Andrew, Parker Geoff J M, Buckley David L, O'Connor James P B
Division of Cancer Sciences, University of Manchester, Manchester, UK.
Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK.
Phys Imaging Radiat Oncol. 2024 Dec 15;33:100689. doi: 10.1016/j.phro.2024.100689. eCollection 2025 Jan.
Magnetic resonance imaging - linear accelerator (MRI-linac) systems permit imaging of tumours to guide treatment. Dynamic contrast enhanced (DCE)-MRI allows investigation of tumour perfusion. We assessed the feasibility of performing DCE-MRI on a 1.5 T MRI-linac in patients with head and neck cancer (HNC) and measured biomarker repeatability and sensitivity to radiotherapy effects.
Patients were imaged on a 1.5 T MRI-linac or a 1.5 T diagnostic MR system twice before treatment. DCE-MRI parameters including K were calculated, with the optimum pharmacokinetic model identified using corrected Akaike information criterion. Repeatability was assessed by within-subject coefficient of variation (wCV). Treatment effects were assessed as change measured at week 2 of radiotherapy.
14 patients were recruited (6 scanned on diagnostic MR and 8 on MRI-linac), with a total of 24 lesions. Baseline K estimates were comparable on both MR systems; 0.13 [95 %CI: 0.10 to 0.16] min (diagnostic MR) and 0.15 [0.12 to 0.18] min (MRI-linac). wCV values were 22.6 % [95 % CI: 16.2 to 37.3 %] (diagnostic MR) and 11.7 % [8.4 to 19.3 %] (MRI-linac). Combined cohort increase in K was significant (p < 0.01). Similar results were seen for other DCE-MRI parameters.
DCE-MRI is feasible on a 1.5 T MRI-linac system in patients with HNC. Parameter estimates, repeatability, and sensitivity to treatment were similar to those measured on a conventional diagnostic MR system. These data support performing DCE-MRI in studies on the MRI-linac to assess treatment response and adaptive guidance based on tumour perfusion.
磁共振成像 - 直线加速器（MRI - linac）系统可对肿瘤进行成像以指导治疗。动态对比增强（DCE）-MRI能够研究肿瘤灌注情况。我们评估了在1.5T MRI - linac上对头颈癌（HNC）患者进行DCE - MRI检查的可行性，并测量了生物标志物的重复性以及对放疗效果的敏感性。
患者在治疗前在1.5T MRI - linac或1.5T诊断性MR系统上进行了两次成像。计算包括K在内的DCE - MRI参数，并使用校正后的赤池信息准则确定最佳药代动力学模型。通过受试者内变异系数（wCV）评估重复性。在放疗第2周时测量变化来评估治疗效果。
招募了14名患者（6名在诊断性MR上扫描，8名在MRI - linac上扫描），共有24个病灶。两个MR系统上的基线K估计值相当；诊断性MR为0.13 [95%CI：0.10至0.16] min，MRI - linac为0.15 [0.12至0.18] min。wCV值在诊断性MR上为22.6% [95%CI：16.2至37.3%]，在MRI - linac上为11.7% [8.4至19.3%]。联合队列中K的增加具有显著性（p < 0.01）。其他DCE - MRI参数也观察到类似结果。
DCE - MRI在1.5T MRI - linac系统上对HNC患者是可行的。参数估计、重复性以及对治疗的敏感性与在传统诊断性MR系统上测量的结果相似。这些数据支持在MRI - linac研究中进行DCE - MRI以评估治疗反应并基于肿瘤灌注进行适应性引导。
