Background: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a functional imaging modality that can quantify tissue permeability and blood flow. Due to vasculature changes resulting from radiation therapy (RT), DCE-MRI quantitative parameters should be significantly different in regions receiving a high radiation dose compared to regions receiving a low radiation dose. This study sought to determine whether a significant difference exists in post-head-and-neck-cancer (HNC)-RT DCE-MRI quantitative parameters (Ktransand ve) between regions of the mandible receiving a high radiation dose and regions of the mandible receiving a low radiation dose. Methods: DCE-MRI was acquired from HNC subjects post-RT. The DCE-MRI quantitative parameters Ktransand vewere obtained through Tofts model fitting. Four mandible sections (left ramus, left body, right ramus, and right body) were delineated on subject mandible contours. Two Friedman tests comparing the mean Ktransand vein low-dose (≤60 Gy) areas of the four mandible regions were computed. If the Friedman test determined that a significant difference for a parameter between mandible regions exists, post hoc Wilcoxon signed-rank tests were completed comparing the four mandible regions. If the Friedman test determined that there was no significant difference between mandible regions, a Wilcoxon signed-rank test was used to determine whether a significant difference exists in the parameter between high-dose (>60 Gy) and low-dose (≤60 Gy) mandible regions. Results: 48 HNC subjects were included in the analysis. The Friedman tests showed no significant difference in vemeans between mandible regions (χ(3)2= 1.63,p= 0.44) and a significant difference in Ktransmeans between mandible regions (χ(3)2= 10.29,p= 0.005). Post hoc testing between Ktransmandible regions found that the left body and right body differed significantly from the left ramus and right ramus. The Wilcoxon signed-rank test comparing the mean vebetween high- and low-dose mandible regions found a significant difference (W= 214,p= 0.00013). Conclusions: no inherent difference in the DCE-MRI quantitative parameter vewas observed within subject mandibles, but a significant difference was observed between vemeans in high- and low-radiation-dose mandible regions. These results provide evidence of the utility of DCE-MRI to monitor mandible vasculature changes resulting from head and neck cancer radiation therapy. Monitoring post-HNC-RT mandible vasculature changes is important to initiate earlier toxicity management and ultimately improve HNC survivors’ quality of life.
背景：动态对比增强磁共振成像（DCE-MRI）是一种功能成像技术，能够量化组织通透性和血流量。由于放射治疗（RT）引起的血管系统改变，接受高辐射剂量区域与接受低辐射剂量区域的DCE-MRI定量参数应存在显著差异。本研究旨在确定头颈癌（HNC）放疗后，下颌骨高辐射剂量区域与低辐射剂量区域之间的DCE-MRI定量参数（Ktrans和ve）是否存在显著差异。 方法：采集HNC患者放疗后的DCE-MRI数据，并通过Tofts模型拟合获取定量参数Ktrans和ve。在患者下颌骨轮廓上划分四个区域（左侧升支、左侧体部、右侧升支和右侧体部）。采用两次弗里德曼检验比较四个下颌骨区域低剂量（≤60 Gy）区域的平均Ktrans和ve值。若弗里德曼检验显示某参数在下颌骨区域间存在显著差异，则进一步进行事后威尔科克森符号秩检验比较四个区域；若未发现显著差异，则使用威尔科克森符号秩检验比较高剂量（>60 Gy）与低剂量（≤60 Gy）下颌骨区域间的参数差异。 结果：共纳入48例HNC患者进行分析。弗里德曼检验显示下颌骨区域间ve平均值无显著差异（χ(3)²=1.63，p=0.44），而Ktrans平均值存在显著差异（χ(3)²=10.29，p=0.005）。对Ktrans的事后检验发现，左侧体部与右侧体部均与左侧升支、右侧升支存在显著差异。比较高剂量与低剂量下颌骨区域ve平均值的威尔科克森符号秩检验显示显著差异（W=214，p=0.00013）。 结论：患者下颌骨内DCE-MRI定量参数ve未观察到固有差异，但高、低辐射剂量下颌骨区域间的ve平均值存在显著差异。这些结果证实了DCE-MRI在监测头颈癌放疗所致下颌骨血管系统变化中的实用价值。监测HNC放疗后下颌骨血管变化对早期开展毒性管理、最终改善HNC幸存者生活质量具有重要意义。
Post-RT Head and Neck DCE-MRI: Association Between Mandibular Dose and ve
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