Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Int J Radiat Oncol Biol Phys. 2012 Mar 1;82(3):e345-50. doi: 10.1016/j.ijrobp.2011.05.059. Epub 2011 Oct 8.
Dynamic contrast-enhanced (DCE) MRI-extracted parameters measure tumor microvascular physiology and are usually calculated from an intratumor region of interest (ROI). Optimal ROI delineation is not established. The valid clinical use of DCE-MRI requires that the variation for any given parameter measured within a tumor be less than that observed between tumors in different patients. This work evaluates the impact of tumor ROI selection on the assessment of intra- and interpatient variability.
Head and neck cancer patients received initial targeted therapy (TT) treatment with erlotinib and/or bevacizumab, followed by radiotherapy and concurrent cisplatin with synchronous TT. DCE-MRI data from Baseline and the end of the TT regimen (Lead-In) were analyzed to generate the vascular transfer function (K(trans)), the extracellular volume fraction (v(e)), and the initial area under the concentration time curve (iAUC(1 min)). Four ROI sampling strategies were used: whole tumor or lymph node (Whole), the slice containing the most enhancing voxels (SliceMax), three slices centered in SliceMax (Partial), and the 5% most enhancing contiguous voxels within SliceMax (95Max). The average coefficient of variation (aCV) was calculated to establish intrapatient variability among ROI sets and interpatient variability for each ROI type. The average ratio between each intrapatient CV and the interpatient CV was calculated (aRCV).
Baseline primary/nodes aRCVs for different ROIs not including 95Max were, for all three MR parameters, in the range of 0.14-0.24, with Lead-In values between 0.09 and 0.2, meaning a low intrapatient vs. interpatient variation. For 95Max, intrapatient CVs approximated interpatient CVs, meaning similar data dispersion and higher aRCVs (0.6-1.27 for baseline) and 0.54-0.95 for Lead-In.
Distinction between different patient's primary tumors and/or nodes cannot be made using 95Max ROIs. The other three strategies are viable and equivalent for using DCE-MRI to measure head and neck cancer physiology.
动态对比增强（DCE）MRI 提取的参数可测量肿瘤微血管生理学，通常是从肿瘤内感兴趣区（ROI）计算得出。目前尚未确定最佳 ROI 勾画方法。DCE-MRI 的临床有效应用要求，在给定肿瘤内测量的任何参数的变化小于不同患者之间肿瘤之间的变化。本研究评估了肿瘤 ROI 选择对评估患者内和患者间变异性的影响。
头颈部癌症患者接受初始靶向治疗（TT）治疗，包括厄洛替尼和/或贝伐单抗，随后进行放疗和同期顺铂同步 TT。对基线和 TT 方案结束时（导入期）的 DCE-MRI 数据进行分析，以生成血管传递函数（K(trans)）、细胞外容积分数（v(e)）和初始浓度时间曲线下面积（iAUC(1 min)）。使用了四种 ROI 采样策略：整个肿瘤或淋巴结（整体）、包含最多增强体素的切片（SliceMax）、位于 SliceMax 中心的三个切片（部分）和 SliceMax 内的 5%最增强连续体素（95Max）。计算平均变异系数（aCV）以建立不同 ROI 集之间的患者内变异性和每种 ROI 类型的患者间变异性。计算每个患者内 CV 与患者间 CV 之间的平均比值（aRCV）。
不同 ROI （不包括 95Max）的基线原发/淋巴结的所有三个 MR 参数的 aRCV 均在 0.14-0.24 之间，而导入期值在 0.09 和 0.2 之间，这意味着患者内与患者间的变化较小。对于 95Max，患者内 CV 接近患者间 CV，意味着数据分散相似，aRCV 更高（基线为 0.6-1.27），导入期为 0.54-0.95。
不能使用 95Max ROI 区分不同患者的原发肿瘤和/或淋巴结。其他三种策略可用于使用 DCE-MRI 测量头颈部癌症生理学，是可行且等效的。
