Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
iCAD Inc., Nashua, New Hampshire.
Int J Radiat Oncol Biol Phys. 2014 Jul 1;89(3):658-65. doi: 10.1016/j.ijrobp.2014.03.006.
To generate a population-averaged arterial input function (PA-AIF) for quantitative analysis of dynamic contrast-enhanced MRI data in head and neck cancer patients.
Twenty patients underwent dynamic contrast-enhanced MRI during concurrent chemoradiation therapy. Imaging consisted of 2 baseline scans 1 week apart (B1/B2) and 1 scan after 1 week of chemoradiation therapy (Wk1). Regions of interest (ROIs) in the right and left carotid arteries were drawn on coronal images. Plasma concentration curves of all ROIs were averaged and fit to a biexponential decay function to obtain the final PA-AIF (AvgAll). Right-sided and left-sided ROI plasma concentration curves were averaged separately to obtain side-specific AIFs (AvgRight/AvgLeft). Regions of interest were divided by time point to obtain time-point-specific AIFs (AvgB1/AvgB2/AvgWk1). The vascular transfer constant (Ktrans) and the fractional extravascular, extracellular space volume (Ve) for primaries and nodes were calculated using the AvgAll AIF, the appropriate side-specific AIF, and the appropriate time-point-specific AIF. Median Ktrans and Ve values derived from AvgAll were compared with those obtained from the side-specific and time-point-specific AIFs. The effect of using individual AIFs was also investigated.
The plasma parameters for AvgAll were a1,2 = 27.11/17.65 kg/L, m1,2 = 11.75/0.21 min(-1). The coefficients of repeatability (CRs) for AvgAll versus AvgLeft were 0.04 min(-1) for Ktrans and 0.02 for Ve. For AvgAll versus AvgRight, the CRs were 0.08 min(-1) for Ktrans and 0.02 for Ve. When AvgAll was compared with AvgB1/AvgB2/AvgWk1, the CRs were slightly higher: 0.32/0.19/0.78 min(-1), respectively, for Ktrans; and 0.07/0.08/0.09 for Ve. Use of a PA-AIF was not significantly different from use of individual AIFs.
A PA-AIF for head and neck cancer was generated that accounts for differences in right carotid artery versus left carotid artery, day-to-day fluctuations, and early treatment-induced changes. The small CRs obtained for Ktrans and Ve indicate that side-specific AIFs are not necessary. However, a time-point-specific AIF may improve pharmacokinetic accuracy.
为头颈部癌症患者的动态对比增强 MRI 数据的定量分析生成群体平均动脉输入函数（PA-AIF）。
20 名患者在同期放化疗期间接受了动态对比增强 MRI 检查。成像包括基线扫描（B1/B2），每周 1 次，共 2 次，以及放化疗后 1 周的 1 次扫描（Wk1）。在冠状图像上绘制右和左颈动脉的感兴趣区（ROI）。所有 ROI 的血浆浓度曲线进行平均，并拟合双指数衰减函数，以获得最终的 PA-AIF（AvgAll）。分别对右侧和左侧 ROI 的血浆浓度曲线进行平均，以获得特定于侧的 AIF（AvgRight/AvgLeft）。通过时间点将 ROI 进行划分，以获得特定于时间点的 AIF（AvgB1/AvgB2/AvgWk1）。使用 AvgAll AIF、适当的特定于侧的 AIF 和适当的特定于时间点的 AIF 计算原发性和节点的血管转移常数（Ktrans）和血管外细胞外空间体积分数（Ve）。从 AvgAll 获得的中位数 Ktrans 和 Ve 值与从特定于侧和特定于时间点的 AIF 获得的值进行比较。还研究了使用个体 AIF 的效果。
AvgAll 的血浆参数为 a1,2 = 27.11/17.65 kg/L，m1,2 = 11.75/0.21 min(-1)。AvgAll 与 AvgLeft 的重复性系数（CR）为 Ktrans 的 0.04 min(-1)，Ve 的 0.02。对于 AvgAll 与 AvgRight，Ktrans 的 CR 为 0.08 min(-1)，Ve 的 CR 为 0.02。当将 AvgAll 与 AvgB1/AvgB2/AvgWk1 进行比较时，CR 略高：Ktrans 分别为 0.32/0.19/0.78 min(-1)，Ve 分别为 0.07/0.08/0.09。使用 PA-AIF 与使用个体 AIF 没有显著差异。
生成了一种用于头颈部癌症的 PA-AIF，该 AIF 考虑了右颈动脉与左颈动脉之间的差异、日常波动和早期治疗诱导的变化。Ktrans 和 Ve 获得的小 CR 表明不需要特定于侧的 AIF。然而，特定于时间点的 AIF 可能会提高药代动力学的准确性。
