W.M. Keck Foundation High-Field MRI Laboratory-Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR 97239, United States.
J Magn Reson. 2010 Oct;206(2):190-9. doi: 10.1016/j.jmr.2010.07.004. Epub 2010 Jul 31.
The accurate mapping of the tumor blood volume (TBV) fraction (vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume (vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered.
肿瘤血容量（TBV）分数（vb）的精确映射是一个非常理想的成像生物计量学目标。通常认为，当小分子对比试剂（CR）用于 T1 加权（动态对比增强）DCE-MRI 技术时，实现这一目标是困难的，如果不是不可能的话。这是因为血管生成的恶性肿瘤血管允许 CR 轻易外渗。在这里，应用三部位平衡水交换模型对植入大鼠脑 U87 神经胶质瘤的大脑 DCE-MRI 数据进行分析，该肿瘤表现出快速 CR 外渗。用允许有限水交换动力学的这种“快门”药代动力学模型对（和整个）DCE 数据时间过程的片段进行分析，允许从第一通过段估计 TBV。通过 2D 参数误差曲面的网格搜索测试了参数的成对确定度。呈现了肿瘤血容量（vb）、ve（细胞外、血管外空间体积分数）和 Ktrans（CR 外渗率测量）参数图。还考虑了 DCE-MRI 中 Patlak 图的作用。
