Li Xin, Huang Wei, Morris Elizabeth A, Tudorica Luminita A, Seshan Venkatraman E, Rooney William D, Tagge Ian, Wang Ya, Xu Jingang, Springer Charles S
W. M. Keck Foundation High-Field MRI Laboratory-Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR 97239, USA.
Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):17937-42. doi: 10.1073/pnas.0804224105. Epub 2008 Nov 13.
The passage of a vascular-injected paramagnetic contrast reagent (CR) bolus through a region-of-interest affects tissue (1)H(2)O relaxation and thus MR image intensity. For longitudinal relaxation [R(1) identical with (T(1))(-1)], the CR must have transient molecular interactions with water. Because the CR and water molecules are never uniformly distributed in the histological-scale tissue compartments, the kinetics of equilibrium water compartmental interchange are competitive. In particular, the condition of the equilibrium trans cytolemmal water exchange NMR system sorties through different domains as the interstitial CR concentration, [CR(o)], waxes and wanes. Before CR, the system is in the fast-exchange-limit (FXL). Very soon after CR(o) arrival, it enters the fast-exchange-regime (FXR). Near maximal [CR(o)], the system could enter even the slow-exchange-regime (SXR). These conditions are defined herein, and a comprehensive description of how they affect quantitative pharmacokinetic analyses is presented. Data are analyzed from a population of 22 patients initially screened suspicious for breast cancer. After participating in our study, the subjects underwent biopsy/pathology procedures and only 7 (32%) were found to have malignancies. The transient departure from FXL to FXR (and apparently not SXR) is significant in only the malignant tumors, presumably because of angiogenic capillary leakiness. Thus, if accepted, this analysis would have prevented the 68% of the biopsies that proved benign.
经血管注射的顺磁性造影剂（CR）团块通过感兴趣区域会影响组织的（1）H（2）O弛豫，进而影响磁共振图像强度。对于纵向弛豫[R（1）等同于（T（1））^（-1）]，CR必须与水发生短暂的分子相互作用。由于CR和水分子在组织学尺度的组织隔室中从未均匀分布，平衡水隔室交换的动力学是竞争性的。特别是，随着间质CR浓度[CR（o）]的增减，平衡跨细胞膜水交换核磁共振系统的状态会通过不同区域变化。在CR之前，系统处于快速交换极限（FXL）。CR（o）到达后很快，它进入快速交换状态（FXR）。在[CR（o）]接近最大值时，系统甚至可能进入缓慢交换状态（SXR）。本文定义了这些状态，并全面描述了它们如何影响定量药代动力学分析。对最初筛查疑似乳腺癌的22名患者的数据进行了分析。参与我们的研究后，这些受试者接受了活检/病理检查，结果仅7人（32%）被发现患有恶性肿瘤。仅在恶性肿瘤中，从FXL到FXR（显然不是SXR）的短暂转变具有显著性，推测是由于血管生成性毛细血管渗漏。因此，如果得到认可，这种分析本可以避免68%被证明为良性的活检。
