Waters Emily A, Chen Junjie, Yang Xiaoxia, Zhang Huiying, Neumann Robert, Santeford Andrea, Arbeit Jeffrey, Lanza Gregory M, Wickline Samuel A
Department of Medicine, Division of Cardiology, Washington University Medical School, St Louis, Missouri, USA.
Magn Reson Med. 2008 Nov;60(5):1232-6. doi: 10.1002/mrm.21794.
Real-time detection of targeted contrast agent binding is challenging due to background signal from unbound agent. (19)F diffusion weighted MR spectroscopy (DWS) could selectively detect binding of angiogenesis-targeted perfluorocarbon nanoparticles in vivo. Transgenic K14-HPV16 mice with epidermal squamous carcinomas exhibiting up-regulated neovasculature were used, with nontransgenic littermates as controls. Mice were treated with alpha(v)beta(3)-integrin targeted perfluorocarbon nanoparticles. (19)F DWS (b-values from 0 to 16,000 s/mm(2)) was performed on mouse ears in vivo at 11.74 Tesla. Progressive decay of (19)F signal with increased diffusion weighting at low b-values (< 1500 s/mm(2)) was observed in ears of both K14-HPV16 and control mice, demonstrating suppression of background (19)F signal from unbound nanoparticles in the blood. Much of the (19)F signal from ears of K14-HPV16 mice persisted at high b-values, indicating a stationary signal source, reflecting abundant nanoparticle binding to angiogenesis. (19)F signal in controls decayed completely at high b-values (> 1500 s/mm(2)), reflecting a moving signal source due to absence of angiogenesis (no binding sites). Estimated ADCs of nanoparticles in K14-HPV16 and control mice were 33.1 +/- 12.9 microm(2)/s and 19563 +/- 5858 microm(2)/s (p < 0.01). In vivo (19)F DWS can be used for specific detection of bound perfluorocarbon nanoparticles by selectively suppressing background (19)F signal from nanoparticles flowing in blood.
由于未结合造影剂的背景信号,靶向造影剂结合的实时检测具有挑战性。(19)F扩散加权磁共振波谱(DWS)可以在体内选择性地检测血管生成靶向全氟碳纳米颗粒的结合。使用具有表皮鳞状癌且新血管生成上调的转基因K14-HPV16小鼠,以非转基因同窝小鼠作为对照。小鼠用α(v)β(3)整合素靶向全氟碳纳米颗粒治疗。在11.74特斯拉对小鼠耳朵进行体内(19)F DWS(b值从0到16,000 s/mm²)。在低b值(<1500 s/mm²)时,随着扩散加权增加,K14-HPV16小鼠和对照小鼠耳朵中的(19)F信号均出现渐进性衰减,表明血液中未结合纳米颗粒的背景(19)F信号受到抑制。K14-HPV16小鼠耳朵的大部分(19)F信号在高b值时持续存在,表明存在固定信号源,反映了纳米颗粒与血管生成的大量结合。对照中的(19)F信号在高b值(>1500 s/mm²)时完全衰减,反映了由于缺乏血管生成(无结合位点)导致的移动信号源。K14-HPV16小鼠和对照小鼠中纳米颗粒的估计表观扩散系数(ADC)分别为33.1±12.9μm²/s和19563±5858μm²/s(p<0.01)。体内(19)F DWS可通过选择性抑制血液中流动纳米颗粒的背景(19)F信号,用于特异性检测结合的全氟碳纳米颗粒。