超顺磁性聚合物胶束的失谐饱和磁共振成像
Off-resonance saturation magnetic resonance imaging of superparamagnetic polymeric micelles.
作者信息
Khemtong Chalermchai, Kessinger Chase W, Togao Osamu, Ren Jimin, Takahashi Masaya, Sherry A Dean, Gao Jinming
机构信息
Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8807, USA.
出版信息
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:4095-7. doi: 10.1109/IEMBS.2009.5334550.
An off-resonance saturation (ORS) method was used for magnetic resonance imaging of superparamagnetic polymeric micelles (SPPM). SPPM was produced by encapsulating a cluster of magnetite nanoparticles (9.9+/-0.4 nm in diameter) in poly(ethylene glycol)-b-poly(D,L-lactide) (PEG-PLA) copolymer micelles (micelle diameter: 60+/-9 nm). In ORS MRI, a selective radiofrequency (RF) pulse was applied at an off-resonance position (0-50 ppm) from the bulk water signal, and the SPPM particles were visualized by the contrast on a division image constructed from two images acquired with and without pre-saturation. Here, the effects of saturation offset frequencies, saturation durations, and RF powers on ORS contrasts were investigated as these parameters are critical for optimization of ORS MRI for in vivo imaging applications. The ability to turn "ON" and "OFF" ORS contrast of SPPM solutions permits for an accurate image subtraction and a contrast enhancement to visualize SPPM probes for in vivo imaging of cancer.
采用非共振饱和（ORS）方法对超顺磁性聚合物胶束（SPPM）进行磁共振成像。通过将一簇磁铁矿纳米颗粒（直径9.9±0.4 nm）包裹在聚（乙二醇）-b-聚（D，L-丙交酯）（PEG-PLA）共聚物胶束（胶束直径：60±9 nm）中来制备SPPM。在ORS MRI中，在距主体水信号0 - 50 ppm的非共振位置施加选择性射频（RF）脉冲，并通过由有和没有预饱和的情况下采集的两幅图像构建的分割图像上的对比度来观察SPPM颗粒。在此，研究了饱和偏移频率、饱和持续时间和RF功率对ORS对比度的影响，因为这些参数对于体内成像应用的ORS MRI优化至关重要。开启和关闭SPPM溶液的ORS对比度的能力允许进行精确的图像减法和对比度增强，以可视化用于癌症体内成像的SPPM探针。
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