Quantification of SPIO Nanoparticles in vivo Using the Finite Perturber Method
Quantification of SPIO Nanoparticles in vivo Using the Finite Perturber Method
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DOI：
10.1002/mrm.22727
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发表时间：
2011-05-01
影响因子：
3.3
通讯作者：
Zhao, Qun
中科院分区：
文献类型：
--
作者：
Langley, Jason;Liu, Wei;Zhao, Qun
超顺磁性氧化铁（SPIO）纳米粒子产生的磁化率梯度使其成为磁共振成像中理想的造影剂。基于SPIO纳米颗粒的造影剂的传统量化方法依赖于在区域内映射T-2* 值或通过对造影剂产生的磁场不均匀性进行建模。在这项研究中，一个新的基于模型的SPIO量化方法。所提出的方法模拟磁场的不均匀性，通过近似包含SPIO的磁偶极子的合奏，称为有限微扰法的区域。所提出的方法进行了验证，使用从体模和在体小鼠模型获得的数据。体模由具有四个包埋小瓶的琼脂溶液组成，每个小瓶含有已知但不同浓度的SPIO纳米颗粒。高斯噪声也被添加到体模数据，以测试所提出的方法的性能。使用5只小鼠获得体内数据集，每只小鼠的侧腹皮下植入1 × 10（5）标记和1 × 10（6）未标记的C6胶质瘤细胞。对于体模数据集，所提出的算法可以生成SPIO浓度的准确估计。对于体内数据集，该方法能够给出合理接近已知浓度的SPIO标记肿瘤内浓度的估计。Magn Reson Med 65：1461-1469，2011. (C)2010 Wiley-Liss，Inc.
The susceptibility gradients generated by super-paramagnetic iron oxide (SPIO) nanoparticles make them an ideal contrast agent in magnetic resonance imaging. Traditional quantification methods for SPIO nanoparticle-based contrast agents rely on either mapping T-2* values within a region or by modeling the magnetic field inhomogeneities generated by the contrast agent. In this study, a new model-based SPIO quantification method is introduced. The proposed method models magnetic field inhomogeneities by approximating regions containing SPIOs as ensembles of magnetic dipoles, referred to as the finite perturber method. The proposed method was verified using data acquired from a phantom and in vivo mouse models. The phantom consisted of an agar solution with four embedded vials, each vial containing known but different concentrations of SPIO nanoparticles. Gaussian noise was also added to the phantom data to test performance of the proposed method. The in vivo dataset was acquired using five mice, each of which was subcutaneously implanted in the flanks with 1 x 10(5) labeled and 1 x 10(6) unlabeled C6 glioma cells. For the phantom data set, the proposed algorithm was generate accurate estimations of the concentration of SPIOs. For the in vivo dataset, the method was able to give estimations of the concentration within SPIO-labeled tumors that are reasonably close to the known concentration. Magn Reson Med 65:1461-1469, 2011. (C) 2010 Wiley-Liss, Inc.