Rad Ali M, Arbab Ali S, Iskander A S M, Jiang Quan, Soltanian-Zadeh Hamid
Department of Radiology, Henry Ford Health System, Detroit, Michigan 48202, USA.
J Magn Reson Imaging. 2007 Aug;26(2):366-74. doi: 10.1002/jmri.20978.
To show the feasibility of using magnetic resonance imaging (MRI) to quantify superparamagnetic iron oxide (SPIO)-labeled cells.
Lymphocytes and 9L rat gliosarcoma cells were labeled with ferumoxides-protamine sulfate complex (FE-PRO). The cells were labeled efficiently (more than 95%) and the iron concentration inside each cell was measured by spectrophotometry (4.77-30.21 pg). Phantom tubes containing different numbers of labeled or unlabeled cells, as well as different concentrations of FE-PRO, were made. In addition, labeled and unlabeled cells were injected into fresh and fixed rat brains.
Cellular viability and proliferation of labeled and unlabeled cells were shown to be similar. T2-weighted images were acquired using 7T and 3T MRI systems, and R2 maps of the tubes containing cells, free FE-PRO, and brains were made. There was a strong linear correlation between R2 values and labeled cell numbers, but the regression lines were different for the lymphocytes and gliosarcoma cells. Similarly, there was strong correlation between R2 values and free iron. However, free iron had higher R2 values than the labeled cells for the same concentration of iron.
Our data indicate that in vivo quantification of labeled cells can be done by careful consideration of different factors and specific control groups.
展示使用磁共振成像（MRI）定量超顺磁性氧化铁（SPIO）标记细胞的可行性。
用硫酸铁铵 - 鱼精蛋白复合物（FE - PRO）标记淋巴细胞和9L大鼠胶质肉瘤细胞。细胞被高效标记（超过95%），并且通过分光光度法测量每个细胞内的铁浓度（4.77 - 30.21皮克）。制作了含有不同数量标记或未标记细胞以及不同浓度FE - PRO的模型管。此外，将标记和未标记的细胞注入新鲜和固定的大鼠脑中。
标记和未标记细胞的细胞活力和增殖情况相似。使用7T和3T MRI系统采集T2加权图像，并制作了含有细胞、游离FE - PRO和脑的模型管的R2图。R2值与标记细胞数量之间存在强线性相关性，但淋巴细胞和胶质肉瘤细胞的回归线不同。同样，R2值与游离铁之间也存在强相关性。然而，对于相同浓度的铁，游离铁的R2值高于标记细胞。
我们的数据表明，通过仔细考虑不同因素和特定对照组，可以在体内对标记细胞进行定量。
