7.0T磁共振对磁标记单细胞的成像研究  

Imaging of magnetically labeled single-cell by 7.0 T MR

作　　者：贾振宇[1] 张洪英[1] 陈骏[1] 滕皋军[1] 

机构地区：[1]东南大学附属中大医院放射科,南京210009

出　　处：《中华医学杂志》2010年第21期1467-1471,共5页National Medical Journal of China

摘　　要：目的 7.0T MR系统对氧化铁纳米粒子标记单细胞进行体外成像,并对成像参数进行探讨.方法 3D-FLASH序列对磁标记单细胞计数,对比梯度回波序列与自旋回波序列成像差异,对比梯度回波序列不同回波时间、不同分辨率成像差异.结果 7.0T MR能对磁标记单细胞进行成像,MR图像对细胞浓度为2×103/ml的琼脂糖模型进行细胞计数为1.7×103/ml,与实际浓度一致.2D-FLASH较SE序列对磁标记单细胞导致的T2＊WI信号改变明显,差异有统计学意义;3D-FLASH序列随TE时间延长T2＊效应增强,但图像伪影逐渐明显;分辨率降低单细胞导致的信号缺失明显降低,在200 μm时单细胞导致的信号波动已基本接近琼脂糖背景的内源性波动.结论 7.0T MR系统可对氧化铁纳米粒子标记的单细胞进行探测,选择适合的序列、优化序列内参数可有效提高磁标记细胞的探测敏感性.Objective To detect magnetically labeled single cells in vitro by using 7.0T MRI system and to optimize the parameters used for labeled cell imaging. Methods The endothelial cells ECV-304 were incubated with self-synthesized Fe2O3-PLL Prussian blue stain was employed for identifying intracellular irons. Agarose phantoms of dispersed labeled cells were made with an cell concentration of 2 × 10/ml. 3D-FLASH sequence was employed for the detection of single cells and the cell concentration calculated by counting the number of dark points in MR images; The investigators compared the effects of gradient echo sequence （2D-FLASH） and spin echo sequence （MSME） upon the imaging of magnetically labeled single cells; Also the effects of different echo times （Es） and resolutions of magnetic nanoparticle relaxation upon the imaging of cells were analyzed. Results The endothelial cells ECV-304 were labeled successfully and the labeling efficiency reached almost 100%. Prussian blue staining of Fe2O3-PLL labeled cells revealed the cytoplasmic presence of iron. Single cells were detected as isolated dark points and the cell concentration corresponded with the actual data. The 2D-FLASH sequence had a much stronger T2 ＊ effect than MSME sequence in single cell detection. The T2 ＊ effect increased with the prolongation of TE. The signal loss fell significantly as the resolution decreased. And it reached almost zero when the voxel size reached 200 μm3. Conclusions 7.0T MR system is able to detect magnetically labeled single cells. The optimization of imaging sequences enhances the sensitivity of magnetically labeled single cells. Thus it provides a better method for ire vivo detection of single cells.

关 键 词：磁共振成像 超顺磁性氧化铁 细胞标记 

分 类 号：R445.2[医药卫生—影像医学与核医学]