摘要
目的:通过立体定位仪向裸小鼠脑内直接注入MR对比剂(Gd-DTPA)和/或美蓝试剂,形成假肿瘤灶, 探讨1.5T MR机显示裸小鼠脑内病变的可行性,进行相关MR信号分析,为建立1.5T MR接种胶质瘤的裸小鼠脑研究模型作准备。材料与方法:30只裸小鼠,雌雄各半,体重约20g,随机分成注射Gd-DTPA 1组(1μl)、注射Gd-DTPA 2组(2μl)、注射美蓝试剂1组(1μl)、注射美蓝试剂2组(2μl)、注射Gd-DTPA和美蓝试剂混合液1组(1μl)和注射Gd-DTPA和美蓝试剂混合液2组(2μl),每组各5只。裸小鼠腹腔麻醉后,固定于立体定位仪上,经颅骨缺口,用微注射器往一侧大脑尾状核部注入相应制剂,注完后行MR检查。MR扫描采用Siemens 1.5T超导型MR机,头部线圈,用水模作为裸小鼠支架,将裸小鼠置于线圈中心,分别行T1WI、T2WI横断面、矢状面和冠状面扫描,SE序列。观察各组裸小鼠脑内是否可见明确异常信号及位置,测量异常信号灶的大小及信号强度,分析异常信号成因。结果:除注射美蓝试剂的2组外,其他各组裸小鼠注射侧脑内相应部位见明确可辨的假肿瘤样异常信号改变。各扫描平面假肿瘤灶均呈类圆形,分界清楚,T1WI呈周围环形高信号,中心低信号,T2WI呈低信号。假肿瘤灶与周围及对侧正常脑组织对比鲜明,两者信号强度差别有统计学意义(P>0.05)。结论:①1.5T MR机可明确显示裸小鼠脑内异常信号灶。②美蓝试剂不引起裸小鼠脑信号强度改变。③裸小鼠脑内假肿瘤灶的T1WI特征性信号改变源于对比剂浓度差别。
Abstract
Objective: To evaluate the feasibility of imaging pseudotumor injected into nude mice intracranially at 1.5T MR system and to study the manifestation of MRI. Methods: Thirty nude mice were included in this study and distributed into six study groups: injecting Gd-DTPA(1μl), Gd-DTPA(2μl), Methtlene blue(1μl), Methtlene blue(2μl), mixing of Gd-DTPA and Methtlene blue(1μl), mixing of Gd-DTPA and Methtlene blue(2μl). Animals were anesthetized with thiopental sodium. After injection of corresponding reagent by using steriotatic method, the mice were transferred immediately to the MR imaging unit. Unenhanced SE and FSE images were performed with a 1.5T superconducting magnet. Signal intensity of pseudotumor and normal brain parenchyma was measured with 3 different regions of interest. Relative value(%) of enhancement was measured and compared. Volume of pseudotumor were measured and compared. Results: MR images of quite good quality were obtained in all the 30 mice. No pseudotumor was observed in the Methtlene blue(1μl) group and Methtlene blue(2μl) group. In the other groups, pseudotumor presented as focus of short T1 signals in the edge, long T1 signals in the center and short T2 signals. Relative values between pseudotumor enhancement and normal brain were different statistically in each group and there was no statistical difference in the relative value of pseudotumor across the four groups. The volume of pseudotumor was lowest in the mixing of Gd-DTPA and Methtlene blue(1μl) group than in the other groups. Conclusion: MRI is feasible in imaging nude mice brain and detect abnormal signals focus. Methtlene blue as a potential antitumor reagent had no obvious change of signal intensity of nude mice brain. The characteric signal of pseudotumor arise from the difference of the concentration of Gd-DTPA in local nude mice brain.
关键词
小鼠 /
裸 /
脑肿瘤 /
磁共振成像
Key words
mice /
nude /
brain neoplasms /
magnetic resonance imaging
徐 亮;沈钧康;张红丽;李如军;秦明明;许建铭;黄 强;钱铭辉;郭启勇.
裸小鼠脑内注射性假肿瘤灶的MR分析[J]. 中国临床医学影像杂志. 2006, 17(9): 518-522
XU Liang;SHEN Jun-kang;ZHANG Hong-li;LI Ru-jun;QIN Ming-ming;XU Jian-ming;HUANG Qiang;QIAN Ming-hui;GUO Qi-yong.
MRI analysis of pseudotumor injected into nude mice intracranially[J]. Journal of China Clinic Medical Imaging. 2006, 17(9): 518-522
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