基于氨基转移机制的乳腺癌磁共振成像初步研究  

Preliminary study of breast cancer in magnetic resonance imaging based on amide proton transfer

作　　者：伍康伟 吴仁华[1] 张苗苗[1] 

机构地区：[1]广东省汕头大学医学院第二附属医院放射科,汕头515041

出　　处：《功能与分子医学影像学（电子版）》2013年第1期35-39,共5页Functional and Molecular Medical Imaging(Electronic Edition)

摘　　要：目的探讨氨基质子转移(APT)成像技术用于乳腺癌诊断的可行性及其意义。方法通过培养MDA-MB-231细胞,选择注射乳腺癌细胞移植方法,在15只约5周BALB/C裸鼠接近后腿的乳腺处,制造乳腺癌裸鼠模型。然后将其置于7 T磁共振动物扫描仪上,采用表面线圈,进行常规T1WI,T2WI序列及CEST序列扫描。CEST运用的是MT偏离水质子峰3.5 ppm的激发偏置脉冲进行扫描,并使用MATLAB软件进行相应处理,获得乳腺癌组织APT图像,最后将获得的乳腺癌组织APT图像与常规T1WI,T2WI序列的图像进行比较。并把相应的肿瘤送病理检查。结果 (1)CSET序列扫描出来的乳腺癌组织Z谱中约于3.5ppm处可见存在CEST效应;(2)乳腺癌组织APT图像可以显示近似常规MR扫描的解剖结构,在其APT的伪彩图像内部可呈现不同的颜色梯度差,检查其不同色阶处感兴趣区,其信号强度显示出差异性;(3)在部分可见肿瘤与周边组织的APT伪彩图中,肿瘤与正常组织存在明显色阶差异,边界区分清楚,而且发现其中一些图像在紧贴肿瘤部分的周边组织色阶与肿瘤相近;(4)乳腺癌的裸鼠模型成功率为100﹪,送检的组织病理结果符合人乳腺癌细胞特征。结论氨基质子转移(APT)成像技术,不仅可以获得近似常规MR序列扫描的空间分辨率,还可以提供癌细胞在肿瘤组织内的分布信息,一定程度上可以间接反映乳腺癌细胞的代谢信息,可能了解肿瘤对周边正常组织的侵袭情况,这些都明显优于常规MR序列扫描,与肿瘤细胞外pH值成像方法对比,具有无创性、安全性及不破坏组织内自然环境等特点,可为乳腺癌诊断提供新的安全可靠的方法。Objective Amide proton transfer （APT） measures the water signal after chemical exchange between free proteins and peptides on the main chain amide matrix in the cells and free water to obtain APT image information. The study was aimed to evaluate APT in breast cancer tissue with a 7T MRI by using APT technique and compare it with conventional MRI and explore the internal environment of breast cancer tissues. Methods Breast cancer was established by inoculating cancer cell line MDA-MB-231 in the mammary gland of fifteen 5-week-old BALB/C nude mice Mice were scanned with surface coil on 7T MRI scanner through conventional sequences of T^WI, T2WI and the sequences of CEST designed by us. CEST-imaging readout was as MT sequence with an offset frequency of 3.5 ppm. We used MATLAB software to analyse the images. APT map of the breast cancer tissue was compared with the T^WI-imaging and T2WI-imaging. Pathological study was performed. Results （1） From the Z-Spectrum which was scanned out by the sequences of CEST on breast cancer tissue, the CEST- effect can be seen at 3.5 PPM. （2） The APT map of breast cancer tissue can reveal the similar anatomic structureto the conventional sequences of MRI. Within its pseudo color images of APT can present the color difference, and the signal strength was different with region of interest in different color gradation. （3） In some pseudo color images of APT which can reveal tumor and the surrounding tissue, well-defined color difference between tumor and normal tissue can be identified. Normal tissue around tumor has a similar color gradation. Conclusion APT is feasible for breast cancer. APT can provide spatial resolution similar to conventional MRI sequences, reveal distribution and metabolic status of cancer cells. APT also provides information about surrounding normal tissue and is superior to conventional MR sequences. Compared to the imaging method that requires tumor cell PH （with contrast agent）, APT is safe and does not destroy normal tissue.

关 键 词：乳腺肿瘤 磁共振成像 

分 类 号：R737.9[医药卫生—肿瘤] R445.2[医药卫生—临床医学]