三维薄层磁共振涎管造影方法探讨及不同重复时间的对比研究

Methods of 3D heavily T_2-weighted fast spin-echo MR sialography and comparative study of repetition time

目的:通过线圈和序列的选择、不同重复时间(TR)的对比研究以及其他扫描参数的优化,探讨三维薄层磁共振涎管造影的成像方法。材料与方法:10名无涎腺病变志愿者,采用SENSE-FLEX-M线圈和重T2加权快速自旋回波序列,固定回波时间(TE)及其他扫描参数,依次应用不同的TR进行扫描,对涎管的三维造影影像进行评分,计算涎管和背景组织间的对比噪声比,比较不同TR下涎管的评价得分和对比噪声比之间有无差异及统计学意义。结果:不同TR组的磁共振涎管造影影像的得分和对比噪声比之间具有显著性差异。在腮腺管的显示上,2000ms组的得分和对比噪声比低于其他各组(P<0.05);4000ms组高于2000ms组,低于其他组(P<0.05);5000～9000ms组之间无显著性差异(P>0.05)。在颌下腺管的显示上,2000ms组的得分显著低于其他各组(P<0.01),4000～9000ms组之间无显著性差异(P>0.05);2000ms组的CNR显著低于其他各组(P<0.01),4000ms组高于2000ms组,低于其他组(P<0.05),5000～9000ms组之间无显著性差异(P>0.05)。结论:在Philips1.5T磁共振机上行三维重T2加权快速自旋回波磁共振涎管造影,应用SENSE-FLEX-M线圈与特长TR(≥5000ms)能更好地显示涎腺总导管及其分支。

Objective： To optimize the imaging technology of 3D MR sialography on a Philips 1.5T unit by the choice of radiofrequency coil and sequence, and by the comparative study of TR. Methods： Ten volunteers without salivary gland diseases were included in this study. SENSE-FLEX-M coil was used. Serial heavily T2-weighted fast spin-echo sequences of different TR were used in each of the volunteers. The quality of MR sialograms was assessed subjectively by developing a visibility scoring system. Signal intensity of salivary ducts and background tissue were measured in 6 different regions of interest. Contrast to noise ratio（CNR） was measured and compared. Results： The salivary gland ducts and its peripheral branches can be displayed well on images of MR sialography in all volunteers. The score and CNR of parotid gland duct using 2000ms TR were statistically lower than those using other TRs （P〈0.05）. The score and CNR of parotid gland duct using 4000ms TR were higher than those using 2000ms TR, and lower than those using other TRs （P〈0.05）. There was no significant difference between TRs of 5000ms, 6000ms, 7000ms, 8000ms, and 9000ms （P〉0.05）. The score and CNR of submandibular gland duct using 2000ms TR was statistically lower than those using other TRs（P〈0.01）. The CNR using TR 4000ms was higher than that of 2000ms, and lower than those using other TRs （P〈0.05）. There was no significant difference of score between TRs of 4000ms, 5000ms, 6000ms, 7000ms, 8000ms, and 9000ms（P〉0.05）. There was no significant difference of CNR between TRs of 5000ms, 6000ms, 7000ms, 8000ms, and 9000ms （P〉0.05）. Conclusion： It is the best choice for 3D heavily T2-weighted fast spin-echo MR sialography on a Philips 1.5T unit rising SENSE-FLEX-M coil and very long TR at the same time.