摘要
目的优化高场强MRI相控阵线圈的食管高分辨成像参数。方法应用相控阵线圈,对健康志愿者进行食管成像。扫描T2WI,改变呼吸门控、心电门控、视野(FOV)、矩阵、层厚、激励次数(NEX),对不同成像参数下的图像质量、解剖结构显示情况进行评分。结果当应用心电门控,主要参数FOV=18cm、矩阵=288×288、层厚=3mm、NEX=4时可获得良好的图像质量,很好地显示重要的解剖结构,并且扫描时间合理可接受。结论通过本实验优化的参数,MRI食管高分辨成像可为食管癌的影像诊断提供帮助。
Objective To optimize imaging parameters of high-resolution esophagus imaging with phase array coil on 1.5 T. Methods Fifteen healthy volunteers participated in this study. Axial T2 weighted images of esophagus were obtained in all the subjects. At first, the images with different gating conditions, including no gating, respiratory gating and cardiac gating, were evaluated and the best gating condition was picked. With this gating condition, the major parameters, including field of view （FOV）, matrix, slice thickness and number of excitations （NEX）, were adjusted. Each time one parameter was adjusted while the others were kept constant. The whole series of sequences for one parameter adjustment was performed in the same subject and repeated in at least four subjects. The image quality and delineation of the important anatomical structures were visually scored according to the following two criteria. The criteria for image quality included three aspects, which were motion artifact, signal-to-noise ratio and contrast. The criteria for structural delineation included five aspects, which were contrast between mucosa and submucosa versus muscular layer of esophagus, azygos vein, and demarcation between esophagus and posterior border of heart, aorta and vertebra. The scoring was performed by two experienced radiologists respectively. If the values for the same sequence of images scored by the two radiologists differed, consensus was achieved after discussion. The mean of the scores was used for evaluation. Results Cardiac gating was bet- ter than no gating and respiratory gating in better image quality, better delineation of the structures and better demarcation between esophagus and adjacent important structures. The optimal values for FOV, matrix and slice thickness were 1818 cm, 288 X 288 and 3 mm for better image quality and delineation. With NEX equal to 4, the image quality and delineation of the anatomical structures were satisfying while the acquisition time was feasible. Conclusion Good image quality and satisfying delineation of the anatomical structures can be achieved using these optimized parameters with phase array coil on 1.5 T, which can give further information for preoperational imaging diagnosis of esophagus cancer.
出处
《医学影像学杂志》
2013年第3期420-423,430,共5页
Journal of Medical Imaging
关键词
磁共振成像
食管
高分辨
Magnetic resonance imaging
Esophagus
High-resolution
