国产室间隔缺损封堵器磁共振检查的实验研究

Magnetic resonance imaging of the homemade ventricular septal defect occluder: an experimental study

目的探讨人体植入国产室间隔缺损封堵器后接受磁共振检查的安全性,以及植入的金属材料对磁共振成像(MRI)的影响程度。方法采用西门子MagnetomImpact-1·0T磁共振机,选用SE和梯度回波(GE)扫描序列,将镍钛合金丝制成的封堵器分别进行MRI磁场内悬挂试验、水模测试扫描、植入中华小型猪体内后心脏扫描等试验;并且对MR检查前后封堵器的磁导率(μ1·5T)以及原子组成等金属特性进行材料学分析测试,观察其有无变化。结果悬挂的封堵器在不同的磁场方向下无明显移位发生。水模测试扫描显示SE序列封堵器水模图像清晰,信号均匀一致,无伪迹干扰,GE序列图像示轻度伪迹干扰,信号尚均匀。植入封堵器后猪心的短轴及长轴面MR成像显示心脏结构观察清楚,SE序列室间隔部位可见轻度金属伪影,GE序列该金属伪影有所放大。MR检查前后封堵器的磁导率(μ1·5T)以及原子组成等金属特性无明显变化。结论这种国产室间隔缺损封堵器属非铁磁性材料,植入人体后行MR检查是安全的,但其产生的金属伪影可部分影响MR图像的观察,通过选择合适的扫描序列和参数可以减轻封堵器伪影的影响。

Objective To evaluate the safety on magnetic resonance (MR) examination of the homemade ventricular septal defect occluder with metal materials, as well as the influential degree on MR imaging. Methods Hanging up the occluder within MRI, testing the occluder with water-template, and scanning the pig′s heart with occluder implantation were performed on 1.0 T MR using the spin echo(SE) and the gradient echo(GE)sequences. The metallic characteristic of the occluder before and after the MR examination was detected by professional apparatus. Results The hanged occluder had no displacement on MR, the occluder had little influence on MR imaging with water-template test and in vivo scan, and the characteristic of the occluder had no obvious change after the MR examination. Conclusion MR examination of patients with the metallic occluder implatation is safe. Artifact cause by the occluder can influence the image observation, however it can be reduced by choosing proper scan sequence and parameters.