螺旋桨技术对核磁共振成像中金属固定假牙伪影的改善作用研究

Improvement Effect of PROPELLER Technology on Magnetic Resonance Imaging Artifacts Caused by Fixed Metal Dentures

目的探讨螺旋桨技术(periodically rotated overlapping parallel lines with enhanced reconstruction,PROPELLER)对金属固定假牙伪影的改善作用。方法收集作者医院2010/2013年核磁共振头颅及上颈椎检查有金属伪影病例86例。根据固定假牙的材质分3组:金铂钯合金组、金银合金组及镍铬合金组。检测3组在核磁共振检查时产生伪影的大小(伪影面积)。应用PROPELLER进行FSE T2WI和扩散加权成像(diffusion-weighted imaging,DWI)与常规T2WI和DWI进行对比。结果金铂钯合金组有轻度伪影;金银合金组、纯钛组有中度伪影;镍铬合金组有重度伪影;不同金属固定材料对核磁共振成像(MRI)的影响不同,伪影程度和材料类型密切相关。结论 PROPELLER明显消除金属磁敏感伪影,提高图像质量和病变检出率,口腔修复材料应尽量少用或不用铁磁性金属材料。

Objective To investigate the role of periodically rotated overlapping parallel lines with enhanced reconstruction( PROPELLER) to improve artifacts of fixed metal dentures. Methods A total of 86 cases with artifacts in skull and upper cervical spine MRI examination in our hospital from 2010 to 2013 were studied. They were divided into three groups according to material of fixed dentures: gold platinum palladium alloy group,gold alloy group,titanium group and nickel-chromium alloy group. The size of artifacts( area of artifacts) of the three groups were detected by FSE T2 WI and diffusion-weighted imaging( DWI) by applying PROPELLER and the method of conventional T2 WI and DWI. The size of artifact acquired by these two method were compared. Results Gold platinum and palladium alloy groups had mild artifacts; gold and silver alloy group,titanium group had moderate artifacts; nickel-chromium alloy group had severe artifacts. Different fixed mental materials had different effects on MRI. The extent of artifacts were closely related to the type of material. Conclusion PROPELLER can significantly eliminate artifacts of metal susceptibility and improve the quality of image and the rate of lesion detection. Dental materials should be minimal or no ferromagnetic metal material.