磁共振伪影简介

GEMedicalSystemsTraininginPartnership磁共振常见伪影GEMedicalSystemsTraininginPartnership内容…伪影分类...伪影产生的原因及解决方案.........GEMedicalSystemsTraininginPartnership内容…伪影分类...伪影产生的原因及解决方案.........GEMedicalSystemsTraininginPartnership常见伪影•射频相关的伪影•梯度相关的伪影•主磁场相关的伪影•图像处理相关的伪影•患者相关的伪影•操作者相关的伪影GEMedicalSystemsTraininginPartnership射频相关伪影•周围环境的射频干扰–汽车，电话，其他电动工具，高压注射器，灯丝在运行时也会产生电磁波，干扰磁共振的射频脉冲–磁体间临近磁体间临近马路、停车场、地铁站–伪影在相位方向上–伪影的位置会随着带宽的增大而向图像中心移动•必须找工程师解决GEMedicalSystemsTraininginPartnership射频相关伪影GEMedicalSystemsTraininginPartnership射频相关伪影•RF溢出–采集的信号过强，在模数转化时无法精确地数字化–MRCP时出现这种伪影，可以在imageoption中加上EDR–其他部位扫描出现这种情况，点击manualprescan,在其中手动调节TGGEMedicalSystemsTraininginPartnership梯度相关伪影•矢冠状图像变形–梯度场切换率过高–未使用梯度线性校正•缩小扫描视野•打开梯度线性校正GEMedicalSystemsTraininginPartnership梯度相关伪影•Eddycurrent伪影GEMedicalSystemsTraininginPartnershipDWIXYZ梯度相关伪影GEMedicalSystemsTraininginPartnership梯度相关伪影•梯度线圈损坏GEMedicalSystemsTraininginPartnership梯度相关伪影GEMedicalSystemsTraininginPartnership图像处理相关伪影•Spike伪影–K空间中出现错误数据•重新扫描，如果伪影持续存在，请联系工程师GEMedicalSystemsTraininginPartnership图像处理相关伪影•化学伪影伪影–出现在脂肪与水的交界面处–出现在频率方向–一侧表现为高信号线，另一侧为低信号线•解决方法是增大采样带宽GEMedicalSystemsTraininginPartnership图像处理相关伪影•化学位移伪影GEMedicalSystemsTraininginPartnership图像处理相关伪影•Gibbs伪影–相位或频率方向数据采集不足–表现为与边界平行的黑色或白色的线•解决方法是增大扫描矩阵，降低扫描FOV128*128256*256GEMedicalSystemsTraininginPartnership图像处理相关伪影•Gibbs伪影GEMedicalSystemsTraininginPartnership图像处理相关伪影•Annefect伪影–扫描视野过小时，翻转相位方向–扫描视野与线圈范围严重不匹配•增大扫描视野或调整线圈与扫描视野相匹配GEMedicalSystemsTraininginPartnership图像处理相关伪影•Aliasing伪影GEMedicalSystemsTraininginPartnership图像处理相关伪影•Aliasing伪影GEMedicalSystemsTraininginPartnership磁敏感性伪影•局部磁场不均匀引起的EPI图像变形GEMedicalSystemsTraininginPartnership磁敏感性伪影•局部磁场不均匀引起的常规图像变形GEMedicalSystemsTraininginPartnership磁敏感性伪影GEMedicalSystemsTraininginPartnership磁敏感性伪影•局部磁场不均匀引起脂肪抑制异常GEMedicalSystemsTraininginPartnership磁敏感性伪影•局部磁场不均匀引起图像伪影GEMedicalSystemsTraininginPartnership磁敏感性伪影•磁敏感伪影–扫描时患者上肢没有上举GEMedicalSystemsTraininginPartnership磁敏感性伪影•扫描视野过大•降低TE，降低ETLGEMedicalSystemsTraininginPartnership患者相关伪影•Magicangle效应–肌腱与主磁场成55度夹角时会表现为异常高信号–主要出现在T1和PD图像上，T2会明显衰减GEMedicalSystemsTraininginPartnership1333参数相关伪影•修改ETLGEMedicalSystemsTraininginPartnership1333参数相关伪影•修改ETL1541GEMedicalSystemsTraininginPartnership参数相关伪影•修改带宽1541GEMedicalSystemsTraininginPartnership参数相关伪影•定位线交叉GEMedicalSystemsTraininginPartnership参数相关伪影•定位线交叉GEMedicalSystemsTraininginPartnership参数相关伪影•Phasecorrection打开或关闭GEMedicalSystemsTraininginPartnership参数相关伪影•PURE伪影线圈摆放错误线圈单元损坏GEMedicalSystemsTraininginPartnership参数相关伪影•修改NEXGEMedicalSystemsTraininginPartnership参数相关伪影•频率方向错误GEMedicalSystemsTraininginPartnership总结•出现伪影，首先明确伪影的性质•排除操作原因•寻求工程师帮助GEMedicalSystemsTraininginPartnership谢谢