A water-fat separation imaging method for the brain on low field magnetic resonance imaging

Water-fat separation is a particularly important problem for magnetic resonance imaging.Although many methods have been proposed,the reliability is still challenging.In this work,we have presented a method based on the combination of the branch-cut method and multigrid algorithm to get a more robust performance of water-fat separation.First,the branch-cut method is applied to identify residues,which violates the requirement that the interacting phase gradient around a closed path be zero.Residues and branches are marked to be zeros and filled to the weighting factor array.Then,the unwrapped phase array can be given by the multigrid algorithm.Finally,the Dixon method for water-fat separation is applied to the unwrapped phase array.Experiments for brain scanning on the 0.3T low field MRI system demonstrate the successful application of the proposed method.

Dixon水脂分离序列R_(2)*值评估肝铁浓度及鉴别肝结节的研究进展

肝脏肿瘤性病变等多种疾病均可引起铁浓度的改变。MR Dixon水脂分离序列可以通过测量R_(2)*值精准量化人体肝脏及肝内结节的铁浓度,从而判别结节性质及分化程度。介绍Dixon水脂分离序列的成像原理,并就肝铁浓度评估、肝内良恶性结节的鉴别及恶性结节分化程度评估方法的研究进展进行综述。

三维梯度回波Dixon水脂分离序列在产前一周预测胎儿体重中的价值

目的探讨三维梯度回波Dixon水脂分离序列在产前1周预测胎儿体重的价值。方法随机搜集2020年3月至8月本院行MRI检查后1周内分娩的胎儿数据。所有胎儿分娩前1周内均行三维梯度回波Dixon水脂分离序列扫描,把原始图像数据导入星云IX工作站,选择同相位图像进行胎儿分割及三维重组并计算体积,采用Baker方程预测胎儿出生体重,计算预测值与出生体重的误差。结果共纳入23例胎儿数据分析,MRI预测胎儿体重与出生体重的相关性显著(r=0.987,P<0.05);MRI预测胎儿体重与出生体重的平均相对误差为3.98%,相对误差小于5%、10%的比例分别为78%、96%,绝对误差小于100 g、250 g的比例分别为43%、91%;MRI预测体重与出生体重具有较好的一致性,Bland-Altman图示96%的点在95%一致性界限内。结论运用单次屏气三维梯度回波Dixon水脂分离技术预测胎儿体重是可行的,而且扫描时间短,孕妇一次屏气即可完成扫描,能快速、有效地预测胎儿体重。