基于局部各向同性假设的磁共振弹性重构算法研究

摘要

Objective To analyze the advantages and disadvantages of various harmonic magnetic resonance elasticity reconstruction algorithms.Methods Different reconstruction algorithms were categorized according to their mathematical hypotheses.The influence of different assumptions on elasticity reconstruction was investigated with experiments and from mathematical fundamentals.Results The finite element full inversion method had higher precision while more computational time.The algorithms with local homogeneity and incompressibility assumptions were faster while less accurate.The algorithms considering the local change of elastic moduli could effectively reduce boundary artifacts.Conclnsion Different assumptions of algorithms may cause levels of errors between the estimated and real elastic moduli.The selection of elasticity reconstruction algorithms in practical experiment requires a comprehensive tradeoff.%目的:研究几种基于各向同性假设的稳态磁共振弹性成像重构算法的优缺点,为方法选择提供参考.方法:将不同算法按其所依据的不同假设进行归类,从数学原理上分析不同算法的优缺点,并使用不同数值仿真实验分析算法中的不同数学假设对弹性重构的影响.结果:使用有限元法全反演的重建结果精度较高,但计算量大.基于弹性模量局部均匀性假设和不可压缩性假设的弹性重构算法计算迅速,但求解精度也较低.而考虑了剪切模量局部变化的算法可以有效降低边界处的伪影.结论:算法中的不同数学假设会导致其弹性重建结果与真实值之间存在不同程度的误差,因此在实际应用中,算法的选取需要进行综合权衡.