【摘要】 在核磁共振成像中,涡流的存在会影响系统的成像质量。梯度电流预增强方法是一种被广泛采用的有效的涡流补偿方法。梯度电流预增强在一个周期内要进行上千次e指数计算,需采用快速的计算方法。迭代计算是普遍采用的涡流补偿快速计算方法,但是存在累积误差放大的问题。针对这种问题,基于迭代计算原理,我们提出了一种改进的分段迭代的MRI成像涡流补偿计算方法。实验结果表明,在计算时间同量级的条件下有效地提高了梯度预增强量的精度。更多还原

【Abstract】 The eddy current will affect the imaging quality in magnetic resona nce imaging systems.The pre-emphasis of gradient current is an efficient method and is widely used in eddy current compensation.Pre-emphasis of gradient curre nt needs thousands of exponential calculation in a single cycle.So it is impera tive to use a rapid method.Iteration calculation is generally used in eddy curr ent compensation.However,accumulated error will be amplified with the number o f iterations.In order to solve the problem,based on the fundamental of iterati on calculation,an improved iterative segmentation calculation algorithm of eddy current compensation is presented in this paper.The experiments prove that the accuracy of the pre-emphasis of gradient current is improved effectively with a run-time in the same order of magnitude.更多还原