A FAST METHOD FOR FORWARD COMPUTATION OF MULTIPLE-SHELL SPHERICAL HEAD MODELS
A FAST METHOD FOR FORWARD COMPUTATION OF MULTIPLE-SHELL SPHERICAL HEAD MODELS
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DOI：
10.1016/0013-4694(94)90113-9
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发表时间：
1994-01-01
期刊：
影响因子：
--
通讯作者：
SCHERG, M
中科院分区：
文献类型：
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作者：
BERG, P;SCHERG, M
使用3个适当定位的偶极子在一个均匀的球的组合，由于偶极子源在一个4壳球头模型的头皮电位可以近似与高精度和超过30倍的计算速度增加。3个等效偶极的幅度和位置可以在均匀球体中拟合到从4壳头部模型中的一个位置处的源生成的数据。所得到的参数被用来计算头皮电位源在其他位置和方向。残差方差的措施表现出密切的协议之间的新的近似和标准的4壳计算方法。该方法的进一步测试使用头皮数据从500个随机选择的来源对产生的标准4壳计算和拟合，向前计算，新的近似和单壳Ary校正的头部模型。新近似的误差略大于标准计算，但在99%的拟合中，源位于原始位置的0.5 mm和0.6度范围内。Ary模型的99%误差限值高达18 mm和25度，并取决于头部模型参数。
Using a combination of 3 suitably located dipoles in a homogeneous sphere, the scalp potential due to a dipole source in a 4-shell spherical head model can be approximated with a high degree of precision and a more than 30-fold increase in computing speed. Magnitudes and locations of the 3 equivalent dipoles can be fitted in a homogeneous sphere to data generated from a source at one location in a 4-shell head model. The resulting parameters are used to compute scalp potentials for sources at other locations and orientations. Residual variance measures showed close agreement between the new approximation and a standard 4-shell computation method. Further tests of the method used scalp data from 500 randomly selected pairs of sources generated by the standard 4-shell computation and fitted using, for forward computations, the new approximation and the single-shell Ary-corrected head model. Errors with the new approximation were marginally larger than with the standard computation, but sources were located within 0.5 mm and 0.6 degrees of the original position in 99% of the fits. 99% error limits for the Ary model were up to 18 mm and 25 degrees and depended on the head model parameters.