Krings T, Chiappa K H, Cuffin B N, Cochius J I, Connolly S, Cosgrove G R
Clinical Neurophysiology Laboratory of the Neurology Service, Massachusetts General Hospital, Boston 02114, USA.
Clin Neurophysiol. 1999 Jan;110(1):106-14. doi: 10.1016/s0013-4694(98)00106-0.
The location of electrical sources in the brain can be estimated by calculating inverse solutions in which the location, amplitude and orientation of the electrical sources are fitted to the scalp EEG. To assess localization accuracy of the moving dipole inverse solution algorithm (ISA), we studied two patients who had depth electrodes implanted for presurgical planning of epilepsy surgery.
Artificial dipoles were created by connecting a single sine wave pulse generator to different pairs of electrodes in multiple orientations and depths. Surface EEG recordings of the resulting pulses were evaluated with the ISA using a 4-shell spherical head model and plotted on the subjects' MRI. Dipole localization errors were evaluated with respect to the number of averaged pulses, different electrode montages and different dipole locations and orientations.
Dipoles located at 40-57 mm from the scalp surface had localization errors that were greater than those located at 62-85 mm. Localization accuracy improved with increasing numbers of pulses and recording electrodes. Results with a standard 10-20 array of 21 electrodes showed an average localization error of 17 mm, whereas 41 electrodes improved this to 13 mm. Mean angular errors were 31 and 30 degrees, respectively.
The ISA was able to differentiate between tangential and radial dipoles. We conclude that our implementation of the ISA is a useful and sound method for localizing electrical activity in the brain.
通过计算逆解来估计脑内电信号源的位置，即将电信号源的位置、幅度和方向与头皮脑电图进行拟合。为评估移动偶极子逆解算法（ISA）的定位准确性，我们研究了两名因癫痫手术术前规划而植入深部电极的患者。
通过将单个正弦波脉冲发生器连接到多个方向和深度的不同电极对上，创建人工偶极子。使用四壳层球形头部模型，通过ISA评估所产生脉冲的头皮脑电图记录，并绘制在受试者的磁共振成像（MRI）上。根据平均脉冲数、不同电极组合以及不同偶极子位置和方向，评估偶极子定位误差。
位于距头皮表面40 - 57毫米处的偶极子定位误差大于位于62 - 85毫米处的偶极子。随着脉冲数和记录电极数量的增加，定位准确性提高。使用标准的21个电极的10 - 20阵列时，平均定位误差为17毫米，而41个电极时将其改善至13毫米。平均角度误差分别为31度和30度。
ISA能够区分切向和径向偶极子。我们得出结论，我们所实现的ISA是一种用于定位脑内电活动的有用且可靠的方法。
