Adjamian P, Barnes G R, Hillebrand A, Holliday I E, Singh K D, Furlong P L, Harrington E, Barclay C W, Route P J G
The Wellcome Trust Laboratory for MEG Studies, Neurosciences Research Institute, Aston University, Birmingham B4 7ET, UK.
Clin Neurophysiol. 2004 Mar;115(3):691-8. doi: 10.1016/j.clinph.2003.10.023.
To introduce a new technique for co-registration of Magnetoencephalography (MEG) with magnetic resonance imaging (MRI). We compare the accuracy of a new bite-bar with fixed fiducials to a previous technique whereby fiducial coils were attached proximal to landmarks on the skull.
A bite-bar with fixed fiducial coils is used to determine the position of the head in the MEG co-ordinate system. Co-registration is performed by a surface-matching technique. The advantage of fixing the coils is that the co-ordinate system is not based upon arbitrary and operator dependent fiducial points that are attached to landmarks (e.g. nasion and the preauricular points), but rather on those that are permanently fixed in relation to the skull.
As a consequence of minimizing coil movement during digitization, errors in localization of the coils are significantly reduced, as shown by a randomization test. Displacement of the bite-bar caused by removal and repositioning between MEG recordings is minimal ( approximately 0.5 mm), and dipole localization accuracy of a somatosensory mapping paradigm shows a repeatability of approximately 5 mm. The overall accuracy of the new procedure is greatly improved compared to the previous technique.
The test-retest reliability and accuracy of target localization with the new design is superior to techniques that incorporate anatomical-based fiducial points or coils placed on the circumference of the head.
介绍一种用于脑磁图（MEG）与磁共振成像（MRI）联合配准的新技术。我们将一种带有固定基准点的新型咬棒的准确性与先前的技术进行比较，先前的技术是将基准线圈附着在颅骨上标志点的近端。
使用带有固定基准线圈的咬棒来确定头部在MEG坐标系中的位置。通过表面匹配技术进行联合配准。固定线圈的优点在于坐标系不是基于附着在标志点（如鼻根点和耳前点）上的任意且依赖操作者的基准点，而是基于相对于颅骨永久固定的点。
如随机化测试所示，由于在数字化过程中使线圈移动最小化，线圈定位的误差显著降低。在MEG记录之间因咬棒移除和重新放置导致的位移最小（约0.5毫米），体感映射范式的偶极子定位准确性显示出约5毫米的可重复性。与先前技术相比，新方法的整体准确性有了很大提高。
新设计的目标定位的重测可靠性和准确性优于采用基于解剖学的基准点或放置在头部周围的线圈的技术。
