Alexander E, Kooy H M, van Herk M, Schwartz M, Barnes P D, Tarbell N, Mulkern R V, Holupka E J, Loeffler J S
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
J Neurosurg. 1995 Aug;83(2):271-6. doi: 10.3171/jns.1995.83.2.0271.
Distortions of the magnetic field, such as those caused by susceptibility artifacts and peripheral magnetic field warping, can limit geometric precision in the use of magnetic resonance (MR) imaging in stereotactic procedures. The authors have routinely found systematic error in MR stereotactic coordinates with a median of 4 mm compared to computerized tomography (CT) coordinates. This error may place critical neural structures in jeopardy in sme procedures. A description is given of an image fusion technique that uses a chamfer matching algorithm; the advantages of MR imaging in anatomical definition are combined with the geometric precision of CT, while eliminating most of the anatomical spatial distortion of stereotactic MR imaging. A stereotactic radiosurgical case is presented in which the use of MR localization alone would have led to both irradiation of vital neural structures outside the desired target volume and underdose of the intended target volume. The image fusion approach allows for the use of MR imaging, combined with stereotactic CT, as a reliable localizing technique for stereotactic neurosurgery and radiosurgery.
磁场畸变，如由磁化率伪影和外周磁场扭曲所引起的畸变，会限制立体定向手术中磁共振（MR）成像使用时的几何精度。作者经常发现，与计算机断层扫描（CT）坐标相比，MR立体定向坐标存在系统误差，中位数为4毫米。在某些手术中，这种误差可能会使关键神经结构处于危险之中。本文介绍了一种使用倒角匹配算法的图像融合技术；将MR成像在解剖结构定义方面的优势与CT的几何精度相结合，同时消除了立体定向MR成像中的大部分解剖学空间畸变。本文展示了一个立体定向放射外科病例，其中仅使用MR定位会导致重要神经结构在期望靶体积之外受到照射，而期望靶体积剂量不足。图像融合方法允许将MR成像与立体定向CT相结合，作为立体定向神经外科手术和放射外科手术的可靠定位技术。
