Department of Neuroradiology, S Andrea Hospital, University Sapienza, Rome, Italy.
Neurosurgery. 2011 Sep;69(3):696-704; discussion 704-5. doi: 10.1227/NEU.0b013e31821a8555.
Magnetic resonance with diffusion tensor image (DTI) may be able to estimate trajectories compatible with subcortical tracts close to brain lesions. A limit of DTI is brain shifting (movement of the brain after dural opening and tumor resection).
To calculate the brain shift of trajectories compatible with the corticospinal tract (CST) in patients undergoing glioma resection and predict the shift directions of CST.
DTI was acquired in 20 patients and carried out through 12 noncollinear directions. Dedicated software "merged" all sequences acquired with tractographic processing and the whole dataset was sent to the neuronavigation system. Preoperative, after dural opening (in 11) and tumor resection (in all) DTI acquisitions were performed to evaluate CST shifting. The extent of shifting was considered as the maximum distance between the preoperative and intraoperative contours of the trajectories.
An outward shift of CST was observed in 8 patients and an inward shift in 10 patients during surgery. In the remaining 2 patients, no intraoperative displacement was detected. Only peritumoral edema showed a statistically significant correlation with the amount of shift. In those patients in which DTI was acquired after dural opening as well (11 patients), an outward shifting of CST was evident in that phase.
The use of intraoperative DTI demonstrated brain shifting of the CST. DTI evaluation of white matter tracts can be used during surgical procedures only if updated with intraoperative acquisitions.
磁共振弥散张量成像（DTI）可用于估计与靠近脑损伤的皮质下束相兼容的轨迹。DTI 的一个局限性是脑移位（硬脑膜切开和肿瘤切除后大脑的移动）。
计算行胶质瘤切除术患者的皮质脊髓束（CST）相容轨迹的脑移位，并预测 CST 的移位方向。
对 20 例患者进行了 DTI 采集，并进行了 12 个非共线方向的采集。专用软件“合并”了所有通过轨迹处理获得的序列，并将整个数据集发送到神经导航系统。在术前、硬脑膜切开后（11 例）和肿瘤切除后（所有病例）进行 DTI 采集，以评估 CST 移位。移位的程度被认为是术前和术中轨迹轮廓之间的最大距离。
8 例患者在手术中观察到 CST 向外移位，10 例患者向内移位。在另外 2 例患者中，术中未检测到移位。只有瘤周水肿与移位量呈显著相关。在那些术后也进行了 DTI 采集的患者中（11 例），在该阶段也观察到 CST 向外移位。
术中 DTI 显示 CST 发生脑移位。只有在更新术中采集的情况下，才能在手术过程中使用 DTI 评估白质束。
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