Motor and language DTI Fiber Tracking combined with intraoperative subcortical mapping for surgical removal of gliomas

Preoperative DTI Fiber Tracking (DTI-FT) reconstruction of functional tracts combined with intraoperative subcortical mapping (ISM) is potentially useful to improve surgical procedures in gliomas located in eloquent areas. Aims of the study are: (1) to evaluate the modifications of fiber trajectory induced by the tumor; (2) to validate preoperative DTI-FT results with intraoperative identification of functional subcortical sites through direct subcortical stimulation; (3) to evaluate the impact of preoperative DTI-FT reconstructions in a neuronavigational setup combined with ISM technique on duration and modalities of surgical procedures, and on functional outcome of the patients.Data are available on 64 patients (52 low-grade and 12 high-grade gliomas). DTI-FT was acquired by a 3-T MR scanner with a single-shot EPI sequence (TR/TE 8986/80 ms, b=1000 s/mm) with gradients applied along 32 non-collinear directions. 3D Fast Field Echo (FFE) T1-weighted imaging (TR/TE 8/4 ms) was performed for anatomic guidance. The corticospinal tract (CST), superior longitudinal, inferior fronto-occipital and uncinatus fasciculi were reconstructed. Data were transferred to the neuronavigational system. Functional subcortical sites identified during ISM were correlated with fiber tracts depicted by DTI-FT.In high-grade gliomas, DTI-FT depicted tracts mostly at the tumor periphery; in low-grade gliomas, fibers were frequently located inside the tumor mass. There was a high correlation between DTI-FT and ISM (sensitivity for CST=95%, language tracts=97%). For a proper reconstruction of the tracts, it was necessary to use a low FA threshold of fiber tracking algorithm and to position additional regions of interest (ROIs). The combination of DTI-FT and ISM decreased the duration of surgery, patient fatigue, and intraoperative seizures.Combination of DTI-FT and ISM allows accurate identification of eloquent fiber tracts and enhances surgical performance and safety maintaining a high rate of functional preservation. (C) 2007 Elsevier Inc. All rights reserved.

术前对功能束进行弥散张量成像纤维束示踪（DTI - FT）重建并结合术中皮质下映射（ISM），对于改善位于功能区的胶质瘤的手术过程可能是有用的。本研究的目的是：（1）评估肿瘤引起的纤维轨迹的改变；（2）通过直接皮质下刺激在术中识别功能性皮质下位点来验证术前DTI - FT结果；（3）评估在神经导航设置下结合ISM技术的术前DTI - FT重建对手术过程的持续时间和方式以及患者功能预后的影响。有64例患者（52例低级别胶质瘤和12例高级别胶质瘤）的数据可用。DTI - FT是通过3T磁共振扫描仪使用单次激发平面回波成像序列（重复时间/回波时间8986/80毫秒，b = 1000秒/平方毫米）获取的，梯度沿32个非共线方向施加。进行3D快速场回波（FFE）T1加权成像（重复时间/回波时间8/4毫秒）以提供解剖学指导。重建了皮质脊髓束（CST）、上纵束、额枕下束和钩束。数据被传输到神经导航系统。ISM过程中识别的功能性皮质下位点与DTI - FT所描绘的纤维束相关。在高级别胶质瘤中，DTI - FT所描绘的纤维束大多位于肿瘤周边；在低级别胶质瘤中，纤维常常位于肿瘤肿块内部。DTI - FT和ISM之间有高度相关性（皮质脊髓束的敏感度为95%，语言束为97%）。为了正确重建纤维束，有必要使用低的纤维束示踪算法的各向异性分数阈值并设置额外的感兴趣区域（ROIs）。DTI - FT和ISM的结合减少了手术时间、患者疲劳以及术中癫痫发作。DTI - FT和ISM的结合能够准确识别功能纤维束，并提高手术效果和安全性，同时保持较高的功能保留率。（C）2007爱思唯尔公司。保留所有权利。