双张量无损卡尔曼滤波纤维束示踪技术优化显像皮质脊髓束及其可靠性研究

Corticospinal tract (CST) is the most important tract on controlling the voluntary movement of the extremities. Conventional DTI techniques are unable to trace the lateral projections of CST that link to hand-related functional cortex and inadequate to reconstruct the tracts in the regions of peritumoral edema and should be improved or replaced by other new techniques. Two-tensor unscented Kalman filter tractography (2t UKFT) is a relatively new technique on reconstruction of fiber bundles. A recent study abroad and our preliminary results show that 2t UKFT can dipict a more complete CST and has the advantages on tracing CST in the regions of peritumoral edema, but its optimized parameters about CST reconstruction and the validity of that still need further study. With this prospective self-controlled study, we plan to dipict CST before and after the surgery intervention, and correlate the change of subjects' motor function with the change of fiber number of CST reconstructed by the method of 2t UKFT with different parameters. In this way, we sought to screen out the optimized parameters of 2t UKFT on dipicting CST and perform a preliminary investigation on the reliability of this technique. This study may offer us a new method to visualize CST in pathological status and lay a foundation for the study on the validity of fiber reconstruction with 2t UKFT compared with “gold standerd” intraoperative electric stimulation.

皮质脊髓束（CST）是最重要的支配四肢随意运动的功能传导束。临床常用的弥散张量纤维束示踪技术无法重建CST的上肢投射部分，并且在重建瘤周水肿区的CST方面具有局限性，亟待改进或新技术的研发。双张量无损卡尔曼滤波纤维束示踪技术（2t UKFT）是一种较新的纤维束重建技术。近期的一项国外研究和我们的预实验均表明，2t UKFT可以较完整地重建CST，并且在重建瘤周水肿区的CST方面具有优势，但其优化显像参数和可靠性仍需进一步研究。因此，本项目拟采用前瞻性对比试验，利用不同参数下的2t UKFT在外科干预前后重建累及CST并伴瘤周水肿的研究对象的CST，并将术前术后不同参数下重建的纤维束变化与运动功能变化相关联，旨在获取2t UKFT重建CST的优化显像参数并初步探讨其可靠性。本研究将为我们观察病理状态下的CST提供一个新方法，并为“金标准”术中电刺激验证该法重建纤维束的可靠性奠定基础。

应用传统常规的纤维束成像技术重建皮质脊髓束的扇形分布纤维（尤其是投射到中央前回上肢和面部皮层区的部分）和瘤周水肿区纤维具有局限性，亟需一种更好的纤维束重建技术来解决上述局限性。本研究旨在研究一种名为双张量无损卡尔曼滤波纤维束示踪技术在重建皮质脊髓束方面的优越性。本研究表明：1.双张量无损卡尔曼滤波纤维束示踪技术比传统的纤维束成像技术能够重建出更多的投射到中央前回上肢和面部皮层区的纤维和瘤周水肿区纤维；2.影响双张量无损卡尔曼滤波纤维束示踪技术重建皮质脊髓束的重要因素是广义各项异性的参数选择（建议至0.075）和种子点选择策略（建议在全脑纤维束重建的基础上再选择纤维束走形区的种子点），而部分各项异性的参数和自由水模型的选择影响较小。双张量无损卡尔曼滤波纤维束示踪技术相对于传统的纤维束成像技术虽然有一定优势，但是仍然有其局限性，仍然需要探索和寻找能够完全真实反映大脑纤维的理想的纤维束成像技术。