Wu Ye, Hong Yoonmi, Ahmad Sahar, Yap Pew-Thian
Department of Radiology and Biomedical Research Imaging Center (BRIC), University of North Carolina, Chapel Hill, USA.
Med Image Comput Comput Assist Interv. 2021 Sep-Oct;12907:467-476. doi: 10.1007/978-3-030-87234-2_44. Epub 2021 Sep 21.
Most existing diffusion tractography algorithms are affected by gyral bias, causing the termination of streamlines at gyral crowns instead of sulcal banks. In this paper, we propose a tractography technique, called active cortex tractography (ACT), to overcome gyral bias by enabling fiber streamlines to curve naturally into the cortex. We show that the cortex can play an active role in cortical tractography by providing anatomical information to overcome orientation ambiguities as the streamlines enter the superficial white matter in gyral blades and approach the cortex. This is achieved by devising a direction scouting mechanism that takes into account the white matter surface normal vectors. The scouting mechanism allows probing of directions further in space to prepare the streamlines to turn at appropriate angles. The surface normal vectors guide the streamlines to turn into the cortex, perpendicular to the white-gray matter interface. Evaluation using synthetic, macaque and human data with different streamline seeding schemes demonstrates that ACT improves cortical tractography.
大多数现有的扩散张量纤维束成像算法都受到脑回偏向的影响，导致纤维束在脑回顶部而非脑沟边缘终止。在本文中，我们提出了一种纤维束成像技术，称为主动皮质纤维束成像（ACT），通过使纤维束流线自然地弯曲进入皮质来克服脑回偏向。我们表明，当流线进入脑回叶片中的浅层白质并接近皮质时，皮质可以通过提供解剖学信息来克服方向模糊性，从而在皮质纤维束成像中发挥积极作用。这是通过设计一种考虑白质表面法向量的方向搜索机制来实现的。该搜索机制允许在空间中进一步探测方向，以使流线能够以适当的角度转弯。表面法向量引导流线垂直于白质-灰质界面转向皮质。使用具有不同流线种子点方案的合成数据、猕猴数据和人类数据进行的评估表明，ACT改善了皮质纤维束成像。
