Department of Neuroradiology, University Medical Centre Freiburg, Breisacher St. 64, 79106, Freiburg, Germany,
Clin Neuroradiol. 2013 Dec;23(4):263-75. doi: 10.1007/s00062-013-0198-x. Epub 2013 Jan 18.
Global tracking (GT) is a recently published fibre tractography (FT) method that takes simultaneously all fibres into account during their reconstruction. The purpose of this study was to compare this new method with fibre assignment by continuous tracking (FACT) and probabilistic tractography (PT) for the detection of the corticospinal tract (CST) in patients with gliomas.
Tractography of the CST was performed in 17 patients with eight low grade and nine anaplastic astrocytomas located in the motor cortex or the corticospinal tract. Diffusions metrics as fractional anisotropy (FA), mean (MD), axial (AD) and radial diffusivity (RD) were obtained. The methods were additionally applied on a physical phantom to assess their accuracy.
PT was successful in all (100 %), GT in 16 (94 %) and FACT in 15 patients (88 %). The case where GT and FACT, both, missed the CST showed the highest AD and RD, whereas the one where FACT algorithm, alone, was not successfully showed the lowest AD and RD of the group. FA was reduced on the pathologic side (FApath 0.35 ± 0.16 (mean ± SD) versus FAcontralateral 0.51 ± 0.15, pcorr < 0.03). RD was increased on the pathologic side (RDpath 0.67 ± 0.29 × 10(-3) mm(2)/s versus RDcontralateral 0.46 ± 0.08 × 10(-3) mm(2)/s, pcorr < 0.03). In the phantom measurement, only GT did not detect false positive fibres at fibre crossings.
PT performed well even in areas of increased diffusivities indicating a severe oedema or disintegration of tissue. FACT was also susceptible to a decrease of diffusivities and to a susceptibility artefact, where GT was robust.
全局追踪（GT）是一种最近发表的纤维束追踪（FT）方法，它在重建纤维的过程中同时考虑所有纤维。本研究的目的是比较这种新方法与连续跟踪纤维束追踪（FACT）和概率追踪（PT）在检测胶质瘤患者皮质脊髓束（CST）中的作用。
对 17 例位于运动皮层或皮质脊髓束的 8 例低级别和 9 例间变性星形细胞瘤患者进行 CST 纤维束追踪。获得各向异性分数（FA）、平均（MD）、轴向（AD）和径向扩散系数（RD）等扩散指标。还在物理仿体上应用这些方法来评估它们的准确性。
PT 在所有患者中均成功（100%），GT 在 16 例（94%），FACT 在 15 例（88%）中成功。GT 和 FACT 均未追踪到 CST 的病例 AD 和 RD 值最高，而仅 FACT 算法未成功追踪到 CST 的病例 AD 和 RD 值最低。FA 在病变侧降低（FApath 0.35 ± 0.16（均值 ± SD）比 FAcontralateral 0.51 ± 0.15，pcorr < 0.03）。RD 在病变侧增加（RDpath 0.67 ± 0.29 × 10(-3) mm(2)/s 比 RDcontralateral 0.46 ± 0.08 × 10(-3) mm(2)/s，pcorr < 0.03）。在仿体测量中，只有 GT 没有检测到纤维交叉处的假阳性纤维。
PT 即使在扩散度增加的区域也表现良好，表明存在严重水肿或组织解体。FACT 也容易受到扩散度降低和敏感性伪影的影响，而 GT 则较为稳健。
