Department of Radiology, Johns Hopkins University, Baltimore, MD 21287, USA.
Neuroimage. 2010 Feb 15;49(4):3047-56. doi: 10.1016/j.neuroimage.2009.11.043. Epub 2009 Nov 26.
Diffusion-tensor-imaging fiber tractography enables interrogation of brain white matter tracts that subserve different functions. However, tract reconstruction can be labor and time intensive and can yield variable results that may reduce the power to link imaging abnormalities with disability. Automated segmentation of these tracts would help make tract-specific imaging clinically useful, but implementation of such segmentation is problematic in the presence of diseases that alter brain structure. In this work, we investigated an automated tract-probability-mapping scheme and applied it to multiple sclerosis, comparing the results to those derived from conventional tractography. We found that the automated method has consistently lower scan-rescan variability (typically 0.7-1.5% vs. up to 3% for conventional tractography) and avoids problems related to tractography failures within and around lesions. In the corpus callosum, optic radiation, and corticospinal tract, tract-specific MRI indices calculated by the two methods were moderately to strongly correlated, though systematic, tract-specific differences were present. In these tracts, the two methods also yielded similar correlation coefficients relating tract-specific MRI indices to clinical disability scores. In the optic tract, the automated method failed. With judicious application, therefore, the automated method may be useful for studies that investigate the relationship between imaging findings and clinical outcomes in disease.
弥散张量成像纤维束追踪技术可用于研究大脑白质束，这些白质束负责不同的功能。然而，束重建既费时又费力，而且结果可能存在差异，从而降低了将影像学异常与残疾联系起来的能力。这些束的自动分割将有助于使束特异性成像具有临床意义，但在存在改变大脑结构的疾病的情况下，这种分割的实现存在问题。在这项工作中，我们研究了一种自动束概率映射方案，并将其应用于多发性硬化症，将结果与传统束追踪的结果进行比较。我们发现，自动方法的扫描-重扫可变性始终较低（通常为 0.7-1.5%，而传统束追踪方法为 3%），并且避免了与病变内和周围的束追踪失败相关的问题。在胼胝体、视辐射和皮质脊髓束中，两种方法计算的束特异性 MRI 指数具有中度至强相关性，但存在系统的束特异性差异。在这些束中，两种方法还得出了与临床残疾评分相关的束特异性 MRI 指数的相似相关系数。在视束中，自动方法失败了。因此，通过谨慎应用，该自动方法可能有助于研究疾病中影像学发现与临床结果之间的关系。
