Translational Imaging Group, Centre for Medical Image Computing (CMIC), Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, London, WC1E 6BT, UK.
NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, 1st Floor, Russell Square House, 10-12 Russell Square, London, WC1B 5EH, UK.
Sci Rep. 2016 Oct 27;6:36151. doi: 10.1038/srep36151.
Axonal loss in the spinal cord is one of the main contributing factors to irreversible clinical disability in multiple sclerosis (MS). In vivo axonal loss can be assessed indirectly by estimating a reduction in the cervical cross-sectional area (CSA) of the spinal cord over time, which is indicative of spinal cord atrophy, and such a measure may be obtained by means of image segmentation using magnetic resonance imaging (MRI). In this work, we propose a new fully automated spinal cord segmentation technique that incorporates two different multi-atlas segmentation propagation and fusion techniques: The Optimized PatchMatch Label fusion (OPAL) algorithm for localising and approximately segmenting the spinal cord, and the Similarity and Truth Estimation for Propagated Segmentations (STEPS) algorithm for segmenting white and grey matter simultaneously. In a retrospective analysis of MRI data, the proposed method facilitated CSA measurements with accuracy equivalent to the inter-rater variability, with a Dice score (DSC) of 0.967 at C2/C3 level. The segmentation performance for grey matter at C2/C3 level was close to inter-rater variability, reaching an accuracy (DSC) of 0.826 for healthy subjects and 0.835 people with clinically isolated syndrome MS.
脊髓中的轴突丧失是多发性硬化症（MS）导致不可逆转的临床残疾的主要因素之一。通过估计脊髓颈段截面积（CSA）随时间的减少，可间接评估体内轴突丧失，这表明脊髓萎缩，并且可以通过使用磁共振成像（MRI）进行图像分割来获得这种测量值。在这项工作中，我们提出了一种新的完全自动化的脊髓分割技术，该技术结合了两种不同的多图谱分割传播和融合技术：用于定位和大致分割脊髓的优化补丁匹配标签融合（OPAL）算法，以及用于同时分割白质和灰质的相似性和传播分割真实性估计（STEPS）算法。在对 MRI 数据的回顾性分析中，该方法以与观察者间变异性相当的准确性实现了 CSA 测量，C2/C3 水平的骰子分数（DSC）为 0.967。C2/C3 水平的灰质分割性能接近观察者间变异性，健康受试者的准确性（DSC）达到 0.826，临床孤立综合征 MS 患者达到 0.835。
