Roy Snehashis, Butman John A, Pham Dzung L
Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, United States.
Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, United States; Diagnostic Radiology Department, National Institute of Health, United States.
Neuroimage. 2017 Feb 1;146:132-147. doi: 10.1016/j.neuroimage.2016.11.017. Epub 2016 Nov 15.
Automatic skull-stripping or brain extraction of magnetic resonance (MR) images is often a fundamental step in many neuroimage processing pipelines. The accuracy of subsequent image processing relies on the accuracy of the skull-stripping. Although many automated stripping methods have been proposed in the past, it is still an active area of research particularly in the context of brain pathology. Most stripping methods are validated on T-w MR images of normal brains, especially because high resolution T-w sequences are widely acquired and ground truth manual brain mask segmentations are publicly available for normal brains. However, different MR acquisition protocols can provide complementary information about the brain tissues, which can be exploited for better distinction between brain, cerebrospinal fluid, and unwanted tissues such as skull, dura, marrow, or fat. This is especially true in the presence of pathology, where hemorrhages or other types of lesions can have similar intensities as skull in a T-w image. In this paper, we propose a sparse patch based Multi-cONtrast brain STRipping method (MONSTR), where non-local patch information from one or more atlases, which contain multiple MR sequences and reference delineations of brain masks, are combined to generate a target brain mask. We compared MONSTR with four state-of-the-art, publicly available methods: BEaST, SPECTRE, ROBEX, and OptiBET. We evaluated the performance of these methods on 6 datasets consisting of both healthy subjects and patients with various pathologies. Three datasets (ADNI, MRBrainS, NAMIC) are publicly available, consisting of 44 healthy volunteers and 10 patients with schizophrenia. Other three in-house datasets, comprising 87 subjects in total, consisted of patients with mild to severe traumatic brain injury, brain tumors, and various movement disorders. A combination of T-w, T-w were used to skull-strip these datasets. We show significant improvement in stripping over the competing methods on both healthy and pathological brains. We also show that our multi-contrast framework is robust and maintains accurate performance across different types of acquisitions and scanners, even when using normal brains as atlases to strip pathological brains, demonstrating that our algorithm is applicable even when reference segmentations of pathological brains are not available to be used as atlases.
磁共振(MR)图像的自动颅骨剥离或脑提取通常是许多神经图像处理流程中的基本步骤。后续图像处理的准确性依赖于颅骨剥离的准确性。尽管过去已经提出了许多自动剥离方法,但它仍然是一个活跃的研究领域,特别是在脑病理学背景下。大多数剥离方法是在正常大脑的T加权MR图像上进行验证的,尤其是因为高分辨率T加权序列被广泛采集,并且正常大脑的地面真相手动脑掩码分割是公开可用的。然而,不同的MR采集协议可以提供有关脑组织的补充信息,这可以用于更好地区分脑、脑脊液和不需要的组织,如颅骨、硬脑膜、骨髓或脂肪。在存在病理学的情况下尤其如此,其中出血或其他类型的病变在T加权图像中可能具有与颅骨相似的强度。在本文中,我们提出了一种基于稀疏补丁的多对比度脑剥离方法(MONSTR),其中来自一个或多个图谱的非局部补丁信息(包含多个MR序列和脑掩码的参考描绘)被组合以生成目标脑掩码。我们将MONSTR与四种最先进的公开可用方法进行了比较:BEaST、SPECTRE、ROBEX和OptiBET。我们在由健康受试者和患有各种病理学疾病的患者组成的6个数据集上评估了这些方法的性能。三个数据集(ADNI、MRBrainS、NAMIC)是公开可用的,由44名健康志愿者和10名精神分裂症患者组成。其他三个内部数据集总共包括87名受试者,由轻度至重度创伤性脑损伤、脑肿瘤和各种运动障碍患者组成。使用T加权、T加权的组合对这些数据集进行颅骨剥离。我们表明,在健康和病理大脑上,与竞争方法相比,剥离有显著改进。我们还表明,我们的多对比度框架是稳健的,并且在不同类型的采集和扫描仪中保持准确的性能,即使使用正常大脑作为图谱来剥离病理大脑,这表明即使没有病理大脑的参考分割可用作图谱,我们的算法也是适用的。