Seow Pohchoo, Hernowo Aditya T, Narayanan Vairavan, Wong Jeannie Hsiu Ding, Bahuri Nor Faizal Ahmad, Cham Chun Yoong, Abdullah Nor Aniza, Kadir Khairul Azmi Abdul, Rahmat Kartini, Ramli Norlisah
Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Department of Diagnostic Radiology, Singapore General Hospital, Singapore.
Department of Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Acad Radiol. 2021 Dec;28(12):1721-1732. doi: 10.1016/j.acra.2020.09.007. Epub 2020 Oct 3.
Gliomatous tumors are known to affect neural fiber integrity, either by displacement or destruction. The aim of this study is to investigate the integrity and distribution of the white matter tracts within and around the glioma regions using probabilistic fiber tracking.
Forty-two glioma patients were subjected to MRI using a standard tumor protocol with diffusion tensor imaging (DTI). The tumor and peritumor regions were delineated using snake model with reference to structural and diffusion MRI. A preprocessing pipeline of the structural MRI image, DTI data, and tumor regions was implemented. Tractography was performed to delineate the white matter (WM) tracts in the selected tumor regions via probabilistic fiber tracking. DTI indices were investigated through comparative mapping of WM tracts and tumor regions in low-grade gliomas (LGG) and high-grade gliomas (HGG).
Significant differences were seen in the planar tensor (C) in peritumor regions; mean diffusivity, axial diffusivity and pure isotropic diffusion in solid-enhancing tumor regions; and fractional anisotropy, axial diffusivity, pure anisotropic diffusion (q), total magnitude of diffusion tensor (L), relative anisotropy, C and spherical tensor (C) in solid nonenhancing tumor regions for affected WM tracts. In most cases of HGG, the WM tracts were not completely destroyed, but found intact inside the tumor.
Probabilistic fiber tracking revealed the existence and distribution of WM tracts inside tumor core for both LGG and HGG groups. There were more DTI indices in the solid nonenhancing tumor region, which showed significant differences between LGG and HGG.
已知胶质瘤会通过移位或破坏来影响神经纤维的完整性。本研究旨在使用概率纤维追踪技术研究胶质瘤区域内及周围白质束的完整性和分布情况。
42例胶质瘤患者接受了采用标准肿瘤方案及扩散张量成像（DTI）的MRI检查。参照结构MRI和扩散MRI，使用蛇形模型勾勒出肿瘤及瘤周区域。实施了结构MRI图像、DTI数据和肿瘤区域的预处理流程。通过概率纤维追踪技术在选定的肿瘤区域描绘白质（WM）束。通过对低级别胶质瘤（LGG）和高级别胶质瘤（HGG）中WM束与肿瘤区域的对比映射来研究DTI指标。
在瘤周区域的平面张量（C）、实性强化肿瘤区域的平均扩散率、轴向扩散率和纯各向同性扩散、以及实性非强化肿瘤区域中受影响WM束的分数各向异性、轴向扩散率、纯各向异性扩散（q）、扩散张量的总大小（L）、相对各向异性、C和球形张量（C）方面均观察到显著差异。在大多数HGG病例中，WM束并未完全被破坏，而是在肿瘤内部保持完整。
概率纤维追踪显示LGG和HGG组肿瘤核心内部均存在WM束并明确了其分布情况。实性非强化肿瘤区域中有更多的DTI指标，且在LGG和HGG之间显示出显著差异。
