Investigating cervical spinal cord structure using axial diffusion tensor imaging
Investigating cervical spinal cord structure using axial diffusion tensor imaging
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DOI：
10.1006/nimg.2001.1022
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发表时间：
2002-05-01
期刊：
影响因子：
5.7
通讯作者：
Barker, GJ
中科院分区：
文献类型：
--
作者：
Wheeler-Kingshott, CAM;Hickman, SJ;Barker, GJ
这项研究描述了一种弥散张量成像 (DTI) 新技术，可获取颈脊髓的轴向（横向）图像。 DTI 图像描绘了轴突纤维方向，能够量化沿脊髓的扩散特征，并有可能证明脊髓白质束的连接性。由于扩散加权磁共振成像对运动的高敏感性和脊髓的小尺寸，开发了一种具有高面内分辨率的快速成像方法。图像是通过单次 EPI 技术获取的，称为 ZOOM-EPI（分区放大倾斜多层回波平面成像），该技术选择局部区域并减少由软组织和相邻椎骨之间磁敏感度变化引起的伪影。心脏门控用于减少周围脑脊液的脉动流伪影。面内体素分辨率为 1.25 x 1.25 mm(2)，切片厚度为 5 mm。测量颈脊髓的平均扩散率（MD）和分数各向异性（FA）指数。 FA 指数显示脊髓具有高度各向异性，平均值为 0.61 +/- 0.05（C3 处的最高值为 0.66 +/- 0.03），与大脑中的白质束相当。平行和正交于帘线纵轴的扩散系数分量分别为 lambda(垂直于) = (1648 +/- 123) x 10(-6) mm(2)s(-1) 和 lambda = (570 +/- 47) x 10(-6) mm(2) s(-1)。高轴向分辨率允许使用快速行进纤维束成像算法对纤维连接性进行初步评估，该算法生成与众所周知的绳索解剖结构一致的纤维路径痕迹。 (C) 2002 年爱思唯尔科学（美国）。
This study describes a new technique for Diffusion Tensor Imaging (DTI) that acquires axial (transverse) images of the cervical spinal cord. The DTI images depict axonal fiber orientation, enable quantification of diffusion characteristics along the spinal cord, and have the potential to demonstrate the connectivity of cord white matter tracts. Because of the high sensitivity to motion of diffusion-weighted magnetic resonance imaging and the small size of the spinal cord, a fast imaging method with high in-plane resolution was developed. Images were acquired with a single-shot EPI technique, named ZOOM-EPI (zonally magnified oblique multislice echo planar imaging), which selects localized areas and reduces artefacts caused by susceptibility changes between soft tissue and the adjacent vertebrae. Cardiac gating was used to reduce pulsatile flow artefacts from the surrounding cerebrospinal fluid. Voxel resolution was 1.25 x 1.25 mm(2) in-plane with 5-mm slice thickness. Both the mean diffusivity (MD) and the fractional anisotropy (FA) indices of the cervical spinal cord were measured. The FA index demonstrated high anisotropy of the spinal cord with an average value of 0.61 +/- 0.05 (highest value of 0.66 +/- 0.03 at C3), comparable to white matter tracts in the brain. The diffusivity components parallel and orthogonal to the longitudinal axes of the cord were lambda(perpendicular to) = (1648 +/- 123) x 10(-6) mm(2)s(-1) and lambda = (570 +/- 47) x 10(-6) mm(2) s(-1), respectively. The high axial resolution allowed preliminary evaluation of fiber connectivity using the fast-marching tractography algorithm, which generated traces of fiber paths consistent wit the well-known cord anatomy. (C) 2002 Elsevier Science (USA).