Simon Jack H, Zhang Song, Laidlaw David H, Miller David E, Brown Mark, Corboy John, Bennett Jeffrey
Department of Radiology, University of Colorado, Denver, Colorado 80252, USA.
J Magn Reson Imaging. 2006 Nov;24(5):983-8. doi: 10.1002/jmri.20719.
Focal inflammatory/demyelinating lesions are thought to be the source of Wallerian degeneration or other injury to local, transiting fiber tracts in the brain or spinal cord in multiple sclerosis (MS). A methodology is established to isolate connections between focal demyelinating lesions and intersecting fibers to permit explicit analyses of the pathology of secondary fiber injury distant from the focal lesion.
A strategy is described and feasibility demonstrated in three patients with a clinically isolated syndrome and positive MRI (at high risk for MS). The strategy utilizes streamtube diffusion tractography to identify neuronal fibers that intersect a focal lesion and pass through a region of interest, in this case the corpus callosum, where distal (to focal lesion) interrogation can be accomplished.
A sizeable fraction of the normal appearing white matter (NAWM) in the early stages of disease can be defined in the corpus callosum, which is distinctive in that this tissue connects to distant demyelinating lesions.
The new class of tissue called fibers-at-risk for degeneration (FAR) can be identified and interrogated by a variety of quantitative MRI methodologies to better understand neuronal degeneration in MS.
局灶性炎症/脱髓鞘病变被认为是多发性硬化症（MS）中脑或脊髓局部、穿行纤维束沃勒变性或其他损伤的来源。建立了一种方法来分离局灶性脱髓鞘病变与交叉纤维之间的联系，以便对远离局灶性病变的继发性纤维损伤的病理学进行明确分析。
描述了一种策略，并在三名临床孤立综合征且MRI阳性（MS高危）患者中证明了其可行性。该策略利用流管扩散张量成像来识别与局灶性病变相交并穿过感兴趣区域（在本例中为胼胝体）的神经元纤维，在该区域可以完成对（远离局灶性病变的）远端的询问。
在疾病早期，胼胝体中相当一部分外观正常的白质（NAWM）可以被界定，其独特之处在于该组织与远处的脱髓鞘病变相连。
可以通过多种定量MRI方法识别和询问一种名为“有变性风险的纤维”（FAR）的新组织类别，以更好地理解MS中的神经元变性。
