Pike G B, De Stefano N, Narayanan S, Worsley K J, Pelletier D, Francis G S, Antel J P, Arnold D L
McConnell Brain Imaging Center, Montreal Neurological Institute, 3801 University St, Montreal, Québec, Canada.
Radiology. 2000 Jun;215(3):824-30. doi: 10.1148/radiology.215.3.r00jn02824.
To determine the evolution of magnetization transfer (MT) in white matter regions before and after plaque development in patients with multiple sclerosis (MS).
In a 5-year longitudinal evaluation, 30 patients with MS underwent conventional magnetic resonance (MR) imaging, MT MR imaging, and clinical assessment. Cross-sectional data in 12 healthy subjects were also collected. Semiautomated lesion classification with use of T2-weighted MR images was used to measure the time course of the MT ratio (calculated with MR data acquired without and with MT saturation) in every voxel and to help analyze the relationship with the status of lesions depicted on T2-weighted images.
There was a significant (P <.001) temporal decline in lesion MT ratio after lesion appearance on T2-weighted images. A significant (P <. 001) progressive decline in MT ratio was also present in voxels that later became lesions, prior to initial detection on T2-weighted images. Even 1(1/2) years prior to lesion appearance, the MT ratio (33.3%) in regions destined to become such lesions was significantly (P <.001) lower than that in both white matter in healthy subjects (41.3%) and other normal-appearing white matter in patients with MS (38.1%).
The MT ratio reveals progressive focal abnormalities in MS that antedate by up to 2 years the appearance of lesions on T2-weighted MR images.
确定多发性硬化症（MS）患者斑块形成前后白质区域磁化传递（MT）的演变情况。
在一项为期5年的纵向评估中，30例MS患者接受了常规磁共振（MR）成像、MT MR成像及临床评估。还收集了12名健康受试者的横断面数据。利用T2加权MR图像进行半自动病变分类，以测量每个体素中MT比率（根据有无MT饱和时采集的MR数据计算）的时间进程，并有助于分析其与T2加权图像上所示病变状态的关系。
在T2加权图像上病变出现后，病变MT比率有显著的（P<.001）时间性下降。在T2加权图像上最初检测到病变之前，后来成为病变的体素中MT比率也有显著的（P<.001）进行性下降。甚至在病变出现前1.5年，注定会成为此类病变的区域中的MT比率（33.3%）就显著（P<.001）低于健康受试者白质中的MT比率（41.3%）以及MS患者其他外观正常的白质中的MT比率（38.1%）。
MT比率揭示了MS中逐渐出现的局灶性异常，其在T2加权MR图像上病变出现前长达2年就已存在。
