Melhem E R, Breiter S N, Ulug A M, Raymond G V, Moser H W
Department of Radiology, Boston University Medical Center, MA 02118, USA.
AJR Am J Roentgenol. 1996 Mar;166(3):689-95. doi: 10.2214/ajr.166.3.8623652.
We performed this study to evaluate the usefulness of magnetization transfer (MT) imaging techniques and magnetization transfer ratio (MTR) measurements in assessing patients with adrenoleukodystrophy (ALD).
Twelve patients who encompassed the range of ALD phenotypes were evaluated prospectively with MR and MT imaging (including digital subtraction images). The MT images and spin-echo MR images were compared by two staff neuroradiologists and a staff neurologist for extent of disease, different zones of involvement, and the presence of enhancement. MTR measurements were obtained from affected and unaffected regions of the brain.
Eight of the 12 patients exhibited gadolinium enhancement. In seven of these patients, the MT subtraction images showed two zones of abnormal signal within the affected white matter. Their MTR measurements were classified as zone 1 (mean MTR, 35%; SD, 6%) and zone 2 (mean MTR, 20%; SD, 6%). Three of the other patients showed a single zone of involvement corresponding to the affected white matter on the standard spin-echo MR images. Their MTR measurements were similar to that of zone 1. The remaining two patients had no demonstrable signal abnormalities on any of the images. We noted no difference in any of the 12 subjects in the extent of white matter involvement on any of the imaging techniques. The MTR measurements in the unaffected white matter (mean MTR, 46%; SD, 5%) approximated established MTRs in white matter of normal volunteers.
MT imaging and MTR measurements are helpful clinical techniques that may improve the evaluation of patients with ALD, particularly in the proposed ability of these techniques to divide the affected white matter into different zones that correspond to specific pathologic areas. These techniques can help the understanding of pathogenetic mechanisms and the evaluation of therapies.
我们开展这项研究以评估磁化传递（MT）成像技术及磁化传递率（MTR）测量在肾上腺脑白质营养不良（ALD）患者评估中的作用。
前瞻性地对12例涵盖ALD各种表型的患者进行磁共振成像（MR）及MT成像（包括数字减影图像）评估。两名神经放射科工作人员和一名神经科工作人员对MT图像和自旋回波MR图像进行比较，观察疾病范围、不同受累区域及强化情况。从大脑的受累及未受累区域获取MTR测量值。
12例患者中有8例出现钆强化。其中7例患者的MT减影图像显示受累白质内有两个异常信号区。其MTR测量值分为1区（平均MTR，35%；标准差，6%）和2区（平均MTR，20%；标准差，6%）。另外3例患者在标准自旋回波MR图像上显示对应受累白质的单个受累区域。其MTR测量值与1区相似。其余2例患者在任何图像上均未显示明显信号异常。我们发现，在12例受试者中，任何一种成像技术所显示的白质受累范围均无差异。未受累白质的MTR测量值（平均MTR，46%；标准差，5%）接近正常志愿者白质既定的MTR值。
MT成像及MTR测量是有助于临床的技术，可能会改善ALD患者的评估，特别是这些技术有可能将受累白质划分为对应特定病理区域的不同区域。这些技术有助于理解发病机制及评估治疗效果。
