Eichler Florian S, Itoh Ryuta, Barker Peter B, Mori Susumu, Garrett Elizabeth S, van Zijl Peter C M, Moser Hugo W, Raymond Gerald V, Melhem Elias R
F. M. Kirby Research Center for Functional Brain Imaging, Johns Hopkins University, Baltimore, MD, USA.
Radiology. 2002 Oct;225(1):245-52. doi: 10.1148/radiol.2251011040.
To compare conventional magnetic resonance (MR) imaging, proton MR spectroscopic imaging, and diffusion tensor (DT) MR imaging findings in patients with X chromosome-linked adrenoleukodystrophy (X-ALD).
Multisection proton MR spectroscopy and DT imaging were performed in 11 patients with X-ALD and in 11 healthy control subjects. Quantitative measures of N-acetylaspartate (NAA), choline, and creatine values and of isotropic apparent diffusion coefficient (IADC) and fractional anisotropy (FA) were obtained from coregistered regions of interest. DT imaging and metabolic parameters were compared by using regression analysis. In addition, differences in DT imaging and metabolite measurements between normal- and abnormal-appearing white matter on conventional MR images were evaluated by using a nonparametric (Mann-Whitney) test.
A strong logarithmic relationship between NAA value and FA (r = 0.64, P <.001) and an inverse logarithmic relationship were found between NAA value and IADC (r = -0.69, P <.001). Creatine and choline values correlated poorly with IADC and FA. In the normal-appearing white matter of asymptomatic patients, the NAA value was 17% lower than that in the healthy control subjects (P =.016), whereas no significant difference in DT imaging measures was seen in these regions.
In patients with X-ALD, MR spectroscopic imaging can depict abnormalities in white matter that have a normal appearance on both conventional MR and DT images; this finding suggests that it may be the most sensitive technique for detecting early abnormalities of demyelination or axonal loss in patients with X-ALD.
比较X染色体连锁肾上腺脑白质营养不良（X-ALD）患者的传统磁共振（MR）成像、质子MR波谱成像和扩散张量（DT）MR成像结果。
对11例X-ALD患者和11名健康对照者进行多层面质子MR波谱分析和DT成像。从配准的感兴趣区域获取N-乙酰天门冬氨酸（NAA）、胆碱和肌酸值以及各向同性表观扩散系数（IADC）和分数各向异性（FA）的定量测量值。采用回归分析比较DT成像和代谢参数。此外，使用非参数（曼-惠特尼）检验评估传统MR图像上正常和异常白质之间DT成像和代谢物测量的差异。
发现NAA值与FA之间存在强对数关系（r = 0.64，P <.001），NAA值与IADC之间存在负对数关系（r = -0.69，P <.001）。肌酸和胆碱值与IADC和FA的相关性较差。在无症状患者的正常白质中，NAA值比健康对照者低17%（P =.016），而在这些区域的DT成像测量中未见显著差异。
在X-ALD患者中，MR波谱成像可以描绘出在传统MR和DT图像上外观正常的白质异常；这一发现表明，它可能是检测X-ALD患者早期脱髓鞘或轴突丢失异常的最敏感技术。
