van der Knaap M S, Naidu S, Breiter S N, Blaser S, Stroink H, Springer S, Begeer J C, van Coster R, Barth P G, Thomas N H, Valk J, Powers J M
Department of Child Neurology, Free University Hospital, Amsterdam, the Netherlands.
AJNR Am J Neuroradiol. 2001 Mar;22(3):541-52.
To date, the demonstration of Rosenthal fibers on brain biopsy or autopsy specimens is considered a prerequisite for a definitive diagnosis of Alexander disease. We initiated a multiinstitutional survey of MR abnormalities in both presumed and confirmed cases of Alexander disease to assess the possibility of an MR-based diagnosis.
MR imaging studies in three patients with an autopsy-based diagnosis of Alexander disease were analyzed to define MR criteria for the diagnosis. These criteria were then applied to 217 children with leukoencephalopathy of unknown origin.
Five MR imaging criteria were defined: extensive cerebral white matter changes with frontal predominance, a periventricular rim with high signal on T1-weighted images and low signal on T2-weighted images, abnormalities of basal ganglia and thalami, brain stem abnormalities, and contrast enhancement of particular gray and white matter structures. Four of the five criteria had to be met for an MR imaging-based diagnosis. In a retrospective analysis of the MR studies of the 217 patients, 19 were found who fulfilled these criteria. No other essentially new MR abnormalities were found in these patients. In four of the 19 patients, subsequent histologic confirmation was obtained. The clinical symptomatology was the same in the patients with and without histologic confirmation and correlated well with the MR abnormalities. MR abnormalities were in close agreement with the known histopathologic findings of Alexander disease.
The defined criteria are sufficient for an in vivo MR imaging diagnosis of Alexander disease; only in atypical cases is a brain biopsy still necessary for a definitive diagnosis.
迄今为止，在脑活检或尸检标本上发现罗森塔尔纤维被认为是明确诊断亚历山大病的先决条件。我们发起了一项针对亚历山大病疑似病例和确诊病例的多机构磁共振（MR）异常情况调查，以评估基于MR进行诊断的可能性。
对3例经尸检确诊为亚历山大病的患者的MR成像研究进行分析，以确定诊断的MR标准。然后将这些标准应用于217例不明原因的白质脑病患儿。
定义了5条MR成像标准：广泛的脑白质改变且以额叶为主、T1加权像上脑室周围边缘呈高信号而T2加权像上呈低信号、基底节和丘脑异常、脑干异常以及特定灰质和白质结构的对比增强。基于MR成像的诊断必须满足这5条标准中的4条。在对这217例患者的MR研究进行回顾性分析时，发现有19例符合这些标准。在这些患者中未发现其他本质上新的MR异常。在这19例患者中有4例随后获得了组织学证实。有组织学证实和无组织学证实的患者临床症状相同，且与MR异常密切相关。MR异常与亚历山大病已知的组织病理学发现高度一致。
所定义的标准足以对亚历山大病进行活体MR成像诊断；只有在非典型病例中，仍需要进行脑活检以明确诊断。
