Heart and Stroke Foundation Centre for Stroke Recovery, Toronto, ON, Canada.
Eur J Neurol. 2013 Feb;20(2):243-50. doi: 10.1111/j.1468-1331.2012.03785.x. Epub 2012 Jun 28.
White matter hyperintensities (WMH) are associated with aging and are prevalent in various brain pathologies. The purpose of the current study was to characterize WMH perfusion in age-matched elderly controls (ECs) and patients with Alzheimer's disease (ADs).
Fifty ECs (23 men) and 61 ADs (33 men) underwent magnetic resonance imaging (MRI), 99mTc-ECD single-photon emission computed tomography (SPECT) and cognitive testing. Brain tissue type was classified on T1 weighted images, and WMH were identified on interleaved proton density/T2 weighted images. Co-registered MR images were used to characterize SPECT perfusion patterns.
WMH perfusion was lower than normal appearing white matter (NAWM) perfusion (P < 0.001) in both EC and AD groups. There was no WMH perfusion difference between groups when considering the mean perfusion from all WMH voxels (P > 0.43). However, locations that were likely to be considered WMH tended to have lower perfusion in ADs compared with ECs. Perfusion gradients along watershed white matter regions were significantly different between EC and AD groups (P < 0.05). A relationship was found between the volume of a WMH lesion and its mean perfusion (P < 0.001) in both ECs and ADs.
Global WMH were hypoperfused compared with NAWM to the same degree in EC and AD participants, which suggests a common WMH etiology between groups. However, white matter locations that were likely to contain WMH tended to be hypoperfused in ADs compared with healthy aging. This finding is suggestive of AD-specific pathology that reduces the perfusion at anatomic locations susceptible to the formation of WMH through either the neurodegenerative process or AD-related vasculopathy or both.
脑白质高信号（WMH）与衰老有关，并且在各种脑部病变中普遍存在。本研究的目的是描述年龄匹配的老年对照组（EC）和阿尔茨海默病（AD）患者的 WMH 灌注情况。
50 名 EC（23 名男性）和 61 名 AD（33 名男性）接受了磁共振成像（MRI）、99mTc-ECD 单光子发射计算机断层扫描（SPECT）和认知测试。在 T1 加权图像上对脑组织类型进行分类，并在交错质子密度/T2 加权图像上识别 WMH。对配准的 MR 图像进行分析以描述 SPECT 灌注模式。
WMH 的灌注低于正常外观的白质（NAWM）灌注（P<0.001），在 EC 和 AD 组中均如此。当考虑所有 WMH 体素的平均灌注时，两组之间没有 WMH 灌注差异（P>0.43）。然而，在 AD 中，那些可能被认为是 WMH 的部位的灌注值比 EC 中低。在 EC 和 AD 组之间，沿着分水岭白质区域的灌注梯度有显著差异（P<0.05）。在 EC 和 AD 中，WMH 病变的体积与其平均灌注之间存在相关性（P<0.001）。
与 EC 和 AD 参与者的 NAWM 相比，全局 WMH 的灌注均较低，这表明两组之间存在共同的 WMH 病因。然而，在 AD 中，那些可能包含 WMH 的白质部位的灌注值比健康衰老时低。这一发现提示 AD 特有的病理学，通过神经退行性过程或 AD 相关血管病变或两者共同作用，导致 WM 易发生病变的部位的灌注降低。
