Kraut Michael A, Beason-Held Lori L, Elkins Wendy D, Resnick Susan M
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
J Cereb Blood Flow Metab. 2008 Jan;28(1):190-7. doi: 10.1038/sj.jcbfm.9600512. Epub 2007 May 30.
White matter hyperintensities are frequently detected on cranial magnetic resonance imaging (MRI) scans of older adults. Given the presumed ischemic contribution to the etiology of these lesions and the posited import of resting brain activity on cognitive function, we hypothesized that longitudinal changes in MRI-detected white matter disease, and its severity at a given time point, would be associated with changes in regional cerebral blood flow (rCBF) over time. We evaluated MRI scans and resting H(2)(15)O positron emission tomographic rCBF at baseline and after an average of 7.7-year follow-up in Baltimore Longitudinal Study of Aging participants without dementia. Differences in patterns of rCBF were evident at baseline and at follow-up between the group of subjects showing increased white matter disease over the 8-year interval compared with the group with stable white matter ratings. Furthermore, longitudinal changes over time in rCBF also differed between the two groups. Specifically, the group with progressive white matter abnormalities showed greater increase in the right inferior temporal gyrus/fusiform gyrus, right anterior cingulate, and the rostral aspect of the left superior temporal gyrus. Regions of greater longitudinal decrease in this group were evident in the right inferior parietal lobule and at the right occipital pole. Changes in white matter disease over time and its severity at any given time are associated significantly with both cross-sectional and longitudinal patterns of rCBF. The longitudinal increases may reflect cortical compensation mechanisms for reduced efficacy of interregional neural communications that result from white matter deterioration.
在老年人的头颅磁共振成像（MRI）扫描中经常检测到白质高信号。鉴于这些病变的病因推测与缺血有关，且静息脑活动对认知功能有重要作用，我们假设MRI检测到的白质病变的纵向变化及其在给定时间点的严重程度与区域脑血流量（rCBF）随时间的变化有关。我们在巴尔的摩纵向衰老研究中对无痴呆的参与者进行了基线和平均7.7年随访后的MRI扫描以及静息状态下的H₂¹⁵O正电子发射断层扫描rCBF评估。在8年期间白质病变增加的受试者组与白质评级稳定的组相比，基线和随访时rCBF模式的差异明显。此外，两组之间rCBF随时间的纵向变化也不同。具体而言，白质进行性异常的组在右侧颞下回/梭状回、右侧前扣带回和左侧颞上回的喙侧部分有更大的增加。该组中纵向下降更大的区域在右侧顶下小叶和右侧枕极明显。白质病变随时间的变化及其在任何给定时间的严重程度与rCBF的横断面和纵向模式均显著相关。纵向增加可能反映了由于白质退化导致区域间神经通讯效率降低的皮质补偿机制。
