Maier-Hein Klaus H, Westin Carl-Fredrik, Shenton Martha E, Weiner Michael W, Raj Ashish, Thomann Philipp, Kikinis Ron, Stieltjes Bram, Pasternak Ofer
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Junior Group Medical Image Computing, German Cancer Research Center, Heidelberg, Germany; Junior Group Quantitative Image-based Disease Characterization, German Cancer Research Center, Heidelberg, Germany.
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Alzheimers Dement. 2015 May;11(5):485-493.e2. doi: 10.1016/j.jalz.2014.04.518. Epub 2014 Jul 14.
Brain atrophy in subjects with mild cognitive impairment (MCI) introduces partial volume effects, limiting the sensitivity of diffusion tensor imaging to white matter microstructural degeneration. Appropriate correction isolates microstructural effects in MCI that might be precursors of Alzheimer's disease (AD).
Forty-eight participants (18 MCI, 15 AD, and 15 healthy controls) had magnetic resonance imaging scans and clinical evaluations at baseline and follow-up after 36 months. Ten MCI subjects were diagnosed with AD at follow-up and eight remained MCI. Free-water (FW) corrected measures on the white matter skeleton were compared between groups.
FW corrected radial diffusivity, but not uncorrected radial diffusivity, was increased across the brain of the converted group compared with the nonconverted group (P < .05). The extent of increases was similar to that found comparing AD with controls.
Partial volume elimination reveals microstructural alterations preceding dementia. These alterations may prove to be an effective and feasible early biomarker of AD.
轻度认知障碍（MCI）患者的脑萎缩会产生部分容积效应，限制了扩散张量成像对白质微观结构退变的敏感性。适当的校正可分离出MCI中可能是阿尔茨海默病（AD）先兆的微观结构效应。
48名参与者（18名MCI患者、15名AD患者和15名健康对照者）在基线时以及36个月后的随访时进行了磁共振成像扫描和临床评估。10名MCI受试者在随访时被诊断为AD，8名仍为MCI。比较了各组在白质骨架上的自由水（FW）校正测量值。
与未转化组相比，转化组全脑的FW校正径向扩散率增加，而未校正的径向扩散率未增加（P < 0.05）。增加程度与AD患者和对照者比较时发现的相似。
部分容积消除揭示了痴呆之前的微观结构改变。这些改变可能被证明是AD一种有效且可行的早期生物标志物。
