90%。1H-MRS MI检测对AD早期诊断具有非常重要的意义。Waldman[4]对大脑皮质进行研究发现,AD患者枕叶MI/Cr明显高于VD患者,且AD组MI/NAA与MMSE具相关性,而VaD不存在此相关性。同时发现,两组患者NAA/Cr和Cho/Cr的降低没有明显差别。MI异常对VD诊断价值目前结论不一,进一步研究有助于揭示其具体的意义。 3.2 1H-MRS与痴呆的临床病程 随着时间的进展,痴呆患者病变范围不断扩大,患者认知、记忆能力逐渐下降。1H-MRS可通过化合物浓度变化来反应痴呆的病理改变,1H-MRS对NAA/Cr,NAA/MI,MI/Cr及这三种化合物浓度绝对值得测量具有较高的可重复性和稳定性[16]。AD患者MMSE评分与右半球脑皮质NAA/Cr呈明显正相关,可反映痴呆的严重程度[1,12]。Rose等[16]对AD患者研究显示NAA/MI与MMSE之间存在正相关,而MI/Cr和MMSE之间呈负相关。一些代谢物与相应体素萎缩间的相关性也达到显著性水平。最近,Kantarci等[21]探讨了轻度认知功能障碍、AD患者1H-MRS与认知指标(痴呆分级和听说测试成绩)间可能存在的联系,发现NAA/MI的回归分析效果最好。另一项研究发现AD患者MMSE评分和扣带回后部NAA/MI(主要是NAA/Cr的成分,MI/Cr的作用要小)存在密切联系,但是这一现象未见于血管性痴呆患者[22]。SIVD以皮质下白质损害为主,皮质下白质的NAA/Cr和NAA/Cho比值与AD患者相比明显减低[13],皮质下白质的1H-MRS研究有望发现与MMSE评分的关系,寻求临床检测VD病程进展的客观指标。并且不同部位NAA的变化与MMSE评分的关系可在一定程度上鉴别诊断VD与AD。 3.3 1H-MRS对痴呆疗效的观察 NAA反映神经元的功能状态,1H-MRS检查结果可靠,可重复性高,故NAA的检测可用于药物疗效的监测[23]。AD患者和VD患者都存在胆碱能系统的损害,黄延焱[24]给予卒中性VD患者胆碱酯酶抑制剂治疗后,NAA/Cr升高,Cho/Cr降低,MMSE评分也有增高的趋势,与Cho/Cr存在负相关性。随着痴呆的临床研究的深入,对痴呆的认识也在不断加深,出现了一些新疗法。对于疗效的监测,结构影像学很难发现明显的改变,1H-MRS对检测生物化学方面改变的监测,具有很大的意义。 综上所述,1H-MRS能够从细胞功能代谢的角度对痴呆进行深入的研究,明确病理变化过程,鉴别痴呆的类型,监控疾病的发展演变,但是目前的研究结论尚未获得病理及病理生理的证实,检查方法本身较为复杂,尚未应用到临床实践中。随着研究的深入,1H-MRS比较成为痴呆重要的影像学检查手段,提高痴呆类型诊断的准确度,监测疾病的发展过程。 【参考文献】 1 丁萍,嵇鸣,苗华栋,等.Alzheimer病和血管性痴呆的磁共振波谱分析.上海医学影像杂志,2004,13(2):91-93. 2 Geldmacher D,Whitehouse P.Evaluation of dementia.The New England Journal of Medicine,1996,335:330-336. 3 Erkinjuntti T,Inzitari D,Pantoni L,et al.Limitations of clinical criteria for the diagnosis of vascular dementia in clinical trials.Is a focus on subcortical vascular dementia a solution? ANN N Y Acad SCI,2000,903:263-272. 4 Waldman AD,Rai GS,McConnell JR,et al.Clinical brain proton magnetic resonance spectroscopy for management of Alzheimer’s and sub-cortical ischemic vascular dementia in older people.Arch Gerontol Geriatr,2002,35(2):137-142. 5 Prlzrkall A,Nelson SJ,Mcknight TR,et al.Metabobic imagin of lowgrade gliomas with threeHmensional magnetic resonance spectroscopy.Int J Radiat oncol Biolphys,2002,53(5):1254-1264. 6 Bates T,Strandward M,Keelan J,et al.Inhibition of N-acetylaspartate production:Implications for 1H MRS studies in vivo.Neuroreport,1995,7:1397-1400. 7 Krishnan KR,Charles HC,Doraiswamy PM, et al.Randomized,placebo-controlled trial of the effects of donepezil on neuronal markers and hippocampal volumes in Alzheimer’s disease.Am J Psychiatry,2003,160:2003-2011. 8 Kantarci K,Reynolds G,Petersen RC,et al.Proton MR spectroscopy in mild cognitive impairment and Alzheimer’s disease:comparison of 1.5T and 3T.AJNR,2003,24(5):843-849. 9 Meyerhoff DJ,DR Rer N,Mackay S,et al.Axonal injury and membrane alterations in Alzheimer’s disease suggested by in vivo proton magnetic resonance spectroscopic imaging.Ann Neurol,1994,36(1):40-47. 10 Catani M,Macocci P,Tarducci R,et al.Proton magnetic resonance spectroscopy reveals similar white matter biochemical changes in patients with chronic hypertension and early Alzheimer’s disease.J Am Geriatr Soc,2002,50(10):1707-1710. 11 Schuff N,Capizzano AA,Du AT, et al.Selective reduction of N-acetylaspartate in medial temporal and parietal lobes in AD.Neurology,2002,58:928-935. 12 MacKay S,Ezekiel F,Di Sclafani V,et al.Alzheimer’s disease and subcortical ischemic vascular dementia:Evaluation by combining MR imaging segmentation and H-1 MR spectroscopic imaging.Radiology,1996,198:537-545. 13 Kattapong VJ,Brooks WM,Wesley MH,et al.Proton magnetic resonance spectroscopy of vascular-and Alzheimer-type dementia.Arch Neurol,1996,53:678-680. 14 Strange K,Emma F,Paredes A, et al.Osmoregulatory changes in myo-inositol content and Na+/myo-inositol cotransport in rat cortical astrocytes.Glia,1994,12:35-43. 15 Kantarci K,Jack CR,Xu Y,et al.Regional metabolic patterns in mild cognitive impairment and alzheimer’s disease:A 1H-MRS study.Neurology,2000,55(2):210-217. 16 Rose SE,De Zubicaray GI,Wang D, et al.A 1H-MRS study of probable Alzheimer’s disease and normal aging:Implications for longitudinal monitoring of dementia progression.Magn Reson Imaging,1999,17:291-299. 17 Herminghaus S,Frolich L,Gorriz C,et al.Brain metabolism in Alzheimer disease and vascular dementia assessed by in vivo proton magnetic resonance spectroscopy.Psychiatr Res:Neuroimaging,2003,123:183-849. 18 Constans JM,Meyerhoff DJ,Gerson J,et al.H-1 MR spectroscopic imaging of white matter signal hyperintensities:Alzheimer disease and ischemic vascular dementia.Radiology,1995,197:517-523. 19 Salem DB,Walker PM,Osseby GV,et al.Subcortical gray matter N-acetylaspartate reduction in two cases of vascular dementia.J.Clin Imag,2003,27:14-17. 20 Shonk TK,Moats RA,Gifford P,et al.Probable Alzheimer disease:diagnosis with proton MR spectroscopy.Radiology,1995,195:65-72. 21 Kantarci K,Smith GE,Ivnik RJ,et al.1H magnetic resonance spectroscopy,cognitive function,and apolipoprotein E genotype in normal aging,mild cognitive impairment and Alzheimer’s disease.J Int Neuropsychol Soc,2002,8:934-942. 22 Waldman AD,Rai GS.The relationship between cognitive impairment and 上一页 [1] [2] [3] 下一页
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