N-乙酰天冬氨酸(N-acetylaspartate,NAA)是一种在大脑中大量存在的代谢物。NAA作为一种反映神经系统功能情况的重要标志物,广泛应用于核磁共振波谱(proton magnetic resonance spectroscopy,1H MRS)技术对脑内代谢产物的分析中。NAA在...N-乙酰天冬氨酸(N-acetylaspartate,NAA)是一种在大脑中大量存在的代谢物。NAA作为一种反映神经系统功能情况的重要标志物,广泛应用于核磁共振波谱(proton magnetic resonance spectroscopy,1H MRS)技术对脑内代谢产物的分析中。NAA在神经元内的线粒体内合成,进入少突胶质细胞内代谢,或在神经元内合成N-乙酰天冬氨酰谷氨酸(N-acetylaspartylglutamate,NAAG),经星形胶质细胞摄取分解。研究发现,NAA与多种中枢神经系统疾病相关,包括Canavan疾病、多发性硬化以及抑郁症、精神分裂症等精神疾病,因此,NAA可能作为这些疾病的生物标志物,其相关酶可能作为治疗靶点进行药物筛选。本文将从NAA分子机制研究入手,介绍NAA在脑内的生成、代谢与转运过程,阐述其可能发挥的生理作用,并对NAA在中枢神经系统疾病中的相关研究进展进行综述,探讨NAA在疾病的预测、诊断方面的前景,以及可能成为难治性疾病突破口的靶向治疗方式。展开更多
目的评价磁共振多体素波谱扫描技术对颞叶癫痫的定位诊断价值。方法选择具有明显颞叶癫痫表现,并经脑电图检查定位诊断明确的单侧颞叶癫痫患者30例作为研究对象;排除M R I检查存在颅脑肿瘤、脑血管畸形等症状性癫痫患者。患者均行常规M...目的评价磁共振多体素波谱扫描技术对颞叶癫痫的定位诊断价值。方法选择具有明显颞叶癫痫表现,并经脑电图检查定位诊断明确的单侧颞叶癫痫患者30例作为研究对象;排除M R I检查存在颅脑肿瘤、脑血管畸形等症状性癫痫患者。患者均行常规M RI及双侧海马区多体素波谱扫描,完成检查后将以代谢物峰值含量为灰阶的伪彩图与倾斜冠状重度T2W I图像进行融合,测量双侧海马区N-乙酰天冬氨酸、胆碱峰值含量和胆碱/N-酰天冬氨酸比值,并直观分析双侧海马区两代谢物的分布情乙况。结果患侧N-乙酰天冬氨酸峰值含量为(13587.61±3913.99)M R units,健侧为(17683.10±5610.61)M R units,患侧低于健侧差异有显著性意义(t=6.728,P<0.001);患侧胆碱/N-乙酰天冬氨酸比值为(1.26±0.11),健侧比值为(1.01±0.14),患侧高于健侧差异亦有显著性意义(t=7.883,P<0.001)。将两代谢物含量及比值伪彩图与常规M RI图像进行融合,可直观发现双侧海马区N-乙酰天冬氨酸峰值含量及胆碱/N-酰天冬氨酸比值存在明显差异。结论磁共振多体素波谱技术不仅可以通过对某些代谢物含量乙的定量分析进行癫痫灶的定位、定侧诊断,还可通过常规M RI图像与多体素磁共振波谱图像的融合图像直观评价代谢物分布状态,描记癫痫灶的大致轮廓,为制定手术方案提供依据。展开更多
Our objective was to investigate axonal dysfunction in patients with systemic lupus erythematosus (SLE) using proton magnetic resonance spectroscopy (1H-MRS)-We studied prospectively 90 SLE patients (mean age of 32.5 ...Our objective was to investigate axonal dysfunction in patients with systemic lupus erythematosus (SLE) using proton magnetic resonance spectroscopy (1H-MRS)-We studied prospectively 90 SLE patients (mean age of 32.5 years) and 23 normal volunteers (mean age of 33.8 years). We performed single voxel proton MRS using point resolved spectroscopy sequence over the superior-posterior region of the corpus callosum. We measured signals from N-acetyl compounds N-acetylaspartate (NAA) at 2.01 p.p.m., choline-based compounds (Cho) at 3.2 p.p.m. and creatine and phosphocreatine containing compounds (Cr) at 3.0 p.p.m. and determined NAA/Cr ratios. After 12 months, MRI and MRS were repeated in 50 patients and 9 volunteers. Patients were divided according to disease activity (measured by SLE disease activity index)during initial and follow-up MRS. We performed paired t-test and ANOVA with Tukey’s post hoc comparisons to evaluate group differences. At study entry, 29 patients had active SLE with involvement of central nervous system (CNS) and 28 patients had active SLE without CNS manifestations. A total of 14 patients had inactive SLE with past CNS presentation, and 19 had inactive SLE without history of CNS involvement. NAA/Cr ratios were significant lower in patients with active SLE, independently of CNS involvement, when compared with patients with inactive SLE (P = 0.005) and controls (P = 0.01). We observed a significant increase in NAA/Cr ratio in 15 patients who had active SLE at initial MRS and inactive SLE at follow-up (P = 0.04). In 10 patients with active SLE both at initial and at follow-up MRS we observed a reduction in NAA/Cr ratio (P = 0.02). By contrast, there was a significant reduction of NAA/Cr ratio in 15 patients who had inactive SLE at initial MRS and active SLE at follow-up (P = 0.001). In 10 patients with inactive SLE both at initial and at follow-up MRS NAA/Cr ratio did not change (P = 0.2). This study shows evidence of axonal dysfunction in patients with active SLE, independently of CNS manifestations that may be reversible, at least in part, d uring periods of inactivity of disease.展开更多
Developmental delay (DD) in children is a common socioeconomic problem with a prevalence of 1-2%. The cause of DD in children is often unknown, and magnetic resonance imaging plays an important role in evaluating chil...Developmental delay (DD) in children is a common socioeconomic problem with a prevalence of 1-2%. The cause of DD in children is often unknown, and magnetic resonance imaging plays an important role in evaluating children with DD, estimating long-term prognosis, and guiding therapeutic options. The aim of our study on children with DD was to elucidate 1) whether magnetic resonance spectroscopy (MRS) reveals abnormalities in cerebral metabolism and 2) whether there is a correlation between the cognitive performance and the concentration of brain metabolites, especially N-acetylaspartate (NAA), named in the literature a neuronalmarker. Using proton MRS of deep gray and central white matter, we measured concentrations of brain metabolites in 48 children, who were aged 1 mo to 13 y and had unexplained DD [develo- pmental quotient (DQ) between < 50 and 85] and normal magnetic resonance imaging examinations, and compared them with those of 23 age-matched normal control children. Children with DD were divided into three groups: mild (DQ 76-85),moderate (DQ 51-75), and severe (DQ < 50). We found no significant differences in metabolite concentrations, neither among the three groups of children with DD nor between patients and age-matched normal control children. Independent of the degree of mental retardation, the NAA concentrations of handicapped patients and normal children were comparable. We conclude that 1) brain metabolites, especially NAA, in children with unexplained DD are within normal limits, and 2) in most cases, proton MRS adds little information concerning cause of unexplained DD.展开更多
文摘N-乙酰天冬氨酸(N-acetylaspartate,NAA)是一种在大脑中大量存在的代谢物。NAA作为一种反映神经系统功能情况的重要标志物,广泛应用于核磁共振波谱(proton magnetic resonance spectroscopy,1H MRS)技术对脑内代谢产物的分析中。NAA在神经元内的线粒体内合成,进入少突胶质细胞内代谢,或在神经元内合成N-乙酰天冬氨酰谷氨酸(N-acetylaspartylglutamate,NAAG),经星形胶质细胞摄取分解。研究发现,NAA与多种中枢神经系统疾病相关,包括Canavan疾病、多发性硬化以及抑郁症、精神分裂症等精神疾病,因此,NAA可能作为这些疾病的生物标志物,其相关酶可能作为治疗靶点进行药物筛选。本文将从NAA分子机制研究入手,介绍NAA在脑内的生成、代谢与转运过程,阐述其可能发挥的生理作用,并对NAA在中枢神经系统疾病中的相关研究进展进行综述,探讨NAA在疾病的预测、诊断方面的前景,以及可能成为难治性疾病突破口的靶向治疗方式。
文摘目的评价磁共振多体素波谱扫描技术对颞叶癫痫的定位诊断价值。方法选择具有明显颞叶癫痫表现,并经脑电图检查定位诊断明确的单侧颞叶癫痫患者30例作为研究对象;排除M R I检查存在颅脑肿瘤、脑血管畸形等症状性癫痫患者。患者均行常规M RI及双侧海马区多体素波谱扫描,完成检查后将以代谢物峰值含量为灰阶的伪彩图与倾斜冠状重度T2W I图像进行融合,测量双侧海马区N-乙酰天冬氨酸、胆碱峰值含量和胆碱/N-酰天冬氨酸比值,并直观分析双侧海马区两代谢物的分布情乙况。结果患侧N-乙酰天冬氨酸峰值含量为(13587.61±3913.99)M R units,健侧为(17683.10±5610.61)M R units,患侧低于健侧差异有显著性意义(t=6.728,P<0.001);患侧胆碱/N-乙酰天冬氨酸比值为(1.26±0.11),健侧比值为(1.01±0.14),患侧高于健侧差异亦有显著性意义(t=7.883,P<0.001)。将两代谢物含量及比值伪彩图与常规M RI图像进行融合,可直观发现双侧海马区N-乙酰天冬氨酸峰值含量及胆碱/N-酰天冬氨酸比值存在明显差异。结论磁共振多体素波谱技术不仅可以通过对某些代谢物含量乙的定量分析进行癫痫灶的定位、定侧诊断,还可通过常规M RI图像与多体素磁共振波谱图像的融合图像直观评价代谢物分布状态,描记癫痫灶的大致轮廓,为制定手术方案提供依据。
文摘Our objective was to investigate axonal dysfunction in patients with systemic lupus erythematosus (SLE) using proton magnetic resonance spectroscopy (1H-MRS)-We studied prospectively 90 SLE patients (mean age of 32.5 years) and 23 normal volunteers (mean age of 33.8 years). We performed single voxel proton MRS using point resolved spectroscopy sequence over the superior-posterior region of the corpus callosum. We measured signals from N-acetyl compounds N-acetylaspartate (NAA) at 2.01 p.p.m., choline-based compounds (Cho) at 3.2 p.p.m. and creatine and phosphocreatine containing compounds (Cr) at 3.0 p.p.m. and determined NAA/Cr ratios. After 12 months, MRI and MRS were repeated in 50 patients and 9 volunteers. Patients were divided according to disease activity (measured by SLE disease activity index)during initial and follow-up MRS. We performed paired t-test and ANOVA with Tukey’s post hoc comparisons to evaluate group differences. At study entry, 29 patients had active SLE with involvement of central nervous system (CNS) and 28 patients had active SLE without CNS manifestations. A total of 14 patients had inactive SLE with past CNS presentation, and 19 had inactive SLE without history of CNS involvement. NAA/Cr ratios were significant lower in patients with active SLE, independently of CNS involvement, when compared with patients with inactive SLE (P = 0.005) and controls (P = 0.01). We observed a significant increase in NAA/Cr ratio in 15 patients who had active SLE at initial MRS and inactive SLE at follow-up (P = 0.04). In 10 patients with active SLE both at initial and at follow-up MRS we observed a reduction in NAA/Cr ratio (P = 0.02). By contrast, there was a significant reduction of NAA/Cr ratio in 15 patients who had inactive SLE at initial MRS and active SLE at follow-up (P = 0.001). In 10 patients with inactive SLE both at initial and at follow-up MRS NAA/Cr ratio did not change (P = 0.2). This study shows evidence of axonal dysfunction in patients with active SLE, independently of CNS manifestations that may be reversible, at least in part, d uring periods of inactivity of disease.
文摘Developmental delay (DD) in children is a common socioeconomic problem with a prevalence of 1-2%. The cause of DD in children is often unknown, and magnetic resonance imaging plays an important role in evaluating children with DD, estimating long-term prognosis, and guiding therapeutic options. The aim of our study on children with DD was to elucidate 1) whether magnetic resonance spectroscopy (MRS) reveals abnormalities in cerebral metabolism and 2) whether there is a correlation between the cognitive performance and the concentration of brain metabolites, especially N-acetylaspartate (NAA), named in the literature a neuronalmarker. Using proton MRS of deep gray and central white matter, we measured concentrations of brain metabolites in 48 children, who were aged 1 mo to 13 y and had unexplained DD [develo- pmental quotient (DQ) between < 50 and 85] and normal magnetic resonance imaging examinations, and compared them with those of 23 age-matched normal control children. Children with DD were divided into three groups: mild (DQ 76-85),moderate (DQ 51-75), and severe (DQ < 50). We found no significant differences in metabolite concentrations, neither among the three groups of children with DD nor between patients and age-matched normal control children. Independent of the degree of mental retardation, the NAA concentrations of handicapped patients and normal children were comparable. We conclude that 1) brain metabolites, especially NAA, in children with unexplained DD are within normal limits, and 2) in most cases, proton MRS adds little information concerning cause of unexplained DD.
