慢性精神分裂症患者双侧海马质子磁共振波谱成像研究

目的 利用质子磁共振波谱(~1H-MRS)研究慢性精神分裂症患者双侧海马生化物质的变化.方法 选择武警广东总队医院神经外科自2007年1月至2009年6月收治的慢性精神分裂症患者25例做为患者组,门诊体检正常志愿者25例为对照组,利用~1H-MRS测量2组成员双侧海马N-乙酰天门冬氨酸(NAA),胆碱复合物(Cho)和肌酸--磷酸肌酸复合物(Cr)含量,计算NAA/Cr和Cho/Cr的比值.结果 慢性精神分裂症患者双侧海马NAA/Cr的比值(左侧2.05±0.14,右侧1.98±0.17)低于正常对照组(左侧2.19±0.13,右侧2.17±0.14),差异有统计学意义(P<0.05);Cho/Cr比值(左侧1.30±0.12,右侧1.25±0.18)高于正常对照组(左侧1.04±0.15,右侧0.95±0.13),差异有统计学意义(P<0.05).结论 慢性精神分裂症患者双侧海马可能存在神经元的缺失或功能损伤,并且伴有膜磷脂代谢紊乱.     

老年期抑郁症患者海马磁共振质子波谱研究

目的:探讨老年期抑郁症患者海马的磁共振质子波谱(1H-MRS)特点。方法:应用1H-MRS成像技术检测11例晚发性抑郁症患者(患者组)予文拉法辛缓释剂治疗6周前后两侧海马头、体、尾部N-乙酰天门冬氨酸(NAA)、胆碱(Cho)和肌酸(Cr)3种代谢物,计算NAA/Cr和Cho/Cr比值。并且与15名健康对照者(对照组)的检测结果进行比较。结果:治疗前后患者组右侧海马头部NAA和Cho含量及左侧海马头部Cho含量均显著低于对照组(P<0.05或P<0.01)。患者组右侧海马头部Cho/Cr治疗前显著低于对照组(P<0.05),治疗后较治疗前显著升高(P<0.05),并且与对照组的差异无显著统计学意义(P>0.05)。患者组右侧海马体部Cho含量治疗前显著低于对照组(P<0.05),治疗后右侧海马体部NAA/Cr和Cho/Cr显著高于治疗前,与对照组的差异无显著统计学意义(P>0.05)。结论:老年期抑郁症患者可能存在左右两侧海马头部细胞膜代谢异常,右侧海马头部神经元活力下降。     

难治性抑郁症患者海马代谢的磁共振质子波谱研究

目的 探讨难治性抑郁症患者双侧海马磁共振质子波谱(1H-MRS)的代谢特点.方法 运用1H-MRS成像系统检测16例难治性抑郁症患者(患者组)和16名健康对照者(对照组)双侧海马的N-乙酰天门冬氨酸(NAA)、胆碱复合物(Cho)、肌醇(mI)及肌酸(Cr)4种代谢产物,分别计算双侧NAA/Cr、Cho/Cr及mI/Cr.采用配对t检验、独立样本t检验及偏相关分析进行统计处理.结果 对照组左侧海马NAA/Cr(1.43±0.19),明显高于右侧(1.21±0.10),P＜0.01.患者组双侧海马NAA/Cr的差异无统计学意义(P＞0.05),右侧海马NAA/Cr(1.44±0.31),明显高于对照组(1.21±0.10),P＜0.01.未发现患者组海马的任何代谢指标与病程及汉密尔顿抑郁量表(17项)评分的相关性(P＞0.05).结论 难治性抑郁症患者右侧海马代谢增强,双侧海马NAA/Cr不对称性消失.     

双相抑郁患者前额叶及海马磁共振质子波谱成像研究

目的探讨双相抑郁患者前额叶及海马磁共振质子波谱(proton magnetic resonance spectroscopy,1H-MRS)的代谢物变化特点,为其神经生物学研究提供线索。方法应用磁共振质子波谱成像技术检测26例双相抑郁患者(患者组)和26例单相抑郁患者及13例健康志愿者(对照组)双侧前额叶白质、前扣带回皮质、海马N-乙酰天门冬氨酸(N-Acetylaspartate,NAA)、胆碱(choline,Cho)、肌酸(creatine,Cr)3种代谢物,以Cr为参照物,分别计算双侧NAA/Cr和Cho/Cr比值。采用SPSS 13.0进行统计处理。结果患者组左侧前额叶白质NAA/Cr(1.65±0.31)低于对照组(2.37±0.36),左侧前额叶白质Cho/Cr(1.35±0.27)低于对照组(1.65±0.21),差异有统计学意义(P<0.05);右侧前额叶白质NAA/Cr、Cho/Cr值与正常对照组差异无统计学意义;患者组双侧前扣带回NAA/Cr、Cho/Cr值与正常对照组差异无统计学意义;患者组双侧海马NAA/Cr、Cho/Cr值与正常对照组差异无统计学意义;患者组与单相抑郁组的双侧额叶白质、双侧前扣带回皮质、双侧海马NAA/Cr、Cho/Cr值差异均无统计学意义。结论双相抑郁患者可能存在左侧前额叶神经元功能下降和膜磷脂代谢异常,其代谢物特点存在偏侧化。     

阳性症状为主型精神分裂症首次发病患者前额叶和海马磁共振质子波谱成像研究

目的 探讨阳性症状为主型精神分裂症首次发病患者前额叶和海马的磁共振质子波谱(1H-MRS)变化特点,为其病因学探讨提供线索.方法 对22例首次发病精神分裂症阳性症状为主型患者(患者组)和11名年龄、性别、受教育时间均匹配的正常对照者(对照组),应用2D 1H-MRS成像技术检测2组双侧前额叶白质、前扣带回皮质、海马N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)3种代谢物,分别计算NAA/Cr和Cho/Cr的比值;采用配对t检验、独立样本t检验进行统计分析.结果 (1)患者组左侧额叶白质NAA/Cr和Cho/Cr分别为(1.63±0.30)和(1.23±0.26),均低于对照组[(2.10±0.30)、(1.54±0.25)],右侧额叶白质NAA/Cr(1.70±0.34)低于对照组(1.97±0.34),差异有统计学意义(P<0.01和P<0.05);(2)双侧前扣带回皮质NAA/Cr、Cho/Cr值与对照组差异无统计学意义(P>0.05);(3)患者组右侧海马NAA/Cr(1.59±0.27)高于对照组(1.24±0.17),差异有统计学意义(P<0.01);(4)对照组内左侧额叶白质Cho/Cr(1.54±0.25)高于右侧(1.35±0.18),左侧海马NAA/Cr(1.45±0.28)高于右侧(1.24±0.17),差异均有统计学意义(P<0.05);(5)患者组内左侧海马NAA/Cr和Cho/Cr分别为(1.43±0.27)和(1.39±0.38),均低于右侧[(1.59±0.27)、(1.56±0.39)],差异有统计学意义(P<0.05).结论 首发精神分裂症阳性症状为主型患者的1H-MRS代谢物与正常人存在差异,提示阳性症状为主型患者存在双侧前额叶白质、海马的神经功能障碍.

Abstract：

Objective To identify the possible alteration of brain functioning in prefrontal lobes and hippocampus in the first-episode positive symptoms of schizophrenia using proton magnetic resonance spectroscopy (1H-MRS). Methods 1H-MRS was performed on prefrontal white matter, anterior cingulated cortex and hippocampus in 22 patients and 11 age-, sex-, and education-matched right-handed healthy controls. The ratios of N-acetylaspartate (NAA)/creatine (Cr) and choline-containing compounds (Cho)/Cr were calculated. Results The NAA/Cr and Cho/Cr ratios in the left prefrontal white matter in patients were lower than that in normal controls (patients, NAA/Cr 1. 63 ±0. 30; Cho/Cr 1. 23 ±0. 26; controls, NAA/Cr 2. 10 ±0. 30; Cho/Cr 1. 54 ± 0. 25, P<0. 01) , and NAA/Cr in the right prefrontal white matter was lower in patients than in controls (patients 1. 70 ± 0. 34; controls 1. 97 ± 0. 34, P<0. 05). There were no significant difference in NAA/Cr, Cho/Cr for the bilateral anterior cingulated cortex between patients and controls (P>0. 05). The ratio of NAA/Cr in the right hippocampus was significantly higher in patients than that in controls (patients 1. 59 ± 0. 27; controls 1. 24 ± 0. 17, P<0. 01). In addition, in healthy controls,Cho/Cr was significantly higher in the left prefrontal white matter than in the right (left 1. 54 ± 0. 25; right 1. 35 ±0. 18, P<0. 05) , and NAA/Cr in the left hippocampus was significantly higher than in the right (left 1. 45 ± 0. 28; right 1. 24 ± 0. 17, P<0. 05). While NAA/Cr and Cho/Cr in the left hippocampus were significantly lower than in the right hippocampus in schizophrenia patients (left, NAA/Cr 1.43 ± 0. 27;Cho/Cr 1.39 ±0.38; right, NAA/Cr 1.59 ±0.27; Cho/Cr 1.56 ±0.39, P<0.05). Conclusion There is the significant difference of manifestation of 1H-MRS between schizophrenia patients with positive symptoms and normal controls, which reflects neuronal dysfunction in the prefrontal lobes and hippocampus.     

路易体痴呆及阿尔茨海默病患者海马氢质子磁共振波谱研究

目的研究路易体痴呆(dementia with Lewy bodies,DLB)及阿尔茨海默病(Alzheimer’s disease,AD)患者双侧海马氢质子磁共振波谱(hydrogen proton magnetic resonance spectroscopy,1H-MRS)代谢物水平变化特点,探索海马1H-MRS在区分DLB和AD中的意义。方法在3T场强条件下,对14例DLB、14例AD患者及15例正常对照(normal control,NC)双侧海马进行单体素1H-MRS采集,测定海马N-乙酰天门冬氨酸(N-acetylaspartate,NAA)、胆碱(choline,Cho)及肌醇(myo-inositol,mI)与肌酸(creatine,Cr)的比值。结果三组海马1H-MRS测量值比较,左、右侧海马NAA/Cr值差异均有统计学意义(F=5.347,P=0.009;F=5.302,P=0.009)。DLB组左侧海马NAA/Cr值(1.56±0.30)、AD组左侧海马NAA/Cr值(1.51±0.22)均低于NC组(1.84±0.35)(均P<0.05)。DLB组右侧海马NAA/Cr值(1.62±0.27)、AD组右侧海马NAA/Cr值(1.49±0.39)均低于NC组(1.90±0.37)(均P<0.05)。DLB组双侧海马NAA/Cr值略高于AD组,但差异无统计学意义(均P>0.05)。三组间双侧海马mI/Cr值、Cho/Cr值差异无统计学意义(均P>0.05)。结论 DLB、AD患者双侧海马存在神经元功能障碍,其代谢物水平不能有效区分DLB和AD。     

精神分裂症患者脑部质子波谱特点及其与临床症状的关系

目的 探讨精神分裂症患者前额叶、丘脑氧质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)的特点及其与临床症状的关系.方法 本研究纳入7 d内未使用抗精神病药物及影响脑内乙酰胆碱神经递质药物的32例精神分裂症患者和36名正常对照,入组24 h内采用多体素1H-MRS检测受试者前额叶和丘脑生化代谢物N-乙酰基天门冬氨酸(NAA)、胆碱复合物(Cho)与肌酸复合物(Cr),并计算NAA/Cr、Cho/Cr和NAA/(Cho+Cr)的比值.患者组同时进行阳性和阴性症状量表(PANSS)评估.结果 患者组左侧前额叶及左右侧丘脑NAA/Cr值[分别为(1.30±0.39)、(1.53±0.36)和(1.47±0.35)]均低于对照组[分别为(1.74±0.24)、(1.73±0.25)和(1.74±0.31)],差异具有统计学意义(P＜0.05);患者组左侧前额叶NAA/(Cho+cr)值[(0.63±0.12)]低于对照组[(0.74±0.21)],差异具有统计学意义(P＜0.05).患者组左侧前额叶NAA/Cr值与PANSS总分及阴性症状分呈负相关(r=-0.48,P＜0.01;r=-0.54,P＜0.01),右侧丘脑NAA/Cr值与阴性症状呈负相关(r=-0.44,P＜0.01).结论 精神分裂症患者前额叶及丘脑存在神经元功能和(或)结构异常,左侧前额叶NAA/Cr值可能作为反映精神分裂症患者阴性症状严重程度的参考指标.     

男性精神分裂症患者海马磁共振质子波谱成像的研究

目的 探讨精神分裂症患者双侧海马的磁共振质子波谱(MRS)的特点,以期对此疾病的临床诊断提供代谢方面依据,为精神分裂症的病因学探讨提供线索。方法 应用MRS成像技术,对20例男性精神分裂症患者和20名男性正常人检测双侧海马的氮-乙酰天门冬氨酸复合物(NAA)、胆碱复合物(CHO)和肌酸-磷酸肌酸复合物(Cr)含量,对NAA/Cr和CHO/Cr的比值进行计算。以重复测量方差分析的方法进行统计分析,其中组别作为组间差异,左右侧作为组内差异。结果 CHO/Cr的比值在精神分裂症患者双侧海马(左侧为1.03±0.22,右侧为1.00±0.23)高于正常人(左侧为0.95±0.16,右侧为0.97±0.16),差异有显著性(F=6.896,P=0.013);而NAA/Cr的比值在精神分裂症患者与正常人间的差异无显著性(患者左侧为1.29±0.16,右侧为1.25±0.13;正常人左侧为1.41±0.20,右侧为1.36±0.17)。结论 男性精神分裂症患者的海马可能存在膜的磷脂代谢异常。     

抑郁症患者前额叶、海马磁共振质子波谱成像的研究

目的探讨抑郁症患者前额叶、海马的磁共振质子波谱(1H-MRS)变化特点。方法应用1H-MRS成像技术检测26例抑郁症患者(抑郁症组)和20名健康对照者(对照组)的前额叶、海马N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)3种代谢物,计算NAA/Cr和Cho/Cr比值。以抑郁症组年龄的中位数(38.5岁)为界将抑郁症组和对照组分为低年龄组[(28±7)岁,14例;(22±6)岁,9名]与高年龄组[(54±9)岁,12例;(53±7)岁,11名]。按病程分为首次发病组(19例,以下简称首发组)和复发组(7例)。采用方差分析进行统计比较。结果高年龄组患者左侧前额叶Cho/Cr(1.60±0.45)×10-6高于对照组(1.28±0.20)×10-6,差异有统计学意义(P<0.05);低年龄组患者右侧前额叶Cho/Cr(1.74±0.51)×10-6高于对照组(1.22±0.40)×10-6,差异有统计学意义(P<0.01)。高年龄组患者左侧海马NAA/Cr(1.16±0.31)×10-6低于对照组(2.21±0.83)×10-6,差异有统计学意义(P<0.01);低年龄组患者左侧海马Cho/Cr(1.54±0.44)×10-6高于对照组(1.08±0.35)×10-6,差异有统计学意义(P<0.05)。首发组患者左侧前额叶Cho/Cr(1.57±0.42)×10-6高于对照组(1.26±0.21)×10-6,复发组患者右侧前额叶Cho/Cr(1.77±0.50)×10-6高于对照组(1.29±0.32)×10-6,差异均有统计学意义(P均<0.01)。首发组患者左侧海马NAA/Cr(1.19±0.26)×10-6及复发组患者左侧海马NAA/Cr(1.10±0.29)×10-6均低于对照组(1.87±0.81)×10-6,复发组患者右侧海马Cho/Cr(2.13±0.51)×10-6高于对照组(1.51±0.52)×10-6,差异均有统计学意义(P均<0.01)。结论抑郁症患者可能存在前额叶、左侧海马细胞膜代谢异常,高年龄抑郁症患者的左侧海马神经元活力下降。     

重复经颅磁刺激对酒依赖患者记忆功能及海马代谢的影响

目的 探讨重复经颅磁刺激(rTMS)对酒依赖患者戒断期记忆功能的影响及与海马代谢物水平变化的关系.方法 将38例男性戒断期酒依赖患者按随机数字表分为rTMS组和伪rTMS组,rTMS组给予1 Hz刺激4周,刺激部位为右侧背外侧前额叶皮质(DLPFC);伪rTMS组给予无效刺激.治疗前后分别评估言语记忆、视觉记忆,并采用氢质子磁共振波谱(1 H-MRS)检测双侧海马部位代谢物N-乙酰基天门冬氨酸(NAA)、胆碱化合物(Cho)和肌酸复合物(Cr).结果 (1)rTMS组治疗后言语记忆和视觉记忆评分较治疗前提高(P<0.05),而伪rTMS组治疗后记忆评分较治疗前差异无统计学意义(P>0.05).治疗后,rTMS组仅视觉记忆评分优于伪rTMS组,差异有统计学意义(P<0.01),而言语记忆未见明显改善(P>0.05).(2)rTMS组治疗后双侧海马NAA/Cr、Cho/Cr较治疗前升高(P<0.01),而伪rTMS组治疗前后双侧海马NAA/Cr、Cho/Cr的差异无统计学意义(P>0.05).治疗后,rTMS组双侧海马NAA/Cr、Cho/Cr高于伪rTMS组,差异有统计学意义(P<0.01).(3)左侧海马NAA/Cr、右侧海马Cho/Cr治疗后与治疗前的差值分别与言语记忆、视觉记忆评分呈正相关(P<0.01).结论 rTMS可以改善戒断期酒依赖患者的记忆功能,其可能机制与升高海马NAA/Cr和Cho/Cr有关.     

抑郁症对海马及背外侧前额叶皮质神经元变与1HMRS表现及明尼苏达多项个性测量的相关性

Background and Purpose The present study was undertaken to elucidate neuro-structural and neuro-chemical characteristics of hippocampi and dorsolateral prefrontal cortex in patients with depressive disorder by using 1H-MRS and to study the association between 1H-MRS and Minnesota Mutiphasic Personality Inventory-2 in relation to the severity of the depression.. Methods Magnetic resonance imaging and 1H-MRS were performed on 33 patients with depressive disorder and age-18 and gender-matched healthy controls. Minnesota Mutiphasic Personality Inventory-2 test was performed on all depressive subjects and control subjects. Results Magnetic resonance imaging and 1H-MRS examinations showed widened sulcus and cisterns as well as the absence of abnormal signal in depressive patients. In addition, the N-acetyl aspartate/total creatine ratios in the bilateral hippocampi and dorsolateral prefrontal cortex were significantly lower in depressive patients than in the control subjects (P<0.01). In contrast, the choline-containing compounds/total creatine ratios in dorsolateral prefrontal cortex were remarkably higher in depressive patients than in the control subjects (Left: P<0.01, Right: P<0.01), the ratios of which were also significantly positively correlated with the depression scores of the patients assessed by Minnesota Mutiphasic Personality Inventory-2 scale (Right: r = 0.8787, Left: r = 0.9347). Conclusions 1H-MRS can be used to reveal reduced neuronal viability or function in the hippocampus and dorsolateral prefrontal cortex and altered membrane phospholipid metabolism in the dorsolateral prefrontal cortex in patients with depressive disorder. The 1H-MRS findings partially reflect the severity of the depressive disorder.     

氟西汀对脑卒中后抑郁患者海马磁共振氢质子波谱影响的研究

目的探讨氟西汀对脑卒中后抑郁患者海马氢质子磁共振波谱(~1 H-MRS)影响的特点。方法以60例脑卒中后抑郁患者为研究组,研究组给予氟西汀抗抑郁治疗8周,以62名脑卒中患者为对照组。采用~1 H-MRS检测脑卒中后抑郁患者(研究组)治疗前后及脑卒中患者(对照组)双侧海马的N-乙酰基天门冬氨酸(NAA)、胆碱复合物(Cho)与肌酸复合物(Cr),以NAA/Cr值和Cho/Cr值进行统计分析。结果研究组治疗前后左右侧海马NAA/Cr值(分别为1.22±0.31和1.19±0.42,1.46±0.35和1.43±0.41)均低于对照组(分别为1.69±0.33和1.66±0.47),差异有统计学意义(均P0.05);研究组治疗前后左右侧海马Cho/Cr值(分别为1.58±0.39和1.59±0.46,1.55±0.43和1.53±0.42)高于对照组(分别为1.26±0.42和1.31±0.47),差异有统计学意义(均P0.05);研究组治疗后左右侧海马NAA/Cr值(分别为1.46±0.35和1.43±0.41)均高于治疗前(分别为1.22±0.31和1.19±0.42),差异有统计学意义(均P0.05)。结论氟西汀可能改变脑卒中后抑郁患者海马神经元的代谢异常。     

1H-MRS of hippocampus in patients after first manic episode

Objectives. The investigation of the pathophysiology of bipolar disorder in patients at disease onset is a strategy to avoid the confounding effect of progression of disease or duration of treatment. Our purpose was to investigate in vivo neuronal metabolites in the hippocampus of bipolar disorder patients using proton magnetic resonance spectroscopy (¹H-MRS) within 3 months after their first manic episode. Methods. Fifty-eight BD I patients meeting DSM-IV criteria following their first episode of mania and 27 healthy subjects were studied using ¹H-MRS with a 3.0 T Philips Achieva scanner. Voxels with 30 × 15 × 15 mm were placed in the hippocampus on both sides of the brain and the signal was collected using a PRESS sequence with TE = 35 ms and TR = 2000 ms. Data analysis was performed using the LC Model software. Results. N-Acetyl-aspartate (NAA), choline (Cho), myo-inositol (mI), creatine (Cre) and glutamine + glutamate (Glx) levels were compared between the groups and no statistically significant differences were found. Conclusions. Our results suggest that early in the course of BD there are no alterations in neuronal metabolism or vulnerability in the hippocampus after the first manic episode.     

A study of the relationship between the seizure focus and 1H-MRS in temporal lobe epilepsy and frontal lobe epilepsy

Several studies of temporal lobe epilepsy (TLE) patients have investigated the relationship between the seizure focus and 1H magnetic resonance spectroscopy (1H-MRS). There have also been a few reports in other types of partial epilepsy. We examined the relationship between the seizure focus and the reduction in N-acetylaspartate: creatine (NAA : Cr) ratio using 1H-MRS in both TLE and frontal lobe epilepsy (FLE) patients. We studied 21 patients with unilateral TLE and seven patients with unilateral FLE. We used a 1.5 Tesla magnetic resonance unit (Signa Horizon; General Electric). Approximately 15 x 15 x 20 mm3 voxel of interest (VOI) was placed over the anterior portion of the bilateral hippocampus in the TLE patients, and the anterodorsal position of bilateral frontal lobe in the FLE patients. The seizure focus was identified by interictal scalp electro-encephalogram (EEG). In the TLE patients the NAA : Cr ratios were reduced in the seizure focus, while in the FLE patients they were not always reduced in the seizure focus. In the TLE patients the coincidence rate between the seizure focus and the reduction in the NAA:Cr ratio was 90% (19 of 21 patients), while in the FLE patients the coincidence rate was only 57% (four of seven patients).     

Axonal injury and overall tissue loss are not related in primary progressive multiple sclerosis

BACKGROUND: There is an increasing body of evidence that magnetic resonance imaging-occult tissue damage is an important component of primary progressive multiple sclerosis (PPMS) pathology. Proton magnetic resonance spectroscopy (1H-MRS) can be used to measure in vivo whole-brain N-acetylaspartate (WBNAA) concentrations, the decrease of whose levels is considered a marker of neuronal-axonal injury. OBJECTIVES: To study WBNAA 1H-MRS as a tool to provide information about irreversible brain damage in PPMS and to investigate the relationship between WBNAA and other magnetic resonance imaging measures of MS disease burden, including brain atrophy. METHODS: The following magnetic resonance pulse sequences of the brain were obtained from 32 patients with PPMS and 16 age-matched healthy subjects: (1) dual-echo turbo spin-echo; (2) T1-weighted spin-echo; and (3) 1H-MRS to measure WBNAA concentration. Brain total lesion volumes were measured. Normalized brain volumes were calculated using a fully automated technique. Absolute WBNAA amounts were calculated using a phantom replacement method and were then corrected for individual subjects' brain size. RESULTS: Levels of WBNAA concentrations and normalized brain volumes were significantly lower in patients with PPMS (mean values, 10.2 mm and 1500.0 mL, respectively) than in healthy controls (mean values, 12.9 mm and 1585.2 mL). Both WBNAA concentrations and normalized brain volumes were included as independent factors in the final model of a multivariable analysis predicting the subjects' condition. No significant correlations were found between WBNAA values and normalized brain volumes, WBNAA and T2-weighted or T1-weighted lesion volumes. CONCLUSIONS: Axonal-neuronal damage in the brain of patients with PPMS seems to occur, at least partially, independently of the burden of magnetic resonance imaging-visible lesions. Whole-brain N-acetylaspartate values and normalized brain volumes were unrelated in this cohort, thereby suggesting that 1H-MRS and atrophy assessment may provide in vivo complementary information about the actual extent of brain damage in PPMS.     

A case of adult-onset type II citrullinemia with comorbid epilepsy even after liver transplantation

The current study using single case voxel-based morphometry (VBM) of magnetic resonance imaging (MRI) and 1H-MR-spectroscopy (1H-MRS) explores the neural background of unexplained seizure attacks and electroencephalography (EEG) abnormalities persisting even after liver transplantation in a patient with adult-onset type II citrullinemia (CTLN2). Although the MRI had shown no gross abnormality, the VBM revealed significantly smaller-than-normal regional volume in the left hippocampus of the patient as compared with 111 age-matched controls. 1H-MRS further indicated reduction of all metabolite concentrations in the left hippocampus compared with those in the right homolog region, with the single exception of elevated glutamate concentration. These results are similar to those of patients with mesial temporal lobe epilepsy (TLE), although CTLN2-complicated mesial TLE has rarely been reported. In contrast to TLE, periictal asterixis and interictal slow activities on EEG support another possibility that the patient might have slight metabolic encephalopathy even after the liver transplantation.     

Absence of thallium-201 brain uptake in progressive multifocal leukoencephalopathy in AIDS patients

OBJECTIVE: To evaluate the presence of thallium-201 brain uptake determined by thallium-201 brain SPECT (Tl-201 SPECT) in patients with progressive multifocal leukoencephalopathy (PML) and AIDS. MATERIAL AND METHODS: Six AIDS patients with stereotactic biopsy diagnosis of PML were prospectively evaluated with Tl-201 SPECT, Magnetic Resonance Imaging (MRI), and proton magnetic resonance spectroscopy (1H-MRS). Tl-201 SPECT results were compared with 2 patients with AIDS and biopsy proven primary CNS lymphoma. RESULTS: In all patients with PML, Tl-201 SPECT studies showed lack of uptake while MRI demonstrated subcortical white matter focal brain lesions and 1H-MRS disclosed metabolic abnormalities. Intense thallium uptake (uptake ratios of 3.2 and 5.6) was demonstrated in the 2 patients with primary CNS lymphoma. CONCLUSIONS: The present study shows that PML lesions are not detectable on Tl-201 SPECT while MRI and 1H-MRS demonstrate abnormalities, and intense thallium-201 uptake may be detected in primary CNS lymphoma. These results suggest that Tl-201 SPECT is a method which, combined with other non-invasive techniques such as MRI and 1H-MRS, may help in the diagnostic approach of PML and to differentiate PML from other high proliferative brain lesions characterized by positive thallium uptake.     

Reproducibility of Proton Magnetic Resonance Spectroscopy Imaging Measurements of Normal Human Hippocampus at 1.5 T: Clinical Implications

The authors investigate the reproducibility of metabolite signals measured with proton magnetic resonance spectroscopy (1H-MRS) acquired from the human hippocampus in controls and in a phantom. Two 1H-MRS studies separated by 3 weeks were performed in 8 healthy volunteers and in a phantom. N-acetyl compounds (NA), choline (Ch), and creatine (Cr) peak areas and ratios were measured and compared using percentage variation, and Pearson Correlation Coefficient at the level of every voxel, the level of 1 hippocampus (5 voxels), and the level of 2 hippocampi (10 voxels). Sensitivity for observing clinically significant between-session 1H-MRS changes was evaluated using the reliable change index. Reproducibility measures for metabolite peak areas were only moderately concordant with percentage variation ranging from 14% to 20% for NA, Cho, and Cr. Stability was much improved when NA ratios and sum of multiple voxels were considered. Between-session NA/(Cho + Cr) changes greater than 22%, 12%, and 10% in one given participant can be detected with a 90% confidence interval when considered at the single-voxel level, the level of a single hippocampus, or the level of both hippocampi, respectively. Left-right asymmetry indices showed similar and limited inter-hemispheric asymmetry in repeated examination. This study suggests that 1H-MRS reproducibility performance is adequate for the study and monitoring of human hippocampus function when NA ratios and the sum of multiple voxels are considered. Individual metabolite peaks and single-voxel measurements have low reproducibility at 1.5 T and should be used only with clearly established statistical parameters.