1H-MRS对碘异常引起脑损伤的诊断价值

目的 探讨氢质子磁共振波谱分析（^1H-MRS）在碘异常引起脑损伤病变中的应用价值。方法 收集临床诊断碘异常引起脑损伤的病例28例，其中低碘组16例，高碘组12例。使用西门子1．5TMPd，多体素相位矩阵扫描。检测低碘组和高碘组病人海马区与正常参照区域的代谢物浓度，利用SPSS12．0分析各种代谢物的变化。结果 ^1H-MRS示低碘组胆碱降低、γ-氨基丁酸、N-乙酰天门冬氨酸减少；高碘组胆碱增加、谷氨酸升高，γ-氨基丁酸、N-乙酰天门冬氨酸减少。结论 ^1H-MRS在碘异常引起脑损伤病变定性诊断中有重要的临床价值。     

氢质子磁共振波谱在轻度认知障碍中的诊断价值

目的探讨氢质子磁共振波谱分析（1H．MRS）在轻度认知功能障碍（MCI）诊断中的应用价值。方法回顾性分析22例MCI患者接受’H．MRS检查的资料,并与18例年龄、性别、受教育程度相匹配的认知功能正常的健康体检者进行对照。所有受检者均为右利手,采用激励回波采样模式检测,计算双侧大脑额中回皮质下白质区和双侧海马的N-乙酰天冬氨酸／肌酸（NAA／Cr）、肌醇／肌酸（mI／Cr）,肌醇／NAA（mI／NAA）等的比值,并比较各组比值间的差异。结果①MCI组的左额中回皮质下白质、左海马、右海马NAA／Cr比值分别为（1．29±0．18）、（1．30±0．18）、（1．20±0．23）,均低于对照组的（1．83±0．14）、（1．54±0．22）、（1．37±0．16）,差异均有统计学意义（P〈0．05）;MCI组的右额中回皮质下白质NAA／Cr比值为（1．32±0．19）,低于对照组的（1．35±0．24）,差异无统计学意义（P〉0．05）。②MCI组的左额中回皮质下白质、左海马、右海马mI／Cr比值分别为（0．66±0．12）、（1．02±0．14）、（0．68±0．06）,均高于对照组的（0．56±0．09）、（0．89±0．09）、（0．52±0．05）,差异均有统计学意义（P〈0．05）;MCI组的右额中回皮质下白质mI／Cr比值为（0．56-4-0．08）,低于对照组（O．58±0．07）,差异无统计学意义（P〉0．05）。⑧MCI组的左额中回皮质下白质、左海马、右海马mI／NAA比值分别为（0．52±0．12）,（0．80-t-O．15）,（0．59±0．13）,均高于正常对照组的（0．30±0．04）,（0．59±0．10）,（0．39±0．06）,差异均有统计学意义（P〈0．05）;MCI组的右额中回皮质下白质mI／NAA比值为0．44±0．09,与正常对照组的0．44±0．11比较,差异无统计学意义（P〉0．05）。结论1H－MRS检测MCI患者的左额中回皮质下白质、双侧海马NAA／Cr比值低于正常对照组,mI／Cr和mI／NAA比值高于正常对照组。这些指标的变化可为MCI的早期诊断提供依据。     

Proton magnetic resonance spectroscopy reveals central neuroaxonal impairment in systemic sclerosis

OBJECTIVE:. Involvement of the central nervous system (CNS) in systemic sclerosis (SSc) is rare. Proton magnetic resonance spectroscopy (1H-MRS) assesses in vivo cerebral metabolites. We investigated the biochemical modifications of the CNS in SSc. METHODS: N-acetylaspartate/creatine ratio (NAA/Cr) and choline/creatine ratio (Cho/Cr) at right centrum semiovale (RCS) and at right basal ganglia (RBG) were evaluated by 1H-MRS in 12 patients with limited (lSSc) and 8 patients with diffuse SSc (dSSc) and 20 control subjects. RESULTS: With 1H-MRS, a significant reduction of NAA/Cr ratio at RBG (p < 0.02) and at RCS (p < 0.002) was detected in SSc patients. Cho/Cr ratio was increased (p < 0.02) in the RCS, but not in RBG. In patients with lSSc, a significant reduction of NAA/Cr was detected in RCS but not in RBG. CONCLUSION: Evidence of neuroaxonal damage strongly suggests the existence of CNS involvement in SSc.     

Clinical brain proton magnetic resonance spectroscopy for management of Alzheimer's and sub-cortical ischemic vascular dementia in older people

This study examined the clinical usefulness of magnetic resonance spectroscopy (MRS) performed using an automated single voxel technique at 1.0 T field strength in a district general hospital magnetic resonance (MR) scanner in the assessment of older people referred to a memory clinic with suspected dementia. Of 50 elderly subjects (M:F 20:30) examined and followed-up clinically over more than 2 years, 20 had clinical Alzheimer's disease (AD), 18 had clinical vascular dementia, six had mixed features and three were normal. Three normal volunteers were also studied. MRS was performed at the same time as structural magnetic resonance imaging (MRI), added <15 min to the examination and was well-tolerated in all patients studied. Patients with AD had significantly higher myoinositol/creatine (MI/Cr) ratios (mean +/- S.D.: 0.82 +/- 0.04) compared to those with vascular dementia (mean +/-S. D.: 0.71 +/- 0.07, P<0.00001) and normal subjects (mean +/- S.D.: 0.72 +/- 0.036, P<0.0002); there was little overlap between the AD and vascular groups. The mixed dementia group also had significantly higher MI/Cr ratios (mean +/- S.D.: 0.80 +/- 0.05) than vascular dementia (P<0.01) and normal (P<0.03) groups, but with considerable overlap. No significant differences were shown for N-acetyl aspartate or choline/creatine ratios between the different clinical groups. These data suggest that MI/Cr ratios can distinguish patients with AD from normal subjects and those with sub-cortical ischemic vascular dementia and that MRS will be useful to clinicians managing persons with AD in a district general hospital setting.     

Cerebral abnormalities in patients with cirrhosis detected by proton magnetic resonance spectroscopy and magnetic resonance imaging

Hepatic encephalopathy is a common problem in cirrhosis. The pathogenesis of this complication of advanced liver disease still remains unclear. Magnetic resonance spectroscopy was used to assess prospectively cerebral metabolism in 51 patients with histologically proven cirrhosis (Child-Pugh classes A, B, and C, 18, 18, and 15, respectively) and 36 healthy volunteers. According to the results of psychometric tests, overt hepatic encephalopathy, subclinical encephalopathy, and no encephalopathy were found in 14, 21, and 16 patients, respectively. Myoinositol/creatine ratios in gray (.36 +/- .17) and white (.35 +/- .22) matter voxel were reduced significantly (P < .0001) in cirrhotic patients compared with healthy volunteers (gray matter, .51 +/- .11; white matter, .64 +/- .16). In addition, patients showed a significant reduction (P = .024) in white matter choline/creatine ratio (.77 +/- .27) compared with controls (.92 +/- .25), and glutamine/glutamate level was elevated in cirrhotic patients compared with controls (gray matter, P < .0001; white matter, P = .036). Changes in cerebral myoinositol and glutamine/glutamate levels correlated significantly with the severity of hepatic encephalopathy (P < .0001). However, these metabolic alterations were also detected in patients without hepatic encephalopathy (normal psychometric test results). N-acetyl aspartate/creatine ratios did not differ between patients and controls. Magnetic resonance imaging detected bright basal ganglia in 37 patients, which correlated significantly with portal-systemic shunting and elevation of glutamine/glutamate, but not with the degree of hepatic encephalopathy. In conclusion, magnetic resonance imaging and spectroscopy showed that alterations of cerebral metabolism are common in patients with cirrhosis, even without evidence of clinical or subclinical hepatic encephalopathy.(Hepatology 1997 Jan;25(1):48-54)     

MR and 1H MR spectroscopy of the brain in patients with liver cirrhosis and early stages of hepatic encephalopathy

BACKGROUND/AIMS: Hepatic encephalopathy is a serious problem in patients with liver cirrhosis and precise pathophysiological mechanisms responsible for encephalopathy are not fully understood. Magnetic resonance imaging and magnetic resonance spectroscopy can be used to detect specific morphological and metabolic abnormalities in the brain even in patients with early stages of hepatic encephalopathy. METHODOLOGY: Twenty patients with liver cirrhosis and 14 patients with grade I-II hepatic encephalopathy were studied with magnetic resonance and proton magnetic resonance spectroscopy. Localized magnetic resonance spectra were acquired in the parietal gray/white matter regions and basal ganglia. Control group consisted of 20 healthy volunteers. RESULTS: Frequency and degree of brain atrophy and bilateral signal hyperintensities in globus pallidus were similar in groups with liver cirrhosis and with encephalopathy. Decreased myoinositol, choline and increased glutamine levels were noted in both groups whereas N-acetylaspartate levels were unchanged. The statistically significant differences between cirrhotic and encephalopathic groups were observed only in myoinositol/creatine ratio in basal ganglia. There were no significant differences in metabolic concentrations between parietal and basal ganglia regions. CONCLUSIONS: Metabolic brain alterations occur earlier than clinical evidence of hepatic encephalopathy but there is no correlation between presence of symptoms encephalopathy and magnetic resonance and magnetic resonance spectroscopy findings.     

Effects of heavy drinking, binge drinking, and family history of alcoholism on regional brain metabolites

BACKGROUND: The main goals are to investigate the effects of chronic active heavy drinking on N-acetylaspartate (NAA) and other metabolites throughout the brain and to determine whether they are affected by family history (FH) of alcoholism and long-term drinking pattern. METHODS: Forty-six chronic heavy drinkers (HD) and 52 light drinkers (LD) were recruited from the community and compared on measures of regional brain structure using magnetic resonance imaging and measures of common brain metabolites in gray matter (GM) and white matter (WM) of the major lobes, subcortical nuclei, brainstem, and cerebellum using short-echo time magnetic resonance spectroscopic imaging. Regional atrophy-corrected levels of NAA, myoinositol (mI), creatine, and choline-containing metabolites were compared as a function of group, FH of alcoholism, and bingeing. RESULTS: Frontal WM NAA was lower in FH-negative HD than FH-positive HD and tended to be lower in women than men. Creatine-containing metabolites in parietal GM were higher in HD than LD. FH-negative compared with FH-positive HD also had more mI in the brainstem and tended to have lower NAA and more mI in frontal GM. Although parietal GM NAA was not significantly lower in HD than LD, it was lower in non-binge drinkers than bingers. Frontal WM NAA was lower in HD than LD, with the difference driven by a small number of women, FH-negative HD, and older age. Lower frontal WM NAA in HD was associated with lower executive and working memory functions and with lower P3b amplitudes at frontal electrodes. CONCLUSIONS: Community-dwelling HD who are not in alcoholism treatment have brain metabolite changes that are associated with lower brain function and are likely of behavioral significance. Age, FH, and binge drinking modulate brain metabolite abnormalities. Metabolite changes in active HD are less pronounced and present with a different spatial and metabolite pattern than reported in abstinent alcoholics.     

不同认知水平的广泛性脑萎缩患者磁共振波谱分析

目的 观察不同认知水平的广泛性脑萎缩患者脑内生化物质含量的差异. 方法 按照美国精神障碍诊断与统计手册第4版(DSM-Ⅳ)和认知功能障碍的诊断标准将33名广泛性脑萎缩患者分为阿尔茨海默病(AD)组14例、遗忘型轻度认知功能损害(aMCI)组9例和认知功能正常组10例.所有研究对象接受神经心理量表检测,然后采用1.5-T MR系统对左侧额叶皮质和左侧海马进行氢质子磁共振波谱(1H-MRS)检测分析. 结果 广泛性脑萎缩AD组的左侧海马和左侧额叶皮层的N-乙酰天门冬氨酸(NAA)/肌酸(Cr)值较认知正常组分别降低10.2%和5.3%.胆碱复合物(Cho)/Cr值分别升高17.5%和16.7%,肌醇(MI)/Cr值分别升高39.5%和19.2%.与aMCI组比较,广泛性脑萎缩AD组的左侧海马NAA/Cr值降低6.4%,左侧海马和左侧额叶皮层的Cho/Cr值分别升高9.3%和12.3%,左侧海马和左侧额叶皮层的MI/Cr值分别升高30%和17%,而左侧额叶皮层的NAA/Cr值在两者间差异无统计学意义.广泛性脑萎缩aMCI组的左侧海马NAA/Cr值比正常组降低4.1%、Cho/Cr值比认知正常组升高7.5%,但是左侧额叶皮层的生化改变在两组间差异均无统计学意义. 结论 不同认知水平的广泛性脑萎缩患者存在脑内神经生化物质的变化.左侧海马NAA/Cr值的降低、左侧海马和左侧额叶皮质Cho/Cr和MI/Cr值的升高有助于预测aMCI进展为AD;左侧海马NAA/Cr降低和Cho/Cr升高有助于鉴别广泛性脑萎缩伴aMCI患者与广泛性脑萎缩认知功能正常的患者.     

Longitudinal changes during aging using proton magnetic resonance spectroscopy

OBJECTIVE: We aimed to examine the longitudinal change in proton magnetic resonance spectroscopy ((1)H-MRS) visible metabolites (N-acetyl aspartate [NAA], creatine [Cr], choline [Cho], and myo-Inositol [mI]) in brains of elderly individuals over 3 years and relate them to cognitive function. METHODS: Neurologically and psychiatrically normal volunteers (n = 40) were examined at baseline and 3 years later with (1)H-MRS in two voxels (frontal white matter n = 29, and occipitoparietal gray matter n = 36) and with detailed neuropsychological assessments. Longitudinal analyses were performed with age, educational level, sex, and white matter hyperintensities (WMH) in voxels as covariates. RESULTS: Frontal mI was significantly increased over time in male participants, but all other metabolites were stable over time. Neuropsychological performance was not significantly changed over 3 years, and there was no relationship between change in metabolite levels and change in neuropsychological function. CONCLUSIONS: MRS-visible metabolites are stable in elderly persons over 3 years, with the exception of mI which shows an increase. Increasing mI may be a marker of aging or a preclinical neurodegenerative process. MRS changes do not correlate with change in neurocognitive function during aging.     

质子磁共振波谱评价颈内和大脑中动脉狭窄与闭塞的脑代谢研究

目的探讨质子磁共振波谱(1H-MRS)在单侧颈内动脉(ICA)和大脑中动脉(MCA)重度狭窄与闭塞中的应用价值。方法32例单侧ICA或MCA重度狭窄或闭塞患者(ICA18例,MCA14例)行1H-MRS检查,测量患侧和对侧大脑半球半卵圆中心N-乙酰天门冬氨酸(NAA)、胆碱(Cho)和肌酸(Cr)的波峰下面积,比较患侧和对侧各代谢物峰下面积比值NAA/Cho、NAA/Cr和Cho/Cr的差异,并观察有无乳酸(Lac)峰出现。结果1H-MRS显示患侧半卵圆中心的NAA/Cho、NAA/Cr低于对侧,差异有显著性意义(P<0.01),Cho/Cr高于对侧,差异有显著性意义(P<0.01),5例患者于患侧检测到Lac峰。结论1H-MRS能够早期发现ICA或MCA重度狭窄或闭塞患者缺血脑组织的代谢异常,从代谢产物角度评价脑缺血程度,对于早期治疗和判断预后具有重要价值。     

Longitudinal brain metabolic characterization of chronic alcoholics with proton magnetic resonance spectroscopy

BACKGROUND: Proton magnetic resonance spectroscopy may elucidate the molecular underpinnings of alcoholism-associated brain shrinkage and the progression of alcohol dependence. METHODS: Using proton magnetic resonance spectroscopy, we determined absolute concentrations of -acetylaspartate (NAA), creatine/phosphocreatine (Cr), and choline (Cho)-containing compounds and -inositol (mI) in the anterior superior cerebellar vermis and frontal lobe white matter in 31 alcoholics and 12 normal controls. All patients were examined within 3 to 5 days of their last drink. Patients who did not relapse were again studied after 3 weeks and 3 months of abstinence by using an on-line repositioning technique that allows reliable localization of volumes of interest (VOIs). RESULTS: At 3 to 5 days after the last drink, frontal white matter metabolite concentrations were not significantly different from those of normal controls, whereas brain tissue in the VOI was reduced. Cerebellar [NAA] and [Cho] and brain and cerebellar volumes were decreased, but [Cr], [mI], and VOI brain tissue volume were not significantly different. Eight patients relapsed before 3 weeks (ER), 12 relapsed between 3 weeks and 3 months (LR), and 11 did not relapse (NR) during 3 months. Cerebellar [NAA] was reduced only in ER patients, despite the fact that ER patients drank for significantly fewer years and earlier in life than LR or NR patients. After 3 months, in the 11 continuously abstinent patients, cerebellar [NAA] and brain and cerebellar volumes increased; cerebellar [Cho], [Cr], and [mI] and VOI brain tissue did not change significantly. CONCLUSIONS: Decreased [NAA] and [Cho] in cerebellar vermis indicate a unique sensitivity to alcohol-induced brain injury. Cerebellar [NAA] increased with abstinence, but reduced [Cho] persisted beyond 3 months. Further studies are needed to determine whether low cerebellar [NAA] is a risk factor for, or consequence of, malignant, early-onset alcoholism.     

Do white matter changes have clinical significance in Alzheimer's disease?

BACKGROUND: Although white matter changes visible with MRI are generally considered to result from ischemia, it has become clear that these changes also appear in patients with Alzheimer's disease (AD). However, their significance in AD is unknown. OBJECTIVE: We evaluated the clinical significance of white matter changes in AD. METHODS: Ninety-six AD patients (79.4 +/- 5.92 years old) and 48 age-matched control subjects (80.0 +/- 7.03 years old) participated in the study. Three neuroradiologists assessed the degree of periventricular hyperintensities (PVH) and deep white matter hyperintensities (DWMH) using a modified Fazekas' rating scale. We examined whether there was a difference in the severity and the histogram pattern of the white matter changes, or in vascular factors (hypertension, diabetes mellitus, and ischemic heart disease) between the two groups. We also analyzed the association between the severity of the white matter changes and the degree of dementia (MMSE score and disease duration). RESULTS: There were no differences in the vascular factors between AD and control subjects. The degree of PVH in AD was severe compared with that in the control subjects. In histograms of the number of subjects with each degree of PVH severity, the distribution of AD patients had peaks at both the low and intermediate degrees of PVH, while most of the controls had a low degree of PVH. There was no difference in the degree or the histogram pattern of DWMH between the two groups. The severity of white matter changes was not associated with severity of dementia in AD. CONCLUSIONS: Although PVH might have several causative factors, and may have some clinical significance, the change itself does not contribute to the progression of AD.     

盐酸多奈哌齐干预血管性痴呆患者后的磁共振波谱分析

目的 利用氢质子磁共振波谱分析(1 H-magnetic resonance spectroscopy,1 H-MRS)技术研究脑卒中后血管性痴呆(vascular dementia,VD)患者颞叶海马区细胞代谢水平及给予盐酸多奈哌齐后,细胞代谢水平的改变及其与临床症状的关系.方法 脑卒中VD组18例,男性16例,女性2例,平均年龄(76.9±2.7)岁,符合痴呆的《神经病诊断和统计手册》第4版(DSM-Ⅳ)诊断标准;脑卒中非VD组13例,男性11例,女性2例,平均年龄(76.2±3.6)岁;正常对照组来源于门诊就诊者,共14例,男性12例,女性2例,平均年龄(75.1±2.4)岁.所有入组者均行简易精神状态量表(MMSE)、日常生活活动能力量表(ADL)、汉密尔顿抑郁量表(HAMD)评分以及1H-MRS检测患者双侧颞叶海马区细胞代谢水平.脑卒中VD组在盐酸多奈哌齐治疗6个月后复查MMSE评分及1H-MRS检查.结果 脑卒中VD组患者双侧颞叶海马区N-乙酰天门冬氨酸盐(NAA)/肌酸(Cr)比值较正常对照组及脑卒中非VD组均有显著下降(F=4.23、4.98,均P＜0.05);而双侧胆碱复合物(Cho)/Cr比值较正常对照组显著升高(P=0.005、0.010),较脑卒中非VD组左侧有显著升高(P=0.038),但右侧差异无统计学意义(P=0.066).脑卒中非VD组NAA/Cr比值及Cho/Cr比值较正常对照组虽有变化,但差异无统计学意义.脑卒中VD组MMSE评分与双侧颞叶海马区NAA/Cr及Cho/Cr比值有相关性,且MMSE分数越低,NAA/Cr比值越低,而Cho/Cr比值则越高.应用盐酸多奈哌齐干预治疗脑卒中VD组患者6个月后,患者MMSE及ADL评分均有显著提高(均P＜0.05);双侧颞叶海马区NAA/Cr比值无明显改善(t=-2.02、-2.04,均P＞0.05),而双侧颞叶海马区Cho/Cr比值有显著下降(t=2.86、2.23,均P＜0.05).结论 1 H-MRS技术可能有助于早发现脑卒中后血管性痴呆;盐酸多奈哌齐可通过调整脑内胆碱能系统,改善血管性痴呆患者的认知功能.     

Evaluation of in vivo cerebral metabolism on proton magnetic resonance spectroscopy in patients with impaired glucose tolerance and type 2 diabetes mellitus

The aim of this study was to investigate possible metabolic alterations in cerebral tissues on magnetic resonance spectroscopy (MRS) in patients with impaired glucose tolerance (IGT) and with type 2 diabetes mellitus (T2-DM). Twenty-five patients with T2-DM, 13 patients with IGT, and 14 healthy volunteers were included. Single-voxel spectroscopy (TR: 2000 ms, TE: 31 ms) was performed in all subjects. Voxels were placed in the frontal cortex, thalamus, and parietal white matter. N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and myo-inositol (MI)/Cr ratios were calculated. Frontal cortical Cho/Cr ratios were increased in patients with IGT compared to control subjects. Parietal white matter Cho/Cr ratios were significantly higher in patients with IGT when compared to patients with T2-DM. In the diabetic group, frontal cortical MI/Cr ratios were increased, and parietal white matter Cho/Cr ratios were decreased when compared to the control group. Frontal cortical NAA/Cr and Cho/Cr ratios and parietal white matter Cho/Cr ratios were decreased in diabetic patients with poor glycemic control (A1C>10%). A1C levels were inversely correlated with frontal cortical NAA/Cr and Cho/Cr ratios and with parietal white matter Cho/Cr ratios. T2-DM and IGT may cause subtle cerebral metabolic changes, and these changes may be shown with MRS. Increased Cho/Cr ratios may suggest dynamic change in membrane turnover in patients with IGT. Diabetic patients with poor glycemic control may be associated with neuronal dysfunction/damage in brain in accordance with A1C levels and, in some, extend with insulin resistance.     

Thalamic neuronal dysfunction and chronic sensorimotor distal symmetrical polyneuropathy in patients with type 1 diabetes mellitus

Aims/hypothesis  Although clear peripheral nerve pathological abnormalities have been demonstrated in diabetic peripheral neuropathy (DPN), there is little information with regard to brain involvement. Our aim was to use in vivo proton magnetic resonance specroscopy (H-MRS) in patients with DPN in order to assess the neuro-chemical status of the thalamus, which acts as the gateway to the brain for somatosensory information. Methods  Participants included 18 type 1 diabetic men (eight without DPN, ten with DPN) and six non-diabetic healthy volunteers, who all underwent detailed clinical and neurophysiological assessments yielding a Neuropathy Composite Score (NCS) derived from Neuropathy Impairment Score of the Lower Limbs plus seven tests of nerve function prior to investigation via a single-voxel H-MRS technique, which was used to sample ventral posterior thalamic parenchyma. Spectroscopic resonances including those due to N-acetyl aspartate (NAA) were assessed at both short and long echo-time, providing putative indicators of neuronal function and integrity, respectively. Results  At long echo-time we observed significantly lower NAA:creatine (p = 0.04) and NAA:choline (p = 0.02) ratios in DPN patients than in the other groups. No group differences were detected at short echo-time. We found a significant positive association between both sural amplitude (ρ = 0.61, p = 0.004) and nerve conduction velocity (r = 0.58, p = 0.006) and NAA:creatine signal among participants with diabetes. Vibration detection threshold (ρ = −0.70, p = 0.004) was significantly related to NAA:choline ratio. Heart rate variability with deep breathing (ρ = −0.46, p = 0.05) and NCS (ρ = −0.53, p = 0.03) were significantly related to NAA:creatine ratio. Conclusions/interpretation  The significantly lower NAA:creatine ratio in DPN is suggestive of thalamic neuronal dysfunction, while the lack of difference in short echo-time between the groups does not suggest neuronal loss. Taken together with the observed correlations between NAA and neurophysiological assessments, these findings provide evidence for thalamic neuronal involvement in DPN.     

Cigarette smoking exacerbates chronic alcohol-induced brain damage: a preliminary metabolite imaging study

BACKGROUND: Cigarette smoking is common among alcohol-dependent individuals. Nevertheless, previous research has typically not accounted for the potential independent or compounding effects of cigarette smoking on alcohol-induced brain injury and neurocognition. METHODS: Twenty-four 1-week-abstinent recovering alcoholics (RAs; 14 smokers and 10 nonsmokers) in treatment and 26 light-drinking controls (7 smokers and 19 nonsmokers) were compared on measures of common brain metabolites in gray matter and white matter of the major lobes, basal ganglia, midbrain, and cerebellar vermis, obtained via multislice short-echo time proton magnetic resonance spectroscopic imaging. Smoking and nonsmoking RAs were also contrasted on measures of neurocognitive functioning, as well as laboratory markers of drinking severity and nutritional status. RESULTS: Chronic alcohol dependence, independent of smoking, was associated with lower concentrations of frontal N-acetylaspartate (NAA) and frontal choline-containing compounds, as well as lower parietal and thalamic choline. Smoking RAs had lower NAA concentrations in frontal white matter and midbrain and lower midbrain choline than nonsmoking RAs. A four-group analysis of covariance also demonstrated that chronic cigarette smoking was associated with lower midbrain NAA and choline and with lower vermian choline. In smoking RAs, heavier drinking was associated with heavier smoking, which correlated with numerous subcortical metabolite abnormalities. The 1-week-abstinent smoking and nonsmoking RAs did not differ significantly on a brief neurocognitive battery. In smoking RAs, lower cerebellar vermis NAA was associated with poorer visuomotor scanning speed and incidental learning, and in nonsmoking RAs lower vermis NAA was related to poorer visuospatial learning and memory. CONCLUSIONS: These human in vivo proton magnetic resonance spectroscopic imaging findings indicate that chronic cigarette smoking exacerbates chronic alcohol-induced neuronal injury and cell membrane damage in the frontal lobes of RAs and has independent adverse effects on neuronal viability and cell membranes in the midbrain and on cell membranes of the cerebellar vermis. Higher smoking levels are associated with metabolite concentrations in select subcortical structures. Greater consideration of the potential effects of comorbid cigarette smoking on alcohol-induced brain damage and other diseases affecting the central nervous system is warranted.     

Cerebral metabolic abnormalities in COPD patients detected by localized proton magnetic resonance spectroscopy.

STUDY OBJECTIVES: To investigate changes in the cerebral metabolism of patients with COPD, using localized in vivo proton magnetic resonance spectroscopy ((1)H MRS), and to evaluate the clinical significance of cerebral metabolic abnormalities in COPD patients. PATIENTS AND METHODS: Seventeen symptomatic COPD patients and 21 age-matched healthy volunteers participated in this study. All subjects underwent (1)H MRS, and neuropsychological tests (Wechsler memory scale-revised [WMS-R], color trail test, and grooved pegboard test) were performed by COPD patients. Magnetic resonance spectra were obtained from localized regions of parietal white matter (PWM) and occipital gray matter (OGM). Absolute levels of N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), and myo-inositol (mI) were calculated. RESULTS: In COPD patients, the mean (+/- SD) FEV(1) was 38 +/- 10% predicted, the PaCO(2) was 39 +/- 7 mm Hg, and the PaO(2) was 89 +/- 18 mm Hg, and these values did not exhibit statistical correlation with the levels of cerebral metabolites. NAA, Cr, and Cho levels in PWM were all significantly lower in COPD patients than in control subjects (p < 0.0125 [Bonferroni adjusted]). Neuropsychological parameters were lower in COPD patients compared with standardized values. However, they were not correlated with the levels of cerebral metabolites except for a positive correlation between the Cho level in PWM and the general memory quotient of WMS-R (r = 0.52; p < 0.05). CONCLUSIONS: Our results demonstrate that the cerebral metabolism is significantly altered in symptomatic COPD patients. The relationship between decreased Cho levels and memory dysfunction, and the clinical significance of other cerebral metabolic changes in COPD patients need to be further investigated.     

In vivo1H magnetic resonance spectroscopy‐derived metabolite variations between acute‐on‐chronic liver failure and acute liver failure

Background and Aims: Acute‐on‐chronic liver failure (ACLF), acute liver failure (ALF) and chronic liver disease (CLD) are common forms of liver failure and present with similar clinical profiles. The aim of this study was to compare brain metabolite alterations in all the three groups of patients with controls, using in vivo proton magnetic resonance spectroscopy (MRS), and to look for any significant differences in metabolites that may help in differentiating between these three conditions. Methods: Nine patients with ACLF, 10 with ALF, 10 patients with CLD and 10 age‐matched controls were studied. The relative concentrations of N‐acetylaspartate (NAA), choline (Cho), glutamine/glutamate (Glx) and myoinositol (mI) with respect to creatine (Cr) were measured. Results: ACLF (3.07±0.72), ALF (4.39±1.25) and CLD (3.15±0.69) patients exhibited significantly increased Glx/Cr ratios compared with controls (2.14±0.42). The NAA/Cr ratio was significantly decreased in both ACLF (mean=0.84±0.28) and CLD (mean=0.97±0.21) patients as compared with that in controls (mean=1.24±0.20). No significant difference among ALF, ACLF and CLD patients was noted in the Cho/Cr ratios. ACLF patients showed significantly lower mI/Cr and Glx/Cr ratios compared with the ALF group. Conclusion: In vivo proton MRS‐derived cerebral metabolite alterations in hepatic encephalopathy owing to ALF are significantly different from the one owing to ACLF and CLD; these may be due to the differences in the pathogenesis of these two overlapping clinical conditions.     

Brain metabolic alterations in adolescents and young adults with fetal alcohol spectrum disorders

BACKGROUND: Prenatal alcohol exposure affects brain structure and function. This study examined brain metabolism using magnetic resonance spectroscopy (MRS) and searched for regions of specific vulnerability in adolescents and young adults prenatally exposed to alcohol. METHODS: Ten adolescents and young adults with confirmed heavy prenatal alcohol exposure and a diagnosis within the fetal alcohol spectrum disorders (FASD) were included. Three of them had fetal alcohol syndrome (FAS), 3 had partial FAS (PFAS), and 4 had alcohol-related neurobehavioral disorder (ARND). The control group consisted of 10 adolescents matched for age, sex, head circumference, handedness, and body mass. Exclusionary criteria were learning disorders and prenatal alcohol exposure. Three-dimensional (1)H magnetic resonance spectroscopic imaging ((1)H MRSI) was performed in the cerebrum and cerebellum. Metabolite ratios N-acetylaspartate/choline (NAA/Cho), NAA/creatine (Cr) and Cho/Cr, and absolute metabolite intensities were calculated for several anatomic regions. RESULTS: In patients with FASD, lower NAA/Cho and/or NAA/Cr compared with controls were found in parietal and frontal cortices, frontal white matter, corpus callosum, thalamus, and cerebellar dentate nucleus. There was an increase in the absolute intensity of the glial markers Cho and Cr but no change in the neuronal marker NAA. CONCLUSIONS: Our results suggest that prenatal alcohol exposure alters brain metabolism in a long-standing or permanent manner in multiple brain areas. These changes are in accordance with previous findings from structural and functional studies. Metabolic alterations represent changes in the glial cell pool rather than in the neurons.     

Proton magnetic resonance spectroscopy and single photon emission computed tomography study of the brain in asymptomatic young hyperlipidaemic Asian Indians in North India show early abnormalities

OBJECTIVE: To evaluate brain metabolism and cerebral blood flow in young patients with hyperlipidaemia. PATIENTS AND METHODS: Proton magnetic resonance spectroscopy ((1)H MRS) and single photon emission computed tomography (SPECT) of the brain was carried out in 19 asymptomatic young patients with hyperlipidaemia (mean age 32.6 +/- 6.0 years, range 22-45 years) and 21 age-matched healthy controls divided into the following three groups; (i) hyperlipidaemics on pharmacological treatment (group 1, n = 13), (ii) hyperlipidaemics not on pharmacological treatment (group 2, n = 6) and (iii) control group of healthy subjects (group 3, n = 21). RESULTS: No statistical difference was observed in the brain metabolite ratios between controls and hyperlipidaemic patients (both treatment naive and treated) in the (1)H NMR study. Two hyperlipidaemic patients showed a lactate peak and one had a lipid peak. The SPECT study was abnormal in seven hyperlipidaemic patients. In the pooled data, 50% subjects with high serum triglyceride (TG) levels as opposed to 14% subjects with normal serum TG levels showed cerebral hypoperfusion. The choline/creatine (Cho/Cr) ratio of the occipital region of the brain showed correlation with the excess percentage of body fat (%BF) and low levels of high density lipoprotein cholesterol (HDL-C) compared to those with normal %BF and normal HDL-C levels, respectively, in pooled data of all subjects. The N-acetyl aspartate (NAA)/Cho ratio also showed correlation with hypercholesterolaemia. Serum TG levels were positively correlated with the NAA/Cr ratio (r = 0.62, P < 0.05) and the Cho/Cr ratio (r = 0.63, P < 0.05) in the parieto-temporal area in group 1 patients. CONCLUSION: The study revealed no difference in the brain metabolite ratios between controls and hyperlipidaemic patients, while some hyperlipidaemic patients showed abnormalities of cerebral blood flow. Brain metabolite ratios were also influenced by certain parameters of body composition and lipids. As abnormal body composition, hypertriglyceridaemia and low levels of HDL-C are prevalent in Asian Indians, such data are important and indicate a need for further study.