急性脑梗死患者脑组织磁共振波谱研究

目的研究基底节区急性脑梗死患者脑组织磁共振波谱(MRS)的改变。方法应用MRS检测50例一侧基底节区梗死患者(脑梗死组)及50例其他疾病患者(对照组)双侧基底节区的N-乙酰天冬氨酸(NAA)、胆碱复合物(Cho)、肌酸复合物(Cr)和乳酸(Lac)水平及NAA/Cr、Cho/Cr比值。结果脑梗死组病灶侧Cho及Cr水平均显著低于非病灶侧(均P<0.05),NAA、Lac水平及NAA/Cr、Cho/Cr比值的差异无统计学意义。脑梗死组病灶侧及非病灶侧Cho、NAA及Cr水平均明显低于对照组病灶对应区(P<0.001～0.05),而Lac水平明显高于对照组病灶对应区(均P<0.05)。与对照组病灶对应区比较,脑梗死组病灶侧Cho/Cr比值显著升高,非病灶侧NAA/Cr比值显著降低(均P<0.05)。结论基底节区梗死急性期病灶侧及对侧脑组织均有明显的代谢障碍,且病灶区代谢异常较对侧更明显。     

急性期脑梗死的磁共振化学位移成像研究

目的采用磁共振化学位移成像(CSI)研究急性期脑梗死不同部位代谢产物浓度变化 的差异及其与弥散加权成像(DWI)表现的相关性。方法28例发病3d内非腔隙性脑梗死患者完成 CSI和DWI检查。测算梗死区N-乙酰天门冬氨酸(NAA),肌酸(Cr),胆碱化合物(Cho)与对侧相应 正常脑区代谢产物比值(rNAA、rCr、rCho)及同侧乳酸／胆碱值(Lac／Cho),比较不同部位各代谢产物 相对浓度;比较:DWI上梗死区相对信号强度(rDWI)、表观弥散系数(rADC)值与代谢产物浓度的相 关性。结果(1)与对应脑区比较,急性期脑梗死灶内NAA明显降低,Lac明显增加(P<0.001),cr、Cho无显著变化(P=0.543,0.817)。(2)梗死核心区、内缘、外缘及正常组织间rNAA及Lac／Cho差异均有显著意义(均P<0.001),rCr及rCho各部位间差异无显著意义(P=0.266,0.737)。rNAA梗死外缘与正常区域间差异无显著意义(P=0.733);Lac／Cho外缘与正常区域差异有显著意义(P=0.003)。(3)急性期脑梗死rNAA与Lac／Cho(r=0.496)、rADC(r=0.405)成正相关,与rDWI成负相关(r=-0.432);Lac／Cho与rDWI成负相关(r=-0.587),与rADC成正相关(r=0.561)。结论(1)急性期梗死灶NAA降低局限于DWI高信号范围内,而Lac升高范围可超过NAA下降和DWI高信号区域,可能预示缺血半影区。(2)急性期梗死区La     

质子磁共振波谱用于帕金森病黑质代谢研究价值的探讨

目的探讨质子磁共振波谱（^1H MRS）技术在帕金森病（PD）黑质代谢变化研究中的价值。方法PD患者56例和正常对照30例行^1H MRS检查，测定双侧黑质的N-乙酰天门冬氨酸／肌酸（NAA／Cr）、N-乙酰天门冬氨酸／胆碱复合物（NAA／Cho）和胆碱复合物／肌酸（Cho／Cr）比值。结果PD患者和对照组黑质的NAA／Cr、Cho／Cr和NAA／Cho比值无显著性差异。PD患者的^1H MRS结果与UPDRS评分、H＆Y分级和病程均不存在显著相关性。结论目前的^1H MRS技术尚不能精准地反应PD患者黑质的代谢变化。     

磁共振波谱在脑胶质瘤放疗中的应用价值

目的：分析磁共振波谱（M RS ）在脑胶质瘤放疗的应用价值。方法选取2012‐01—2013‐12我院脑胶质瘤部分切除术后放疗患者30例，在放疗前后7 d予以M RS及M RI检查，观察患者肿瘤及周围区域放疗前后代谢物浓度变化。结果放疗后肿瘤强化区的NAA、Cho值均高于放疗前，NAA放疗前后变化差异有统计学意义（P＝0.022）；放疗后的NAA／Cr 、Cho／NAA 、Cho／Cr均降低，其中Cho／Cr变化差异有统计学意义（P＝0.004）。放疗后肿瘤强化区的NAA值均高于放疗前、Cho值低于放疗前，两个指标放疗前后变化差异均无统计学意义（P＞0.05）；放疗后的NAA／Cr 、Cho／NAA 、Cho／Cr均降低，其中Cho／Cr变化差异有统计学意义（P＝0.011）。结论脑胶质瘤放疗中应用MRS可清晰显示肿瘤及周围水肿区域放疗前后代谢变化情况，可作为了解放疗综合效果的主要手段。     

磁共振波谱分析在脑胶质瘤分级中的应用价值

目的分析氢质子磁共振波谱(~1H-MRS)分析在脑胶质瘤分级中的应用价值。方法回顾性分析我院2013-01—2016-06收治的经术后病理或活组织病理检查确诊的36例脑胶质瘤患者的临床资料,均行常规磁共振(MRI)及~1H-MRS检查,依据世界卫生组织(WHO)2007年分级方法分为低级别胶质瘤组(n=15)和高级别胶质瘤组(n=21),对比分析2组肿瘤占位核心实质区、瘤周区域及对侧镜像区胆碱复合物(Cho)、N-乙酰-L-天门冬氨酸复(NAA)、肌酐(Cr)脂质(Lip)、乳酸(Lac)。结果所有患者肿瘤占位核心实质的Cho/Cr比值均较对侧镜像区升高,NAA/Cr、NAA/Cho比值较对侧镜像区降低(P0.05)。高级别胶质瘤NAA/Cho比值低于低级别胶质瘤,而Cho/Cr高于低级别胶质瘤(P0.05)。高级别胶质瘤瘤周区域Cho/Cr比值较对侧镜像区升高,NAA/Cho比值较对侧镜像区降低(P0.05);低级别胶质瘤瘤周区域Cho/Cr比值较对侧镜像区升高,NAA/Cr、NAA/Cho比值较对侧镜像区降低(P0.05)。高级别胶质瘤组20例出现Lac峰,14例出现Lip;低级别胶质瘤组6例出现Lac峰,1例出现Lip峰。Cho/Cr比值与病理级别呈正相关(r=0.812,P0.05),而NAA/Cho比值与病理级别呈负相关(r=-0.634,P0.001),NAA/Cr与病理级别无明显相关性(r=-0.060,t=0.241)。结论氢质子磁共振波普能够有效显示脑胶质瘤患者肿瘤周围水肿区及肿瘤实质区的代谢变化情况,可为胶质瘤临床术前分级提供客观依据,提高诊断的准确性。     

脑干胶质瘤磁共振波谱分析

目的探讨磁共振波谱(Magnetic resonance spectroscopy,MRS)在脑干胶质瘤诊断中的意义。方法回顾性分析10例脑干胶质瘤的临床资料,肿瘤位于中脑1例,中脑脑桥1例,脑桥7例,延髓1例。均行MRS检查,对肿瘤区、肿瘤边缘区和正常对照区进行对照研究。结果MRS均显示肿瘤区N-乙酰天门冬氨酸(N-acetylaspartate,NAA)峰值下降,胆碱(Choline,Cho)峰上升。与肿瘤边缘区和正常对照区比较,肿瘤区NAA/Cr明显减低,Cho/Cr和Cho/NAA明显升高。星形细胞瘤4例,间变性星形细胞瘤1例,胶质母细胞瘤2例;另3例根据临床特点和影像学表现诊断为脑干胶质瘤。结论MRS可检测到脑干胶质瘤的代谢改变,具有无创、敏感、诊断准确的特点。     

磁共振波谱分析与癫痫临床

磁共振波谱(MRS)是一新兴无创性检查手段,已应用于癫痫的诊断及疗效评价。与MRI及PET相比,MRS 可更敏感的发现病灶。目前,1H MRS应用最广泛,颞叶癫痫患者病灶内NAA浓度、NAA／(Cho+Cr)比值明显降低, 部分单侧病灶患者会出现双侧NAA改变,是继发还是原发仍有争议;全面发作性癫痫患者额叶或丘脑也出现NAA／ (Cho+Cr)比值降低。癫痫发作后,还可观察到病灶内Glu含量升高、GABA含量降低,有效的抗癫痫治疗后,各指标 恢复到正常水平。31P MRS中Pcr／Pi比值降低、PME减少和pH值升高也见于癫痫发作后。总之,MRS可在生化代谢 水平来反映和评价疾病,已显示出极大地临床应用价值。     

脑梗死磁共振波谱分析的临床应用

磁共振波谱分析能定量检测脑梗死患者脑组织的生化代谢。脑梗死灶周围的Lac升高,而NAA正常或轻度降低可作为判断缺血半暗带的指标;通过检测比较NAA/Cr、mI/Cr、Cho/Cr及NAA/mI比值可辅助诊断血管性痴呆及其预后的判断;检测Glx/Cr、Cho/Cr的比值可辅助诊断卒中后抑郁障碍及其治疗效果的评价;NAA、Cho可作为卒中后失语语言功能区生化、代谢的指标。     

~1HMRS成像在急性期脑梗死中的应用

目的探讨氢质子磁共振波谱成像(1HMRS)在急性脑梗死早期诊断、评估预后中的临床价值。方法对30例急性期脑梗死患者于入院时及2w后分别进行磁共振(MRI)、1HMRS扫描及NIHSS评分,分析梗死灶中心及对侧镜像区各代谢物数值,计算梗死病灶N-乙酰天门冬氨酸(NAA)、肌酸(Cr)、胆碱化合物(Cho)与对侧相应正常脑区代谢产物比值(rNAA、rCr、rCho)及同侧乳酸/胆碱值(Lac/Cho),比较治疗前后各代谢产物相对浓度变化及与NIHSS相关性。结果梗死灶中心与对侧镜像区NAA、Lac、Cr比较差异有统计学意义(Z=-4.762,P=0.000;Z=-4.782,P=0.000;Z=-3.569,P=0.000);病灶侧治疗前后rNAA、rCr、rCho及Lac/Cho比值差异无统计学意义;NIHSS评分与NAA呈负相关,与Lac呈正相关(r=-0.623,P=0.000;r=0.468,P=0.009)。结论应用1HMRS分析技术,能无创性检测急性脑梗死代谢物的动态变化,为患者病情转归、疗效及预后判断提供更多临床依据。     

1H磁共振波谱技术及其在脑肿瘤诊断中的应用

磁共振波谱分析(Magnetic Resonance Spectroscopy,MRS)是目前唯一无损伤性检测活体器官和组织代谢、生化及化合物定量分析的技术,在形态成像的基础上,通过代谢成像提供被检测组织代谢物的化学信息.临床上以1H-MRS在脑部疾病中的应用研究最为广泛,技术也较为成熟.主要通过测定作为神经元内标物的N-乙酰天门冬氨酸(NAA)、胆碱(Cho),糖酵解终产物的乳酸(Lac)、肌酸(Cr)和谷氨酰胺(Glx)等的相对值,并计算NAA/Cr、NAA/Cho、Cho/Cr及Lac/Cr之间的比值,可以用来对脑胶质瘤进行分级、鉴别脑肿瘤的良恶性、手术疗效评价、监测肿瘤复发以及预后的判断.     

Evaluation of cerebral circulation and oxygen metabolism in infants using near-infrared light

Bedside monitoring of cerebral circulation or oxygen metabolism in infants to appropriately manage circulation and establish the oxygen dose, aiming at improving the neurological prognosis, is needed in general clinical practice. Near-infrared spectroscopy is used for measurements of neonatal cerebral Hb oxygen saturation, cerebral blood volume, cerebral blood flow and cerebral metabolic rate of oxygen. Near-infrared time-resolved spectroscopy is particularly useful for bedside evaluation of cerebral circulation and oxygen metabolism because of its simple measurement procedure. Combined evaluation of cerebral blood volume and cerebral Hb oxygen saturation is expected to contribute to treatment centering on the brain in neonatal medical care.     

Interictal cerebral metabolism in partial epilepsies of neocortical origin

We performed interietal [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG PET) in 24 patients with partial epilepsy of neocortical origin. Two-thirds of patients had regions of hypometabolism. The zone of intracranially recorded electrographic ictal onset was always located in a region of hypometabolism, in those with hypometabolism. Hypometabolic regions in partial epilepsies of neocortical origin were usually associated with structural imaging abnormalities. Regional hypometabolism occasionally occurred without localizing ictal scalp EEG and cerebral magnetic resonance imaging findings, however. FDG PET may be useful in directing placement of intracranial electrodes for presurgical evaluation of refractory neocortical seizures.     

Cerebral circulation and oxygen metabolism in Moyamoya disease of ischemic type in children

Cerebral rCBF, rOEF, rCMRO₂, and rCBV in moyamoya disease were studied by means of positron emmission tomography (PET), using ¹⁵O as a tracer. Steady-state methods with C¹⁵O₂ and ¹⁵O₂ were used to obtain the functional images of rCBF, rCMRO₂, and rOEF. The ¹⁵O single-inhalation method was used to obtain the rCBV image. Five children (two boys and three girls) with mean age of 11 years and eight normal volunteers with mean age of 31 years were included in the study. The symptoms of moyamoya disease were due to cerebral ischemia, such as transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND), and minor stroke. The interval between the latest ictus and PET scan ranged from 3 days to 3 years 6 months. Physiological parameters (rCBF, rCMRO₂ etc.) in cerebral gray matter, cerebral white matter and basal ganglia were calculated from the single functional images. Any, low density areas appearing in X-ray-CT performed just prior to the PET study were carefully excluded from the analysis. The parameters of moyamoya disease were statistically compared with normal control parameters. Though the value of rCBF was slightly higher in moyamoya disease, this difference was not statistically significant. On the other hand, in moyamoya disease rCBV increased significantly in gray matter, white matter, and basal ganglia. The ratio of CBF to CBV is considered to be the index of perfusion pressure and reciprocal of cerebral mean transit time under the normal autoregulation of CBF. This ratio was calculated and compared with the normal value for each tissue. The ratio was significantly decreased in each tissue in moyamoya disease, indicating the presence of a low perfusion pressure in the moyamoya brain. In general, when the reduction of perfusion pressure becomes profound the decrease in the CBF-to-CBV ratio is followed by an increase in rOEF. In spite of the reduction in the CBF-to-CBV ratio there was no significant increase in rOEF in moyamoya disease. Thus, the cerebral circulation in childhood moyamoya disease of ischemic type was characterized by a mild decrease in perfusion pressure and a prolonged circulation time.     

急性颅内高压时呼气末正压通气对脑氧代谢的影响

目的 观察呼气末正压通气（PEEP）对急性高颅压犬脑氧代谢的影响。方法 8只犬,全麻、机械通气,自体血凝块注入右额叶脑内制成颅内高压模型,静脉滴注脂多糖诱发急性肺损伤,PEEP从0cmH2O开始每次增加3cmH2O水柱,直到18cmH2O,每个水平持续20min,在左侧额顶部用光纤颅内压探头监测颅内压（ICP）的变化,记录平均动脉压（MAP）并计算脑灌注压（CPP）。股动脉、左颈内静脉球部逆行置管采血,行血气分析并计算脑氧摄取（CEO2）和脑动静脉氧含量差（Da-jO2）,分析其与MAP、ICP和CPP的相互关系。结果 随着PEEP的递增,MAP下降,ICP,CPP均有不同程度下降,Da-jO2、CEO2呈上升趋势。血流动力变化与脑氧代谢之间无明显相关性。结论 PEEP通气可改善氧合,但使脑灌注下降,血流动力指标与脑氧代谢指标之间无明显一致性,单用ICP、CPP不能完全判断组织灌注是否充分,有必要监测脑氧代谢,以指导设置PEEP水平。     

Changes in cerebral glucose metabolism with normal aging

The pattern of changes in cerebral glucose metabolism occurring with normal aging has been unclear. Advances in imaging technology, such as improved resolution and anatomical referencing, allow for more precise regional measurement than previously possible. This study explored cerebral glucose metabolism in 17 normal controls ranging in age from 20 to 74 years. High resolution PET scanning, with MRI-based regions of interest correcting for partial volume and atrophy effects, revealed a linear association between advancing age and declining cerebral glucose metabolism. The decline averaged 8% per decade for the whole brain. Changes were most pronounced in limbic structures, and could be implicated in age-associated memory loss.     

Alteration of cerebral ganglioside metabolism in developing Snell dwarf mice

The ganglioside metabolism of the Snell dwarf cerebrum was examined on postnatal days 15 and 20, by monitoring the rate of incorporation of radioactivity into each ganglioside species from tritiated . It was found that the turnover rate of the G_M3 ganglioside was reduced throughout the entire period of development, resulting in retardation of A pathway metabolism which becomes abundant during late cerebral development. In addition, the turnover rate of the G_M4 species, which is considered related to myelin formation, was also found to be reduced throughout the entire period of cerebral development.     

Cerebral blood flow and metabolism in soman-induced convulsions

Regional cerebral blood flow (CBF) and regional cerebral glucose utilization (CGU) were studied by quantitative autoradiographic techniques in rats. Animals were treated either with a toxic dose of soman, an irreversible organophosphorus cholinesterase inhibitor, that produced convulsions or with saline as controls. An increased arterial blood pressure (mean increase = 41% of control) always preceded onset of convulsions. Convulsive activity was associated with an increase of plasma glucose concentration and marked increases over controls of CGU [average of all regions: control = 75 +/- 5 mumol.100 g-1.min-1, n = regions/animals (304/8); seizures = 451 +/- 20 mumol.100 g-1.min-1, n = 190/5] and CBF [average of all regions: control = 135 +/- 6 ml.100 g-1.min-1, n = 190/5; seizures = 619 +/- 29 ml.100 g-1.min-1, n = 190/5). Regional distribution of these effects revealed a greater proportional increase of CBF over CGU in cingulate, motor, and occipital cortex and caudate-putamen. In contrast, a lower proportional increase of CBF over CGU in CA3 region of hippocampus, dentate gyrus, medial thalamus, and substantia nigra was observed, implying the existence of a relative ischemia in these brain areas. These findings may be relevant to the pathogenesis of brain lesions associated with soman-induced convulsions.     

Age-related changes in cerebral blood flow and glucose metabolism in conscious rhesus monkeys

Regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of glucose (rCMRglc) were measured in aged and young monkeys by positron emission tomography (PET). Our purpose was to examine whether the age-related changes observed in the human brain also occur in the monkey brain. Studies were performed on six aged and six young-adult male rhesus monkeys (Macaca mulatta). rCBF and the rCMRglc were serially measured using PET with [(15)O]H(2)O and 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG), respectively. In order to minimize the bias induced by anesthesia, the PET emission scans were performed in the conscious state. ROIs were taken for the cerebellum, hippocampus with adjacent cortex, striatum, occipital cortex, temporal cortex, frontal cortex and cingulate. Group differences and correlations between rCBF and rCMRglc in each group were determined. Aged monkeys had significantly lower rCBF in the cerebellum, hippocampus with the adjacent cortex, striatum, occipital cortex, temporal cortex, frontal cortex, and significantly lower rCMRglc in the cerebellum, hippocampus with the adjacent cortex, striatum, occipital cortex, temporal cortex, frontal cortex and cingulate, compared to young monkeys. There were significant correlations between rCBF and rCMRglc in both the aged and young groups, but no significant difference was found in relationship between the two groups. Age-related changes were observed not only in rCMRglc, but also in rCBF in aged monkeys, while the coupling between rCBF and rCMRglc was maintained even in aged monkeys. These results demonstrated the potential of aged monkeys to serve as an aged human model using PET.     

Acute ethanol administration selectively alters localized cerebral glucose metabolism

The effects of acute ethanol administration on glucose utilization in the CNS of rat were studied using the 2-deoxyglucose technique. Cerebral glucose utilization was determined for 53 brain regions at peak and descending blood ethanol concentrations averaging 14, 26 and 66 mM. Decreased glucose utilization was the predominant finding and was observed in 20% of the regions evaluated, with median raphe, vestibular nucleus, cerebellar vermis, and various structures associated with the auditory system showing the greatest reductions. The only structures that showed increased glucose utilization were the dentate region of the hippocampus and the superior olive, and this was only apparent at a blood ethanol concentration of 14 mM.