Magnetization transfer imaging and magnetic resonance spectroscopy of normal-appearing white matter in late-life major depression

PURPOSE: To examine the relationships between the damaged macromolecular pool seen on magnetization transfer (MT) imaging and cerebral metabolic changes recorded by magnetic resonance spectroscopy (MRS), in frontal white and gray matter regions of late-life MDD patients. MATERIALS AND METHODS: MT imaging and MRS were performed on eight patients with late-life MDD and eight age-matched healthy controls. MT ratios were calculated using the on-resonance and off-resonance images. Correlations were computed between MT ratios and the ratios of several metabolites, including choline (Cho), myo-inositol (mI), N-acetylaspartate (NAA), and N-acetylaspartylglutamate (NAAG), to creatine (Cr). RESULTS: Statistically significant correlations were found in white matter between the MT ratios and mI/Cr (r = -0.90, N = 7, P = 0.016), and between the MT ratios and (NAA + NAAG)/Cr (r = -0.89, N = 8, P = 0.007). No significant correlations were found in gray matter or between the MT ratios and NAA/Cr or Cho/Cr in white matter. CONCLUSION: Changes in the white matter macromolecular protein pool, observed as reduced MT ratios, may be related to changes in the mI and the total NAA pools. These findings may have implications for the pathophysiology of late-life major depression.     

3.0T ~1H-MRS在脑内高级别星形细胞瘤及单发转移瘤鉴别诊断中的价值

目的:探讨多体素氢质子磁共振波谱(1 H-MRS)对脑高级别星形细胞瘤、单发脑转移瘤的鉴别诊断价值。方法:收集经手术、活检病理证实的颅脑肿瘤患者37例,其中高级别星形细胞瘤(Ⅲ~Ⅳ级)17例(间变性星形细胞瘤5例,胶质母细胞瘤12例),脑单发转移瘤20例。37例行颅脑常规MRI检查及多体素1 H-MRS分析,分析肿瘤实质强化区、强化边缘区、对侧相应正常区域脑组织的生化代谢物及其比值,并进行对照。结果:1脑高级别星形细胞瘤、脑转移瘤1 H-MRS与对侧相应正常区域对比均表现为Cho峰升高,NAA、Cr峰下降。12例胶质母细胞瘤中,显示Lip峰者11例。20例脑转移瘤中,11例见Lac峰升高,9例Lip峰升高。2高级别星形细胞瘤肿瘤实体区的Cho/NAA明显高于脑转移瘤(P0.05);高级别星形细胞瘤瘤周水肿的Cho/Cr、Cho/NAA明显高于脑转移瘤(P0.05)。结论:3.0T1 H-MRS分析对高级别星形细胞瘤、脑单发转移瘤的诊断和鉴别诊断有重要价值,可作为一种非损伤性的鉴别手段;肿瘤瘤周水肿带的波谱更有利于胶质瘤与转移瘤的鉴别。     

~1H-MRS在胶质母细胞瘤周围区的应用研究

目的:评价2D多体素磁共振氢质子波谱成像技术(1 H-MRS)在胶质母细胞瘤周围区中的应用价值。方法:对30例胶质母细胞瘤患者行常规MRI及1 H-MRS检查,所有患者均行增强扫描。测量肿瘤周围区(包括水肿区及瘤周显示正常区域)的Cho/Cr、Cho/NAA、NAA/Cr的比值,并且计算瘤周显示正常区域的NAA/nCr的比值,将以上值与对侧正常区域的相应比值进行两样本配对t检验,分析其差异是否有统计学意义。结果:肿瘤周围水肿区及瘤周显示正常区的Cho/Cr、Cho/NAA的比值较对侧明显升高,差异有统计学意义(P<0.05)。肿瘤周围水肿区的NAA/Cr值较对侧降低且差异有统计学意义(P<0.05);肿瘤周围显示正常区的NAA/Cr值较对侧亦有降低,但差异无统计学意义(P>0.05),瘤周显示正常区NAA/nCr值较对侧明显降低,差异有统计学意义(P<0.05)。结论:2D多体素1 H-MRS成像技术对肿瘤周围区代谢物变化的检测可为推断胶质母细胞瘤瘤周区肿瘤细胞的浸润范围提供依据。     

Relapsing-remitting multiple sclerosis: metabolic abnormality in nonenhancing lesions and normal-appearing white matter at MR imaging: initial experience

PURPOSE: To quantify, with three-dimensional proton magnetic resonance (MR) spectroscopy, metabolic characteristics of normal-appearing white matter and nonenhancing lesions in patients with relapsing-remitting multiple sclerosis (MS). MATERIALS AND METHODS: Institutional review board approval and informed patient consent were obtained. Nine patients with relapsing-remitting MS (six women, three men) and nine age-matched control subjects (seven women, two men) were studied with T1- and T2-weighted MR imaging and three-dimensional proton MR spectroscopy at spatial resolution less than a cubic centimeter. Absolute N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) levels were obtained from 171 voxels: 66 from lesions on T2-weighted MR images (43 hypointense and 23 isointense on T1-weighted MR images), 31 from normal-appearing white matter, and 74 from analogous normal white matter regions on images in control subjects. RESULTS: Mean NAA level in hypointense lesions (5.30 mmol/L +/- 2.27 [standard deviation]) was significantly lower (P < or = .05) than that in isointense lesions (7.82 mmol/L +/- 2.28), normal-appearing white matter (7.37 mmol/L +/- 1.71), and normal white matter in control subjects (8.89 mmol/L +/- 1.54). Cho (1.79 mmol/L +/- 0.65) and Cr (5.64 mmol/L +/- 1.50) levels in isointense lesions were indistinguishable from those in normal-appearing white matter (1.74 mmol/L +/- 0.46 and 4.99 mmol/L +/- 0.97, respectively) but were significantly higher (Cho, 20%; Cr, 24%) than those in normal white matter in control subjects (1.44 mmol/L +/- 0.40 and 4.30 mmol/L +/- 1.32, respectively). NAA, Cho, and Cr levels in normal-appearing white matter were significantly different than those in normal white matter in control subjects (NAA, 20% lower; Cho, 14% higher; and Cr, 17% higher). CONCLUSION: Abnormal metabolic activity persists in all MS tissue types. Increased Cr and Cho levels suggest (a) ongoing gliosis and attempted remyelination in isointense lesions on T1-weighted MR images and (b) membrane turnover (de- and remyelination), in addition to increased cellularity (gliosis, inflammation) in normal-appearing white matter.     

Brain metabolite changes on proton magnetic resonance spectroscopy in children with poorly controlled type 1 diabetes mellitus

The metabolite changes in the brains of children with poorly controlled type 1 diabetes mellitus (DM) were investigated by proton magnetic resonance spectroscopy (MRS). A total of 30 subjects and 14 age-matched healthy volunteers underwent single-voxel MRS (TE: 136). The duration of disease, medication, presence of hypoglycaemia episodes and the level of haemoglobin A1C (HbA1C) in the patients were noted. Voxels were placed in the pons, left basal ganglion (LBG) and left posterior parietal white matter (PPWM). N-acetylaspartate (NAA)/creatinine (Cr) and choline (Cho)/Cr ratios were calculated. The average HbA1c level was 11.9±3.4 (8.2–19.4). The average number of keto-acidosis episodes was 1.9±2.2 (0–9) and the average number of daily insulin injections was 2.8±0.97 (2–4). MRS revealed lower NAA/Cr and Cho/Cr ratios in the pons and lower NAA/Cr ratio in the PPWM of patients with DM than in control subjects. No significant correlation was observed between the number of hypoglycaemia episodes and metabolite ratios. Metabolic abnormalities have been observed by MRS in the brain of poorly controlled type 1 DM children. These metabolic changes, in particular in the pons region, include a decrease in NAA, indicating neuronal loss or functional impairment, and likely explanations for a decrease in Cho may be dynamic changes in membrane lipids and/or decreased membrane turnover.     

海马硬化MR质子波谱分析与MRI的对比研究

目的　评价MR质子波谱分析 (1HMRS)和MRI对海马硬化的诊断价值。方法　对 8例病理证实的海马硬化病人和 8例健康志愿者分别进行1HMRS和MRI海马体积定量研究。通过计算峰下面积 ,对代谢产物氮 乙酰天门冬氨酸 (NAA)、肌酸 (Cr)及胆碱复合物 (Cho)的浓度进行定量并观察NAA/Cr、NAA/ (Cr Cho)及Cho/Cr各参数的变化 ,同时用右侧海马体积和左侧海马体积差值(DHF)的方法分析形态学的异常。结果　病变组病侧NAA/Cr、NAA/ (Cr Cho)及Cho/Cr值分别为0 5 5、1 77及 1 38,对照组分别为 0 77、1 38及 1 0 6。海马硬化病人NAA/Cr和NAA/ (Cr Cho)值下降 ,统计学上差异有显著性意义 (t值分别为 2 15和 4 83,P值均 <0 0 5 ) ,Cho/Cr值升高 ,统计学上差异有显著性意义 (t值为 2 34 ,P <0 0 5 )。根据NAA/ (Cr Cho)值的不对称降低可对 6例病人进行定侧诊断 ,其中错误 1例 ;根据DHF值的变化可诊断海马萎缩 2例。所有病例均经手术病理证实为海马硬化 ,病变程度与NAA/ (Cr Cho)值的降低相一致。NAA/ (Cr Cho)减低与癫痫发作次数无相关性 (r=- 0 134 ,P >0 0 5 )。结论　1HMRS能够早期发现海马硬化。1HMRS和MRI互相补充有利于海马硬化的术前诊断。     

常规MRI阴性HIV感染者无神经症状期脑1H-MRS分析

目的探讨常规MRI阴性人类获得性免疫缺陷病毒(HIV)感染者无神经症状期脑氢质子磁共振波谱(1H-MRS)特点。资料与方法搜集无神经症状期HIV感染者28例,HIV阴性健康自愿者30名,行MRI平扫、点分辨波谱(PRESS)1H-MRS扫描。测定脑皮质、深部核团及白质区N-乙酰天门冬氨酸(NAA)、胆碱化合物(Cho)、肌酸(Cr)峰下面积;计算NAA/Cr、Cho/Cr、NAA/Cho、(NAA+Cho)/Cr及(Cho+Cr)/NAA值。结果无神经症状期HIV感染者脑皮质、深部核团及白质NAA/Cr值均降低,(Cho+Cr)/NAA值升高,Cho/Cr值无明显变化。额上回皮质NAA/Cr、NAA/Cho、(Cho+Cr)/NAA值,额上回白质NAA/Cr、(NAA+Cho)/Cr、(Cho+Cr)/NAA值,顶叶白质NAA/Cho、(Cho+Cr)/NAA值差异有统计学意义(P<0.05)。结论在HIV感染无神经症状期,常规MRS阴性时,1H-MRS可以检测到脑早期代谢异常。额上回皮质、尾状核头部、额上回、顶叶白质NAA/Cr、NAA/Cho、(Cho+Cr)/NAA值有明显变化。     

Proton MR spectroscopic imaging in multiple sclerosis

We studied 24 patients with multiple sclerosis (MS) by proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the neurochemical pathology of the white-matter lesions (WML) and normal-appearing white matter (NAWM). Our 1H-MRSI technique allowed simultaneous measurement of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) signal intensities from four 15-mm slices divided into 0.84 ml single-volume elements. In WML we found significantly lower NAA/Cr and NAA/Cho ratios and a significantly higher Cho/Cr ratio than in NAWM or control white matter. In NAWM, NAA/Cr and Cho/Cr were significantly lower than in control white matter. 1H-MRSI was compatible with damage to myelin in WML, and with axonal damage and/or dysfunction in WML and NAWM. These findings extend data on involvement of NAWM in MS beyond the abnormalities visible on MRI.     

Cerebral gliomas: prospective comparison of multivoxel 2D chemical-shift imaging proton MR spectroscopy,echoplanar perfusion and diffusion-weighted MRI

Developments in MRI have made it possible to use diffusion-weighted MRI, perfusion MRI and proton MR spectroscopy (MRS) to study lesions in the brain. We evaluated whether these techniques provide useful, complementary information for grading gliomas, in comparison with conventional MRI. We studied 17 patients with histologically verified gliomas, adding multivoxel proton MRS, echoplanar diffusion and perfusion MRI the a routine MRI examination. The maximum relative cerebral blood volume (CBV), minimum apparent diffusion coefficient (ADC) and metabolic peak area ratios in proton MRS were calculated in solid parts of tumours on the same slice from each imaging data set. The mean minimum ADC of the 13 high-grade gliomas (0.92+/-0.27 x 10(-3) mm(2)/s) was lower than that of the four low-grade gliomas (1.28+/-0.15 x 10(-3) mm(2)/s) ( P<0.05). Means of maximum choline (Cho)/N-acetylaspartate (NAA), Cho/creatine (Cr), Cho/Cr in normal brain (Cr-n) and minimum NAA/Cr ratios were 5.90+/-2.62, 4.73+/-2.22, 2.66+/-0.68 and 0.40+/-0.06, respectively, in the high-grade gliomas, and 1.65+/-1.37, 1.84+/-1.20, 1.61+/-1.29 and 1.65+/-1.61, respectively, in the low-grade gliomas. Significant differences were found on spectroscopy between the high- and low-grade gliomas ( P<0.05). Mean maximum relative CBV in the high-grade gliomas (6.10+/-3.98) was higher than in the low-grade gliomas (1.74+/-0.57) ( P<0.05). Echoplanar diffusion, perfusion MRI and multivoxel proton MRS can offer diagnostic information, not available with conventional MRI, in the assessment of glioma grade.     

儿童型肾上腺脑白质营养不良的2D-1H MRSI和DTI初步应用

目的探讨2D-MRSI和DTI在儿童型肾上腺脑白质营养不良的综合应用价值.方法对3例儿童型肾上腺脑白质营养不良患儿行2D-MRSI、DTI和常规MRI检查,比较病变区域代谢物NAA/Cho、NAA/Cr和Cho/Cr比值与ADC和FA的关系,以及它们与T2WI信号强度的相关性;测量常规MRI阴性的ALD额顶叶白质的ADC和FA值有无异常.结果病变T2WI信号强度与NAA/Cho比值和FA负相关,与ADC正相关,即T2WI信号越高,NAA/Cho越低、ADC越高及FA越低,且具有从外到内的层次性.各种代谢物比值以NAA/Cho 比值与ADC和FA相关最密切.DTI不能发现常规MRI阴性的ALD白质病变.结论 MRSI和DTI与常规MRI表现具有一定的相关性,2D-MRSI和DTI可为儿童型肾上腺脑白质营养不良诊断提供更多的信息.     

Proton MR spectroscopy in neuroborreliosis: a preliminary study

We report results of a magnetic resonance spectroscopy (MRS) study in 12 patients with neuroborreliosis. We used a PRESS sequence, placing an 8 cm³ voxel in normal-appearing white matter of the frontal lobe. Peaks indicating N-acetylaspartate (NAA), choline (Cho), creatine (Cr), myo-inositol (mI), lipids (Lip) and lactate (Lac) were identified and ratios of NAA/Cr, Cho/Cr, mI/Cr, Lip/Cr, Lac/Cr calculated. Significant increases in Cho/Cr and Lip/Cr were noted. No abnormality was found in mean NAA/Cr and Lac/Cr, but in four patients there was a decreased NAA peak; mI/Cr ratio was slightly increased. Although the spectroscopic profile in patients with neuroborreliosis seems to be nonspecific, MRS might be useful for assessing tissue damage of the central nervous system.     

小儿正常小脑半球组织~1H-MRS研究

目的:测定和计算0～7岁小儿正常小脑半球组织代谢物比值,并观察各比值随年龄变化规律。方法:应用多体素2D1H-MRS点分辨波谱(PRESS)序列测定70例0～7岁小儿正常小脑半球组织的双侧灰质及白质区代谢物浓度,按年龄分为0-1岁,1-2岁,2-3岁,3-5岁,5-7岁五组,计算和分析NAA/Cr、Cho/Cr、NAA/Cho的比值。结果:正常小脑灰质区在各年龄组间NAA/Cho(P=0.0143)和NAA/Cr(P=0.0050);白质区的NAA/Cho和NAA/Cr均P<0.001;灰质和白质区的Cho/Cr(P=0.1195,P>0.05);灰质和白质区NAA/Cho值与年龄呈正相关(P<0.001,P<0.0001);NAA/Cr值与年龄呈正相关(P=0.0004,P<0.0001);灰质区Cho/Cr与年龄呈负相关(P=0.038),白质区与年龄呈负相关(P=0.568>0.05)。结论:0～7岁小儿正常小脑半球灰、白质的代谢物比值在不同年龄组会不同,灰质和白质区NAA/Cho、NAA/Cr值随年龄增长逐渐升高,而灰质区Cho/Cr值逐渐减小,白质区无明显变化,临床上应用MRS要考虑其年龄和部位的因素。     

磁共振质子波谱在颞叶癫痫诊断中的应用

目的　评价磁共振质子波谱 (1HMRS)诊断颞叶癫痫的价值。方法　对 30例颞叶癫痫患者和 30例健康志愿者用 2 0T场强的MR成像系统分别进行双侧颞叶的质子波谱采集 ,定量分析N 乙酰天门冬氨酸 (NAA)、肌酸 (Cr)和胆碱复合物 (Cho)等代谢产物的变化。结果　癫痫病人NAA峰降低。以NAA/ (Cr Cho)值为判断标准 ,2 5例病人可以定侧诊断 ,敏感性 83% ,并发现 14例双侧病变 ,占 47%。结论　1HMRS可无创性探测脑组织内生化改变 ,对癫痫灶的定侧诊断具有很高的价值     

Differentiation between brain tumor recurrence and radiation injury using MR spectroscopy

OBJECTIVE: The purpose of our study was to explore the feasibility and utility of 2D chemical shift imaging (CSI) MR spectroscopy in the evaluation of new areas of contrast enhancement at the site of a previously treated brain neoplasm. MATERIALS AND METHODS: Two-dimensional CSI (point-resolved spectroscopy sequence [PRESS]; TR/TE, 1,500/144) was performed in 29 consecutive patients (4-54 years old; mean age, 34 years) who had a new contrast-enhancing lesion in the vicinity of a previously diagnosed and treated brain neoplasm. Clinical and imaging follow-up, and histopathology in 16 patients, were used as indicators of the identity of a lesion. RESULTS: Diagnostic-quality spectra were obtained in 97% of the patients. The Cho/Cr (choline/creatine) and Cho/NAA (choline/N-acetyl aspartate) ratios were significantly higher, and the NAA/Cr ratios significantly lower, in tumor than in radiation injury (all three differences, p < 0.0001). The Cho/Cr and Cho/NAA ratios were significantly higher in radiation injury than in normal-appearing white matter (p < 0.0003 and p < 0.0001, respectively), whereas NAA/Cr ratios were not different (p = 0.075). Mean Cho/Cr ratios were 2.52 for tumor, 1.57 for radiation injury, and 1.14 for normal-appearing white matter. Mean Cho/NAA ratios were 3.48, 1.31, 0.79, and mean NAA/Cr ratios were 0.79, 1.22, and 1.38, respectively. When values greater than 1.8 for either Cho/Cr or Cho/NAA ratios were considered evidence of tumor, 27 of 28 patients could be correctly classified. CONCLUSION: Two-dimensional CSI MR spectroscopy can differentiate tumor from radiation injury in patients with recurrent contrast-enhancing intracranial lesions. In these lesions, the Cho/NAA and Cho/Cr ratios may be the best numeric discriminators.     

Early- and late-state subacute sclerosing panencephalitis: chemical shift imaging and single-voxel MR spectroscopy

BACKGROUND AND PURPOSE: Subacute sclerosing panencephalitis (SSPE) is a rare, progressive, inflammatory neurodegenerative disease. Our aim was to determine the metabolic abnormalities of brain in early- and late-stage SSPE by using MR spectroscopy and to assess areas of involvement in the early stages when MR imaging findings were normal. METHODS: Children with stage II (n = 3) or III (n = 3) SSPE and 10 healthy, age-matched children underwent MR imaging, multivoxel MR spectroscopy, and short-echo single-voxel MR spectroscopy (SVS). Areas of involvement in the brain were determined with chemical shift imaging. For SVS, 2 x 2 x 2-cm voxels were placed in the frontal subcortical white matter (FSWM) and parieto-occipital white matter (POWM). N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (Ins)/Cr, and NAA/Cho ratios were calculated. RESULTS: Comparisons of NAA/Cr, Cho/Cr, Ins/Cr and NAA/Cho ratios between patients and control subjects showed significant differences in FSWM and POWM (P <.01). In patients with SSPE, NAA/Cr ratios in POWM were significantly less than those in FSWM (P <.01). NAA/Cr ratios in patients with stage II SSPE and those in the control group were not significantly different; this may reflect the absence of neuronal loss. Decreased NAA/Cr, increased Cho/Cr and Ins/Cr ratios, and increased lactate and lipid peaks were found in patients with stage III SSPE. CONCLUSION: MR spectroscopy showed findings suggestive of inflammation in stage II and findings of demyelination, gliosis, cellular necrosis, and anaerobic metabolism in stage III. MR spectroscopy could be a promising technique for early diagnosis and treatment planning in cases of SSPE.     

Evaluation of metabolic changes within the normal appearing gray and white matters in neurologically asymptomatic HIV-1-positive and HCV-positive patients: Magnetic resonance spectroscopy and immunologic correlation

Objective

The aim of the study was to evaluate early metabolic changes using proton MR spectroscopy (MRS) in asymptomatic HIV-1-positive and HCV-positive patients without abnormalities in the structural MR examination.

Methods

Sixty-five asymptomatic patients: 21 HIV-1-positive naive, 20 HIV-1-positive with combination antiretroviral therapy (cART), 9 HIV-1/HCV-positive naive, 15 HCV-positive naive and 18 normal subjects were enrolled in the study. The MRS examinations were performed with a 1.5 T MR scanner. Voxels were located in the following regions: posterior cingulate gyrus (PCG), anterior cingulate gyrus (ACG), parietal white matter (PWM), left basal ganglia (BG) and frontal white matter (FWM). The NAA/Cr, Cho/Cr, mI/Cr ratios and correlations of MRS measurements with the immunologic data were analyzed.

Results

There was a significant decrease (p < 0.05) of the NAA/Cr ratios in PCG, ACG and PWM regions in HIV-1-positive cART treated patients compared to the normal subjects. The significantly decreased NAA/Cr ratios in PWM and FWM were observed in HCV infected patients. The subjects with HIV-1/HCV co-infection revealed significantly lower NAA/Cr ratios in the ACG area. Other metabolite ratios in all analyzed regions, as well as the NAA/Cr ratios in BG showed no significant differences. The decrease of CD4n T cell count was associated with the decease of the NAA/Cr ratio in the PCG area and the increase of Cho/Cr ratio in the FWM region.

Conclusions

The metabolic changes – reduction of NAA/Cr ratios are most pronounced in HIV-1-positive patients using cART. The low CD4n T cell count is a risk factor for neurocognitive impairment in HIV-1-positive patients.     

Proton MRS of Gadolinium-enhancing MS Plaques and Metabolic Changes in Normal-Appearing White Matter

Localized short echo time (TE = 20 ms), stimulated echo acquisition mode, and double spin echo (TE = 135 ms) proton spectroscopy were performed in clearly defined, acute Gadolinium (Gd)-enhancing multiple sclerosis (MS) plaques of 22 patients with clinically definite MS. The resonances of N-acetylated metabolites (NA), creatine/phosphocreatine (Cr), choline-containing compounds (Cho), glycine/myo-inositol (Ino), and lactate were evaluated. The ratios of NA/Cr and NA/Cho were significantly decreased, Cho/Cr increased, and Ino/Cr remained unchanged. No marker peaks or elevated lactate levels were found. The measured metabolic changes were practically independent of the relative plaque size within the volume of interest (8 ml). Thus, the spectral changes measured with ¹H MRS in acute Gd-enhancing MS plaques originate not only from the lesion as depicted by MRI, but also from the surrounding normal-appearing white matter.     

颅脑爆震伤后兔脑内代谢变化的磁共振波谱研究

目的 利用磁共振波谱技术探讨颅脑爆震伤后不同时间段脑局部代谢变化.方法 新西兰大白兔45只采用随机数字表法分为对照组(10只)和创伤组(35只),采用600 mgTNT当量纸雷管在创伤组兔脑上方约6.5 cm垂直距离爆炸,于伤后1,6,12,24 h、3,7,14 d用磁共振波谱技术观测动物存活情况,并检测脑损伤区病理及磁共振波谱表现,观察乙酰天门冬氨酸(N-acetylaspartate,NAA)/肌酸(creatine,Cr)、胆碱(choline,Cho)/Cr在爆震伤后随时间发展的演变过程.结果 创伤组兔存活时间在7 d以上,病理及常规MRI示脑挫伤病灶;NAA/Cr均值在损伤后1 h明显下降,持续至伤后24 h,24 h后义上升,7 d后再次下降.Cho/Cr均值在损伤1 h后即明显升高,12 h后下降,3 d后义逐渐升高.结论 磁共振波谱技术可反映兔颅脑爆炸伤不同时间段局部组织的代谢变化,为了解爆雀伤后局部组织变化情况及判断组织损伤类型提供理论依据.

Abstract：

Objective To evaluate the regional cerebral metabolic changes in different episodes by magnetic resonance spectroscopy (MRS) after explosive brain injury in rabbits. Methods Fortyfive New Zealand white rabbits were randomly divided into eight groups, ie, normal control group( 10 rabbits) and trauma group (35 rabbits). The explosive injury in trauma group was induced by explosion of 600 mg TNT equivalent of paper detonators at 6.5 cm above the rabbit brain. The rabbits in trauma group was divided into 1,6, 12, 24 hours, 3, 7, 14 days subgroups (6 rabbits per group). The survival rate was observed at different time points after explosive injury. The MRS was used to detect the regional cerebral metabolic changes including N-acetylaspartate (NAA)/creatine (Cr) ratio and choline(Cho)/Cr ratio as well as evolution of blast injuries over time. Results The rabbits survived for overseven days in the trauma groups, with typical brain contusion manifested by pathological and conventional MRI. Compared with the normal control group, the NAA/Cr ratio was markedly decreased at one hour after injury, slightly rose again at 24 hours and fell again after seven days. The Cho/Cr ratio was markedly increased at one hour after injury, slightly fell again at 12 hours and rose again at three days after injury.Conclusions MRS can manifest the regional cerebral metabolic changes of rabbits with explosive injury at different time points and hence provide a theoretical basis for understanding the local tissue changes and determining the type of tissue damage after blast injury.     

急性颈髓创伤MRS

目的探讨MR质谱(1H-MRS)与MRI对急性颈髓损伤的诊断价值.材料和方法对19例急性颈髓损伤病人行MRI与1H-MRS检查,根据MRI表现与临床神经功能分组并计算氮-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)、乳酸(Lac)波峰面积,分析NAA/Cho、NAA/Cr、Cr/Cho、Lac/Cho各值变化,并取9例健康者作对照.结果颈髓完全性损伤组NAA/Cho、NAA/Cr、Cr/Cho、Lac/Cho各值为0.4l、0.4l、1.08、4.2l,不完全损伤组为0.96、0.90、1.05、2.44,对照组为1.1、1.23、1.05、1.3.颈髓完全损伤组与对照组比NAA/Cho、NAA/Cr值降低,Lac/Cho值升高(p＜0.01),不完全损伤组仅Lac/Cho值升高(p＜0.05).颈髓损伤不同程度中,完全损伤组较不完全损伤组中NAA/Cho、NAA/Cr显著减低(p＜0.05).结论1H-MRS可定量测定创区颈髓相关代谢介质的变化,从代谢水平反映颈髓损伤的不同程度,MRI结合1H-MRS有利于颈髓损伤评价.     

急性一氧化碳中毒迟发脑病的磁共振波谱特征及其临床意义

目的 研究急性一氧化碳中毒迟发脑病(delayed encephalopathy following acute carbon monoxide poisoning,DEACOP)患者的质子磁共振波谱(1H magnetic resonance spectroscopy,1H MRS)特征及临床意义.方法 对38例DEACOP患者和30例正常志愿者分别进行常规核磁及质子磁共振波谱检查,对比分析DEACOP患者与正常志愿者的额叶、脑室旁、枕叶的N-乙酰天门冬氨酸(NAA)、肌酸/磷酸肌酸(Cr)、含胆碱代谢物(Cho)含量的变化,对以Cr为参照的代谢产物比值(Cho/Cr,Cho/NAA,NAA/Cr)进行比较,并分析NAA/Cr、Cho/Cr、Cho/NAA与患者简易智能状态检查量表(MMSE)和患者日常生活能力量表(ADL)的相关性.结果 获取的DEACOP组患者波谱数据显示不同部位的NAA/Cr同对照组比较降低,差异有统计学意义(P＜0.01),Cho/Cr、Cho/NAA同对照组比较增高,差异有统计学意义(P＜0.01);Cho/Cr与MMSE、ADL评分呈明显负相关,Cho/NAA与MMSE、ADL评分呈明显负相关,NAA/Cr与MMSE、ADL评分呈明显正相关.中、重度DEACOP患者NAA/Cr同轻度患者比较降低,差异有统计学意义(P＜0.05),Cho/Cr、Cho/NAA同对照组比较增高,差异有统计学意义(P＜0.05).结论 通过1H MRS检测DEACOP患者脑部病灶的代谢异常可显示神经元损伤程度,代谢物比值异常变化提示预后不佳.

Abstract：

Objective To study the characteristics of proton magnetic resonance spectroscopy (1H magnetic resonance spectroscopy, 1H MRS) in patients with delayed encephalopathy following acute carbon monoxide poisoning (DEACOP) and its significance in the early diagnosis of the disease. Methods MRI and 1H MRS were performed in 38 DEACOP patients and 30 healthy volunteers. The ratios of N-acetylaspartate ( NAA), Creatine ( Cr), Choline (Cho) peaks were measured in each volume of interest, and the correlation of Activity of Daily Living Scale (ADL) and Mini-Mental State Examination (MMSE) with NAA/Cr, Cho/Cr,Cho/NAA were analyzed. Results Compared with those of the control group, the NAA/Cr ratio in different parts decreased with very significant statistical differences ( P ＜ 0. 01 ), while Cho/Cr and Cho/NAA ratio increased also with very significant statistical difference ( P ＜ 0. 01 ). Negative correlation was found in the assessment scores between Cho/Cr and MMSE, ADL. Cho/NAA was also negatively correlated in the assessment scores with MMSE and ADL, and NAA/Cr was positively correlated in the assessment scores with MMSE and ADL. The NAA/Cr ratio in moderate and serious DEACOP patients decreased, when it was compared with that of the mild DEACOP patients, with statistical differences (P ＜ 0. 05 ). Cho/Cr and Cho/NAA ratio increased, when it was compared with that of the control group, with statistical differences ( P ＜0. 05). Conclusions 11 MRS could detect metabolic abnormalities in DEACOP patients with brain lesion.Abnormal changes in the ratio of metabolites might indicate poor prognosis.