In vivo neurobiochemical changes of the posterior cingulate gyrus in patients with Alzheimer’s disease detected by multivoxel proton magnetic resonance spectroscopy

Aim of the work

To study the neurobiochemical changes in patients with Alzheimer’s disease (AD) by multivoxel 1H-MRS.

Materials and methods

Twenty-five patients with probable AD and 12 age- and sex-matched normal controls were subjected to assessment of cognitive functions by the Mini Mental State Examination (MMSE) and imaging with multivoxel 1H-MRS for measuring the NAA/Cho, NAA/Cr, Cho/Cr, MI/NAA and MI/Cr ratios in the posterior cingulate gyrus (PCG) bilaterally.

Results

Patients with AD showed significant decrease in NAA/Cho and NAA/Cr, significant increase in MI/NAA and MI/Cr and non-significant increase in Cho/Cr ratios compared to control. Also, the severity of cognitive impairment was significantly associated with these changes. The NAA/Cho ratio at a cut-off value ?1.14 showed accuracy (94%), the NAA/Cr ratio at a cut-off value ?1.40 showed accuracy (97%), the Cho/Cr ratio at a cut-off value >1.29 showed accuracy (85%), the MI/NAA ratio at a cut-off value >0.60 showed accuracy (98%), and the MI/Cr ratio at a cut-off value >0.83 showed accuracy (97%).

Conclusion

The multi-voxels 1H-MRS of the PCG is sensitive to biochemical changes in AD. The 1H-MRS peak metabolite concentration ratios may be useful as markers for the progression of AD.     

Multivoxel proton magnetic resonance spectroscopy detects thalamic neurochemical metabolic changes in patients with major depressive disorder

Background

Major depressive disorder (MDD) is one of the most commonly encountered psychiatric disorders in daily medical practice. Severity of depression may relate to thalamic neurochemical metabolic changes. Proton magnetic resonance spectroscopy (1H-MRS) can give an idea about the mechanisms that possibly underlie MDD and the response to therapy.

Malignant focal brain lesions. Value of MRS tumour biomarkers in preoperative prediction of grades of malignancy

Purpose

Our aim is to describe the spectrum of proton-MR spectroscopy in malignant focal brain lesions and to detect grade of malignancy using MRS tumor biomarkers.

Materials and methods

87 patients (63 males and 24 females) with focal brain lesion(s) are included in this study. All had a brain tumor recently diagnosed by MRI and had received no previous treatment. They were referred to MRS examination before surgical biopsy and/or resection or radiotherapy.

Results

In malignant brain tumors, average Cho/NAA ratio was 3.3 ± 0.22, Cho/Cr ratio was 2.95 ± 0.21, MI/NAA ratio was 1.5 ± 0.12, MI/Cr was 0.53 ± 0.11 with lower MI levels and higher choline levels in more malignant tumours, lipid/lactate peak was detected in brain metastasis and high grade malignant brain tumors.

Conclusion

Higher Cho/NAA, Cho/Cr and MI/NAA ratios with lower MI/Cr, and high lipid/lactate peak, were most likely to be in high grade malignant brain tumors.     

Feasibility of H-MR Spectroscopy in evaluation of cervical spondylotic myelopathy

Purpose

To assess the diagnostic value of magnetic resonance spectroscopy (MRS) in the evaluation of cervical spinal cord biochemical changes in patients with cervical spondylotic myelopathy (CSM).

Materials and methods

Twenty-four patients with cervical spondylotic myelopathy (patient group) and eleven age matched neurologically free volunteers (control group) underwent magnetic resonance imaging. MRS was assessed for the main metabolites including N-acetylaspartate (NAA), Choline (Cho), Creatine (Cr) and Lactate (Lac). The MRS findings of both groups were compared.

Results

Significant reduction in NAA/Cr ratio of patients with CSM (mean = 1.34 ± 0.09) in comparison to controls (mean = 1.82 ± 0.08). No significant differences in Cho/Cr ratio between both groups. Lactate peak was detected in nine patients while it was not detected in any of the controls. The difference in NAA/Cr ratio between patients with Lac peak and those without Lac peak was insignificant.

Conclusion

MRS is a promising non invasive technique that can help to evaluate metabolic changes of the cervical cord in cervical spondylotic myelopathy even in normally looking-areas.     

Localized 1H-MR Spectroscopy in Moyamoya Disease before and after Revascularization Surgery

Objective

To evaluate, using localized proton magnetic resonance spectroscopy (¹H-MRS), the cerebral metabolic change apparent after revascularization surgery in patients with moyamoya disease.

Materials and Methods

Sixteen children with moyamoya disease and eight age-matched normal controls underwent MR imaging, MR angiography, conventional angiography, and ^99mTc-ECD SPECT. Frontal white matter and the basal ganglia of both hemispheres were subjected to localized ¹H-MRS, and after revascularization surgery, four patients underwent follow-up ¹H-MRS.

Results

Decreased NAA/Cr ratios (1.35±0.14 in patients vs. 1.55±0.24 in controls) and Cho/Cr ratios (0.96±0.13 in patients vs. 1.10±0.11 in controls) were observed in frontal white matter. After revascularization surgery, NAA/Cr and Cho/Cr ratios in this region increased. In the basal ganglia, there is no abnormal metabolic ratios.

Conclusion

Localized 1H-MRS revealed abnormal metabolic change in both hemispheres of children with moyamoya disease. Because of its non-invasive nature, ¹H-MRS is potentially useful for the preoperative evaluation of metabolic abnormalities and their postoperative monitoring.     

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.     

多体素1H - MRS在脑肿瘤强化周围区域中的临床应用

目的探讨多体素1H磁共振波谱(1H-MRS)在颅脑肿瘤强化周围区的代谢物改变特点及其鉴别诊断意义。方法脑肿瘤患者35例,多体素1H-MRS采集NAA、Cho、Cr、Lac、L ip、m I和A la峰,分别计算星形细胞瘤、转移瘤、脑膜瘤的肿瘤强化区、强化周围区和正常参照区域的代谢物浓度,计算不同脑肿瘤、同种脑肿瘤不同区域及高、低级胶质瘤各代谢物比值平均值,比较统计学差异,记录Lac、L ip、m I和A la是否出现。结果肿瘤强化区NAA/Cho、NAA/Cr和Cho/Cr平均值与正常参照区比较均有显著性差异(P<0.05);共出现17例Lac峰、7例L ip峰、6例A la峰和6例m I峰;强化周围区,三者的NAA/Cho、NAA/Cr、NAA/nCr、Cho/NAA值具显著性差异;良、恶性胶质瘤间,NAA/Cho、NAA/nCr、Cho/Cr和Cho/nCho值具有统计学差异(P<0.05)。结论多体素1H-MRS对肿瘤强化周围区域的评价,有助于星形细胞瘤与脑转移瘤、脑膜瘤的鉴别诊断及浸润范围的划定。     

Apparent diffusion coefficient and Magnetic resonance spectroscopy in grading of malignant brain neoplasms

Aim

This work aims to study the role of combined apparent diffusion coefficient (ADC) and Magnetic resonance spectroscopy (MRS) in grading malignant brain neoplasms.

Methods

A prospective study included 40 patients who were evaluated by standard contrast enhanced MRI, diffusion weighted imaging and multivoxel spectroscopy.

Results

Statistically significant difference was found between tumoral ADC values in low grade versus high grade tumors and metastasis and also between the peritumoral ADC values in metastasis versus low and high grade tumors. Statistically significant difference is noticed between tumoral Cho/Cr ratio values in low grade versus high grade tumors and metastasis, and also peritumoral Cho/Cr ratio values in low grade and metastasis versus high grade tumors. Statistically significant difference between tumoral Cho/NAA ratio in low grade versus high grade tumors and metastasis and lastly between peritumoral Cho/NAA ratio in low grade and metastasis versus high grade tumors was found. Lipid and lactate peaks were found frequently in high grade tumors and metastasis.

Conclusion

The combination of calculated ADC values and MR spectroscopy is useful in grading of malignant brain tumors and were more useful together than each on its own.     

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.     

中重度OSAHS患者CPAP治疗前后1H-MRS变化的初步研究

目的：用多体素磁共振波谱(1 H-MRS)探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者持续正压通气(CPAP)治疗前后的变化。方法对25例进行 CPAP 治疗前后的中重度男性 OSAHS 患者及与其性别、年龄相匹配的25例健康对照者的双侧额叶均行头颅多体素1 H-MRS 检查。分别记录额叶各代谢物比值,比较两两之间的差异,并观察有无乳酸(Lac)峰出现。结果治疗前额叶 NAA/Cr、NAA/Cho(2.0212±0.2312和1.6088±0.2571)较健康对照者(2.7268±0.6071和2.4456±0.4375)减低,治疗后额叶 NAA/Cr、NAA/Cho(2.3140±0.3128和2.0164±0.4240)较治疗前(2.0212±0.2312和1.6088±0.2571)升高,治疗后额叶 NAA/Cr、NAA/Cho(2.3140±0.3128和2.0164±0.4240)较健康对照者(2.7268±0.6071和2.4456±0.4375)减低(P <0.01)。治疗前 Cho/Cr(1.2932±0.2615)较健康对照者(1.1292±0.1577)升高(P <0.05)。3组均未检测到 Lac 峰。结论多体素1 H-MRS 能敏感显示 OSAHS 患者 CPAP 治疗前后脑代谢的改变,提供临床疗效及预后评估的影像学依据。     

Fire-Related Post-Traumatic Stress Disorder: Brain 1H-MR Spetroscopic Findings

Objective

To investigate the MR imaging and ¹H-MR spectroscopic findings of acute fire-related post-traumatic stress disorder (PTSD).

Materials and Methods

Sixteen patients (M:F=10:6; mean age, 16 years) with fire-related PTSD underwent MR imaging and ¹H-MR spectroscopy, and for control purposes, the procedures were repeated in eight age-matched normal volunteers. In all patients and controls, the regions of interest where data were acquired at MRS were the basal ganglia (BG), frontal periventricular white matter (FWM), and parietal periventricular white matter (PWM).

Results

In all patients with PTSD, MR images appeared normal. In contrast, MRS showed that in the BG, NAA/Cr ratios were significantly lower in patients than in volunteers. This decrease did not, however, show close correlation with the severity of the neuropsychiatric symptoms. In patients, neither NAA/Cr ratios in FWM nor PWM, nor Cho/Cr ratios in all three regions, were significantly different from those in the control group.

Conclusion

Decreased NAA/Cr ratios in the BG, as seen at ¹H-MRS, might be an early sign of acute fire-related PTSD.     

MRS of brain tumors: Diagrammatic representations and diagnostic approach

Purpose

To evaluate magnetic resonance spectroscopy (MRS) in the assessment of brain tumors and grading brain glioma.

Patients and methods

Retrospective study was done for 42 patients with diagrammatic representations suggested by the author for the assessment of MRS data.

Results

Pathology grading was correlated with metabolic ratios in cases of brain glioma. Ratios higher than 1.5 for either Cho/Cr or Cho/NAA were consistent with tumors and ratios higher than 2 were consistent with high grade glioma or metastases.

Conclusion

MRS can be used to grade cases of brain glioma. Diagrammatic representations and a diagnostic approach were suggested by the author to simplify clinical practice.     

Predicting grade of cerebral gliomas using Myo-inositol/Creatine ratio

Purpose

Our aim was to determine the diagnostic accuracy of MI/Cr ratio in determining the grade of glioma.

Materials and methods

Twenty-two patients (14 males and 8 females), ranging in age from 15–63 years (mean 34.4 years) were prospectively recruited for this study. All had a brain tumor recently diagnosed by MRI and had received no previous treatment, except for steroids. They were referred for MRS examination before surgical biopsy and/or resection or radiotherapy. Ratios for MI/Cr, Cho/Cr, and Cho/NAA were obtained for each lesion and compared with the grade of the lesion.

Results

The levels of MI/Cr were higher (2.14 ± 1.4) in patients with low-grade astrocytoma, and lower in patients with anaplastic astrocytoma (0.39 ± 0.11) and GBM (0.025 ± 0.06). 21 out of the 22 patients were correctly classified using MI/Cr ratio, one patient was misdiagnosed as high grade glioma and the biopsy revealed grade II glioma. The diagnostic accuracy, sensitivity and specificity of MI/Cr ratio for the grading of glioma was 95.4%, 100%, and 92.8%, respectively.

Conclusion

MRS has proven to be an important complementary tool saving the patient from unnecessary biopsy taking when it is conclusive thus altering the treatment planning. This study had demonstrated that MI level and MI/Cr ratio are important in presurgical grading of brain tumors.     

MRS对胼胝体病变的鉴别诊断价值

目的 探讨多体素氢质子磁共振波谱(1H-MRS)对胼胝体病变的鉴别诊断价值.方法 选取17例经临床或病理证实的胼胝体病变患者,其中胼胝体淋巴瘤2例、胼胝体变性4例、胼胝体胶质瘤3例、胼胝体梗死7例、胼胝体多发性硬化1例,研究其病灶MRS特点.结果 2例胼胝体淋巴瘤病灶胆碱(Cho)峰明显升高,肌酸(Cr)及N-乙酰天门冬氨酸(NAA)峰明显降低,并出现高耸的脂质(Lip)峰;4例胼胝体变性患者中2例示Cho/Cr升高,NAA/Cr下降,1例示正常,1例探测到倒置的乳酸(Lac)峰;3例胼胝体胶质瘤病灶NAA峰下降或消失、Cho峰不同程度升高;7例胼胝体梗死均出现明显倒置的Lac峰,NAA不同程度下降;1例多发性硬化患者活动期病灶强化且Cho峰升高,NAA峰降低,并出现倒置的Lac峰,非活动期病灶不强化且MRS基本恢复正常.结论 多体素1H-MRS对胼胝体病变的鉴别诊断有重要的临床应用价值.     

Metabolic changes in the normal ageing brain: consistent findings from short and long echo time proton spectroscopy

Objectives

Sixty three healthy subjects were measured to assess dependence of brain metabolites on age using short- and long echo time spectroscopy in different brain regions.

Material and methods

Younger and elderly humans were measured with long echo time (TE = 135 ms) 3D-MR-spectroscopic imaging (MRSI) (10 subjects) and with ultra-short echo (TE = 11 ms) time 2D-MRSI (7 subjects). In addition, results from single voxel ¹H-spectroscopy (TE = 20 ms) of two cohorts of 46 healthy subjects were retrospectively correlated with age.

Results

3D-MR SI revealed reduced NAA/Cr in the older group in the frontal lobe (−22%; p < 0.01), parietal lobe (−28%; p < 0.01) and semiovale (−9%; p < 0.01) compared to the younger group. Cho/Cr was elevated in the semiovale (+35%; p < 0.01) and in the n. lentiformis (+42%; p < 0.01) in the older group. NAA/Cho was reduced in all regions measured, except the thalamus, in the older group compared to the younger group (from −21 to −49%; p < 0.01). 2D-MRSI revealed decreased total NAA (−3.1% per decade; p < 0.01) and NAA/Cr (−3.8% per decade; p < 0.01), increased total Cho (+3.6% per decade; p < 0.01) and Cho/Cr (+4.6% per decade; p < 0.01) and increased total myo-Inositol (mI, +4.7% per decade; p < 0.01) and mI/Cr (+5.4% per decade; p < 0.01) and decreased NAA/Cho (−8% per decade; p < 0.01) in semiovale WM. Results from single voxel spectroscopy revealed a significantly negative correlation of NAA/Cho in frontal (−13% per decade; p < 0.01) and in temporal lobe (−7.4% per decade; p < 0.01) as well as increased total Cr (10% per decade; p < 0.01) in frontal lobe. Other results from single voxel measurements were not significant, but trends were comparable to that from multivoxel spectroscopy.

Conclusion

Age-related changes measured with long echo time and short echo time 1H-MRS were comparable and cannot, therefore, be caused by different T2 relaxation times in young and old subjects, as suggested previously.     

小儿流行性乙型脑炎磁共振波谱特征及随访研究

目的：探讨磁共振氢质子波谱（1H-MRS）对小儿流行性乙型脑炎预后评价的价值。方法：对17例常规MRI有信号异常的乙脑患儿行1H-MRS扫描,并选择15例同龄健康志愿者对照。病例组在3个月内进行随访并复查MRI,根据随访结果将患者分治愈组和未治愈组,回顾性分析两组患儿首次1H-MRS特征。结果：病灶在T1WI呈斑片状等或稍低信号、T2WI及FLAIR呈稍高或高信号,其中累及灰质核团13例,均呈对称性分布,边界清晰。17例患儿中1H-MRS均见不同高度Lac峰,7例NAA峰有明显下降,2例Cho峰轻度降低,1例出现Cr峰下降,3例出现MI峰。病例组与对照组之间NAA/（Cr＋Cho）值差异有显著性意义（t=5.98,P〈0.05）。根据随访结果,治愈组11例,未治愈组6例,两组NAA/（Cho＋Cr）差异有显著性意义（t=3.45,P〈0.05）。结论：乙脑患儿病变易累及灰质核团,1H-MRS多见Lac双峰,NAA明显下降往往提示患儿病情较重,预后不良。1H-MRS能反映乙脑严重程度并判断预后,是常规MRI有益补充。     

脑胶质瘤周围区的~1H-MRS研究

目的应用多体素氢质子磁共振波谱(1H-MRS)探讨胶质瘤周围区脑代谢改变的特点,评价多体素1H-MRS在胶质瘤周围区的应用价值。方法23例病理证实的脑胶质瘤病人分为低级别组(WHOⅠ～Ⅱ级)13例和高级别组(WHOⅢ～Ⅳ级)10例,所有病例术前均行多体素1H-MRS检查,测量肿瘤实质区、周围区及对侧正常脑组织区代谢产物的相对定量,进行统计学比较。结果多体素1H-MRS显示高级别胶质瘤的周围区与实质区NAA/Cr、Cho/Cr、NAA/Cho值差异有统计学意义(P值均为0.00)。高级别胶质瘤周围区与对侧正常脑组织区NAA/Cr、Cho/Cr、NAA/Cho、Glx/Cr值差异均有统计学意义(P值均为0.00);低级别胶质瘤周围区与实质区NAA/Cr、Cho/Cr、NAA/Cho值差异均有统计学意义(P值均为0.00);低级别胶质瘤周围区与对侧正常脑组织区Cho/Cr、NAA/Cho值差异均有统计学意义(P值分别为0.02、0.00);高级别与低级别胶质瘤实质区NAA/Cr、NAA/Cho、Cho/Cr、Glx/Cr值差异均有统计学意义(P值分别为0.00、0.00、0.03、0.00);高级别与低级别胶质瘤周...     

Neurochemical-structural changes evaluation of brain in patients with obstructive sleep apnea syndrome

Purpose

To evaluate neurochemical and structural changes in the patients with newly diagnosed obstructive sleep apnea syndrome (OSAS) by MR spectroscopy (MRS), T2 relaxometry, and diffusion weighted imaging (DWI).

Material and methods

Following the acquisition of routine cranial MR, MRS, T2 relaxometry, and DWI images; spectroscopic metabolite ratios and DWI–T2 relaxometry findings of the thalami, hippocampi, frontal white matter (FWM) and frontal cortex of 24 OSAS patients and 9 controls were statistically compared. The relationship between two groups was evaluated with Mann–Whitney test.

Results

Spectroscopic measurements in the frontal cortex and frontal white matter of the OSAS patients revealed significantly lower NAA/Cr ratios than those of the control group (P = 0.004 and P = 0.006, respectively). The measurements in the frontal white matter of the OSAS patients exhibited significantly lower NAA/Cho ratios compared with those of the control group (P = 0.005). Thalamic Cho/Cr ratios of the patient group were significantly higher than those of the control group (P = 0.002). In terms of the ADC–T2 relaxometry values, there was no significant relationship between the patient and the control groups (P > 0.05).

Conclusion

MRS is a useful and non-invasive modality in showing neurochemical changes in various regions of the brain but our data does not show any change on diffusion weighting or T2 quantification in the OSAS group. DWI and T2 relaxometry appear to be not effective techniques to evaluate the brain structural changes of the patients with newly diagnosed OSAS.     

皮质下动脉硬化性脑病的1H-MRS初步研究

目的 应用2D多体素1H质子磁共振波谱成像(1H-MRS)检查皮质下动脉硬化性脑病(BD)患者,分析其代谢产物特点及变化规律.方法 对经临床诊断的20例BD患者和20名健康老年人行常规MRI和二维1 H-MRS检查,测量BD组常规MRI表现阳性病灶区、BD组表现正常脑白质区及对照组正常脑白质3组NAA/Cr、Cho/Cr值,并进行统计学分析;观察Lac峰的变化情况.结果 BD病灶区NAA/Cr值、Cho/Cr值降低,与对照组脑白质差异均有统计学意义(P＜0.05);BD正常脑白质区NAA/Cr值与正常对照组相比有所降低,且差异有统计学意义(P＜0.05),BD正常脑白质区Cho/Cr值较对照组脑白质相比差异没有统计学意义(P＞0.05);BD病灶区全部出现Lac峰,BD正常脑白质区出现Lac峰12例.结论 1H-MRS检查能够反映BD代谢特点及变化规律;1H-MRS中的NAA/Cr可以显示常规MRI检查表现正常的脑白质微代谢改变.     

脑梗死~1H磁共振波谱研究初探

目的 :初步探讨脑部1H磁共振波谱分析对脑梗死治疗和预后的价值。材料和方法 :22例脑梗死患者行32次常规MRI和1H -MRS检查。MRS检查采用PRESS序列 ,对病变区和对侧半球相应部位进行测量。主要观察的代谢物为NAA ,Cr,Cho和Lac。病灶NAA ,Cr和Cho的相对值以病侧和对侧各代谢物共振峰谱线下积分面积的比值来表示。病灶Lac的相对值则以病灶Lac和对侧Cr共振峰高度的比值来表示。结果 :超急性期脑梗死NAA下降 ,并出现Lac峰 ,而Cr和Cho无明显变化。随病情进展NAA进一步减少 ,以至消失 ;Lac峰仍持续存在 ,至慢性晚期逐渐消失 ;Cr和Cho也逐渐减少 ,但Cho减少的程度颇多变异。结论 :1H -MRS所提供的脑梗死区代谢变化对脑梗死救治时间窗口的预测可能有一定帮助。