1 H-MRS对低级别和高级别脑胶质瘤鉴别诊断的作用及病理级别相关性的研究

目的 分析脑胶质瘤的氢质子磁共振波谱（proton magnetic resonance spectroscopy,^1H—MRS）表现及其临床意义;探讨脑胶质瘤的^1H—MRS特点与其病理级别相关性。资料与方法 搜集经临床手术、病理证实的脑胶质瘤36例,按照WHO诊断标准分成两组：低级别脑胶质瘤组、高级别脑胶质瘤组。所有患者在术前行^1H—MRS检查。均在MR非增强成像的基础上获得。使用Siemens Sonata 1．5T超导磁共振扫描仪,多体素扫描,点分辨表面线圈法,检测不同区域代谢物变化。结果 脑胶质瘤的^1H—MRS表现：肌酸（Cr）轻度下降,N-乙酰天门冬氨酸（NAA）显著下降。胆碱（Cho）显著增高。低级别、高级别脑胶质瘤的肿瘤组织分别和对侧正常脑组织的NAA／Cr、Cho／Cr、NAA／Cho比值存在非常显著性差异（P〈0．01）;低级别脑胶质瘤和高级别脑胶质瘤的肿瘤组织的NAA／Cr、Cho／Cr、NAA／Cho比值存在显著性差异（P〈0．05）。脑胶质瘤的NAA／Cho、Cho／Cr、NAA／Cr比值与病理级别相关,其中NAA／Cho和Cho／cr比值反映肿瘤级别较稳定;NAA／Cr、NAA／Cho比值存在负相关关系（相关系数rs分别为-0．663,-0．851）,Cho／Cr比值存在正相关关系（相关系数rs为0．858）。结论 ^1H—MRS与MRI相结合能提高脑胶质瘤术前诊断的准确性。^1H-MRS可评价脑胶质瘤的分级,反映脑胶质瘤代谢特性以及肿瘤生长潜能。     

Quantitative proton MR spectroscopic imaging of normal human cerebellum and brain stem.

Quantitative, multislice proton MR spectroscopic imaging (MRSI) was used to investigate regional metabolite levels and ratios in the normal adult human posterior fossa. Six normal volunteers (36 +/- 3 years, five male, one female) were scanned on a 1.5 T scanner using multislice MRSI at long echo time (TE 280 msec). The entire cerebellum was covered using three oblique-axial slice locations, which also included the pons, mid-brain, insular cortex, and parieto-occipital lobe. Concentrations of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) were estimated using the phantom replacement technique. Regional variations of the concentrations were assessed using ANOVA (P < 0.05). High-resolution MRSI data was obtained in all subjects and brain regions examined. Metabolite concentrations (mM) (mean +/- SD) were as follows: cerebellar vermis: 2.3 +/- 0.4, 8.8 +/- 1.7 and 7.6 +/- 1.0 for Cho, Cr, and NAA respectively; cerebellar hemisphere: 2.2 +/- 0.6, 8.9 +/- 2.1, 7.5 +/- 0.8; pons 2.2 +/- 0.5, 4.3 +/- 1.1, 8.3 +/- 0.9; insular cortex, 1.8 +/- 0.5, 7.8 +/- 2, 8.0 +/- 1.1, parieto-occipital gray matter, 1.3 +/- 0.3, 5.7 +/- 1.1, 7.2 +/- 0.9, and occipital white matter, 1.4 +/- 0.3, 5.3 +/- 1.3, 7.5 +/- 0.8. Consistent with previous reports, significantly higher levels of Cr were found in the cerebellum compared to parieto-occipital gray and occipital white matter, and pons (P < 0.0001). NAA was essentially uniformly distributed within the regions chosen for analysis, with the highest level in the pons (P < 0.04). Cho was significantly higher in the cerebellum and pons than parieto-occipital gray and occipital white matter (P < 0.002) and was also higher in the pons than in the insular cortex (P < 0.05). Quantitative multislice MRSI of the posterior fossa is feasible and significant regional differences in metabolite concentrations were found.     

~1H-MRS在脑胶质瘤诊断及分级中的应用

目的:分析脑胶质瘤的氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)表现及其临床意义;探讨脑胶质瘤的1H-MRS特点与其病理级别相关性。方法:搜集经临床手术、病理证实的脑胶质瘤38例,按照WHO分级(2000)标准分成两组:低级别脑胶质瘤组、高级别脑胶质瘤组。所有患者在术前行1H-MRS检查,均在MR非增强成像的基础上获得。使用GE Signa1.5T超导磁共振扫描仪,多体素扫描,点分辨选择波谱法,检测不同区域代谢物变化。结果:脑胶质瘤的1H-MRS表现:肌酸(Cr)无明显变化;N-乙酰天门冬氨酸(NAA)下降,胆碱(Cho)增高,变化的程度由肿瘤级别高低决定;低级别、高级别脑胶质瘤的肿瘤组织分别和对侧正常脑组织的NAA/Cr、Cho/Cr、NAA/Cho比值存在显著性差异(P<0.01);低级别脑胶质瘤和高级别脑胶质瘤的肿瘤组织的NAA/Cr、Cho/Cr、NAA/Cho比值有统计学意义(P<0.05),脑胶质瘤的NAA/Cho、Cho/Cr、NAA/Cr比值与病理级别相关。结论:1H-MRS与MRI相结合能提高脑胶质瘤术前诊断的准确性。1H-MRS可评价脑胶质瘤的分级,反映脑胶质瘤代谢特性以及肿瘤生长潜能。     

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。     

质子磁共振波谱对脑肿瘤的鉴别诊断价值

目的初步探讨氢质子磁共振波谱(1H-MRS)对不同脑肿瘤的诊断及鉴别诊断价值.材料和方法39例颅内肿瘤分别行常规MRI及1H-MRS检查,将肿瘤实质与对侧相应部位及正常对照组行对照研究.检查方法为PRESS序列,主要观察代谢物为氮-乙酰天门冬氨酸(NAA)、含胆碱的化合物(Cho)、肌酸(Cr/PCr)、乳酸(Lac)和脂类(Lipids).结果几乎所有肿瘤波谱均呈现NAA峰降低,Cho升高,Cho/Cr及Cho/NAA比值升高,与正常组织相比有显著性差异(p＜0.05).低度恶性胶质瘤组8例Cho/Cr、NAA/Cr、NAA/Cho代谢物比值分别为1.87±0.45、1.13±0.26、0.74±0.21;高度恶性胶质瘤组7例的代谢物比值的均值分别为2.75±1.17、1.07±0.31和0.62±0.28;脑膜瘤组11例,其代谢物比值的均值分别为6.04±2.15、0和0;转移瘤组10例,其代谢物比值的均值分别为2.32±1.08、1.22±0.17和1.23±0.46.胶质瘤组2例术后与术前比较Cho/Cr比值有明显降低.淋巴瘤1例放疗后较放疗前Cho/Cr比值降低;听神经鞘瘤1例见升高的Cho峰;蛛网膜囊肿1例仅见Lac峰.结论H1-MRS对脑肿瘤的诊断及鉴别诊断、治疗后随访、手术后疗效的评价均有重要价值,可作为一种非损伤性的辅助诊断手段.     

Reproducibility of short echo time proton magnetic resonance spectroscopy using point-resolved spatially localized spectroscopy sequence in normal human brains.

The reproducibility of short echo time proton MR spectroscopy (1H-MRS) in normal human brains was examined. Thirteen healthy volunteers were studied, and each underwent three MRS examinations. Second and third measurements were done on the same day, about two months after the first measurement, and interday and intraday reproducibility were evaluated. MRS was performed with proton brain examination/single voxel (PROBE/SV) and point-resolved spatially localized spectroscopy (PRESS) (repetition time = 2000 ms, echo time = 30 ms). Five metabolite ratios were computed; N-acetyl-aspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (mI)/Cr, NAA/(NAA + Cr + Cho), and NAA/Cho. Their normal range and reproducibility were measured. For each metabolite ratio, there was no significant difference between interday difference and intraday difference, suggesting that the interval of two months has minimal effect on MRS measurements. MRS may be utilized for the observation of central nervous system diseases.     

A multicenter reproducibility study of single-voxel 1H-MRS of the medial temporal lobe

Proton magnetic resonance spectroscopy (¹H-MRS) has provided evidence for a reduction of N-acetyl-aspartate (NAA) in the medial temporal lobe (MTL) in cerebral disorders such as Alzheimer’s Disease. Within the ¹H-MRS study of the German Research Network on Dementia, we determined the multicenter reproducibility of single-voxel ¹H-MRS of the MTL. At five sites with 1.5T MR systems, single-voxel ¹H spectra from the MTL of an identical healthy subject were measured. The same subject was also examined at one of the sites five times to assess intracenter stability. The protocol included water-suppressed spectra with TE 272 ms and TE 30 ms and unsuppressed spectra for absolute quantification of metabolite concentrations. The intracenter reproducibility of absolute NAA concentration, expressed as coefficient of variation (CV), was 1.8%. CV for the concentrations of creatine (Cr), choline (Cho), and myoinositol (MI) and for the ratios NAA/Cr, NAA/Cho, and MI/NAA varied by 11–16%. Intercenter CV was 3.9% for NAA and were below 10% for all other metabolites and metabolic ratios. Our study demonstrates that quantitative assessment of NAA with single-voxel MRS can be performed with high intercenter reproducibility. This is the basis for applying ¹H-MRS in large-scale early recognition and treatment studies in MTL affecting disorders. The study is part of the German Research Network on Dementia and was funded by the German Federal Ministry for Education and Research (grant O1GI 0102)     

Proton spectroscopic metabolite signal relaxation times in preterm infants: a prerequisite for quantitative spectroscopy in infant brain

PURPOSE: To determine relaxation times of metabolite signals in proton magnetic resonance (MR) spectra of immature brain, which allow a correction of relaxation that is necessary for a quantitative evaluation of spectra acquired with long TE. Proton MR spectra acquired with long TE allow a better definition of metabolites as N-acetyl aspartate (NAA) and lactate especially in children. MATERIALS AND METHODS: Relaxation times were determined in the basal ganglia of 84 prematurely born infants at a postconceptional age of 37.8 +/- 2.2 (mean +/- SD) weeks. Metabolite resonances were investigated using the double-spin-echo volume selection method (PRESS) at 1.5 T. T1 was determined from intensity ratios of signals obtained with TRs of 1884 and 6000 msec, measured at 3 TEs (25 msec, 136 msec, 272 msec). T2 was determined from signal intensity ratios obtained with TEs of 136 msec and 272 msec, measured at 2 TR. Taking only long TEs reduced baseline distortions by macromolecules and lipids. For myo-inositol (MI), an apparent T2 for short TE was determined from the ratio of signals obtained with TE = 25 msec and 136 msec. Intensities were determined by fitting a Lorentzian to the resonance, and by integration. RESULTS: Relaxation times were as follows: trimethylamine-containing compounds (Cho): T1 = 1217 msec/T2 = 273 msec; total creatine (Cr) at 3.9 ppm: 1010 msec/111 msec; Cr at 3.0 ppm: 1388 msec/224 msec; NAA: 1171 msec/499 msec; Lac: 1820 msec/1022 msec; MI: 1336 msec/173 msec; apparent T2 at short TE: 68 msec. CONCLUSION: T1 and T2 in the basal ganglia of premature infants do not differ much from previously published data from basal ganglia of older children and adults. T2 of Cho was lower than previous values. T2 of Cr at 3.9 ppm and Lac have been measured under different conditions before, and present values differ from these data.     

Impact of cerebrospinal fluid contamination on brain metabolites evaluation with 1H‐MR spectroscopy: A single voxel study of the cerebellar vermis in patients with degenerative ataxias

Purpose

To investigate the impact of cerebrospinal fluid (CSF) contamination on metabolite evaluation in the superior cerebellar vermis with single‐voxel ¹H‐MRS in normal subjects and patients with degenerative ataxias.

Materials and Methods

Twenty‐nine healthy volunteers and 38 patients with degenerative ataxias and cerebellar atrophy were examined on a 1.5 Tesla scanner. Proton spectra of a volume of interest placed in the superior vermis were acquired using a four TE PRESS technique. We calculated N‐acetyl aspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and NAA/Cho ratios, T₂ relaxation times and concentrations of the same metabolites using the external phantom method. Finally, concentrations were corrected taking into account the proportion of nervous tissue and CSF, that was determined as Volume Fraction (VF).

Results

In healthy subjects, a significant difference was observed between metabolite concentrations with and without correction for VF. As compared to controls, patients with ataxias showed significantly reduced NAA/Cr and NAA concentrations, while only corrected Cr concentration was significantly increased. The latter showed an inverse correlation with VF.

Conclusion

CSF contamination has a not negligible effect on the estimation of brain metabolites. The increase of Cr concentration in patients with cerebellar atrophy presumably reflects the substitutive gliosis which takes place along with loss of neurons. J. Magn. Reson. Imaging 2009;30:11–17. © 2009 Wiley‐Liss, Inc.     

阿尔茨海默病的高场氢质子磁共振波谱研究

目的:探讨阿尔茨海默病(Alzheimer's disease,AD)双侧海马的高场氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)的特点.方法:对AD组14例及正常对照组(normal control,NC)10例受试者行T_1WI-3D薄层扫描并进行海马三平面MPR重建,在所得MPR图像上定位双侧海马.采用MRS测定双侧海马N-乙酰天门冬氨酸(N-acetyl aspartate,NAA)、胆碱(choline,Cho)、肌醇(myo-lnositol,mI)和谷氨酸-谷氨酰胺复合物(Glx)与肌酸(ereatine,Cr)的比值.采用SPSS 17.0软件进行统计分析,观察AD组与NC组双侧海马各代谢物比值的差异.结果:AD组双侧海马的NAA/Cr、Glx/Cr比值较NC组降低,其差异具有统计学意义,AD组右侧海马ml/Cr比值较NC组升高具有统计学意义(P<0.05),左侧海马mI/Cr比值有升高趋势.但未达到统计学意义水平,AD组双侧海马Cho/Cr比值与NC组的差异无统计学意义.结论:双侧海马的高场MRS能够检测到AD特征性的代谢物改变.T_1WI-3D扫描行海马三平面MPR重建有助于海马MRS的准确定位,提高图像质量及可信度.     

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。     

Human cervical lymphadenopathy: evaluation with in vivo 1H-MRS at 1.5 T

AIM: To evaluate the feasibility of performing in vivo proton magnetic resonance spectroscopy ((1)H-MRS) of cervical lymph nodes, and the clinical usefulness of the technique in the characterization of cervical lymphadenopathy. MATERIALS AND METHODS: Cervical lymphadenopathy was examined in 20 individuals with malignant disease, i.e. 10 with squamous cell carcinoma (SCC), 6 with undifferentiated carcinoma (UDC) and 4 with non-Hodgkin's lymphoma (NHL). Cervical lymphadenopathy was also examined in 4 individuals with benign disease, i.e. 3 with tuberculosis (TB) and 1 with Castleman's disease. A point-resolved spectroscopic sequence with echo times (TE) of 136 and 272 ms and a time-domain spectral fitting procedure were used to estimate peak amplitude of choline (Cho), creatine (Cr) and unsuppressed water. Cho/Cr and Cho/water ratios were measured for each lesion. The mean ratio for each lesion group was obtained and results were compared statistically. RESULTS: At TE of 136 ms, spectra were interpretable in all 24 cases and a Cr peak was identified with post-processing in 15 cases. The Cho/Cr and Cho/water ratios for NHL were 9.1 +/- 5.2 and 1.7 +/- 0.2 x 10(-3), for UDC were 4.4 +/- 0.9 and 1.2 +/- 0.4 x 10(-3), and for SCC were 2.1 +/- 0.6 and 0.5 +/- 0.3 x 10(-3), respectively. Both Cho/Cr and Cho/water ratios for UDC were significantly higher than SCC (p = 0.002 and 0.026, respectively). At TE of 272 ms, spectra were interpretable in 22 of 24 cases and a Cr peak was identified with post-processing in 11 cases. Cho/Cr and Cho/water ratios for NHL were 5.4 and 4.6 +/- 1.4 x 10(-3), for UDC were 4.2 +/- 1.5 and 2.6 +/- 1.0 x 10(-3) and for SCC were 2.5 +/- 1.1 and 1.3 +/- 0.6 x 10(-3), respectively. The Cho/water ratio for UDC was significantly higher than for SCC (p = 0.04). The Cho/Cr ratio for UDC was also higher than for SCC, but this difference was not statistically significant (p = 0.07). Neither Cho nor Cr was detected in the 3 cases of TB. CONCLUSION: In vivo (1)H-MRS is a feasible technique for the evaluation of cervical lymph nodes and it offers potential as a clinical tool in the investigation of cervical lymphadenopathy. However, further studies with larger patient cohorts are needed to validate the findings of this initial report.     

1.5 T在体兔正常肌肉及VX2软组织肿瘤1H-MRS成像技术研究

目的探讨1．5T磁共振仪行在体兔正常肌肉及VX2软组织肿瘤氢质子磁共振波谱（^1H-MRS）检查的可行性及成像技术。材料与方法20只新西兰大白兔。右大腿近段肌肉内注射VX2肿瘤组织悬液0．2ml,制成肿瘤模型。分别于接种前及接种后第40d行正常大腿肌肉及肿瘤MRI和^1H-MRS成像。波谱成像序列包括单体素和多体素点解析频谱（PRESS）序列,比较不同成像条件及参数下^1H-MRS曲线,在工作站上测量胆碱（Cho）／肌酸（Cr）及脂质峰（Lipid）／Cr比值并进行统计学分析。结果所有兔正常肌肉及VX2肿瘤^1H-MRS可见Cho峰、Cr峰及Lipid峰。与正常肌肉组织相比,VX2肿瘤组织Cho峰明显增高,Lipid峰降低。肿瘤组织与正常肌肉Cho／Cr及Lipid／Cr比值差异具有统计学意义。所有兔正常肌肉和VX2肿瘤的单体素PRESS序列成像质量优于多体素PRESS序列,冠状面定位优于横断面。单体素PRESS序列半高带宽（FWHM）小于8Hz,多体素FWHM小于12Hz,成像质量较好。根据采集兴趣区大小,词整视野或采集次数可提高波谱成像质量。实时测定兔体温并设定为波谱成像时的系统温度值可有效避免波峰漂移。结论在体^1H-MRS检查兔VX2软组织肿瘤与正常肌肉^1H-MRS表现明显不同^1H-MRS有望用于软组织肿瘤的诊断。优化成像条件与参数可明显提高波谱成像质量。     

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.     

颅内结核瘤的质子MR波谱研究

目的探讨质子MR波谱(1H-MRS)对颅内结核瘤的诊断价值。资料与方法回顾性分析26例颅内结核瘤患者术前或接受治疗前的1H-MRS表现,1H-MRS采用多体素2D1H-MRS,点分辨表面线圈法(PRESS)。比较结核瘤病灶实质和对侧正常脑组织的胆碱(Cho)、肌酸(Cr)、N-乙酰天门冬氨酸(NAA)、Cho/Cr,Cho/NAA、NAA/Cho差异有无统计学意义,观察有无脂质(Lip)峰或氨基酸峰(AAs)出现。结果颅内结核瘤实质部分Cho较对侧升高,差异无统计学意义(颅内结核瘤和对侧正常脑组织Cho分别为366.7±137.4,325.4±126.4,P>0.05),Cr、NAA、NAA/Cho低于对侧,差异有统计学意义(颅内结核瘤和对侧正常脑组织Cr分别为163.6±74.1,300.1±140.5,P<0.01;NAA分别为239.4±96.6,475.3±244.7,P<0.01;NAA/Cho分别为0.74±0.35,1.56±0.60,P<0.01),Cho/Cr、Cho/NAA高于对侧,差异有统计学意义(颅内结核瘤和对侧正常脑组织Cho/Cr分别为2.05±0.63,1.14±0.38,P<0...     

^1HMRS在脑梗塞中的临床应用

目的　应用氢质子磁共振波谱 (1HMRS)和化学位移成像 (chemicalshiftimaging ,CSI)研究人脑梗塞中代谢物随时间的变化规律 ,评价1HMRS在脑梗塞中的临床应用价值。材料与方法　 2 8例脑梗塞患者根据发作时间将其分为 :超急性期 (6小时内 ) 2例 ;急性期 (6小时后至 2天内 ) 6例 ;亚急性期 (2天后至 6周内 ) 12例 ;慢性期 (6周后 ) 8例。将正常对侧相同部位 2 0例作为自身对照组。应用定点分辨选择波谱 (pointedresolvedselectivespectroscopy ,PRESS) /TE 13 5msCSI和两侧相对应部位PRESS/TE 13 5ms单体素采集。测算N 乙酰天门冬氨酸 (NAA)、肌酸 (Cr)、含胆碱类化合物 (Cho)与对照组的比值及同侧NAA/Cho、NAA/Cr、Lac/Cho(乳酸 /含胆碱类化合物 )的变化。结果　超急性期 2例出现Lac而NAA、Cho、Cr改变不明显 ;急性期 5例Lac增加 ,NAA开始减少 ,Cr稍降低 ,Cho未见明显改变 ;亚急性期Lac进一步增加 ,2例复查患者 2周后Lac开始下降 ,但仍维持较高浓度 ,NAA继续减少 ,Cr降低 ,Cho稍减少 ;慢性期NAA、Cr进一步减少 ,3例在病灶区仍检测到一定浓度Lac ,5例未见明显的Lac ,3例 6个月后病灶边缘Cho浓度比对侧高 ,5例Cho降低。另外 3例亚急性期、2例慢性期明显脂肪峰。同对照组比较 ,2 8例患者总的NAA下降最明显 ,     

多体素~1H-MRS对星形细胞肿瘤边界诊断的研究

目的：探讨多体素^1H-MRS在星形细胞瘤边界诊断中的临床应用价值。方法：对20例经病理证实的星形胶质细胞瘤患者行多体素^1H-MRS检查,采集NAA、Cho、Cr等波峰,计算并比较肿瘤不同区域多种代谢物比值。结果：多体素^1H-MRS示肿瘤区、近侧瘤周区NAA/Cho、NAA/Cr和Cho/Cr平均值与参照区比较差异均有显著性意义（P〈0.05）;高、低级星形细胞瘤间,多组代谢物比值差异具有统计学意义（P〈0.05）。结论：MRS示Ⅲ～Ⅳ级星形细胞瘤在肿瘤区边缘2cm范围代谢物比值仍和参照区差异有显著统计学意义,提示存在肿瘤浸润,Ⅰ～Ⅱ级星形细胞瘤在肿瘤区边缘1cm范围代谢物比值仍和参照区差异有显著统计学意义,提示存在肿瘤浸润。     

3T 1H-MR spectroscopy in grading of cerebral gliomas: comparison of short and intermediate echo time sequences

BACKGROUND AND PURPOSE: Echo time (TE) can have a large influence on the spectra in proton MR spectroscopy ((1)H-MR spectroscopy). The purpose of this study was to comparatively assess the diagnostic value of 3T single-voxel (1)H-MR spectroscopy with short or intermediate TEs in grading cerebral gliomas. METHODS: Single voxel (1)H-MR spectroscopy was performed at 3T in 35 patients with cerebral glioma. The spectra were obtained with both short (35 ms) and intermediate TEs (144 ms). Metabolite ratios of choline (Cho)/creatine (Cr), Cho/N-acetylaspartate (NAA), lipid and lactate (LL)/Cr and myo-inositol (mIns)/Cr were calculated and compared between short and intermediate TEs in each grade. After receiver operating characteristic curve analysis, diagnostic accuracy for each TE in differentiating high-grade glioma from low-grade glioma was compared. RESULTS: At short TE, Cho/Cr and Cho/NAA ratios were significantly lower, and LL/Cr and mIns/Cr were significantly higher, compared with those at intermediate TE, regardless of tumor grade. Lactate inversion at intermediate TE was found in only 2 patients. At both TEs, there were significant differences in Cho/Cr and LL/Cr ratios between low- and high-grade gliomas. Diagnostic accuracy was slightly higher at short TE alone or combined with intermediate TE than intermediate TE alone (85.7% versus 82.9%). CONCLUSION: Metabolite ratios were significantly different between short and intermediate TE. Cho/Cr and LL/Cr ratios at either TE were similarly useful in differentiating high-grade gliomas from low-grade gliomas. If only a single spectroscopic sequence can be acquired, short TE seems preferable because of poor lactate inversion at intermediate TE on 3T single-voxel (1)H-MR spectroscopy.     

Infantile tuberous sclerosis changes in the brain: proton MR spectroscopy findings.

A parietal hamartoma of a three-month-old boy with tuberous sclerosis was studied with magnetic resonance (MR) imaging, and proton MR spectroscopy. MR spectra were obtained with the single-voxel PRESS (point resolved spectroscopy; TR = 1500 ms, TE = 135 ms) sequence, in a 8 cc region of interest. Apparently low NAA/Cho (0.28), and NAA/Cr (0.37) ratios were noted in the hamartoma, that could suggest a neoplasm. The lesion and the surrounding brain tissue were studied again after seven months with spectroscopic imaging using the chemical shift sequence (TR = 1500 ms. TE = 40 ms). This study revealed apparently improved NAA/Cho (2.63), NAA/Cr (2.13) ratios in the hamartoma compared to the initial examination at three months of age, excluding the possibility of a neoplasm.     

Usefulness of Cho/Cr ratio in proton MR spectroscopy for differentiating residual/recurrent glioma from non-neoplastic lesions

PURPOSE: We evaluated the clinical usefulness of the Cho/Cr ratio of proton MR spectroscopy(1H-MRS) to differentiate residual/recurrent glioma from non-neoplastic lesions. PATIENTS AND METHODS: 20 cases of glioma were involved in this study(astrocytoma grade I-II: 7, oligodendroglioma: 1, astrocytoma grade III: 2, glioblastoma: 10). Seven of the patients underwent surgical resection only, 4 underwent surgical resection and radiotherapy(40-60 Gy), and 9 underwent surgical resection and radiotherapy with concurrent chemotherapy(14-60 Gy). 1H-MRS was performed on a 1.5 Tesla clinical MR unit using a 3D-chemical shift imaging sequence(1500 msec/270 msec/1 (TR/TE/excitations), and the Cho/Cr ratio was calculated in the voxel where neoplastic lesion was most suspected on MRI. The presence of lactate + lipid peak was also evaluated. All spectra were obtained after the contrast enhanced study. RESULTS: Cho/Cr ratios were significantly higher in cases of residual/recurrent tumors(mean +/- SD = 1.70 +/- 0.96) than in non-neoplastic lesions(mean +/- SD = 1.04 +/- 1.16) (Mann-Whitney U-test p = 0.047). If a Cho/Cr ratio of more than 1.5 was used as a marker of tumor presence, its sensitivity was 64%, specificity 83%, and accuracy 70%. One false-positive case that of radiation necrosis whose spectrum showed a high Cho/Cr ratio with markedly elevated lactate + lipid peak. CONCLUSION: The Cho/Cr ratio of 1H-MRS provides additional information to MRI in differentiating residual/recurrent gliomas from non-neoplastic lesions.