MR弥散、灌注成像及1H-MRS在判断脑肿瘤放疗后坏死与肿瘤复发诊断中的应用

目的 :试探讨弥散、灌注成像及1H MRS在放射性坏死与脑肿瘤复发鉴别诊断中的作用。材料和方法 :对象 :肿瘤复发和放射性坏死的脑肿瘤患者 2 8例 ,男 17例 ,女 11例。年龄 12～ 6 6岁。检查方法 :MR弥散、灌注成像和1H MRS检查。结果 :脑肿瘤复发 16例 ,放射性坏死 12例。影像表现 :脑肿瘤复发 :弥散成像信号多样 ;灌注成像 :局部高信号 ;1H MRS :Cho上升 ,NAA下降 ,以Lip Lac波升高。放射性坏死 :弥散成像信号多样 ;灌注成像低信号 ;1H MRS :Cho、NAA、Cr均较低。结论 :MRI弥散、灌注成像及1H MRS对判断脑肿瘤放疗后坏死还是肿瘤复发有意义。     

^1H磁共振波谱在胶质瘤放疗后复发和放射性脑坏死鉴别中的初步应用

目的：探讨质子磁共振波谱（^H MRS）对胶质瘤放射后复发和放射性脑坏死鉴别诊断的价值。方法：15例有脑部放疗史,临床及CT、MRI难以判断为肿瘤复发或放射性脑坏死的患者5例病史明确的放射性脑坏死的患者,均行^H MRS检查,结果：15例经手术证实,14例为胶质瘤1例放射性脑坏死,^H MRS诊断正确。（1）14例胶质瘤在^H MRS上均表现为明显增高的胆碱（Cho)峰,氮乙酰门冬氨酸（NAA）,肌酸（Cr)峰下降 或消失,Cho/Cr比值升高,NAA／Cr比值降低;12例出现乳酸（Lac)峰。（2）放射性脑坏死表现为：5例Cho,NAA,Cr下降或消失,出现脂质（Lipid)峰;1例Cho,NAA,Cr峰均消失,仅表现一较平坦的曲线,无Lac峰。结论^H MRS对胶质瘤疗后复发和放射性脑坏死的鉴别有重要价值。     

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。     

磁共振氢质子波谱序列PRESS和STEAM比较

目的：比较短TEPRESS与STEAM两种氢质子波语序列在脑肿瘤诊断中的优劣。方法：43例脑肿瘤的^1H—MRS，除了TE稍不同外，PRESS和STEAM序列的其他参数全部相同。结果：PRESS与STEAM在检测肿瘤Cr的浓度方面，其差异有显著性意义，其因素可能和序列的特征有关，而对NAA、Cho、mi、NAA／Cr、Cho／Cr具有良好的一致性，且PRESS波语的信噪比好，检查时间短。结论：PRESS可取代STEAM作为脑肿瘤的波语检查序列之一。     

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。     

多体素氢质子MR波谱结合ADC鉴别胶质瘤复发与放射性坏死

目的探讨多体素氢质子MR波谱(1H-MRS)联合ADC图鉴别胶质瘤术后放疗后复发与放射性坏死的临床应用价值。方法回顾分析我院38例胶质瘤术后放疗后行MR检查发现异常强化病灶患者的1H-MRS和ADC图资料。测量强化区、水肿区以及正常脑组织区的胆碱(Cho)/肌酸(Cr)、Cho/N-乙酰天冬氨酸(NAA)、NAA/Cr及ADC值。比较复发与放射性坏死两组间Cho/Cr、Cho/NAA、NAA/Cr以及病灶-对侧相对ADC(r ADC)值的差异。ROC曲线分析各参数值最佳诊断界值及对应的诊断敏感性、特异性。结果胶质瘤术后复发17例,放射性坏死21例。复发组强化区、水肿区的Cho/Cr、Cho/NAA均明显高于放射性坏死组(P0.05)。复发组强化区r ADC值低于放射性坏死组(P0.05)。强化区Cho/Cr、Cho/NAA、r ADC值最佳诊断界值分别为2.470、2.825、0.538。水肿区Cho/Cr、Cho/NAA最佳诊断界值分别为1.345、1.750。结论临床可联合应用多体素1H-MRS和ADC图对胶质瘤术后放疗后复发与放射性坏死进行鉴别诊断,从而有助于及时合理的选择个体化治疗方案。     

MRS在星形细胞肿瘤术后放疗中的价值:Cho/Cr的变化及意义

目的:研究星形细胞肿瘤术后、分次放疗后急性期及早期迟发反应期MRS上Cho/Cr随剂量、时间的变化趋势。方法:共18例,年龄9~67岁(平均46±14岁),采用GE signa VH/i 3.0T成像系统进行检查,MRS采用多体素PRESS序列。均为术后患者(全切或部分切除),其中胶质母细胞瘤(WHO 4级)7例,间变性星形细胞瘤(WHO 3级)4例,弥漫性星形细胞瘤(WHO 2级)6例,毛细胞型星形细胞瘤(WHO 1级)1例。测量两个体素:≥60Gy区(肿瘤床区)和<40Gy区(对侧正常区)。一般先行常规分割放射治疗,然后进行调强适形放射治疗,靶区总处方剂量为60~68Gy。结果:≥60Gy区的Cho/Cr在放疗至60%总剂量时已经开始降低,并且呈进行性降低(从治疗前的2.521降到治疗后1个月的1.810)。而<40Gy区则先轻度升高,随后降至原来的水平。结论:MRS的Cho/Cr可以对星形细胞肿瘤术后、放疗后急性期和早期迟发反应期的代谢物改变进行检测,有利于对肿瘤治疗后的早期反应进行有效评估。     

单体素1H-MRS分析在评估脑胶质瘤放疗效果中的应用研究

目的 探讨单体素氢质子磁共振波谱(1H-MRS)分析在评估脑商胶质瘤放疗效果中的应用价值.资料与方法 对28例Ⅱ～Ⅳ级脑胶质瘤术后患者于放疗前及放疗后1-2个月行MRI增强检查及1H-MRS检杳,测定各丰要代谢产物峰下面积,并计算出病灶波谱参数胆碱(Cho)/肌酸(Cr)、Cho/N-乙酰天门冬氨酸(NAA)、NAA/Cr比值及脂质(Lip)波、乳酸(Lac)波出现概率.以放疗后5～10个月MRI增强扫描结果及二次手术结果为随访标准进行分组,即放疗后抑制组、放疗后复发组及放射性脑损伤组,对各组放疗前后的波谱参数进行对照,验证1H-MRS参数与放疗效果的相关性.结果 肿瘤抑制组表现为Cho浓度及Cha/Cr、Cho/NAA比值显著降低(P<0.05),NAA、Cr浓度有所下降,Lip-Lac波出现增多.肿瘤复发组Cho浓度及Cho/Cr、Cho/NAA比值仍显著升高,Cr浓度中度升高,出现更多的Lip-Lac波,仍表现为特征性肿瘤波谱.放射件脑损伤组Chw/Cr、Cho/NAA比值较放疗前轻度上升,远不及复发组上升明显,NAA及Cr浓度下降.结论 单体素1H-MRS能从代谢方面无创伤地监测脑胶质瘤放疗后的组织代谢、生理生化改变,具有早期评价胶质瘤放疗疗效的优越性.     

1HMRS在脑肿瘤中的应用

^1H MRS能无创性的提供脑肿瘤的生化信息，是传统影像学方法所不能获得的。本文主要综述了^1H MRS在不同脑肿瘤中代谢物的变化及其对脑肿瘤诊断、鉴别诊断、肿瘤转归、穿刺活检定位等方面的应用。     

3．0T磁共振多体素^1H-MRS和DWI对常见脑肿瘤特征分析的价值

目的：探讨3．0T磁共振多体素^1H-MRS及DWI在常见颅内肿瘤特征分析的价值。方法：脑肿瘤患者30例,多体素^1H-MRS感兴趣区包括肿瘤实质区、瘤周水肿区及正常参照区。计算上述各区域的NAA、Cho、Cr等多种代谢物的值;DWI测量肿瘤不同部位信号值,计算ADC值。结果：胶质瘤、转移瘤、脑膜瘤三者之间肿瘤实质区的NAA／Cho、NAA／Cr和Cho／Cr平均值与参照区比较有显著性差异（P〈0．05）;高、低级别胶质瘤间瘤周水肿区的NAA／Cho和Cho／Cr具有统计学差异（P〈0．05）,高级别胶质瘤与转移瘤间瘤周水肿区的NAA／Cho、NAA／Cr和Cho／Cr均有统计学差异（P〈0．05）。DWI示高、低级别胶质瘤间肿瘤实质区及瘤周水肿区的ADC值均有显著性差异（P〈0．05）;高级别胶质瘤与转移瘤间瘤周水肿区的ADC值有统计学差异（P〈0．05）。结论：多体素^1H-MRS与DWI相结合有助于脑肿瘤的特征分析、胶质瘤恶性程度分级、确定病灶浸润范围等。     

Short-echo time proton MR spectroscopy in the presence of gadolinium

PURPOSE: The purpose of this work was to quantify the impact of contrast agents on short-TE single-voxel 1H MR spectroscopy (MRS) diagnosis of recurrent brain tumors. METHOD: Short-TE 1H MRS was performed in 49 patients with biopsy-proven brain tumors and 14 control subjects. Eight patients (nine paired exams) were examined before and after administration of Gd-DTPA (interval approximately 5-7 min). RESULTS: Tumor spectra showed increased choline/creatine ratio (Cho/Cr; p < 0.009) and Cho concentrations (p < 0.02). Receiver operator characteristic for Cho/Cr = 0.93 differentiated 100% of tumors from control in the absence or presence of contrast agent. Repeated 1H MRS varied <3%. Cho T2 was significantly longer than Cr T2 (p < 0.02). CONCLUSION: Proton MRS with TE of 30 ms may safely be used in combined contrast-enhanced MRI/MRS protocols. Further study is required with long-TE MRS because of the prolonged T2 of Cho.     

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。     

MRS在脑内占位病变诊断中的应用

目的评价MRS对颅内占位性病变的临床应用价值。方法采用3DPRESS序列,结合MRI对52例经手术/立体定向活检或临床随诊证实的脑内占位及肿瘤术后复发患者进行扫描。结果52例患者中,肿瘤38例,诊断正确率为89.5%(34/38),14例非肿瘤病变,诊断正确率为78.6%(11/14)。胶质瘤的MRSI表现为Cho升高,NAA消失或明显降低,肿瘤实质及中央坏死区Lac升高,周围脑组织有相似改变;转移瘤MRS表现为Cho明显升高,NAA及Cr消失或明显降低,Lac升高,而瘤旁脑组织MRS波形正常或有轻度改变;淋巴瘤显示Cho升高,NAA中度降低,Lac升高,Lip峰的出现为其特征,瘤周MRS正常;脱髓鞘病变NAA轻至中度降低,Lac出现,而Cr无明显变化。放疗后反应MRS各代谢峰明显降低或消失,Cho下降幅度较NAA及Cr为小,随时间延长下降幅度明显增加,至放射性坏死时,各波峰均消失。脑脓肿MRS表现为Lac升高,在2.0ppm出现复合峰,NAA峰消失,Cho及Cr降低,而脓肿旁脑组织MRS正常。结论MRS作为无创性的诊断手段,对脑内病变的鉴别诊断及病变范围的确定有重要作用。     

Serial proton MR spectroscopic imaging of recurrent malignant gliomas after gamma knife radiosurgery

BACKGROUND AND PURPOSE: The diagnosis of brain tumors after high-dose radiation therapy is frequently limited by the lack of metabolic discrimination available with conventional imaging methods. The purpose of this study was to use proton MR spectroscopy to investigate serial changes in recurrent malignant gliomas after gamma knife radiosurgery to characterize tissue response to high-dose radiation. METHODS: Eighteen patients with recurrent gliomas were studied with MR imaging and 3D proton MR spectroscopic imaging at the time of radiosurgery and at regular time points thereafter. Choline (Cho) and N-acetyl aspartate levels were calculated on a voxel-by-voxel basis and compared with levels found in normal tissue and with levels observed at previous time points. The results of the spectral analysis were then compared with the radiologic findings. Statistical comparisons were precluded by the small sample sizes involved. RESULTS: Response within the gamma knife target was observed as a reduction of Cho levels and an increase in lactate/lipid levels, typically within 6 months of treatment. Increases in Cho correlated with poor radiologic response and suggested tumor recurrence, confirmed histologically in six cases. The development of a spectral abnormality preceded a coincident increase in contrast enhancement by 1 to 2 months in nine cases. CONCLUSION: Proton MR spectroscopic imaging provided diagnostic and monitoring information before and after radiosurgery. Evaluation of metabolic changes with proton MR spectroscopy and structural changes with MR imaging improved tissue discrimination and provided correlation with histologic findings.     

3D多体素1H-MRS对星形细胞瘤分级的诊断价值

目的探讨3D多体素质子波谱成像(1H-MRS)对脑低、高级星形细胞瘤鉴别诊断的价值和限度。资料与方法前瞻分析60例星形细胞瘤患者的传统平扫加增强及3D多体素1H-MRS资料,病理分为高级别组(WHOⅢ、Ⅳ级)和低级别组(WHOⅠ、Ⅱ级)。结果(1)传统MR平扫加增强诊断高级别星形细胞瘤的敏感性为70.5%、特异性为68.8%。(2)瘤体实质区胆碱(Cho)/N-乙酰天门冬氨酸(NAA)的敏感性82.0%,特异性81.0%;瘤周区Cho/NAA的敏感性77.0%,特异性81.0%;瘤体实质区乳酸(Lac)/肌酸(Cr)的敏感性82.0%,特异性88.0%;瘤周区乳酸盐(Lac)/肌酸(Cr)的敏感性91.0%,特异性69.1%。结论同传统MR相比,1H-MRS 3D多体素检查能增加星形细胞瘤分级诊断的敏感性,是传统MR检查的一种重要补充。     

Proton MR spectroscopy of delayed cerebral radiation in monkeys and humans after brachytherapy.

PURPOSETo determine whether radiation necrosis can be differentiated from residual/recurrent tumor by proton MR spectroscopy.METHODSWe studied the effects of interstitial brachytherapy on the brains of healthy monkeys and in humans with glioblastoma multiforme. The effects of radiation therapy on normal brain tissue in monkeys were assessed with sequential proton MR spectroscopic studies 1 week to 6 months after brachytherapy. Proton MR spectroscopy was also performed in five patients with residual/recurrent glioblastoma multiforme (three of whom had radiation necrosis after brachytherapy), seven patients with newly diagnosed untreated glioblastoma multiforme, and 16 healthy volunteers, who served as a control group.RESULTSIn monkeys, the ratio of N-acetylaspartate (NAA) to creatine-phosphocreatine (Cr) and the ratio of choline-containing compounds (Cho) to Cr of the reference point were significantly lower 1 week after brachytherapy than before treatment. The ratio of NAA to Cho of the irradiated area tended to be higher 1 week after brachytherapy than before irradiation. These peak metabolic ratios showed characteristic changes 6 months after treatment. In two of three monkeys, lipid signal was elevated 6 months after irradiation. In the clinical study, the ratio of NAA to Cho in the area of radiation necrosis was significantly different from that in glioblastoma multiforme when compared with the contralateral hemisphere after irradiation. In addition, lipid signal was detected in all patients with radiation necrosis.CONCLUSIONIt might be possible to use proton MR spectroscopy to differentiate radiation necrosis from residual/recurrent glioblastoma multiforme on the basis of comparisons with the contralateral hemisphere after radiation therapy.     

MR波谱在鼻咽癌放疗后颅底复发与放射性脑病鉴别诊断中的应用

目的 应用MR波谱(MRS)对鼻咽癌颅底复发与放射性脑病进行对比研究,探讨MRS对两者的鉴别诊断价值.方法 选择鼻咽癌根治性放射治疗后经常规MRI怀疑鼻咽癌颅底复发或放射性脑病患者50例行MRS,其中男44例,女6例,经临床及MRI复查综合诊断,26例为鼻咽癌颅底复发,24例为颞叶放射性脑病.对比分析放疗后复发与放射性脑病之间及其与相对"正常"脑组织之间胆碱(Cho)、N-乙酰天冬氨酸(NAA)、肌酸(Cr)、乳酸-脂质(LL)等主要代谢物含量的异同.采用秩和检验对所得数据进行统计分析.结果 复发组的Cho/Cr、Cho/NAA、LL/Cr中位数分别为2.22、2.13、1.77,放射性脑病组分别为1.40、1.31、0.57,两者间差异有统计学意义(P值均<0.01),复发组高于放射性脑病组.肿瘤复发组Cho、Cr、NAA的中位数分别为3366.00、1023.00、1930.00,放射性脑病组分别为2469.50、1864.50、1734.00,3个代谢产物的含量在肿瘤复发与放射性脑病之间差异均无统计学意义(P值均>0.05).在取得了"正常"脑组织对比的14个肿瘤复发病例中,复发灶的Cr、NAA、LL、Cho/Cr、Cho/NAA、LL/Cr的中位数分别为1023.00、1930.00、2090.00、3.76、2.13、3.39,"正常"区域分别为2370.00、3012.00、1680.00、1.64、1.17、0.75,两组各参数间差异均有统计学意义(P值均<0.05),复发灶的LL、Cho/Cr、Cho/NAA、LL/Cr高于"正常"区域,而NAA、Cr低于"正常"区域;在取得了"正常"脑组织对照的12个放射性脑病病例中,放射性脑病的Cho、Cr、NAA、LL、Cho/Cr、LL/Cr的中位数分别为390.00、217.50、427.50、39.00、1.30、0.40,而"正常"脑组织分别为680.00、360.00、610.00、30.00、1.54、0.09,上述参数在放射性脑病与其"正常"区域之间差异有统计学意义,放射性脑病的Cho(P<0.01)、Cr(P<0.01)、NAA(P<0.01)、Cho/Cr(P<0.05)低于"正常"区域,而放射性脑病的LL(P<0.05)、LL/Cr(P<0.01)高于"正常"组织.结论 鼻咽癌放疗后复发与放射件脑病在MRS上主要代谢物的变化各有特点,尤其是Cho/Cr、Cho/NAA、LL/Cr等指标复发灶明显高于放射性脑病,对于两者的鉴别诊断具有很高的价值.     

1.5 T磁共振兔VX2肝癌活体二维多体素1H-MRS应用初探

目的探讨应用1.5 T磁共振仪对兔VX2肝癌进行活体二维多体素氢质子磁共振波谱（1H-MRS）检查的可行性,对所得1H-MRS图作初步观察. 材料与方法采用经腹腔瘤块种植法建立兔VX2肝癌模型,利用1.5 T磁共振仪进行常规MR平扫和二维多体素1H-MRS,包括激励回波采样模式（STEAM）和点分辨波谱（PRESS）序列检查,初步比较肿瘤实质、瘤周和邻近正常肝组织的1H-MRS图的差别.扫描结束次日处死动物,取其相应位置肝脏组织块进行病理组织学分析. 结果建立兔VX2肝癌模型共计16只,均按照计划进行了MR平扫和二维多体素1H-MRS检查,共24瘤次,其中22瘤次获得令人满意的1H-MRS图,技术成功率达到92.0%.1H-MRS图上可见4个主要的波峰,包括脂质（Lip）、谷氨酰胺和谷氨酸复合物（Glx）、胆碱（Cho）、糖原和葡萄糖复合物（Glyu）.发现瘤周和邻近正常肝组织内Cho峰和Glyu峰较肿瘤实质内的要高,Lip峰稍降低.其他参数相同的情况下,STEAM和PRESS序列在本研究1H-MRS扫描中所得波谱谱图无明显区别. 结论应用1.5 T磁共振仪对兔VX2肝癌进行活体二维多体素1H-MRS检查是可行的.     

Multivoxel proton MR spectroscopy and hemodynamic MR imaging of childhood brain tumors: preliminary observations.

PURPOSETo assess multivoxel proton MR spectroscopy combined with MR imaging and hemodynamic MR imaging in the evaluation of brain tumors in children and young adults.METHODSFifteen patients with brain tumors and 10 healthy children underwent MR imaging and MR spectroscopy on a 1.5-T system. Ten patients with tumors had both MR spectroscopy and hemodynamic MR imaging. MR spectroscopy data sets with 1 cm3 to 3.4 cm3 resolution were acquired within 8.5 minutes by using a point-resolved spectroscopic, chemical-shift imaging technique in two dimensions with volume preselection. MR imaging was performed using fast spin-echo techniques. Hemodynamic MR imaging data were acquired every 2.5 seconds at one anatomic level using a spoiled gradient-echo sequence during intravenous bolus administration of contrast material.RESULTSAssessment with multivoxel MR spectroscopy and hemodynamic MR imaging added about 30 minutes to the total MR examination time. Normal tissue exhibited spectral peaks from biologically significant compounds such as N-acetylaspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Twelve biopsy-proved tumors exhibited prominent Cho, reduced NAA, variable tCr, and/or lactate or lipids, and two showed increased hemodynamic parameters. Three of the tumors treated with radiation did not reveal prominent levels of Cho. Tissue necrosis had no Cho, NAA, or tCr, and reduced hemodynamics.CONCLUSIONSPreliminary findings by MR spectroscopy combined with MR imaging and hemodynamic MR imaging suggest that regions of active tumor may be differentiated from areas of normal tissue and areas of necrosis. These findings may enable metabolic and hemodynamic characterization of childhood brain tumors as well as suggest their response to therapy.     

鼠脑C6胶质瘤模型在体MRS改变与病理

目的:研究MRS各代谢物相对定量值在大鼠C6胶质瘤模型不同部位的改变及病理表现.方法:32只C6胶质瘤模型,采用GE Signa VH/i3.0T成像系统、大鼠专用线圈进行检查,MRS采用多体素PRESS序列,Functool软件包后处理.在波谱后处理时需要选择3个体素:肿瘤区域、瘤周区域和对侧正常区.检查结束后处死大鼠,行病理学检查.结果:C6胶质瘤模型不同区域的MRS改变显示:①Cho/Cr、Cho/NAA、LL/Cr在肿瘤区域、瘤周区域、对侧正常区域间存在显著统计学差异;②NAA/Cr在肿瘤区域与瘤周区域、对侧正常区域间有统计学差异;③Lip0.9/Cr在肿瘤区域与瘤周区域、对侧正常区域有显著统计学差异;④Glx/Cr在肿瘤区域与对侧正常区域有显著统计学差异.结论:MRS为我们提供了无创性对星形细胞肿瘤进行评价的方法,在星形细胞肿瘤的诊断、瘤周区域的区分等方面起着一定的作用.