放射性脑损伤^1H-MRS研究进展

放射性脑损伤是颅内肿瘤放射治疗后的常见并发症,近年来^1H-MRS在放射性脑损伤的早期诊断及与肿瘤复发鉴别方面的研究发展迅速。就放射性脑损伤的发病机制、^1H-MRS研究进展及存在的问题予以综述。     

放射性脑损伤的MRI诊断

放射性脑损伤是头颈部痰病放射治疗后常见的并发症，按其出现的时间分为三期：急性期、早期迟发性反应期和晚期迟发性反应期。就放射性脑损伤的发病机制，临床病理及在MRI、磁共振血管成像(MRA)、磁共振波谱(MRS)、灌注成像的表现加以综述。     

子宫肿瘤~1H-MRS研究

目的:探讨子宫肿瘤活体1 H-MRS表现特点。方法:53例经病理证实的子宫肿瘤患者,其中良性9例,均为子宫肌瘤;恶性44例,包括子宫内膜癌13例、子宫颈癌27例和肉瘤4例。全部病例均于手术或活检前行1 H-MRS检查。波谱序列采用3.0T MR扫描、8通道体部线圈、单体素、点分辨表面波谱(PRESS)技术。定量分析肿瘤内的胆碱(3.2ppm)、不饱和脂肪酸(2.0ppm)、甘油三酯-CH2(1.3ppm)及-CH3(0.9ppm)含量。结果:4种化合物的峰值在所有恶性肿瘤中均分别高于良性肿瘤,但仅甘油三酯-CH3峰值在良恶性肿瘤组中差异有统计学意义(P=0.023)。不同病理类型中,子宫内膜癌的胆碱峰值最高(6.92×106),与子宫颈癌(3.25×106)及子宫肌瘤(3.15×106)差异均有高度统计学意义(P<0.001及P=0.008)。甘油三酯-CH3峰值在子宫肌瘤与子宫内膜癌、子宫肌瘤与子宫颈癌间差异均有统计学意义(P=0.037和0.042)。子宫颈癌的甘油三酯-CH2及-CH3峰值均高于其它类型肿瘤,但甘油三酯-CH2峰值在各病理类型中差异无统计学意义。结论:3.0T活体1 H-MRS能够从分子水平反映肿瘤代谢状态,对子宫良恶性肿瘤的鉴别有一定意义。     

放射性脑损伤和脑肿瘤复发的鉴别诊断

放射性脑损伤是放射治疗的严重的并发症,其与脑肿瘤复发的鉴别诊断非常困难,目前主要依靠影像学诊断,核磁共振弥散加权像、磁共振波谱、正电子发射型计算机体层显像、单光子发射计算机体层显像等被认为对于鉴别诊断有一定的帮助,但其敏感性和特异性还有待于进一步研究。最终确诊依赖标本的组织学检查。     

大鼠放射性脑损伤的MRS、PWI研究

目的研究大鼠放射性脑损伤不同时期的MRS、PWI表现,为其早期诊断提供依据。方法将成年大鼠30只随机分为对照组和照射组,照射前均行MRI、MRS及PWI检查。照射组分别于照射后1、3、6、9及12个月行MRI、MRS及PWI检查,计算NAA/Cr和Cho/Cr比值,测量灌注后大鼠双侧侧脑室周围的rCBV值。结果 1各照射组大鼠的NAA/Cr比值与对照组相比逐渐下降,差异均有统计学意义(P0.05);照射后Cho/Cr比值先上升,3个月时达峰值,随后逐渐下降,6个月内各组的Cho/Cr与对照组相比有统计学意义(P0.05);2照射1个月后各组的rCBV值均明显低于对照组,差异有统计学意义(P0.05)。结论 MRS及PWI能在放射性脑损伤发生形态学改变之前检测出脑组织代谢及灌注异常,为放射性脑损伤的早期诊断提供依据。     

放射性脑损伤的磁共振波谱研究进展

磁共振波谱成像(magnetic resonance spectroscopy,MRS)是基于核磁共振的原理发展起来的,因其可对脑组织内各种代谢物的化学浓度进行体外测量,现已成为一种重要的无创性检测活体组织的生化特性及代谢变化的诊断工具。目前,国内外MRS的功能研究已成为热点[1],但在放射性脑损伤研     

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.     

软组织肿瘤良恶性鉴别的术后标本~1H-MRS研究

目的：探讨术后标本1H-MRS鉴别软组织肿瘤良恶性的意义。方法：29例软组织肿瘤术后新鲜标本行常规MRI及1H-MRS测量,比较良、恶性肢体软组织肿瘤在1H-MRS代谢物胆碱（Cho）、肌酸（Cr）、三甲胺（TMA）、N-乙酰天门冬胺酸（NAA）、细胞内脂质IMCL（Lip1）、细胞外脂质EMCL（Lip2）相对浓度（即代谢物峰下平均面积）及Cho/Cr、TMA/Cr、NAA/Cr、Lip1/Cr、Lip2/Cr相对浓度比值,进行差异的t检验。结果：良性软组织肿瘤共11例,各代谢物相对浓度比值之均值分别为TMA/Cr1.02±0.50,Cho/Cr0.98±0.60,NAA/Cr0.46±0.34,Lip1/Cr7.88±6.23,Lip2/Cr5.72±4.46。恶性软组织肿瘤共18例,各代谢物相对浓度比值之均值分别为TMA/Cr2.47±1.04,Cho/Cr2.02±0.72,NAA/Cr0.41±0.39,Lip1/Cr1.41±1.31、Lip2/Cr1.01±0.93。本组资料用于诊断的恶性软组织肿瘤的TMA/Cr、Cho/Cr的阈值分别为1.19和1.21,其准确度分别为96.3%和88.9%,其诊断准确性均位于较高水平。用于诊断的良性软组织肿瘤的Lip1/Cr、Lip2/Cr的阈值分别为2.03和0.82,其准确度分别为90%及80%,其诊断准确性分别位于较高及中等水平。用于诊断的良性软组织肿瘤的NAA/Cr的阈值为0.035,其准确度分别为57%,其诊断价值位于较低水平。结论：Cho/Cr、TMA/Cr、Lip1/Cr、Lip2/Cr比值可作为软组织肿瘤良、恶性程度鉴别诊断的依据。     

鼻咽癌放疗后放射性脑损伤分析

鼻咽癌 (ｎａｓｏｐｈａｒｙｎｇｅａｌｃａｒｃｉｎｏｍａ ,ＮＰＣ)是我国最常见的恶性肿瘤之一 ,放射治疗是其主要的治疗手段 ,放疗后 5年生存率约为 43%～ 5 3%。随着病人生存时间的延长 ,晚期并发症逐渐出现 ,其中放射性脑病 (ＲａｄｉａｔｉｏｎＥｎｃｅｐｈａｌｏｐａｔｈｙ ,ＲＥＰ)是最为严重的并发症之一 ,这种损伤往往是不可逆转的 ,病情严重者极大地影响病人的生存质量和生存期。目前文献对ＲＥＰ系统报道较少。本文回顾性分析我院 2 9例鼻咽癌放疗后ＲＥＰ患者的临床和随诊资料 ,旨在探讨其发生、发展规律和预后结果。一、材料…     

鼻咽癌放射治疗后放射性脑损伤急性反应早期的1H-MR波谱研究

目的评价1H-MR波谱（1H-MRS）对鼻咽癌放射治疗（简称放疗）后放射性脑损伤急性反应早期的诊断价值.方法对18例已被病理证实且为首次行放疗的鼻咽癌患者进行前瞻性研究,于不同时间段对其双侧颞叶（共72个部位,颞叶前后部各为36处）进行常规MR和1H-MRS成像,成像时间为放疗前和放疗后接受放射剂量20Gy、40 Gy及60Gy时,成像序列为轴面SE T1WI、T2WI、T2液体衰减反转恢复序列（T2FLAIR）、三维扰相稳态梯度恢复采集T1序列（3D-SPGR T1＊）.以序列T2FLAIR或3D-SPGR T1＊为波谱成像的定位图,采用点分辨法进行多体素及单体素波谱成像,观察不同时间段颞叶各部位谱线的形态学改变及各代谢物间比值的变化.结果放疗后,双侧颞叶在常规MRI均未见明显信号改变,而在1H-MRS成像上,双侧颞叶前部谱线形态均有不同程度的改变,而颞叶后部无明显改变,表现为局部N-乙酰天门冬氨酸（NAA）峰和胆碱（Cho）峰降低,Cho/肌酸（Cr）、NAA/Cr及NAA/Cho比值在不同时间段均有下降;在接受放射剂量20Gy时,颞叶前叶有20处,占所有颞前叶的比例为56%（20/36）;40 Gy时有22处,占61%（22/36）;60Gy时有13处,占36%（13/36）.而谱线为NAA与Cho峰倒置在20Gy时,颞叶前叶有4处,占11%（4/36）;40 Gy时,有10处,占28%（10/36）;60 Gy时为23处,占64%（23/36）.与接受射线剂量呈明显正相关,不同剂量其同一比值差异有统计学意义（P＜0.05）.结论1H-MRS可在组织细胞代谢水平发现鼻咽癌放疗后急性反应早期的放射性脑损伤.     

Proton magnetic resonance spectroscopy of late delayed radiation-induced injury of the brain.

We prospectively evaluated metabolite changes in late delayed radiation-induced injury to the temporal lobes on proton ((1)H) magnetic resonance spectroscopy (MRS) in 34 patients. Morphologically more severe injury on imaging tended to have lower N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) ratios. A significantly higher Cho/Cr ratio was found in the most severe grade of cerebral necrosis, in which lactate might be present. The progressive decrease in NAA with increasing severity reflected neuronal loss at different stages of late delayed radiation-induced brain injury. The absence of Cho elevation in mild and moderate lesions did not suggest demyelination or glial hyperplasia as an etiologic mechanism of late delayed radiation-induced brain injury. The association of severe morphologic lesions with elevated lactate suggests ischemia as the underlying mechanism for severe lesions. (1)H MRS may provide metabolite information conducive to the understanding of the pathophysiology of late radiation-induced brain injury. J. Magn. Reson. Imaging 1999;10:130-137.     

Serial proton magnetic resonance spectroscopy of ischemic brain injury in humans

Four patients were observed serially with 1H magnetic resonance spectroscopy (MRS) at times ranging from 3 days to 10 weeks after a documented ischemic event. Spectra were obtained from 8 cc volumes in infarcted regions and contralateral matched normal regions. Reproducible variations in n-acetyl aspartate (NAA), creatine + phosphocreatine (Cr + PCr), and the sequential changes in lactate and lipid resonances are related to the pathophysiology of stroke. A conspicuous lack of significant change in the choline (Cho) resonance with concomitant decrease in NAA and Cr + PCr is reported as a possible marker of ischemic injury.     

质子磁共振波谱在脑损伤中的研究与应用

质子磁共振波谱(H-MRS)作为一种可以检测中枢神经系统生化代谢变化的无创性新技术,可广泛用于多种神经系统疾病的评价,本文就其在外伤性脑损伤(TBI)的研究和临床应用现状及进展作一综述。     

The clinical value of proton magnetic resonance spectroscopy in adult brain tumours

Proton magnetic resonance spectroscopy (1H MRS) non-invasively provides information on the biochemical profile (typically including up to nine metabolites and mobile lipids) of brain tissue, which varies according to the underlying disease process. A number of studies have assessed its accuracy in the diagnosis of adult brain tumours. This article describes the basic principles of 1H MRS, the metabolic profiles of different brain tumours, and practical points to aid interpretation of spectra. The literature is reviewed regarding the role of 1H MRS in the diagnosis of brain tumours and more specifically where it has proven to be of additional benefit over conventional magnetic resonance imaging.     

In vivo proton magnetic resonance spectroscopy of intraventricular tumours of the brain

The aim of this study was to assess the usefulness of proton MR spectroscopy in the diagnosis of intraventricular tumours. Fifty-two intraventricular tumours pertaining to 16 different tumour types were derived from our database. All cases had single-voxel proton MR spectroscopy performed at TE at both 30 and 136 ms at 1.5 T. The Mann-Whitney U test was used to search for the most discriminative datapoints each tumour type. Characteristic trends were found for some groups: high Glx and Ala in meningiomas (p < 0.001 and p < 0.01, respectively), high mobile lipids in metastasis (p < 0.001), high Cho in PNET (p < 0.001), high mI + Gly in ependymoma (p < 0.001), high NAC (p < 0.01) in the absence of the normal brain parenchyma pattern in colloid cysts, and high mI/Gly and Ala in central neurocytoma. Proton MR spectroscopy provides additional metabolic information that could be useful in the diagnosis of intraventricular brain tumors. Grants: This work was funded in part by MEDIVO2 (MEC SAF2005–03650), and Generalitat de Catalunya SGR2005–00863 and XT2004–51. CIBER-BBN is an initiative of “Instituto de Salud Carlos III” (ISCiii) of Spain.     

Monitoring the effects of mobile phone use on the brain by proton magnetic resonance spectroscopy

PURPOSE: To determine whether extensive use of mobile phones affects brain metabolites detectable by proton magnetic resonance spectroscopy (1H MRS). MATERIALS AND METHODS: Twenty-one extensive mobile phone users (average use = 5.5 +/- 2.2 years at 2.4 +/- 1.1 hours/day) and 15 control subjects were recruited and submitted to a 1H MRS brain examination at 1.5 Tesla. Data were recorded in the most exposed right temporal and pontobulbar areas as well as in the contralateral left temporal area. The ratios of N-acetylaspartate (NAA), choline (Cho) and myo-inositol (mI) to creatine/phosphocreatine (Cr) were measured. RESULTS: No statistically significant changes in the NAA/Cr, Cho/Cr and mI/Cr ratios were measured between mobile phone users and control subjects and between the exposed and contralateral temporal areas. CONCLUSION: These results indicate that extensive exposition to mobile phone radiation does not cause MRS-detectable brain metabolic changes.     

Phenylketonuria: diffusion magnetic resonance imaging and proton magnetic resonance spectroscopy

Two patients with phenylketonuria are reported with white matter lesions. Diffusion magnetic resonance (MR) imaging revealed restricted diffusion patterns (high signal) on b = 1000 s/mm2 images associated with low apparent diffusion coefficient values ranging between 0.44 x 10-3 mm2/s and 0.56 x 10-3 mm2/s. On proton MR spectroscopy obtained in 1 of the patients, a prominent peak resonating at approximately 3.80 ppm was consistently present attributable to the peak rising from the alpha-proton of the phenylalanine molecule.     

脑梗死~1H-MRS不同序列的对比研究

目的：探讨^1H-MRS在脑梗死患者脑内代谢物浓度差别及应用于脑梗死患者的优化序列参数。方法：对24例脑梗死患者脑内代谢物不同^1H-MRS序列进行对比研究，采用SPSS10．0统计分析软件，分组研究各主要代谢物的信噪比，半高度，相对浓度的差别，结果：脑梗死病灶与健侧之间NAA／Cho,Cho/Cr,Glx/Cr,Lac/Cr差异均有显著性意义（P＜0．05）；其中NAA／Cho,Lac/Cr差异有极显著意义（P＜0．01）。LacSNR25与136、25与272之间差异有显著性意义（P＜0．05）。结论：^1H-MRS可以较好地显示脑梗死病灶病理生理变化，短回波显示乳酸率高，但准确性低，长回波可将Lac与脂质分开。TE＝136、272ms为较佳参数条件。     

首发精神分裂症患者与正常人脑部质子波谱比较研究

目的：探讨首发精神分裂症患者与正常人脑部质子波谱检查结果。方法对收治的52例首发精神分裂症患者和接受健康体检的50例正常健康者分别进行 M RI常规检查和不同脑区1 H‐M RS检查。结果正常对照组在经过M RI检查后,未发现明显异常,而研究组患者中发现11例透明隔发育不良,7例脑白质或基底节区有异常小软化灶;2例脑室扩大。研究组患者前额叶背外侧回的NAA／Cr值和NAA／Cho值较正常健康者（对照组）明显下降,且差异具有统计学意义;而两组在Cho／Cr、MI／Cr、Glu‐Gln／Cr等项目上的比较则无明显差异（ t ＝1．55、1．02、1．88,P ＞0．05）。研究组患者海马区的NAA／Cr、NAA／Cho值较正常健康者（对照组）明显下降,且差异具有统计学意义;而两组在Cho／Cr、MI／Cr、Glu‐Gln／Cr等项目上的比较则无明显差异。研究组患者的BPRS中阴性评分总分与前额叶背外侧回代谢物NAA／Cr值呈现明显的负相关。结论首发精神分裂症患者与正常健康者在的1 HMRS检查结果方面的存在明显差异,提示精神分裂症存在神经元功能的异常,主要存在前额叶背外侧回和海马代谢异常。