线粒体脑肌的MRI表现特征及其诊断价值

目的:总结线粒体脑肌病的MRI表现特征并分析磁共振在线粒体脑肌病诊断中的价值。方法:搜集2005年1月～2007年7月经临床及病理证实的线粒体脑肌病患者资料21例,男5例,女16例。所有病例均行常规MRI检查(平扫加增强扫描),7例患者行磁共振波谱检查。结果:21例中有17例患者脑内病灶均表现为T1WI低信号、T2WI高信号,病变主要累及颞、顶、枕叶皮层、及深部灰质核团(以基底节多见),部分患者伴有不同程度的脑萎缩,病灶对称或不对称,且具有多发性,迁移性和与血管分布区不一致性;4例患者头部常规扫描仅见轻度脑萎缩。FLAIR及DWI序列能更清楚和准确显示较隐匿的病灶,7例磁共振波谱检查表现为病变区、无信号异常的脑区和/或脑室系统均可见较特征性的乳酸峰。结论:线粒体脑肌病的MRI表现有一定的特征性,磁共振成像(包括DWI、FLAIR、MRS)在线粒体脑肌病的诊断、鉴别诊断以及对该病代谢物改变的检测方面均具有重要的价值。     

DWI、MRS和CASL-PWI联合应用在MELAS型线粒体脑肌病诊断中的价值

目的 明确扩散加权成像(DWI)、磁共振波谱成像(MRS)和连续动脉自旋标记(CASL)灌注成像(CASL PWI)等无创性检查的联合应用在线粒体脑肌病伴乳酸血症和卒中样发作(MELAS)诊断中的应用价值.资料与方法 2例MELAS患者,除了常规MRI检查序列,补充了DWI、MRS和CASL-PWI.结果 在MELAS急性期,DWI显示病灶呈略低信号,MRS显示乳酸峰升高,在看似正常的脑组织中乳酸峰亦轻度升高.CASL-PWI显示病灶为高灌注.结论 通过DWI、MRS和CASL-PWI等无创性检查联合应用对于MELAS有极大诊断价值,并且可以鉴别MELAS急性期与脑梗死急性期.     

脑脱髓鞘性假瘤的磁共振成像表现

目的探讨脑脱髓鞘性假瘤的磁共振成像表现,提高对该病的磁共振(MR)诊断水平。方法回顾性分析2例均行常规MRI检查、氢质子磁共振波谱成像(1H-MRS)及脑灌注成像,并与病理结果对照,总结脱髓鞘性假瘤的MRI特点。结果 2例患者均为青年男性,急性起病入院,MRI表现为T1WI高低混杂信号,T2WI高信号,1H-MRS为NAA峰降低,胆碱(Cho)峰升高,并出现乳酸(Lac)和胶质(Lip)峰,MR灌注成像(PWI)示脑血流量、脑血容量降低,平均通过时间及峰值时间延长。结论脑脱髓鞘性假瘤常规MRI表现具有一定特征性,联合功能成像有助于作出正确诊断。     

线粒体脑肌病卒中样病灶的磁共振诊断及波谱分析

目的 探讨线粒体脑肌病伴高乳酸血症与卒中样发作事件(MELAS)脑内卒中样病灶的磁共振成像表现及~1H磁共振波谱特征.方法 回顾分析7例MELAS患者的临床及磁共振检查资料.结果 本组病例所行12次磁共振检查共计评价超急性期卒中样病变12个、急性期病灶12个、亚急性10个和慢性病灶6个.MELAS脑内卒中样病灶最初表现为局限大脑皮层的水肿信号灶,可累及皮层下区,多发于颞、枕、顶叶.磁共振扩散加权成像,病变在超急性期(3 d内)表现为以细胞毒性水肿为主,呈边界清楚的高信号灶;急性期(4～7 d)、亚急性期(2～4周)至慢性期(＞4周)病变逐步扩大,边界变模糊,以血管源性水肿为主.~1H磁共振波谱分析,脑卒中样病变在早期以高耸的双乳酸峰为特点,伴N-乙酰天门冬氨酸(NAA)等脑代谢物成分不同程度降低;随后,乳酸峰逐步降低,NAA等代谢物浓度可部分恢复.结论 MELAS卒中样病灶主要累及大脑皮层和皮层下区,细胞毒性水肿出现早但持续时间短,~1H磁共振波谱以典型的双乳酸峰为特征并伴有NAA浓度降低.     

磁共振波谱技术在乳腺癌诊断中的应用

目的:利用氢质子磁共振波谱(1H MRS)技术检测活体乳腺癌病灶与对侧正常乳腺组织内的物质代谢和物质生化含量的差异及其反映在分子水平上的病理改变。方法:对30例经乳腺钼靶摄影疑为一侧乳腺癌的患者行1H MRS检查,比较其病侧与对侧相应部位正常腺体组织的胆碱(Choline,Cho)、乳酸(Lactine,Lac)含量有无显著性差异。结果:正常乳腺组织1H MRS在1.32ppm处显示一独立清晰的乳酸峰,胆碱峰显示低平,Cho峰顶与Lac峰顶的连线呈上升趋势。30例病侧组在3.2ppm处Cho峰显著增高,Lac峰明显降低,Cho峰顶与Lac峰顶的连线呈下降趋势;两组间行秩和检验,差异有显著性(P<0.05)。结论:氢质子磁共振波谱(1H MRS)对于乳腺癌的定性诊断可提供有价值的辅助信息。     

线粒体脑肌病综合影像表现

目的:探讨多种影像技术对线粒体脑肌病(ME)的诊断价值.方法:回顾性分析7例线粒体脑肌病患者的影像资料,其中7例行常规MRI扫描,3例行MRA扫描,4例行MRS扫描,1例行DSA检查,6例行CT平扫.结果:6例病变主要累及两侧大脑皮层和皮层下,1例主要表现为白质内改变,均表现为长T1、长T2改变;MRA示2例未见明显改变,1例示病变处血管分支明显增粗;4例MRS在病变处检出乳酸双峰,1例在脑脊液中检出乳酸双峰.1例行DSA检查示病灶内血管分支增粗,血运加快.6例行CT检查病灶均呈低密度改变.结论:影像检查尤其是MRI检查对ME的诊断提供了丰富的信息,当年青患者出现非典型性脑梗死表现,MRS检出乳酸双峰时要考虑到线粒体脑肌病的可能.     

成人线粒体脑肌病的MRI和1H-MRS诊断价值

目的 分析MRI和1H-MRS对线粒体脑肌病的诊断价值.方法 经病理活检确诊的 6例成人 (男3例,女3例)线粒体脑肌病患者采用1.5T磁共振仪扫描,其中3例行1H-MRS检查,并分析MRI和1H-MRS的表现. 结果6例线粒体脑肌病患者MRI显示病变累及多个脑叶,多位于皮层及皮层下白质,并可同时累及大脑深部灰质和大脑皮层.脑梗死样病灶呈斑片状或楔形,非对称性.T1WI为低信号或等低信号,T2WI为高信号.急性期病变区域脑组织轻度肿胀,慢性期全脑萎缩,并可见皮质层状坏死.4例行MR增强扫描未见强化.3例1H-MRS检查均显示病灶内Lac峰明显升高和NAA峰不同程度的降低.结论 线粒体脑肌病MRI表现具有一定的特征,1H-MRS可提供更多脑组织代谢信息,对本病诊断具有重要的价值.     

MRI在小儿线粒体脑肌病中的诊断价值

目的　探讨MRI在小儿线粒体脑肌病中的诊断价值。方法　搜集自 1996 -0 1～ 2 0 0 0 -12经MRI检查、病理及实验室检查证实的小儿线粒体脑肌病 16例进行回顾性分析。结果　 16例患者脑内病灶均表现为多发对称性略长T1、长T2 信号 ,其中单纯脑深部灰质受累 9例 ,大脑皮质和深部灰质同时受累 4例 ,灰、白质同时受累 2例 ,单纯白质受累 1例。结论　多样化的临床和MRI表现是小儿线粒体脑肌病的特点 ;MRI对小儿线粒体脑肌病的诊断有较大帮助。     

~1H-MRS在脑胶质瘤中的诊断价值

目的探讨氢质子磁共振波谱(~1H-MRS)诊断脑胶质瘤的价值。方法回顾分析5例经手术病理证实脑胶质瘤患者的影像资料。结果~1H-MRS术前诊断4例,诊断准确率80%。5例患者均行单体素及多体素氢质子脑波谱成像,MRS示5例患者中,NAA峰3例明显降低,1例中度降低,1例轻度降低;Cho峰3例明显升高,2例轻度升高;Cr峰4例下降不明显或轻度下降,1例明显下降;1例可见Lip峰;1例可见Lac峰。3例Ⅲ~Ⅳ级胶质瘤瘤体实质区表现NAA峰明显降低,Cho峰明显升高,Cr峰下降,1例出现Lip峰。结论~1H-MRS从微观分子水平分析脑胶质瘤的生化代谢信息,是对传统MRI形态解剖学成像的有力补充,~1H-MRS对脑胶质瘤的术前诊断、分级有重要的临床价值。     

^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。     

Serial proton magnetic resonance spectroscopy in lesions of Balò concentric sclerosis

OBJECTIVE: Balò concentric sclerosis is a rare demyelinating disorder. Serial proton magnetic resonance spectroscopic (1H-MRS) studies were carried out to better understand the biochemical changes within concentric lesions. MATERIALS AND METHODS: Five concentric lesions in four patients with Balò concentric sclerosis were chosen as the objects of serial observation. They included two early acute lesions (showing as concentric ring enhancement on magnetic resonance imaging (MRI) after gadolinium administration), two late acute lesions (showing as marginal enhancement on MRI), and one early subacute lesion (showing as edematous concentric lesions without enhancement on MRI). The duration of follow-up ranged from 2-23 months (mean 10 months). A total of 20 1H-MRS studies were performed. On each 1H-MRS study, short-echo (30 ms) and long-echo (136 ms) spectra were obtained. The peaks of N-acetyl-asparate (NAA), choline-containing compounds (Cho), creatine and phosphocreatine (Cr), lactate, and mobile lipid were observed and compared. RESULTS: Generally, a decrease of NAA/Cr ratio and an increase of Cho/Cr ratio were seen on all the spectra. Observing longitudinally, a trend of decreasing NAA/Cr ratio first and then partially recovering later was noted. The lowest level of NAA/Cr ratio was noted at the late acute stage or early subacute stage. The Cho/Cr ratio and amplitude of the lactate peak showed a similar trend as that of NAA/Cr, but in an opposite direction. It was rising first and descending later. The highest levels of Cho/Cr ratio and lactate peak were also observed at the late acute or early subacute stage. In addition, lactate peaks could be detected as long as 7 months after onset of symptoms. Lipid metabolite (two broad peaks at 0.9-1.5 ppm) was seen at the initial study of each group, but fluctuated in size on follow-up. CONCLUSION: The characteristic biochemical changes of concentric sclerosis were a decreased NAA/Cr ratio, an increased Cho/Cr ratio, two broad peaks at 0.9-1.5 ppm, lactate production, and a reversible NAA/Cr ratio on follow-up. The serial 1H-MRS studies revealed a strong biochemical association between NAA, Cho, and lactate, which may be caused by the same pathogenetic process of demyelination and inflammatory cellular infiltration. The specificity of the serial changes may provide information about the stage of the concentric lesion and perhaps aid in monitoring progression of concentric lesions and evaluating therapy.     

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.     

~1H-MRS磁共振波谱分析对海马硬化诊断的评价

目的分析原发性颞叶癫痫与海马硬化之间的关系,探讨磁共振波谱成像(1H-MRS)在海马硬化早期诊断中的应用价值。方法回顾性分析30例经手术证实的海马硬化患者的临床表现、1H-MRS资料,重点分析1H-MRS的NAA、Cr、Cho波峰特点。结果 1H-MRS发现异常28例(93%),2例在MRI及1H-MRS均未见异常。结论 1H-MRS可对海马硬化或伴有海马胶质细胞增生者进行早期诊断,提高了海马硬化诊断的敏感性。     

Lactate, choline, and creatine levels measured by vitro 1H-MRS as prognostic parameters in patients with non-small-cell lung cancer

PURPOSE: To determine the biochemical characteristics of lung cancer tissue using in vitro (1)H-MRS, and investigate the correlation between survival probabilities and lactate (Lac), creatine (Cr), and choline (Cho) concentrations measured by in vitro (1)H-MRS. MATERIALS AND METHODS: A total of 21 patients with lung cancer were included in this retrospective study. (1)H-MRS spectra measurements were performed at 6.35T using a JNM-EX270, high-resolution FT-NMR spectrometer. RESULTS: When normal lung tissue was compared with lung cancer tissue, significant differences were noted most consistently in the levels of Lac and Cho, with lung cancer tissue showing higher values than normal lung tissue. Lac concentrations of lung cancer tissue were significantly higher in patients with recurrence compared to patients without recurrence (0.285 +/- 0.096 mumol/g). The mean overall survival of patients in the low-Lac group was 50.28 +/- 6.47 months, which is significantly higher compared to the high-Lac group, which had a mean survival time of only 30.49 +/- 5.41 months. CONCLUSION: Kaplan-Meier analysis of the data showed that the overall and disease-free survival probabilities were significantly higher in patients with low tumor Lac values than in those with high tumor Lac concentrations.     

颞叶癫痫定位诊断的磁共振波谱研究

目的:探讨氢质子磁共振波谱(1H-MRS)对颞叶癫痫(TLE)定位诊断的应用价值.方法:选择15例经手术和病理证实的TLE患者和15例性别、年龄与之相匹配的健康志愿者为研究对象,分别作双侧颞叶内侧的1H-MRS,并对双侧海马区域进行精确定位,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)的浓度进行相对定量分析.结果:采用Kappa检验,两位医师对海马硬化诊断的一致性K值=0.80(P＜0.05),表明一致性很好,MRI可对10例患者作出术前定位.MRS示TLE患侧组NAA/(Cho Cr)为0.37±0.07,对照组和TLE对侧组则分别为0.65±0.07和0.62±0.18,差异有显著性意义(F值为23.170,P＜0.05);MRS定位准确12例,另3例为阴性,结合MRI可对13例准确定位.结论:1H-MRS能敏感地探测到神经元的异常改变,为颞叶癫痫的术前定位提供了一种新的检查方法,其与MRI相结合可提高术前定位的准确率.     

Brain abscess and necrotic brain tumor: discrimination with proton MR spectroscopy and diffusion-weighted imaging

BACKGROUND AND PURPOSE: Discriminating pyogenic brain abscesses from cystic or necrotic tumors is sometimes difficult with CT or MR imaging. We compared findings of proton MR spectroscopy ((1)H-MRS) with those of diffusion-weighted imaging to determine which technique was more effective for this differential diagnosis. METHODS: Fourteen patients (necrotic or cystic tumor [n = 7]; pyogenic abscess [n = 7]) who underwent 1.5-T (1)H-MRS and diffusion-weighted imaging and had findings of ring-shaped enhancement after contrast agent administration were enrolled in this study. Diffusion-weighted imaging was performed with a single-shot spin-echo echo-planar pulse sequence (b = 1000 s/mm(2)). The apparent diffusion coefficient and ratio were also measured. RESULTS: Spectra for two patients were unacceptable because of either poor shimming conditions or contamination from neighboring fat. Spectra in three of five patients with abscess had lactate, amino acids (including valine, alanine, and leucine), and acetate peaks; one of the three spectra had an additional peak of succinate. In one patient with abscess treated by antibiotics, only lactate and lipid peaks were detected. Spectra for four of seven patients with cystic or necrotic tumors showed only lactate peaks. Lactate and lipids were found in three patients with tumors. Hyperintensity was seen in all the pyogenic abscess cavities and hypointensity in all the cystic and necrotic tumors on diffusion-weighted images. CONCLUSION: (1)H-MRS and diffusion-weighted imaging are useful for differentiating brain abscess from brain tumor, but the latter requires less time and is more accurate than is (1)H-MRS. (1)H-MRS is probably more limited in cases of smaller peripheral lesions, skull base lesions, and treated abscesses.     

原发性中枢神经系统淋巴瘤的MRI与~1H-MRS研究

目的:探讨免疫功能正常人原发性中枢神经系统淋巴瘤(PCNSL)的常规MRI及多体素质子磁共振波谱(1H-MRS)表现。方法:对15例经病理证实的PCNSL的MRI和1H-MRS表现进行回顾性分析。结果:15例患者共检出24个病灶,其MRI及1H-MRS表现如下:①PCNSL的MRI表现:病灶T1WI呈低或等信号,T2WI呈等或稍高信号;DWI呈高信号;增强后病灶明显均匀强化,"缺口征"、"尖角征"的出现具有特异性;②PCNSL的1H-MRS表现:肿瘤实质区及瘤周近侧水肿区Cho峰升高及NAA、Cr峰降低,肿瘤实质区可见升高的Lip峰。4例病灶在正常组织区可见异常谱线。结论:传统MRI结合1H-MRS表现能够显著提高PCNSL的诊断与鉴别诊断水平;1H-MRS对于肿瘤浸润及多发病灶的显示优于传统MR检查。     

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.     

Improved analysis of 1H-MR spectra in the presence of mobile lipids.

Focal brain lesions can be associated with proton magnetic resonance spectra (1H-MRS)-detectable mobile lipids, reflecting severe tissue degradation and necrosis. However, advanced fitting procedures, such as the LCModel, fail to adequately fit spectra in the presence of lipid resonances. To overcome this, different approaches to generate lipid model spectra were compared using a phantom, real in vivo data, and simulated data. Twenty-six in vivo short-echo time (TE) 1H-MRS from 21 malignant gliomas, four infections, and one ischemia were analyzed to evaluate the performance of the modified LCModel fit. Adding simulated aliphatic resonances at 1.3 and 0.9 ppm improved the overall fitting quality remarkably and allowed good separation of lactate and alanine. Also, a better differentiation of glioblastomas and anaplastic gliomas was achieved. In conclusion, we propose a simple way to efficiently include lipid resonances in the LCModel, allowing a better fit of in vivo short-TE 1H-MRS, and demonstrate the diagnostic potential of quantitative assessment of mobile lipids in brain tumors.     

Comparison of conventional and diffusion-weighted MRI and proton MR spectroscopy in patients with mitochondrial encephalomyopathy,lactic acidosis,and stroke-like events

The mechanism of neurological disturbances in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is controversial. We studied 12 patients with MELAS using conventional and diffusion weighted MRI (DWI) and MR spectroscopy (MRS), to look at the physiopathology of the stroke-like events. Although conventional MRI showed lesions in all patients, DWI was more sensitive. One patient did not show high signal on DWI 48 h after a from stroke-like episode, but MRS demonstrated a lactate peak in left occipital lobe; 2 weeks after the attack, high signal was demonstrated on the right frontal lobe where MRS had shown a lactate peak. Our findings suggest a possible predictive ability of ¹H-MRS, in showing early MELAS lesions and supports the hypothesis that mitochondrial metabolic dysfunction may precedes abnormalities on DWI.