DWI联合~1H-MRS诊断脑单发转移瘤

脑转移瘤（brain metastasis,BM）是指原发于身体其它部位的肿瘤转移至颅内。其发病率约占颅内肿瘤的20％。脑转移瘤多发于皮髓交界区,常以多发形式出现,脑内单发转移瘤与胶质瘤等较难鉴别。     

DWI在胶质瘤与单发转移瘤及其瘤周水肿中的诊断价值

目的:探讨DWI在颅内肿瘤及其瘤周水肿中的诊断价值和病理生理机制。材料和方法:分析ADC值在高级别胶质瘤和颅内单发转移瘤的病灶实质及水肿带中的改变(36例)。感兴趣区取病灶实质部分(病灶强化部分)及病灶周围水肿带(将水肿带三等份,分别作为近瘤周区、居中及远瘤周区水肿带),分别测定前述感兴趣区ADC值,测定对侧正常颞叶脑皮质ADC值作为参照值,测定相对ADC值(rADC值)作为分析指标。结果:转移瘤病灶实质及水肿带的ADC值均高于胶质瘤,即在DWI图上前者与后者相比为稍低信号,两者水肿带间ADC值有显著差异。胶质瘤居中水肿带ADC值最低,低于近瘤周区及远瘤周区水肿带,有统计学差异。转移瘤居中水肿带ADC值稍低于近瘤周区及远瘤周区水肿带,但无统计学差异。结论:转移瘤病灶实质及水肿带ADC值均高于胶质瘤。胶质瘤水肿带成因除血管源性水肿之外,尚有部分原因为瘤细胞的浸润所致,肿瘤细胞阻碍了水分子的运动,此点有助于术前在DWI上鉴别两种肿瘤。     

DWI和~1H-MRS在肝纤维化中的诊断价值

目的:探讨扩散加权成像(DWI)与氢质子波谱分析(1 H-MRS)在肝纤维化中的诊断价值。方法:使用腹腔注射CCl4溶液法诱导建立兔肝纤维化模型并进行DWI和1 H-MRS检查。DWI使用SE-EPI序列(b1=0s/mm2,b2=600s/mm2),1 H-MRS使用单体素点分辨波谱分析(PRESS)序列(TR 1500ms,TE 35ms),测量表观扩散系数(ADC)值及胆碱(Cho)和脂质(lipid)波峰下面积的比值(Cho/lipid)。以病理学肝纤维化分期为基础,将兔划分为无肝纤维化组(S0)、轻度-中度纤维化组(S1-S2)和重度纤维化及肝硬化组(S3-S4),比较不同组间ADC值和Cho/lipid变化规律。结果:随肝纤维化程度加重,ADC值依次降低(P<0.01),Cho/lipid依次升高(P<0.05);重度纤维化及肝硬化组与另两组ADC值及Cho/lipid差异均具有统计学意义(P均<0.05)。结论:DWI和1 H-MRS具备一定的定量肝纤维化及检测重度纤维化及肝硬化的能力。     

DWI在恶性胶质瘤和单发脑转移瘤鉴别中的应用研究

恶性胶质瘤和单发脑转移瘤有着相似的临床及常规影像学表现,是临床诊断及鉴别诊断一难点。由于两者治疗方法不同,准确的诊断及鉴别诊断对治疗方法的选择和病人的预后有重要作用。DWI能够反映活体组织水分子的扩散信息,能定量分析组织的微观结构和功能改变,在一定程度上可反映肿瘤的细胞密度、核浆比及瘤周浸润情况,在脑肿瘤诊断上已经获得越来越多的认可。就扩散加权成像在恶性胶质瘤和单发脑转移瘤鉴别中的应用予以综述。     

肺癌脑转移瘤的常规MR、DWI 及MRS诊断价值

目的:总结肺癌脑转移病灶的常规MRI表现,并对其中部分病例行DWI和(或)MRS检查,以提高对肺癌脑转移的认识.材料和方法:回顾性分析经我院检查确诊的肺癌脑转移病例共177例,接受常规MRI序列检查.手术病理或临床病史证实的32例肺癌脑转移瘤病例,临床处理前接受DWI和(或)2D1H-MRS检查.分析其弥散及波谱表现特征,分别测定肿瘤实质、坏死/囊变部分、瘤周水肿部分及正常脑实质ADC值,以及Cho/Cr、NAA/Cr、NAA/Cho等代谢比率.结果:病灶强化方式以环状和结节状为主.环形强化的特征为外壁光滑,内壁毛糙,壁厚薄不均匀,强化不均.肿瘤实质部分ADC值为1.08±0.37×10mm2/s,囊变部分ADC值为2.5±0.36×10mm2/s.与瘤周水肿区及正常脑实质ADC值有显著差异性.肿瘤实质部分Cho峰多降低,CR峰降低,NAA峰多测不到.肿瘤组织与瘤周水肿区及正常脑实质的代谢比率(Cho/Cr)有显著差异性,而瘤周水肿区与正常脑实质的代谢比率无明显差异.结论:肺癌脑转移MRI强化主要表现为环形强化和结节状强化,环形强化有一定的特征表现可与其他病变鉴别.其在弥散及波谱图像上有一定的特点,与常规MRI序列结合可明显提高诊断准确性.     

扩散加权成像在高分化胶质瘤和转移瘤中的鉴别价值

目的探讨扩散加权成像（DWI）在高分化胶质瘤与转移瘤中的应用与鉴别价值。方法搜集经临床和手术确诊的16例胶质瘤（Ⅰ～Ⅱ级）和18例转移瘤，采用Philips Gyroscan Intera 1．5T超导MR系统进行常规扫描和DWI。住分析常规图像和DWI图像基础上，进行肿瘤灶（包括肿瘤囊变区、实性组织、瘤周带、瘤周水肿4部分）的表观扩散系数（ADC）值测量，并进行统计学分析。结果16例胶质瘤主要表现为单发不规则长T1、T2信号，有10例伴有不同程度的囊性变，12例伴有小同程度瘤周水肿，10例行增强扫描显示病灶强化程度不一，7例呈轻度强化，2例无明显强化，1例中度强化。转移瘤中3例单发，15例多发，DWI可检测（直径均〉1．5cm，可以进行较准确的ADC值测量）的病灶为48个，其中，囊性转移灶5个，囊实性转移灶20个，实性转移灶13个，伴有瘤内出血4例10个病灶。转移瘤主要表现为长T1、T2信号，伴出血时可表现出短T1、T2信号，其中11例增强扫描主要显示为环形或不规则边缘强化。ADC值测量结果显示胶质瘤组较转移瘤组的瘤周带ADC值有明显增高（t=4．455，P〈0．01），而两组间在肿瘤实性和囊性组织以及瘤周水肿带的ADC值测量方面差异无统计学意义（P〉0．05）。结论转移瘤由于生长迅速，可能形成瘤周“致密带”，产生相应的压迫效应，从而导致瘤周ADC值较高，此征象可能成为胶质瘤与转移瘤之间的鉴别特点。     

MRS联合多b值DWI对高级别胶质瘤与单发脑转移瘤的鉴别诊断价值

【摘要】目的：探讨氢质子磁共振波谱（1H-MRS）联合多b值磁共振扩散加权成像（DWI）的多参数值对术前幕上单发大脑高级别胶质瘤（HGG）与单发脑转移瘤（MET）的鉴别诊断价值。方法：选取术前常规MRI检查考虑为幕上单发的HGG或MET的住院患者,对其进行1H-MRS及多b值DWI成像,利用后处理软件重建波谱图及各b值对应的ADC图,分别于各肿瘤瘤体区、瘤周区及对应正常脑质的合适层面勾画兴趣区（ROI）,分别记录其平均Cho/NAA值、Cho/Cr值、 NAA/Cr值及ADC值,最终满足纳入标准的有49例（经手术病理或临床随访证实HGG 24例,MET 25例）。采用独立样本t检验（正态分布）或Mann-Whitney U检验（非正态分布）比较两组间各参数差异性,绘制受试者操作特征（ROC）曲线分析各参数鉴别HGG与MET的诊断效能。利用二元logistic回归分析得到两种技术联合鉴别HGG与MET的预测概率,然后绘制ROC曲线分析MRS、多b值DWI及两种技术联合三种方法鉴别两种肿瘤的诊断效能。结果：瘤周区平均Cho/Cr值为MRS鉴别两者的最佳参数,其曲线下面积（AUC）为0.936,敏感度为90%,特异度为87%。当b=1000s/mm2时相应的瘤周区ADC值为DWI鉴别两者的最佳参数,其AUC为0.863,敏感度为87%,特异度为78.9%。联合两种技术的最佳鉴别参数,即瘤周区平均Cho/Cr值和b=1000s/mm2时相应的瘤周区ADC值,绘制ROC曲线分析MRS、高b值ADC值及两种技术联合鉴别两者的诊断效能,发现两种技术联合时AUC最大,为0.973,敏感度为86.4%,特异度为100%。结论：1H-MRS联合多b值DWI对两种肿瘤的鉴别诊断效能优于其中任一成像技术的鉴别诊断效能。     

增强后多体素^1H-MRS对脑胶质瘤、单发转移瘤和脑脓肿的鉴别诊断价值

目的：探讨注射对比剂后多体素^1H-MRS对脑胶质瘤、单发转移瘤和脑脓肿的鉴别诊断价值。方法：搜集脑胶质瘤16例、单发转移瘤19例和脑脓肿6例,均行注射对比剂后多体素^1H-MRS检查。10例年龄匹配的健康志愿者作对比。比较脑胶质瘤与单发转移瘤强化区及强化边缘区胆碱／肌酸（Cho／Cr）、氮-乙酰天门冬氨酸／胆碱（NAA／Cho）、氮-乙酰天门冬氨酸／对侧相应正常脑组织区胆碱（NAA／Cho-n）和胆碱／对侧相应正常脑组织区胆碱（rCho）值的差异,并做统计学分析。结果：各个级别胶质瘤与单发转移瘤强化区之间Cho／Cr值分别为3．1709±2．197和4．3520±2．509,NAA／Cho-n值分别为0．3312±0．301和0．3843±0．223,差异均无统计学意义（P〉0．05）;而NAA／Cho值分别为0．2436±0．220和0．4550±0．240,rCho值分别为1．5426±0．808和0．9129±0．304,差异均有统计学意义（P〈0．05）;强化边缘区之间上述比值分别为Cho／Cr1．6208±0．230和0．9105±0．414,NAA／Cho-n 0．5357±0．250和0．8015±0．374,NAA／Cho 0．4762±0．278和2．4434±1．636,rCho1．1761±0．423和0．5405±0．497,除NAA／Cho-n外差异均有显著统计学意义（P〈0．001）。脑脓肿出现特征性波谱。结论：增强后多体素^1H-MRS对脑胶质瘤、单发转移瘤和脑脓肿的鉴别诊断有重要的临床应用价值。     

高级别星形细胞瘤与脑单发转移瘤的1H MRS鉴别

目的 :探讨活体1 HMRS对高级别星形细胞瘤和单发转移瘤的鉴别诊断价值。方法 :搜集行1 HMRS检查的高级别星形细胞瘤 2 5例 (包括间变型星形细胞瘤 11例 ,胶质母细胞瘤 14例 ) ,单发转移瘤 10例。比较两组肿瘤强化区及肿瘤周围区之间Cho/Cr、NAA/Cr及Lac/Cr值。结果 :2 5例高级别星形细胞瘤与 10例单发转移瘤强化区的Cho/Cr分别为 5 .770 0± 1.82 12及 4.45 0 0± 2 .42 5 0 ,NAA/Cr分别为 0 .9476± 0 .5 0 2 6及 1.185 0± 0 .5 63 7,Lac/Cr分别为 2 .4684± 1.710 5及 3 .2 110± 2 .70 77,两组之间差异均无显著性意义 (P >0 .0 5 )。而肿瘤瘤周区的Cho/Cr分别为 2 .3 3 0 0± 1.2 10 0及1.0 75 0± 0 .2 5 41,差异具有显著性意义 (P <0 .0 0 1) ;NAA/Cr及Lac/Cr之间差异无显著性意义。结论 :应用1 HMRS检测肿瘤周围区代谢水平的高低可作为鉴别高级别星形细胞瘤和单发转移瘤的补充手段     

MR弥散、灌注、波谱成像在单发脑转移瘤与恶性胶质瘤鉴别诊断中的价值

目的探讨磁共振弥散加权成像(DWI)、灌注加权成像(PWI)和1H波谱(1H-MRS)检查在单发脑转移瘤与恶性胶质瘤鉴别诊断中的应用价值。方法对术前进行了磁共振DWI、PWI和MRS检查并经病理证实的18例单发脑转移瘤和16例恶性胶质瘤进行回顾性分析,测量各病灶瘤体区、瘤周区及对照区的ADC、rCBV及Cho/Cr、Cho/NAA、NAA/Cr值,并计算rADC及rrCBV。结果瘤灶区rADCT单发脑转移瘤与恶性胶质瘤之间没有统计学差异(P>0.05),瘤周区rADCP脑转移瘤高于恶性胶质瘤,分别为1.98±0.69及1.43±0.31(P<0.05);瘤灶区rrCBVT和瘤周区rrCBVP转移瘤均低于恶性胶质瘤,分别为1.07±0.62、2.68±1.22(P<0.05)和0.38±0.23、1.11±0.61(P<0.05);瘤灶区Cho/Cr、Cho/NAA、NAA/Cr值脑转移瘤与恶性胶质瘤之间差异均无统计学意义;瘤周区胶质瘤Cho峰高于脑转移瘤,Cho/Cr和Cho/NAA值均高于脑转移瘤,分别为2.25±0.75、1.91±0.40和1.31±0.15、0.96±0.32(P<0.05和P<0.0...     

Differentiation between high-grade glioma and metastatic brain tumor using single-voxel proton MR spectroscopy

The purpose of this study was to clarify the efficacy of single-voxel proton magnetic resonance spectroscopy (MRS) in differentiating high-grade glioma from metastasis. Thirty-one high-grade gliomas (11 anaplastic gliomas and 20 glioblastomas) and 25 metastases were studied. Proton MRS was performed using point-resolved spectroscopy with echo times (TEs) of both 136 and 30 ms. The peaks for lipid were evaluated at short TE, and those for N-acetyl-aspartate (NAA), creatine (Cr), and choline-containing compounds (Cho) were assessed at long TE. All the tumors exhibited a strong Cho peak at long TE. Twenty-one of 25 metastases showed no definite Cr peak. The remaining 4 metastases showed NAA and Cr peaks; however, the presence of NAA and relatively high NAA/Cr ratio (1.58+/-0.56) indicated normal brain contamination. All the gliomas, except for a single glioblastoma, showed a Cr peak with (n=16) or without (n=14) NAA. At short TE all metastases and glioblastomas showed definite lipid or lipid/lactate mixture, but anaplastic gliomas showed no definite lipid signal. Intratumoral Cr suggests glioma. Absence of Cr indicates metastasis. Definite lipid signal indicates cellular necrosis in glioblastoma and metastasis, and no lipid signal may exclude metastases.     

Diagnostic value of proton MR spectroscopy and diffusion-weighted MR imaging in childhood inherited neurometabolic brain diseases and review of the literature

The purpose of this study is to evaluate parenchymal diffusion properties and metabolite ratios in affected brain tissues of inherited neurometabolic brain diseases with an overview of the current literature about the diagnostic data of both techniques in childhood inherited metabolic brain diseases. The study group was consisting, 19 patients (15 males, 4 females; mean age, 54 months (4.5 years); age range, 1-171 months (14.25 years)) diagnosed with inherited neurometabolic brain disease. Single- and multivoxel proton MRS was carried out and NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr ratios were calculated. Presence of lactate peak and abnormal different peaks were noted. ADC values were calculated from brain lesions. Results are compared with age and sex matched normal subjects. Elevated NAA/Cr ratio (Canavan disease), galactitol peak (galactosemia) at 3.7 ppm, branched chain amino acids (Maple syrup urine disease—MSUD) at 0.9 ppm were seen on different diseases. In Leigh disease and MSUD restricted diffusion was detected. Different diffusion properties were seen only in one Glutaric aciduria lesions. NAA/Cr ratios and calculated ADC values were significantly different from normal subjects (p < 0.05). DWI combined with MRS are complementary methods to routine cranial MRI for evaluating neurometabolic diseases which can give detailed information about neurochemistry of affected brain areas.     

大脑胶质瘤病磁共振成像结合磁共振波谱成像的诊断价值

目的：探讨磁共振成像（MRI）结合磁共振波谱成像（MRS）对大脑胶质瘤病的诊断价值。方法对15例经活体组织检查或手术病理证实的大脑胶质瘤病患者的临床表现及MRI平扫、增强,MRS影像学资料进行回顾性分析。MRI常规行T1WI、T2WI及FLAIR序列,采用时间飞跃法（TOF）的磁共振血管成像（MRA）,T1WI增强扫描。氢质子MRS采用单体素STEAM序列,并分析N-乙酰天门冬氨酸（NAA）、肌酸（Cr）、胆碱复合物（Cho）等物质峰值改变。结果所有病例均侵犯2个或2个以上脑叶,以颞叶、枕叶、胼胝体、基底节和丘脑等部位侵犯受累常见。病变区T1WI呈低或等低信号、T2WI呈高或混杂高信号、FLAIR上为高信号,未见明显坏死、钙化,受累区域脑组织肿胀,占位效应轻。注射钆喷酸葡胺增强扫描示10例无明显强化、3例斑片状强化、1例结节状强化、1例线状轻度强化。病变区域MRS表现为不同程度NAA降低,NAA/Cr比值降低;Cho上升,Cho/Cr和Cho/NAA的比值上升。结论 MRI结合MRS对大脑胶质瘤病的诊断及鉴别诊断具有临床价值,是目前诊断大脑胶质瘤病的首选影像学方法。     

扩散加权成像对良恶性淋巴结鉴别的研究进展

淋巴结转移与否对于癌症病人的预后、分期及治疗方案的选择极为重要。目前常规MRI依靠淋巴结大小鉴别其良恶性的准确性不高,利用MR功能成像方法鉴别淋巴结良恶性是目前影像学研究的热点。其中扩散加权成像相较其他方法具有诸多优点。近年来非高斯模型包括双指数模型、拉伸指数模型、扩散峰度模型等逐渐应用于临床。现就传统及非高斯模型扩散加权成像在淋巴结良恶性鉴别上的研究现状及价值予以综述。     

"Prominent ear sign" on diffusion-weighted magnetic resonance imaging in relapsing polychondritis

Relapsing polychondritis is a rare autoimmune disease characterized by recurrent inflammation of cartilage in multiple sites of the body, including the auricles. Central nervous system involvement appears rare. We encountered a case of relapsing polychondritis with encephalitis that could be diagnosed by the unique appearance of the auricle with signal hyperintensity on diffusion-weighted magnetic resonance imaging.     

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.     

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.     

Extracranial applications of diffusion-weighted magnetic resonance imaging

Diffusion-weighted MRI has become more and more popular in the last couple of years. It is already an accepted diagnostic tool for patients with acute stroke, but is more difficult to use for extracranial applications due to technical challenges mostly related to motion sensitivity and susceptibility variations (e.g., respiration and air-tissue boundaries). However, thanks to the newer technical developments, applications of body DW-MRI are starting to emerge. In this review, we aim to provide an overview of the current status of the published data on DW-MRI in extracranial applications. A short introduction to the physical background of this promising technique is provided, followed by the current status, subdivided into three main topics, the functional evaluation, tissue characterization and therapy monitoring.     

颅内胶质瘤和转移瘤的磁共振波谱和弥散成像研究

目的:探讨颅内胶质瘤和转移瘤肿瘤强化区域和肿瘤周围区域的1H-MRS和弥散成像特点及其对于鉴别诊断的意义。方法:34例颅内肿瘤患者(其中低级别胶质瘤Ⅰ～Ⅱ级10例,高级别胶质瘤Ⅲ～Ⅳ级13例,转移瘤11例)均行常规MRI,DWI,多体素MRS检查。DWI的观察指标是ADC值;MRS主要观察的代谢物有:氮-乙酰天门冬氨酸(NAA),胆碱复合物(Cho),肌酸(Cr/PCr),计算NAA/Cr,Cho/Cr,NAA/Cho比值。采用SPSS10.0软件进行统计学比较。结果:①DWI的检查结果:低级别胶质瘤肿瘤强化区域的ADC值较另外两者高,且有统计学意义;高级别胶质瘤肿瘤周围区域的ADC值最低,与另外两者有显著差异。其余之间没有统计学意义;②MRS的检查结果:高级别胶质瘤和转移瘤肿瘤强化区域各比值之间没有显著差异(P>0.05),且二者与低级别胶质瘤相比有显著差异性(P<0.05);高级别胶质瘤肿瘤周围组织出现NAA/Cr与NAA/Cho降低,Cho/Cr升高,且与转移瘤和低级别胶质瘤肿瘤周围组织相比均有显著差异性(P<0.05)。结论:结合肿瘤强化区域与肿瘤周围区域的磁共振波谱和DWI可以对胶质瘤和转移瘤起到鉴别诊断作用。     

Vertebral body metastasis of glioblastoma multiforme with epidural mass formation contrast enhanced MRI study

A 35-year-old woman with left frontoparietal glioblastoma was subtotally resected twice and 1 year later demonstrated extracranial metastasis. Magnetic resonance imaging (MRI) demonstrated metastasis to the first thoracic vertebral body with epidural and paravertebral extension. Bone scintigrams of the spine appeared normal. The mechanisms and radiological findings of the extracranial metastasis of an astrocytic glioma are reviewed.