磁敏感加权成像在脑胶质瘤术前分级的应用研究

目的 探讨磁敏感加权成像(SWI)用于脑胶质瘤术前分级的可行性及应用价值.方法 经病理诊断的脑胶质瘤患者36例,术前接受磁共振成像(MRI)常规序列(包括T1 WI、T2WI、T2-FLAIR及T1增强)扫描和SWI序列扫描,比较MRI常规序列、SWI序列进行分级的符合率.依据病理分级回顾性分析脑胶质瘤出血灶体积、肿瘤内血管数目SWI的检出情况,采用F检验及单因素方差分析数据.结果 SWI及MRI常规序列诊断与术后病理分级的符合率分别是75％和55.56％,SWI术前分级与病理符合率较高.在SWI,不同病理分级胶质瘤瘤内出血体积、瘤内小血管数目总体与肿瘤的恶性程度呈正比,胶质瘤瘤体内微出血体积、瘤内小血管数目在不同级别间差异有统计学意义.结论 脑胶质瘤的SWI序列图像上表现具有一定的特征性,SWI可作为MRI常规序列的补充用于脑胶质瘤的诊断和术前分级.     

DCE-MRI联合MTI在脑胶质瘤分级及浸润中的应用价值

目的 探讨动态对比增强磁共振成像(DCE-MRI)联合磁化传递成像(MTI)在胶质瘤分级中的应用价值.方法 搜集经病理证实的胶质瘤患者34例,其中高级别组(Ⅲ、Ⅳ级)20例,低级别组(Ⅰ、Ⅱ级)4例.所有患者均行颅脑常规MRI平扫及增强序列(T2WI、T1 WI、DWI、CE-T1 WI)和DCE-MRI和MTI序列(...     

多b值DWI对术前幕上胶质瘤分级的应用研究

目的：探讨何种 b 值扩散加权成像(DWI)对胶质瘤术前分级更有价值。方法回顾性分析经手术病理证实的38例胶质瘤(高级别24例、低级别14例)患者的 MRI 资料,均行常规 MRI 检查和3种 b 值的 DWI 检查(b=1000 s/mm2、2000 s/mm2、3000 s/mm2),分析 DWI 上肿瘤的信号特征,测量肿瘤最小表观扩散系数(ADC)值。对不同 b 值的肿瘤最小 ADC 值绘制受试者工作特征曲线(ROC),选取最佳诊断阈值,采用χ2检验分析不同序列的敏感性、特异性的差异。结果 b= 3000 s/mm2 DWI 图像上,91.6%(22/24)高级别胶质瘤呈高信号,85.7%(12/14)低级别胶质瘤呈低信号,以高信号作为诊断高级别胶质瘤的标准,诊断高级别和低级别胶质瘤的敏感性及特异性最高(91.6%和100%)。在 b 值相同时高级别胶质瘤的最小 ADC 值低于低级别胶质瘤,差异有统计学意义(P<0.05);3种 b 值鉴别高级别和低级别胶质瘤敏感性的差异有统计学意义(P<0.05),当以 ADC 3000<0.74×10-3 mm2/s 作为鉴别高级别胶质瘤的敏感性和特异性最高,分别为100%和87.3%。结论高 b 值 DWI 比常规 b 值 DWI 更能准确反映胶质瘤分级,应用 b=3000 s/mm2 DWI 肿瘤最小 ADC 值为胶质瘤术前更准确分级提供量化指标。     

基于多序列MRI影像组学模型预测脑膜瘤病理分级的价值

【摘要】目的：探讨基于多序列MRI影像组学模型预测脑膜瘤病理分级的价值。方法：回顾性分析经手术病理证实的215例脑膜瘤患者的临床及MRI资料。其中,低级别组174例,高级别组41例。将所有患者按照7∶3的比例随机分为训练组和验证组。采用ITP-SNAP软件,分别在T2WI、DWI和对比增强T1WI图像上勾画肿瘤的三维ROI,使用AK软件提取影像组学特征。采用Spearman相关性分析及多元Logistic回归分析筛选组学特征并构建影像组学标签。使用ROC曲线下面积（AUC）评价影像组学模型的预测效能。结果：高级别组与低级别组之间年龄和性别构成的差异均无统计学意义（P>0.05）。基于T2WI、DWI和对比增强T1WI的单序列及多序列联合影像组学模型预测高、低级别脑膜瘤的AUC均大于0.700。基于单序列的影像组学模型中,增强T1WI在训练组和验证组的AUC分别为0.942和0.913,均高于其它两个序列。基于MRI多序列联合的影像组学模型预测高、低级别脑膜瘤的AUC值最高,在训练组的AUC为0.950,在验证组的AUC为0.923。结论：MRI影像组学模型能够预测脑膜瘤的病理分级,尤其是多序列联合的影像组学模型对脑膜瘤病理分级具有较高的预测效能。     

SWI在胶质瘤分级中的应用价值

目的:探讨3.0TSWI在颅内胶质瘤分级中的应用价值。方法:经手术病理证实的20例高级别胶质瘤和12例低级别胶质瘤,均行T2WI、T2FLAIR、T1FLAIR、增强T1FLAIR和SWI。由2位经验丰富的神经影像学医师对SWI和常规MRI序列图像中肿瘤的内部结构进行盲法评定。观察项目包括:肿瘤内出血代谢物、钙化、肿瘤相关静脉的显示,并对病灶内低信号程度评分。结果:大多数低级别胶质瘤瘤内的细线状低信号提示血管结构,而大多数高级别胶质瘤瘤内斑片状及细线状低信号提示出血和血管结构。高级别胶质瘤低信号程度评分高于低级别胶质瘤,2组之间差异有统计学意义(Z=-3.308,P<0.01);胶质瘤级别与肿瘤低信号评分Pearson相关分析呈正相关(r=0.616,P<0.001)。结论:SWI有助于分析胶质瘤内部的细微结构及胶质瘤分级。     

颅内原发胶质肉瘤的MRI影像表现

目的分析颅内胶质肉瘤的MRI影像特征,以及这些影像特征在与颅内其他常见原发肿瘤鉴别诊断中的意义。资料与方法回顾性分析本院1998年4月至2011年4月9例经病理证实的胶质肉瘤患者的MRI影像表现、病理结果及临床表现。患者年龄30～66岁,平均48岁,所有患者均经手术切除及病理证实。9例患者均行常规T1WI、T2WI及增强扫描,部分患者行液体衰减反转恢复(FLAIR)、扩散加权成像(DWI)、扩散张量成像(DTI)及扩散张量纤维束成像(DTT)扫描。结果本组9例胶质肉瘤均发生在幕上。MRI平扫,肿瘤表现为边界清楚、均匀性或囊实性占位,伴有中重度水肿。T1WI上多呈低信号,T2WI上多呈高信号,FLAIR图像上,4例表现为高信号。增强扫描,多为明显环形强化。结论胶质肉瘤影像学表现具有一定特征,MRI能清晰显示病变,但与颅内其他原发肿瘤鉴别较困难,多序列成像有助于其鉴别诊断及预后的估计,确诊仍需病理检查。     

脑胶质瘤ESWAN图像定量参数的研究

目的 对比研究ESWAN图像中不同级别胶质瘤瘤内磁敏感信号（intratumoral susceptibility signal,ITSS）的相对信号强度（relative signal intensity,RSI）、ITSS最大径是否存在差异;评价MR各序列对显示ITSS的价值。方法 搜集30例胶质瘤患者的常规MRI及ESWAN图像,在Adw4.5工作站上应用Functol软件对ESWAN原始图像进行后处理得到幅值图,测取肿瘤内磁敏感伪影的最低信号强度、胼胝体压部的信号强度及肿瘤内磁敏感伪影的最大径;测量DWI（b=1 000）、T2WI及T2-FLAIR的ITSS最大径。将胶质瘤按照其病理结果分为I～Ⅱ级胶质瘤组,Ⅲ～Ⅳ级胶质瘤组。应用SPSS 17.0统计分析软件进行分析。结果 两组胶质瘤的RSI、ITSS最大径存在显著统计学差异;ESWAN,DWI,T2WI和T2-FLAIR序列显示ITSS的能力存在显著差异,且其敏感性依次降低。结论 ESWAN图像中ITSS的定量参数RSI及最大径有助于对胶质瘤的术前分级;ESWAN,DWI,T2WI和T2-FLAIR序列显示ITSS的能力依次降低。     

弥散MRI诊断颅内表皮样囊肿的价值

目的:探讨磁共振弥散加权成像(DWI)及表观弥散系数(ADC)图诊断颅内表皮样囊肿的价值.材料和方法:分析19例表皮样囊肿常规MRI和DWI的信号特征,定量测定表皮样囊肿、正常脑实质和脑脊液的ADC值.结果:17例表皮样囊肿T1WI、T2WI呈等或稍高于脑脊液信号,2例T1WI呈高低混杂信号.肿瘤边缘弧线形增强或不增强.19例肿瘤DWI呈明显高于脑实质和脑脊液信号,肿瘤较脑脊液的平均ADC值显著减低,较脑实质的平均ADC值显著增高.结论:DWI优于常规MRI发现颅内表皮样囊肿,DWI上表皮样囊肿的高信号可能是肿瘤组织的T2余辉效应所致.     

3.0TMRI高b值扩散加权成像在宫颈癌分期中的应用

目的：探讨3.0T MRI 扩散加权成像(DWI)单一序列在宫颈癌诊断及分期中的应用价值。方法2名观察者分别独立分析65例宫颈癌患者术前 T2 WI、DWI 和 LAVA-Flex 动态增强图像,比较三者对宫颈癌影像学分期结果的差异,对肿瘤的 T2 WI、DWI 和 LAVA-Flex 动态增强图像进行分期效能评估。结果DWI 检测到所有的病灶,其中3例病灶在常规 T2 WI 序列未能发现,1例在动态增强图像上未能发现。DWI、T2 WI 与 LAVA-Flex 动态增强对宫颈癌总体分期准确率分别为90.8%、78.5%、87.7%。DWI 单一序列分期的准确率高于单一 T2 WI 序列(P =0.04),DWI 序列与多期动态增强序列分期准确率无显著差异(P =0.39)。结论单一的 DWI 序列在宫颈癌分期中的准确性优于单一的 T2 WI 序列,在不具备增强的条件下 DWI 有望替代 MRI 动态增强序列,对宫颈癌做出准确的分期。     

颅内血管外皮细胞瘤MRI特征

目的 回顾分析颅内血管外皮细胞瘤(hemangiopericytomas,HPC)及脑膜瘤的MRI表现,以获得对颅内HPC的诊断及鉴别诊断具有价值的MRI特征.资料与方法 选取经病理证实的颅内HPC患者11例及脑膜瘤患者107例.用X2检验,Fisher确切概率法对比分析两组之间差异是否存在统计学意义.结果 颅内HPC的MRI 表现:肿瘤呈分叶状9例(81.8%),7例(63.6%)肿瘤以窄基底附着硬膜上,7例(63.6%)肿瘤内部呈迂曲的血管信号,8例(72.7%)肿瘤内囊变、坏死,7例(63.6%) T2WI呈等高信号,8例(72.7%)扩散加权成像(DWI)呈高信号;增强扫描肿瘤明显强化11例(100%),5例(45.5%)可见瘤周水肿.肿瘤形态(P<0.01)、肿瘤内部迁曲的血管信号(P<0.01),T2WI信号强度(P<0.05)及DWI信号强度(P<0.01)在两组之间差异有显著统计学意义.结论 颅内HPC的MRI表现具有一定特征性.肿瘤形态、T2WI及DWI信号、肿瘤内部迂曲的血管信号是鉴别颅内HPC及脑膜瘤的重要征象.     

Usefulness of diffusion/perfusion-weighted MRI in rat gliomas: correlation with histopathology

RATIONALE AND OBJECTIVES: Diffusion/perfusion-weighted MRI (DWI/PWI) can provide additional useful information in the diagnosis of patients with brain gliomas in a noninvasive fashion. However, the exact role of these new techniques is still undergoing evaluation. Our hypothesis was that DWI and PWI could be useful for assessment of growth and vascularity of implanted C6 rat gliomas. MATERIALS AND METHODS: Thirty-six rats were implanted with C6 glioma cells intracerebrally. Between 1 and 4 weeks after implantation, 8-10 rats were imaged on a clinical, 1.5-T whole-body magnetic resonance system with T(1)-weighted imaging (T(1)WI), T(2)-weighted imaging, DWI, PWI, and postcontrast T(1)WI at each weekly time point. All tumors were examined histologically; tumor cellularity and microvascular density were counted. RESULTS: On DWIs, statistical differences of apparent diffusion coefficient values for both the tumoral core and peritumoral region were present comparing tumors of 3-4 weeks' growth with tumors of 1-2 weeks' growth. Apparent diffusion coefficient value of tumoral core was negatively correlated with tumor cellularity (r = -0.682, P < .01). Statistical difference of maximal regional cerebral blood volume of tumoral core was present comparing 2-4 weeks with both 1 week after implantation and contralateral white matter (P < .01). Native vessel dilation in regions of normal brain at the periphery of the tumors at 1 week after implantation was observed. Correlation between maximal regional cerebral blood volume of tumor core and microvascular density was present (r = 0.716, P < .01). CONCLUSION: DWI and PWI has potential to characterize C6 gliomas in rats, which is a promising model similar to human gliomas.     

大鼠超急性期脑缺血的磁共振扩散加权成像研究

目的：利用磁共振扩散加权成像（DWI）评价大鼠超急性期脑缺血的诊断价值。方法：12只Wistar雄性大鼠,采用线栓法制作右侧大脑中动脉闭塞（MCAO）脑缺血模型,分别于栓塞后1h和6h行大鼠冠状位磁共振DWI、T2WI和T1WI检查,并测量缺血区DWI异常高信号的体积、表观扩散系数（ADC）值,将所测值进行比较。磁共振检查结束后处死大鼠,断头取脑行TTC染色,并与DWI结果进行比较。结果：大鼠MCAO后1h进行MRI扫描右侧大脑中动脉供血区DWI可见异常稍高信号,ADC为低信号,T2WI和T1WI均未见异常信号;MCAO后6hDWI可见明显高信号,较1hADC值显著减低（P〈0.01）,DWI上梗死灶体积显著扩大（P〈0.01）,T2WI显示缺血区异常高信号,T1WI可见稍低信号。TTC染色者均显示脑梗死灶,与MCAO后6h的DWI显示脑缺血范围一致。结论：DWI对超急性期脑梗死较常规MRI敏感,是超急性期脑缺血重要的检查方法。     

乳腺肿瘤MRI序列联合运用与微血管密度的对照研究

目的：探讨同一次检查中T2WI首次通过灌注成像及T1WI动态增强成像的联合应用在鉴别乳腺良恶性肿瘤方面的价值,并对所有病灶进行免疫组化CD34染色计数微血管密度进行评分,评价其相关性。方法：37例乳腺患者经手术或穿刺病理证实分为良恶性两组,经过MRIT2WI首次通过灌注成像后进一步行T1WI动态增强成像,对灌注及动态增强各参数进行分析,并与手术后病理图像及免疫组化结果对照。结果：乳腺肿块37例,乳腺癌21例,乳腺良性病灶16例,应用T2WI首过灌注成像,良恶性组早期信号强度丢失率之间重叠很少,敏感性为90%,特异性为75%;较T1WI动态增强组（敏感性47.6%,特异性为68.7%）提高;恶性组最大信号强度下降率与微血管密度MVD有明显正相关性（r=0.502,P〈0.05）,最大信号强度下降时间与微血管密度无明显相关性。良性组最大信号强度下降率、最大信号强度下降时间与微血管密度均无明显相关性。结论：乳腺癌T2WI灌注成像表现与病理特征相符,在乳腺癌血管生成的评价方面有重要价值。联合T2WI首次通过灌注成像及T1WI动态增强成像能够提高乳腺肿瘤的诊断特异性。     

表观弥散系数在高级别胶质瘤与急性期脑梗死鉴别诊断中的应用

目的探讨表观弥散系数(ADC值)在高级别胶质瘤与急性期脑梗死鉴别诊断中的应用。方法回顾性分析经手术和病理证实的18例高级别胶质瘤及正规及时溶栓治疗的28例急性期脑梗死的常规磁共振表现和弥散加权成像(DWI)表现,对照分析高级别胶质瘤实性部分、急性期脑梗死灶中心部分及对侧正常脑组织ADC值。结果 18例高级别胶质瘤患者共发现20个病灶,其中11例病灶内合并有出血、坏死和囊变,肿瘤实质部分呈稍高信号,囊变坏死区呈明显低信号,肿瘤实质部分平均ADC值为(0.92±0.12)×10-3mm2/s,对侧相应正常部位平均ADC值为(0.79±0.09)×10-3mm2/s,差异有统计学意义(P<0.05),急性期脑梗死在DWI上表现为高或稍高信号,其ADC值明显低于对侧相应区域,平均ADC值为(0.69±0.10)×10-3mm2/s,高级别胶质瘤实性部分与急性期脑梗死平均ADC值差异有统计学意义(P<0.05)。结论 DWI表现及ADC值对高级别胶质瘤与急性期脑梗死磁共振鉴别诊断具有重要价值。     

3.0TMR动态增强扫描及弥散成像联合应用诊断小肝癌的影像价值

目的分析小肝癌(SHCC)动态增强及弥散成像(DWI)(b值为600s/mm2)的信号特点并探讨二者联合应用的诊断价值。方法回顾性分析经病理证实的37例患者总共41个SHCC病灶的T1WI、T2WI、多期动态增强扫描及DWI的信号改变,并探讨T1WI、T2WI及动态增强(A组),T1WI、T2WI及DWI(B组)及这两种方法联合应用(C组)在SHCC的检出与定性诊断方面的价值。结果 SHCC以速升速降型强化方式为主(73.17%),强化峰值主要位于动脉晚期(75.61%);SHCC与周围肝组织的ADC值存在显著性差异;在病灶检出方面A组与C组的差异无统计学意义,而在病灶的定性诊断方面A组与C组的差异有统计学意义。结论肝脏多期动态增强扫描与弥散成像联合应用更有利于SHCC的定性诊断。     

Early detection of global cerebral anoxia: improved accuracy by high-b-value diffusion-weighted imaging with long echo time

BACKGROUND AND PURPOSE: Early and accurate detection of global cerebral anoxia is important for determination of prognosis and further management. We evaluated whether accuracy in early detection of global cerebral anoxia was improved by high-b-value diffusion-weighted imaging (DWI) with long echo time (TE). METHODS: Routine DWI (b = 1000 s/mm(2); TE = 139 ms), high-b-value DWI (b = 3000 s/mm(2); TE = 190 ms), T2-weighted imaging (T2WI), and fluid-attenuated inversion recovery (FLAIR) imaging were acquired in six patients who experienced cardiopulmonary arrest within 24 hours and six volunteers. Region of interest-based analysis was performed. Regions of interest of patients showing significant decrease in apparent diffusion coefficient (ADC) values than volunteers were considered abnormal. Three neuroradiologists independently assessed images of the patients for conspicuity of hyperintensity within regions of interest. Receiver operating characteristic (ROC) analysis was performed, and the area under the curve (Az) was compared among sequences and observers. Average contrast and contrast-to-noise ratios between abnormal regions of interest and regions of interest of normal surrounding parenchyma were calculated. RESULTS: For all observers, high-b-value DWIs achieved the largest Az, and FLAIR imaging the lowest Az. Az of routine DWI and T2WI were between these values. High-b-value DWI and FLAIR imaging showed no significant interobserver variation in Az, whereas routine DWI and T2WI did. High-b-value DWI also achieved the largest contrast and contrast-to-noise ratios. CONCLUSION: High-b-value DWI with long TE improved accuracy in early detection of global cerebral anoxia. Application of the sequence would facilitate early diagnosis.     

Diffusion-weighted MR imaging for the evaluation of seminal vesicle invasion in prostate cancer: initial results

PURPOSE: To evaluate the accuracy of T2-weighted (T2WI) with diffusion-weighted imaging (DWI) as compared with T2WI alone for predicting seminal vesicle invasion (SVI) of prostate cancer. MATERIALS AND METHODS: A total of 30 patients with SVI and 136 patients without SVI who underwent prostate MR imaging were included in the study. MR images were analyzed retrospectively and independently by two readers for SVI on T2WI and T2WI with DWI using a 5-point scale. RESULTS: For predicting SVI, the specificity for T2WI with DWI and for T2WI was 97% and 87%, respectively, and accuracy was 96% and 87%, respectively, as determined by the experienced reader (P < 0.01). For the less experienced reader, the specificity for T2WI with DWI and for T2WI was 96% and 81%, respectively, and accuracy was 90% and 77%, respectively (P < 0.01). The diagnostic performance of the less experienced reader with T2WI with DWI led to significant improvement of the area under the receiver operating characteristic curve (Az) as compared with T2WI alone (Az = 0.815 versus 0.696; P < 0.01). Interreader agreement showed a substantial agreement (kappa = 0.613) for T2WI, and a substantial agreement (kappa = 0.737) for T2WI with DWI. CONCLUSION: For predicting SVI, T2WI with DWI showed a better diagnostic performance than T2WI alone. Additionally, the accuracy of the less experienced reader using T2WI with DWI showed a significant improvement as compared with T2WI alone.     

不同病理分级儿童脑胶质瘤MR灌注成像

目的:采用磁共振灌注成像(MR PWI)探讨儿童不同级别脑胶质瘤的血流灌注特点及其临床诊断价值。方法:35例脑胶质瘤均经手术病理证实,其中Ⅰ～Ⅱ级胶质瘤(低级别胶质瘤组)28例,Ⅲ级胶质瘤(高级别胶质瘤组)7例,计算病灶内异常高灌注中心区(a区)、异常低灌注中心区(b区)、负性增强积分(NEI)伪彩图与T1WI增强图上不匹配区(c区)的相对NEI值(rNEI)及NEI伪彩图与T1WI增强图像上病变面积的比值(N/C),分析rNEI及N/C与肿瘤病理学分级的相关性。结果:高级别胶质瘤组中a区和c区的rNEI分别为8.39±1.91和5.43±0.52,均大于低级别胶质瘤组(分别为5.10±2.05和4.05±0.66),差异均具有极显著性意义(P<0.01)。高级别及低级别胶质瘤组NEI伪彩图上异常灌注区面积均大于T1WI增强图像上的异常强化区,N/C分别为1.06±0.11和1.45±0.09,差异具有极显著性意义(P<0.01)。结论:采用正确的研究方法MR PWI能有效分析儿童脑胶质瘤的血流灌注情况,对儿童脑胶质瘤的浸润范围的界定及术前分级均能有效判断。