功能磁共振成像在脑肿瘤诊断中的应用

功能磁共振成像是一种新的影像学检查方式，主要包括弥散加权成像、灌注加权成像及血氧水平依赖成像三种成像方法。同以往影像学检查只能依赖于被检查组织形态学的改变不同，弥散加权成像主要研究脑组织内水分子的弥散情况，灌注加权成像主要研究脑组织血液动力学的情况，而血氧水平依赖成像则可对脑内的重要功能区进行准确定位。所以，功能磁共振成像可对人脑在生理和病理状态下的脑功能活动进行有效的评价，可准确地对肿瘤进行早期诊断、区别肿瘤组织成分、预测肿瘤恶性程度及为临床提供治疗方案。本文主要综述脑功能磁共振成像方式的基本原理及主要临床应用，以提高临床工作者对此项检查技术的认识。     

磁共振扩散加权成像在头颈部肿瘤放化疗中的应用价值

磁共振扩散加权成像作为目前唯一能无创性在活体观察水分子自由扩散运动的功能成像,不仅用于头颈部疾病的诊断和鉴别诊断,还在头颈部肿瘤的疗效评价和预测等方面具有潜在优势。本文就磁共振扩散加权成像在头颈部肿瘤放化疗中的应用价值作一综述。     

功能磁共振在食管癌应用的研究进展

目的：近些年,功能影像技术发展迅速,寻找一种准确可靠、价格合理且适宜临床推广的影像学技术成为当前研究的热点。本研究总结国内外功能磁共振成像技术在食管癌中的应用,探讨功能磁共振在食管癌诊断、治疗中的价值。方法应用 PubMed 及 CNKI 期刊全文数据库检索系统,以“食管癌、功能磁共振、磁共振动态增强、磁共振弥散加权和磁共振波谱”为关键词,检索2000-01－2015-01的中英文文献,纳入标准：（1）功能磁共振在食管癌诊断中的应用;（2）功能磁共振在食管癌疗效评价中的应用;（3）功能磁共振在食管癌预后评估中的应用。符合分析的文献56篇。结果功能磁共振在食管癌中的应用涉及磁共振动态增强成像、磁共振弥散加权成像和磁共振波谱成像,其中磁共振动态增强和磁共振弥散加权成像通过对组织血流灌注特征及水分子运动特征的分析,可用于早期评估肿瘤组织新生血管生成情况、放化疗疗效及预后,磁共振波谱成像可从分子水平上反映离体肿瘤组织生化代谢信息,在体研究仍需大量的前瞻性实验获取可靠的数据。结论功能磁共振在食管恶性肿瘤的诊断、疗效判断、预后评估中应用价值明显。     

脑部放疗对血脑屏障的影响

血脑屏障可以使中枢神经系统有选择地从血液中吸收所需生理活动物质,但它对颅内肿瘤或感染的治疗药物是一种障碍,临床上能透过血脑屏障渗入脑实质的只有BCNU和CCNU类型药物。 新生的血管没有脑屏障功能,用泛影葡胺作血管造影或脑CT扫描时,肿瘤部位造影剂浓集密度最高,显示新生的肿瘤区血管通透性强,没有屏障功能。本文探讨放射治疗对血脑屏障的作用。     

多模态脑功能定位在胶质瘤中的临床应用

目的:探讨术前多模态磁共振弥散张量成像（diffusion tensor imaging，DTI）脑功能定位技术在脑胶质瘤手术中的应用价值。方法:选择2016年1月至2017年3月在我院接受手术治疗的25例脑胶质瘤患者作为研究对象，所有患者术前均利用核磁共振DTI技术在导航工作站将肿瘤、神经纤维束及肿瘤周边的结构进行重建，并进行3D打印，术前根据3D打印出来的模型进行模拟手术，术中避开重要结构切除肿瘤，手术入路设计上可以避免损伤脑功能区及肿瘤周边的重要结构，通过多模态定位技术进行脑胶质瘤手术。结果:术前导航定位准备工作13～19 min，平均（15.2±1.4） min；iMRI扫描准备时间4～7 min，平均（5.8±0.8） min。25例患者全切21例，占84％；次全切或部分全切4例，占16％。术后KPS评分与术前相比较显著升高（P<0.05）。术后1年生存23例，生存率92％。结论:术前多模态磁共振DTI脑功能定位技术用于脑胶质瘤的手术治疗可通过影像融合和重建，提供准确的肿瘤与功能区结构的关系，准确显示肿瘤位置，为肿瘤的精准切除提供了保障。     

磁共振功能成像在脑肿瘤诊断中的应用

目前,MRI因软组织分辨率高、无辐射及多平面成像等优势已成为脑肿瘤疾病的一种常规检查手段。近年来,随着磁共振技术的发展及磁场强度的增加,一些新的MR功能成像技术已开始越来越多的应用于临床,如磁共振波谱、脑功能成像、灌注成像、磁敏感加权成像、弥散张量成像等,主要用于脑肿瘤之间及脑肿瘤与非肿瘤性疾病的鉴别、肿瘤的分级、指导外科术式的选择、放疗方案的制订等。     

磁共振技术评价头颈部肿瘤放疗后涎腺功能的应用及进展

口干是头颈部肿瘤放疗后最常见且最突出的晚期反应之一,当前各种检测涎腺功能的手段都有一定的不足。磁共振涎管成像（magnetic resonance sialography,MRS）和扩散加权磁共振成像（diffusion-weighted magnetic resonance imaging,DW MRI）是近年新发展起来的涎腺功能评价方法,具有无创、无辐射的特点。本文就该技术在涎腺功能评价方面的应用进展作一综述,为探讨头颈部肿瘤患者放疗前后涎腺功能变化监测手段的发展方向提供参考。     

多模态MRI在高级别脑胶质瘤放疗中的应用

放疗是高级别脑胶质瘤治疗的重要手段之一。目前,对于利用定位CT和常规MRI图像进行靶区勾画的范围仍然没有统一标准。随着影像学技术的不断发展,研究者们发现利用多模态MRI包括氢质子磁共振波谱分析(¹H-MRS)、BOLD-fMRI (血氧水平依赖性功能磁共振)、弥散加权成像(DWI)、弥散张量成像(DTI)等可更有效地评估肿瘤的浸润范围及定位周围重要组织,从而作为一种补充手段应用于靶区勾画和保护危及器官之中。此外,多模态MRI对评估放疗疗效、探测放射损伤及鉴别真假性进展也有一定作用。文章就多模态MRI在高级别脑胶质瘤术后放疗中应用作一综述。     

肿瘤与止血的相互作用——血小板抑制剂和抗凝剂应用于肿瘤治疗的理论基础

临床和实验研究表明,某些肿瘤在体内能激活血小板和凝血机制,血小板和纤维蛋白会参与肿瘤的生长和转移。对血小板抑制剂和抗凝剂作为肿瘤辅助治疗的效果,已经或正在进行大量的临床和实验研究。对不同的药物和肿瘤,抗血小板药物可产生不同的效果。宿主和肿瘤两者的前列腺素合成途径似乎是血小板功能抑制剂起作用的重要因素。在试验的各种抗凝剂中,香豆素衍生物对某些人类和实验性肿瘤能产生较为一致的抗肿瘤效果。口服抗凝剂的抗肿瘤效果看来不是药物的直接作用,似与其作为维生素K拮抗剂有关。应当强调,尽管     

磁共振新技术在肿瘤诊断中的应用

ＭＲＩ（磁共振）具有无创伤性、多层面扫描、参数灵活、反映组织特性敏感、分辨力高等优点 ,ＭＲＩ成像技术已广泛用于临床肿瘤的诊断、鉴别诊断、疗效评定及放疗定位 ,兹分述近年来部分ＭＲＩ新技术在肿瘤诊断中的应用如下。１头部颅内肿瘤的准确分级和完整评价对治疗方案的选择具有重要意义 ,目前肿瘤血流体积（ｒｃＢｖ）的测定 ,动态增强ＭＲ成像以及瘤内磁感伪影的显示对脑胶质细胞瘤的分级有较大的帮助 ,研究结果已与肿瘤的病理组织学分级有较好的相关性［１］。快速成像对脑磁共振成像具有深远影响 ,平面回波成像技术（ｅｃｈｏｐｌ…     

Functional MRI in clinical practice: A pictorial essay

In clinical practice, functional magnetic resonance imaging (fMRI) is a valuable non‐invasive tool particularly during preoperative work‐up of brain tumour and epilepsy patients. In this pictorial essay, we review expected areas of eloquent cortical activation during the four major clinical paradigms, discuss pitfalls related to fMRI and look at clinical examples where fMRI was particularly valuable in preoperative planning.     

The role of diffusion tensor imaging in establishing the proximity of tumor borders to functional brain systems: implications for preoperative risk assessments and postoperative outcomes

Diffusion Tensor Imaging (DTI) is a new MRI imaging technique sensitive to directional movements of water molecules, induced by tissue barriers. This provides a new form of contrast that allows the identification of functional white matter tracts within the brain, and has been proposed as a technique suitable for presurgical planning in brain tumor patients. Resection of primary brain tumors improves survival, functional performance, and the effectiveness of adjuvant therapies, provided that surgically-induced neurological deficits can be avoided. Diffusion Tensor Imaging (DTI) has the potential to establish spatial relationships between eloquent white matter and tumor borders, provide information essential to preoperative planning, and improve the accuracy of surgical risk assessments preoperatively. We present our experience in a series of 28 brain tumor patients where the integration of functional magnetic resonance imaging (fMRI) and DTI data was used to determine key anatomic spatial relationships preoperatively. Twice as many functional systems were localized to within 5 mm of tumor borders when DTI and fMRI were utilized for preoperative planning, compared to that afforded by fMRI alone. Our results show that the combined use of fMRI and DTI can provide a better estimation of the proximity of tumor borders to eloquent brain systems sub-serving language, speech, vision, motor and premotor functions. Additionally, a low regional complication rate (4%) observed in our series suggests that preoperative planning with these combined techniques may improve surgical outcomes compared to that previously reported in the literature. Larger studies specifically designed to establish the accuracy and predictive value of DTI in brain tumor patients are warranted to substantiate our preliminary observations.     

Les applications de l’IRM fonctionnelle en neuro-oncologie

Over the last decade, functional magnetic resonance imaging (fMRI) has become a useful, complementary tool in the presurgical evaluation of numerous brain diseases. In clinical practice, fMRI is commonly used to map eloquent sensorimotor and speech-related areas before surgical resection of brain tumours. fMRI also provides insights into brain perfusion and oxygenation changes in response to vasomotor agents. An evaluation of cerebrovascular reactivity is in progress.     

Cognitive function and breast cancer: promise and potential insights from functional brain imaging

Altered cognitive function can be a distressing side effect of cancer and its treatment. Women diagnosed and treated for breast cancer often report problems with memory, concentration, and other cognitive abilities that can pose significant barriers to full resumption of family, job, and social roles. Despite considerable neuropsychological research, many unanswered questions remain about cancer-related cognitive deficits and the underlying neural bases. Functional magnetic resonance imaging (fMRI) measures brain activation associated with different mental states and has significantly advanced our understanding of cognitive function and dysfunction in healthy and clinical populations. However, to date the application of fMRI to the study of cognitive function in breast cancer is limited. The current review addresses the potential importance of this method for understanding the neurocognitive effects of breast cancer disease and treatment. Along with reviewing published fMRI studies on breast cancer to date, we discuss potential major contributions of this method which include: (a) delineating components of cognitive function and underlying neural processes most affected by cancer and its treatment, (b) uncovering compensatory processes and their limits, (c) identifying altered resting state networks that may relate to subjective complaints and longer term outcomes, and (d) clarifying the relationship between pre-treatment alterations in brain activity and longer term neural and behavioral outcomes. Finally, we pose questions for future research that can be optimally addressed by integrating fMRI and other imaging modalities to clarify the nature and causes of “chemo brain” and guide interventions to improve cognitive function and the quality of breast cancer survivorship.     

Demonstration of paramagnetic and diamagnetic cerebral lesions by using susceptibility weighted phase imaging (SWI)

Susceptibility-weighted MR imaging (SWI) has become a non-invasive diagnostic modality for functional MR imaging (fMRI) of the brain and also for the imaging of tumors, injuries, malformations or microhemorrhages. SWI often enables detection of otherwise subtle abnormalities or provides additional relevant information when combined with routine MR imaging. The purpose of this article is to illustrate the potential of SWI in the discrimination of paramagnetic and diamagnetic brain lesions in neuroradiological applications.     

Effects of androgen deprivation on brain function in prostate cancer patients ¿ a prospective observational cohort analysis

ABSTRACT: BACKGROUND: Despite a lack of consensus regarding effectiveness, androgen deprivation therapy (ADT) is a common treatment for non-metastatic, low-risk prostate cancer. To examine a particular clinical concern regarding the possible impact of ADT on cognition, the current study combined neuropsychological testing with functional magnetic resonance imaging (fMRI) to assess both brain activation during cognitive performance as well as the integrity of brain connectivity. METHODS: In a prospective observational cohort analysis of men with non-metastatic prostate cancer at a Veterans Affairs medical center, patients receiving ADT were compared with patients not receiving ADT at baseline and at 6 months. Assessments included fMRI, the N-back task (for working memory), the stop-signal task (for cognitive control), and a quality of life questionnaire. RESULTS: Among 36 patients enrolled (18 in each group), 30 completed study evaluations (15 in each group); 5 withdrew participation and 1 died. Results for the N-back task, stop-signal task, and quality of life were similar at 6 months vs. baseline in each group. In contrast, statistically significant associations were found between ADT use (vs. non use) and decreased medial prefrontal cortical activation during cognitive control, as well as decreased connectivity between the medial prefrontal cortex and other regions involved with cognitive control. CONCLUSIONS: Although ADT for 6 months did not affect selected tests of cognitive function, brain activations during cognitive control and functional brain connectivity were impaired on fMRI. The long-term clinical implications of these changes are not known and warrant future study.     

功能磁共振成像在神经外科应用的初步经验

背景与目的：位于脑中央沟附近的肿瘤在外科手术中易造成运动功能损伤。本研究拟运用功能磁共振成像（functional magnetic resonance imaging,fMRI）的方法术前确定手运动功能皮层的位置及其与肿瘤的关系。探索fMRI在神经外科的应用价值。方法：31例位于中央沟附近的脑肿瘤患者接受常规和功能磁共振检查,其中转移瘤10例,胶质瘤11例,脑膜瘤6例,动静脉畸形2例,蛛网膜囊肿2例。功能成像方法采用在手静止和开合运动中,行快速梯度平面回波连续成像,以平行胼胝体前后联合的连线为基线,连续16层,层厚为4mm,层距为零,共获得1280幅功能原始图像,并经处理获得统计学Z-score图。结果：除2例患者头运动较明显外。其余患者都显示了手运动功能皮层活化兴奋区。并测得了功能皮层区与肿瘤的最短距离。功能皮层活化区表现出3种不同类型,包括：病灶内或边缘散在的活化小斑点;功能皮层活化区受挤压、移位;功能皮层活化区形态,位置正常。此外,在其他区域亦出现了不同例数的活化现象。结论：fMRI能帮助确定中央沟附近的脑肿瘤与手运动功能区位置的关系,从而为外科手术提供参考。     

fMRI结合术中皮层电刺激在语言区附近肿瘤切除中的临床研究

  目的  探讨功能磁共振(functional magneticresonance imaging, fMRI)联合术中直接皮层电刺激(electrical corticalstimulation, ECS)技术在定位患者语言功能区中的作用及其临床应用价值。   方法  术前利用fMRI技术, 定位Broca或Wernicke区, 术中唤醒麻醉下采用ECS定位语言功能区, 与术前fMRI定位结果对比, 语言功能区保护下显微切除肿瘤。   结果  10例语言功能区附近肿瘤的患者中, 在术中唤醒麻醉下采用ECS定位语言功能区成功8例, 与术前fMRI结果对比, 6例为重叠, 2例为邻近关系。   结论  fMRI可以作为语言功能区附近肿瘤术前无创伤性、个体化定位的一种有效方法, fMRI与术中ECS的联合应用能够实现可视化保护语言功能的同时最大化地切除肿瘤组织, 从而提高了患者的术后生活质量, 具有良好的临床应用价值。      

Functional MR imaging of working memory before neurosurgery

Information concerning the tissue adjacent to a brain tumour is crucial for planning and performing a neurosurgical intervention. In this study, we evaluated the usefulness of functional imaging of working memory in terms of working memory preservation. Working memory performance of 14 patients with prefrontal tumours was tested preoperatively by means of a standardized neuropsychological test battery. Also, functional magnetic resonance imaging (fMRI) using a so-called two-back paradigm was performed to visualize brain areas related to that task. Working memory areas were reliably detected in all patients. Surgery was then planned on the basis of this information, and the data were used for intra-operative cranial neuronavigation. Three to twelve months after surgery, patients were tested again with the test battery in order to detect possible changes in working memory performance. In 13 cases the memory performance was unchanged, only one female patient had a slight impairment of working memory compared to the pre-operative status.     

Real-time 3 T fMRI data of brain tumour patients for intra-operative localization of primary motor areas

Introduction

In patients with tumours in or near the motor cortex reliable intra-operative identification of the precentral gyrus can be difficult due to anatomical dislocation. Maps of functional magnetic resonance imaging (fMRI) based on the blood oxygen level dependent (BOLD) effect are used to localize eloquent functional areas of the brain but require postprocessing for reduction of false positive activations. We set the focus of this study on the evaluation of feasibility and clinical usefulness of using real-time fMRI t-maps without postprocessing for pre-operative planning and intra-operative localization of functional motor areas.

Methods

Real-time fMRI t-maps from a 3-T MRI scanner were coregistered with MRI data. Ten patients were operated under general anaesthesia using 3D neuronavigation with integrated real-time fMRI t-maps. Surgical and functional outcome was compared to results of 12 patients who previously underwent wake surgeries.

Results

Good neurological outcome was achieved in all treated patients. Main activation clusters on fMRI real-time maps were easily identified. Coregistered real-time fMRI data without additional postprocessing were useful in planning the surgical approach. However, due to brain shift and large voxel size of BOLD contrast signals on t-maps exact localization of borders between tumours and functional areas was not possible intra-operatively.

Conclusion

Our method is very simple to use and effective in guiding the neurosurgeon safely through minimally invasive craniotomies to tumours in eloquent areas without setting lesions to functional areas. Furthermore, the neurosurgeon is more independent when tumour location requires acquisition of fMRI data for pre-operative planning and intra-operative navigation.