磁共振成像新技术在新生儿缺氧缺血性脑病中的应用

缺血缺氧性脑病(HIE)是新生儿常见病,可引起早期死亡,继发脑瘫、智力低下、癫日等神经系统症状.MRI技术被公认为是诊断新生儿 HIE 及评估神经损害程度最有价值的影像学方法.尤其近年来,新的MRI技术如扩散加权成像、灌注成像、磁共振波谱、扩散张量成像及磁敏感成像等技术的快速发展,使 MRI 不仅可以观测HIE的形态学变化特点,而且可以反映HIE的病理过程及分子学变化.针对MR常规技术及新技术在新生儿缺血缺氧性脑病中的应用研究及进展作一综述.     

MRI在宫颈癌诊断和治疗效果评估中的应用价值

MRI是宫颈癌术前确定分期的最佳影像学手段，扩散加权成像及灌注成像在评价肿瘤复发、监测放疗效果中发挥重要作用。     

MRI在宫颈癌诊断和治疗效果评估中的应用价值

MRI是宫颈癌术前确定分期的最佳影像学手段,扩散加权成像及灌注成像在评价肿瘤复发、监测放疗效果中发挥重要作用.     

磁共振成像新技术在肝脏局灶性病变诊断中的应用

肝脏病变在临床上是一种常见病。MRI技术被认为是诊断肝脏病变最有价值的影像学方法。尤其近年来,新的MRI技术如扩散加权成像、灌注加权成像、波谱成像、弹性成像等技术的快速发展,使MRI不仅用于观察肝脏病变的形态变化特点,而且可以反映肝脏病变的病理过程及分子学的变化。针对MRI新技术在诊断肝脏局灶性病变中的应用及进展进行综述。     

前列腺癌MRI诊断技术研究进展

前列腺癌是世界上第二常见的男性恶性肿瘤, 我国前列腺癌的发病率亦呈逐年上升趋势。MRI有着良好的软组织分辨率及多方位成像优势, 能较好地显示前列腺的解剖结构及相邻的组织结构, 随着MRI技术的不断发展, 其对前列腺癌的诊断发挥着越来越重要的作用。该文从前列腺癌MRI常规序列的影像表现着手, 对各种功能MRI在前列腺癌的诊断和鉴别诊断中的应用进行了详细地论述, 如MR灌注加权成像、MR波谱、MR扩散加权成像、MR扩散张量成像、体素内不相干运动扩散加权成像、MR磁敏感加权成像等, 介绍了功能MRI相对于常规扫描的优势及其所能提供的更多的影像学资料, 通过系列半定量和定量数据, 能进一步提供前列腺癌的血流灌注、水分子扩散、微循环状态、物质代谢及生化成分变化等信息。     

MRI在子宫肉瘤和子宫肌瘤鉴别诊断中的应用进展

子宫肉瘤与子宫肌瘤的治疗方案和预后管理完全不同,对两者的鉴别诊断至关重要。MRI是诊断子宫肿瘤的重要影像方法,尤其是扩散加权成像（DWI）、扩散张量成像（DTI）、扩散峰度成像（DKI）、灌注加权成像（PWI）、MR波谱成像（MRS）、增强梯度回波T₂*加权血管成像（ESWAN）等功能MRI及影像组学,在子宫良恶性肿瘤鉴别、病理分型分级和分子变化等方面可以进行量化分析,从而提供更多有价值的信息。就MRI在鉴别子宫肉瘤和子宫肌瘤中的应用进展作一综述。     

同时多层成像技术联合肝脏MR扩散成像的应用及展望

同时多层（SMS）成像技术与多种MRI序列联合应用可明显缩短成像时间。MR扩散成像,如常规扩散加权成像（DWI）、体素内不相干运动成像（IVIM）、扩散张量成像（DTI）和扩散峰度成像（DKI）能反映组织内水分子扩散、血流灌注、组织结构复杂性等微观特征,在肝脏病变检测和辅助定性中有重要价值。SMS与MR扩散成像联合后可明显缩短成像时间,利于各种MR扩散成像在肝脏中的广泛应用。综述SMS对肝脏扩散成像扫描速度的提升效率、对影像质量和定量参数的影响,以期推动SMS成像技术在临床中的广泛应用。     

新生儿缺氧缺血性脑病的磁共振扩散加权成像

目的:探讨MR扩散加权成像(DWI)在足月新生儿缺氧缺血性脑病(HIE)的应用价值。方法:以9例无窒息史的健康新生儿作对照,对临床确诊的46例HIE患儿(轻度15例,中度11例,重度10例)行常规MRI及DWI检查,并对比分析。结果:DWI发现HIE脑损伤的敏感度为26%(12/46);DWI显示HIE所致脑梗死优于常规MRI。对于弥漫性对称性脑损伤病变,1例病程在1天以内者,DWI显示病变范围较T2WI更广泛;病程较长者,DWI低估病变范围及程度。重度HIE组双侧顶叶白质、左侧额叶白质及胼胝体压部ADC值与轻、中度HIE组相比明显降低(P<0.05),而内囊后肢、豆状核、丘脑、小脑及桥脑ADC值在轻、中、重度HIE组间差异均无显著性意义(P>0.05),反映了脑损伤的不均匀性。基底节区ADC值与HIE预后无显著相关性(P>0.05)。结论:DWI在HIE的应用可作为常规MRI的补充。     

高级别胶质瘤假性进展的功能MRI研究

高级别胶质瘤（HGG）治疗后可发生假性进展,但常规MRI对HGG假性进展的诊断价值有限。目前多种功能MRI技术已用于HGG假性进展与真性进展的鉴别诊断,包括扩散成像、¹H-MR波谱成像（MRS）、灌注加权成像（PWI）、酰胺质子转移成像（APT）等,联合这些功能MRI技术及人工智能可进一步改善诊断效能。就这些功能成像及其参数在假性进展方面的研究进展进行综述。     

MRI对头颈部淋巴瘤与鳞癌鉴别研究进展

淋巴瘤的早期确诊对治疗至关重要,而MRI常规扫描对该病的鉴别诊断存在一定的局限性。随着MR新技术的不断发展及新软件的开发,如磁共振波谱（MRS）、灌注加权成像（PWI）及扩散加权成像（DWI）等技术已广泛应用于淋巴瘤的诊断、鉴别诊断及疗效监测。就头颈部淋巴瘤与鳞癌的常规MRI表现及几种功能磁共振成像在其鉴别诊断中的应用予以综述。     

Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques

In recent years, advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic problems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical decision support systems (CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually increased. Hence, the purpose of the current review article is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be introduced into intelligent systems to significantly improve their diagnostic specificity and clinical application.     

Various diffusion magnetic resonance imaging techniques for pancreatic cancer

Pancreatic cancer is one of the most common malignant tumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging (MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging (DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed.     

磁敏感加权成像在新生儿缺氧缺血性脑病中的应用

目的：探讨磁敏感加权成像（SWI）在新生儿缺氧缺血性脑病中的应用价值。方法：对临床拟诊缺氧缺血性脑病（HIE）的105例新生儿行头颅横断面液体衰减反转恢复序列（FLAIR）、快速自旋回波（FSE）、扩散加权图像（DWI）及磁敏感加权成像（SWI）,重点观察SWI对新生儿HIE出血性病灶检出的敏感性。结果：SWI能很好显示HIE伴发的出血灶,尤其是在室管膜生发基质以及脑室内出血的显示率明显高于其他扫描序列。结论：SWI对新生儿HIE伴发的出血,尤其慢性期、微小出血灶以及静脉病变的显示优势明显,而这些信息直接与患儿的预后密切相关,因此它是常规扫描序列的重要补充,有必要将SWI列为HIE的扫描序列。     

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors (SGTs) make up a small portion (approximately 5%) of all head and neck tumors. Most of them are located in the parotid glands, while they are less frequently located in the submandibular glands, minor salivary glands or sublingual gland. The incidence of malignant or benign tumors (BTs) in the salivary glands varies according to the salivary gland from which they originate. While most of those detected in the parotid gland tend to be benign, the incidence of malignancy increases in other glands. The use of magnetic resonance imaging (MRI) in the diagnosis of SGTs is increasing every day. While conventional sequences provide sufficient data on the presence, localization, extent and number of the tumor, they are insufficient for tumor specification. With the widespread use of advanced techniques such as diffusion-weighted imaging, semi-quantitative and quantitative perfusion MRI, studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes. With diffusion MRI, differentiation can be made by utilizing the cellularity and microstructural properties of tumors. For example, SGTs such as high cellular Warthin’s tumor (WT) or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors. Contrast agent uptake and wash-out levels of tumors can be detected with semi-quantitative perfusion MRI. For example, it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out. On quantitative perfusion MRI studies using perfusion parameters such as Ktrans, Kep, and Ve, it is reported that WTs can show higher Kep and lower Ve values than other tumors. In this study, the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.     

Neuroimaging of pediatric posterior fossa tumors including review of the literature

Conventional, anatomical MRI is an essential tool for diagnosis and evaluation of location, quality, and extent of posterior fossa tumors, but offers limited information regarding tumor grade and type. Advanced MRI techniques such as diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) may improve the specific diagnosis of brain tumors in the posterior fossa in children. In this review the conventional neuroimaging findings, as well as the DWI, and DTI characteristics of common pediatric posterior fossa tumors are discussed and summarized.     

磁共振多模态影像技术在短暂性脑缺血发作中的临床应用价值

目的评价动脉磁共振多模态技术在短暂性脑缺血发作(transient ischemic attack,TIA)患者中的应用。方法选取本院2017年7月~2019年3月收治的TIA患者30例,均行常规MRI、弥散加权成像(diffusion weighted imaging,DWI)、磁共振血管成像(MR angiography,MRA)及动脉自旋标记(arterial spin labeling,ASL)技术检查。分析患者常规MRI、DWI及MRA有无异常信号影及脑动脉狭窄、闭塞;对ASL图像进行处理后得到全脑血流量(cerebral blood flow,CBF)图,定性、定量分析ASL-CBF图有无异常灌注;并比较ASL标记延迟时间(post-labeling delay,PLD)=1.5s、PLD=2.5s、MRA对TIA患者脑灌注减低的检出率。结果30例TIA患者的常规MRI及DWI序列均无阳性发现,MRA提示颅内动脉中重度狭窄患者8例(26.7%)。ASL(PLD=1.5s)显示脑灌注减低24例(80.0%),(PLD=2.5s)显示脑灌注减低16例(53.3%)。统计显示(PLD=1.5s)对TIA患者脑灌注减低的检出率高于(PLD=2.5s)检查(χ^2=4.800,P=0.028),ASL(PLD=1.5s、2.5s)对TIA患者脑灌注减低的检出率均高于MRA,差异有统计学意义(χ^2=17.143,P<0.0.001;χ^2=4.444,P=0.035)。结论磁共振多模态技术有助于早期发现TIA患者局部脑组织灌注异常及程度;不同PLD对病灶的检出率及范围有差异,较短PLD能提高检出率,较长PLD能更真实反映血管狭窄较严重TIA患者的脑灌注情况,更好地指导临床治疗。     

功能MRI在肌肉损伤中的应用进展

肌肉损伤的早期确诊有助于临床治疗与预后评估。常规MRI作为评估肌肉损伤的最佳影像方法已广泛应用于临床。而近年发展起来的T2 mapping、扩散加权成像（DWI）及扩散张量成像（DTI）等功能MRI技术能够反映肌肉损伤后病理、生理微观变化,可以无创、定量、客观地评估肌肉损伤的严重程度与再生修复情况,甚至可以早期发现肌肉损伤。就功能MRI在肌肉损伤评估方面的应用进展予以综述。     

Restriction spectrum imaging: An evolving imaging biomarker in prostate MRI

Restriction spectrum imaging (RSI) is a novel diffusion‐weighted MRI technique that uses the mathematically distinct behavior of water diffusion in separable microscopic tissue compartments to highlight key aspects of the tissue microarchitecture with high conspicuity. RSI can be acquired in less than 5 min on modern scanners using a surface coil. Multiple field gradients and high b‐values in combination with postprocessing techniques allow the simultaneous resolution of length‐scale and geometric information, as well as compartmental and nuclear volume fraction filtering. RSI also uses a distortion correction technique and can thus be fused to high resolution T2‐weighted images for detailed localization, which improves delineation of disease extension into critical anatomic structures. In this review, we discuss the acquisition, postprocessing, and interpretation of RSI for prostate MRI. We also summarize existing data demonstrating the applicability of RSI for prostate cancer detection, in vivo characterization, localization, and targeting. Level of Evidence: 5 J. Magn. Reson. Imaging 2017;45:323–336.     

脑缺血再灌注大鼠模型FAIR-PWI研究

目的:探讨流动敏感交替反转恢复序列灌注成像(FAIR- PWI)对大鼠脑缺血后再灌注的评价.方法:使用GE 3.0T MRI成像仪,在完成T1WI、T2WI、弥散加权成像(DWI)和FAIR - PWI序列后,对SD大鼠行暂时性右侧大脑中动脉闭塞(TMCAO)手术,分别在脑缺血3h和再灌注3h及21h行重复上述MRI检查;最后进行病理学TTC染色观察梗死区域及范围.结果:TMCAO后3h时,患侧大脑半球DWI信号升高、FAIR - PWI灌注增加、且皮质相对脑血流量(rCBF)大于基底节区;再灌注3h及21h后,患侧大脑半球DWI信号面积(0.63±0.1.2cm2、0.48±0.23cm2)仍高于FAIR - PWI高灌注面积(0.51±0.26cm2、0.34±0.44cm2,P=0.01),皮质及基底节区rCBF较缺血时增加.TTC染色示梗死面积(0.42±0.78cm2)小于DWI异常信号面积,而大于FAIR - PWI高灌注面积,且梗死区以基底节为主.结论: FAIR- PWI结合DWI能对早期缺血再灌注进行动态观察及半定量测量,可能为临床溶栓治疗方案的预后判断和随访提供重要参考.