磁共振扩散加权成像在胰腺癌诊断中的价值

目的探讨磁共振扩散加权成像在胰腺癌诊断中的价值。方法选择2012年1月～2013年1月间临床可疑胰腺癌患者75例,对这些患者进行磁共振扩散加权成像检查,将检查结果与病理结果比较,明确两者之间的相关性,同时确定磁共振扩散加权成像在胰腺癌诊断中的敏感性、特异性。结果75例可疑胰腺癌患者经DWI检查,诊断为胰腺癌38例,与病理结果比较,两者存在相关性（r=23．12,P=-0．00〈0．05）,且相关系数为0．56。同时与病理结果比较DWI诊断胰腺癌的敏感性为73．33％,特异性为83．33％,阳性预测值和阴性预测值分别为86．84％和67．57％。结论磁共振扩散加权成像作为无创检查手段能够准确地对胰腺占位做出定性诊断,在临床应用价值较大。     

磁共振扩散成像及磁敏感加权成像在脊髓损伤中的应用

目前,脊髓MR成像常规检查是诊断脊髓损伤的最佳手段,能清楚地显示受损伤脊髓形态及信号改变,以此明确疾病,但是当MRI常规检查出现信号改变时往往提示脊髓损伤严重,并非病变的早期,使得病人错过最佳治疗时期。而MR扩散加权成像(DWI)和磁敏感加权成像(SWI)对脊髓损伤的早期诊断、治疗和预后均具有重要价值。对DWI及SWI在急慢性脊髓损伤中的应用情况及研究进展进行综述。     

MR扩散成像在精神神经性狼疮的研究进展

系统性红斑狼疮（SLE）累及神经系统而出现各种神经精神症状时称为精神神经性狼疮（NPSLE）,NPSLE是SLE的主要死亡原因之一。早期诊断并治疗NPSLE对病人的预后有重要的意义。扩散张量成像及扩散峰度成像能够实现对早期NPSLE脑部损伤的可视化,其特征参数的变化能够反映NPSLE的病理过程,具有一定的判断病情活跃性和预后的价值。就扩散张量成像及扩散峰度成像对NPSLE的相关研究及进展进行综述。     

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.     

肾脏MR扩散峰度成像研究进展

MR扩散峰度成像（DKI）基于多项式模型,能够量化组织中水分子的扩散运动与自由高斯运动的偏差。DKI技术可以定量评价组织微环境的复杂性和异质性,近年来已用于评价肾脏功能及相关疾病,在肾脏肿瘤的分级,以及在梗阻性肾病、糖尿病肾病、高尿酸血症肾病等常见疾病的早期诊断中具有一定的应用价值。就DKI成像原理及在正常肾脏和肾脏常见疾病中的研究进展予以综述。     

Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.     

A fast schema for parameter estimation in diffusion kurtosis imaging

Diffusion kurtosis imaging (DKI) is a new model in magnetic resonance imaging (MRI) characterizing restricted diffusion of water molecules in living tissues. We propose a method for fast estimation of the DKI parameters. These parameters – apparent diffusion coefficient (ADC) and apparent kurtosis coefficient (AKC) – are evaluated using an alternative iteration schema (AIS). This schema first roughly estimates a pair of ADC and AKC values from a subset of the DKI data acquired at 3 b-values. It then iteratively and alternately updates the ADC and AKC until they are converged. This approach employs the technique of linear least square fitting to minimize estimation error in each iteration. In addition to the common physical and biological constrains that set the upper and lower boundaries of the ADC and AKC values, we use a smoothing procedure to ensure that estimation is robust. Quantitative comparisons between our AIS methods and the conventional methods of unconstrained nonlinear least square (UNLS) using both synthetic and real data showed that our unconstrained AIS method can significantly accelerate the estimation procedure without compromising its accuracy, with the computational time for a DKI dataset successfully reduced to only 1 or 2 min. Moreover, the incorporation of the smoothing procedure using one of our AIS methods can significantly enhance the contrast of AKC maps and greatly improve the visibility of details in fine structures.     

全身DWI的正常表现及在转移瘤筛查中的临床应用

目的:探讨磁共振全身扩散加权成像(全身DWI)的正常表现及在转移瘤筛查中的应用价值。方法:20例健康志愿者及25例疑似或确诊恶性肿瘤患者行磁共振全身扩散加权成像,其中11例肿瘤患者同时行PET/CT检查。全身DWI应用STIR抑制背景信号,从头顶至股骨上分段无间隔扫描,共覆盖1080～1440mm,b值取0及600s/mm2。结果:在健康志愿者的全身DWI像上,脑实质、涎腺、椎间盘、脊髓、脾脏、肾脏和前列腺、睾丸、子宫、卵巢等脏器呈高信号,其余脏器及骨骼呈等信号。原发恶性肿瘤及转移灶在全身DWI呈明显高信号,对比度高于常规MRI序列。25例患者全身DWI共检出70处高信号病灶,包括原发恶性肿瘤及转移灶68处,良性病灶2处,显示率为98.6%。11例PET/CT检查共有20处阳性显像,原发恶性肿瘤及转移灶16处,良性病灶4处,显示率100%。结论:磁共振全身扩散加权成像一次检查可完成从头顶至股骨上段的大范围成像,对恶性肿瘤原发灶及转移灶有较高的显示率,可以作为恶性肿瘤患者原发及转移灶筛查的有力工具之一。     

扩散峰度成像在直肠癌中的研究进展

扩散峰度成像（DKI）是一种以生物组织内水分子扩散运动呈非高斯分布为理论基础的功能MRI技术,能够描述组织内水分子扩散运动受限的真实情况,准确反映组织微观结构的复杂程度,目前已用于直肠癌的诊疗及疗效评估。介绍DKI的原理及其定量参数,概述DKI在直肠癌诊断、临床病理特征评价、分子生物学特征表征及新辅助疗效评估方面的研究进展,分析DKI在直肠癌应用中的局限性。     

Diffusion-weighted imaging of pancreatic cancer

Magnetic resonance imaging (MRI) is a reliable and accurate imaging method for the evaluation of patients with pancreatic ductal adenocarcinoma (PDAC). Diffusion-weighted imaging (DWI) is a relatively recent technological improvement that expanded MRI capabilities, having brought functional aspects into conventional morphologic MRI evaluation. DWI can depict the random diffusion of water molecules within tissues (the so-called Brownian motions). Modifications of water diffusion induced by different factors acting on the extracellular and intracellular spaces, as increased cell density, edema, fibrosis, or altered functionality of cell membranes, can be detected using this MR sequence. The intravoxel incoherent motion (IVIM) model is an advanced DWI technique that consent a separate quantitative evaluation of all the microscopic random motions that contribute to DWI, which are essentially represented by molecular diffusion and blood microcirculation (perfusion). Technological improvements have made possible the routine use of DWI during abdominal MRI study. Several authors have reported that the addition of DWI sequence can be of value for the evaluation of patients with PDAC, especially improving the staging; nevertheless, it is still unclear whether and how DWI could be helpful for identification, characterization, prognostic stratification and follow-up during treatment. The aim of this paper is to review up-to-date literature data regarding the applications of DWI and IVIM to PDACs.     

磁共振扩散加权成像在直肠肿瘤性病变诊断中的价值

目的：通过对不同类型直肠肿瘤病例DWI图像分析和ADC值的测量探讨扩散加权成像对直肠肿瘤性病变的诊断价值。方法比较8例直肠腺瘤,30例中分化腺癌,6例低分化腺癌,7例黏液腺癌,6例淋巴瘤及5例间质瘤的ADC值的差异。结果①直肠淋巴瘤的ADC值明显低于直肠癌、直肠腺瘤,差异有统计学意义（ P＜0．05）,淋巴瘤与间质瘤之间差异无统计学意义（ P ＞0．05）;②直肠腺瘤ADC值低于粘液腺癌（ P ＜0．05）,与间质瘤、腺癌之间差异无统计学意义（ P＞0．05）;③间质瘤 ADC值低于粘液腺癌（ P ＜0．05）,与淋巴瘤、腺癌、腺瘤之间差异无统计学意义（ P ＞0.05）;④粘液腺癌ADC值高于中分化腺癌（ P ＜0．05）,与低分化腺癌之间差异无统计学意义（ P ＞0．05）,中分化、低分化腺癌之间差异无统计学意义（ P ＞0．05）。结论扩散加权成像对不同类型直肠肿瘤、不同类别的直肠腺癌具有一定的鉴别诊断价值,联合MR常规扫描可提高诊断效能。     

急性一氧化碳中毒后迟发性脑病的MRI研究进展

急性CO中毒后迟发性脑病（DEACMP）是急性CO中毒后最严重的并发症之一,其发病机制迄今不明。MRI能较好的显示DEACMP的脑组织的病理改变有重要的临床应用价值,而功能MR成像技术为该疾病开辟了新的研究方向。本文主要对MRI及功能MR技术在DECAMP中的研究近况予以综述。     

磁共振扩散加权成像早期预测肺癌化疗疗效的价值

目的：评价磁共振扩散加权成像（DWI）对肺癌化疗疗效的早期预测价值。方法：对30例经病理证实的肺癌患者,在化疗前及第一周期化疗后进行MRI检查,包括常规T1wI,T2 wI及DWI检查。根据第二周期化疗后肿瘤最大径退缩率,按RECIST标准将患者分为治疗有效组和无效组,比较两组中肿瘤的表观扩散系数（ADC值）和最大径的差异,分析ADC值变化率的受试者工作特征曲线（ROc）,获得预测治疗有效的ADC值变化率临界值（cut—offvalue）。结果：第一周期化疗后,有效组化疗前后病灶的平均ADC值的差异有统计学意义（P值d0．001）;有效组和无效组中肿瘤ADC值的差异有统计学意义（P-0．031）;肿瘤最大径在两组间的差异无统计学意义（P-0．210）。以ADC值升高8．5％作为ADC值变化率诊断分界点,预测治疗获得PR的敏感度为85．7％,特异度为72．9％。结论：ADC值可以对肺癌化疗疗效进行早期监测。     

扩散峰度成像与扩散加权成像在诊断宫颈鳞癌分级中的价值

目的对比分析扩散峰度成像(DKI)与扩散加权成像(DWI)诊断宫颈鳞癌分级的价值。方法回顾性纳入经术后病理证实的宫颈鳞癌病人42例,年龄39~69岁,平均(54.9±7.9)岁。以病理结果为金标准,分为高中分化组(27例)和低分化组(15例),分别测量2组肿瘤实质区平均扩散峰度(MK)值、平均扩散系数(MD)值及平均表观扩散系数(ADC)值、最小ADC值,采用独立样本t检验比较2组间各参数值的差异,采用受试者操作特征(ROC)曲线评价各参数值的诊断效能及最佳诊断阈值,并根据约登指数确定各参数相应的敏感度和特异度。结果2名观察者测得各参数的一致性均良好(均ICC>0.60,P<0.05)。低分化组的MK值高于高中分化组,而MD、平均ADC、最小ADC值均低于高中分化组(均P<0.05)。采用单一参数鉴别低分化与高中分化宫颈鳞癌时,MK为0.88时,AUC最大(0.877)、敏感度(92.6%)最高;MD为1.04×10^-3mm^2/s时,特异度(86.7%)最高。联合MK、MD和最小ADC值诊断时,AUC最大(0.937),敏感度最高(96.3%)。结论与传统DWI相比,DKI可更有效地鉴别低分化与高中分化宫颈鳞癌,联合应用DKI和DWI参数可有效提高诊断效能。     

磁共振扩散加权成像在宫颈癌诊断中的应用

目的评价MR弥散加权成像(DWI)在宫颈癌诊断中应用的价值。方法对30例非宫颈肿瘤女性的子宫颈和50例宫颈癌患者的子宫颈进行常规MRI扫描和横断面DWI(b=600s/mm2),比较正常宫颈和宫颈癌病灶的表观弥散系数(apparent diffusion coefficient,ADC)值。结果正常子宫颈DWI表现为粘液,内、中、外带四层结构,其平均ADC值〔(1.71±0.14)×10-3 mm2/s)〕显著高于宫颈癌的ADC值〔(0.97±0.13)×10-3 mm2/s)〕(P<0.01)。结论 ADC值可有效地定量区分宫颈癌与正常宫颈,DWI更容易显示宫颈癌及其周围侵犯和盆腔淋巴结转移。     

扩散成像技术在臂丛神经病变的应用研究进展

扩散成像技术是利用组织的扩散特性成像的新型MRI检查技术,初期主要应用于中枢神经系统疾病的诊断,而后逐渐被应用于脊髓、坐骨神经、正中神经等。臂丛神经是人体最复杂的周围神经,支配上肢的感觉与运动功能。臂丛神经病变常见、多发。针对扩散成像技术原理、扩散成像在臂丛神经成像中的优势与限制及臂丛神经病变中的扩散成像技术应用研究作一综述,以提高扩散成像对臂丛神经病变诊断的应用价值。     

Magnetic resonance diffusion tensor imaging of the testis: Preliminary observations

IntroductionTo evaluate the feasibility of testis diffusion tensor imaging (DTI), to determine normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values and to assess the efficacy of DTI in characterizing testicular pathology.Materials and methodsFifty-six men underwent MRI of the scrotum, including DTI. Parametric and non-parametric statistical tests were used to compare the ADC and FA between the cranial, middle and lower thirds of normal testis and between the bilateral testicular thirds. Comparison between the ADC and FA of normal testis, malignant and benign testicular lesions was performed.ResultsNo significant differences of the ADC and FA in normal testis between the cranial, middle and lower thirds and between the bilateral testicular thirds were found. ADC was significantly lower in malignancies compared to normal testis (P = 0.006) and benign testicular lesions (P = 0.006). FA was significantly higher both in malignancies (P = 0.001) and benign lesions (P < 0.001) compared to normal testis. FA in malignancies did not differ from FA in benign lesions (P = 0.221)ConclusionsThis study shows the feasibility of testis DTI. Both ADC and FA significantly differ between testicular lesions and normal testis, although FA did not show an incremental diagnostic value compared to ADC in lesion differentiation.     

MR扩散加权成像在宫颈癌诊断和分期中的应用价值

目的 探讨磁共振扩散加权成像（DWI）在宫颈癌诊断的敏感性、分期的准确性及盆腔淋巴结转移的检出率和定性准确率中的应用价值.方法 回顾性分析经术后病理证实的98例宫颈癌患者的影像资料,比较DWI联合常规MRI序列与单纯常规MRI序列在宫颈癌诊断、分期及盆腔淋巴结转移方面的差异.结果 DWI联合常规MRI序列对Ⅰb期的漏诊率（1/20）低于单纯常规MRI序列漏诊率（5/20）.DWI联合常规MRI序列对Ⅱb期分期准确率（21/23）高于单纯常规MRI序列准确率（14/23）;其余各期分期,两者无明显差异.DWI联合常规MRI序列对盆腔淋巴结转移的检出率（135/148）和定性准确率（76/82）均高于单纯常规MRI序列的检出率（101/148）和定性准确率（56/82）.结论 相对于常规MRI序列,DWI联合常规MRI序列对宫颈癌的诊断更敏感,Ⅱb期分期更准确,盆腔淋巴结检出率和定性准确率更可靠.     

Application of magnetic resonance imaging in cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction and is caused by static or dynamic repeated compression of the spinal cord resulting from degenerative arthritis of the cervical spine and some biological injuries to the cervical spine. The T2 signal change on conventional magnetic resonance imaging (MRI) is most commonly associated with neurological deficits. Diffusion tensor imaging and MR spectroscopy show altered microstructure and biochemistry that reflect patient-specific pathogenesis and can be used to predict neurological outcome and response to intervention. Functional MRI can help to assess the neurological functional recovery after decompression surgery for CSM.     

腰椎间盘退行性变的MR扩散张量成像初步研究

目的 运用DTI初步探讨无创评价活体椎间盘纤维环退变.方法 选择2010年9月至2011年3月腰椎门诊就诊行腰椎MR检查患者,排除脊柱畸形、肿瘤及相关手术患者,共纳入研究对象88例,年龄16 ～63岁,平均(37±13)岁.对研究对象进行快速自旋回波及平面回波成像.剔除磁敏感重的图像,共获得428个椎间盘,测量其平均扩散系数(MD)、各向异性分数(FA)并获得其纤维环成像图,根据纤维环示踪图(FT)图形态学改变,对纤维环进行分型并测量其MD和FA,并进行比较.数据资料为非正态分布,以四分位间距及中位数表示.采用SPSS11.0软件包,x2检验进行统计学分析.结果 运用纤维环示踪技术每个椎间盘均可得到纤维环成像图,且不同Pfirrmann级别其纤维环类型不同,纤维环分型与Pfirrmann分级密切相关:规则型FT图135个,其中PfirrmannⅡ级(92个)比例最高,占68.15％;杂乱型纤维环FT图195个,以PfirrmannⅢ(93个)、Ⅳ级(30个)为主,占63.07％;团块型纤维环FT因98个,以PfirrmannⅣ(39个)、Ⅴ级(43个)为主,占83.68％,差异具有统计学意义(Mantel-Haenszel x2检验,x2=183.90,P＜0.01).完整型FA值为0.32(0.29 ～0.35),MD值为12.40(11.50 ～13.20)×10-10 mm2/s;杂乱型FA值为0.35(0.33 ～0.38),MD值为11.10(9.92 ～ 12.00)×10 10mm2/s;团块型FA值为0.54(0.46～0.62),MD值为6.30(5.03～7.72)×10-10mm2/s.纤维环结构越杂乱,其MD值越低,FA值越高,差异具有统计学意义(Kruskal-Wallis秩和检验,x2值分别为219.74、243.88,P值均＜0.01).结论 DTI可无创性评估活体椎间盘结构变化,MD值及FA值有助于评价椎间盘退变程度.