3.0T磁共振扩散加权成像在肝硬化与肝癌的应用研究

目的 探讨3.0T磁共振扩散加权成像(DWI)对肝硬化与肝癌的诊断价值.方法 对10例健康志愿者、21例肝硬化患者及30例肝癌患者于3.0T磁共振成像系统行磁共振扩散加权成像检查,分析正常肝脏、肝硬化与肝癌扩散加权成像的特点,并测量正常肝脏、肝硬化与肝癌的ADC值,分析三者ADC值范围及不同b值时,ADC值对正常肝脏、肝硬化及肝癌的诊断灵敏度与特异性.结果 当b值为100 s/mm2时,正常肝脏ADC值分别与肝硬化、肝癌存在显著差异(P＜0.05),但肝硬化与肝癌ADC值之间无差异(P＞0.05);当b值分别为300 s/mm2和1000 s/mm2时,正常肝脏、肝硬化及肝癌的ADC值有显著性差异(P＜0.01).当b值为300 s/mm2时,ADC值对肝硬化的诊断灵敏度及特异性分别为82.6%和100%;对肝细胞癌的诊断灵敏度及特异性分别为95.2%和90.4%.当b值为1000 s/mm2时,ADC值对肝硬化的诊断灵敏度及特异性分别为86.9%和100%;对肝细胞癌的诊断灵敏度及特异性分别为95.2%和66.7%.结论 在3.0T磁共振成像系统进行肝脏DWI,通过综合及量化分析肝硬化与肝癌ADC值的变化规律,能为肝硬化及肝癌的诊断提供更有力的依据.     

肝纤维化和肝硬化的MR扩散成像及与病理对照、CT灌注参数的相关性研究

目的利用扩散加权成像(DWI)检查技术测定肝纤维化和肝硬化患者表观扩散系数(ADC)值并与正常对照组及相应病理对照来反映肝纤维化程度,同时分析其与血流动力学指标的相关性。资料与方法分别对44例肝纤维化患者、49例肝硬化患者及46名正常对照者利用DWI(b=500s/mm2)技术进行ADC值测定,并与病理改变及CT灌注参数作对照研究。结果肝纤维化组、肝硬化组ADC值降低;对照组、S2、S3组ADC值逐渐降低;Child-PughA、B、C分级组中ADC值无差别;肝纤维化不同分级与Child-PughA、B、C分级组中S3组ADC值降低而ChildC组ADC升高;对照组及肝纤维化组ADC值均与CT灌注参数间无相关性;肝硬化组ADC值与CT灌注参数(BV、BF)正相关。结论b值为500s/mm2时可显示肝纤维化及肝硬化患者ADC值降低,肝硬化患者ADC值较肝纤维化患者ADC值升高与肝血流量增加有关。     

胆碱酯酶、前白蛋白和腺苷脱氨酶在肝胆疾病诊断中的意义

血液中的胆碱酯酶（ChE）由肝细胞生成,在肝细胞合成酶功能受损的急慢性肝炎、肝硬化、低蛋白血症等疾病中活力下降,从而反映肝脏机能。血液前白蛋白（PA）浓度在急性炎症、恶性肿瘤或肝硬化时下降,对了解肝功能不全具有敏感性。腺苷脱氨酶（ADA）是一种与机体细胞免疫活性相关的核酸代谢酶,血液中ADA及其同工酶水平对肝胆疾病的诊断、鉴别诊断、治疗及免疫功能有重要意义。     

磁共振成像T1值、T2值和ADC值与肝脏纤维化模型病理评分分级纤维化分期诊断结果相关性研究

目的：探讨磁共振成像T1值、T2值、ADC值对肝脏纤维化病理评分分级纤维化分期诊断的价值和意义。方法：将大白兔分为正常对照组（4只）和肝脏纤维化模型组（13只）,分别对其进行常规MR扫描,测量肝脏组织T1值和T2值;磁共振弥散加权成像扫描（MR-DWI）,测量肝脏组织表观扩散系数（ADC值）。取肝脏组织标本做常规HE染色和网状纤维染色（Gomoris法）,以病理组织学评分分级和纤维化分期诊断结果为标准,研究分析T1值、T2值和ADC值在肝脏纤维化不同评分分级和纤维化分期间的变化情况;采用统计学相关分析法研究T1值、T2值和ADC值在与病理积分、评分分级和纤维化分期诊断结果之问的相关性。统计学分析采用SPSS13．0,单相分析法,P〈0．05为差异有统计学意义。结果：磁共振成像T1值、T2值、ADC值测量结果在对照组和不同评分分级和纤维化分期间的差异性具有显著的统计学意义（P〈0．05）;在肝脏纤维化模型组中T1值和T2值明显高于对照组,且随着评分分级和纤维化分期的增加而逐渐增加;肝脏纤维化模型组中ADC值明显低于对照组,随着评分分级和纤维化分期的增加降低越显著。相关分析结果表明T2值与病理积分、评分分级和纤维化分期诊断结果之间呈显著正相关性（P〈0．01）;ADC值与病理积分、评分分级和纤维化分期诊断结果之间表现显著负相关性（P〈0．01）。结论：在肝脏发生纤维化时,定量检测磁共振成像中的T1值、T2值和ADC值,能够评估肝脏纤维化病理评分分级和纤维化分期,作为非损伤性检查方法的磁共振成像可以用于临床肝脏纤维化定量诊断。     

定量研究表观扩散系数与T2值在肝局灶性小病变中的应用价值

目的通过对表观扩散系数（ADC）与T2值的定量对比研究,探讨ADC值与T2值在肝脏局灶性小病变定性诊断中的价值. 资料与方法对临床发现有肝脏局灶性小病变患者73例（其中包括原发性肝细胞癌22例22个病灶,肝转移瘤16例26个病灶,肝海绵状血管瘤27例38个病灶,肝囊肿8例11个病灶）分别行磁共振扩散加权成像（DWI）和常规快速自旋回波（FSE）T2WI,然后测量计算各病变的ADC值及T2值,进行统计学分析,对比两种量化方法（ADC值和T2值）对肝脏良恶性病变的诊断准确性. 结果肝脏恶性病变的ADC值明显低于良性病变（P＜0.01）,其诊断准确性为93.8%;肝脏恶性病变的T2值也低于良性病变（P＜0.05）,但两者数值重叠较多,其诊断准确性为77.3%,有明显统计学差异（P＜0.05）. 结论利用ADC值在定性方面优于T2值,对肝脏局灶性小病变的诊断更具临床价值.     

肝脏ADC图辅助常规腹部MRI用于胆汁淤积病人肝纤维化和临床肝硬化程度的评估

<正>摘要目的肝脏表观扩散系数(ADC)值和ADC相关指标与原发性胆汁性肝硬化梅奥风险评分(MRSPBC)和肝脏标本的METAVIR评分联合确定扩散加权MRI(DWMRI)的临     

多b值弥散加权成像对乙肝肝硬化分级的诊断价值探讨

目的探讨乙肝肝硬化患者不同肝叶磁共振弥散加权成像不同b值对肝硬化Child-Pugh分级的诊断价值。方法收集72例乙肝肝硬化患者和23例健康志愿者,其中肝硬化患者按Child-Pugh评分系统分为A、B、C三组分别为22例、26例和24例,均行肝脏MR-DWI扫描,设定不同的弥散敏感系数(b值)分别为0s/mm2、400s/mm2、600s/mm2、800s/mm2,测定每个受试者不同b值下肝脏各叶的ADC值。分别统计各b值肝左外叶、肝左内叶、肝右叶和肝尾状叶的ADC值,分析不同肝叶ADC值与Child-Pugh分级的相关性,使用ROC曲线评估肝叶ADC值对肝硬化分级的诊断效能。结果在不同b值下,肝硬化组肝脏ADC值均低于正常对照组,且各肝叶ADC值与肝硬化Child-Pugh分级均呈负相关(P0.05)。结论 DWI可以对乙肝肝硬化进行定量检查,有助于临床早期无创伤性评估肝硬化分级。     

脾脏ADC值与门脉高压及脾亢关系的初步探讨

目的 探究脾脏表观扩散系数(ADC)值与门脉高压的关系.方法 52例行腹部MRI(包括扩散加权成像)检查,其中正常组18例,肝硬化无门脉高压症组24例及有门脉高压症组10例,分别测量脾脏ADC值,并进行组间比较.分析肝硬化患者脾亢指标--外周血细胞(RBC/WBC/PLT)数值与脾脏ADC值的相应关系.结果 随着门脉高压的出现脾脏ADC值降低,2组间的差异有统计学意义(P<0.05).ADC值的变化与脾亢指标无明显相关性.结论 门脉高压时脾脏ADC值的下降反映了相应的血流动力学状况,但并不能反映相伴发生的脾亢.     

肝脏扩散加权成像方法研究

目的探讨肝脏扩散加权成像(DWI)的方法。资料与方法将头部DWI序列的参数修正后用于肝脏成像,并以此序列对机器校准纯水水模对32名正常人行b值为0~1000s/mm2的DWI,测量纯水的表观扩散系数(ADC)值与正常人肝脏信号强度的ADC值。结果纯水ADC值约为2.30×10-3mm2/s。对于正常人,随b值增大肝脏信号强度与ADC值降低,存在负相关性(信号强度与ADC值的相关性分别为r=-0.903,P=0.00;r=-0.795,P=0.00);b值为50~250s/mm2时得到的ADC值与变异程度均偏大;b值为300~1000s/mm2,ADC值变得稳定,变异性减小;但b值为1000s/mm2时,肝脏信号强度减低,解剖结构显示不清。结论本研究所用的肝脏DWI方法能准确反映水分子的扩散状态,用b值300~800s/mm2范围,能得到清晰的DWI图像与稳定的ADC值。     

兔VX2肝移植瘤TACE治疗前后ADC值与细胞密度的相关性研究

目的：探讨兔VX2肝移植瘤模型TACE治疗前后磁共振扩散加权成像的ADC值与细胞密度的相关性研究。方法：建立兔VX2肝移植瘤动物模型,并随机分为对照组（n=10）和TACE组（n=10）。接种后用二维超声监测肿瘤生长至1～2cm大小,对照组经肝动脉插管给予生理盐水10ml;TACE组给予超液化碘油2mg/kg和阿霉素2mg／kg。介入术前和术后第7天（处死动物前）行DWI检查,观察介入治疗前后肿瘤的磁共振信号及表观扩散系数（ADC值）变化情况。据常规HE染色计算细胞密度,分析肿瘤治疗前后的ADC值和细胞密度的变化及其相关性。结果：对照组不同b值所对应正常肝组织的ADC值明显高于肿瘤组织的ADC值（P〈0．05）,对照组在注人生理盐水前后的ADC值差别无统计学意义（P〉0．05）,肿瘤组织的ADC值与细胞密度呈负相关关系（P〈0．05）。TACE组介入治疗前ADC值高于治疗后的ADC值,差别有统计学意义（P〈0．05）,肿瘤TACE术后ADC值与细胞密度存在负相关性（P〈0．05）,且介入术后TACE组肿瘤细胞密度较对照组降低（P〈0．05）。结论：肿瘤组织与正常肝脏ADC值存在显著差异,ADC值能反映出肿瘤治疗前后组织微观结构的改变,可用于评估肿瘤增殖情况及治疗疗效。     

DSA功能性参数的提取与利用

本文介绍了在临床实际中利用功能性参数，对冠状动脉ＤＳＡ心肌血流灌注成像、冠状动脉血流量测定、左心室功能测定、肺动脉高压程度的评价等项目研究结果。重点讨论了提取ＤＳＡ功能性参数的一般方法，认为功能性参数在现代影像诊断学中的作用是对疾病做出程度、定量、动态及功能诊断。     

Current Status of Optical Imaging for Evaluating Lymph Nodes and Lymphatic System

Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.     

Fast imaging of phosphocreatine in the normal human myocardium using a three-dimensional RARE pulse sequence at 4 Tesla

PURPOSE: To investigate the use of a three-dimensional rapid acquisition with relaxation enhancement (RARE) pulse sequence for direct acquisition of phosphocreatine (PCr) images of the human myocardium. MATERIALS AND METHODS: A short elliptical birdcage radiofrequency (RF) body coil was constructed to produce a uniform flip angle throughout the chest cavity. In vivo images using a spectrally-selective RARE sequence with a spatial resolution of 1.2 cm x 1.2 cm x 2.5 cm (4 cm(3)) were acquired in nine minutes and 40 seconds. RESULTS: Scans of phantoms demonstrated excellent spectral selectivity. The signal-to-noise ratio in the myocardium ranged from 12.6 in the anterior wall to 5.3 in the mid septum. CONCLUSION: This study demonstrates that PCr data can be acquired using a three-dimensional RARE sequence with greater spatial and temporal resolution than spectroscopic techniques.     

Molecular imaging programs in the United States: results of a national survey

RATIONALE AND OBJECTIVES: We sought to identify and describe the characteristics of molecular imaging (MI) programs in the United States and to determine the factors considered critical for their future. MATERIALS AND METHODS: In a cross-sectional study, a validated survey was sent to members of the Society of Chairmen in Academic Radiology Departments (SCARD) in the United States, and 26 variables were studied. RESULTS: The response rate was 40.3%; 67.9% of the departments surveyed have an MI program. The main focus of 47.4% of departments is oncology. The number of radiologists working for the department was the only variable found to be significantly positively correlated with (1) number of researchers in the MI program, (2) number of MI modalities available, (3) total number of grants, and (4) having ongoing MI clinical trials. These four variables plus the number of federal grants and the space used by MI programs were independent of the geographical region, hospital size (number of beds), and department size (number of radiological examinations per year). All the MI programs received grants during 2005. Only 16.1% have no alliances with industry. Among all the departments, 82% identified staff training and recruitment as the keys for success; 78.57% considered oncology the most important future application of MI and cancer management the hospital service most affected by MI. CONCLUSION: MI programs are starting to be more widespread throughout the United States, and the trend is for more academic radiology departments to become engaged in MI activities; their development is independent of department characteristics. Radiology departments strongly agreed about the key components for success of MI initiatives and the areas that will be most affected by MI applications.     

Molecular imaging of the lungs

An emerging suite of new imaging techniques offer the ability to monitor and quantify molecular and cellular processes in the lungs noninvasively. These techniques take advantage of dramatic advances in both imaging technology as well as molecular and cell biology. Molecular imaging is being used with increasing regularity in research protocols, and forms of molecular imaging have found their way into the patient care setting (eg, positron emission tomography imaging in cancer). Such techniques will afford the basic scientist as well as the clinician an unprecedented opportunity for in vivo study of the lung biology that drives normal pulmonary physiology as well as pathophysiology.     

Dynamic bioluminescence imaging for quantitative tumour burden assessment using IV or IP administration of <Emphasis Type="SmallCaps">d</Emphasis>-luciferin: effect on intensity,time kinetics and repeatability of photon emission

Introduction In vivo bioluminescence imaging (BLI) is a promising technique for non-invasive tumour imaging. d-luciferin can be administrated intraperitonealy or intravenously. This will influence its availability and, therefore, the bioluminescent signal. The aim of this study is to compare the repeatability of BLI measurement after IV versus IP administration of d-luciferin and assess the correlation between photon emission and histological cell count both in vitro and in vivo. Materials and methods Fluc-positive R1M cells were subcutaneously inoculated in nu/nu mice. Dynamic BLI was performed after IV or IP administration of d-luciferin. Maximal photon emission (PE_max) was calculated. For repeatability assessment, every acquisition was repeated after 4 h and analysed using Bland–Altman method. A second group of animals was serially imaged, alternating IV and IP administration up to 21 days. When mice were killed, PE_max after IV administration was correlated with histological cell number. Results The coefficients of repeatability were 80.2% (IV) versus 95.0% (IP). Time-to-peak is shorter, and its variance lower for IV (p < 0.0001). PE_max was 5.6 times higher for IV. A trend was observed towards lower photon emission per cell in larger tumours. Conclusion IV administration offers better repeatability and better sensitivity when compared to IP. In larger tumours, multiple factors may contribute to underestimation of tumour burden. It might, therefore, be beneficial to test novel therapeutics on small tumours to enable an accurate evaluation of tumour burden. Marleen Keyaerts is a Ph. D. fellow of the Research Foundation—Flanders (Belgium; FWO).     

Phase insensitive preparation of single-shot RARE: Application to diffusion imaging in humans

Although RARE and GRASE can produce single-shot images of excellent quality, their utility has been restricted because preparation of the magnetization with interesting contrast before imaging can cause severe artifacts. These artifacts relate to the strong sensitivity of multiple spin echo sequences to the phase of the prepared magnetization. Modifications of the RARE sequence to eliminate these artifacts are discussed, and an approach that eliminates the artifact producing signals from the very first echo is presented. The approach is applied to diffusion imaging of the human brain in normal volunteers and one patient.     

Head and neck imaging: the role of CT and MRI

High-resolution computed tomography (CT) and magnetic resonance imaging (MRI) have become indispensable tools for the evaluation of conditions involving the head and neck. Complex anatomic structures and regions, such as the orbit, skull base, paranasal sinuses, deep spaces of the neck, larynx, and lymph nodes, require that the radiologist be familiar with the imaging modalities available and their appropriate applications. The purpose of this article is to review the techniques of CT and MRI and the roles they play in clinical practice, including head and neck disorders.     

MR灌注成像在评价脑内胶质瘤残留或复发方面的价值

目的 用受试者操作特性（ROC）分析方法评价常规MR和灌注成像（PWI）对脑内胶质瘤术后早期残存与复发的诊断价值。资料与方法 回顾性分析经手术与病理证实的脑内胶质瘤86例,其中术后残留或复发50例,均经二次手术证实;其余36例术后随诊18个月以上无复发表现。所有患者均行常规MR／和PWI,获得相对脑血流容积彩图,并计算肿瘤相对血容积比值。采用Windows98版ROCKIT软件进行ROC分析,使用微软Excel2000软件绘制ROC曲线图。结果 86例胶质瘤术后的影像资料经ROC分析显示,常规MR曲线的a值（截距）为0．12,b值（斜率）为0．95,Az为0．5343;结合PWI的方法a值为0．56,b值为1．23,Az为0．6370。两种方法ROC曲线的Az差异有统计学意义（P=0．0001,〈0．01）。在胶质瘤术后残存或复发的诊断方面,结合PWI的MRI诊断方法明显优于常规MRI。结论 在术后早期,对胶质瘤残存与复发的监测方面,常规MR／结合PWI能明显提高特异性和敏感性。     

磁共振扩散张量成像在星形细胞瘤分级中的价值

目的 探讨磁共振扩散张量成像（DTI）技术在星形细胞瘤分级中的应用价值。资料与方法对15例1-2级星形细胞瘤及22例3～4级星形细胞瘤进行了MR检查，扫描序列包括T1WI、T2WI、液体衰减反转恢复序列（FLAIR）、DTI及增强后T1WI。结果脑部分各向异性指数（FA）图、FA彩色编码图、纤维束追踪图均能显示脑白质纤维受累情况，而常规MRI难以显示。1—2级星形细胞瘤组肿瘤区表观扩散系数（ADC）值（1．33±0．17）与3—4级星形细胞瘤组肿瘤区ADC值（1.17±0．21）比较差异有统计学意义（P〈0．05）。两组瘤周白质FA值与ADC值比较差异均有统计学意义。结论DTI可无创性显示脑自质纤维，且肿瘤区ADC值对星形细胞瘤良恶性分级有重要价值。