磁共振成像小肠造影

总结小肠MRI检查方法,探讨正常小肠的MRI表现及小肠病变的MRI诊断,以提高小肠疾病的影像诊断水平。     

胃肠道疾病磁共振诊断研究

目的：探讨口服肠道对比剂后，应用常规磁共振扫描，重点MRI件散成像（MRI-DWI）、True-FISP序列对胃肠道疾病的影像学诊断价值。方法：对119例胃肠道疾病患者检查前口服不同对比剂的常规MRI、True-FISP序列及DWI（不同b值．b=600、b=1000）图像进行比较研究分析。结果：发现在DWI序列上．恶性病变在高b值（b=1000）时信号较高．较其它方法更能够明确病变的真实大小。结论：口服铁制剂对比剂后，应用DWI、True-FISP序列对胃肠道疾病的影像学诊断价值较高。     

磁共振大分子对比剂的研究进展

本文综述了大分子磁共振对比剂的作用机理、种类、重点讨论了大分子对比剂作为血池及靶向对比剂的研究进展,并提出了这些对比剂目前存在的总是及可能解决的途径。     

肝脏常见小局灶性病变的Gd~+-EOB-DTPA磁共振增强表现与诊断

目的:Gd+-EOB-DTPA是一种新型肝细胞特异性磁共振对比剂,注药后约50%与常规Gd+-DTPA一样经肾脏排泄,另外约50%被具有正常功能的肝细胞所摄取并排泄入胆道。当采用肝胆特异期扫描并结合反映肝局灶性病灶血供特点的动态增强T1WI扫描时,能够显著提高肝小(≤2.0cm)和微小(≤1.0cm)局灶性占位病灶的检出率及定性诊断符合率,本文就此作一简要介绍。     

磁共振高压注射器在磁共振血管成像中的应用及护理

目的：评价高压注射器在磁共振血管成像中的临床应用价值及护理。材料和方法：对50例病人行磁共振血管成像增强扫描。使用高压注射器经上肢大静脉进行快速大剂量对比团注。造影前预先设置流速、流量及注射时间。结果：50例磁共振血管成像均获成功。结论：磁共振高压注射器可保持足够快的流速和流量。使磁共振血管造影效果满意。     

磁共振大分子对比剂的研究进展

本文综述了大分子磁共振对比剂的作用机理、种类,重点讨论了大分子对比剂作为血池及靶向对比剂的研究进展,并提出这些对比剂目前存在的问题及可能解决的途径.     

磁共振靶向对比剂的研究进展

ＭＲ靶向对比剂是ＭＲ顺磁性或超顺磁性对比剂和特定的载体结合,能够特异地靶向一定的组织或器官,具有高度选择性和特异性,能够确定病变性质。其种类按磁性物质可分为顺磁性或超顺磁性对比剂,载体种类有单克隆抗体、受体蛋白、多聚糖、脂质体、细胞等,不同载体将对比剂靶向目的组织和器官后,呈现不同的病灶和实质器官的对比。本文主要综述肝脏、淋巴结、胰腺、神经组织、肿瘤等的ＭＲ靶向对比剂的应用研究。     

磁共振对比剂不良反应的处理

磁共振成像(MRI)增强用的造影剂gadolinium-die-thylenetriamine Pentaacetic acid(简称Gd- DTPA),商品名为马根维显(德国先灵公司)、磁显葡胺(北京北陆公司)、维影钆铵(广州军大),是一类顺磁性造影剂[1],早在1976年用于动物实验,以后逐渐用于临床,于1987年经美国FDA批准后广泛使用[2].我院自1996年8月磁共振开机以来,使用Gd-DTPA增强扫描3 840人次,现将护理配合中应用Gd-DTPA的安全性、注射剂量、速度及进展等综述如下.     

肝胆特异性磁共振对比剂Gd-EOB-DTPA在肝脏局灶性病变诊断中的应用研究

目的:探讨Gd-EOB-DTPA MRI增强扫描时肝局灶性病变的表现及此新型对比剂的诊断效能,提高对肝脏局灶性病变的诊断准确性。方法:已知或怀疑为肝脏局灶性病变的34例患者共90个病灶,病灶性质依次为肝囊肿20个、肝细胞肝癌16个、胆管细胞癌1个、肝脏转移性肿瘤37个、肝血管瘤9个、退变结节1个、肝脏局灶性结节增生1个、肝细胞腺瘤1个、肝脏炎性病变3个及肝脏淋巴上皮瘤样癌1个。所有患者依次行MRI平扫(抑脂TSE T2WI、抑脂3DVIBE、2DGRE T1WI)、Gd-EOB-DTPA三期(动脉期、门脉期和平衡期)增强扫描(抑脂3DVIBE)及延迟20min肝实质期扫描(抑脂2DGRE T1WI、抑脂TSE T2WI、抑脂3DVIBE)。测量并分析Gd-EOB-DTPA增强前后肝脏和病灶信号变化、病灶-肝脏对比噪声比绝对值(|CNR|)变化情况,并观察病灶Gd-EOB-DTPA增强扫描表现和特征。结果:Gd-EOB-DT-PA增强后各期肝实质信号及病灶-肝脏|CNR|均显著增加(P<0.001)。动脉期、门脉期和平衡期所有病灶符合应用常规含钆(Gd)对比剂时的强化表现和特征;延迟20min肝实质期扫描时,肝脏局灶性结节增生呈等信号-高信号,1个肝细胞肝癌呈相对高信号,其余肝囊肿、肝细胞肝癌、胆管细胞癌、肝脏转移性肿瘤、淋巴上皮瘤样癌、退变结节、肝细胞腺瘤、肝血管瘤和肝脏炎性假瘤等均呈相对低信号。结论:Gd-EOB-DTPA动态增强扫描与延迟肝实质期扫描联合应用,可以提供病变形态、血供、细胞来源及功能等更多相关信息,从而提高诊断信心及诊断准确性。     

磁共振肩关节造影在肩袖完全撕裂诊断的临床应用

目的:探讨磁共振肩关节造影检查对肩袖完全撕裂的诊断价值.方法:回顾性分析54例肩袖完全撕裂MR关节造影及MRI表现,与肩关节镜手术结果对照.结果:54例肩袖完全撕裂病例,MRI诊断的敏感度、特异度及准确度分别是87.03％、50.00％和79.41％;MR关节造影诊断Ⅰ型9例、Ⅱ型21例,其敏感度分别为88.89％、95.24％;特异度分别为97.87％、97.14％;准确度分别为96.43％、96.43％;明显高于常规MRI诊断,差异均有统计学意义(P＜0.05);与关节镜结果对比,其一致性极佳(Kappa=0.841);而对于Ⅲ型肩袖完全撕裂,MR关节造影均不能显示.结论:MR关节造影能较准确判断Ⅰ型、Ⅱ型肩袖完全撕裂范围及程度,是MRI诊断肩袖损伤的有效补充,为临床诊断和治疗能提供更准确的依据,而对于Ⅲ型肩袖完全撕裂,MR关节造影不能显示其损伤部位及程度,无法对其进行诊断.     

Magnetic resonance imaging: Review of imaging techniques and overview of liver imaging

Magnetic resonance imaging (MRI) of the liver is slowly transitioning from a problem solving imaging modality to a first line imaging modality for many diseases of the liver. The well established advantages of MRI over other cross sectional imaging modalities may be the basis for this transition. Technological advancements in MRI that focus on producing high quality images and fast imaging, increasing diagnostic accuracy and developing newer function-specific contrast agents are essential in ensuring that MRI succeeds as a first line imaging modality. Newer imaging techniques, such as parallel imaging, are widely utilized to shorten scanning time. Diffusion weighted echo planar imaging, an adaptation from neuroimaging, is fast becoming a routine part of the MRI liver protocol to improve lesion detection and characterization of focal liver lesions. Contrast enhanced dynamic T1 weighted imaging is crucial in complete evaluation of diseases and the merit of this dynamic imaging relies heavily on the appropriate timing of the contrast injection. Newer techniques that include fluoro-triggered contrast enhanced MRI, an adaptation from 3D MRA imaging, are utilized to achieve good bolus timing that will allow for optimum scanning. For accurate interpretation of liver diseases, good understanding of the newer imaging techniques and familiarity with typical imaging features of liver diseases are essential. In this review, MR sequences for a time efficient liver MRI protocol utilizing newer imaging techniques are discussed and an overview of imaging features of selected common focal and diffuse liver diseases are presented.     

烟雾病的MRI、MRA诊断价值

 目的探讨MRI、MRA对烟雾病(Moyamoya病)的诊断价值.方法对11例Moyamoya病患者行MRI和MRA检查,MRI包括横轴位和矢状位T1WI、T2WI、FLAIR;MRA采用3D TOF法,3例行增强MRA.结果MRI表现为:(1)Moyamoya血管:双侧3例,单侧8例;(2)脑梗死和脑软化灶11例;(3)局部脑萎缩3例.MRA表现为3例双侧颈内动脉狭窄,双侧大脑中、前动脉闭塞,大脑后动脉形成异常血管网;6例右侧颈内动脉、大脑中动脉狭窄;2例左侧颈内动脉、大脑中动脉狭窄.结论MRI能良好的显示脑内病变,MRA能较完整的显示异常血管,MRI与MRA相结合可作为烟雾病诊断的首选检查方法.     

Magnetic resonance imaging of pyomyositis

Pyomyositis is a relatively rare entity in temperate climates. Because of its rarity and its nonspecific clinical and radiographic findings, pyomyositis may be misdiagnosed and may cause severe morbidity and mortality. We present magnetic resonance imaging findings in two cases of pyomyositis. Magnetic resonance imaging was helpful in differentiating other pathological processes from pyomyositis, outlining the extent of involvement, and localizing the fluid collection.     

Magnetic resonance imaging of atherosclerosis

Abundant data now link composition of the vascular wall, rather than the degree of luminal narrowing, with the risk for acute ischemic syndromes in the coronary, central nervous system, and peripheral arterial beds. Over the past few years, magnetic resonance angiography has evolved as a well-established method to determine the location and severity of advanced, lumen-encroaching atherosclerotic lesions. In addition, more recent studies have shown that high spatial resolution, multisequence MRI is also a promising tool for noninvasive, serial imaging of the aortic and carotid vessel wall, which potentially can be applied in the clinical setting. Because of the limited spatial resolution of current MRI techniques, characterization of coronary vessel wall atherosclerosis, however, is not yet possible and remains the holy grail of plaque imaging. Recent technical developments in MRI technology such as dedicated surface coils, the introduction of 3.0-T high-field systems and parallel imaging, as well as developments in the field of molecular imaging such as contrast agents targeted to specific plaque constituents, are likely to lead to the necessary improvements in signal to noise ratio, imaging speed, and specificity. These improvements will ultimately lead to more widespread application of this technology in clinical practice. In the present review, the current status and future role of MRI for plaque detection and characterization are summarized.     

胃肠道阴性对比剂在磁共振胰胆管成像中的应用

目的：评价马根维显（Gd—DTPA）溶液作为胃肠道阴性对比剂对改善磁共振胰胆管成像（MRCP）质量的价值。方法：对30例疑有胰、胆管系统疾病的患者口服对比剂前后分别行常规腹部MR和MRCP检查,采用相同的扫描参数及定位。结果：所有病例口服对比剂后MRCP扫描,胃及十二指肠内液体高信号均较前有明显下降,图像质量明显提高。口服稀释的Gd—DTPA溶液前后,MRCP检查胆总管、胰管及胆囊结构的显示效果具有显著性意义（P〈0．05）。结论：口服稀释的Gd—DTPA溶液是一种安全有效降低胃肠道液体高信号强度、改善MRCP图像质量的方法。     

Magnetic resonance imaging of cartilage and cartilage repair

Magnetic resonance (MR) imaging of articular cartilage has assumed increased importance because of the prevalence of cartilage injury and degeneration, as well as the development of new surgical and pharmacological techniques to treat damaged cartilage. This article will review relevant aspects of the structure and biochemistry of cartilage that are important for understanding MR imaging of cartilage, describe optimal MR pulse sequences for its evaluation, and review the role of experimental quantitative MR techniques. These MR aspects are applied to clinical scenarios, including traumatic chondral injury, osteoarthritis, inflammatory arthritis, and cartilage repair procedures.     

磁共振心肌灌注成像及心肌活力分析诊断急性心肌梗死的价值

目的:研究磁共振心肌灌注成像及心肌活力分析在诊断急性心肌梗死中的价值。方法:选择37例急性心肌梗死患者作为观察组,同时选出37例无心血管疾病的正常志愿者作为对照组,均行灌注成像和心肌活力分析,观察2组相应心肌信号强度平均值、首过最大上升斜率及首过时间。结果:磁共振心肌灌注成像延迟期观察组梗死心肌的信号强度平均值为73.23±35.24,对照组正常心肌(对应观察组梗死区)为17.99±8.15,2组对比差异具有统计学意义(P<0.01);观察组梗死心肌的首过最大上升斜率平均值为32.85±20.69,对照组正常心肌(对应观察组梗死区)为44.68±23.60,2组对比差异具有统计学意义(P<0.01)。观察组患者心肌梗死区首过时间平均为(5.04±1.74)s,对照组正常心肌(对应观察组梗死区)为(2.82±1.82)s,2组对比差异具有统计学意义(P<0.01)。结论:磁共振心肌灌注成像及心肌活力分析可用于诊断急性心肌梗死。     

Magnetic resonance imaging of the liver: New imaging strategies for evaluating focal liver lesions

The early detection of focal liver lesions, particularly those which are malignant, is of utmost importance. The resection of liver metastases of some malignancies (including colorectal cancer) has been shown to improve the survival of patients. Exact knowledge of the number, size, and regional distribution of liver metastases is essential to determine their resectability. Almost all focal liver lesions larger than 10 mm are demonstrated with current imaging techniques but the detection of smaller focal liver lesions is still relatively poor. One of the advantages of magnetic resonance imaging (MRI) of the liver is better soft tissue contrast (compared to other radiologic modalities), which allows better detection and characterization of the focal liver lesions in question. Developments in MRI hardware and software and the availability of novel MRI contrast agents have further improved the diagnostic yield of MRI in lesion detection and characterization. Although the primary modalities for liver imaging are ultrasound and computed tomography, recent studies have suggested that MRI is the most sensitive method for detecting small liver metastatic lesions, and MRI is now considered the pre-operative standard method for diagnosis. Two recent developments in MRI sequences for the upper abdomen comprise unenhanced diffusion-weighted imaging (DWI), and keyhole-based dynamic contrast-enhanced (DCE) MRI (4D THRIVE). DWI allows improved detection (b = 10 s/mm(2)) of small (< 10 mm) focal liver lesions in particular, and is useful as a road map sequence. Also, using higher b-values, the calculation of the apparent diffusion coefficient value, true diffusion coefficient, D, and the perfusion fraction, f, has been used for the characterization of focal liver lesions. DCE 4D THRIVE enables MRI of the liver with high temporal and spatial resolution and full liver coverage. 4D THRIVE improves evaluation of focal liver lesions, providing multiple arterial and venous phases, and allows the calculation of perfusion parameters using pharmacokinetic models. 4D THRIVE has potential benefits in terms of detection, characterization and staging of focal liver lesions and in monitoring therapy.     

关节软骨MR成像进展

随着软骨序列的开发和应用，MRI对关节软骨的评价越来越重要。本文就关节软骨的MRI表现、关节软骨的MRI序列和扫描技术、关节软骨损伤以及修复术后MRI评价等方面进行了综述。     

小肠炎性肌纤维母细胞瘤的磁共振成像诊断及鉴别诊断

目的分析小肠炎性肌纤维母细胞瘤的磁共振成像(MRI)表现,提高对该病诊断的正确性。方法回顾性分析经手术病理确诊并行免疫组织化学检查的11例小肠炎性肌纤维母细胞瘤患者的临床、影像及病理资料,分析其MRI特征(包括平扫及增强)及其与病理特征的联系。结果 (1)11例病灶均单发,位于十二指肠1例、空肠者4例、回肠者4例、空回肠交界处者2例。(2)T1WI为混杂略低信号、T2WI为混杂略高信号、弥散加权成像(DWI)信号为略高混杂信号,5例病灶周围见渗出,增强后呈轻中度逐渐强化者10例,呈均匀中度强化者1例。结论炎性肌纤维母细胞瘤MRI表现多种多样、缺乏特异性,瘤周渗出、增强后呈渐进性强化且有助于提示该病的诊断,但确诊仍需病理学检查。