MRI评估胃动力的研究进展

随着生活工作压力的增大,胃动力紊乱的发病率呈逐年增长趋势,而胃动力紊乱的主要原因是功能性消化不良,因此胃动力检测有助于功能性胃肠道疾病的诊断和治疗。近几年,MRI新技术和新软件的研发以及随着其在胃肠道疾病诊断方面研究的快速发展,通过使用组织对比剂可获得胃肠道高分辨率图像。目前,大多数研究是在证实该技术在临床应用中的价值及研发数据处理技术,新软件研发可以克服运动伪影,提高图像质量,便于诊断评价。MRI检查技术具有无创伤、无电离辐射、多平面成像等优势,广泛适用于需要重复检查的患者。但是,目前该技术仍未能在胃肠道动力评价中广泛应用。该文主要对胃动力不同检查技术进行比较及MRI评价胃动力方面研究进展进行阐述。     

口服等渗甘露醇MR小肠造影

目的探讨口服等渗甘露醇MRII,肠造影榆台方法及其埘小肠疾病的诊断价值、材料与方法 对临床怀疑小肠疾病的26例患者行MR小肠造影,检查前45min开始分次口服2．5％等渗甘露醇1500ml做为肠道对比剂,MR扫描前静脉注射山莨菪碱20mg抑制肠蠕动．扫描序列包括：平扫：冠状面单次激发快速自旋回波（single—shotFSE,SSFSE）和快速扰相梯度回波（fastspoiledgradientecho,FSPGR）;增强：冠状面和横断面FSPGR序列。记录患者不良反应,以差、良好、优等级评估小肠充盈效果和图像质量,将MR小肠造影诊断结果与手术、病理结果或最终临床诊断对照。结果除2例Crohn病患者感轻度恶心外．被检查者无其他不良反应。26例（100％）回肠和空肠远段、22例（85％）空肠近段充盈效果优良．4例空肠近段充盈效果差。呼吸运动伪影、肠蠕动伪影均为0例．少量磁敏感伪影2例,图像质量均为优、最终诊断结果为正常小肠12例．Crohn病7例,小肠梗阻（肠粘连引起）、腺癌、多发间质瘤（GIST）、十二指肠球炎、十二指肠结肠瘘、空肠乇细血管扩张症和小肠旋转不良各1例.1例空肠毛细血管扩张症MR小肠造影术发现异常,其余MR小肠造影诊断与手术、病理或临床诊断结果一致．诊断准确度为96％。结论口服等渗甘露醇MR小肠造影是一种易行、可靠的小肠检查方法,对诊断小肠Crohn病、肿瘤和肠梗阻具有重要价值。     

肺栓塞的MRI研究现状

肺栓塞是具有潜在生命威胁的疾病,需要及时正确的诊断和治疗。近年来,随着硬件和软件的快速发展,肺栓塞的MRI研究较为热门。作者将肺栓塞的MRI检查技术、常用扫描序列、对比剂以及诊断准确度作一综述,并预测将来可能的发展趋势。     

护理干预在小儿核磁共振检查中的应用

核磁共振成像（MRI）是一种安全又比较先进的影像学检查方法,因其具有鲜明的软组织对比,多参数、多方位的成像优势,以及无骨骼伪影干扰和血管流空效应等特性^[1],特别是没有放射线,对人体没有损害,所以在小儿患者的影像学检查中显示出明显的优越性。但磁共振检查有其弱点,如扫描时信号采集较慢、噪声大,且易产生运动伪影,患儿需较长时间不能随意活动,很难耐受,难以配合。     

儿童核磁共振检查中的护理

随着医学技术的飞速发展,大型医疗设备的普及和应用,医学模式的转变,放射科护理的分工逐渐明确.核磁共振,MRI,是一种安全又比较先进的影像学检查方法,因其具有鲜明的软组织对比、多参数、多方位成像的优势,以及无骨骼伪影干扰和血管流空效应等特性,特别是对人体没有损害,在小儿中枢系统疾病的诊断中已经成为重要的临床检查方法.现将MRI检查中病儿的护理体会报告如下.     

MRI评价胎盘功能的应用进展

近年来,MRI超快速扫描技术不断发展,部分解决了胎动伪影的难题,使MRI在胎儿及胎盘检查中的优势突显,目前已成为超声诊断胎儿及胎盘异常的有力补充。MR T2WI在观察胎盘结构方面具有明显的优势,DWI、MRS等功能成像亦可用于胎盘功能评价,多种MRI扫描技术联合应用可为临床提供更清晰、直观的影像学资料。本文主要对目前MRI评价胎盘功能的临床应用进展进行综述。     

胃癌磁共振成像的研究进展

胃癌是消化系统最常见的恶性肿瘤之一。目前最有效的治疗方法仍然是手术治疗，其疗效取决于正确的术前诊断和分期，目前用于胃癌诊断的主要手段仍然是内镜检查和胃的双对比造影检查。近年来随着影像学设备和技术的不断发展，CT和MRI在胃癌诊断和分期中的应用日趋增多。特别是随着MR快速成像技术的不断发展，不仅提高了图像的清晰度，而且可以进行动态增强扫描，MRI在胃肠道的应用也越来越广泛，MRI已成为胃癌影像学诊断的新领域。     

高场强腹部MRI伪影及补偿技术研究

目的 探讨腹部高场强MRI检查伪影产生的原因及解决方法.方法 行高场强腹部MRI检查图像有不同程度伪影的112例患者,分析其伪影产生原因,并采用不同技术进行补偿.结果 112患者中呼吸运动伪影43例,血管搏动伪影12例,化学位移伪影12例,卷褶伪影18例,磁敏感伪影20例,设备伪影7例,经调整呼吸门控、腹部施加腹带、再次呼吸训练、扫描视野上下施加预饱和带、应用脂肪抑制技术、增加视野、应用过采样技术、去除金属异物、应用螺旋桨扫描技术等方法,98例伪影消失或减轻.结论 针对伪影产生原因改变扫描参数或扫描方法,可减少腹部高场强MRI图像的伪影,提高图像质量.     

胃癌MRI检查的研究进展

胃癌是目前世界上最常见的恶性肿瘤之一，总的5年生存率仍不到20％。目前用于胃癌检测的手段主要是内镜检查和胃的双对比造影检查。近年来随着影像学设备和技术的不断发展，CT和MRI在胃癌诊断和分期中的应用日趋增多。MRI由于其无X线辐射且具有很高的软组织分辨率．在胃癌的监测和分期中具有很多潜在的优势。连续扫描技术的改进已使MRI在胃癌诊断中的价值提升，这些技术包括屏气法快速影像技术、放置腹带、抗蠕动剂的使用和相阵线圈。     

小儿行磁共振检查679例临床护理

磁共振(MRI)已成为适用于小儿的影像学检查的常见方法。但此项检查时间长、噪音大,且需患儿在整个扫描过程中都要保持安静、制动状态,稍有躁动便会引起伪影,影响成像质量。由于小儿制动能力,理解、沟通能力差等,加上患儿躯体疾病、环境改变和对扫描器械的恐惧心理,往往不能顺利地完成MRI的检查。2010年8月～2011年7月,我院共接诊行     

MRI for small bowel diseases

The role of radiologic studies has been well established in the diagnosis and management of patients with small bowel diseases. While small bowel follow-through examination or enteroclysis is widely accepted as the primary imaging method for small bowel investigation, additional cross-sectional imaging studies are often required for an accurate diagnosis and the precise evaluation of the extraluminal disease. Since fast magnetic resonance imaging (MRI) sequences have become available, there is increasing interest in the use of MRI for small bowel evaluation, attributed to its inherent advantages such as the lack of radiation exposure, excellent soft tissue contrast, and direct multiplanar capabilities. In this article, we review the current techniques, clinical applications, and limitations of MRI for the evaluation of patients with small bowel diseases.     

Small-bowel endoscopy

This review of the literature on endoscopy of the small bowel focuses on published reports, and does not include abstracts. The literature was reviewed for the period September 2001 to September 2002. MEDLINE was searched under the topics of "small-bowel endoscopy", "small bowel", "enteroscopy", "obscure bleeding", and "wireless endoscopy", and a hand search was also carried out of the major gastroenterology journals, along with a review of the tables of contents of all journals that could be identified as being related to gastroenterology or gastrointestinal endoscopy. Sonde small-bowel enteroscopy is no longer an option, and has been rightfully retired as an investigation tool for the small bowel. There is still a place for further evaluation of push enteroscopy, as evidenced by the 11 papers published since the last review of small-bowel endoscopy in 2002. In the field of intraoperative enteroscopy, only one series and a handful of case reports have appeared. By contrast, wireless capsule endoscopy of the small bowel has captured the imagination of gastroenterologists throughout the world. Up to 2003, there have not been many published papers concerning this new diagnostic modality, since patients with obscure gastrointestinal bleeding or suspected small-bowel disease are relatively scarce. Large numbers of abstracts concerning capsule endoscopy have been submitted for presentation at major gastroenterology and gastrointestinal endoscopy meetings over the past 2 years, and the enthusiasm for this new technique of small-bowel imaging has increased with reports of its successful application.     

Contrast-enhanced MRI of the small bowel in Crohn��s disease

Recently, magnetic resonance imaging has emerged as a valuable tool in evaluation of small bowel Crohn’s disease. MRI provides several advantages to other imaging modalities, including the lack of ionizing radiation, multiplanar capability, and functional information. Intravenous contrast administration is a routine portion of MR enterography protocol, and aids in detection of disease extent, extramural complications such as fistula and abscess, and assessment of activity. Additionally, promising techniques such as dynamic contrast-enhanced MRI may provide quantitative measures to assess bowel perfusion, which may enhance evaluation of disease activity. This article will provide an overview of the technical aspects of contrast-enhanced MR enterography, describe common pathologic findings involving the small bowel in Crohn’s disease, summarize its role in determination of activity with an emphasis on endoscopic and histologic correlation, and compare its efficacy with other imaging modalities.     

CT and MR enterography in evaluating small bowel diseases: when to use which modality?

MR and CT techniques optimized for small bowel imaging are playing an increasing role in the evaluation of small bowel disorders. Several studies have shown the advantages of these techniques over traditional barium fluoroscopic examinations due to improvements in spatial and temporal resolution combined with improved bowel distending agents. The preference of MR vs. CT has been geographical and based on expertise and public policy. With the increasing awareness of radiation exposure, there has been a more global interest in implementing techniques that either reduce or eliminate radiation exposure. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime or in studies that require sequential imaging time points such as in assessment of gastrointestinal motility. MRI has many properties that make it well suited to imaging of the small bowel: the lack of ionizing radiation, the improved tissue contrast that can be obtained by using a variety of pulse sequences, and the ability to perform real time functional imaging. Moreover, MR modalities allow visualization of the entire bowel, without overlapping bowel loops, as well as the detection of both intra- and extraluminal abnormalities.The intra- and extraluminal MR findings, combined with contrast enhancement and functional information, help to make an accurate diagnosis and consequently characterize small bowel diseases.     

MR colonography in inflammatory bowel disease

Colonography based on magnetic resonance imaging (MRI) appears to be a promising technique for polyp assessment in the colon. Several studies have evaluated this method for colonic assessment in patients with inflammatory bowel disease. We briefly review different methodologies such as dark lumen and bright lumen techniques for abdominal MRI. In addition, recently published studies concerning the sensitivity and accuracy in detecting inflammatory bowel changes in inflammatory bowel disease using MRI are discussed.     

MRI of the abdomen with positive oral contrast agents for the diagnosis of inflammatory small bowel disease

Magnetic resonance imaging (MRI) is being used more often in the evaluation of inflammatory bowel diseases. A prerequisite for adequate image quality is the oral application of contrast medium, which can be administered with different modalities. Positive and negative oral contrast media can be used; in terms of diagnostic efficacy, there appears to be no relevant differences between them. Sequences usually are acquired using breath-hold or respiration-triggered protocols. The underlying principle is visualization of circumscribed thickening of the intestinal wall, which shows a pathologic pattern of contrast medium uptake. The available data suggest that MRI is equally as effective as enteroclysis in the primary diagnosis of Crohn's disease and actually more sensitive in the detection of extraintestinal manifestations such as fistulae or abscesses. Supporters of the method predict that MRI will replace enteroclysis in the long term.     

磁共振口服胃肠道对比剂的进展

本文介绍磁共振口服胃肠道对比剂的发展历史,阐述磁共振口服胃肠道对比剂应具备的特性、分类及其代表产品、可能出现的副作用,着重讨论枸橼酸铁铵制剂作用机制、临床应用研究结果及其意义.     

小肠MR造影

MR小肠造影以其完全没有辐射、良好的软组织分辨率、能够清楚显示小肠腔内外情况而在临床上应用越来越多。作者介绍2种MR小肠造影方法:口服法MR小肠造影检查(MR enterography)和插管法MR小肠造影检查(MR enteroclysis),其中尤以口服法MR小肠造影简单、易行、无痛苦。用对比剂填充小肠、使小肠充分扩张是保证小肠造影取得成功的关键。作者经验是2.5%(等渗)甘露醇溶液为较理想的对比剂。简要归纳了一些常见小肠病变的MRI诊断要点并图示。     

Imaging of the lymphatic system: new horizons

The lymphatic system is a complex network of lymph vessels, lymphatic organs and lymph nodes. Traditionally, imaging of the lymphatic system has been based on conventional imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI), whereby enlargement of lymph nodes is considered the primary diagnostic criterion for disease. This is particularly true in oncology, where nodal enlargement can be indicative of nodal metastases or lymphoma. CT and MRI on their own are, however, anatomical imaging methods. Newer imaging methods such as positron emission tomography (PET), dynamic contrast‐enhanced MRI (DCE‐MRI) and color Doppler ultrasound (CDUS) provide a functional assessment of node status. None of these techniques is capable of detecting flow within the lymphatics and, thus, several intra‐lymphatic imaging methods have been developed. Direct lymphangiography is an all‐but‐extinct method of visualizing the lymphatic drainage from an extremity using oil‐based iodine contrast agents. More recently, interstitially injected intra‐lymphatic imaging, such as lymphoscintigraphy, has been used for lymphedema assessment and sentinel node detection. Nevertheless, radionuclide‐based imaging has the disadvantage of poor resolution. This has lead to the development of novel systemic and interstitial imaging techniques which are minimally invasive and have the potential to provide both structural and functional information; this is a particular advantage for cancer imaging, where anatomical depiction alone often provides insufficient information. At present the respective role each modality plays remains to be determined. Indeed, multi‐modal imaging may be more appropriate for certain lymphatic disorders. The field of lymphatic imaging is ever evolving, and technological advances, combined with the development of new contrast agents, continue to improve diagnostic accuracy. Published in 2006 by John Wiley & Sons, Ltd.     

Inflammatory bowel disease

Significant advances have been made in our understanding of the etiology of inflammatory bowel diseases, particularly with the identification of the first gene mutation associated with Crohn's disease; the treatment arsenal has also been expanded, and some new developments have been seen with regard to diagnosis as well. The importance of endoscopic features in relation to the prognosis has been extensively studied. New ultrasound techniques and magnetic resonance-based imaging are on the verge of modifying the diagnostic approach, particularly during follow-up in Crohn's disease of the small bowel. By contrast, virtual colonoscopy using computed tomography or magnetic resonance imaging does not appear to be of much help. However, the development of these new techniques is continuing rapidly, and an explosion of new information may be expected in the coming years.