MR多层面重建对结构测量准确性的影响

目的研究磁共振多层面重建（MPR）对于图像结构测量准确性的影响。方法对MR成像测试体模进行常规MR平扫;对磁共振三维扫描（3DT1MPRAGE）序列进行三维扫描并采用MPR方式进行图像重建。分别测量图像层厚、线性度等参数。结果MPR重建图像层厚和空间线性测量结果与常规MR平扫图像无明显差异。结论MR、3DMPR重建技术对图像测量的准确性没有影响。     

口腔金属材料磁共振成像伪影的实验研究

研究3种口腔常用金属材料在l3种不同头颈部扫描序列中的伪影。测量伪影大小，并进行统计学分析。得出3种金属在相同序列成像中，纯钛伪影最小，硬质钴铬合金伪影最大；相同金属材料，6种自旋回波及快速自旋回波序列产生伪影最小，3种梯度回波序列产生伪影较大，4种平面回波序列伪影最大且使图像变形。口腔金属材料产生伪影与材料类型及成像技术密切相关，通过合理选择金属材料及成像技术得到最佳MR成像。     

磁共振成像液体衰减反转恢复序列诊断老年人脑梗塞

脑梗塞是老年人常见的一种脑血管病,其疗效和预后主要取决于早期准确的诊断.磁共振(MR)成像液体衰减反转恢复(FLAIR)序列对脑梗塞诊断的敏感度高于常规MR成像序列.笔者分析46例脑梗塞患者的MR成像FLAIR序列及常规互旋回波(SE)序列扫描,探讨FLAIR序列诊断老年人脑梗塞的价值.     

MR自旋回波与快速自旋回波脉冲序列对图像质量的影响

目的:探讨双梯度MRl系统在自旋回波SE(spin echo)、快速自旋回波FSE(fast spin echo)成像序列时的成像质量。方法:采用GE双梯度MRI系统和正交发射/接收一体化裂口线圈分别应用SE和FSE脉冲序列,对Magp nan-SMR170MR成像参数测试体模分别行zoom及whole梯度模式扫描。比较两序列成像的图像质量参数。基于Matlab7.0编写程序代码,求图像的信噪比及均匀性、层厚和层间距、几何畸比率等图像参数;空间分辨率直接在MRI的工作站显示器上读取结果:在SE序列成像时,均匀性、层厚误差、层间距误差、垂直方向的几何畸变率,空间分辨率图像质量参数优于FSE成像序列(P<0.01);而信噪比及水平方向的畸变率,FSE成像序列优于SE成像序列(P<0.05)。结论:在临床应用中,需要较高精度的病灶测量以及为临床提供手术范围时,要综合考虑各个成像参数,选择成像序列。     

MR/PET联合成像的发展及临床应用

核磁共振成像的结果是解剖性图像,它有较高的空间纹理信息。而正电子发射体层显像是一种功能性成像,它提供了人体生理代谢信息。MR/PET多模态图像集成了两者成像的优势,可以提供更多图像细节,已开始应用于临床诊疗中。本文介绍了MR/PET联合成像的发展历史、现状及趋势,并呈现了MR/PET在肿瘤诊疗、心血管和脑神经组织显像等方面的临床应用。     

磁敏感加权成像在脑血管畸形诊断中的应用价值

目的 探讨磁敏感加权成像(SWI)在脑血管畸形诊断中的临床应用价值.方法 采用Siemens Sonata 1.5T MR扫描仪的T_1WI、T_2WI及SWI等序列对34例脑血管畸形患者进行前瞻性研究,以数字减影血管造影(DSA)或手术所见为参照标准,将SWI图像与常规MRI图像进行分析比较.结果 34例脑血管畸形患者共41个病灶,包括海绵状血管瘤19例,动-静脉畸形9例,脑静脉畸形6例.SWI图像对脑血管畸形病灶的显示与DSA或手术所见相一致.结论 SWI对脑血管畸形病灶显示清晰、准确.结合其他MR序列可以应用于临床对脑血管畸形的诊断.     

西瓜模拟人脑在CT/MR联合定位立体定向手术中的实验研究

目的:为了克服颅脑CT立体定向手术中软组织分辨率低的不足,而MR立体定向手术的禁忌症较多,探索在脑CT立体定向手术中辅以MR模拟定位的可行性。方法:将5粒鱼肝油丸置入西瓜的不同深处,在MR机上做2mm断层扫描,在CT机上做1mm断层扫描。利用软件进行CT/MR图像配准,测量5个鱼肝油检测点的CT的坐标和MR的坐标,分析检测点CT实测坐标与MR的指示坐标的误差。结果:MR的模拟坐标和CT实际坐标误差<2mm,利用软件配准在MR图像上进行CT立体定向的模拟可视化是可行的。结论:医学图像配准是医学图像处理中的关键技术,CT/MR联合定位具有很重要的临床应用价值。     

低场强磁共振诊断膝关节半月板撕裂的临床应用

目的总结分析半月板撕裂在低场强磁共振（MR）中的影像特征,探讨低场强磁共振成像（MRI）对半月板撕裂的鉴别诊断及在基层医院的临床应用价值。方法回顾性分析2011年8月～2013年1月44例经关节镜或手术证实为膝关节半月板撕裂患者的低场强MRI图像。结果 44例病人中,半月板撕裂的MR图像中清晰显示半月板内的线状、条状、星形裂隙样等各序列高信号及半月板截断、半月板游离体及半月板破裂征象。结论低场强MRI可以精确地显示膝关节半月板撕裂及撕裂情况,可以明确排除类半月板撕裂的假阳性,在基层医院低场强MR对于膝关节半月板撕裂有重要的临床应用价值。     

磁共振全脊柱成像技术与临床应用

目的:探讨磁共振全脊柱成像特点与在诊断脊柱、脊髓病变方面的临床价值.方法:采用PhilipsAchieva 1.5T双梯度超导磁共振成像系统,SENSE-Spine线圈,自动移床和无缝拼接技术,对52例临床疑是脊柱及脊髓病变者行全脊柱成像,并对病变局部行高分辨力成像.结果:52例患者均获得了清晰、直观、完整的显示椎管内全段脊髓、脊椎及周围韧带的连续全脊柱MR图像,MR全脊柱成像显示5例正常,30例脊柱病变,17例脊髓病变.结论:MR全脊柱成像明显缩短了扫描时间,图像质量好,定位、定性准确性高,解决了大范围、高分辨力的脊柱成像难题,对脊柱、脊髓多发性、弥漫性病变的诊断有较大价值.     

1.5T磁共振3D-SPACE序列与3D-TSERT序列在MRCP成像中的应用对比

目的：通过MR可变翻转角的三维快速自旋回波（3DsamplingperfertionwithapplicationoptimizedcontrastsUS—ingdeifferentflipangleevolutions,3D～SPACE）序列与三维快速恢复快速自旋回波（3D—TSERetore,3D—TSERT）序列对胰胆管水成像（MRcholangiopancreatgrapgy,MRCP）中的成像质量进行对比,优化MRCP的成像序列。方法：对48位受检者分别用3D—SPACE序列与3D—TSERT序列行MRCP检查,将采集到的影像利用siemens3D软件进行MIP（maxi．umintensityprojection）重建,并对2种图像的显示情况进行分析比较。结果：3D—SPACE序列的MRCP显示肝段胆管、胰管的效果明显优于3D-TSERT—MRCP序列（P〈0．05）,2种成像序列显示左右肝管、肝总管、胆囊、胆总管的效果差异无显著性意义（P〉0．05）。结论：在1．5TMRI检查中,应用3D—SPACE序列的MRCP在检查时间及成像质量上都优于3D—TSE序列。应成为常规MRCP的首选序列。     

Menstrual regulation training and service programs in Bangladesh: results from a national survey

Using nationally representative sample survey data collected in 1986, this study evaluates the training and service programs for menstrual regulation (MR), and estimates the number of MR procedures performed during 1986, in Bangladesh. The results show that most of the MR providers, who received either formal or informal training, were physicians and family welfare visitors (paramedics) employed by the government. They were trained in various aspects of MR performance, including contraindications and complications associated with MR, the techniques of MR performance and follow-up procedures, and maintenance and sterilization of MR equipment. Averages of 20.5 and 13.0 MR procedures were performed by formally and informally trained physicians, respectively, in the three-month period preceding the date of interview. The corresponding average numbers for formally and informally trained family welfare visitors were 11.6 and 9.1, respectively. A total of 241,442 MR cases were estimated to have been performed between August 1985 and July 1986.     

What's new in MR safety: the latest on the safe use of equipment in the magnetic resonance environment

Magnetic resonance (MR) scanners present a unique set of safety risks for the healthcare facility. In the space surrounding an MR scanner, ferromagnetic objects can become deadly projectiles, device cables can become hot enough to cause burns, and medical equipment can cease to function properly. ECRI detailed these risks--and provided recommendations to help healthcare facilities minimize them--in a December 2001 Guidance Article. In this supplement to that article, we detail some recent MR safety developments and offer additional guidance. In particular, we describe changes in the terminology used to characterize the safety of devices in the MR environment, we outline new guidance on MR safe practices published by the American College of Radiology, and we review the safety issues that facilities need to be aware of when implementing 3-tesla (3 T) MR systems. We also present an updated Starter List of medical device models that have been designed for use in the MR environment. In addition, supplementary articles address the use of ferromagnetic detection systems and the selection of a fire extinguisher for use in the MR environment.     

甘肃省农村人口智力低下调查

目的 了解甘肃省农村人口遗传素质现状,探讨甘肃农村智力低下症及干预措施.方法 对本省农村地区采用整群随机抽样的方法进行智力低下病种、患病率及乡村婚姻、生育状况调查,并把调查结果汇总分析.结果 共调查71 665人,发现引起智力低下的遗传病22种,患者175人,总患病率为0.24%.结论 近亲婚配、其他婚姻陋俗、多子女生育、环境污染及国家相关政策与优生措施落实不到位都是引起智力低下症的相关因素.提出改善甘肃农村地区人口遗传素质、降低智力低下症发病率的建议和对策.     

磁共振双回波成像对肝内良、恶性占位病变的鉴别诊断价值

目的：评价磁共振双回波成像在肝内占位性病变鉴别诊断的应用价值。方法：对根据临床表现、生化检查、CT检查及手术病理随机选择肝内良、恶性占位病变各40例，每例均进行SE、T1W、FSET2W及磁共振双回波成像检查，对其磁共振双回波成像信号进行比较。结果：根据磁共振双回波信号的比较、分析，得出其对良性病变的诊断敏感性为85％、特异性为95％，对恶性病变的诊断敏感性为80％、特异性为94％。结论：在肝脏良、恶性病变的鉴别诊断中磁共振双回波成像信号提供了非常有价值的线索。     

Etiological Analysis of Mental Retardation in Children and Their Siblings in Wuchang, Wuhan

MENTAL RETARDATION (MR) is one of the mostfrequent and debilitating neurological handicaps inchildren and one of the few clinically important dis-orders for which the etiopathogenesis is still poorlyunderstood. MR is currently defined as a signifi-cant impairment of cognitive and adaptive functions,with onset before age 18. Recently, the prevalenceof MR in the Chinese population was estimated tobe 1.2%1 in comparison with 1%-10%2 in westerncountries. The prevalence of MR in a large popula-tion in Wuhang (97...     

心衰伴二尖瓣返流患者脑钠肽与左室射血分数等参数的研究

目的:研究慢性心力衰竭(选择心功能Ⅱ、Ⅲ、Ⅳ级)伴中重度二尖瓣返流(MR)患者与无二尖瓣返流心衰患者血浆中脑钠肽(BNP)水平的差异及其与左室射血分数(LVEF)、左室舒张末期内径(LVEDD)之间的相关性。方法:选择心力衰竭患者128例,入院后均经心脏彩超检查。按NYHA分级,Ⅱ级39例,其中伴二尖瓣返流患者19例,无二尖瓣返流患者20例;Ⅲ级55例,其中伴二尖瓣返流患者27例,无二尖瓣返流患者28例;Ⅳ级34例,其中伴二尖瓣返流患者16例,无二尖瓣返流患者18例。采用美国雅培I2000SR全自动化学发光分析仪测定血浆BNP水平。结果:BNP数值、LVEDD及LVEF在NYHA分级Ⅱ、Ⅲ、Ⅳ各组间(包括有、无二尖瓣返流患者)有统计学差异(P<0.05)。BNP数值在NYHA分级Ⅱ级伴有二尖瓣返流及无二尖瓣返流患者之间有统计学差异(P<0.05)。结论:脑钠肽的升高、左室射血分数及舒张末期内径与NYHA分级相关,脑钠肽在NYHA分级Ⅱ级有二尖瓣返流患者中高于无二尖瓣返流患者。     

3.0T磁共振动态增强在肝切除术的临床应用

目的:探讨3.0T磁共振动态增强成像技术及在精准肝癌切除术中的应用价值.方法:使用HDxt 3.0T超导磁共振对63例患者行动态增强检查并作成像质量评价.结果:63例检查患者的腹部动态增强效果满意,血管清晰,病灶明确,其中15例患者经手术证实病变与增强检查显示相符.结论:3.0T磁共振动态增强能够准确显示肝脏血管及病变,对精准肝癌切除术具有指导意义.     

安徽省某乡镇4～17岁儿童精神发育迟滞的现患研究

目的 :描述安徽省某乡镇 4～ 17岁儿童精神发育迟滞 (mental retardation,MR)现患率状况 ,分析不同等级 MR儿童出生缺陷与发育障碍的检出率。方法 :对某农村地区 1个乡镇的 2 4个行政村所有常住人口进行入户调查 ,结合线索调查对所有 4～ 17岁疑似智力低下儿童进行智力筛查 ,阳性者进行韦氏智力测验及社会适应性能力评价 ,共筛查出阳性儿童 10 1人 ,确诊为精神发育迟滞为 83人 ,对检出的精神发育迟滞儿童进行体格检查及问卷调查。结果 :该农村地区 4～ 17岁儿童 MR粗检出率为7.31‰ ,男童检出率为 8.0 6‰ ,女童检出率为 6 .2 7‰。 MR女童中 ,重度 MR的构成要多于男性儿童。 10～ 17岁年龄组 MR儿童中 ,中度以上精神发育迟滞的构成高于 4～ 9岁年龄组。出生缺陷和其它发育障碍在 MR儿童中排往前 5位的依次是 :下肢运动障碍、上肢运动障碍、癫痫、马蹄内翻、视力障碍。新生儿期发热、惊厥、肺炎、新生儿窒息在不同 MR等级儿童中的发生有显著性差异。结论 :研究结果为进一步探讨 MR儿童的致病危险因素及制定相关策略提供了科学依据。     

Tissue glutathione and cysteine levels in methionine-restricted rats

OBJECTIVE: Previously, we demonstrated that lifelong methionine (Met) restriction (MR) increases lifespan, decreases the incidence of aging-related diseases, increases blood glutathione (GSH) levels, and prevents loss of GSH during aging in rats. Our present objective was to elucidate the effects of MR on GSH metabolism and transport by determining the time course and nature of GSH and cysteine changes in blood and other tissues in young and mature rats. METHODS: Male F-344 rats were placed on control (0.86% Met) or MR (0.17% Met) defined amino acid diets at age 7 wk and killed at different times thereafter. MR was also initiated in adult (12-mo-old) rats. RESULTS: Throughout the first 2 mo of MR, blood GSH levels increased 84% and liver GSH decreased 66% in relation to controls. After this period, liver GSH levels remained constant through at least 6 mo. GSH levels also decreased in the pancreas (80%) and kidney (22%) but remained unchanged in other tissues examined after 11 wk of MR. The increase in blood GSH was evident as soon as 1 wk after initiating MR and reached a plateau by 6 wk. A similar increase in erythrocyte GSH levels was observed when MR was administered to mature adult rats. Fasting decreased liver GSH in controls but had no further effect in MR animals. By 1 mo, cysteine levels had decreased in all tissues except brain. CONCLUSION: These results suggest that adaptive changes occur in the metabolism of Met, cysteine, and/or GSH as a result of MR in young and adult rats. These early metabolic changes lead to conservation of GSH levels in most extrahepatic tissues and increased GSH in erythrocytes by depleting liver GSH to a critical level.     

3.0T磁共振动态增强在肝移植术中的应用价值

目的评价3.0T磁共振动态增强成像技术在肝移植术中的应用价值。方法使用HDxt 3.0T超导磁共振仪对161例患者行动态增强检查,并作成像质量评价。结果 152例检查患者的腹部动态增强效果满意,血管清晰,病灶明确;9例肝移植术后检查患者中1例肝动脉狭窄,1例胆总管狭窄,2例胆管吻合口狭窄。结论 3.0T磁共振动态增强能够准确地显示肝脏血管及病变,对肝移植术具有指导意义。