磁共振成像小肠造影在儿童克罗恩病中的应用

近年来儿童克罗恩病发生率呈上升的趋势,其具有起病隐蔽,病程缓慢,反复发作,迁延不愈,治愈难度大等临床特点,早期诊断和随访观察能及时有效的指导治疗,延长患儿的生存期、提高患儿的生存质量.随着MRI技术的不断发展,MR小肠造影技术在克罗恩病中的应用越来越受到重视,其具有安全、无创、无电离辐射等特点,能够检测出早期克罗恩病,并能对病变的活动度、病变的类型和范围做出综合判定.     

单次激发快速自旋回波重T_2W磁共振成像在小肠检查中的应用

目的 :探讨SSFSE重T2W磁共振在小肠影像诊断中的价值和限度。材料和方法 :在2000年～2001年间 ,作者行34例小肠SSFSE重T2W磁共振检查 ,观察小肠在SSFSE重T2W磁共振图像上的表现。结果 :空、回肠的肠腔和黏膜显示良好。结论 :磁共振是小肠影像诊断的有效方法之一     

单次激发快速自旋回波重T2W磁共振成像在小肠检查中的应用

目的;探讨SSFSE重T2W磁共振在小肠影像诊断中的价值和限度。材料和方法：在2000年－2001年间,作者行34例小肠SSFSE重T2W磁共振检查,观察小肠在SSFSE重T2W磁共振图像上的表现。结果：空、回肠的肠腔和黏膜显示良好。结论：磁共振是小肠影像诊断的有效方法之一。     

小肠磁共振水成像检查方法及其诊断价值

目的探讨小肠磁共振水成像检查方法及其对小肠疾病的诊断价值。方法本组28例小肠磁共振水成像。25例检查前30min口服0.9%氯化钠注射液或5%葡萄糖氯化钠注射液1500ml,检查前10min静脉注射山莨菪碱20mg;3例小肠梗阻直接进行小肠磁共振水成像,6例增强扫描。诊断结果与插管法小肠气钡造影结果对照。部分病例经手术、病理证实。结果28例小肠磁共振水成像检查均获得成功,图像质量满足诊断要求。正常小肠10例,Crohn’s病2例,十二指肠乳头癌3例,十二指肠腺瘤样增生1例,十二指肠憩室2例,小肠腺癌3例,回肠息肉1例,空肠间质瘤2例,回肠梗阻3例,小肠系膜扭转1例。18例小肠器质性病变诊断敏感性100%(18/18),特异性77.8%(14/18)。结论磁共振水成像对小肠病变的诊断是一种有效的检查方法。     

小肠疾病的MRI检查

小肠疾病的影像学检查方法虽多，但特异度、敏感度均不很高。近年来，MR成像技术有了很大的发展和进步，使其对小肠疾病的检查成为可能，临床应用范围也日见扩大。本文着重对小肠MRI检查技术、临床应用及诊断诸方面进行详细评述。     

磁共振检查在烟雾病中的应用

目的：评价磁共振检查在诊断烟雾病中的应用价值。方法：回顾分析6例烟雾病患者，每例均有MRI平扫和MRA检查，并跟踪随访。结果：磁共振显示双侧大脑前动脉闭塞2例，双侧大脑前动脉及大脑中动脉均闭塞2例，双侧大脑中动脉闭塞2例，其中3例可显示异常血管网。结论：磁共振检查在烟雾病诊断中独具优势。     

肠道磁共振水成像检查技术探讨

目的 探讨不同对比剂在肠道磁共振成像的应用价值.方法 随机选择无消化系统疾病的健康志愿者20名(年龄20～40岁),采用Siemens Symphony 1.5T磁共振成像系统,分别使用阳性对比剂(水)和阴性对比剂(钡剂)以相同的扫描条件行肠道磁共振成像,比较2种扫描方法所获图像之间的差异(t检验).结果 阳性对比剂(水)所获图像优于阴性对比剂(钡剂),两者之间(分别比较肠道黏膜、肠道袋形、与周围组织的境界对比、伪影有无)存在显著的统计学差异(t值分别为8.04、5.43、5.24、5.32;P值均＜0.01).结论 为了获得清晰满意的肠道磁共振图像,应尽量使用阳性对比剂(水)的检查方法(即肠道磁共振水成像).     

小肠疾病的MRI检查

小肠疾病的影像学检查方法虽多，但特异度、敏感度均不很高。近年来，MR成像技术有了很大的发展和进步，使其对小肠疾病的检查成为可能，临床应用范围也日见扩大。本文着重对小肠MRI检查技术、临床应用及诊断诸方面进行详细评述。     

CBASS序列在磁共振成像检查中的应用

目的：分析研究CBASS(Completely Balanced Steady State)序列在MRI检查应用中的优缺点。方法：经Marconi Proview 0．23T开放式磁共振机CBASS序列和常规序列扫描患者及志愿者共65例，受检部位包括脊椎、头颅、骨关节和盆腔等部位，扫描方位有横轴位、矢状位和冠状位。结果：经CBASS序列与常规序列扫描上述各部位对比观察结果表明，CBASS序列可以更清楚地显示受检部位的解剖结构；能够在保持常规T1加权序列所具有的特征的基础上，还能使脑脊液等液体显示高信号；能够清楚显示骨骼内骨小梁及颅神经等微细结构；盆腔扫描可显示前列腺、精囊腺、子宫等结构，尤其对精囊腺囊状结构、间隔及周围静脉丛结构的显示。结论：CBASS具有较高的组织分辨率，能够更精确地显示各组织结构的微细结构，且具有对流体不敏感，扫描时间较短等特点，具有广阔的临床应用前景。     

小肠磁共振成像的研究进展

影像学检查是诊断小肠疾病的主要检查方法,近年来随着磁共振技术的迅猛发展,磁共振小肠成像临床应用越来越广泛,本文拟从比较影像学、标本及动物实验研究、临床研究等几个方面对小肠的磁共振成像研究状况进行综述,以期对小肠的磁共振检查技术有一个整体的认识。     

Assessment of dynamic contrast enhancement of the small bowel in active Crohn's disease using 3D MR enterography

Purpose

To retrospectively compare the dynamic contrast enhancement of the small bowel segments with and without active Crohn's disease at 3D MR enterography (MRE).

Materials and methods

Thirteen patients (five men, eight women; mean age 41.2 years; range 29-56) were imaged on a 1.5-T MR scanner (Sonata, Siemens Medical) with standard MR sequences after having ingested 1000 ml of a 3% mannitol solution. Subsequently, high resolution 3D gradient-echo (volumetric interpolated breath-hold examination = VIBE) data sets were obtained pre-contrast and 20-40 s, 60-80 s, and 120-140 s after i.v. Gd-DOTA administration (0.2 mmol/kg). Signal enhancement was measured on single slices both in normal and histologically confirmed (12/13) inflamed small bowel wall segments as well as in the aorta, the psoas muscle, and the background to calculate signal-to-noise (SNR) and contrast-to-noise ratios (CNR).

Results

Small bowel wall enhancement was significantly higher (p < 0.05) in inflamed compared to normal segments at 20-40 s (SNR inflamed: 58.7 ± 33.8 vs normal: 36.0 ± 19.8; p = 0.048; CNR inflamed: 34.8 ± 23.4 vs normal: 16.3 ± 11.2; p = 0.017) and at 60-80 s (SNR: 60.3 ± 25.1 vs 41.9 ± 20.0; p = 0.049; CNR: 34.9 ± 15.1 vs 19.3 ± 13.2; p = 0.01) after i.v. contrast administration, respectively. Even at 120-140 s CNR was still increased in inflamed segments (33.7 ± 16.0 vs 18.1 ± 13.2; p = 0.04), while differences in SNR did not attain statistical significance (63.0 ± 26.2 vs 45.3 ± 23.3; p = 0.15).

Conclusion

In active Crohn's disease, histologically confirmed inflamed small bowel wall segments demonstrate a significantly increased early uptake of gadolinium on 3D VIBE sequences compared to normal small bowel segments.     

3.0 T MR扩散张量成像在颈椎病诊断中的应用

目的 探讨3.0 T MR扩散张量成像(DTI)作为一种定量分析方法在颈椎病中的应用价值.方法 21名健康志愿者(对照组)和84例颈椎病患者行颈髓DTI,根据T2WI表现将颈椎病组分为A(单纯硬膜囊受压)、B(颈髓轻度受压)、C(颈髓受压,T2WI可疑高信号)、D(颈髓受压,T2WI信号增高)4组,每组21例,以健康组为对照,分析颈椎病组表观扩散系数(ADC)、分数各向异性(FA)值及本征(λ1、λ2、λ3)值的变化,对所有受检者行颈髓纤维束成像.结果所有受检者DTI显示满意.21名对照组颈髓平均ADC值为(0.78±0.08)×10-3mm2/s,FA值为0.72±0.03,λ1、λ2、λ3值分别为(1.51±0.15)×10-3mm2/s、(0.42±0.09)×10-3mm2/s、(0.41±0.10)×10-3mm2/s.对照组与硬膜囊受压组比较,ADC(q=1.451)、FA(q=1.999)、λ1(q=1.137)值差异无统计学意义(P值均＞0.05),与λ2(q=3.039)、λ3(q=2.982)值差异存在统计学意义(P值均＜0.05).对照组与B、C、D 3个颈髓受压组比较,ADC值的q值分别为7.982、8.532、14.073,FA值的q值分别为12.206、15.889、26.306,λ1值的q值分别为4.601、4.845、6.631,λ2值的q值分别为6.502、11.060、20.480,λ3值的q值分别为9.782、9.416、16.949,差异均存在统计学意义(P值均＜0.01).结论 ADC、FA、λ1、λ2、λ3值是检测颈髓微结构改变的敏感指标.     

MR imaging of the small bowel in Crohn's disease

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 advantage of these techniques over tradition barium fluoroscopic examinations secondary 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 [Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84]. 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 [Froehlich JM, Patak MA, von Weymarn C, Juli CF, Zollikofer CL, Wentz KU. Small bowel motility assessment with magnetic resonance imaging. J Magn Reson Imaging 2005;21:370–75]. A recent study showed that certain subgroups of patients with Crohn's disease may be exposed to higher doses of radiation; those diagnosed at an early age, those with upper tract inflammation, penetrating disease, requirement of intravenous steroids, infliximab or multiple surgeries [Desmond AN, O’Regan K, Curran C, et al. Crohn's disease: factors associated with exposure to high levels of diagnostic radiation. Gut 2008;57:1524–29]. Therefore it has been suggested that techniques that can reduce or eliminate radiation exposure should be considered for imaging [Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84]. Owing to the excellent softtissue contrast, direct multiplanar imaging capabilities, new ultrafast breath-holding pulse sequences, lack of ionizing radiation and availability of a variety of oral contrast agents, MR is well suited to play a critical role in the imaging of small bowel disorders. In this article we will review the technical issues related to the performance of MR enterography and enteroclysis and discuss the role and controversies of using MR in the assessment of inflammatory bowel disease.     

Normal small bowel wall characteristics on MR enterography

Purpose

To assess the normal small bowel parameters, namely bowel diameter, bowel wall thickness, number of folds (valvulae connivientes) per 2.5 cm (in.), fold thickness and interfold distance per small bowel segment (duodenum, jejunum, proximal ileum, distal ileum and terminal ileum) on MR enterography.

Materials and methods

Between September 2003 and January 2008, 280 MR enterography examinations were performed for investigation of known or suspected small bowel pathology. 120 of these examinations were normal. Sixty-five (m = 29, f = 36, mean age = 34 years, range = 17-73 years) of 120 examinations without a prior small bowel diagnosis, with no prior or subsequent abnormal radiology or endoscopy examinations, no prior small bowel surgery and with a minimum 3 years follow-up demonstrating normality were retrospectively evaluated for the described small bowel parameters.

Results

We found the mean diameter of the duodenum to be 24.8 mm (S.D. = 4.5 mm), jejunum to be 24.5 mm (S.D. = 4.2 mm), proximal ileum to be 19.5 mm (S.D. = 3.6 mm), distal ileum to be 18.9 mm (S.D. = 4.2 mm) and terminal ileum to be 18.7 mm (S.D. = 3.6 mm). The number of folds per 2.5 cm varied from 4.6 in the jejunum to 1.5 in the terminal ileum. The fold thickness varied from 2.1 mm in the duodenum to 1.8 mm in the terminal ileum. The small bowel parameters gradually decreased in size from the duodenum to the smallest measurements which were in the terminal ileum. The bowel wall is similar in size throughout the small bowel measuring 1.5 ± 0.5 mm.

Conclusion

These results provide the mean, range of normality and standard deviation of the small bowel parameters per segment on the current population on MR enterography. From our experience, knowledge of these parameters is extremely helpful and essential in the everyday assessment of MR enterography studies.     

MR涎管造影临床研究及应用

目的 评价MR涎管造影的各种序列技术和临床应用。方法 依次采用短时反转恢复序列(STIR)、重T2加权快速自旋回波序列(重T2WIFSE)、单次激发快速自旋回波序列(SSFSE)，厚层扫描，快速采集，于服用维生素C(VitC)前后分别扫描。检查了30例，其中13例为志愿者，17例为可疑涎管异常者。结果 3种序列均能显示正常腮腺和颌下腺主导管。13例志愿者STIR序列均能清晰显示涎管1级和2级分支，2例能显示管径约为0．8mm的末梢分支；重T2WIFSE序列可清晰显示13例志愿者1级分支、10例2级分支；SSFSE序列可显示10例涎管1级分支、6例2级分支。STIR序列能清晰显示患者主导管和涎管1、2级分支；重T2WIFSE序列清晰显示患者12例涎管1级、8例2级分支；SSFSE序列清晰显示患者10例1级分支、4例2级分支。17例可疑异常者，腺体炎症7例，急性炎症主导管稍增粗，末梢导管呈点、球状扩张；颌下腺癌1例，导管受压移位，呈截断状改变；良性肿瘤7例，涎管受压移位，无中断；干燥综合征及涎腺病各1例，涎管未见明显异常。16例患者含服VitC0．2g后5min重复扫描，涎管显示较前增粗。结论 MR涎管造影能清晰显示腮腺和颌下腺导管系统，其中STIR序列能清晰显示导管2级分支，是1种显示涎管的非侵袭性方法，含服VitC后可使唾液分泌增多，从而使涎管显示率增加，具有较高的临床实用价值。     

DWI在鉴别脊椎良恶性病变中的应用价值

目的:探讨DWI在鉴别脊椎良恶性病变中的应用价值。方法:分析经病理和/(或)临床随访证实的脊柱压缩性骨折患者共50例82个病变椎体,其中良性组20例,34个椎体;恶性组30例,48个椎体。选取50例中的正常椎体35例共35节椎体作为对照组。均行MRI常规序列及DWI扫描;分析良恶性病变的DWI信号特点,并定量测定3组椎体的ADC值,进行统计学分析。结果:良性及恶性组病灶DWI序列均可表现为高、等、低或混杂信号,且2组信号表现差异无统计学意义;良性组、恶性组、对照组ADC值分别为(2.23±0.25)×10-3 mm2/s,(1.62±0.27)×10-3 mm2/s及(0.43±0.34)×10-3 mm2/s,经t检验,各组间ADC值差异均有统计学意义(P<0.05)。结论:DWI信号改变不能用于鉴别椎体良恶性病变,而ADC值具有重要的鉴别诊断价值。     

儿童胶质母细胞瘤的 MRI 表现及文献复习

目的：探讨儿童胶质母细胞瘤(GBM)的 MRI 表现,提高对本病的认识。方法收集经手术病理证实的5例儿童 GBM的临床及 MRI 资料,回顾性分析肿瘤发生部位、形态、生长方式、瘤周水肿及信号强化特点。结果5例病灶位于大脑半球4例,小脑半球1例,均占位效应明显,其中跨中线结构生长2例;3例呈类圆形,2例呈不规则形。1例瘤周无水肿,4例瘤周轻-中度水肿。囊性1例,囊实性2例,实性2例;囊性部分呈长 T1长 T2信号,FLAIR 呈低信号,DWI 扩散未受限制;实性部分呈等 T1等 T2信号,FLAIR 呈高信号,DWI 受限呈高信号。增强扫描囊性病变嚢壁呈环形强化,边界清晰;囊实性病变实性部分呈环状、结节样强化;实性病变呈明显不规则、团块样强化。结论儿童 GBM 的 MRI 具有一定的特征性表现,确诊需手术病理证实。     

单指数、双指数模型多b值DWI在胰腺癌的应用价值

目的 探讨单指数、体素内不相干运动成像(IVIM)双指数模型多b值扩散加权成像(DWI)定量参数在胰腺癌的应用价值.方法 应用3.0T磁共振扫描仪对临床或手术证实的37例胰腺癌患者行胰腺多b值DWI.应用单指数、IVIM双指数模型分析多b值DWI,测量胰腺癌和癌周胰腺组织的标准化表观扩散系数(ADCstandard)、纯扩散系数 (ADCslow)、假扩散系数(ADCfast) 和灌注分数(f),并应用独立样本t检验进行统计学分析.结果 胰腺癌的ADCslow值高于癌周胰腺组织的ADCslow值(0.611×10-3 mm2/s vs 0.521×10-3 mm2/s,P=0.037),而胰腺癌的ADCfast和f值低于癌周胰腺组织的ADCfast和f值(5.066×10-3 mm2/s vs 7.188×10-3 mm2/s,P=0.035;55.8% vs 64.0%,P=0.016),差异均有统计学意义.胰腺癌的ADCstandard值和ADCslow值显著正相关(r =0.824,P=0.000);ADCfast值和f值显著负相关(r=-0.558,P=0.000).结论 IVIM-DWI的灌注相关参数(ADCfast、f)和扩散相关参数(ADCslow)可以有效鉴别胰腺癌和癌周胰腺组织,IVIM-DWI是无创性早期诊断和鉴别胰腺癌与癌周胰腺组织的理想方法之一.     

Prognostic role of MRI in determining small bowel Crhon's disease categories: Correlation with response to medical therapy

Crhon's disease is a life-long chronic relapsing condition. Morbidity is high and its incidence and prevalence are increasing worldwide. The purpose of this work is to determine whether magnetic resonance imaging can be used to categorize small bowel Crhon's disease into groups that correlate with response to medical therapy.Twenty-five patients (10 males and 15 females) age range (13–80 years) who had an established diagnosis of Crhon's disease were subjected to magnetic resonance imaging to categorize small bowel Crhon's disease into groups and to correlate these groups with response to medical therapy.Patients without luminal narrowing were more likely to respond to medical therapy (P < 0.0001) than patients with luminal narrowing and hold up (P = 0.007).Patients with mild or marked small bowel intestinal wall enhancement were more likely to respond (P < 0.0001) than those with small bowel abnormalities without enhancement. Our findings would support the use of small bowel MRI as a diagnostic and prognostic tool in the management of patients with small bowel Crhon's disease.