兔颈动脉急性血栓的MRI分子影像学评价

目的 评价纤维蛋白靶向结合MRI对比剂(EP-2104R)对兔颈动脉急性血栓的显示能力,并与非对比增强和Gd-DTPA增强MR进行对比.方法 用颈动脉外部损伤和阻塞的方法制作5只兔颈动脉内血栓模型,在血栓诱导后急性期(6.0 h)进行对比剂EP-2104R注入前及注入后MR扫描,并与组织病理学对比.结果 纤维蛋白靶向对比剂能准确显示血栓,优于非对比增强MRI和Gd-DTPA增强MRI(P<0.001).Gd-DTPA增强后不能提高发现血栓的能力.结论 纤维蛋白靶向对比剂在显示活体内急性血栓方面优于非对比增强和Gd-DTPA增强MRI.     

3.0T MR波谱技术在非酒精性脂肪肝中的临床应用

目的 探讨3.0T磁共振1H-MR波谱(1H-MRS)成像技术在非酒精性脂肪肝(NAFLD)中的临床应用.方法 选取3.0T MR 1H-MRS扫描成功的10例NAFLD患者和10名健康志愿者(正常组),采用Phillips Achieva 3.0T MRS分析软件对采集数据进行处理,测量water和lip波峰、water和lip的波峰值之比、lip的波峰下测得的面积及脂水面积比的变化特征.结果 NAFLD组患者的water峰值、峰下面积与正常组的water的峰值、峰下面积间差异无统计学意义.NAFLD组患者lip的波峰值、lip峰下面积、脂水峰值比和面积比与正常组间的差异均有统计学意义:lip波峰值: (0.40±0.16)a.u.vs (0.06±0.05)a.u., P<0.05;脂水峰值比: (0.53±0.40) vs (0.05 ±0.03), P<0.05;lip峰下面积:(26.28±19.16) vs (2.31±2.00), P<0.05;脂水峰下面积比: (0.58±0.44) vs (0.04±0.03), P<0.05.结论 3.0T 1H-MRS是一种评价NAFLD脂质代谢的重要技术,对检测肝脏脂质代谢的变化具有一定意义.     

5.0T MR心脏成像:与3.0T MR对比

目的 观察5.0T MR用于心脏成像的可行性。方法 前瞻性对3例心脏疾病患者和17名健康志愿者行5.0T及3.0T 心脏MR(CMR)电影序列和黑血序列成像;比较5.0T与3.0T CMR图像质量和伪影程度分级,并分析以其所获左心室参数的一致性。结果 5.0T与3.0T CMR图像质量和伪影程度分级差异均无统计学意义(P均>0.05),基于不同场强电影图像获得的左心室舒张末期容积(EDV)、收缩末期容积(ESV)、射血分数(EF)、每搏输出量(SV)及舒张末期心肌质量(EDM)的一致性均好(ICC均>0.75,P均<0.001)。结论 5.0T MR可用于心脏成像,其电影序列及黑血序列图像质量与3.0T MR相当。     

3.0 T MR动态增强成像在前列腺癌诊断中的应用研究

目的探讨3.0 T MR动态增强成像（DCE-MRI）在前列腺癌诊断中的应用价值。方法收集疑诊前列腺癌者75例,所有患者均行T2WI和DCE-MRI检查。分析比较T2WI和DCE-MRI对前列腺癌诊断敏感性、特异性和准确性的差异,并分析DCE-MRI对前列腺癌的检出率和Gleason评分的相关性。结果前列腺癌患者44例,T2WI和DCE-MRI对前列腺癌诊断的敏感性、特异性和准确性分别为64%和91%、58%和77%、61%和85%。DCE-MRI诊断敏感性和准确性明显高于T2WI（P〈0.01）,而特异性未见明显高于T2WI（P〉0.05）。DCE-MRI对高分化组Gleason评分〈7分的前列腺癌检出率明显低于对中低分化组Gleason评分≥7分的前列腺癌（P〈0.05）。结论和T2WI相比,3.0 T DCE-MRI能明显提高对前列腺癌的诊断敏感性和准确性。而且,DCE-MRI更容易检出中低分化的前列腺癌。     

肩关节3.0T MR扫描技术的临床应用

慢性肩关节疼痛是现代人的常见病.MRI作为一种无创性检查手段,具有较高的软组织分辨力,能够多平面显示肩关节损伤情况.本研究旨在探讨3.0T MR肩关节扫描技术优化后的序列及参数,以获得最佳图像质量,有助于临床诊治.     

脂质体包裹对比剂在MR的应用

MR造影剂对肝脾的增强价值有限,但其被脂质体包裹后,就能作为肝脾特异性对比剂,还可用其作为血池对比剂.通过在脂质体膜上附加抗体或制成PH敏感脂质体,还可以进一步扩大脂质体的应用范围,对肿瘤的影像诊断会更加准确.本文对携带MR对比剂的脂质体的制造方式及最近的进展进行了描述,对其实用性及原理作了简单的介绍.     

正常腕关节3.0T MR多序列成像对比

目的比较3.0T MR多序列成像显示正常腕关节的价值。方法采用GE Signa HDxT 3.0T MR对23只健康腕关节行FSE-FS-PDW、FSE-FS-T2W、T2*GRE、MERGE冠状位扫描,分别计算腕骨间软骨、骨髓、肌肉、TFC的SNR和软骨/骨髓、肌肉/骨髓、三角纤维软骨盘(TFC)/骨髓的对比噪声比(CNR),以四点评分法分析腕关节的TFC、腕骨间软骨、月三角韧带、舟月韧带的能见度。比较各序列诸结构间的SNR、CNR及能见度。结果各序列间腕关节结构的SNR及CNR差异均有统计学意义(P均<0.001),MERGE和T2*GRE显著高于其他序列,FSE-FS-T2W均为最低;各序列两两比较,部分序列显示同一结构差异无统计学意义(P>0.05)。TFC、腕骨间软骨、月三角韧带、舟月韧带的能见度以MERGE最高,FSE-FS-PDW较高,各序列间差异均有统计学意义(P均<0.001);同一结构各序列两两比较,部分序列间差异有统计学意义(P<0.05)。结论 MERGE是显示正常腕骨间软骨、TFC以及月三角韧带、舟月韧带的优选序列,对于诊断腕关节软骨病变可能具有潜在应用价值。     

T2-MATRIX序列在急性下肢深静脉血栓诊断中的应用

目的探讨T2加权的3D可变翻转角三维快速自旋回波(T2 weighted 3D fast spin echo imaging with modulated refocusing flip angles,T2-MATRIX)序列在急性下肢深静脉血栓形成(lower extremity deep vein thrombosis,LEDVT)诊断中的价值,为早期、精确诊疗LEDVT提供新的影像学方法。材料与方法前瞻性连续收集急性期LEDVT患者21例,均于发病后14 d之内进行T2-MATRIX序列成像,同时行3D磁化强度预备梯度回波序列(magnetization prepared rapid acquisition gradient echo,MPRAGE)成像和超声检查。由两名放射科医生在血管节段水平分别对T2-MATRIX和MPRAGE图像进行双盲判读。比较两种序列在血栓长度、面积及血栓信号强度等指标的评价一致性。以MPRAGE和超声为联合参考标准,计算T2-MATRIX序列检出血栓的诊断准确性。结果纳入的21例LEDVT患者中,共计147个血管节段,其中67个血管节段检出血栓。在血管节段水平T2-MATRIX检出LEDVT的敏感性为94.03%,特异性为98.77%,阳性预测值为98.41%,阴性预测值为95.24%,准确性为96.60%。组内相关系数分析和Bland Altman分析显示T2-MATRIX和MPRAGE序列在血栓长度、面积及血管管径定量评估方面具有较强的一致性(P≤0.05),位于一致性界限内的差值分别占总数的98.51%、97.1%和100%。结论 T2-MATRIX序列诊断急性期LEDVT具有较高的诊断准确性,同时还能显示周围软组织水肿程度,是一个新的影像学检查方法,有望用于临床。     

磁共振肿瘤靶向对比剂的研究进展

磁共振显像（magnetic resonance imaging,MRI）是一种无创的显像技术,它能够对解剖结构提供很高的空间分辨率和三维立体成像,并且能够提供体内组织的功能及生理信息;它还能够探测到体内深部组织的异常情况及提供全身显像。     

大范围扩散加权成像在 3.0T MR 应用的初步研究

目的评价3.0T磁共振大范围扩散加权成像（DWI）的可行性和可重复性。方法在3.0T磁共振上采用STIR-DWI序列对10例正常志愿者进行扫描。为研究大范围DWI的可重复性,1周内对志愿者进行2次大范围STIR-DWI扫描,扫描范围从头到小腿,共1664mm,b=800s/mm^2。评价图像的可读性,记录严重变形和出现伪影的部位。应用Functool2软件进行后处理,测量部分正常组织的ADC值,应用配对t检验比较两次大范围DWI上所测组织ADC值的一致性。结果大范围DWI仅在颈部处有轻微的变形和伪影。统计结果表明两次扫描所测组织ADC值一致性较好。结论在3.0TMR扫描仪上行大范围DWI扫描是可行的,且重复性较好,可用于开展临床研究。     

3.0T磁共振冠状动脉成像使用对比剂与不使用对比剂图像质量的定量对比分析

目的：采用定量的方法对比分析3．0T冠状动脉MRA（CMRA）使用和不使用对比剂采集对冠状动脉的显示能力和图像质量。方法：58例患者接受CMRA检查,在CMRA的成像过程中采用了使用（n=28）和不使用（n=30）对比剂采集两种方式。使用Soap-Bubble软件对两种方式采集的CMRA数据进行后处理重建并通过测量冠状动脉各主要分支的长度、直径及血管的锐利度,定量评价CMRA的图像质量。结果使用对比剂采集所获得的CMRA各主要分支的测量值为：长度RCA129mm、LM＋LAD112mm、LCX58mm;直径RCA2．9mm、LM＋LAD2．7mm、LCX2．8mm;血管锐利度RCA65％、LAD55％、LCX48％。不使用对比剂采集的CMRA测量值：长度RCA126mm、LM＋LAD109mm、LCX55mm;直径RCA3．0mm、LM＋LAD2．8mm、LCX3．0mm;血管锐利度RCA58％、LAD52％、LCX45％。统计结果显示二者间的血管锐利度和图像质量评分均存在显著性差异（P〈O．05）,但长度和直径的比较无明显差异（P〉0．05）。结论：CMRA采集过程中使用对比剂具有更好的血管锐利度和图像质量,在CMRA的采集过程中建议尽量使用对比剂采集的方式。     

3.0T磁共振多站式多期相CE-MRA在外周血管病变中的应用

目的探讨3.0T MR多站式多期相三维增强血管造影(CE-MRA)在外周血管病变中的应用价值。方法23例怀疑腹盆及下肢血管病变的病人。在3.0T MR上,自动移床四段多期相动态扫描,分析CE-MRA的图像质量及其对各种血管病变的显示情况。结果全部病例图像显示清晰。其中19例下肢动脉硬化闭塞症病人的627支血管,MRA诊断重度狭窄和闭塞的敏感度与特异度分别为94%和100%,阳性预测值81%,阴性预测值为99%。与DSA的诊断结果符合率是89%。结论3.0T MR多站式多期相CE-MRA,可获得高信噪比及超高分辨率的下肢动脉及静脉图像。具有安全、无创伤性,能准确诊断外周血管性病变。     

Pattern of hemodynamic impairment in multiple sclerosis: dynamic susceptibility contrast perfusion MR imaging at 3.0 T

This study aimed to determine regional pattern of tissue perfusion in the normal-appearing white matter (NAWM) of patients with primary-progressive (PP), relapsing-remitting (RR) multiple sclerosis (MS) and healthy controls, and to investigate the association between perfusion abnormalities and clinical disability. Using dynamic susceptibility contrast (DSC) perfusion MRI at 3 T, we studied 22 patients with clinically definite MS, 11 with PP-MS and 11 with RR-MS and 11 age- and gender-matched healthy volunteers. The MRI protocol included axial dual-echo, dynamic susceptibility contrast enhanced (DSC) T2*-weighted and post-contrast T1-weighted images. Absolute cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were measured in the periventricular, frontal, occipital NAWM and in the splenium of the corpus callosum. Compared to controls, CBF and CBV were significantly lower in all NAWM regions in both PP-MS patients (p values from <0.0001 to 0.001) and RR-MS (p values from <0.0001 to 0.020). Compared to RR-MS, PP-MS patients showed significantly lower CBF in the periventricular NAWM (p=0.002) and lower CBV in the periventricular and frontal NAWM (p values: 0.0029 and 0.022). EDSS was significantly correlated with the periventricular CBF (r=-0.48, p=0.0016) and with the periventricular and frontal CBV (r=-0.42, p=0.015; r=-0.35, p=0.038, respectively). This study suggests that the hemodynamic abnormalities of NAWM have clinical relevance in patients with MS. DSC perfusion MRI might provide a relevant objective measure of disease activity and treatment efficacy.     

3.0T 3D高分辨率对比增强MR血管成像显示豆纹动脉的可行性

目的 观察3.0T 3D高分辨率对比增强MR血管成像(3D HR CE-MRA)显示豆纹动脉(LSA)的可行性。方法 回顾性分析60例因疑诊脑血管疾病而接受头部3.0T 3D HR CE-MRA及数字减影血管造影(DSA)患者,根据年龄将其分为老年组(≥60岁,n=21)和中青年组(＜60岁,n=39)。对3D HR CE-MRA图像进行最大密度投影(MIP)重建,比较3D HR CE-MRA与DSA显示LSA主要分支(直线长度＞5 mm)数目及其长度的差异。结果 3D HR CE-MRA及DSA所示组间双侧LSA主要分支数目之和及LSA长度之和差异均无统计学意义(P均＞0.05)。3D HR CE-MRA与DSA所示左侧LSA及右侧LSA主要分支数目亦均无统计学意义(P均＞0.05);3D HR CE-MRA显示左侧LSA长度及右侧LSA长度均短于DSA。结论 3.0T 3D HR CE-MRA技术可用于显示LSA。     

Dual stack black blood carotid artery CMR at 3T: Application to wall thickness visualization

Background

The increasing understanding of atherosclerosis as an important risk factor for the development of acute ischemic events like ischemic stroke has stimulated increasing interest in non-invasive assessment of the structure, composition and burden of plaque depositions in the carotid artery wall. Vessel wall imaging by means of cardiovascular magnetic resonance (CMR) is conventionally done by 2D dual inversion recovery (DIR) techniques, which often fail in covering large volumes of interest as required in plaque burden assessment. Although the technique has been extended to 2D multislice imaging, its straight extension to 3D protocols is still limited by the prolonged acquisition times and incomplete blood suppression. A novel approach for rapid overview imaging of large sections of the carotid artery wall at isotropic spatial resolutions is presented, which omits excitation of the epiglottis. By the interleaved acquisition of two 3D stacks with the proposed motion sensitized segmented steady-state black-blood gradient echo technique (MSDS) the coverage of the carotid artery trees on both sides in reasonable scan times is enabled.

Results

10 patients were investigated with the proposed technique and compared to conventional transversal DIR turbo spin and gradient echo approaches centered at the height of the carotid bifurcation. In all MSDS experiments sufficient black-blood contrast could be obtained over the entire covered volumes. The contrast to noise ratio between vessel and suppressed blood was improved by 73% applying the motion sensitizing technique. In all patients the suspicious areas of vessel wall thickening could be clearly identified and validated by the conventional local imaging approach. The average assessable vessel wall segment length was evaluated to be 18 cm. While in 50% of the cases motion artifacts could be appreciated in the conventional images, none were detected for the MSDS technique.

Conclusion

The proposed technique enables the time efficient coverage of large areas of the carotid arteries without compromising wall-lumen CNR to get an overview about detrimental alterations of the vessel wall. Thickening of the vessel wall can be identified and the suspicious segments can be targeted for subsequent high-resolution CMR. The exclusion of the epiglottis may further facilitate reduction of swallowing induced motion artifacts.     

眩晕患者基底动脉血流动力学3.0T磁共振研究

目的 应用3.0T MR探讨眩晕患者基底动脉及其供血区脑组织血流动力学情况.方法临床表现为眩晕者及正常志愿者各50例.所有受试者均行颅脑磁共振成像(MRI)、磁共振血管成像(MRA)、快速电影相位对比(Fast CINE PC)及流动敏感交互式反转恢复序列(FAIR)检查,对图像进行后处理,得出流速并计算血流量.测量两侧枕叶、小脑、脑桥、延髓FAIR值.对结果进行统计学分析.结果 病例组基底动脉平均流速、峰值流速及血流量分别为(22.47 ±9.14)、(31.60±13.18) cm/s及(91.14 ±43.92) ml/min,对照组基底动脉平均流速、峰值流速及血流量分别为(31.41 ±5.97)、(44.00±7.84) cm/s及(127.49±28.33) ml/min,以上3项指标病例组均较对照组低,两组比较差异均有统计学意义(平均流速:t=-5.79,P＜0.0001;峰值流速:t=-5.71,P＜0.0001;血流量:t=-4.92,P＜0.0001);病例组、对照组基底动脉供血区脑组织灌注总值分别为882.35±35.22、906.34±36.82,两组比较差异有统计学意义(t=-3.33,P=0.0012).MR扫描脑实质及脑血管无明显异常的眩晕患者基底动脉平均流速、峰值流速及血流量分别为(26.31 ±5.16)、(36.33±6.60) cm/s及(95.38±28.16) ml/min,亦均较对照组低(平均流速:t=-2.72,P=0.0086;峰值流速:t=-3.12,P=0.0027;血流量:t=-3.53,P =0.0008);MR扫描脑实质及脑血管无明显异常的眩晕患者基底动脉供血区脑组织灌注总值为904.00±35.82,与对照组(906.34±36.82)比较差异无统计学意义(t=-0.20,P=0.8427).结论 无论脑实质及脑血管有无缺血性病变,眩晕患者基底动脉血液流速及流量均减低;而基底动脉供血区脑组织灌注情况则因有无缺血性病变而不同.     

Nonpeptide factor Xa inhibitors II. Antithrombotic evaluation in a rabbit model of electrically induced carotid artery thrombosis

SK549 (mol. wt. 546 Da) is a synthetic, selective inhibitor of human coagulation factor Xa (fXa) (K(i) = 0.52 nM). This study compared the antithrombotic effects of SK549 and a series of benzamidine isoxazoline fXa inhibitors with aspirin, DuP 714 (a direct thrombin inhibitor), recombinant tick anticoagulant peptide, or heparin in a rabbit model of electrically induced carotid arterial thrombosis. Compounds were infused i.v. continuously from 60 min before electrical stimulation to the end of the experiment. Values of ED(50) (dose that increases the carotid blood flow to 50% of the control) were 0.12 micromol/kg/h for SK549, 0.56 micromol/kg/h for aspirin, 0.14 micromol/kg/h for DuP 714, 0.06 micromol/kg/h for recombinant tick anticoagulant peptide, and >100 U/kg/h for heparin. The EC(50) (plasma concentration that increased blood flow to 50% of the control) for SK549 was 97 nM. Unlike aspirin and heparin, SK549 was efficacious and, at 1.5 micromol/kg/h i.v. (n = 9), maintained carotid blood flow at 87 +/- 6% of control level for greater than 90 min. Unlike heparin, SK549 inhibited ex vivo fXa activity but not ex vivo thrombin activity. There was a highly significant correlation between K(i) (fXa) and ED(50) of a series of fXa inhibitors (r = 0. 85, P <.001). Therefore, these results suggest that SK549 is a novel, potent, and effective antithrombotic agent in a rabbit model of arterial thrombosis. It is likely that SK549 exerts its antithrombotic effect through selective inhibition of fXa. Furthermore, SK549 may be clinically useful for the prevention of arterial thrombosis.     

3.0T磁共振功能成像对肾上腺良性嗜铬细胞瘤与乏脂腺瘤鉴别的价值评价

目的探讨3.0T磁共振功能成像对肾上腺良性嗜铬细胞瘤和乏脂腺瘤的鉴别价值。方法回顾性分析30例患者34个肾上腺良性嗜铬细胞瘤和乏脂腺瘤的化学位移成像及弥散加权成像,对肾上腺肿块的同反相位信号衰减值(SII)、肾上腺肿块-脾脏信号比(ASR)、表观扩散系数(ADC)值行散点图分析。采用Mann-WhitneyU法对两组间SII、ASR、ADC值进行统计学检验,并通过ROC曲线计算各种定量指标的最佳诊断阈值、敏感性、特异性及曲线下面积(AUC)。结果 22个良性嗜铬细胞瘤,SII平均为3.68%,ASR平均0.96,ADC值平均1.12×10-3mm2/s。12个乏脂腺瘤SII平均为27.74%,ASR平均0.75,ADC值平均1.10×10-3mm2/s。良性嗜铬细胞瘤和乏脂腺瘤的SII、ASR有统计学差异,但ADC值无统计学差异。ROC曲线分析显示,SII诊断乏脂腺瘤的最佳阈值为11.96%,AUC为0.841,其95%的可信区间为0.688～0.994。用SII为11.96%为标准,诊断乏脂腺瘤的敏感性为83.3%,特异性为81.8%。ASR诊断良性嗜铬细胞瘤的最佳诊断阈值为0.90,AUC为0.856,其95%的可信区间为0.698～1.014。用ASR为0.90为标准,诊断良性嗜铬细胞瘤的敏感性为86.4%,特异性为82.3%。结论 3.0T磁共振功能成像可用于肾上腺良性嗜铬细胞瘤、乏脂腺瘤诊断及鉴别诊断。     

ApoE-/-小鼠颈动脉稳定性粥样硬化模型的建立及7.0TMR动态观察

目的 建立ApoE-/-小鼠颈动脉稳定性动脉粥样硬化(AS)模型,并探讨用高场强7.0T小动物MR检测AS的形成过程.方法 对10只ApoE-/-小鼠损伤并阻断一侧颈总动脉血流20 min,之后高脂饮食饲养7周,分别在术后4、7周进行7.0T MR检测与病理学检查.结果 4周后MRI显示患侧均出现不同程度的血管壁高信号,7周后MRI表现为损伤血管高壁信号区增厚并管腔狭窄、不规则,创伤后血管腔面积呈下降趋势.对应病理学检查显示,4周后颈总动脉腔内斑块形成,斑块内泡沫细胞及脂质坏死核心形成,其上覆盖厚纤维帽;7周后斑块内增生的内膜内见广泛钙质沉积.结论 用损伤及高脂饮食方法可成功建立ApoE-/-小鼠稳定期AS模型;高场强7.0T MR可成功检测小鼠颈动脉稳定期粥样硬化的形成过程,进一步研究ApoE-/-小鼠易损斑块提供研究基础.     

动态增强MR成像在不典型肺结核球中的应用

目的:探讨动态增强MRI在不典型肺结核球诊断与鉴别诊断中的应用价值.方法:经手术与临床证实的10例不典型肺结核球患者进行DCE-MRI成像,常规进行T1WI、T2WI和DCE-MRI成像,DCE-MRI采用3D-LAVA技术,总共采集18个时相,每个时相扫描时间控制在5～7s,于注药后10、50 s分别进行两次连续扫描,后间隔30 s扫描直至4 min,而后间隔1 min扫描直至12 min.图像分析时将ROI曲线放置在肿瘤最大层面.按照Schaefer的标准将时间信号强度曲线划分为A～D4种类型,描述不典型肺结核球的曲线类型及信号特点.结果:肺结核球T1WI中8例呈稍低信号,2例呈稍高信号,SI值＞250.MR增强表现三种曲线形式,A型1例;环形强化7例(周边环呈A型,中央区域呈D型);D型2例.环形强化病例双曲线形式,强化环基本完整,2例T2WI即呈双环信号改变.D型病例T2WI呈等低信号.结论:肺MR成像有助于不典型肺结核球的诊断与鉴别诊断,且可能提示肺结核球的演变过程:A型-环形强化-D型.环形强化和D型肺结核球易于作出正确诊断.A型曲线与周围型肺癌相近,抗炎或抗结核后随诊至关重要.