三维动态增强磁共振门静脉造影

目的　探讨三维动态增强磁共振门静脉造影 (3DDCE -MRP)的方法及其临床应用价值。方法　共对 35例临床上疑有肝脏疾患的病人进行了 3DDCE -MRP检查 ,用TEST -BOLUS序列测定循环时间 ,然后根据公式 :延时时间 =造影剂循环时间 -1 /4采集时间 ,推算出延时时间。从肘静脉快速推注Gd-DTPA 0 .2mmol/kg,用 3DFLASH序列 (TR/TE 4 .6ms/1 .8ms)屏气冠状位扫描获得 3组三维原始图像 ,行最大信号投影处理。观察 3DDCE -MRP对门静脉正常结构和病理状况的显示情况。结果　35例中 1 0例MRP表现为正常 ,原发性肝癌 1 4例 ,门静脉高压 8例 ,肝血管瘤 3例。 3DDCE -MRP能清晰显示门静脉系正常解剖结构 ,门静脉肝内分支能显示至 4～ 6级 ,能较满意显示门脉内瘤栓及门脉高压症患者的侧枝循环情况 ,并能直观地显示门静脉、肝静脉和下腔静脉的立体关系 ,为临床提供全面的肝脏血管结构。结论　 3DDCE -MRP能很好地显示门静脉结构 ,并能准确地评价门静脉病变     

椎动脉增强磁共振血管造影少量对比剂预注射试验分析

目的验证能否通过年龄、体重、心率等推测对比剂峰值时间,评价少量对比剂预注射试验的应用价值.方法搜集55例椎动脉增强MR血管造影（CEMRA）前少量对比剂预注射试验的有关数据,包括年龄、体重、心率、到达时间、峰值时间、持续时间、峰值信号等,所得数据利用SPSS软件进行直线相关和回归分析.结果年龄（55例,平均年龄62岁,中位年龄59岁）、体重（55例,平均体重63kg）、心率（40例,平均心率73次/min）与对比剂峰值时间（55例,平均峰值时间17.5 s）之间的相关度在α=0.05水平差异没有统计学意义（相关系数r分别为0.231、0.118、-0.046,t值分别为1.728、0.865、-0.284,P值分别为0.090、0.392、0.776）.峰值时间与峰值信号（55例,平均峰值信号472）有显著的负相关（r=-0.322,t=2.56,P=0.016）而与持续时间（49例,平均持续时间10.35 s）有显著的正相关（r=0.658,t=5.99,P=0.000）,峰值信号与体重呈显著负相关（r=-0.356,t=2.77,P=0.008）.峰值信号与峰值时间、体重的直线回归分析结果中,其标准化回归系数b分别为-0.284和-0.322,t值分别为-2.285和-2.590,P值分别为0.026和0.012.结论通过年龄、体重、心率推测对比剂峰值时间不可靠;通过少量对比剂预注射试验,能获得合适的正式扫描延迟时间,并能对正式扫描时对比剂注射流率作及时调整.     

低剂量屏气三维对比增强磁共振肺动脉造影

目的:探讨低剂量屏气三维对比增强磁共振肺动脉造影(3DCEMRPA)的方法及初步应用。方法:18例病人接受3DCEMRPA检查,造影剂用量为每公斤体重0.1～0.15mmol,分别进行增强前、增强后第期、增强后第期三维快速稳态进动(3DFISP)成像,所有图像分别经最大信号强度投影法(MIP)重建。比较增强前后各级肺动脉的信号噪声比(SNR)和对比噪声比(CNR)。结果:所有病例增强后的图像均优于增强前图像。增强后第期图像各级肺动脉的SNR和CNR均较增强前图像有显著升高(P<0.05)。结论:3DCEMRPA作为一种安全直观地评价肺动脉的方法,有着广阔的临床应用价值。     

导航技术三维对比剂增强磁共振冠状动脉成像

目的评价导航技术三维对比剂增强磁共振冠状动脉成像的应用价值。方法应用导航技术三维对比剂增强磁共振血管成像方法,对20例受检者分别进行左、右冠状动脉成像,经后处理获得左、右冠状动脉血管图像。应用信噪比和对比噪声比评价增强前后的冠状动脉图像,并对冠状动脉主干及其主要分支的显示情况进行评价。结果(1)对获得成功的18例冠状动脉图像进行评价,增强前冠状动脉图像的信噪比为26.37±7.02,对比噪声比为14.76±6.97;增强后冠状动脉图像的信噪比为38.87±11.62,对比噪声比为33.72±10.80,经统计学比较,信噪比和对比噪声比增强前后的差异有统计学意义(t=2.91,4.62;P<0.05)。(2)对比剂增强后左、右及左回旋支冠状动脉近中段的显示率为100%,远侧段的显示率分别为94.4%、88.8%、77.8%。结论导航技术三维对比剂增强磁共振冠状动脉成像有较高的信噪比和对比噪声比,应用于临床尚需进一步的对照研究。     

三维动态增强磁共振门静脉造影对门静脉癌栓的诊断价值

目的 :探讨三维动态增强磁共振门静脉造影 ( 3DDCE MRP)对门静脉癌栓的诊断价值。方法 :对 2 6例门静脉癌栓患者行 3DDCE MRP检查 ,观察其门静脉癌栓在 3DDCE MRP上的表现 ,并与常规MRI表现进行比较。结果 :所有 2 6例门静脉显示满意。 3DDCE MRP均显示了癌栓所致相应部位门脉阻塞征象 ,2 1例示肝门部侧支血管 ,形成门静脉海绵样变性。结论 :3DDCE MRP是诊断门静脉癌栓的有效方法 ,尤其在显示由此引起的侧支循环方面有很大优越性。不足在于不能显示癌栓近侧端的范围     

三维对比剂增强MR门静脉成像与直接门静脉造影术对照

目的通过与直接门静脉造影术的比较，评价三维对比剂增强MR门静脉成像（3D CE MRP）的准确性。方法26例患者行3D CE MRP和直接门静脉造影检查。分析3D CE MRP上门静脉主干、肝内左右分支的开放性和侧支循环发生情况，其结果与直接门静脉造影对照，评价两者符合情况，并分析两者不符的原因。结果3D CE MRP和直接门静脉造影显示门静脉主干的结果完全一致。对肝内门静脉分支，有21例2种检查结果符合，但有5例不符。1例肝右叶巨大肿瘤，3D CE MRP显示门静脉右后支闭塞，但直接门静脉造影显示明显狭窄。3例左叶肝癌患者，3D CE MRP显示门静脉左支闭塞，但直接门静脉造影显示其近段狭窄和远端闭塞。另有1例肝癌患者，3D CE MRP显示门静脉左支矢状段小癌栓，而直接门静脉造影却未能显示。除1例脐静脉重开由于扫描范围较小未显示之外，3D CE MRP显示侧支循环的结果和直接门静脉造影相符。结论多数病例，3D CE MRP的显示结果与直接门静脉造影符合。3D CE MRP在鉴别肝内门静脉分支狭窄或闭塞时有一定限度，而在显示门静脉小栓子方面却有优势。     

屏气下二维冠状动脉磁共振血管造影的初步评价

目的：对二维冠状动脉（简称冠脉）磁共振血管造影（ＭＲＡ）在缺血性心脏病中的诊断价值进行初步评价。材料与方法：共１０例患者，全部经过Ｘ线冠状动脉造影（简称Ｘ线冠脉造影）检查，磁共振造影在１．５Ｔ扫描机上应用屏气下、脂肪抑制、心电门控Ｋ空间分段采集快速梯度回波技术对冠脉进行研究。结果：１０例左冠脉主干、左前降支、左旋支和右冠脉近段在ＭＲＡ上均完全显示，其冠脉ＭＲＡ左前降支、左旋支及右冠脉平均显示长度分别为６．７２±３．１６ｃｍ、３．６７±４．８１ｃｍ和７．９３±３．１２ｃｍ。与Ｘ线冠脉造影对照，ＭＲＡ发现具有血液动力学明显改变的冠脉病变（狭窄≥５０％）总的敏感性为６２．５％。结论：屏气下二维冠脉ＭＲＡ能较好显示较长节段的主要冠状动脉，对引起血液动力学明显改变的冠脉病变的显示亦有一定意义。     

门静脉磁共振血管成像技术和临床应用

本文阐述了门静脉磁共振血管成像（ＭＡＲ）的几种主要技术，各自的优缺点和它在临床上的使用价值。     

动态增强磁共振门静脉造影在门脉高压症诊断中的价值

目的:探讨动态增强磁共振门静脉造影(DCE MRP)在门脉高压症诊断中的价值。方法:对门脉高压症组23例和正常对照组15例行DCE MRP检查。观察23例门静脉高压症在DCE MRP上的表现。结果:对照组15例均清楚显示门静脉。门脉高压症表现为门静脉增粗(21例)、脾静脉迂曲扩张(23例);门静脉分支级数减少(18例);门静脉延迟显影(7例);显示侧枝循环静脉(6例);门静脉血栓形成(3例)。结论:DCE MRP是评价门静脉的一项快速无创的技术,可准确显示门静脉高压症门静脉系统的病理改变。     

三维DCE MRA在门静脉和肝脏静脉系统的应用

目的探讨门静脉和肝脏静脉系统三维动态增强磁共振血分成像（3DDCEMRM）检查的最佳技术，评价3DDCEMRA在该系统中的使用价值。方法门静脉和肝脏静脉系统行3DDCEMRA108次，二维（2D）DCEMRA10次。比较两种力法显示门静脉右支的能力，不同层厚对3DDCEMRA显示门静脉右支的影响，并对门静脉、肝静脉和下腔静脉在3DDCEMRA的显示情况以及各种病变的3DDCEMRA表现一分析。结果3DDCEMRA显示门静脉右支级数优于2DDCEMRA（P＜0.05），且层厚越薄，显示分支越细（p＜0.01）。3DDCEMRA能较好地显示门脉主干（显示率93％）、左右分支（88％．97％）、肝静脉（81％）和腔静脉（83％），并能显示多种疾病。结论3DDCEMRA能较好地同时显示门静脉、肝静脉和下腔静脉，在门静脉和肝脏静脉系统多种疾病的显示和诊断方面具有较高使用价值。     

Dose optimization of contrast-enhanced carotid MR angiography

The purpose of this work was to compare the diagnostic performance of a single-contrast or a double-contrast dose of carotid contrast-enhanced MR angiography (MRA). One-hundred nineteen patients (mean age 65±14.4 years) underwent carotid contrast-enhanced MRA with a standardized protocol (repetition time/echo 3.73 ms/1.38 ms, flip-angle 25°, acquisition-time 19 s, voxel size 1.2×1.2×0.9 mm³) on a 1.5-T scanner (Sonata, Siemens-Medical-Systems) using a neck phased-array coil. Contrast agent was administered intravenously at a rate of 3.0 ml/s, either as a single dose (n=57; 0.1 mmol/kg body weight) or as a double dose (n=62; 0.2 mmol/kg body weight) of meglumine gadoterate (0.5 M/l), followed by 30 ml saline. Qualitative image analysis was performed on maximum intensity projections using a five-point scale. Signal intensities were measured at three different vascular levels on both sides to assess the contrast-to-noise ratios (CNRs). Image quality was rated as good or excellent in all cases. A double dose did not influence the efficacy of carotid enhancement (CNR single dose 69.12±19.8; CNR double dose 70.01±20.7; p=0.81) compared with a single dose. In both dose groups the mean CNRs were inversely related to bodyweight, despite adjusted contrast volumes (p=0.0005). Double-dose contrast-enhanced carotid MRA is not superior to single-dose MRA, as overall diagnostic performance and quantitative contrast enhancement are equal. Being more cost-efficient, a single-dose administration of contrast agent is recommended for MRA of the carotid arteries.     

MR胆管水成像和钆贝葡胺增强胆管成像对肝移植供体胆管显示的对照研究

目的 探讨MR胆管水成像(T2WI-MRC)和钆贝葡胺增强后胆管成像(CE-MRC)对肝移植供体胆管显示的差别.方法 32名肝移植供体术前均行T2WI-MRC和CE-MRC检查,以术中胆管造影结果为金标准,对比2种成像方法对肝内外胆管的显示情况,并对胃肠内液体影、呼吸引起的运动伪影进行比较.结果 胆管变异9名,2种检查方法均正确诊断.2种方法均可清楚显示3级肝内胆管,T2WI-MRC有28名(87.5%)能显示肝内3级以上胆管,CE-MRC只有14名(43.8%)可以显示.2名受检者T2WI-MRC显示胆总管不连续,CE-MRC及术中胆管造影显示胆总管正常.T2WI-MRC有6名(18.8%)受检者肠道内液体影响胆管显示,CE-MRC则无一名受检者肠道液体影响胆管显示.呼吸引起的运动伪影2种检查方法均不明显.结论 T2WI-MRC和CE-MRC均可用来评估术前肝移植供体胆管解剖,但CE-MRC受肠道液体影响少,较T2WI-MRC对于肝内3级以上胆管显示具有优势.     

3D contrast-enhanced MR portography and direct X-ray portography: a correlation study

Our objective was to compare 3D contrast-enhanced MR portography (3D CE MRP) on a 1.5-T MR imager with direct X-ray portography. Twenty-six consecutive patients underwent 3D CE MRP with in-plane resolution of 1.4 or 1.8 mm, and direct X-ray portography. The findings of these two methods were evaluated and compared. The main portal vein (PV), right PV with its anterior and posterior segmental branches, and left PV including its sagittal segment were shown clearly without diagnostic problem in all cases on MRP. The main PV appearance was accordant with MRP and X-ray. For intrahepatic PVs, the results agreed in 21 patients but disagreed in 5 patients. In 1 patient with a huge tumor in right liver, the right posterior PV was classified as occluded at MRP, but diffusely narrowed at X-ray. The findings of left intrahepatic PV were discordant in 3 patients with hepatocelluar carcinoma in the left lobe. The MRP demonstrated complete occlusion of the left PVs, whereas X-ray showed proximal narrowing and distal occlusion. In another patient with hepatocelluar carcinoma, a small non-occlusive thrombus involving the sagittal segment of the left PV was seen on MRP but not on X-ray. With demonstration of varices and portosystemic shunts, MRP showed results similar to those of X-ray, except one recanalized para-umbilical vein was excluded from the field of view at MRP due to the patient's limited ability of breathholding. The 3D CE MRP correlated well with direct X-ray portography in most cases, it was limited in distinguishing narrowing of an intrahepatic PV from occlusion, but it showed advantage in demonstrating small thrombus within PV. Electronic Publication     

腹主动脉瘤三维增强MR血管造影的临床价值

目的　评价三维增强磁共振血管造影 (3DCE MRA)及其重建技术在腹主动脉瘤 (AAA)检查中的临床价值。方法　 6 3例临床初诊为AAA的患者行 3DCE MRA及相关MR检查。 3DCE MRA用屏气超快速三维梯度回波序列 (3DFISP) [钆喷替酸葡甲胺 (Gd DTPA) 0 2mmol/kg ,1次扫描时间 18～ 2 0s],工作站上三维重建。观察AAA类型、形态、部位、附壁血栓及与分支血管的关系 ;近端瘤颈、远端流出道形态 ;并根据临床需要测量各部位长度、直径、角度 ;评价图像在制定治疗方案中的作用。结果　 6 3例AAA中 ,5 6例为肾下型 ,5例为近肾型 ,2例为肾上型。动脉瘤平均直径 5 3cm。 3DCE MRA能清楚显示动脉瘤类型、形态 ,近远端瘤颈情况及与分支动脉的关系。根据 3DCE MRA图像 ,临床选择合适的治疗方案。 6 3例中 31例行AAA血管内支架腔内隔绝术 ,3DCE MRA所测得的动脉瘤、近端瘤颈及远端流出道的长度及直径与DSA高度一致 (P >0 1) ;4例行传统人工血管置换术 ;另 2 8例因种种原因仅保守治疗。结论　 3DCE MRA因具有高诊断准确性、无放射性及肾毒性等优势 ,可作为AAA治疗前最主要的影像检查方法 ,具有极高的临床价值     

Dynamic contrast-enhanced subtraction MR angiography in intracranial vascular abnormalities

We present our clinical experience with dynamic contrast-enhanced MR angiography (MRA) with subtraction for assessing intracranial vascular abnormalities. Ten patients with various cerebrovascular disorders underwent dynamic contrast-enhanced MRA on a 1.0-T system. Thirty sections (2 mm) were acquired in 29–30 s. Maximum intensity projection images and subtracted source images were compared with those obtained by conventional angiography. In all cases, the presence or absence of abnormalities in the targeted vessels, as well as the morphology of the sagittal sinuses, was clearly visualized as in conventional angiography, without any obstructions such as hyperintense hematomas or thrombi, or intraluminal turbulence. Although the temporal and spatial resolutions with current hardware are insufficient, these preliminary results suggest that dynamic contrast-enhanced MRA with subtraction may be useful for assessing vascular lesions with hemorrhage or thrombus, and the dural sinuses. Received: 4 November 1998; Accepted: 17 May 1999     

单倍剂量三维动态对比增强MR血管成像诊断肢体软组织血管瘤的价值

目的探讨单倍剂量三维动态对比增强MR血管成像（SD 3D DCEMRA）诊断肢体软组织血管瘤的可行性及其意义。方法测试30例健康志愿者注射单倍剂量钆喷替酸葡甲胺（Gd-DTPA）后Gd-DTPA至股、胭和胫前动脉中段的循环时间（TT）、动脉强化峰值信号强度（SPE）和动脉峰值强化持续时间（DPE）。45例肢体软组织血管瘤和9例神经鞘瘤行常规MRI和SD 3D DCEMRA检查，SD 3D DCEMRA扫描时间10～12S，获取动脉早、晚期及静脉期3期图像。观察、比较血管瘤常规MRI与SD 3D DCEMRA表现，比较血管瘤和神经鞘瘤SD 3D DCEMRA的差异。结果（1）股、胭及胫前动脉TT、SPE和DPE依次分别为（15±5）s、（400±50）、（11．9±2．6）s，（19±7）s、（320±45）、（16．8±3．6）s和（27±10）s、（270±39）、（22．0±6．6）s；3条动脉之间的TT（F=6．91，P〈0．01）、SPE（F=21．21，P〈0．01）及DPE（F=12．10，P〈0．01）差异有统计学意义。（2）血管瘤SD 3D DCEMRA表现：瘤体动态显现，自动脉早期至静脉期瘤体信号逐渐增强、瘤体显影范围增大，动脉早、晚期及静脉期平均瘤体信号分别为0．09、0.49和0．74，各期间差异有统计学意义（F=775．60，P〈0．01）；45例中，A型（动脉早期无显影）24例，B型（动脉早期轻微显影）21例，A型SD 3D DCEMRA3期平均瘤体信号0．43、B型0．46，差异无统计学意义（F=4．57，P〉0．01）。肿瘤供血动脉，显示率100％。（3）常规MRI上未能显示的2例血管瘤，SD 3D DCEMRA上动态显现瘤体和显示供血动脉。（4）神经鞘瘤SD 3D DCEMRA无瘤体动态显现和供血动脉显示。结论应用SD 3D DCEMRA诊断肢体软组织血管瘤是可行的，瘤体动态显现和供血动脉显示是其SD 3D DCEMRA特征。     

Use of three-dimensional segmented flash sequence with magnetization transfer contrast to improve gd-dtpa-enhanced intrahepatic MR portography

Twenty healthy volunteers underwent gadopentetate dimeglumine (gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA))-enhanced MR angiography (MRA) using three-dimensional-segmented fast low angle shot images (FLASH) with magnetization transfer contrast (MTC) pulses. MRA was obtained at 75 seconds (early phase) and 135 seconds (late phase) after bolus injection of Gd-DTPA (MTC+ group) during one period of breath-holding. Within 1 week, MRA without MTC was performed under the same scanning conditions. Visualization of intrahepatic portal branches with these methods was compared in both phases. Portal vein-liver contrast-to-noise ratios were significantly higher in the MTC+ group in both phases. For third-and fourth-order portal branches, visualization was significantly better in the MTC+ group in both phases. Use of three-dimensional-segmented FLASH shortened acquisition time and facilitated imaging during breath-holding and also reduced whole-body average specific absorption rate values. Visualization of intrahepatic portal vein branches was improved by MTC pulses, and effective imaging time was prolonged.