磁共振脑静脉系血管成像技术及其临床应用

目的探讨磁共振脑静脉系血管成像的技术方法和最佳扫描方案，评价磁共振静脉系血管成像技术(MR venography，MRV)对静脉系疾病的诊断价值及临床意义。方法采用二维时间飞跃法MR血管造影(2D-TOF-MRA)、二维相位对比血管造影(2D-PCA)和三维对比增强MR血管造影(3D-CE-MRA)3种血管成像技术分别对20例健康志愿者和20例临床或MRI疑有静脉系疾病的患者行MRV成像，并采用最大强度投影(MIP)、多平面或曲面重建(MPR)及数字减影MRA(DSMRA)技术对图像进行后处理，观察脑静脉系在MRV中的显示情况及脑静脉系疾病在MRV中表现形式，制定脑静脉系成像的最佳方案。结果本组经3D-CE-MRA静脉系成像诊断为13例颅内静脉窦血栓形成(CVST)及7例颅内肿瘤累及静脉系的阳性显示率为100％，均经临床治疗复诊及手术证实。2D-PCA及2D-TOF-MRA对细小引流静脉显示欠佳，且2D-TOF-MRA对复杂区域内静脉血管亦显示欠佳。结论3D-CE-MRA结合2D-PCA及2D-TOF-MRA静脉成像技术形成全脑静脉系成像，为脑静脉系的最佳成像方案，对临床术前评估和指导治疗有极其重要的意义。     

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     

32通道线圈在3.0 T MR对比增强全心冠状动脉成像中的初步应用

目的 评价32通道线圈高并行采集加速3.0 T MR对比增强全心冠状动脉成像(CECMRA)技术的临床应用价值.方法 对拟诊冠心病的60例患者进行32通道线圈3.0 T CE CMRA检查,成像采用心电门控、呼吸导航、扰相位梯度回波序列,加用非选择性反转回波抑制心肌信号,TT为200 ms.以全心覆盖和并行采集方式获取图像数据.增强扫描采用钆贝葡胺(Gd-BOPTA,0.15 mmoL/kg)慢速静脉注射(0.3 ml/s).以X线冠状动脉造影结果作为参考标准,采用四格表χ2检验,评价CE CMRA诊断冠状动脉≥50%狭窄的诊断准确性.结果 60例患者中56例成功完成3.0 T CE CMRA,平均扫描时间为(6.0±1.3)min.CE CMRA在28例患者正确检出至少1个有意义狭窄,其诊断敏感性为93.3%.在26例CAG除外冠心病的患者中,CMRA正确排除了23例,其诊断特异性为88.5%.结论 应用32通道相控阵线圈行高并行采集加速3.0 T CE CMRA检查,可以在减少对比剂用量的同时缩短扫描时间,提高诊断准确性.     

A comparison of Gd-BOPTA and Gd-DOTA for contrast-enhanced MRI of intracranial tumours

A two-centre intra-individual crossover study was performed in 23 patients with suspected high-grade glioma or metastases to assess and compare the safety and enhancement characteristics of two different MRI contrast media (gadobenate dimeglumine, Gd-BOPTA and gadoterate meglumine, Gd-DOTA) at equivalent doses of 0.1 mmol/kg body weight. T1-weighted spin-echo (SE) and T2-weighted fast SE images were obtained before and T1-weighted images 0, 2, 4, 6, 8 and 15 min after injection. T1-weighted images with magnetisation transfer contrast were acquired 12 min after injection. Qualitative assessment by blinded, off-site readers (reader 1: 19 patients; reader 2: 21) and on-site investigators (23) revealed significant (P 0.005) overall preference for Gd-BOPTA over Gd-DOTA for contrast enhancement (Gd-BOPTA preferred in 18, 15 and 18 cases; Gd-DOTA in 0, 1 and 1 and no preference in 1, 5 and 4; off-site readers 1 and 2, and on-site investigators, respectively). A similar significant preference for Gd-BOPTA was expressed by off-site readers and on-site investigators for lesion-to-brain contrast, lesion delineation, internal lesion structure, and overall image preference. Quantitative assessment by off-site readers revealed significantly (p<0.05) greater lesion enhancement with Gd-BOPTA than with Gd-DOTA at all times from 2 min after injection.     

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.     

Utility of contrast-enhanced 3D turbo-flash MR angiography in evaluating the intracranial venous system

The objective of this study was to compare the effectiveness of contrast-enhanced 3D turbo-flash and 2D time-of-flight (TOF) magnetic resonance angiography (MRA) sequences in the visualization and evaluation of the intracranial venous system. A prospective study was carried out on 41 patients referred to our Magnetic Resonance Imaging (MRI) unit with clinical findings suggestive of dural sinus thrombosis. Contrast-enhanced 3D turbo-flash and 2D TOF MRA sequences were performed, and the dural sinuses and cerebral veins were classified into five grades according to the quality of visualization and presence of thrombosis. We found the dural sinuses and cerebral veins to be normal in all sequences in 31 patients. Thrombosis of dural sinuses was detected in ten patients, with four of these ten cases found only in the contrast-enhanced 3D turbo-flash sequence. In general, complete visualization of cerebral veins and dural sinuses was significantly better accomplished with contrast-enhanced 3D turbo-flash MRA than with 2D TOF in either coronal or sagittal/oblique planes. Although 2D TOF MRA may be superior in detecting chronic dural sinus thrombosis, contrast-enhanced 3D turbo-flash MRA sequences may offer advantages for the early diagnosis and management of acute and subacute dural sinus thrombosis.     

透视触发三维快速梯度回波技术在颅内静脉成像的应用

目的探讨透视触发血管成像技术在脑静脉系统疾病诊断中的价值。方法使用三维快速梯度回波技术（Flash 3D）序列透视触发血管成像,通过调节扫描参数、薄层、高像素,并减少造影剂量等方法,对50例临床怀疑脑内静脉系统病变的患者进行对比增强静脉成像,并评价所获影像中血管主干及分支解剖显示情况。结果50例临床怀疑脑内静脉系统病变患者均成功完成了透视触发Flash 3D序列扫描血管成像,均能满意地显示血管影像,12例未见异常,脑静脉血栓4例,静脉型血管瘤19例,动脉静脉畸形6例,血液病浸润2例,肿瘤压迫及侵犯7例。结论Flash 3D对比增强血管成像能清楚地显示脑部静脉系统及其与病变的关系,为临床对疾病的诊断和治疗提供依据。     

胸部磁共振增强血管造影时对比剂剂量和流率的依赖关系

目的 探讨正常人胸部磁共振增强血管造影(CE MRA)时对比剂剂量和流率的依赖关系。方法 无胸部疾病的正常志愿者61例，按0．08、0．17、0．25和0．33mmol／kg的不同剂量分成4组，再分别以2、3和4ml／s的流率注射对比剂，应用Siemens Vision Plus 1．5T MR系统进行三维动态增强MRA，以评价不同剂量和流率对人胸部血管MR造影的影响，结果 从血管肺组织对比度看，以0．25～0．33mmol／kg对比剂最佳，尤以0．25mmol／kg比较稳定；从2和4ml／s两种流率看，0．33mmol／kg剂量的血管肺组织对比度反而比0.25mmol／kg低，说明血管肺组织对比度并不是随剂量加大而增加的，当剂量达到一定程度时，这种对比度反而会下降。主动脉的强化与肺动脉和肺静脉相比，无论从信噪比还是对比度上均比较稳定，但也随着剂量的升高而逐渐升高，0．17mmol／kg以上基本都能获得较好的强化和对比度，尤其是0．25mmol/kg以上为佳。0．08～0．17mmol／kg剂量时，虽然4ml／s流率的血管肺组织对比度值明显高于2ml／s和3ml／s，但由于对比剂过于浓缩集中在一较短的血管节段内，所以整体图像的主观评价并不理想，达不到诊断要求。结论 胸部血管的CEMRA效果主要与对比剂的注射剂量有关，与流率关系不大。推荐胸部CE MRA对比剂剂量为0．25mmol／kg，以2～3ml／s的流率注射.     

三维动态增强MR血管造影对颅内动脉瘤的诊断价值

目的 评价三维动态增强磁共振血管造影(3D DCE-MRA)在颅内动脉瘤诊断中的价值。方法 对54例高度怀疑有颅内动脉瘤的病人行3D DCE-MRA检查，随后行DSA造影及可行的血管内栓塞治疗。3D DCE-MRA用超快速三维梯度回波序列(3D FISP)(钆喷替酸葡甲胺0．2mmol／kg,1次扫描时间10s)，工作站上三维重建，比较3D DCE-MRA及常规DSA在显示动脉瘤、瘤颈及与载瘤动脉关系上的优劣，及对血管内栓塞治疗的价值。结果 39例脑动脉瘤患者共45个动脉瘤，3D DCE-MRA对动脉瘤的敏感度为96％，特异度73％，准确度90％。3D DCE-MRA对动脉瘤细节及瘤颈的显示明显优于常规DSA，尤其是颈内动脉海绵窦部及椎动脉近小脑后下动脉的动脉瘤，可指导DSA显示动脉瘤方向及预先制定治疗方案。但对周边部及动脉分岔处小动脉瘤的诊断应谨慎。结论3D DCE-MRA能无创有效地诊断颅内动脉瘤，所提供的三维信息对治疗方案的制定具有极大帮助。当诊断有怀疑时，应结合DSA检查。     

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.     

Neurovascular MRI with dynamic contrast-enhanced subtraction angiography

The first generation of digital subtraction MR angiography using thick-slab contrast-enhanced 2D projection techniques has confirmed the potential of MRI to produce noninvasive subsecond angiograms of the craniocervical circulation. As time-resolved techniques become more sophisticated and 3D acquisitions can be obtained with high isotropic spatial resolution we may start to see the demise of catheter angiography as a diagnostic procedure.     

单次屏气三维对比增强磁共振门静脉造影

目的探讨中次收气三维对比增强门静脉造影（3DCEMRP）方法并初步评价其临床应用价值。方法39例病人接受3DCEMBP检查及三维时间飞越法（2DTOF）门静脉成像，其中无肝脏疾患者8例，肝硬化18例，肝癌12例，脾静脉血栓形成1例，Gd-DTPA用量为每公斤体重0.1～0.2mmol，用团注实验剂量确定门静脉峰值通过时间及扫描延迟时间，所有图像分别经最大信号强度投影（MIP）重建，评价门静脉成像质量、开放程度、侧支血管及从静脉曲张的情况。结果门静脉内造影剂峰值通过时间为17～45秒，所有病例3DCE哑MRP成像质量明显优于2DTOF门静脉成像。8例无肝脏疾病者，CEMRP均完整显示门静脉主干及肝内4级以上的分支；18例肝硬化中有17例显示门、脾静脉扩张迂曲，其中10例显示食管胃底静脉曲张，1例门静脉主干近段闭塞，12例肝癌中，5例门静脉主干和（或）其主分支闭塞，6例显示肝内门静脉分支受压、移位；1例脾静脉血栓形成，见脾静脉闭塞及广泛的侧支血管。结论3DCEMRP为一快速、有效评价门静脉系统的检查方法。     

Free-breathing radial volumetric interpolated breath-hold examination vs breath-hold cartesian volumetric interpolated breath-hold examination magnetic resonance imaging of the liver at 1.5T

AIMTo compare breath-hold cartesian volumetric interpolated breath-hold examination (cVIBE) and free-breathing radial VIBE (rVIBE) and determine whether rVIBE could replace cVIBE in routine liver magnetic resonance imaging (MRI).METHODSIn this prospective study, 15 consecutive patients scheduled for routine MRI of the abdomen underwent pre- and post-contrast breath-hold cVIBE imaging (19 s acquisition time) and free-breathing rVIBE imaging (111 s acquisition time) on a 1.5T Siemens scanner. Three radiologists with 2, 4, and 8 years post-fellowship experience in abdominal imaging evaluated all images. The radiologists were blinded to the sequence types, which were presented in a random order for each patient. For each sequence, the radiologists scored the cVIBE and rVIBE images for liver edge sharpness, hepatic vessel clarity, presence of artifacts, lesion conspicuity, fat saturation, and overall image quality using a five-point scale.RESULTSCompared to rVIBE, cVIBE yielded significantly (P < 0.001) higher scores for liver edge sharpness (mean score, 3.87 vs 3.37), hepatic-vessel clarity (3.71 vs 3.18), artifacts (3.74 vs 3.06), lesion conspicuity (3.81 vs 3.2), and overall image quality (3.91 vs 3.24). cVIBE and rVIBE did not significantly differ in quality of fat saturation (4.12 vs 4.03, P = 0.17). The inter-observer variability with respect to differences between rVIBE and cVIBE scores was close to zero compared to random error and inter-patient variation. Quality of rVIBE images was rated as acceptable for all parameters.CONCLUSIONrVIBE cannot replace cVIBE in routine liver MRI. At 1.5T, free-breathing rVIBE yields acceptable, although slightly inferior image quality compared to breath-hold cVIBE.     

Attenuation values of the intracranial arterial and venous vessels by bolus injection of various contrast agents: a study with a single-detector helical CT scanner

Purpose We evaluated the arteriovenous contrast on the source images of intracranial three-dimensional computed tomography (CT) angiography (3D-CTA) using a high-concentration (370 mg I/ml) contrast agent in comparison with intermediate-concentration (300 mg I/ml) contrast. Materials and methods With a fixed intravenous injection rate and scanning delay, 3D-CTA was performed using a single-detector helical CT scanner in 30 consecutive patients. We used 100 ml of iohexol 300 for 10 patients, 100 ml of iopamidol 300 for 10 patients, and 80 ml of iopamidol 370 for 10 patients. Attenuation values of the bilateral internal carotid arteries, bilateral middle cerebral arteries, basilar artery trunk, bilateral cavernous sinuses, bilateral basal veins, and Galenic vein were measured quantitatively on the axial CT angiographic source images. Results High-concentration contrast significantly increased the attenuation values of the intracranial arterial system without increasing the attenuation of the venous system. Conclusion High-concentration contrast is helpful for obtaining valuable arteriovenous contrast on source images with intracranial 3D-CTA.     

肝脏占位性病变的磁共振成像研究：超顺磁性氧化铁与钆喷替酸葡甲胺的比较

通过与常用造影剂钆喷替酸葡甲胺（Gd-DTPA）的配对实验来评价新型造影剂超磁性氧化铁（SPIO）对有肝占位的检出率和定性诊断能力。材料和方法：53个病例132个肝占位首日行平扫及Gd-DTPA的动态增强扫描,次日行SPIO增强扫描,对照病理及临床随访证实结果,探讨各种占位SPIO增强扫描的强化特点,比较平扫联合Gd-DTPA动态增强扫描与平扫联合SPIO增强扫描的病灶检出率和定性诊断率。结果：SPIO增强扫描良性肝占位的信号随肝实质降低,而恶性肝占位的信号保持不变。平扫联合SPIO增强扫描的病灶检出率和定性诊断率较平扫联合Gd-DTPA增强扫描的略高,但统计学上相差不显著。结论：SPIO强化的原理、强化方式直至临床应用方法、特点与Gd-DTPA均完全不同,两者可相互补充和印证,当Gd-DTPA动态增强扫描定性诊断困难时应积极行SPIO增强扫描。     

The importance of adjusting for differences in proximal and distal contrast bolus arrival times in contrast-enhanced iliac artery magnetic resonance angiography

We tested the hypothesis that differences in proximal and distal contrast bolus arrival times may result in insufficient vascular signal in the distal part of the aortoiliofemoral territory with routinely used timing techniques. The difference in arrival time of the contrast medium bolus between the aorta and the common femoral arteries was measured in 14 patients undergoing magnetic resonance angiography of the aortoiliac arteries. A dual-station test bolus technique adjusting for this difference was evaluated. The variation coefficient of the signal intensity in six defined locations and signal intensities (SI) normalised to fat were calculated. Comparisons were made with findings in 13 patients examined with a fluoroscopically triggered timing technique (BolusTrak, Philips Medical Systems, Best, The Netherlands). The difference in bolus arrival time between proximal and distal vessels was 0–7 s. In 3 of 14 patients it was 5.6–7 s. There was a tendency towards a lower mean variation coefficient in the dual-station group (p=0.10). With both techniques, significantly lower SIs were measured in the femoral arteries compared with SIs in the superior part of the abdominal aorta. In two cases in the BolusTrak group, a distal vessel could not be delineated but was shown to be patent on a delayed scan. Differences in contrast medium arrival time along the vessel may be large enough to preclude visualisation of distal vessels unless there is compensation. A dual-station test bolus technique taking this into account was found to be feasible. Electronic Publication     

Cerebral angiography with iohexol a comparison with metrizamide in man

Summary The new non-ionic contrast medium iohexol was compared with Amipaque in selective cerebral angiography in a double blind study in 60 patients. There were no adverse reactions or reports of discomfort during the examinations or in the 24 h follow-up period. No differences were observed with regard to image quality or cerebral circulation time.     

快速注射结合缓慢融入对比剂在冠状动脉MR血管成像中的应用

目的 评价快速注射结合缓慢融入对比剂Gd-DTPA对血池T1弛豫效果的影响.方法 对15例冠心病患者行冠状动脉MRA检查.先以1.50 ml/s流率注射对比剂Gd-DTPA 10 ml,再以0.05 ml/s流率注射20 ml,然后对冠状动脉同1支血管行2次扫描,获得注射对比剂后5和15 min的图像.计算增强前后图像的信噪比(SNR)和对比噪声比(CNR),并以t检验进行比较.结果 注射对比剂后5 min图像的SNR和CNR(35.37±6.84和21. 57±6.08)明显高于增强前图像的SNR和CNR(27.38±6.24和13.19±6.50).注射对比剂15 min后图像的SNR(33.81±9.43)高于增强前,但没有统计学意义(t=1.885,P=0.074),图像的CNR(21.20±7.65)明显高于增强前.注射对比剂后5和15 min图像的SNR和CNR没有明显的区别.结论 快速注射结合缓慢融入Gd-DTPA,可以获得延长短T1效应的采样时间,以适应冠状动脉MRA多期扫描的需求.     

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。     

LAVA CE MRA对正常胰周动脉的评价

目的应用肝脏三维容积超快速多期动态（LAVA）增强MRA研究正常胰腺供血动脉。资料与方法对40例无胰腺及相关疾病者行Gd—DTPA LAVA MR动态增强,经后处理,得到多平面重建图像。观察胰腺各供血动脉,统计其显示率及显示程度。结果胰腺间接供血动脉全部清晰显示,胃十二指肠动脉、胰十二指肠上前动脉显示率大于90％,显示程度平均分值接近或超过2分,胰背动脉显示率62．5％,其余直接供血动脉显示率小于50％,显示程度低于1分。结论Gd—DTPA LAVA MRA能良好地显示胰腺供血动脉。