相位对比速度在三维相位对比序列中的评价

对３８例颈部磁共振血管成像（ＭＲＡ）使用三维相位对比序列（３ＤＰＣ），分别选择不同的相位对比速度参数进行血管成像质量的对比，认为各血管所需的最佳相位对比速度是：颈内、颈外动脉６０～７０ｃｍ／ｓ，椎动脉３０ｃｍ／ｓ，颈内静脉３０ｃｍ／ｓ。肯定了此参数在扫描中的作用。     

MRI和MRA对Moyamoya病的诊断价值

目的:探讨磁共振成像(MRI)和MR血管成像(MRA)在Moyamoya病中的诊断价值.方法:回顾性分析4例Moyamoya病患者的MRI和MRA资料.结果:4例患者MRA图像均有不同程度的颈内动脉分叉处的血管狭窄或闭塞,3例基底节区异常网状的血管.MRI上显示了所有患者的脑实质改变和4例颈内动脉分叉处的血管狭窄或闭塞改变,所有患者根据其MR上脑血管的改变均可做出正确的诊断.结论:MRA结合MRI能对Moyamoya病患者做出正确的诊断和较准确的分期,同时可用于Moy-amoya病者的随访检查和术后复查.     

三种TOF法MRA诊断实验性动脉瘤的对比分析

目的：比较分析三种ＴＯＦ法ＭＲＡ的图像质量，以及不同成像技术对动脉瘤的诊断价值。材料与方法：用静脉囊镶嵌法将１８只犬制成三种类型（单侧型、分叉型、末梢型）颈总动脉囊状动脉瘤模型，术后２周分别进行ＩＡＤＳＡ、２ＤＴＯＦ、单层块３ＤＴＯＦ、薄块多层重叠技术（ＭＯＴＳＡ）ＭＲＡ检查。结果：以ＩＡＤＳＡ图像为标准，２ＤＴＯＦ、单层块３ＤＴＯＦ、ＭＯＴＳＡＭＲＡ都能显示动脉瘤的位置、形态、类型、大小、瘤颈、瘤体伸展方向。其中以ＭＯＴＳＡＭＲＡ图像最具评价能力，显示动脉瘤的形态、类型、瘤颈优于２ＤＴＯＦ、单层块３ＤＴＯＦ，不足之处图像有层块梯阶样伪影。三种ＴＯＦ成像技术对动脉瘤内缓慢血流、湍流、血栓、大动脉瘤有不同程度的信号丢失。结论：三种ＴＯＦ法成像技术中，ＭＯＴＳＡ技术最有利于作为临床３ＤＴＯＦ法ＭＲＡ检查颅内动脉瘤的常规成像技术。     

MRI评价肺动静脉瘘

目的　评价MRI、MRA等对肺部血管畸形的临床应用价值。方法　分析了 6例手术或血管造影证实的AVF病例的多种表现 ,其中男 5例 ,女 1例 ,采用 1.0T超导MRI仪 ,体线圈技术。分别行SE、2D TOF、3D TOF及cine MRI多种序列成像 ,共行 3 5次MRI和MRA等检查。结果　 6例AVF中共发现 9个病灶。 2例共 3个病灶在SE序列中可见大小不等流空信号 ,其余为等信号之软组织块影、边缘不规则 ;在梯度回波序列 (2D、3D TOF及cine MRI)中病灶均呈高信号或极高信号影 ,在2D TOF中可见到 5例病灶的供血动脉及 3例引流静脉 ;在 3D TOF中可见到 4例病灶的供血动脉及 2例引流静脉 ;在cine MRI序列中可见到 3例病灶供血动脉及 2例引流静脉 ,且cine MRI可见到 5例病灶内信号强弱变化同心动周期一致。结论　目前 ,MRI多种序列的结合应用 ,可以较准确地诊断AVF ,作为一种无创性诊断方法有一定临床应用价值。     

MRA与DWI联合应用在超急性期大面积脑梗死患者中的价值分析

探析超急性期大面积脑梗死患者联合运用MRA与DWI的临床效果。选择2014年2月~2016年6月期间我院收治的67例超急性期大面积脑梗死患者为研究对象,所有患者均行MRA、DWI以及MRI检查,对比分析检查结果。所有患者均顺利完成检查,结果显示DWI、FLAIR以及T2WI的病灶检出率分别为100%(67/67)、16.42%(11/67)以及0;MRA显示,37例为动脉硬化、30例为靶血管狭窄,且MRA病变血管分布定位与DWI责任病灶相符;同时,脑梗死灶中央区与对侧部位的ADC值比较有统计意义(P0.05)。临床上运用DWI与MRA对超急性期大面积脑梗死患者进行检查,不仅可以提高诊断准确率,还可以将靶血管受累和责任病灶清晰显示出来,为治疗提供依据。     

Panvascular disease – Diagnosis and management

Panvascular disease (PVD) increases significantly the risk for cardiovascular events (myocardial infarction, stroke and cardiovascular death); the more sites affected, the greater the risk of a major cardiac event. Despite its high incidence and severe cardiovascular prognosis, PVD has still not been well studied. History of risk factors and co-morbidities, as well as a detailed physical examination, are mandatory in the initial screening and diagnostic work-up. The ankle-brachial index and various non-invasive imaging methods such as duplex ultrasound, computed tomography or magnetic resonance angiography are used for the diagnosis of atherosclerosis in various vascular beds, while digital subtraction angiography is currently used almost exclusively in association with endovascular procedures. Appropriate utilization of techniques is based on international guidelines and a multidisciplinary discussion for each case.Management of a patient diagnosed with PVD can be very complex. Secondary preventive measures and aggressive medical treatment are needed to reduce excess cardiovascular risk. Whether routine screening for atherosclerosis at various sites in the arterial tree in all or selected patients may alter treatment to improve outcome in these patients has not been shown.In the lack of hard evidence, individualized decision-making is needed with the collaboration of many specialties in a multidisciplinary approach. In general, the more symptomatic lesion or the lesion with the strongest prognostic impact should be treated first. In selected cases combined interventions can be done. Perioperative cardiovascular complications are common in patients with PVD, thus preoperative targeted screening may be needed.Clinical studies are needed to identify more effective approaches to diagnose and treat these patients. A single trial performed so far failed to demonstrate a panvascular screening in patients with severe coronary artery disease. Meanwhile, a multidisciplinary team is often needed to optimize short- and long-term prognosis.     

MRA和CTA应用于颅内动脉瘤诊断中的比较

目的 通过与CTA的对比研究，初步探讨MRA对颅内动脉瘤的显示能力和诊断价值。方法 对14例临床怀疑颅内动脉瘤患者进行MRA和CTA检查，后处理使用最大密度投影（MIP）和容积重建（VR）。以DSA和动脉瘤夹闭术作为参考标准，比较MRA和CTA对颅内动脉瘤的显示情况。结果 在14例中，经选择性DSA和动脉瘤夹闭术证实21个动脉瘤，其中17个动脉瘤CTA和MRA均显示良好，两种检查方法所得瘤颈宽度、瘤体最长径数值比较无显著性差异（P〉0．05）。MRA发现的颅内动脉瘤敏感性为90.5％。CTA为95．2％。结论 MRA具有无创、费用低、无并发症、无放射性损害、空间分辨率高、不用造影剂即可明确诊断的优点，在评估动脉瘤及帮助确定治疗方案等方面能满足临床的需求，可以成为临床筛查大部分颅内动脉瘤的首选方法。     

弥散加权磁共振与磁共振血管成像在急性脑梗死诊断中的临床应用

目的　评价弥散加权磁共振成像 (Diffusion -weightedimaging ,DWI)及磁共振血管成像 (MagneticReso nanceAngiography ,MRA)在脑梗死早期的临床应用价值。 方法　对 3 0例急性脑梗死患者行DWI和MRA检查 ,并与CT、常规MRI的结果进行分析比较。结果　在超早期及早期急性脑梗死中DWI可显示CT及T2 WI不能显示的病灶 ,对于T2 WI能显示的病灶DWI能更清楚、更全面的显示该病灶 ,MRA能快速发现血管病变的部位和程度。结论　DWI与MRA对急性脑梗死的早期诊断十分敏感 ,联合检查可同时显示脑实质和脑血管情况 ,为早期溶栓治疗提供了切实可行的影像学资料     

CT血管成像和三维时间飞跃法MR血管成像对颅内动脉瘤诊断的对比研究

目的：研究比较CT血管成像（CTA）和三维时间飞跃法MR血管成像（3D TOF MRA）对颅内动脉瘤的诊断价值.方法：以数字血管造影（DSA）检查结果作为金标准,回顾性分析78例经DSA确诊为颅内动脉瘤患者的CTA及3D TOF MRA影像资料,比较两种检查方法的图像质量及其对动脉瘤诊断的符合率.结果：78例DSA诊断颅内动脉瘤91个,CTA检出76例,共89个动脉瘤;3DTOF MRA检出71例,共82个动脉瘤,灵敏度分别为97.8％、90.1％,CTA对3 mm以下动脉瘤的检出优于3D TOF MRA（P＜0.05）.结论：CTA对颅内动脉瘤的显示总体上优于3D TOF MRA,但3D TOF MRA具有无对比剂副作用、无辐射及经济的优点,这两种检查方法均可作为筛选内动脉瘤的首选,临床可根据实际情况合理选择.     

New look at renal vasculature: 7 tesla nonenhanced T1-weighted FLASH imaging

Purpose:

To investigate the feasibility of 7 Tesla (T) nonenhanced high field MR imaging of the renal vasculature and to evaluate the diagnostic potential of various nonenhanced T1‐weighted (T1w) sequences.

Materials and Methods:

Twelve healthy volunteers were examined on a 7T whole‐body MR system (Magnetom 7T, Siemens Healthcare Sector) using a custom‐built eight‐channel radiofrequency (RF) transmit/receive body coil. Subsequent to RF shimming, the following sequences were acquired (i) fat‐saturated two‐dimensional (2D) FLASH, (ii) fat‐saturated 3D FLASH, and a (iii) fat‐saturated 2D time‐of‐flight MR angiography (TOF MRA). SNR and CNR were measured in the aorta and both renal arteries. Qualitative analysis was performed with regard to vessel delineation (5‐point scale: 5 = excellent to 1 = nondiagnostic) and presence of artifacts (5‐point scale: 5 = no artifact present to 1 = strong impairment).

Results:

The inherently high signal intensity of the renal arterial vasculature in T1w imaging enabled moderate to excellent vessel delineation in all sequences. Qualitative (mean, 4.7) and quantitative analysis (SNR_mean: 53.9; CNR_mean: 28.0) demonstrated the superiority of TOF MRA, whereas 2D FLASH imaging provided poorest vessel delineation and was most strongly impaired by artifacts (overall impairment 3.7). The 3D FLASH MRI demonstrated its potential for fast high quality imaging of the nonenhanced arterial vasculature, providing homogeneous hyperintense vessel signal.

Conclusion:

Nonenhanced T1w imaging in general and, TOF MRA in particular, appear to be promising techniques for good quality nonenhanced renal artery assessment at 7 Tesla. J. Magn. Reson. Imaging 2012;36:714–721. © 2012 Wiley Periodicals, Inc.