先天性心脏病复杂畸形MRI与B超及X线血管造影的影像学对比研究

目的 评估磁共振成像（ＭＲＩ）对先天性心脏病复杂畸形的显示能力。材料与方法 ２１例先天性心脏病复杂畸形患者行磁共振平扫、电影检查,其中８例接受动态增强磁共振血管造影检查（ＤＣＥ－ＭＲＡ）,影像资料与Ｂ超、Ｘ线血管造影检查（ＣＡＧ）对比,部分结果进行统计学处理,１５例经手术证实者对照手术所见。结果 共发现心脏及大血管畸形５５处,磁共振成像、Ｂ超和ＣＡＧ均能很好显示心脏、心肝与大血管连接部分畸形;心脏     

增强MRA在急性肺栓塞诊断中的应用

目的 评价增强磁共振血管造影（ＣＥ ＭＲＡ）诊断急性肺栓塞的价值。材料与方法 对１１例疑有急性肺栓塞的患者进行肺部ＤＳＡ和ＣＥ ＭＲＡ检查。ＣＥ ＭＲＡ检查时,嘱患者屏气,于静脉内团注钆－喷替酸葡甲胺（Ｇｄ－ＤＴＰＡ）对比剂后行肺动脉期扫描,用３Ｄ自由感应衰减的射频扰相稳态梯度召唤回波序列采集图像。所有ＣＥ ＭＲＡ图像由２位ＭＲ诊断医师独立评估,并与ＤＳＡ诊断结果对比。结果 １１例患者中,ＤＳＡ发     

三维增强磁共振肺动脉血管造影诊断急性肺栓塞的实验研究

目的 探讨钆喷替酸葡甲胺（Ｇｄ－ＤＴＰＡ）三维增强共振肺动脉血管造影成像（３ＤＣＥＭＲＰＡ）在急性肺栓塞（ｐｕｌｍｏｎａｒｙ ｅｍｂｏｌｉｓｍ,ＰＥ）中的诊断价值。方法 对１７只自体血栓引发的犬急性肺栓塞模型,利用３Ｄ快速扰相梯度回波序列（ＦＳＰＧＲ）行３Ｄ ＣＥＭＲＰＡ检查和Ｘ线肺动脉血管造影（Ｘ－ｒａｙ ｐｕｌｍｏｎａｒｙ ａｎｇｉｏｇｒａｐｈｙ,ＸＰＡ）检查,并与病理解剖对照。     

磁共振脑血管造影与数字减影血管造影的比较

通过对５５例脑血管磁共振血管造影（ＭＲＡ）和动脉数字减影血管造影（ＩＡ－ＤＳＡ）的对比分析，探讨了ＭＲＡ在颅内血管病变诊断中的可靠性。结果表明，ＭＲＡ可以对４８例患者做出正确诊断，结合常规ＭＲＩ和ＭＲＡ原始切层图像，其敏感性为９０．９％。对动脉瘤的敏感性为８７．５％，动静脉畸形为７８．６％。３例血管狭窄闭塞性病变和１例脑膜瘤患者的血管改变也与ＤＳＡ完全符合。可以认为，作为一种常规筛选工具，ＭＲＡ用于脑血管病变的检查和诊断，具有安全、可靠和方便的优点。     

DCE-MRA在腹部大血管中的应用初探

目的 探讨动态增强磁共振血管造影（ｄｙｎａｍｉｃ ｃｏｎｔｒａｓｔ－ｅｎｈａｎｃｅｄ ＭＲ ａｎｇｉｏｇｒａｐｌｈｙ,ＤＣＥ－ＭＲＡ）在腹部大血管疾病中的应用价值。槽糕与方法 肾性高血压或大动脉炎患者７例,均行ＭＲＩ平行及ＤＣＥ－ＭＲＡ检查中,其中４例行血管造影（ｄｉｇｉｔａｌ ｓｕｂｔｒａｃｔｉｏｎ ａｎ－ｇｉｏｇｒａｐｈｙ,ＤＳＡ）检查。结果 ＤＣＥ－ＲＭＡ可显示肾动脉变细６处,肾动脉受压１处     

腔静脉三维动态增强磁共振血管成像

目的 评价三维动态增强磁共振血管成像（３Ｄ ＤＣＥ ＭＲＡ）用于诊断腔静脉病变的价值。方法 ５２例疑有腔静脉畸形、血栓形成、狭窄、闭塞或受压的患者接受了３Ｄ ＤＣＥ ＭＲＡ成像检查。分析３Ｄ ＤＣＥ ＭＲＡ的图像质量及其对各种腔静脉病变和侧支循环的显示情况,并把３３例３Ｄ ＤＣＥ ＭＲＡ同常规腔静脉造影术（１５例）和手术（１８例）进行比较。结果 ５２例３Ｄ ＤＣＥ ＭＲＡ图像均无伪影,血管显示清楚     

蛛网膜下腔出血患者的MRA和DSA的对照研究

目的：研究ＭＲ血管造影（ＭＲＡ）在蛛网膜下腔出血（ＳＡＨ）患者病因诊断中的应用准确性和可靠性。材料和方法：回顾性分析３３例ＳＡＨ患者的ＭＲＡ资料，并与ＤＳＡ作了对比分析，ＭＲＡ采用三维时间流逝（３Ｄ－ＴＯＦ）法。结果：ＭＲＡ上显示了２６例血管病变中的２２例，包括１５个动脉瘤中的１３个，８例动静脉畸形中的６例和３例血管狭窄闭塞性病变。１个完全血栓形成的右颈内动脉瘤ＭＲＡ上未显示。但常规ＭＲＩ和ＭＲＡ原始图像上显示，ＭＲＡ结合ＭＲＩ和ＭＲＡ原始图像可以对９１％的患者做出正确诊断和评价，动脉瘤和周围血管的关系及ＡＶＭ的供血动脉和畸形结节能在ＭＲＡ上被准确评价。结论：作为一种非损伤性的血管成像方法，ＭＲＡ具有安全、可靠和方便的优点，可以做为常规用于ＳＡＨ患者的筛选检查。     

三维增强磁共振肺动脉血管造影诊断肺动脉血栓栓塞

目的 探讨三维增强ＭＲ肺动脉血管造影（３Ｄ ｃｏｎｔｒａｓｔ－ｅｎｈａｎｃｅｄ ＭＲ ｐｕｌｍｏｎａｒｙ ａｎｇｉｏｇｒａｐｈｙ,３Ｄ ＣＥＭＲＰＡ）诊断肺动脉血栓栓塞的价值。方法 肺动脉栓塞患者１２例,共行１７次３Ｄ ＣＥＭＲＰＡ,其中４例５次于３Ｄ ＣＥＭＲＰＡ当天进行了选择性肺动脉ＤＳＡ。静脉注射钆喷替酸葡甲胺０．２ｍｍｏｌ／ｋｇ后,屏气获得２４层肺血管连续冠状面像,以最大强度投影法（ＭＩＰ     

MR泪道造影的初步研究

目的 探讨ＭＲ泪道造影（ＭＲＤ）技术和应用价值。方法 ２０例正常人和８例慢性泪囊炎（ＣＤ）患者共５３侧泪接受了ＭＲＤ检查,扫描序列为三维稳态构成干扰序列（３Ｄ ＣＩＳＳ）和快速自旋回波（ＴＳＥ）。统计ＭＲＤ的显影结果,并对ＭＲＤ图像进行分析。结果 ３Ｄ ＣＩＳＳ序列ＭＲＤ,４０侧正常泪道显像２２侧,１３侧ＣＤ泪道显像１１例。３Ｄ ＣＩＳＳ序列较好地显示了正常人和ＣＤ患者泪道形态。ＴＳＥ序列ＭＲＤ对     

磁共振胰胆管造影的临床应用

目的：开发磁共振胰胆管造影（ＭＲＣＰ）的应用。材料和方法：采用ＧＥ超导０．５Ｔ，Ｖｅｃｔｒａ２磁共振成像仪，快速自旋回波（ＦＳＥ）重Ｔ２加权扫描及最大强度投影（ＭＩＰ）重建图像。对１１例胰胆病变患者作ＭＲＣＰ检查。结果：１１例均清楚显示胆系结构，结石或肿瘤所造成的充盈缺损或梗阻部位均能准确显示。１例胰头癌还同时清楚可见扩张的胰管。结论：磁共振胰胆管造影（ＭＲＣＰ）有很好的临床应用价值     

Congenital diseases of the thoracic aorta. Role of MRI and MRA

Aortic malformations may be associated with other congenital heart abnormalities or may present independently, as incidental findings in asymptomatic patients. For more than 30 years, conventional imaging techniques for detection and assessment of congenital anomalies of the aorta have been chest X-ray, echocardiography and angiography. In recent times, considerable interest in congenital aortic diseases has been shown, due to technical progresses of noninvasive imaging modalities. Among them, magnetic resonance imaging (MRI) almost certainly offers the greatest advantages, especially in young patients in which a radiation exposure must be avoided as much as possible. MRI provides an excellent visualization of vascular structures with a wide field of view, well suited for evaluation of the thoracic aorta malformations. With the implementation of magnetic resonance angiography (MRA) it is also possible to depict any relationship with supra-aortic or mediastinal vessels. Phase contrast technique allows identification of the hemodynamic significance of the aortic alteration. Some technical considerations, which include fast spin-echo, gradient-echo and, especially, MRA techniques with phase-contrast and contrast enhanced methods, are discussed and applied in the evaluation of congenital thoracic aorta diseases.     

Contrast-enhanced MRA of the brain.

Most sequences for MR angiography (MRA) used today exploit the macroscopic motion of the blood to differentiate vessels from the stationary tissues. An alternative approach to inflow based MRA is contrast enhanced MRA, in which relaxation agents are used to selectively shorten the T1 of the blood below the T1 value of the stationary tissues. We have evaluated cerebral Gd enhanced MRA, comparing it with conventional angiography and noncontrast inflow based MRA. Contrast/enhanced MRAs were obtained at 1.0 T with a 3D FISP sequence with TR/TE/alpha: 35-40 ms, 7-11 ms/TE/25 degrees. Contrast enhancement was obtained by a biphasic injection of a double dose of Gd-DOTA (0.2 mmol/kg) during image acquisition. With the described technique the conspicuity of both cerebral arteries and veins is improved compared to nonenhanced inflow MRA.     

MR Angiography of the iliofemoral artery system

Summary During the last years, magnetic resonance angiography (MRA) has become a widely used modality for intracerebral and carotid artery imaging. Due to technical limitations, the clinical impact of MRA in the iliofemoral arteries has been rather poor. New developments in MRA like ECG-triggered sequences and the occurrence of contrast-enhanced MRA has overcome most of these limitations. Therefore, a major advance in clinical use of these diagnostic tools can be predicted. This paper discussed the advantages of ECG-gated 2D-Phase contrast, ECG-gated 2D-Time-of-Flight and contrast enhanced FLASH 3D angiography sequences from a clinical point of view. 2D-PC-MRA is a robust technique, which provides an overview of the iliofemoral artery system in less than 5 minutes. Limitations are the true 2D impression of the sequence and the partial venous overlay. 2D-TOF-MRA on the other hand is time consuming, however it enables 3D reconstruction and effective venous suppression can be applied. Contrast enhanced MRA as the third sequence discussed provides high resolution images in less than 30 sec. However contrast bolus timing might be a problem. In conclusion the authors suggest a combination of 2D-PC-MRA and additional 2D-TOF sequences at questionable vacular areas as the modality of choice, due to the fact, that MRA of the iliofemoral arteries ist mostly only one step of a complete lower limb examination. Contrast MRA might become the method of choice in the future however problems with multiple contrast injections and upper limits of contrast dose have to be solved.      

Acute cerebral ischemia: evaluation with dynamic contrast-enhanced MR imaging and MR angiography.

Dynamic contrast-enhanced T2-weighted magnetic resonance (MR) imaging and MR angiography (MRA) were used to evaluate cerebral blood volume and the intracranial arterial system in 34 patients within 48 hours after the onset of cerebral ischemia. In 24 of the patients, an abnormality identified on T2-weighted images corresponded to the acute clinical deficit. Intracranial MRA demonstrated occlusions or severe stenoses of major vessels supplying the area of infarction in 16 of these patients, and decreased blood volume correlated well with MRA abnormalities. Infarcts less than 2 cm in diameter were not reliably shown with MRA or blood volume studies. Correlation between lesions seen with MRA and decreased blood volume in acute infarcts was good, and both techniques demonstrated lesions early in the clinical course. By providing information about hemodynamics not available with conventional T1- or T2-weighted images, MRA and dynamic MR imaging could prove helpful in describing the pathophysiologic characteristics of stroke and in guiding early therapeutic intervention.     

MR angiography of carotid artery aneurysms in a porcine model at 3 tesla: Comparison of two different macrocyclic gadolinium chelates and of dynamic and conventional techniques

Purpose:

To evaluate the differences in image quality of two macrocyclic gadolinium‐based contrast agents, gadobutrol and gadoterate meglumine, using time‐resolved, contrast‐enhanced MR angiography (CE‐MRA) in a porcine carotid artery aneurysm model and to compare image quality between dynamic and conventional, single acquisition CE‐MRA.

Materials and Methods:

Bilateral carotid aneurysms were created surgically in this Institutional Animal Care and Use Committee approved study. Dynamic CE‐MRA studies optimized for high temporal resolution were performed at 3 Tesla. Scans using equivalently dosed (on a per mmol basis) gadobutrol and gadoterate meglumine were compared qualitatively and quantitatively in terms of contrast‐to‐noise ratio (CNR). Higher spatial resolution dynamic and conventional CE‐MRA were also compared.

Results:

N = 16 aneurysms were assessed. Qualitative evaluation of dynamic CE‐MRA scans demonstrated a preference for gadobutrol over gadoterate meglumine. Significantly higher aneurysm CNR was found with gadobutrol (133 ± 44) versus gadoterate meglumine, the latter at both equivalent and double injection rates (94 ± 35 and 102 ± 38). In a blinded assessment, conventional CE‐MRA was preferred qualitatively when compared with dynamic CE‐MRA. However, dynamic CE‐MRA was generally capable of providing diagnostic image quality.

Conclusion:

Gadobutrol is preferred to gadoterate meglumine for high temporal resolution dynamic CE‐MRA, a fact with important clinical implications for low dose CE‐MRA protocols in patients at risk for nephrogenic systemic fibrosis. Conventional high resolution CE‐MRA provides superior image quality when compared with dynamic CE‐MRA. J. Magn. Reson. Imaging 2012;36:1203–1212. © 2012 Wiley Periodicals, Inc.     

MR imaging of aortic coarctation

Aortic coarctation accounts for 5%–10% of all congenital heart diseases and represents 7% of critically ill infants with heart disease. Magnetic resonance (MR) imaging allows the study of this disease with several advantages in comparison with conventional angiography, transesophageal echocardiography, and computed tomography. The MR protocol applied at our institution for both diagnosis and follow-up after surgical or endovascular treatment consists of four steps: morphologic study, cine MR study, flow analysis, and MR angiography (MRA). The first three sequences are acquired during breath-hold and with electrocardiographic gating. Anatomy is well depicted with dark-blood half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. Cine true-fast imaging with steady-state precession (true-FISP) sequences show not only morphologic features but also blood-flow changes inside the aorta. Gradient-echo sequences for phase-velocity mapping allow flow analysis. Application of Bernoulli’s equation — here briefly presented and discussed — allows for calculation of the pressure gradient caused by the coarctation. MRA, acquired with a breath-hold three-dimensional T1-weighted gradient-echo sequence and intravenous administration of paramagnetic contrast material, allows for optimal depiction of the aortic lumen, with a panoramic view of the whole aorta, its main branches and possible collateral circulation.     

先天性心脏病伴单支冠状动脉的影像学诊断

目的：报道56例先天性心脏病伴先天性单支冠状动脉并评价其影像诊断方法。方法：全部56例先天性单支冠状动脉均作了心血管造影检查，有4例作了MR检查。48例经手术证实。结果：56例中，44例为单支左冠状动脉，其中3例右冠状动脉由左冠状动脉远端延续而成；另41例右冠状动脉由左冠状动脉近端发出。12例为单支右冠状动脉，其中1例左冠状动脉由右冠状动脉远端延续而成；另11例左冠状动脉由右冠状动脉近端发出。26例单支左冠状动脉和6例单支右冠状动脉有主要的冠状动脉血管横过右室流出道，并均经手术证实。结论：在先天性心脏病患者中单支冠状动脉并不得罕见，手术前正确的影像诊断对手术中不致误伤重要的冠状动脉有重要意义。     

症状性颅、颈部动脉狭窄在3.0T上的MRA与DSA比较研究

目的前瞻性分析3．0T应用SENSE技术的高分辨率对比增强容积扫描MRA（CEMRA）和3DTOFMRA在临床疑有颅、颈部动脉狭窄性病变患者中的应用价值。方法46例临床怀疑颅、颈部动脉狭窄的患者接受头颅MRI平扫、头颅3DTOFMRA和颈部CEMRA检查。动脉狭窄的程度与DSA检查结果进行相关性比较。结果MRA显示各段颅、颈部动脉狭窄的不同程度和DSA检查显著相关（Rs=0．97,P〈0．01）。以DSA结果为金标准,狭窄程度超过50％者MRA诊断灵敏度为100％,特异度为99．4％、准确率为99．4％。结论3．0T的3DTOFMRA和高分辨率CEMRA检查能可靠和有效地评价颅、颈部动脉狭窄性病变,可作为DSA术前必要的检查技术,或可替代传统DSA诊断性检查。     

Contrast-enhanced MR angiography of intracranial giant aneurysms

BACKGROUND AND PURPOSE: Intravoxel phase dispersion and flow saturation often prevent adequate depiction of intracranial giant aneurysms on 3D time-of-flight (3D-TOF) MR angiography (MRA). Additional diagnostic difficulties may arise from T1 contamination artifact of an associated blood clot. Our aim was to assess whether contrast-enhanced MRA could improve the evaluation of giant aneurysms and to compare two different types of contrast-enhanced MRA. METHODS: We studied 11 aneurysms in 10 patients (age range, 31-77 years) with giant aneurysms of the anterior (n = 9) and posterior (n = 2) cerebral circulation by comparing 3D-TOF, first-pass dynamic contrast-enhanced MRA, and steady-state contrast-enhanced 3D-TOF sequences. Additional comparison with digital subtraction angiography (DSA) was performed in eight aneurysms. RESULTS: In nine of 11 aneurysms, 3D-TOF did not adequately show the lumen and exiting vessels. Contrast-enhanced 3D-TOF and dynamic contrast-enhanced MRA showed the aneurysm sac and exiting vessels in all of these cases. Dynamic contrast-enhanced MRA showed a better intravascular contrast than did contrast-enhanced 3D-TOF, which led to better delineation of the aneurysms. T1 contamination artifact from intra- or extraluminal blood clot was evident on the 3D-TOF images in four cases. The artifact was less marked on the contrast-enhanced 3D-TOF image and was completely eliminated on the dynamic contrast-enhanced MRA image by subtraction of precontrast images. The diagnostic information provided by dynamic contrast-enhanced MRA was comparable to that provided by DSA. CONCLUSION: Precontrast 3D-TOF is inadequate for the assessment of giant cerebral aneurysms. Both contrast-enhanced 3D-TOF and dynamic contrast-enhanced MRA reliably show the aneurysm sac and connected vessels. Dynamic MRA provides a superior contrast between flow and background and eliminates T1 contamination artifact. It should therefore be considered as the MRA sequence of choice.     

Prospective evaluation of peripheral arterial occlusive disease by 2D MR subtraction angiography

The purpose of this study was to assess the diagnostic value of two-dimensional (2D) MR subtraction angiography of lower extremities in patients with symptomatic peripheral arterial occlusive disease with conventional angiography as the standard of reference. Twenty patients were prospectively included. 2D subtraction MR angiography (MRA) consisted of multisection gradient-recalled echo (GRE) acquisitions with the shortest TE available on our machine (4 msec), obtained in the coronal plane before and after intravenous bolus administration of gadolinium chelate. MR images were reconstructed after subtraction with a maximum-pixel-intensity-projection (MIP) algorithm. MRA was performed in all cases 1–4 days before diagnostic angiography. In a prospective blinded analysis, the number and location of significant (ie, >50%) stenoses and occlusions were evaluated for each vascular segment. Sensitivity and specificity were used to evaluate MRA data. Significant stenoses (38 of 46, 83%) and occlusions (66 of 67, 99%) seen at conventional angiography were identified with MRA. The sensitivity and specificity of MRA for determination of stenoses >50% or occlusions was 100% and 97%, respectively. The location and extent of stenoses and/or occlusions on MRA and angiograms were well correlated (kappa values, r = .73, P < .05). Contrast 2D MR subtraction angiography, by providing comparable information to that of conventional angiography, is well suited to evaluate the presence and severity of atherosclerotic lesions of the lower limbs.