肾动脉高分辨力三维增强磁共振血管成像术:透视触发和并行采集技术使用初探

目的:评估透视触发和并行采集技术用于肾动脉高分辨力三维增强磁共振血管成像术的可行性和对肾动脉的显影诊断效果。方法:90例临床诊断或怀疑肾动脉或腹主动脉病变的患者行高分辨力肾动脉三维增强磁共振血管成像(3D CE MRA)。使用透视触发软件启动肾动脉3D CE MRA扫描,扫描采用K空间中心填充法和加速因子为2的并行采集技术。分析图象质量和病变显示情况,并与其它检查结果对照。结果:肾动脉3D CE MRA显示了90例患者共810支动脉段(100%显示率),平均显示等级为3.88。3D CE MRA显示8例11支副肾动脉,显示等级均为4.0。肾动脉段级分支的显示率为73%(66/90例)。所有病例在动脉显示区静脉均未显影或显影很淡,平均等级为0.20。3D CE MRA发现639支动脉段正常;66支动脉段管壁不规则;55支动脉段轻度狭窄;37支动脉段严重狭窄;2支动脉段闭塞;11支动脉段动脉瘤形成。其中96支肾动脉存在狭窄,11支副肾动脉均正常。共有43例病例,肾动脉3D CE MRA与其它血管成像技术作了比较,3D CE MRA的检查结果与之完全符合。结论:透视触发并行采集肾动脉高分辨力3D CE MRA简单可行,成像时间短,空间分辨力高,能清楚显示肾动脉且无静脉污染。     

肾动脉动态增强磁共振血管造影

目的　对肾动脉动态增强磁共振血管造影的诊断价值作一初步评估。方法　选择 18例疑有肾动脉疾病患者进行DCEMRA检查。 2 0mlGd -DTPA造影剂经肘静脉快速注射后 ,采用FSPGR序列在一次屏气时间内对肾动脉进行 1～ 2个序列冠状位信号采集 ,将所获得的原始图像输入工作站进行后处理 ,最终获得肾动脉MIP和MPVR重建图像。结果　 12例肾动脉DCEMRA与动脉造影对照 ,DSA显示 12条肾动脉正常 ,DCEMRA显示 11条正常 ,1条轻度狭窄 ;DSA显示 5条轻度狭窄 ,DCEMRA显示其中 4条轻度狭窄 ,1条重度狭窄 ;DSA显示 5条重度狭窄和 3条闭塞与DCEMRA显示结果一致。结论　肾动脉DCEMRA检查与动脉造影比较具有很好的一致性 ,能够比较准确地评价肾动脉狭窄性病变 ,尤其对重度狭窄和闭塞准确性较高     

肾动脉纤维肌层发育不良的高分辨力三维增强MR血管成像

目的:评价高分辨力三维增强磁共振血管成像术(3D CE MRA)诊断肾动脉纤维肌层发育不良(FMD)的价值.方法:5例经临床和DSA造影确诊的肾动脉FMD患者行肾动脉高分辨力3D CE MRA检查,扫描同时使用透视触发和并行采集技术.分析所有患者的肾动脉和FMD显示情况,并与DSA对照.结果:肾动脉3D CE MRA清楚显示5例患者10支肾动脉主干及其近端段级分支,且静脉均未显影或显影很淡.5例FMD均为单侧肾动脉受累,2例表现为肾动脉主干和近端段级分支串珠状改变,3例表现为肾动脉中段局限性狭窄.3D CE MRA显示结果与DSA一致.结论:高分辨力肾动脉3D CE MRA能较好检出肾动脉主干和近端分支的FMD.     

自动移床并行采集高分辨率下肢动脉磁共振血管成像术

目的初步评估并行采集高分辨率下肢动脉磁共振血管成像术对下肢动脉的显影和诊断效果。资料与方法80例接受高分辨率下肢动脉三维增强磁共振血管成像（3DCEMRA）检查。3DCEMRA共分3段采集,通过自动移床分段扫描。扫描覆盖腹主动脉中下段到小腿动脉分支。将显示的动脉分为23段进行分析。首先根据血管和管壁显示清晰度给每段动脉的显示质量评分,其次对3段扫描区域中有无静脉早期显影评分,然后分析血管病变,将其分成：动脉管壁不规则（管腔狭窄〈10％）;轻度狭窄（〈50％）;严重狭窄（≥50％）;闭塞和动脉瘤形成。7例下肢动脉3DCEMRA的显示结果与其他检查结果做了对照。结果所有病例均顺利完成下肢动脉3DCEMRA检查。下肢动脉3DCEMRA显示了80例患者总共1840支动脉段（100％显示率）,平均显示等级为3．78。所有病例3个扫描段内静脉均未显影或显影很淡,不影响诊断,平均等级为0．25。本组结果显示了1458段动脉病变,包括608段动脉管壁不规则;498段动脉轻度狭窄;312段严重狭窄;38段闭塞;2段腹主动脉下段动脉瘤形成。69例下肢动脉闭塞症（PAOD）患者中发现有19例同时伴有肾动脉狭窄。3DCEMRA还能显示搭桥血管是否通畅。下肢动脉3DCEMRA的检查结果与其他血管成像技术完全符合。结论并行采集高分辨率下肢动脉3DCEMRA扫描范围大,成像时间短,空间分辨率高,能清楚显示下肢动脉及分支,它能在下肢动脉病变的诊断中起重要作用。     

透视触发并行采集高分辨率三维增强颈动脉磁共振血管成像术

目的评估透视触发和并行采集技术用于高分辨率三维增强颈动脉磁共振血管成像术(3DCEMRA)的可行性。方法80个临床诊断或怀疑颈动脉狭窄的病人接受3DCEMRA检查。使用透视触发软件触发启动颈动脉3DCEMRA扫描,同时采用K空间椭圆形中心填充法和加速因子为2的并行采集技术。对显示的各段动脉和有无静脉早期显影做分析。动脉狭窄分成动脉管壁不规则、轻度狭窄、严重狭窄和闭塞。颈动脉3DCEMRA的显示结果与其他检查结果做了对照。结果所有病例均顺利触发和完成颈动脉3DCEMRA检查。3DCEMRA显示了80例病人总共800支动脉段(100%显示率),所有病例在动脉显示区域内静脉均未显影或显影很淡,对诊断不构成影响。结果显示有680段动脉正常、41段动脉管壁不规则、24段动脉轻度狭窄、51段严重狭窄和4段闭塞。另外10段颈动脉狭窄处溃疡形成,12例患者除见颈动脉狭窄以外,还发现合并椎动脉和/或锁骨下动脉狭窄。36例病例,与其他血管成像技术作了比较,3DCEMRA的检查结果与之完全符合,未出现高估或低估血管狭窄程度。结论透视触发并行采集高分辨率3DCEMRA简单可行,成像时间短,空间分辨率高,能清楚显示颈动脉,它将在颈动脉狭窄的诊断中起重要作用。     

16排CT与DSA在肠系膜上动脉狭窄诊断中临床价值分析

目的探讨16排CT血管成像在肠系膜上动脉狭窄诊断中的应用价值。方法对我院因腹痛而拟诊断为肠系膜上动脉狭窄的21例患者进行16排CT血管成像和数字减影血管造影(DSA)检查。结果本文中的21例患者中DSA确诊为单纯肠系膜上动脉狭窄8例,单纯肠系膜上动脉夹层并管腔狭窄2例,主动脉夹层累及肠系膜上动脉引起管腔狭窄11例;21例患者共计检查了304条肠系膜上动脉主干及其Ⅰ级分支,其中CTA共计发现狭窄及闭塞血管124条,DSA发现狭窄及闭塞130条。经统计分析显示CTA诊断轻度狭窄的敏感度为86%,特异度为96%,阳性预测值为75%,阴性预测值为98%;CTA诊断中度狭窄的敏感度为82%,特异度为92%,阳性预测值为70%,阴性预测值为96%;CTA诊断重度狭窄及闭塞的敏感度为100%,特异度为96%,阳性预测值为89%,阴性预测值为100%。结论 16排CT血管成像能快速、准确地诊断肠系膜上动脉狭窄,值得临床推广使用。     

对亲体肾移植供肾者血管影像学诊断方法的评价

目的　对亲体肾移植供肾者血管的影像学诊断方法进行了评价。方法　 30例亲体肾移植供肾者中12例行MSCTA, 10例行肾动脉DSA, 4例行非增强MRA, 3例同时行MSCTA和DSA, 1例同时行DSA和非增强MRA。结果　30例供肾者显示肾动脉 68支,其中 1例左肾动脉早期分支。15例CTA检查中, 13例双肾单支动脉供血,其中 1例左肾动脉分支早,且为双肾盂双输尿管畸形; 1例右肾见 1支副肾动脉, 1例左肾见 1支副肾动脉。有 3例同时做了DSA检查,与CTA显示相似,为单支肾动脉。14例DSA检查, 8例双肾均为单支动脉, 4例一侧见副肾动脉,右侧 2例,左侧 2例。5例行非增强MRA检查, 3例双肾均为单支动脉, 1例左肾见 1支副肾动脉,而右侧 1支副肾动脉未能显示清楚,另 1例右侧肾 1支副肾动脉也未能显示清楚。结论　术前对亲体肾移植供体肾血管行MSCTA和DSA检查结果与手术所见相一致,较非增强MRA检查准确。而MSCTA以其快捷、方便、价廉及无创的优势可以取代DSA。     

3.0T高分辨率CE-MRA对颈部血管狭窄的诊断价值

目的探讨三维对比增强磁共振血管成像(3D CE-MRA)在颈部动脉血管狭窄诊断中的临床应用价值。方法对23例临床拟诊颈部动脉血管狭窄行数字减影血管造影(DSA)的患者行颈部3D CE-MRA。将两种方法检查结果进行相关性比较。结果 23例患者共230个节段血管,3D CE-MRA显示了227个节段,共诊断出74处(32.6%)狭窄,其中28处轻度狭窄,22处中度狭窄,20处重度狭窄,4处闭塞;DSA共显示了230个节段的血管,共诊断出69处(30.4%)血管狭窄,其中24处轻度狭窄,23处中度狭窄,19处重度狭窄,3处闭塞。与DSA相比,3DCE-MRA对颈部动脉轻度、中度、重度狭窄及动脉闭塞的显示敏感性均为100%,特异性分别为85.71%、90.91%、90%和75%,两种检查方法对颈部动脉狭窄程度的判断有良好的一致性(κ=0.921,P=0.000)。结论 3.0T 3DCE-MRA能够可靠的评价颈部动脉狭窄性病变,基本可以替代DSA检查。     

螺旋CT肾动脉成像与数字减影血管造影的对比分析

目的:客观评价螺旋CT肾动脉成像的临床应用价值.材料和方法:从本院螺旋CT肾动脉成像(CTRA)资料中选取31例曾做过DSA肾动脉造影(含动脉成形和支架放置术)者,CTRA和DSA图像分别先由两位医师独立观察.分析内容包括解剖变异、有无狭窄及进行狭窄程度分级.最后将结果进行对比分析.结果:CTRA发现狭窄血管33支,其中31支经DSA证实(2支假阳性).符合率为94%.清楚显示5支副肾动脉(经DSA证实).结论:CTRA是肾性高血压筛选的可靠方法并可取代DSA作为首选检查方法.     

多层CT血管成像在老年肾动脉狭窄相关疾病中的应用价值

目的:以数字减影血管造影(DSA)为参考标准,探讨多层CT血管成像(MDCTA)在无创诊断老年肾动脉狭窄相关性疾病中的应用价值。方法:对我院2012年1月至2014年3月经DSA证实的老年肾动脉狭窄相关疾病患者48例(男性27例,女性21例,年龄65~79岁,平均年龄71±5岁),于DSA术前行MDCTA前瞻性对照研究,观察MDCTA显示肾动脉狭窄的程度、位置、形态和数目等情况,并对不同病因所引起的肾动脉狭窄进行CT影像分析。结果:48例肾动脉狭窄相关疾病包括动脉粥样硬化性肾动脉狭窄42例、大动脉炎1例、先天性肾动脉发育不良1例、肾动脉纤维性肌性结构不良1例、肾动脉瘤1例、自发性肾动脉夹层1例和腹膜后肿瘤压迫1例。DSA证实狭窄肾动脉60支,均为主肾动脉,其中双侧26例,左侧5例,右侧3例。起始部狭窄48支,中部狭窄3支,全程狭窄9支。MDCTA显示血管狭窄65例,其敏感度为100%,特异度为87.8%,准确度为95.1%,阳性预测值为92.3%,阴性预测值为100%。狭窄程度MDCTA分级:0级36支,Ⅰ级20支,Ⅱ级29支,Ⅲ级11支,Ⅳ级5支;DSA分级:0级41支,Ⅰ级19支,Ⅱ级27支,Ⅲ级10支,Ⅳ级4支,两种检查方法评价肾动脉狭窄程度差异无统计学意义(Pearsonχ2=0.5805,P=0.965)。结论:MDCTA能清晰显示肾动脉狭窄的位置、数目和形态,并精确评价其狭窄程度和鉴别肾动脉狭窄相关性疾病的病因,可作为老年肾动脉相关性疾病无创性诊断的首选方法。     

High-spatial-resolution 3D balanced turbo field-echo technique for MR angiography of the renal arteries: initial experience

PURPOSE: To compare a multislab balanced turbo field-echo magnetic resonance (MR) angiographic technique, without the use of a contrast agent, with digital subtraction angiography (DSA) for imaging of the renal arteries. MATERIALS AND METHODS: Twenty-five randomly selected patients (eight women and 17 men; age range, 27-88 years; mean age, 72 years) suspected of having renal artery stenosis underwent both DSA and balanced turbo field-echo MR angiography. A consensus result was obtained among three radiologists in evaluation of main renal arteries on balanced turbo field-echo images and DSA images. Sensitivity, specificity, and negative and positive predictive values of the balanced turbo field-echo technique were calculated, and receiver operating characteristic analysis was performed for depiction of hemodynamically significant stenosis. Cohen kappa analysis was used to assess agreement between the two imaging methods in grading of stenoses and depiction of significant stenosis. Accessory renal arteries also were evaluated. RESULTS: Fifty main renal arteries and 11 accessory arteries were fully depicted with DSA. DSA depicted 11 stenotic lesions in the main renal arteries. In comparison, balanced turbo field-echo MR angiography enabled visualization of 46 of 50 main renal arteries to their first branching points and depicted 10 of 11 accessory arteries. Sensitivity, specificity, negative predictive value, and positive predictive value of this technique for depiction of significant stenosis were 100% (four of four), 98% (41 of 42), 100% (41 of 41), and 80% (four of five), respectively. The area under the receiver operating characteristic curve was 0.988. kappa was 0.782 for grading of stenoses and 0.877 for depiction of significant stenosis. CONCLUSION: Multislab balanced turbo field-echo imaging has potential as an MR angiography technique for depiction of normal and diseased renal arteries.     

Peripheral arterial disease. Contrast-enhanced 3D MR angiography of the lower leg and foot compared with conventional angiography

PURPOSE: To determine whether contrast-enhanced 3D MR angiography (CE MRA) could replace digital subtraction angiography (DSA) for the evaluation of atherosclerotic peripheral vascular disease of the lower leg and foot. MATERIAL AND METHODS: Thirty-five patients with symptoms of atherosclerotic disease of the leg were examined prospectively with CE MRA of the foot and the lower legs as well as with DSA from the aorta to the pedal arches. The MRA technique was focused on optimal imaging of the arteries of the foot. RESULTS: The agreement between CE MRA and DSA for grading of stenosis was moderate to good (weighted kappa-values 0.48-0.80). The sensitivity of CE MRA for detection of significant stenosis (> or = 50%) was 92% and the specificity was 64% with DSA as gold standard. CONCLUSION: CE MRA is a fairly accurate method for the demonstration of atherosclerotic disease below the knee including the pedal arches. It can replace DSA for the assessment of distal arteries in patients with impaired renal function. However, image quality and resolution still needs to be improved before CE MRA can become the method of choice in all patients.     

Renal arteriography using gadolinium enhanced 3D MR angiography--clinical experience with the technique, its limitations and pitfalls.

Gadolinium enhanced 3D MR angiography (MRA) is becoming a widely accepted technique for imaging the vascular system. We set out to evaluate its accuracy and reliability in visualization of renal arteries in the clinical setting. Gadolinium enhanced MRA was performed in 15 potential live renal donors and 26 patients suspected of having renal artery stenosis who were referred for digital subtraction angiography (DSA). MRA was performed on a 1.5 T MR scanner in a single breath hold. Images from each study were prospectively analysed for demonstration of number of main and accessory renal arteries and degree of renal artery stenosis in a double blind fashion. All the main and accessory arteries were visualized on MRA in the renal donor group, but in one case a branch was not identified owing to breathing artefact. In one case, an extrarenal vascular anomaly was not demonstrated on MRA. In the renal artery stenosis group, sensitivity, specificity and negative predictive values of 96%, 93% and 96% were obtained for clinically significant stenosis (>50%). Gadolinium enhanced MRA proved to be a useful technique in demonstration of renal arterial anatomy and grading of renal artery stenosis. However, we encountered some pitfalls and limitations of the technique during the process. It is important to be aware of these before accepting it as the sole technique in clinical practice.     

Accuracy of normal-dose contrast-enhanced MR angiography in assessing renal artery stenosis and accessory renal arteries

OBJECTIVE: The purpose of this study was to evaluate the accuracy of breath-hold contrast-enhanced MR angiography in the assessment of renal artery stenosis and accessory renal arteries using a standard dose of gadolinium. SUBJECTS AND METHODS: Thirty-eight patients suspected of having renal artery stenosis underwent MR angiography and intraarterial digital subtraction angiography, which was the method of reference. Three-dimensional gradient-echo MR subtraction angiography (TR/TE, 5.8/1.8 msec) was performed on a 1.5-T imager using a phased array body coil. Before imaging, a separate timing bolus sequence was used, administering 1.0 ml of contrast agent. Gadopentetate dimeglumine (15 ml) was injected using an MR power injector. Two observers, who were unaware of each other's interpretation and of MR findings, assessed digital subtraction angiography. Likewise, two other observers assessed MR angiography. RESULTS: Digital subtraction angiography depicted 75 main and 17 accessory renal arteries (n = 92). All main renal arteries and 13 accessory renal arteries were identified on MR angiography. Compared with digital subtraction angiography, MR imaging correctly classified 57 of 66 arteries without a hemodynamically significant stenosis (0-49%), 22 of 22 arteries as significantly stenotic (50-99%), and four of four occluded arteries; five stenoses were overestimated. There was one false-positive finding of an accessory renal artery on MR angiography that was identified retrospectively on digital subtraction angiography. Interobserver agreement was high. Sensitivity and specificity for grading significant stenosis were 100% and 85%, respectively. CONCLUSION: Contrast-enhanced MR angiography, using +/-0.1 mmol/kg of gadolinium, is an accurate method in the assessment of renal artery stenosis and accessory renal arteries.     

Non‐contrast renal artery MRA using an inflow inversion recovery steady state free precession technique (Inhance): Comparison with 3D contrast‐enhanced MRA

Purpose:

To assess the performance of a three‐dimensional (3D) non‐contrast respiratory‐triggered steady state free precession (SSFP) pulse sequence for detection of renal artery stenosis.

Materials and Methods:

A total of 64 patients who had non‐contrast MR angiography (NC MRA) and 3D contrast‐enhanced MRA (CE MRA) performed during the same exam and three patients who had NC MRA followed by conventional catheter angiography within one month of the MRI exam were included in this retrospective study. Two blinded readers evaluated NC MRA images for the presence of significant renal artery stenosis and also rated their diagnostic confidence and evaluated the images for artifact. A similar analysis was performed for CE MRA images by two additional blinded readers, and discrepancies were resolved by consensus reading.

Results:

The 67 patients had 168 main and accessory renal arteries, with significant (>50%) stenosis in 34 arteries on CE MRA or conventional angiography. The two NC MRA readers had sensitivity and specificity for detection of significant stenosis of 94%/82% and 82%/87% respectively on a per renal artery basis.

Conclusion:

There was good agreement between CE MRA and NC MRA for detection of significant renal artery stenosis. This technique should prove useful in evaluating patients with suspected renovascular hypertension who are unable to undergo CE MRA. J. Magn. Reson. Imaging 2010;31:1411–1418. © 2010 Wiley‐Liss, Inc.     

Contrast-enhanced 3D MRA with centric ordering in k space: A preliminary clinical experience in imaging the abdominal aorta and renal and peripheral arterial vasculature

The objective of this study was to determine the clinical utility of a contrast-enhanced, centric reordered, three-dimensional (3D) MR angiography (MRA) pulse sequence in imaging the abdominal aorta and renal and peripheral lower extremity arteries. Twenty-eight MRA studies were performed on 23 patients and four volunteers at 1.5 T using a 3D contrast-enhanced, centric reordered pulse sequence. In 20 patients, the abdominal aorta and renal arteries were imaged, and in seven patients, the lower extremity arteries were imaged. In 19 patients, a total of 51 renal vessels were evaluated (33 renal arteries using .1 mmol/kg of gadopentetate dimeglumine and 18 renal arteries using .2 mmol/kg of gadoteridol). A total of 70 peripheral arterial segments were assessed using .2 mmol/kg of gadoteridol. Correlation with conventional angiography was made for the following 14 cases: renal artery stenosis (four cases), abdominal aortic stenosis (one case), arteriovenous fistula in a transplant kidney (one case), renal arteriovenous malformation (one case), common iliac artery aneurysms (one case), and peripheral lower extremity (six cases). Of the 70 peripheral arterial segments evaluated, in 35, there was correlation with x-ray angiography. The mean percent of aortic signal enhancement was significantly higher in the .2 mmol/kg dose group (370.8 ± 190.3) than in the .1 mmol/kg dose group (184.5 ± 128.9) (P = .02). However, there was no apparent difference between the two doses for visualization of the renal and accessory renal arteries. There was concordance between the contrast-enhanced 3D MRA studies and conventional angiography in all cases of renal artery and peripheral arterial stenoses and occlusions, including visualization of reconstituted peripheral arterial segments. There was no evidence of spin dephasing effects at sites of stenoses on the 3D contrast-enhanced MRA studies. Contrast-enhanced, centric reordered, 3D MRA can rapidly image the abdominal aorta and renal and accessory renal arteries, as well as peripheral lower extremity arteries, with high resolution. Accurate depiction of the vascular lumen at sites of stenosis is made because of the lack of spin dephasing effects, even with hemody-namically significant stenoses. Additional larger clinical trials are required with this promising technique.     

Preoperative evaluation of living renal donors: value of contrast-enhanced 3D magnetic resonance angiography and comparison of three rendering algorithms

The aim of this study was to assess the value of contrast-enhanced three-dimensional MR angiography (CE 3D MRA) in the preoperative assessment of potential living renal donors, and to compare the accuracy for the depiction of the vascular anatomy using three different rendering algorithms. Twenty-three potential living renal donors were examined with CE 3D MRA (TE/TR=1.3 ms/3.7 ms, field of view 260–320×350 mm, 384–448×512 matrix, slab thickness 9.4 cm, 72 partitions, section thickness 1.3 mm, scan time 24 s, 0.1 mmol/kg body weight gadobenate dimeglumine). Magnetic resonance angiography data sets were processed with maximum intensity projection (MIP), volume rendering (VR), and shaded-surface display (SSD) algorithms. The image analysis was performed independently by three MR-experienced radiologists recording the number of renal arteries, the presence of early branching or vascular pathology. The combination of digital subtraction angiography (DSA) and intraoperative findings served as the gold standard for the image analysis. In total, 52 renal arteries were correspondingly observed in 23 patients at DSA and surgery. Other findings were 3 cases of early branching of the renal arteries, 4 cases of arterial stenosis and 1 case of bilateral fibromuscular dysplasia. With MRA source data all 52 renal arteries were correctly identified by all readers, compared with 51 (98.1%), 51–52 (98.1–100%) and 49–50 renal arteries (94.2–96.2%) with the MIP, VR and SSD projections, respectively. Similarly, the sensitivity, specificity and accuracy was highest with the MRA source data followed by MIP, VR and SSD. Time requirements were lowest for the MIP reconstructions and highest for the VR reconstructions. Contrast-enhanced 3D MRA is a reliable, non-invasive tool for the preoperative evaluation of potential living renal donors. Maximum intensity projection is favourable for the processing of 3D MRA data, as it has minimal time and computational requirements, while having similar or superior accuracy for the depiction of vessel anomalies or pathology compared with VR and SSD, respectively. Electronic Publication