Contrast-enhanced three-dimensional MR angiography of neck vessels: does dephasing effect alter diagnostic accuracy?

The aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading. Electronic Publication     

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。     

脑血管病变三维PC法MRA与动脉DSA的对照研究

目的 :通过与动脉 DSA结果的对照 ,研究三维 PC法 MRA对于检测各类脑血管病变的可信性。方法 :对临床或 MRI表现疑为或需排除脑血管病变的 5 9例兼作 MRA和 DSA检查 ,评价三维 PC法 MRA检测颅内各种血管病变的灵敏度、特异度、假阳性和假阴性率。结果 :MRA检出大于 5 mm的动脉瘤的灵敏度和特异度均达 10 0 %。但小于 5 mm者难以检出 ,使检出总灵敏度下降为 81.8%。 MRA检出 AVM的灵敏度为 92 .3%、特异度为 10 0 % ,畸形血管团及其主要供血动脉和引流静脉均可被 MRA显示。MRA检出颈内动脉 -海绵窦瘘的灵敏度和特异度均为 10 0 % ,表现十分典型。 MRA检出脑血管主干闭塞的灵敏度为 10 0 % ,特异度为 86 .70 % ,高度狭窄者可能过诊为闭塞。 MRA对于颅内占位病变引起的血管移位能全部显示 ,对于细小的肿瘤血管和肿瘤血供无法显示。结论 :MRA在脑血管病变的诊断上显示出很大的应用价值 ,对动静脉畸形、动静脉瘘、血管闭塞和血管移位的检测已有较高的灵敏度和特异度 ,对于较大动脉瘤的显示较好 ,对于小动脉瘤的检出率仍低 ,MRA对于肿瘤血管的检测基本无效。     

MR-angiography with contrast bolus vs digital angiography in peripheral arterial occlusive disease of the legs]

PURPOSE: Aim of our study was to compare MR Angiography and Digital Angiography in the diagnosis of peripheral vascular occlusive disease. MATERIAL AND METHODS: Forty-five patients underwent both MRA and DSA examination of the peripheral arterial district. We employed a 1.5 Tesla MRI unit using 3D FSPGR T1-w sequence on coronal scan plane (TR=5.2 ms; TE=1.5 ms; slice=1.5/3 mm; FOV=48 cm; matrix 384x512; TA=16/24 s), before and after automatic iv injection of Gd-DTPA BMA (0.15/0.3 mmol/kg) with a flow rate of 2 ml/s. We evaluated the vascular district from renal to medio-distal tibial arteries. The acquisition of this arterial district required a semi-automatic movement of the examination table. Qualitative and quantitative analyses were carried out according to MIP reconstructions. DSA evaluation, considered as the gold standard, was performed by trans-femoral access using a 4-5F catheter. RESULTS: The MRA examination detected 246 steno-occlusive lesions while 285 were identified with DSA. No statistically significant differences were found among the various degrees of stenotic lesions detected by the two METHODS. The MRA examination had specificity and sensitivity values of: 100% and 84,8% for the iliac axes; 98,9% and 94,3% for the femoral district; 100% and 84,9% for the popliteal district; 97% and 89% for tibial vessels. CONCLUSIONS: MRA showed a high diagnostic accuracy close to that of DSA. On the basis of our short experience we believe that MRA will be a useful method in the detection of various degrees of peripheral artery occlusive diseases reserving DSA for the therapeutical step.     

Actual role of unenhanced magnetic resonance angiography (mra tof 3d) in the study of stenosis and occlusion of extracranial carotid artery

PURPOSE: To evaluate the diagnostic accuracy, sensitivity and specificity of MRA (3D TOF) in comparison to contrast-enhanced MRA using DSA as the gold standard in the study of steno-occlusive disease of the internal carotid artery, in order to determine if this technique still has a diagnostic value. MATERIALS AND METHODS: Three radiologists blindly and independently evaluated either the unenhanced MRA, CE MRA, or DSA images of 23 consecutive patients, assessing the stenosis based on a NASCET five-class classification. RESULTS: The sensitivity, specificity, and diagnostic accuracy of CE MRA and unenhanced MRA were 100% and 100%, 100% and 95.5% and 100% and 93.2%, respectively. These differences were not statistically significant. CONCLUSIONS: Unenhanced MRA should be still considered a valid alternative for studying the extracranial section of the internal carotid arteries especially in patients who refuse or whose laboratory results exclude the use of contrast medium or in patients in whom continuous monitoring of a clinical condition is required but a repeated and/or frequent use of contrast medium is not possible.     

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。     

移床-血管示踪MR血管成像在下肢动脉疾病中的临床应用

目的研究移床-血管示踪MRA在下肢动脉疾病中的应用价值,探讨移床技术的优势。方法对36例临床疑有下肢动脉疾病的患者行移床-血管示踪三维动态增强MRA检查,其中急性下肢动脉闭塞症5例,检查后行急诊手术,慢性下肢动脉闭塞31例,其中10例行DSA检查。15例可评价病例以DSA或手术结果作为金标准进行效果评价。结果36例病人均满意地显示了完整的下肢动脉血管。将每条下肢分为14个血管节段观察,15例可评价病例共观察420段血管节段,显示可比动脉节段102段。与DSA或手术结果比较,两者诊断符合率为93.14%(95/102),MRA诊断的敏感度为100%,特异度为100%。5例急性下肢动脉闭塞症与手术结果比较,MRA对血管闭塞长度的评价与手术无统计学差异(t=2.251,P>0.05)。结论移床-血管示踪MRA与DSA或手术比较,具有很好的一致性,能全面、准确地评价下肢动脉病变,是一种可靠的、无创的、有应用价值的检查方法。     

Breath-hold gadolinium enhanced tree-dimensional MR angiography: personal experience in the thoracic-abdominal area

PURPOSE: To investigate different clinical applications of gadolinium-enhanced MR angiography (Gd MRA) using three-dimensional breath-hold GE sequences, without bolus time calculation, in patients with vascular diseases. MATERIAL AND METHODS: Forty-seven patients were examined (49 studies in all). Eleven of them had an abdominal aortic aneurysm, 6 surgical bypass, 7 renal artery stenosis, 3 aortoiliac Wallstent, 7 aortic stent-graft; 11 patients had a suspected condition in the thoracic aorta and pulmonary arteries, 1 had subclavian artery stenosis and 1 suspected axillary artery compression. All patients were submitted to breath-hold Gd MRA, after 30-40 mL Gd, with a 1.5 T magnet (Gyroscan ACS-NT, Philips, The Netherlands) and a standard body coil. The GE sequences were acquired with TR = 8.8, TE = 2.7, FA = 60 degrees, matrix = 163 x 512, with 28 seconds acquisition time. Digital subtraction angiography and intraoperative findings were the reference standards to evaluate the results. RESULTS: Thoracopulmonary district: metastatic compression of axillary vessels was found in 1 breast cancer patient; the true and the false lumens and the intimal flap were identified in 2 patients with chronic aortic dissection (Stanford A), and graft patency and complete resolution of the aortic dissection was seen in the patient operated on for acute aortic dissection (Stanford A). The thrombus, lumen, extent and diameter were studied in 2 patients with thoracic aortic aneurysms. Subclavian artery stenosis was demonstrated in 1 patient, which was treated with transluminal angioplasty and stenting. The other 6 patients had normal findings. Abdominal aortic aneurysms (AAA): as for disease extent, breath-hold Gd MRA had 100% sensitivity and specificity compared with surgical findings. Juxtarenal aneurysm extent, which had been missed at DSA, was detected in 1 patient and then confirmed at surgery. Stenosis: comparing DSA and MRA findings in the whole series of patients we had 97.4% agreement (155/159 arteries), that is 76.4% (13/17) arteries) considering only stenoses > 50%. Breath-hold Gd MRA sensitivity and specificity were 100 and 87.5%, respectively, in our 28 stenoses. Bypass, aortoiliac stent, vascular endograft: patency was demonstrated in all the 6 surgical bypass patients, and there was agreement with color Doppler findings in 5 of 6. Breath-hold Gd MRA seems to have no possible applications in the follow-up of percutaneously implanted iliac stents, but we had excellent findings about patency and position of nichel-titanium endografts used for AAA treatment. CONCLUSIONS: We optimized breath-hold 3D MRA without bolus transit time calculation and with high-dose Gd in different clinical vascular conditions. In our opinion, 3D GE sequences can replace DSA in selected cases, providing a fast, accurate and noninvasive examination.     

MR angiography of steno-occlusive lesions of intracranial arteries: a comparative study between turbo MRA and conventional MRA]

PURPOSE: To compare the quality and diagnostic accuracy of images of intracranial steno-occlusive lesions obtained by conventional MRA and turbo MRA reconstructed using the zero-filled interpolation technique in the slice-select direction. MATERIALS AND METHODS: Eighteen patients with suspected steno-occlusive lesions of the intracranial arteries were studied with two types of three-dimensional time-of-flight angiography and conventional digital subtraction angiography. In total, 45 steno-occlusive lesions were quantitatively measured using calipers and correlated with DSA stenosis. A phantom that simulated vessels with stenosis was also imaged using the two types of MRA under the same conditions as those employed in the clinical study. RESULTS: Compared with conventional MRA, turbo MRA reduced the jaggedness of vessels and offered appearances more similar to those of DSA in the antero-posterior and lateral views. The severity of stenosis was classified into five grades based on the percentage of occlusion: not significant (0-24%), mild (25-49%), moderate (50-74%), severe (75-99%), and occlusive (100%). Neither turbo MRA nor conventional MRA showed any discrepancy from DSA above grade-1 stenosis. CONCLUSION: The advantage of turbo MRA is its ability to reduce the jaggedness of vessels on conventional MRA, and to simplify the recognition of vessel contours without prolonging acquisition time. Turbo MRA and conventional MRA have equally high diagnostic accuracy for steno-occlusive lesions.     

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。     

螺旋CT血管造影在诊断脑动静脉畸形中的应用

目的探讨脑动静脉畸形(AVM)CT血管造影(CTA)的价值.材料与方法19例脑AVM病例行CTA检查,其中MRA、DSA检查各5例、8例.12例手术证实,7例保守治疗.CTA、MRA经工作站处理,获得三维血管图像;DSA通过股动脉插管技术,获得减影后血管图像.结果CTA能显示AVM的病变形态及准确部位,有效显示供养动脉、引流静脉及血管巢.但供养动脉显示不及MRA,引流静脉的显示较MRA为佳.结论CTA诊断脑AVM的图像质量、病变显示接近MRA、DSA,对制定治疗方案、指导手术和预后有重要意义.     

MR angiography of the intracranial vessels: technical aspects and clinical applications

Evaluation of the intracranial circulation provides valuable information in the diagnosis and prognosis of various intracranial abnormalities and may influence patient management. Technical advances in magnetic resonance angiography (MRA) have improved the accuracy of this technique in various clinical situations, such as aneurysms, arterial and venous steno-occlusive diseases, vascular malformations, inflammatory arterial diseases, preoperative assessment of the patency of dural sinuses, and congenital vascular abnormalities. In many centers, MRA has replaced conventional digital subtraction angiography in screening for intracranial vascular disease, because of its non-invasive and non-ionizing character. Several MRA techniques have been developed for the imaging of the intracranial vascular system, such as time-of-flight MRA (TOF MRA), phase-contrast MRA (PC MRA), and more recently contrast-enhanced MRA (CE MRA). In the evaluation of steno-occlusive disease, the three-dimensional (3D) TOF-MRA technique is recommended for arterial evaluation, and the 2D TOF or 2D PC-MRA technique for venous evaluation. For the evaluation of aneurysms and arteriovenous malformations (AVMs), we recommend the 3D CE-MRA technique, especially dynamic sequences in case of AVM. In this review, the technical aspects, limitations, and optimization of these MRA techniques will be discussed together with their indications in intracranial disease.     

Intracranial vascular stenosis and occlusion: comparison of 3D time-of-flight and 3D phase-contrast MR angiography

We compared the value of 3D time-of-flight (TOF) and phase-contrast (PC) MR angiography (MRA) for detection and grading of intracranial vascular steno-occlusive disease. Unenhanced 3D-TOF MRA and 3D-PC MRA (30–60 cm/s velocity encoding) were performed at the level of the circle of Willis in 18 patients, mean age 56 ± 10 years. Postprocessed images using a maximum-intensity projection reconstruction with multiple targetted projections were analysed. A total of 126 vessels was assessed by PC MRA and 143 by TOF MRA, with digital subtraction angiography (DSA) in 15 patients and/or transcranial Doppler sonography (TCD) in 18 as a standard. Two blinded readers reviewed the MRA, DSA and TCD examinations retrospectively. On DSA and/or TCD the two observers found 32 and 28 steno-occlusive lesions. 3D-TOF MRA was more sensitive than 3D-PC MRA (87 % and 86 % vs. 65 % and 60 %) and had a higher negative predictive value (96 % vs. 89 %). Correct grading of stenoses was achieved in 78 % by 3D-TOF and 65 % by 3D-PC MRA. Received: 24 September 1997 Accepted: 27 February 1998     

MR angiography in carotid stenosis: A comparison of three techniques

Purpose: To compare the accuracy of three different magnetic resonance angiography (MRA) techniques for studying steno-occlusive disease of carotid arteries. Methods: 64 patients were evaluated with three MRA techniques- three-dimensional (3D) time-of-flight (TOF), two-dimensional (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axial plane, the volume included the carotid bifurcation. Digital subtraction angiography (DSA) was considered the `gold standard'. The MRA images were reprojected with a maximum intensity pixel ray-tracing (MIP) algorithm. The three MRA techniques were blindly graded as normal, mildly stenotic (0–29%), moderately stenotic (30–49%), severely stenotic (70–99%), or occluded. Results: DSA provided 128 diagnostic judgments: 92 were negatives and 36 positives. 2D TOF was in agreement with angiography in 116 of 128 cases (90%), but overestimated the results in seven cases and underestimated in five cases. 3D TOF agreed with angiography in 125 of 128 cases (97%), with one overestimation and two under estimations. 3D PC was concordant in 116 of 128 cases (90%), overestimating in six cases, underestimating in six cases. The sensitivity, specificity and diagnostic accuracy for 2D TOF was, respectively 84%, 94%, and 92%, while for 3D TOF was 94%, 100%, and 98%, and for 3D PC 86%, 98%, and 95%. The comparison of the three different MRA techniques provided no statistically significant difference (Friedman test P<0.05). Conclusion: The high degree of diagnostic accuracy of MRA found in the study of the steno-occlusive disease of the carotid arteries confirms the high degree of reliability of this methodology carried out with the 3D TOF technique, compared to 2D TOF and 3D PC.     

时间分辨回波分享MRA和并行采集技术的临床应用

目的:评估时间分辨回波分享磁共振血管成像(TREAT MRA)和并行采集技术在血管性病变中的显示效果和临床应用价值。方法:25个临床诊断或怀疑血管性病变患者行TREAT MRA检查,采用3D FLASH序列,用加速因子为2的并行采集技术和回波分享技术填充K空间,采集1帧3D图像用时2~3 s,共12帧动态显示靶血管解剖结构。分析全部病例的图像质量和病变显示情况,并与其它检查作对照。结果:所有病例均顺利完成TREAT MRA检查;TREATMRA动态显示了动静脉充盈情况,至少有1~3帧动脉显示时无静脉污染;所有病例动脉结构显示清楚,包括动脉主干和肾、肺、手足动脉远端分支。TREAT MRA发现2例颈动脉和1例肾动脉狭窄,2例主动脉夹层和破口,前臂血管瘤,足部动静脉瘘和肺动静脉瘘各1例,病变显示清楚,10例行TREAT MRA的病例与其它检查技术结果比较,均与之完全符合。结论:TREAT MRA结合并行采集能以高时间分辨力清楚显示血管结构,效果类似于DSA。     

肾动脉狭窄的三维增强磁共振血管成像诊断

目的:评价高分辨力三维增强磁共振血管成像术(3DCEMRA)对肾动脉狭窄的显示准确性。方法:对30例临床诊断或怀疑肾动脉狭窄患者进行高分辨力肾动脉3DCEMRA检查,分析所有患者的肾动脉和副肾动脉显示质量和病变显示情况,并与DSA做对照。结果:3DCEMRA显示了30例患者总共59支肾动脉主干(1例为单支移植肾动脉),显示率为100%。3DCEMRA显示4支副肾动脉,显示率100%。肾动脉段级分支的显示率为49%。所有病例在动脉显示区域内静脉均未显影或显影淡,对诊断不构成影响。DSA共显示59支肾动脉主干和4支副肾动脉(以63支计算),59支主干中2支闭塞,8支重度狭窄,11支中度狭窄,10支轻度狭窄,28支肾动脉主干和4支副肾动脉都正常。3DCEMRA除把2支轻度狭窄估为中度狭窄,1支中度狭窄估为重度狭窄外,其它结果都同DSA一致,故3DCEMRA显示肾动脉主干和副肾动脉狭窄程度超过50%的有血液动力学意义的明显狭窄的敏感性和特异性分别为100%和95%,阳性预测值为91%,阴性预测值为100%。结论:高分辨力肾动脉3DCEMRA能准确检出肾动脉主干和副肾动脉狭窄,并能较好判断其狭窄程度。     

Follow-up of patients with previous treatment for coarctation of the thoracic aorta: comparison between contrast-enhanced MR angiography and fast spin-echo MR imaging

Regular follow-up is required in patients with previous intervention for coarctation of the aorta to detect recoarctation or aneurysm formation. In this study we describe the findings encountered on routine follow-up exams and we compare the use of contrast-enhanced 3D MR angiography (CE MRA) with fast spin-echo MRI (FSE) to study the thoracic aorta after previous intervention. In 51 consecutive patients previously treated for aortic coarctation, 74 MR studies of the thoracic aorta were performed during a 2-year period using CE MRA and FSE MRI. The thoracic aorta was evaluated for abnormalities of course, caliber, shape, and pathology of side branches. The CE MRA and FSE MRI studies were evaluated side by side by consensus of two reviewers evaluating which MR technique depicted the abnormalities of the thoracic aorta the best. Of 74 exams, six clinically important abnormalities were found: four aneurysms and two restenoses. Two small pseudoaneurysms were missed on the FSE studies. Contrast-enhanced MRA was judged to visualize aortic abnormalities better than FSE (47 of 74 MR studies) especially for the transverse aortic arch, coarctation site, left subclavian artery, and aortic arch configuration. For the ascending aorta and distal descending aorta, CE MRA and FSE performed equally well. Aortic diameters measured at four levels in the first 18 MRI studies showed no significant differences in diameter when measured by FSE or CE MRA (p = not significant). Clinically important abnormalities, such as aneurysm formation and restenosis, can be present years after treatment for aortic coarctation. In the regular follow-up of these patients, CE MRA may provide additional diagnostic information compared with FSE and should be included as part of the routine exam. Received: 3 April 2000; Revised: 5 July 2000; Accepted: 7 July 2000     

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.     

Magnetic resonance angiography in suspected cerebral vasculitis

The purpose of this study was to determine the technical capacity and diagnostic accuracy of 3D time-of-flight magnetic resonance angiography (MRA) in suspected cerebral vasculitis in a retrospective analysis of MRA and digital subtraction angiography (DSA) in 14 young patients with clinical and/or radiological suspicion of cerebral vasculitis. A total of nine arteries were evaluated in each patient. Consensus review of DSA by three observers was the reference standard. The sensitivity for detecting a stenosis varied from 62 to 79% for MRA and from 76 to 94% for DSA, depending on the observer. The specificity for detecting a stenosis varied from 83 to 87% for MRA and from 83 to 97% for DSA. Using the criterion more than two stenoses in at least two separate vascular distributions to consider the examination as being true positive, the false-positive rates for MRA and DSA were comparable. MRA plays a role as the first angiographical examination in the diagnostic work-up of suspected cerebral vasculitis. When more than two stenoses in at least two separate vascular distributions are depicted on MRA, DSA is not expected to add a significant diagnostic contribution in a patient with suspected cerebral vasculitis. DSA remains necessary when MRA is normal or when less than three stenoses are seen.     

3D-T0F MRA对颅内动脉瘤GDC治疗随访的预期评估

目的：评价磁共振血管成像(MRA)在随访43例病人的45个颅内动脉瘤GDC栓塞后的价值。材料和方法：以数字减影血管造影(DSA)作为诊断的金标准，回顾研究43例病人的45个颅内动脉瘤(前循环34个，后循环11个)MRA检查。所有的病人在GDC栓塞治疗后9个月之内的同一周行DSA和MRA检查，这期间不作处理。分析弹簧圈内残余血流、载瘤动脉和邻近动脉血流，MRA以最大强度投影(MIP)重建和源图像为基础。结果：所有病例中，MRA能提供良好的信息。对于动脉瘤的分析，MRA的敏感性、特征性、阳性预测价值、阴性预测价值，诊断弹簧圈内残余血流分别为87．5％、100％、100％、97％，诊断瘤颈的残余血流分别为90％、100％、100％、97％。对于动脉通畅性分析，MRA的敏感性和阴性预测价值，载瘤动脉分别是90．5％和100％，邻近动脉分别是85．7％和100％。结论：在随访GDC栓塞的动脉瘤中，MRA可以作为一个筛选手段，提高检查效率，减少病人的随访风险。