NC100150-enhanced 3D-SPGR MR angiography of the common carotid artery in a pig vascular stenosis model. Quantification of stenosis and dose optimization.

PURPOSE: NC100150 is a new type of ultra-small iron oxide (USPIO) blood pool agent. The aim of this study was to compare NC100150-enhanced MR angiography (MRA) to time-of-flight (TOF) MRA, phase-contrast (PC) MRA, and digital subtraction angiography (DSA) in experimental stenoses in pigs, and furthermore to determine the optimal dose of the contrast agent. MATERIAL AND METHODS: An experimental stenosis of the right and left common carotid artery (CCA) was applied surgically in 6 Yorkshire pigs. DSA was performed as the gold standard, followed by 3D-TOF, 3D-PC, and NC100150-enhanced MRA. RESULTS: Eleven stenoses of the CCA were successfully applied. The degree of the stenosis, determined by NC100150-enhanced MRA, did not differ significantly from DSA, whereas TOF and PC MRA underestimated it. The image quality of the NC100150-enhanced MRA was superior to both TOF and PC MRA. The optimal dose of NC100150 was 5-6 mg Fe/kg, since higher doses did not further increase signal-to-noise ratio or contrast-to-noise ratio. There was a linear relationship between blood relaxation rate and contrast dose. CONCLUSION: NC100150-enhanced MRA has the potential for quantification of carotid stenoses and provides an alternative to DSA. The optimal dose of NC100150 was 5-6 mg Fe/kg.     

连续三维时飞法磁共振血管成像对脑动脉的显示能力评价

目的评价连续3D-TOF和高速度编码的三维相位对比法(Venc3D-PC)MRA对脑动脉的显示能力。方法前瞻性选取脑MRI表现正常且连续3D-TOF及高Venc3D-PC磁共振脑动脉成像表现正常者15例,用以评价2种MRA技术显示脑动脉的差异。回顾性选取进行脑动脉MRA及DSA2种检查者43例,以DSA为标准,取其中38侧表现正常者用以评价MRA显示脑动脉的能力。结果3D-TOF与高Venc3D-PC技术显示ACA、MCA或PCA的最大级数均无显著统计学差异,但前者的图像质量优于后者。MRA显示ACA、MCA和PCA的分支级数与DSA均有显著差异性。MRA对ACA和MCA的显示能力均较DSA减少1个级别,对PCA的显示能力差别不大。结论连续3D-TOFMRA对脑动脉的显示能力小于DSA,但已能满足大多数脑血管疾病的临床应用。     

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.     

Three-dimensional time-of-flight MR angiography for evaluation of intracranial aneurysms after endosaccular packing with Guglielmi detachable coils: comparison with 3D digital subtraction angiography

The sensitivities and specificities of three-dimensional time-of-flight MR angiography (3D-TOF MRA) and 3D digital subtraction angiography (3D-DSA) were compared for evaluation of cerebral aneurysms after endosaccular packing with Guglielmi detachable coils (GDCs). Thirty-three patients with 33 aneurysms were included in this prospective study. 3D-TOF MRA and 3D-DSA were performed in the same week on all patients. Maximal intensity projection (MIP) and 3D reconstructed MRA images were compared with 3D-DSA images. The diameters of residual/recurrent aneurysms detected on 3D-DSA were calculated on a workstation. In 3 (9%) of 33 aneurysms, 3D-TOF MRA did not provide reliable information due to significant susceptibility artifacts on MRA. The sensitivity and specificity rates of MRA were 72.7 and 90.9%, respectively, for the diagnosis of residual/recurrent aneurysm. The diameters of residual/recurrent aneurysms that could not be detected by MRA were significantly smaller than those of detected aneurysms (mean 1.1 vs mean 2.3 mm). In one aneurysm of the anterior communicating artery (ACoA), the relationship between the residual aneurysm and the ACoA was more evident on MRA than DSA images. MRA can detect the recurrent/residual lumen of aneurysms treated with GDCs of up to at least 1.8 mm in diameter. 3D-TOF MRA is useful for follow-up of intracranial aneurysms treated with GDCs, and could partly replace DSA.     

MR angiography of dural arteriovenous fistulas: diagnosis and follow-up after treatment using a time-resolved 3D contrast-enhanced technique

BACKGROUND AND PURPOSE: Digital subtraction angiography (DSA) is the method of reference for imaging of dural arteriovenous fistula (DAVF). The goal of this study was to analyze the value of different MR images including 3D contrast-enhanced MR angiography (MRA) with a high temporal resolution in diagnostic and follow-up imaging of DAVFs. MATERIALS AND METHODS: A total of 18 MR/MRA examinations from 14 patients with untreated (n=9) and/or treated (n=9) DAVFs were evaluated. Two observers assessed all MR and MRA investigations for signs indicating the presence of a DAVF, for fistula characteristics such as fistula grading, location of fistulous point, and fistula obliteration after treatment. All results were compared with DSA findings. RESULTS: On time-resolved 3D contrast-enhanced (TR 3D) MRA, the side and presence of all patent fistulas (n=13) were correctly indicated, and no false-positive findings were observed in occluded DAVFs (n=5). Grading of fistulas with this imaging technique was correct in 77% and 85% of patent fistulas for both readers, respectively. On T2-weighted images, signs indicative of a DAVF were encountered only in fistulas with cortical venous reflux (56%), whereas on 3D time-of-flight (TOF) MRA, most fistulas (88%) were correctly detected. In complete fistula occlusion, false-positive findings were encountered on both T2-weighted images and on TOF MRA images. CONCLUSION: In this study, TR 3D MRA proved reliable in detecting DAVFs and suitable for follow-up imaging. The technique allowed--within limitations--to grade DAVFs. Although 3D TOF MRA can depict signs of DAVFs, its value for follow-up imaging is limited.     

2D time-of-flight MR angiography using concatenated saturation bands for determining direction of flow in the intracranial vessels

We prospectively studied 15 patients to assess 2D time-of-flight (TOF) magnetic resonance angiography (MRA) with concatenated saturation bands for determining the direction of intracranial blood flow. This MRA sequence was compared to T2-weighted spin-echo MRI, 3D-TOF MRA, and intra-arterial angiography (IAA) as regards demonstration of vessels and determination of the direction of flow in the circle of Willis and its branches. The 2D-TOF MRA sequence demonstrated flow in 98.5 % vessel segments identified on IAA, 3D-TOF demonstrating 92 % and spin-echo images 77 %. The direction of flow shown on the 2D-TOF sequence was correct in 94 % when compared to conventional angiography, the remaining six segments not demonstrating flow. In ten patients, the flow abnormalities demonstrated by this MRA technique provided clinical information similar to that of conventional angiography in nine, but it was incomplete in three, and misleading in one. Slow retrograde flow in ophthalmic artery collaterals and differentiation of arteries and veins presented some problems. 2D-TOF MRA with concatenated saturation bands provides flow direction information using widely available, easily applicable TOF techniques, and can be a useful adjunct to MRI and MRA if information on flow direction is needed. Received: 18 October 1995 Accepted: 16 August 1996     

Postoperative assessment of extracranial-intracranial bypass by time-resolved 3D contrast-enhanced MR angiography using parallel imaging

PURPOSE: Our goals were to assess image quality of time-resolved contrast-enhanced MR angiography (CE MRA), by using 3D data acquisition along with a parallel imaging technique that can improve temporal resolution and to compare this technique with 3D-time-of-flight (TOF) MRA in the postoperative assessment of extracranial (EC)-intracranial (IC) bypass surgery. METHODS: On a 1.5T imaging system, we performed CE MRA by using a 3D fast field-echo sequence in combination with a parallel imaging technique, to obtain images in the coronal plane centered at the postoperative site. Our patient group comprised 17 patients, including 13 after superficial temporal artery-middle cerebral artery (MCA) anastomosis, 3 after external carotid artery-MCA anastomosis, and one after extracranial vertebral artery-posterior cerebral artery anastomosis. Visualization of the anastomosis and the distal flow on the CE-MRA images was assessed comparatively with that on 3D-TOF MR angiograms obtained at the same time. In 6 patients, we also compared the efficiency of visualization on CE-MRA images with that on conventional angiograms. RESULTS: A temporal resolution of 0.8 s/frame could be achieved with the technique employed. The bypass was better demonstrated postoperatively on CE-MRA images than on 3D-TOF MR angiograms in 13 patients (76%), whereas the 2 methods were equivalent in 4 patients (24%). Good correspondence of results was observed in the 6 patients for whom CE MRA and conventional digital subtraction angiography (DSA) images were compared. CONCLUSION: CE MRA by using the parallel imaging technique can increase image acquisition speed with sufficient image quality. This technique is at least equivalent to 3D-TOF MRA to evaluate the postoperative status of EC-IC bypass.     

Intracranial vascular stenosis and occlusive disease: evaluation with CT angiography, MR angiography, and digital subtraction angiography

BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) provides excellent visualization of the intracranial vasculature, it has several limitations. Our purpose was to evaluate the ability of helical CT angiography (CTA) to help detect and quantify intracranial stenosis and occlusion compared with DSA and MR angiography (MRA). METHODS: Twenty-eight patients underwent CTA, DSA, and 3D time-of-flight (TOF) MRA for suspected cerebrovascular lesions. All three studies were performed within a 30-day period. Two readers blinded to prior estimated or calculated stenoses, patient history and clinical information examined 672 vessel segments. Lesions were categorized as normal (0-9%), mild (10-29%), moderate (30-69%), severe (70-99%), or occluded (no flow detected). DSA was the reference standard. Unblinded consensus readings were obtained for all discrepancies. RESULTS: A total of 115 diseased vessel segments were identified. After consensus interpretation, CTA revealed higher sensitivity than that of MRA for intracranial stenosis (98% versus 70%, P < .001) and occlusion (100% versus 87%, P = .02). CTA had a higher positive predictive value than that of MRA for both stenosis (93% versus 65%, P < .001) and occlusion (100% versus 59%, P < .001). CTA had a high interoperator reliability. In 6 of 28 patients (21%), all 6 with low-flow states in the posterior circulation, CTA was superior to DSA in detection of vessel patency. CONCLUSION: CTA has a higher sensitivity and positive predictive value than MRA and is recommended over TOF MRA for detection of intracranial stenosis and occlusion. CTA has a high interoperator reliability. CTA is superior to DSA in the evaluation of posterior circulation steno-occlusive disease when slow flow is present. CTA results had a significant effect on patient clinical management.     

3D-SPACE序列结合3D-TOF MR血管成像在颅内动脉瘤支架辅助弹簧圈栓塞术后随访中的应用

目的探讨三维T1加权序列可变反转角度快速自旋回波序列(3D T1-SPACE)结合三维时间飞跃法MR血管成像(3D-TOF MRA)在颅内动脉瘤支架辅助弹簧圈栓塞术后患者随访中的应用价值。方法前瞻性收集2017年12月至2018年10月河南省人民医院收治的25例因颅内动脉瘤接受支架辅助弹簧圈栓塞术的患者,均为宽颈动脉瘤。术后6~10个月所有患者均行3D-TOF MRA、3D T1-SPACE序列MR扫描和DSA检查。分别使用3D-TOF MRA和DSA以Raymond分级法评价瘤腔栓塞情况,使用3D-TOF MRA和3D T1-SPACE序列以4分法评价载瘤动脉支架内管腔显示情况。采用配对设计的Wilcoxon秩和检验比较动脉瘤栓塞程度分级和支架内管腔显示情况。以DSA为金标准,计算3D-TOF MRA评估动脉瘤残留的特异度及准确率。结果术后6~10个月随访,对于动脉瘤闭塞情况,DSA造影显示Raymond 1级23例,2级1例,3级1例;3D-TOF MRA 1级21例,2级3例,3级1例;差异无统计学意义(Z=-0.557,P=0.577),其中有4例患者两种评估方法结果不一致。对于载瘤动脉支架内管腔情况的显示,3D-TOF MRA评分3分14例,2分8例,1分3例;3D T1-SPACE序列25例均为4分,3D T1-SPACE优于3D-TOF MRA(Z=-4.484,P<0.001)。以DSA为金标准,3D-TOF MRA结合原图像评估动脉瘤栓塞情况的特异度为86.9%(20/23),准确率为84.0%(21/25)。结论3.0 T MR 3D T1-SPACE序列可清晰显示支架内管腔,能准确判断支架内血管的通畅情况,3D-TOF MRA可充分评估动脉瘤瘤腔有无残留。将上述两种MRI血管成像技术相结合,可用于动脉瘤支架辅助栓塞术后的随访。     

Follow-up of coiled intracranial aneurysms: comparison of 3D time-of-flight and contrast-enhanced magnetic resonance angiography at 3T in a large, prospective series

Objectives

To compare 3D-TOF magnetic resonance angiography (MRA) and contrast-enhanced MRA (CE-MRA) sequences at 3T in the follow-up of coiled aneurysms with digital subtracted angiography (DSA) as the gold standard.

Methods

DSA, 3D-TOF and CE-MRA were performed in a prospective series of 126 aneurysms in 96 patients (57 female, 39 male; age: 25–75 years, mean: 51.3?±?11.3 years). The quality of aneurysm occlusion was assessed independently and anonymously by a core laboratory.

Results

Using DSA (gold standard technique), total occlusion was depicted in 57 aneurysms (45.2%), neck remnant in 34 aneurysms (27.0%) and aneurysm remnant in 35 aneurysms (27.8%). Sensitivity, specificity, positive predictive value and negative predictive value were very similar with 3D-TOF and CE-MRA. Visibility of coils was much better with 3D-TOF (95.2%) than with CE-MRA (23.0%) (P?P?=?0.012).

Conclusions

In this large prospective series of patients with coiled aneurysms, at 3T 3D-TOF MRA was equivalent to CE-MRA for the evaluation of aneurysm occlusion, but coil visibility was superior at 3D-TOF. Thus the use of 3D-TOF at 3T is recommended for the follow-up of coiled intracranial aneurysms.

Key Points

? Different Magnetic Resonance (MR) imaging techniques are used to evaluate intracranial aneurysms. ? At 3T MR, 3D-TOF and CE-MRA appear equivalent for evaluating coiled aneurysms.. ? Coils are better visualised on 3D-TOF than on CE-MRA. ? Combined analysis of 3D-TOF and CE-MRA does not seem helpful. ? At 3T, 3D-TOF techniques are recommended for monitoring patients with coiled aneurysms.     

3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值

目的：探讨3D TRICKS MRA对颈动脉粥样硬化狭窄的诊断价值。方法：对43例临床疑诊颈动脉粥样硬化狭窄的患者行2D TOF MRA和3D TRICKS MRA检查,其中31例同期行DSA检查,以颈总动脉法（CC法）计算狭窄率。结果：颈动脉闭塞2支,重度狭窄10支,中度狭窄31支,轻度狭窄25支,正常18支。2D TOF MRA、3D TRICKS MRA与DSA对照,显示狭窄部位均与DSA所示相符。2D TOF MRA高估狭窄程度6支,3D TRICKS MRA高估狭窄程度1支。以DSA为标准,2D TOF MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为91.6%,85.7%,90.3%（K=0.737）;3D TRICKS MRA诊断颈动脉狭窄的敏感度、特异度、诊断符合率分别为97.9%,100%,98.4%（K=0.955）。两种方法对诊断颈动脉狭窄的敏感度、特异度和诊断符合率差异均具有统计学意义（P〈0.05）。结论：3D TRICKS MRA与DSA对评估颈动脉粥样硬化狭窄具有极好的一致性（K=0.955）,明显优于2D TOF MRA（K=0.737,P〈0.05）,是对颈动脉粥样硬化狭窄筛查、术前评估、术后随访的最佳检查方法,能基本替代DSA检查。     

颅脑磁共振血流成像：不同成像方法的临床应用

本文旨在研究磁共振血流成像（ＭＲＡ）在颅脑疾病的应用价值及最佳方法选择。６０例脑血管疾病ＭＲＡ检查中，４８例用两种以上ＭＲＡ方法检查，２４例做了ＤＳＡ对照。研究结果显示：无出血时，脑动脉狭窄、动脉瘤应首选ＭＯＴＳＡ；ＡＶＭ首选多流速编码的２Ｄ－ＰＣ，并联用３Ｄ－ＴＯＦ或３Ｄ－ＰＣ；有明显出血时，各种病变均应首选３Ｄ－ＰＣ。     

Three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) and contrast-enhanced MRA of intracranial aneurysms treated with platinum coils

Background: Contrast-enhanced magnetic resonance angiography (CE-MRA) is less prone to flow-related signal intensity loss than three-dimensional time-of-flight (3D TOF) MRA and may therefore be more sensitive for detection of residual patency in platinum coil-treated intracranial aneurysms.

Purpose: To compare MRA and CE-MRA in the follow-up of intracranial aneurysms treated with platinum coils.

Material and Methods: CE-MRA and 3D TOF MRA (pre- and postcontrast injection) of the intracranial vasculature was performed at 1.5T in 38 patients (47 aneurysms) referred for DSA in the follow-up of coiled intracranial aneurysms.

Results: DSA showed aneurysm patency in 22/47 investigations. Patent aneurysm components were observed with CE-MRA in 18/22 cases, and with 3D TOF MRA in 21/22 cases. There was no significant difference in patent aneurysm component size between CE-MRA and 3D TOF MRA. In addition, CE-MRA showed six, 3D TOF MRA before contrast injection showed seven, and 3D TOF MRA after contrast injection showed eight cases with patent aneurysm components not observed on DSA.

Conclusion: 3D TOF MRA was highly sensitive for detection of patent aneurysm components, and at least as sensitive as CE-MRA. Residual aneurysm patency seems to be better visualized with MRA than with DSA in some cases.     

The role of contrast-enhanced MR angiography in the assessment of recently ruptured intracranial aneurysms: a comparative study

We evaluated contrast-enhanced MR angiography (MRA) for the identification of recently ruptured cerebral aneurysms. We studied 23 aneurysms in 18 patients (age range 34–72 years) with aneurysms of the anterior (n=17) and posterior (n=6) circulation by comparing 3D time-of-flight (TOF), contrast-enhanced MRA and digital subtraction angiography (DSA). In four of 23 aneurysms, 3D-TOF did not show the lesion. Contrast-enhanced MRA successfully depicted all aneurysms except one. T1 contamination artefacts from subarachnoid or intraparenchymal haemorrhages were evident on the 3D-TOF images in six cases. The artefacts were completely eliminated on the contrast-enhanced MRA images by subtraction of the pre-contrast images. The diagnostic information in patients with subarachnoid haemorrhages (SAHs) provided by contrast-enhanced MRA was comparable to that provided by DSA.The contents of this article were presented as a poster entitled Contrast-enhanced MR angiography of intracranial aneurysms at the 28th annual meeting of the European Society of Neuroradiology (ESNR), Istanbul, Turkey, 11–14 September 2003     

Diagnostic accuracy of 3D time-of-flight MR angiography compared with digital subtraction angiography for follow-up of coiled intracranial aneurysms: influence of aneurysm size

BACKGROUND AND PURPOSE: 3D time-of-flight MR angiography (3D TOF MRA) may be used as noninvasive alternative to digital subtraction angiography (DSA) for the follow-up of patients with intracranial aneurysms treated with Guglielmi detachable coils (GDCs). We aimed to determine the influence of aneurysm size and location on diagnostic accuracy of 3D TOF MRA for follow-up of intracranial aneurysms treated with GDCs. MATERIALS AND METHODS: Two hundred and one 3D TOF MRAs in 127 consecutive patients with 136 aneurysms were compared with DSA as standard of reference. Sensitivity and specificity of 3D TOF MRA for detection of residual or reperfusion of the aneurysms was calculated with regard to aneurysm size and location. RESULTS: Overall sensitivity and specificity of MRA was 88.5% and 92.9%, respectively. Sensitivity was lower for aneurysms 相似文献   

3D-TOF MRA对颅内血管性病变的诊断价值

目的：探讨３Ｄ－ＴＯＦ ＭＲＡ对颅内血管性病变的应用价值。材料与方法：回顾分析了６２例ＭＲＡ检查，全部采用３Ｄ－ＴＯＦ技术，矩阵１６０／１９０，ＴＲ５０ｍｓ，Ｔｅ７ｍｓ，层厚１ｍｍ，无间距。结果：有２２例分别由脑血管造影，ＤＳＡ检查及外科手术证实。结论：３Ｄ－ＴＯＦ法ＭＲＡ诊断脑血管病变有重要价值，是一种简便，快速，有效的检查方法。     

MR angiography of internal carotid arteries: breath-hold Gd-enhanced 3D fast imaging with steady-state precession versus unenhanced 2D and 3D time-of-flight techniques

PURPOSE: The purpose of this work was to compare Gd-enhanced breath-hold fast imaging with steady-state precession (Gd-FISP) with unenhanced time-of-flight (TOF) sequences in evaluating internal carotid arteries (ICAs). METHOD: Thirty patients underwent three unenhanced TOF sequences [2D traveling saturation (Travelsat); 3D tilted optimized nonsaturated excitation (TONE); TOF 3D Multislab] and two breath-hold 3D Gd-FISP sequences with automated intravenous contrast agent injection (axial and coronal). ICAs were classified as normal (no stenosis); with mild (<30%), moderate (30-70%), or severe stenosis; or occluded (100%). Digital subtraction angiography (DSA) with aortic arch injection was used as a reference technique. RESULTS: DSA revealed 20 normal ICAs; 11 mild, 9 moderate, and 14 severe stenoses; and 2 occlusions. DSA and all MR angiography (MRA) sequences diagnosed the occlusion of four common carotid arteries. The TOF 2D overestimated 10 stenoses, TOF 3D TONE 9, and TOF 3D Multislab 5; Gd-FISP 3D overestimated only 2 of them, reaching the highest sensitivity and specificity for severe stenoses. Significant differences were found between the overestimation of Gd-FISP and each of the three unenhanced sequences (0.0020 < p < 0.0313, Wilcoxon and McNemar tests). Severe artifacts were observed with TOF techniques only. CONCLUSION: Gd-FISP is an interesting, largely artifact-free improvement for MRA of ICAs.     

Acute subarachnoid Haemorrhage: 3D time-of-flight MR angiography versus intra-arterial digital angiography

To evaluate the efficacy and reliability of 3D time-of-flight MR angiography (TOF MRA) as a noninvasive procedure, 27 patients with acute subarachnoid haemorrhage (SAH) were studied with MRA immediately before or after intra-arterial digital subtraction angiography (DSA). 3DTOF MRA was performed with an axial slab of 60 mm centred on the circle of Willis and isotropic voxels. DSA showed 22 aneurysms and 1 dural arteriovenous fistula in 21 patients; the aneurysms ranged in size from 2 to 8 mm. MRA failed to show 2 small aneurysms, at the origin of the posterior and anterior communicating arteries. The 3D display of the intracranial vessels obtained with maximum intensity projection (MIP) or targetted MIP sometimes rendered the aneurysms better than DSA. However, due to its high spatial resolution, DSA more clearly defined the overall anatomy of the walls of the normal and abnormal vessels.1992 Scientific Award of the ESNR     

Carotid artery stenosis: intraindividual correlations of 3D time-of-flight MR angiography, contrast-enhanced MR angiography, conventional DSA, and rotational angiography for detection and grading

PURPOSE: To compare three-dimensional (3D) time-of-flight (TOF) MR angiography, contrast-enhanced MR angiography, digital subtraction angiography (DSA), and rotational angiography for depiction of stenosis. MATERIALS AND METHODS: The study had Ethics Committee approval, and each patient gave written informed consent. Forty-nine patients (18 women, mean age, 67.2 years +/- 9.1 [+/- standard deviation], and 31 men, mean age, 63.1 years +/- 8.0) with symptomatic stenosis of internal carotid artery (ICA) diagnosed at duplex ultrasonography underwent transverse 3D TOF MR angiography with sliding interleaved kY acquisition and coronal contrast-enhanced MR angiography, followed by DSA and rotational angiography within 48 hours. MR angiography was performed at 1.5-T with a cervical coil. Contrast-enhanced MR angiograms were obtained after a bolus injection of 20 mL of gadobenate dimeglumine. Maximum ICA stenosis on maximum intensity projection and source images was quantified according to NASCET criteria. Correlations for 3D TOF MR angiography, contrast-enhanced MR angiography, DSA, and rotational angiography were determined by means of cross tabulation, and accuracy for detection and grading of stenoses were calculated. Data were evaluated with analysis of variance, Wilcoxon signed rank test, and McNemar test, all at significance of P < .05. RESULTS: Ninety-eight ICAs were evaluated at contrast-enhanced MR angiography, DSA, and rotational angiography, and 97 were evaluated at 3D TOF MR angiography. Correlations for contrast-enhanced MR angiography, 3D TOF MR angiography, and DSA relative to rotational angiography were r2 = 0.9332, r2 = 0.9048, and r2 = 0.9255, respectively. Lower correlation (r2 = 0.8593) was noted for contrast-enhanced MR angiography and DSA. Respective sensitivity and specificity for detection of hemodynamically relevant stenosis relative to rotational angiography were 100% and 90% for contrast-enhanced MR angiography, 95.5% and 87.2% for 3D TOF MR angiography, and 88.6% and 100% for DSA. Four of 31 severe stenoses were underestimated at DSA, and three were underestimated at contrast-enhanced MR angiography. Three severe stenoses were underestimated at 3D TOF MR angiography, and one was misclassified as occluded. Of 13 moderate (50%-69%) stenoses, one was overestimated at contrast-enhanced MR angiography, two were underestimated and three overestimated at 3D TOF MR angiography, and two were underestimated at DSA. CONCLUSION: DSA results in an underestimation of ICA stenosis compared with rotational angiography. Contrast-enhanced MR angiography correlates best with rotational angiography.     

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.