Value of a contrast agent in equivocal carotid ultrasound studies: pictorial essay

The aim of the present study was to assess the use of an echo-enhancing agent (Levovist; Schering AG) in equivocal carotid bifurcation ultrasound studies and compare the information obtained with digital subtraction angiography (DSA). Contrast-enhanced carotid ultrasound studies were performed on 30 carotid bifurcations in 28 patients. The standard carotid ultrasound examinations were considered equivocal for two reasons: apparent acute internal carotid artery occlusions (n = 10), and possibly patent but critically stenosed internal carotid arteries with the residual flow lumen being incompletely visualized (n = 20). All patients underwent subsequent carotid digital subtraction angiography. All patients with apparent acute carotid occlusions (n = 10) were correctly characterized on contrast-enhanced ultrasound when compared with DSA. The majority were complete occlusions (n = 8) although in two cases there were critical carotid stenoses requiring surgical endarterectomy. In the 'incompletely visualized lumen' group (n = 20), the majority (n = 16) were correctly characterized on contrast enhanced ultrasound: 13 cases of critically stenotic but patent internal carotid arteries, two cases without a haemodynamically significant stenosis and one case of a carotid occlusion with patent vasa vasorum. One of the critical carotid stenoses was prospectively reported as occluded on the 'gold standard' angiography. In three cases the flow lumen was still incompletely visualized due to calcified plaque despite an echo-enhancing agent; angiography revealed no significant stenosis in all cases. There was one false negative for internal carotid occlusion. This occurred early in the series and could be considered to be a technical error. Importantly, there were no false positives for carotid occlusion. Contrast-enhanced carotid ultrasound significantly improves diagnostic confidence in equivocal carotid ultrasound studies. In appropriate clinical settings this may reduce the need for subsequent carotid angiography.     

三维对比剂增强MR血管成像对颈部动脉病变的诊断价值

目的　分析三维对比剂增强MR血管成像 (3DCE MRA)显示的颈部动脉常见病变 ;与DSA比较 ,明确 3DCE MRA诊断颈部动脉病变的价值。方法　对 741例超声多普勒怀疑颈部动脉疾病的患者进行 3DCE MRA成像 ,并根据其病变表现总结分类。 2 0 6例病人同时行DSA检查 ,将颈部动脉分为颈总、颈内、颈外、锁骨下及椎动脉 5个部位 ,由 2位放射学专家独立评估DSA及 3DCE MRA血管资料。结果　 3 6 7%病例 (2 72 / 741)显示无异常。 63 2 9% (469/ 741)显示颈部动脉有病变 ,共计 82 7段 ,其中动脉粥样斑块占 3 4 2 2 % (2 83段 ) ,动脉狭窄占 3 4 46% (2 85段 ) ,动脉闭塞占 3 3 8% (2 8段 ) ,动脉发育纤细占 14 87% (12 3段 ) ;动脉开口变异占 3 87% (3 2段 ) ,动脉扭曲占 3 63 % (3 0段 ) ,动脉瘤占 0 72 % (6段 ) ,动脉夹层占 1 2 1% (10段 ) ,肿瘤包绕或推压动脉占 1 45% (12段 ) ,术后复查占2 18% (18段 )。对 2 0 6例的 412段血管与DSA比较 ,3DCE MRA在颈总动脉、颈内动脉及椎动脉的阳性检出率差异有显著性意义 (P <0 0 1) ,主要是对动脉粥样斑块 (2 56段与 2 83段 )和动脉狭窄 (2 58段与 2 85段 )存在一定的高估。但对 412段血管整个样本 ,两种方法在同一部位诊断各种血管病变差异无显著性意义 (P >0 0     

Spiral CT angiography and selective digital subtraction angiography of internal carotid artery stenosis.

PURPOSETo determine whether spiral CT angiography allows accurate, quantitative evaluation of anatomic abnormalities, including detection of additional lesions, delineation of plaque morphology, and estimation of degree of internal carotid artery stenosis.METHODSSpiral CT angiography with a maximum intensity projection technique was compared with selective digital subtraction angiography (DSA) in 92 carotid arteries. The category of stenosis was determined according to the North American Symptomatic Carotid Endarterectomy Trial: mild (0% to 29%), moderate (30% to 69%), severe (70% to 99%), and occlusion (100%).RESULTSIn 78 (85%) of the 92 cases, spiral CT angiography and selective DSA demonstrated the same degree of stenosis. All occlusions (n = 19) were diagnosed correctly with spiral CT angiography. Spiral CT angiography agreed with selective DSA in the classification of stenosis in 59% of the group with mild stenosis, in 82% of the group with moderate stenosis, and in 90% of the group with severe stenosis. In the groups with mild (n = 13), moderate (n = 9), and severe (n = 27) stenosis, correlation of spiral CT angiography with selective DSA was significant. Calcified plaques were readily diagnosed with the use of spiral CT angiography but delineation of ulcers was poor. Tandem lesions were not visible owing to the limited coverage.CONCLUSIONSpiral CT angiography is useful for the detection of proximal internal carotid stenoses that are greater than 30%. Depiction of mild stenoses appears to be limited. CT is superior for the detection of calcified plaques but it is not useful for the detection of ulcers.     

Carotid artery stenosis: contrast-enhanced MR angiography with two different scan times compared with digital subtraction angiography

Contrast enhanced magnetic resonance angiography (CE MRA) is a non-invasive alternative to conventional digital subtraction angiography (DSA). CE MRA is increasingly used as a complement to Duplex in the preoperative assessment of carotid artery stenosis. The purpose of this study was to determine if CE MRA could replace preoperative DSA. CE MRA with a scan time of 10 or 28 s was performed in 24 consecutive patients who were scheduled for preoperative DSA because of Duplex-verified severe carotid artery stenosis. Two neuroradiologists measured the degree of stenosis with three different methods, and the image quality was evaluated. DSA was used as the gold standard. For detection of severe stenosis (N. American symptomatic carotid endarterectomy trial (NASCET) > or =70%; European symptomatic carotid endarterectomy trial (ECST) > or =80%; common carotid artery method (CCAM) > or =80%), the sensitivity of CE MRA maximum intensity projection (MIP) compared with DSA was 82%-100 %, the specificity was 74%-93% and the accuracy was 77%-90%. The inter-observer agreement was higher, the image quality was better and the intracranial main arteries were better visualized with the 28 s than with the 10 s scan time. The enhancement of the jugular veins seen in 17% of the 10 s scans and in 58% of the patients with the 28 s scans did not interfere with the evaluation of the carotid arteries. CE MRA, preferably with a scan time of 28 s, can replace DSA in the preoperative assessment of most patients with carotid artery stenosis.     

MSCT颈部血管成像在颈动脉体瘤诊治中的价值

目的:探讨MSCT颈部血管成像在颈动脉体瘤诊断中的价值.方法:对9例颈动脉体瘤患者行MSCT颈部CTA扫描,利用工作站对颈部血管及肿瘤血管进行重组,并对疾病进行诊断.所有患者同时行彩色多普勒超声(CDFI)检查,2种检查方法在3 d内完成.所有患者均经手术或数字减影血管造影(DSA)证实.结果:9例患者MSCT共发现肿瘤10个,1例为双侧发病,最大者11.6 cm×12 cm,最小者为1.7 cm×1.6 cm.MSCT均诊断为颈动脉体瘤,并可清晰显示肿瘤血管及肿瘤与邻近血管的关系.CDFI诊断颈动脉体瘤8例,1例诊断为神经纤维瘤,6例CDFI能显示肿瘤与邻近血管的关系.与手术及DSA结果对照,MSCT诊断准确率为100%,其显示的肿瘤血管及肿瘤与邻近血管的关系与DSA及手术所见相符合,CDFI诊断准确性为88.89%,但其不能立体、直观地显示肿瘤血管.结论:MSCT颈部血管成像不但能准确地诊断颈动脉体瘤,立体、直观地显示肿瘤血管,同时还能清晰地显示肿瘤与邻近血管的关系,为手术提供可靠的信息,是颈动脉体瘤首选的检查方法之一.     

颈动脉体瘤的DSA诊断

目的：加深对颈动脉体瘤DSA表现特点的认识，探讨其诊断及介入治疗价值。方法：由两位有经验的放射学医师按双盲法对12例动脉体瘤的DSA造影资料进行回顾性分析，然后共同讨论并达成一致意见。结果：DSA均能明确诊断。所有患者均见颈动脉分叉角度增大，颈内、外动脉移位；大部分瘤体以颈外动脉供血为主，血供较丰富；6例患者瘤体包绕颈动脉者可见局部血管受侵。2例患者栓塞后造影见肿瘤染色范围缩小，且术中出血明显减少。结论：DSA是颈动脉体瘤的诊断和术前评估的有效手段，术前栓塞有利于减少术中出血。     

3DFT MR angiography of the carotid bifurcation: potential and limitations as a screening examination

The authors compared the three-dimensional Fourier transform (3DFT) time-of-flight magnetic resonance (MR) angiograms in 38 patients initially studied with selective intraarterial digital subtraction angiography (DSA) for suspected arteriosclerotic disease of the carotid bifurcation. MR angiograms were successfully obtained in 65 of the 75 carotid arteries (87%) visualized with DSA. DSA and MR angiographic studies were assessed for percentage area stenosis by two independent observers on two occasions. Statistical tests indicated consistency in interpretation for each observer as well as between observers. No significant difference was found between the two modalities in ability to depict changes in percentage area stenosis. For the 32 right carotid arteries in the comparison, the median for the difference between MR angiography and intraarterial DSA was 1.83% (range, -22.38% to 55.60%); for the 33 visualized left carotid arteries, it was 0.00% (range, -20.55% to 49.95%). Receiver operating characteristic analysis indicated that technically adequate MR angiography may be a sensitive screening examination for stenoses.     

Colour flow Doppler ultrasound of the carotid bifurcation: can it replace routine angiography before carotid endarterectomy?

The objective of this study was to assess the diagnostic accuracy of colour flow Doppler ultrasound (CFD) and its potential to replace digital subtraction angiography (DSA) before carotid endarterectomy (CEA). All patients undergoing CFD of the carotid bifurcation in our department over a period of 1-1/2 years for whom both CFD and DSA results were available were included in the study. We evaluated the feasibility of CFD, its diagnostic accuracy and its potential to diagnose clinically significant stenosis (50%, 70% and 90% NASCET type diameter stenosis) compared with DSA. 225 carotid bifurcations in 116 patients met the criteria for evaluation (biplane arterial DSA without superimposition). Data analysis yielded the following diagnostic performance of CFD: sensitivity for a 50% stenosis 91.4% (95% confidence interval (CI) 83.3--96.2%), specificity 93.2% (95% CI 87.1--96.8%) and accuracy 92.4% (95% CI 88.4--95.4%); sensitivity for a 70% stenosis 89.2% (95% CI 81.9--94.1%), specificity 96.2% (95% CI 90.5--98.6%) and accuracy 92.4% (95% CI 88.4--95.4%). In 9 of 116 cases, carotid angiography was used to evaluate inconclusive CFD results. DSA disclosed relevant information not suspected by CFD in only 1 of the 116 cases. Thus, 91% (106/116) of the angiographies could have been dispensed with without loss of information. One major stroke occurred during diagnostic DSA. We conclude that DSA of the carotid arteries is unnecessary when CFD is unequivocal. The diagnostic gain of DSA must be counterweighted against its potential risks.     

颈部副神经节瘤的DSA诊断研究(附17例分析)

目的 探讨颈部副神经节瘤的ＤＳＡ诊断价值。方法 总结经病理证实的动脉体瘤（ＣＢＴ）１２例、颈静脉瘤（ＣＪＴ）５例,研究ＤＳＡ表现,并与其他颈部肿块性病变进行对照。结果 副神经节瘤主富血供型（ＣＢＴ１１例,ＧＪＴ３例）,ＤＳＡ能清楚显示肿瘤血管细节及肿瘤与相邻血管的整体关系。ＣＢＴ颈总动脉分驻开大呈握球状（１２例）、枕动脉近段向前上推移（１２例）、咽升动脉肿瘤中心供血（１０例）具有特征性,３例恶变者     

Effect of the geometry of atherosclerotic carotid artery lesions on their angiography image--an arteriography study

Atherosclerotic lesions of the carotid arteries are frequently located eccentrically and are of asymmetric configuration. For their angiographic detection at least two orthogonal views are mandatory. The carotid bifurcations, the proximal internal carotid artery and the carotid siphon can be visualised free from vessel overlap only via often mandatory lateral views that must be obtained by selective arteriography (IA DSA). Smaller lesions and ulcerations of the carotid bifurcation area may be misinterpreted with nonselective IA DSA and IV DSA because of their geometry.     

Contrast-enhanced 3D MR angiography of the carotid artery: comparison with conventional digital subtraction angiography

BACKGROUND AND PURPOSE: Since 1996, several preliminary studies have shown the usefulness of contrast material-enhanced MR angiography for imaging supraaortic vessels. The aim of this study was to compare the accuracy of contrast-enhanced 3D MR angiography with that of digital subtraction angiography (DSA) in the evaluation of carotid artery stenosis. METHODS: A blinded comparison of first-pass contrast-enhanced MR angiography with conventional DSA was performed in 120 patients (240 arteries). MR angiography was performed with a 1.5-T magnet with gradient overdrive equipment, by using a coronal radiofrequency-spoiled 3D fast low-angle-shot sequence after the intravenous injection of gadodiamide. The guidelines of the North American Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection (MIP) images and conventional catheter angiograms. RESULTS: Grading of stenoses on MR angiograms agreed with grading of stenoses on DSA images in 89% of arteries. In the severe stenosis group (70-99%), agreement was 93%. All internal carotid occlusions (n = 28) and seven of nine pseudo-occlusions were accurately detected with contrast-enhanced MR angiography. The correlation between MR angiography and DSA for determination of minimal, moderate, and severe stenoses and occlusion was statistically significant (r = 0.91, P<.001). CONCLUSIONS: This investigation with a large number of patients confirms that contrast-enhanced MR angiography could become a diagnostic alternative to DSA in the treatment of patients with carotid artery disease.     

旋转DSA的临床应用

目的　评价旋转DSA的临床应用价值。方法　采用PHILIPSV5 0 0 0数字成像系统 ,对 3 0例患者实施旋转式数字减影血管造影 48例次。其中脑动脉 8例 ,颈动脉 2例 ,四肢动脉 7例 ,肝动脉 2例 ,肺动脉 1例 ,髂动脉 2例 ,腹主动脉 1例 ,肾动脉 2例以及子宫动脉 5例。结果　 3 0例患者 2 8例良好地显示了病变处血管起源、走行、分布、数目、轮廓以及假性动脉瘤的瘘口。结论　旋转式数字减影血管造影能够清楚显示所检查部位的血管结构 ,对病变的术前诊断和制定手术计划具有重要的参考价值。     

Diagnostik von Karotisstenosen mit der mehrzeiligen CT-Angiographie

BACKGROUND: The accurate evaluation of carotid artery stenoses is important for therapeutic decision making. Catheter digital subtraction angiography (DSA) still represents the gold standard, while the advent of multislice CT (MSCT) has led to improved temporal and spatial resolutions of CTA. MATERIAL AND METHODS: In a pilot study, we investigated 14 diseased vessels in 9 symptomatic patients (7m, 2f; mean age 60.7+/-10,9 years) comparing biplanar DSA with standardized 16-slice MS-CTA. The degree of stenosis was evaluated in a consensus reading following modified NASCET criteria. RESULTS: DSA demonstrated 4 occlusions, 5 high-grade stenoses (>70%) and 5 lower-grade stenoses (<70%). One dissecting, infrapetrous stenosis was not adequately quantified by CTA due to a close topographic relation to the skull base. In the carotid bifurcation (n=13), an excellent correlation was demonstrated between DSA and CTA with a correlation coefficient of 0.99. CONCLUSION: MS-CTA has a good diagnostic potential in the evaluation of carotid artery stenoses. Larger studies will need to demonstrate the relative diagnostic value for different subtypes of stenosis and for different reader experience levels.     

Time-resolved contrast-enhanced magnetic resonance angiography of the carotid arteries: diagnostic accuracy and inter-observer variability compared with selective catheter angiography

RATIONALE AND OBJECTIVES: To assess the diagnostic accuracy and interobserver variability of contrast-enhanced magnetic resonance angiography (CE-MRA) in a time-resolved technique compared with digital subtraction angiography (x-ray DSA) in patients with suspected stenoses of the internal carotid artery. MATERIALS AND METHODS: A total of 43 patients were enrolled in this prospective study. All patients underwent selective x-ray DSA involving a total of 84 carotid arteries. CE-MRA was performed in a time-resolved technique with a fast gradient-echo sequence on a 1.5 T MR scanner: TR 3.8 milliseconds, TE 1.49 milliseconds. Four consecutive measurements, each a duration of 10 seconds, were performed with omission of measuring bolus transit time. Four independent radiologists scored the degree of stenosis. The interobserver variability was calculated for CE-MRA and x-ray DSA. RESULTS: In the 43 cases, at least one MRA measurement showed arterial contrast without venous degradation. Compared with x-ray DSA the mean sensitivity and specificity for grading stenosis > or = 70% were 98% and 86%, respectively. The interobserver agreement was substantial with no significant difference between CE-MRA (kappa value 0.794) and x-ray DSA (kappa value 0.786). CONCLUSIONS: The short acquisition time of a fast CE-MRA sequence allows a selective visualization of the internal carotid arteries without degradation from venous enhancement. It is a reliable method with a good interobserver agreement.     

烟雾病数字减影血管造影的诊断价值

目的评价数字减影血管造影(DSA)对烟雾病的诊断价值。材料与方法对13例烟雾病患者行DSA检查及回顾性分析。结果13例烟雾病DSA表现为不同程度颈内动脉分叉处血管狭窄或闭塞,侧支循环形成呈烟雾状。结论DSA可清晰地显示烟雾病血管狭窄程度或闭塞的部位及侧支循环情况,为临床治疗提供直接的影像学资料。     

Intravenous DSA examination of patients with suspected cerebral ischemia

We analyzed the role of intravenous digital subtraction angiography (DSA), with neck and intracranial views as a definitive pretherapy study, in patients who had symptomatic cerebral ischemia. Eighty-six patients, 25 of whom had subsequent carotid thromboendarterectomy, were examined. An adequate pretherapy intravenous DSA study allowed us to define each carotid bifurcation as either normal, having insignificant stenosis, or having significant stenosis, and the examination excluded significant tandem stenosis in the intracranial internal carotid arteries. Adequate pretherapy intravenous DSA studies were obtained in 73% of patients, including 50% of those in the presurgical group. Selective carotid arteriography was not required in these patients. Inadequate presurgical studies were predominantly due to plaque misregistration, inadequate projection, and superimposition that obscured the proximal internal carotid arteries. Selective carotid arteriography was performed in these patients prior to surgery. Inadequate studies prior to initiation of medical therapy were predominantly due to soft tissue misregistration artifact, and superimposition. Intravenous DSA is a valuable screening test and can be used to guide therapy in the majority of patients who have symptomatic cerebral ischemia.     

Relative safety of intravenous digital subtraction angiography over other methods of carotid angiography and impact on clinical management of cerebrovascular disease

Data from a multicentre survey based on three London teaching hospitals on the relative safety and clinical utility of intravenous carotid digital subtraction angiography (DSA) over intra-arterial DSA and conventional carotid angiography are presented. The incidence of stroke during intra-arterial DSA was 0.7% (n = 538) and during conventional angiography was 0.8% (n = 780). The incidence of stroke during intravenous DSA was zero (n = 3710). When it constituted the initial investigation, intravenous DSA achieved a 93.8% replacement value over intra-arterial studies as a whole (n = 474) and 89% replacement value for patients having carotid endarterectomy (n = 99). It was also noted that the installation of DSA equipment at one unit coincided with a sixfold increase in the number of carotid angiographic examinations and an almost threefold increase in carotid endarterectomies.     

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     

26例颈动脉体瘤的外科治疗体会

目的：探讨颈动脉体瘤(Carotid body tumor,CBT)的诊断和治疗经验。方法：26例患者，分别血管多普勒B超检测及单侧血管造影术或数字减影血管造影术(Digital subtrasound angiography，DSA)，明确诊断。术前均行颈动脉压迫试验。手术治疗，其中瘤体剥离式切除9例；颈外动脉同时切除15例；颈内动脉部分切除，颈总、颈内人造血管搭桥术1例；颈总动脉分叉处切除、颈内外动脉吻合1例。结果：除2例合并脑部并发症并治愈，无1例死亡。结论：DSA对CBT的诊断最具权威性，术前颈动脉压迫训练，正确的术式选择是减少脑部并发症保证手术成功的关键。     

Prospective evaluation of carotid artery stenosis: elliptic centric contrast-enhanced MR angiography and spiral CT angiography compared with digital subtraction angiography

BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) is the reference standard for assessing carotid arteries, it is uncomfortable for patients and has a small risk of disabling stroke and death. These problems have fueled the use of spiral CT angiography and MR angiography. We prospectively compared elliptic centric contrast-enhanced MR angiography and spiral CT angiography with conventional DSA for detecting carotid artery stenosis. METHODS: Eighty carotid arteries (in 40 symptomatic patients) were assessed. Elliptic centric MR and spiral CT angiographic data were reconstructed with maximum intensity projection and multiplanar reconstruction techniques. All patients had been referred for DSA evaluation on the basis of findings at Doppler sonography, which served as a screening method (degree of stenosis > or = 70% or inconclusive results). Degree of carotid stenosis estimated by using the three modalities was compared. RESULTS: Significant correlation with DSA was found for stenosis degree for both elliptic centric MR and spiral CT angiography; however, the correlation coefficient was higher for MR than for CT angiography (r = 0.98 vs r = 0.86). Underestimation of stenoses of 70-99% occurred in one case with elliptic centric MR angiography (a 70% stenosis was underestimated as 65%) and in nine cases with spiral CT angiography, in comparison to DSA findings. Overestimation occurred in two cases with MR angiography (stenoses of 65-67% were overestimated as 70-75%). With CT, overestimation occurred in seven cases; a stenosis of 60% in one case was overestimated as 70%. Both techniques confirmed the three cases of carotid occlusion. With elliptic centric MR angiography, carotid stenoses of 70% or greater were detected with high sensitivity, 97.1%; specificity, 95.2%; likelihood ratio (LR) for a positive test result, 20.4; and ratio of LR(+) to LR(-), -0.3. With spiral CT angiography, sensitivity, specificity, LR(+), and LR(+):LR(-) were 74.3%, 97.6%, 31.2, and 0.3, respectively. CONCLUSION: Elliptic centric contrast-enhanced MR angiography is more accurate than spiral CT angiography to adequately evaluate carotid stenosis. Furthermore, elliptic centric contrast-enhanced MR angiography appears to be adequate to replace conventional DSA in most patients examined.