16层螺旋CT在下肢动脉闭塞性疾病中的应用价值

目的:探讨16层螺旋CT血管成像术在诊断下肢动脉闭塞性疾病中的应用价值。方法:对42例临床疑为外周动脉闭塞性疾病的患者行下肢动脉16层螺旋CT血管造影(CTA),扫描范围从肾动脉水平达足底。薄层重建横断面图像传入HP xw8000工作站,进行血管三维重建。所有患者于CTA检查前或后2周内行数字减影血管造影(DSA)。以DSA为金标准,评价CTA诊断的准确性。结果:在882个动脉节段中,870个节段在CTA与DSA均可以显示,在DSA图像上,狭窄闭塞的节段共260个(轻度狭窄32段,中度狭窄24段,重度狭窄44段,闭塞160段),最大密度投影(MIP)显示中度以上狭窄的敏感性、特异性及准确性分别为99.1%、99.7%、99.5%。结论:16层螺旋CT在评估下肢动脉闭塞性疾病方面与常规血管造影结果无明显差别,是下肢动脉闭塞性疾病理想的影像学检查手段,可部分替代DSA检查。     

CTA与DSA在冠状动脉斑块及血管狭窄中的对比研究

目的探究64排螺旋CT在冠状动脉病变中的应用,以提高CTA在冠状动脉血管狭窄的诊断水平。方法分析40例冠心病确诊病例的患者分别行冠状动脉CT造影检查及冠状动脉DSA检查的临床及影像资料,比较两种方法对冠状动脉狭窄的影像学诊断及斑块性质对血管狭窄相关性的分析。结果1)MSCTA各节段狭窄冠状动脉分支及相应狭窄程度冠状动脉检出率与DSA比较,差异不明显,不存在统计学意义(P>0.05);2)CTA诊断结果显示,冠状动脉轻度狭窄多为钙化斑块(71.4%),中/重度狭窄多为混合斑块,分别为58%和56.5%。结论MSCTA对狭窄冠状动脉的确诊率与DSA相近,而且能够准确直观的显示冠状动脉斑块性质,不仅具有无创、安全的特点,还对指导冠心病的诊断预防及治疗具有较高临床应用价值。     

CTA与DSA评估冠心病冠状动脉狭窄程度的临床价值

目的 探讨CT血管成像(CTA)与数字减影血管造影(DSA)评估冠心病(CHD)冠状动脉狭窄程度的临床价值。方法选取78例疑似CHD患者，首先行CTA检查，并在随后7天内行DSA检查。将DSA作为诊断金标准，分析CTA对冠状动脉阳性病变的诊断结果。结果 经DSA金标准诊断阳性65例，阴性13例，其中CTA诊断阳性64例，阴性12例。CTA对冠状动脉阳性病变诊断的阴性预测值为92.31%、阳性预测值98.46%、灵敏度98.46%、特异度92.31%、符合率97.44%,一致性分析Kappa值分别为0.890,0.932,0.890,0.932,0.928。DSA与CTA对CHD冠状动脉狭窄程度的检查结果比较，差异无统计学意义(P>0.05)。结论 CTA对于CHD具有较高的诊断价值，能够有效识别冠状动脉狭窄程度与斑块类型。     

64层螺旋CT血管成像对下肢动脉系统疾病的应用价值

目的:探讨64层螺旋CT血管成像术在下肢动脉疾病中的应用价值及技术优势。方法:对21例疑有下肢动脉疾病患者行64层螺旋CT增强扫描,扫描范围从肾动脉水平达足底。薄层重建横断面图像传入Wizard工作站,进行血管三维重建。其中21例结合常规血管造影评价64层螺旋CT血管成像术(CTA)的准确性。结果:在441个动脉节段中,435个节段在CTA与DSA均可以显示,在DSA图像上,狭窄闭塞的节段共130个(轻度狭窄16段,中度狭窄12段,重度狭窄22段,闭塞80段),最大密度投影(MIP)显示中度以上狭窄的敏感性、特异性及准确性分别为:99.1%、99.7%、99.5%。结论:64层CT血管成像是一种高度准确、非侵袭性的成像技术,在评估下肢动脉疾病方面与常规血管造影结果无明显差别,是下肢动脉疾病较好的影像学检查手段。     

多层螺旋CT和三维屏气MR冠状动脉成像的对比研究

目的比较16层螺旋CT（16 multi-detector CT,16-MDCT）冠状动脉血管造影（CTA）和三维屏气冠状动脉MR血管造影（MRA）的图像质量以及诊断冠状动脉显著性狭窄（＞50%）的准确性.方法40例疑有冠心病患者在3 d内均行冠状动脉CTA和MRA检查,其中31例患者在2周内行冠状动脉造影检查.将冠状动脉分成9个节段（右冠状动脉近、中、远段,左冠状动脉主干,前降支近、中、远段和旋支近、远段）,由2名影像科医生共同对各个节段的图像质量按0～4级评分,比较CTA和MRA上各个节段的图像质量.以冠状动脉造影为标准,计算并比较CTA和MRA诊断31例冠状动脉显著性狭窄（＞50%）各项准确性指标.结果CTA在右冠状动脉中段的图像质量低于MRA,右冠状动脉近段二者无区别,其他节段均优于MRA.冠状动脉造影显示31例患者共有43个节段狭窄＞50%,CTA和MRA分别正确诊断出36和27个,其敏感性、特异性、阳性预测值和阴性预测值分别为83%、84%、49%、97%和63%、90%、55%、93%.结论除右冠状动脉中段,CTA大部分节段的图像质量优于MRA.CTA诊断冠状动脉显著性狭窄的敏感性高于MRA,但特异性低于MRA.冠状动脉CTA和MRA均表现了较高的阴性预测值,对排除冠状动脉狭窄具有临床价值.     

心房颤动患者的64层螺旋CT冠状动脉成像的初步临床研究

目的 探讨64层螺旋CT在心房颤动患者冠状动脉CT血管成像(CTA)中的应用价值.方法 分析31例心房颤动患者的冠状动脉CTA图像质量,利用血管分析软件判断血管有无狭窄并测量狭窄率,其中10例患者的冠状动脉CTA结果与冠状动脉造影(CAG)结果进行了对照分析.对于不同心率患者图像质量的比较分析采用多个独立样本(等级资料)的非参数秩和榆验.结果所有患者均采用绝对值时间法重组心脏容积数据.对31例患者中364段血管节段进行成像质量分析:心率为47～69次/min组图像质量为优、良、中和差的血管节段数分别为85、41、5和8个,心率为70～79次/min组分别为63、16、13和15个,心率为80～105次/min组分别为46、25、23和24个,3组间成像质量差异有统计学意义(H=22.08,P＜0.01).10例与CAG进行对照,共分析冠状动脉血管125段,CTA诊断血管狭窄程度≥50%的敏感度为85.0%(17/20),特异度为95.2%(100/105),阳性预测值为77.3%(17/22),阴性预测价值为97.1%(100/103).冠状动脉CTA低估了3段血管的病变,过度评价了5段血管.结论64层螺旋CT对心房颤动患者进行冠状动脉CTA检查具有一定的临床价值.     

Flash双源CT冠状动脉成像与DSA的对比分析

目的探讨双源CT冠状动脉成像(dual source computed tomography coronary angiography,DSCTA)与冠状动脉数字减影(digital subtraction arteriography,DSA)诊断冠状动脉疾病的效果。方法对44例临床怀疑冠心病而行CT冠状动脉检查的患者采用Flash双源CT冠状动脉成像检查,并以DSA为金标准进行对比分析。结果本组患者均顺利完成DSCTA,均可见完整清晰的显影血管,共计检查了524段动脉节段,MSCTA检查发现无狭窄420段,轻度狭窄20段,中度狭窄28段,重度狭窄56段。经冠状动脉造影检查确诊冠心病阳性28例,阴性16例;双源CT冠脉成像诊断44例患者中真阳性27例,3例假阳性,13例真阴性,1例假阴性。经分析,DSCTA诊断符合率为90.91%,敏感性为96.43%、特异性为81.25%。与金标准DSA的检查结果进行对比分析发现,DSCTA诊断冠状动脉狭窄的一致性较好,kappa值为0.87。结论双源CT冠状动脉成像技术可作为冠心病患者筛查手段或低危冠心病患者的复查检查手段,具有可靠、简便、准确、快捷的优点。     

TCD、CTA、DSA检查颈内动脉狭窄的临床价值分析

目的探讨经颅多普勒超声(TCD)、CT血管造影(CTA)及减影血管造影(DSA)检查颈内动脉狭窄临床价值。方法对60例高度怀疑颈内动脉狭窄的患者行TCD、DSA与头颅CTA检查,以DSA诊断为金标准,比较TCD和CTA检查的敏感性、特异性和符合率。结果 60例患者480条受检的血管中,经DSA检查为正常、中度、重度狭窄的血管条数分别为38条,57条及55条。CTA、TCD检查的敏感性、特异性和符合率分别为95.5%、80.0%、92.7%和87.1%、75.0%、80.7%。TCD结果显示重度狭窄段的收缩期流速显著高于中度狭窄段的流速,P0.05。结论 CTA、DSA作为经典检测方法,均能准确显示颈内动脉狭窄程度,TCD方法对重度狭窄具有较高的诊断价值。     

经颅多普勒超声、CT血管造影及减影血管造影对颈内动脉狭窄的诊断分析

目的探讨经颅多普勒超声(TCD)、CT血管造影(CTA)及减影血管造影(DSA)三种检查方法在颈内动脉狭窄诊断中的临床应用价值。方法对60例高度怀疑颈内动脉狭窄的患者行TCD、DSA与头颅CTA检查,以DSA诊断为金标准,比较TCD和CTA检查的敏感性、特异性和符合率。结果 60例患者480条受检的血管中,经DSA检查为正常、中度、重度狭窄的血管条数分别为38条,57条及55条。CTA、TCD检查的敏感性、特异性和符合率分别为95. 5%、80. 0%、92. 7%和87. 1%、75. 0%、80. 7%。TCD结果显示重度狭窄段的收缩期流速显著高于中度狭窄段的流速,P 0. 05。结论 CTA、DSA作为经典检测方法,均能准确显示颈内动脉狭窄程度,TCD方法对重度狭窄具有较高的诊断价值。     

64层螺旋CT在冠状动脉搭桥术后随访中的初步应用

目的:评价64层螺旋CT在冠状动脉搭桥术后随访中的应用价值.方法:14例搭桥术后患者行64层螺旋CT冠状动脉造影检查,分别评价CT图像桥血管近远端吻合口、桥血管本身和吻合口远端引流血管的图像质量及冠状动脉图像质量.有选择性冠状动脉造影作对照的病例,评价CT诊断桥血管通畅性和冠状动脉是否存在狭窄的可靠性,以管腔狭窄大于50%作为诊断血管狭窄的指标.结果:14例患者共发现桥血管33根,桥血管近远端吻合口可评价率分别为93.9%(31/33)和90.9%(30/33);桥血管本身近、中、远三段的可评价率分别为97.0%(32/33)、100%(33/33)和97.0%(32/33);远端引流血管的可评价率为93.9%(31/33).CTA共显示冠状动脉139段,冠状动脉节段可评价率为69.1%(96/139).CTA对评价桥血管的通畅性和冠状动脉是否存在狭窄未出现假阳性及假阴性结果.结论:64层螺旋CT在冠状动脉搭桥术后随访中具有重要的临床应用价值.     

Ureteropelvic junction obstruction: use of helical CT for preoperative assessment--comparison with intraarterial angiography

PURPOSE: To evaluate helical computed tomography (CT) in the preoperative assessment of crossing arteries in kidneys with ureteropelvic junction (UPJ) obstruction and to compare the results with those obtained by means of angiography. MATERIALS AND METHODS: Forty-one consecutive patients with symptomatic UPJ obstruction in 42 obstructed kidneys underwent renal helical CT and renal intraarterial digital subtraction angiography (DSA; flush aortography and bilateral selective renal injections). The helical CT and DSA images were interpreted in a blinded manner by two readers, and the results were compared. RESULTS: DSA showed 126 renal arteries in the 41 patients; 56% of patients had supernumerary renal arteries. Helical CT depicted 121 (96%) of these 126 renal arteries prospectively. Retrospectively, 124 (98%) renal arteries were visible on CT images. Twelve (29%) of the 42 kidneys with UPJ obstruction had identifiable arteries crossing the UPJ on DSA images. If DSA is used as the standard of reference, CT angiography was 100% sensitive and 96.6% specific for depicting these crossing arteries. CONCLUSION: Renal helical CT seems suitable to replace intraarterial DSA in the preoperative assessment of crossing arteries in kidneys with UPJ obstruction.     

64层螺旋CT血管成像诊断脊髓血管畸形的价值

目的 探讨64层螺旋CT 血管成像(CTA)对脊髓血管畸形的诊断价值.方法 经临床和MR检查拟诊为脊髓血管畸形的15例患者进行了CTA.所有患者均在1周内进行了DSA检查.其中4例行于术治疗.将CTA图像与DSA和手术所见进行对照,从判定畸形的类型、显示病变累及的范围、供血动脉、引流静脉和可能存在的瘘口等方面,对CTA图像进行评价.结果 15例脊髓血管畸形经DSA和手术确诊,分别为6例髓内动静脉畸彤、2例髓周动静脉瘘、3例硬脊膜动静脉瘘和4例Cobb综合征.CTA对15例患者的分类和对病变累及范围的判断与DSA结果一致.CTA清晰显示了病变的主要供血动脉和引流静脉.5例动静脉瘘中4例CTA判断的瘘口位置与DSA所见一敛,另1例为复杂血管畸形,瘘口难以辨别.CTA还清晰显示了4例Cobb综合征位于椎旁和皮下的畸形血管团.结论 64层螺旋CTA可以判定脊髓血管畸形的类型,快速、无创地显示其主要病变特征,可作为该病的筛查手段.     

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.     

64层螺旋CT脑血管造影在颅内动脉瘤诊断中的应用

目的:与DSA相对照,探讨64层螺旋CT脑血管造影在颅内动脉瘤中的诊断价值。方法:对29例临床怀疑颅内动脉瘤的患者行64层螺旋CT脑血管造影(CTA)和DSA检查,使用GE64层Lightspeed VCT获得原始图像,所有病例均采用多层面重建(multiplanar reconstruction,MPR)、容积再现(volume rendering,VR)、薄层块最大密度投影(thin-slab maximumintensity projectjon,TS MIP)。后处理图像及DSA图像由2位放射科医生共同评估。结果:29例患者中,DSA证实25例共27个动脉瘤,其中2例为2个动脉瘤。与DSA结果相对照,CTA共检出25例26个动脉瘤,漏诊了1个颈出动脉瘤。CTA清晰显示了动脉瘤的形态、大小及载瘤动脉,3例动脉瘤瘤颈DSA未显示,CTA显示了全部动脉瘤的瘤颈。结论:64层CTA在颅内动脉瘤的诊断中具有极高价值,特别在显示动脉瘤瘤颈方面具有独特的优势,对临床治疗具有指导意义。     

Comparison of 2D and 3D digital subtraction angiography in evaluation of intracranial aneurysms

BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) is considered the criterion standard for depiction of intracranial aneurysms, it is often difficult to determine the relationship of overlapping vessels to aneurysms when using 2D DSA. We compared 2D and 3D DSA in evaluation of intracranial aneurysms. METHODS: Thirty-six consecutive patients with cerebral aneurysms underwent 2D and 3D DSA. After standard 2D DSA, rotational DSA was performed. Maximum intensity projection (MIP) and shaded surface display (SSD) images were created from the rotational DSA data sets. All images were assessed randomly for overall image quality, presence of aneurysm, presence of aneurysmal lobulation, visualization of aneurysmal neck, and relationship to adjacent vessels. Data analysis was conducted for 40 aneurysms treated by clip placement. RESULTS: One aneurysm that was not detected at 2D DSA was classified as uncertain on the basis of rotational DSA. All aneurysms were classified as probably or definitively present on the basis of MIP and SSD findings. Overall image quality of rotational DSA, MIP, and SSD was statistically inferior to that of the standard 2D DSA for visualization of distal arteries. However, MIP and SSD images were significantly superior to those of standard 2D DSA for all other evaluations. For detection of lobulation, SSD images were significantly superior to other images, and for visualization of aneurysmal neck and relationship to neighboring arteries, SSD images were significantly superior to those of rotational DSA. For evaluation of the relationship to neighboring arteries, MIP images were significantly superior to those of rotational DSA. CONCLUSION: Three-dimensional DSA, especially SSD, provided more detailed information for evaluating cerebral aneurysms than did standard 2D and rotational DSA.     

Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis

Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiography (MRA) for the diagnosis of RAS. Sixty-two patients with secondary hypertension were enrolled in the study. All patients had conventional renal angiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 °, field of view 36 × 36 cm, matrix 246 × 256, 1 excitation). Gadolinium 0.3 mmol/kg was administered and 60 1.5-mm-thick partitions were obtained over a duration of 3.5 min. The MRA images were then compared with conventional digital subtraction angiography (DSA) images. Conventional DSA demonstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93 %). Twenty-one renal artery stenoses and four occluded arteries were seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98 %, accuracy of 96 %, positive predictive value of 92 % and negative predictive value of 97 % when compared with conventional DSA. Gadolinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries. Received: 17 March 1998; Revision received: 30 June 1998; Accepted: 28 August 1998     

Evaluation of dynamic gadolinium-enhanced breath-hold MR angiography in the diagnosis of renal artery stenosis.

OBJECTIVE: The aim of our study was to evaluate a three-dimensional gadolinium-enhanced breath-hold MR angiography sequence using standard MR gradients in detecting renal artery stenosis. SUBJECTS AND METHODS: Forty-two patients referred for angiography for suspected renal artery stenosis underwent both conventional digital subtraction angiography (DSA) and MR angiography. MR angiography was performed on a 1.5-T scanner with standard gradients. A fast multiplanar spoiled gradient-echo sequence was used with the following parameters: TR/TE, 10.3/1.9; flip angle, 45 degrees; field of view, 36 x 32 cm; matrix size, 256 x 128; one excitation; volume thickness, 70 mm; and partitions, 28. Gadolinium was administered IV as a dynamic bolus of 30-40 ml. Conventional and MR angiographic images were interpreted by two radiologists in consensus. RESULTS: DSA revealed 87 renal arteries, of which 79 were in 35 patients with native kidneys and eight arteries were in seven patients with transplanted kidneys. Gadolinium-enhanced MR angiography showed 85 (98%) of 87 renal arteries. Seventeen patients had 20 significant (>50% stenosis) renal artery stenoses and five patients had five occluded renal arteries revealed by DSA. MR angiography revealed 85 renal arteries (98%), 20 stenoses (100%), and five occlusions (100%). Gadolinium-enhanced MR angiography led to one false-positive interpretation for renal artery stenosis and no false-negative interpretations. Thus, the sensitivity, specificity, and accuracy of MR angiography for renal artery stenosis were 100%, 98%, and 99%, respectively. CONCLUSION: The MR angiography pulse sequence we used was an effective and reliable technique for the diagnosis of renal artery stenosis. The sequence can be performed on widely available MR equipment that does not require fast gradient hardware.     

MSCTA诊断下肢动脉闭塞性疾病

目的：探讨16层螺旋CT对下肢动脉闭塞性疾病的诊断价值。方法：对40例临床可疑外周动脉闭塞性疾病的患者行下肢动脉16层螺旋CT血管成像,其中30例患者于CTA检查前或后两周内行DSA检查,以DSA为金标准,评价CTA诊断的准确性。结果：CTA诊断下肢动脉狭窄（≥50%）的敏感度为95.56%（129/135）,特异度为98.20%（545/555）,符合率97.68%（674/690）,阳性预测值98.88%（176/178）,阴性预测值99.61%（512/514）。结论：16层螺旋CT对诊断下肢动脉闭塞性疾病有较高的敏感性、特异性和准确性,可部分替代DSA检查。     

Multidetector–row CT angiography of renal artery stenosis in 50 consecutive patients: prospective interobserver comparison with DSA

PURPOSE: The purpose of this study was to establish the diagnostic value of multidetector-row computed tomography (MDCT) angiography compared with digital subtraction angiography (DSA) for detection and quantification of both main and accessory renal artery stenosis in patients with secondary hypertension. MATERIALS AND METHODS: Fifty consecutive patients scheduled for DSA were considered candidates for MDCT angiography. In all patients, MDCT angiography of the abdominal aorta was performed before DSA. For the purpose of interpretation, the arteries were separately interpreted either with DSA or MDCT angiography in order to provide qualitative and quantitative information. For qualitative evaluation, one experienced reader graded the opacification of renal arteries as excellent, good or poor; for quantitative evaluation, MDCT and DSA were independently evaluated for the number of renal arteries and the presence, location and degree of stenosis in random order by three readers. On the basis of consensus readings, calculations of sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for detection of degree of stenosis were made by using DSA findings as the standard of reference. Interobserver variability was also assessed. RESULTS: With regard to qualitative analysis, arterial enhancement was considered excellent in 39 patients and good in 11. For quantitative analysis, 73 arteries were classified as normal with DSA. Although 72 of these were also classified as normal with CT angiography, one was overestimated by one grade; at DSA, 16 arteries were classified as moderately stenotic; in two arteries, there was an overestimation of one grade. Perfect correlation was achieved for the diagnosis of occlusion. In two patients, all three readers detected multiple severe stenoses on both modalities, with a "string-of-beads" appearance typical of fibromuscular dysplasia. Accessory arteries were correctly identified as such by all three readers on either DSA or MDCT. Levels of sensitivity, specificity and accuracy regarding degree of stenosis were 100%, 98.6% and 96.9%, respectively, with PPV and NPV of 97.6% and 100%, respectively. When we considered significant arterial stenosis (50%-100% luminal narrowing), sensitivity, specificity and accuracy were 100%, 97.3% and 97.8%, respectively, with a PPV and NPV of 98.2% and 97.8%, respectively. For all observers, interobserver agreement was almost perfect (k=0.81-1) for both MDCT and DSA, with a k value between 0.82 and 0.95. CONCLUSIONS: MDCT angiography is very accurate and robust, even for the assessment of renal artery stenosis, and has the potential to become a viable substitute, in most cases, for diagnostic catheter-based DSA.     

Echo-enhanced transcranial color-coded duplex sonography in the diagnosis of cerebrovascular events: a validation study

BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography (TCCD) is a diagnostic technique for evaluation of intracranial arteries in patients with acute stroke. Echo-enhancing contrast agents (EEAs) are necessary to visualize intracranial vessels in up to 30% of patients because of limited acoustic bone windows. In this study, we assessed the diagnostic efficacy of echo-enhanced TCCD (eTCCD) in correlation with the gold standard, digital subtraction angiography (DSA). METHODS: We prospectively evaluated all patients with eTCCD who subsequently underwent DSA for evaluation of cerebrovascular symptoms over a 24-month period. We administered Levovist as an EEA. Two blinded reviewers analyzed all eTCCD findings and correlated them with DSA. RESULTS: We included 132 consecutive patients (40 women, 92 men; mean age, 58 +/- 14 years) with 164 datasets: 24/164 had normal findings, 98/164 had abnormalities of extracranial carotid arteries, 32/164 had abnormalities of intracranial arteries, and 21/164 had abnormalities in vertebrobasilar circulation as determined by DSA. For eTCCD, we found a sensitivity of 82% (95% confidence interval [CI]: 75%-90%), a specificity of 98% (95% CI: 90%-100%), a positive predictive value of 99% (95% CI: 94%-100%), and a negative predictive value of 75% (95% CI: 64%-85%); 7/164 (4%) examinations were inconclusive because of insufficient bone windows. The interobserver agreement was almost perfect (kappa value, 0.92; 95% CI: 0.87-0.97). CONCLUSION: eTCCD provides high diagnostic validity for the status of the major intracranial arteries. In particular, a normal vessel status reliably assessed by an experienced sonographer could supersede further imaging procedures. In patients with acute ischemic stroke not eligible for established angiographic techniques, eTCCD may be useful as an alternative imaging technique.