128层螺旋CT血管成像对头颈部血管病变的临床诊断价值探析

目的：探讨128层螺旋 CT 血管成像（MSCTA）对头颈部血管病变的临床诊断价值。方法选取我院接收的30例临床怀疑或确诊为头颈部血管病变患者作为本次的研究对象,30例患者均行128层螺旋 CT 血管造影检查,并采用多平面重建（MPR）、曲面重建（CPR）、容积重建（VR）、最大密度投影（MIP）显示血管,对128层螺旋 CT 血管成像在头颈部血管性病变中的应用价值进行评价。结果本组30例患者中8例患者行头颅 CTA 检查,其中6例患者为先天性血管发育异常,22例患者行头颈部 CTA 检查,其中14例患者发育异常,17例患者显示颈动脉系统粥样硬化。结论128层螺旋 CT 血管成像具有无创、准确性高、快速、安全性高等多种优点,在头颈部血管性病变的诊断中有较高的应用价值,可推广应用。     

Usefulness of computed tomography angiography for the detection of high-risk aortas for carotid artery stenting

This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery.     

多层螺旋CT血管成像诊断颈动脉海绵窦瘘

目的探讨颈动脉海绵窦瘘(CCF)的解剖病理基础及螺旋CT血管成像(MSCTA)表现,提高MSCTA对CCF的诊断能力。方法12例经DSA证实的CCF均进行了螺旋CT平扫、增强扫描及血管成像重建。结果CCF的MSCT及CTA表现为:海绵窦扩大及眼上静脉扩张12例,并与颈内动脉同时显影;其他属支静脉扩张6例;对侧海绵窦扩大4例,与DSA检查结果一致。患侧眼球突出12例。颅底、眶壁骨折5例。眼球壁模糊、增厚5例。脑挫伤、出血4例。眼外肌增粗1例。结论螺旋CT及其血管成像诊断CCF简单、快捷、准确、可靠,特别是在外伤性CCF中,是首选的检查及诊断方法。     

167例缺血性脑血管病的多层螺旋CT血管造影分析

目的探讨MSCTA诊断缺血性脑血管病（ICVD）的临床价值。方法回顾性分析并对比167例临床确诊ICVD患者的头颈部MSCTA及DSA表现。结果头颈部MSCTA发现123例患者动脉狭窄,15例单纯前循环动脉狭窄,41例单纯后循环动脉狭窄,67例前、后循环动脉均有狭窄,多见于椎动脉（179／413,43．34％）、颈内动脉（217／539,40．26％）和大脑中动脉（135／539,25．05％）,99例共641支动脉存在硬化斑块。以DSA为金标准,MSCTA诊断头颈动脉狭窄的敏感度为97．54％（119／122）,特异度为91．11％（41／45）。结论MSCTA可准确评价头颈部动脉狭窄,在判断ICVD病因方面具有优势。     

多层螺旋CT血管成像在烟雾病诊断中的应用

目的探讨多层螺旋CT血管成像（MSCTA）在烟雾病诊断中的价值以及应用前景。方法回顾性分析10例烟雾病患者的MSCTA及数字减影血管造影（DSA）的影像学资料。结果MSCTA可清晰显示狭窄、闭塞以及异常增多的脑血管。容积重建有利于显示病变血管与周围结构的空间关系,综合最大密度投影法重建和多曲面重建图像分析可清晰显示异常增多的脑血管,即烟雾状血管。MSCTA对狭窄及闭塞血管的检出率为66．2％（53/80）;DSA对狭窄及闭塞血管的检出率为67．5％（54／80）,两者比较差异无统计学意义（P〉0．05）。MSCTA对颅底异常血管网的显示及分布情况与DSA大致相似。结论MSCTA诊断烟雾病的灵敏度高,是早期诊断烟雾病的重要依据,早期诊断、及时治疗是改善烟雾病患者预后的有效方法。     

Multislice computerized tomography angiography in the evaluation of intracranial aneurysms: a comparison with intraarterial digital subtraction angiography

OBJECT: The goal of this study was to assess the diagnostic accuracy of computerized tomography (CT) angiography performed with the aid of multislice technology (MSCT angiography) in the investigation of intracranial aneurysms, by comparing this method with intraarterial digital subtraction (IADS) angiography. METHODS: Fifty consecutive adult patients, who successively underwent MSCT angiography (four rows) and IADS angiography of intracranial vessels, were prospectively identified. The MSCT angiography studies consisted of 1.25-mm slices, with 0.8-mm reconstruction intervals, a pitch of 0.75, and timing determined by a test bolus. Two neuroradiologists, who were blinded to the initial interpretation of the MSCT angiograms as well as to those of the IADS angiograms, independently reviewed the MSCT angiograms for the detection and characterization of intracranial aneurysms. Forty-nine intracranial aneurysms were identified in 40 patients; 33 of these lesions were responsible for subarachnoid hemorrhage. The sensitivity, specificity, and accuracy of MSCT angiography in the detection of intracranial aneurysms were 94.8, 95.2, and 94.9%, respectively, on a per-aneurysm basis and 99, 95.2, and 98.3%, respectively, on a per-patient basis. Interobserver agreement was 98%. There was an excellent correlation between aneurysm size assessed using MSCT angiography and that determined by IADS angiography (slope = 0.916, r = 0.877, p < 0.001); however, 2 mm stood as the cutoff size below which the sensitivity of MSCT angiography was statistically lower. That method displayed great accuracy in characterizing the morphological characteristics of the aneurysm. CONCLUSIONS: Multislice CT angiography is an accurate and robust noninvasive screening test for intracranial aneurysms. It performs better than that reported for single-slice CT angiography. Introduction of eight- and especially 16-row MSCT angiography will provide further progression through thinner slices, a lower pitch, and a purely arterial phase.     

CT angiography of the carotid arteries in trauma to the neck.

OBJECTIVES: serious vascular injuries to the neck may be asymptomatic or masked by other life-threatening conditions. Angiography, the "gold standard" vascular imaging modality, is an invasive procedure. Moreover, it is time-consuming and thus may delay a needed vascular intervention. The results of screening angiography are negative in more than 80% of cases. Therefore other less invasive and faster screening tests, such as the Doppler ultrasound and magnetic resonance angiography, have been tested. This retrospective study was done to evaluate the use of CT angiography (CTA) in suspected vascular injuries of the neck. METHODS: from 1995 to 1998, 16 patients with suspected traumatic carotid artery injury underwent CTA. Twelve of these patients had penetrating injuries and four had blunt injuries to the neck. CTAs were obtained by Elscint Twin Flash Spiral Scanner, while MIP reconstructions were carried out on an Omnipro, Elscint (Indy, Silicon Graphics) work station and interpreted by a radiologist. RESULTS: all the CTAs were diagnostic. Positive findings included one complete tear of the right common carotid artery (confirmed by surgery) due to a penetrating injury and one bilateral internal carotid artery thrombosis after blunt injury to the neck. In addition, three patients with multiple trauma were operated on, due to either proximity only or questionable neurological findings. Surgical exploration confirmed the negative findings seen on CTA. CONCLUSION: CT angiography of the carotid arteries in cervical trauma may be used as an accurate decisive tool for a needed surgical intervention. More studies with larger number of patients and comparison with angiography are needed.     

Three-dimensional helical computerized tomography angiography in the diagnosis,characterization, and management of middle cerebral artery aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: Middle cerebral artery (MCA) aneurysms can be difficult to detect and characterize. The authors describe the utility and impact of helical computerized tomography (CT) angiography for the evaluation of aneurysms in this location, and compare this modality with digital subtraction (DS) angiography and intraoperative findings. METHODS: Two hundred fifty-one patients with suspected cerebral aneurysms underwent CT angiography. Two-dimensional multiplanar reformatted images and three-dimensional CT angiograms were examined by two independent readers in a blinded fashion. Results were compared with findings on DS angiograms to determine the relative efficacy of these modalities in the detection and characterization of aneurysms. Questionnaires completed by neurosurgeons and endovascular therapists were used to determine the impact of CT angiograms on aneurysm management. Twenty-eight patients harboring 31 MCA aneurysms and 26 patients without aneurysms were identified using CT angiography. The sensitivity of CT angiography and DS angiography for MCA aneurysms was 97%; both techniques showed 100% specificity. In 76% of evaluations, the CT angiography studies provided information not available on DS angiography examinations. For the characterization of aneurysms, CT angiography was rated superior (72%) or equal (20%) to DS angiography in 92% of cases evaluated (p < 0.001). Computerized tomography angiography was evaluated as the only study needed for patient triage in 82% of cases (p < 0.001), and as the only study needed for treatment planning in 89% of surgically treated (p < 0.001) and in 63% of endovascularly treated cases (p < 0.001). The information acquired on CT angiograms changed the initial treatment plan in 24 (67%) of these 36 complex lesions (p < 0.01). The aneurysm appearance intraoperatively was identical or nearly identical to that seen on CT angiograms in 17 (89%) of 19 of the surgically treated cases. CONCLUSIONS: Computerized tomography angiography has unique advantages over DS angiography and is a viable alternative to the latter modality in the diagnosis, triage, and treatment planning in patients with MCA aneurysms.     

CT angiography in complex upper extremity reconstruction

Computed tomography angiography is a new technique that provides high-resolution, three-dimensional vascular imaging as well as excellent bone and soft tissue spatial relationships. The purpose of this study was to examine the use of computed tomography angiography in planning upper extremity reconstruction. Seventeen computed tomography angiograms were obtained in 14 patients over a 20-month period. All studies were obtained on an outpatient basis with contrast administered through a peripheral vein. All the studies demonstrated the pertinent anatomy and the intraoperative findings were as demonstrated in all cases. Information from two studies significantly altered pre-operative planning. The average charge for computed tomography angiography was 1,140 dollars, compared to 3,900 dollars for traditional angiography.     

多层螺旋CTA对肝脏肿瘤介入化疗及栓塞治疗的指导意义

目的探讨多层螺旋CTA在肝脏肿瘤介入化疗及栓塞治疗中的应用价值。方法对32例肝脏肿瘤患者行MSCTA检查,再行肝脏动脉DSA造影并介入化疗及栓塞治疗。结果以DSA造影作为标准进行比较,MSCTA检出变异动脉10例,准确率为100%,肿瘤明确供血动脉30例,准确率为93.75%。显示肿瘤染色24例,异常肿瘤血管20例,门静脉癌栓7例,动静脉短路4例,与DSA造影所见具有高度的一致性,且对门静脉显影及癌栓的显示优于DSA。结论MSCTA能准确显示变异血管、肿瘤的肝外供血动脉,有无门静脉受累及受累程度,对肝脏肿瘤的介入化疗及栓塞治疗有重要的指导意义。     

Comparison of multislice computerized tomography angiography and digital subtraction angiography in the postoperative evaluation of patients with clipped aneurysms

OBJECT: In this study the accuracy of multislice computerized tomography (MSCT) angiography in the postoperative examination of clip-occluded intracranial aneurysms was compared with that of intraarterial digital subtraction (DS) angiography METHODS: Forty-nine consecutive patients with 60 clipped aneurysms (41 of which had ruptured) were studied with the aid of postoperative MSCT and DS angiography. Both types of radiological studies were reviewed independently by two observers to assess the quality of the images, the artifacts left by the clips, the completeness of aneurysm occlusion, the patency of the parent vessel, and the duration and cost of the examination. The quality of MSCT angiography was good in 42 patients (86%). Poor-quality MSCT angiograms (14%) were a result of the late acquisition of images in three patients and the presence of clip or motion artifacts in four. Occlusion of the aneurysm on good-quality MSCT angiograms was confirmed in all but two patients in whom a small (2-mm) remnant was confirmed on DS angiograms. In one patient, occlusion of a parent vessel was seen on DS angiograms but missed on MSCT angiograms. The sensitivity and specificity for detecting neck remnants on MSCT angiography were both 100%, and the sensitivity and specificity for evaluating vessel patency were 80 and 100%, respectively (95% confidence interval 29.2-100%). Interobserver agreements were 0.765 and 0.86, respectively. The mean duration of the examination was 13 minutes for MSCT angiography and 75 minutes for DS angiography (p < 0.05). Multislice CT angiography was highly cost effective (p < 0.01). CONCLUSIONS: Current-generation MSCT angiography is an accurate noninvasive tool used for assessment of clipped aneurysms in the anterior circulation. Its high sensitivity and low cost warrant its use for postoperative routine control examinations following clip placement on an aneurysm. Digital subtraction angiography must be performed if the interpretation of MSCT angiograms is doubtful or if the aneurysm is located in the posterior circulation.     

MSCTCTA与DSA诊断肾癌的应用对照研究

目的探讨多层螺旋CT血管成像（MSCTA）与选择性肾动脉数字减影血管造影（DSA）对诊断肾癌的应用价值。方法对26例病理证实的肾癌患者的MSCTA与选择性肾动脉DSA影像特征进行对照分析。结果MSCTA对肾癌的肿瘤血供类型、肿瘤供血动脉来源的诊断符合率和肾动脉解剖显示正确率达到96．15％。选择性肾动脉DSA对肾癌的肿瘤血供类型、肿瘤供血动脉来源的诊断合率和肾动脉解剖显示正确率达到92．31％（P〉0．05）。结论MSCT（CTA）与DSA对诊断肾癌都具有较高的临床诊断价值；对指导肾癌的介入与外科手术治疗，MSCTA具有更高的实用价值。     

Sixteen-row multislice computed tomography angiography in the diagnosis and characterization of intracranial aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: The goal of this study was to prospectively compare the effectiveness of 16-slice computed tomography (CT) angiography with that of conventional digital subtraction (DS) angiography and the surgical findings used to detect and characterize intracranial aneurysms. METHODS: Two hundred forty-four consecutive patients underwent both CT angiography and DS angiography no more than 3 days apart. Computed tomography angiography was performed with a 16-row multislice CT scanner in which a collimation of 0.75 mm was used. Two observers independently reviewed the CT images, and 1 of the 3 attending neuroradiologists reviewed the DS angiograms. They determined the presence, location, quantitation, and characterization of the intracranial aneurysms. Statistical results were calculated independently for the image interpretation performed by the 2 CT scan readers and the DS angiogram reader by using the combination of DS angiography or intraoperative findings or both as a reference standard. RESULTS: One hundred thirty-six patients harboring 153 intracranial aneurysms were included in this series. There was no statistically significant difference in sensitivity between 16-slice CT angiography and conventional DS angiography (p > 0.05). The sensitivities of 16-slice CT angiography for aneurysms < 5 mm, 5-10 mm, and > 10 mm were 94.8, 100, and 100%, respectively, on a per-aneurysm basis. The overall sensitivity and specificity of CT angiography for aneurysms were 98.0 and 99.1%, respectively. Sixteen-slice CT angiograms were clearer and more accurate in depicting the relationship of aneurysms to bone structures and adjacent branch vessels. CONCLUSIONS: Computed tomography angiography using a 16-slice scanner is an accurate tool for detecting and characterizing intracranial aneurysms, including small aneurysms. Noninvasive 16-slice CT angiography will become a viable replacement for conventional DS angiography in the diagnosis and characterization of aneurysms.     

Arterial assessment before carotid endarterectomy: current practice in Great Britain and Ireland

A survey of the management of patients with putative carotid artery disease by 245 vascular and neurosurgeons in Great Britain and Ireland was conducted with a 96 per cent response. Ninety-six (41%) surgeons performed at least one carotid endarterectomy in 1984 and a total of 1374 such operations were carried out in that year. Of the 40 surgeons who performed more than ten operations in 1984, 95 per cent generally employed a screening technique which was less invasive than conventional angiography in their management. Techniques based on ultrasonography were more popular than those based on digital subtraction angiography (DSA) in this respect. If carotid endarterectomy were to be undertaken, 63 per cent of surgeons required pre-operative conventional angiograms. Of the 38 per cent who did not routinely use conventional angiography, all but one used digital subtraction angiography. Ultrasonography and DSA have had a significant impact on the management of carotid artery disease in Great Britain and Ireland and their individual places in such management are becoming clear.     

Three-dimensional computerized tomography angiography in the diagnosis of cerebrovascular disease.

Computer-generated three-dimensional reconstruction of the intracranial vascular system obtained by contrast-enhanced computerized tomography (CT) has been used in the diagnosis of 20 patients with known or suspected intracranial cerebrovascular disease. This technique allows visualization of the intracranial vasculature without exposing patients to the risks associated with intra-arterial angiography. The color prints and videotape images generated have been used to diagnose the presence of intracranial aneurysms, arteriovenous malformations, and venous angiomas. They have also been used to rule out structural abnormalities in patients with suspected intracranial vascular pathology and to screen patients with a strong family history of intracranial aneurysm. In 11 patients who underwent both three-dimensional CT angiography and intra-arterial angiography, the diagnostic correlation was 100%. No complications from the procedures or from incorrect diagnosis have been encountered. Although this technique requires further development and clinical evaluation, the authors' early experience with three-dimensional CT angiography suggests that this may become a valuable tool in the diagnosis of patients with cerebrovascular disease.     

Computerized tomography angiography in patients with subarachnoid hemorrhage: from aneurysm detection to treatment without conventional angiography.

OBJECT: The purpose of this study was to determine prospectively whether and to what extent computerized tomography (CT) angiography can serve as the sole imaging method for a preoperative workup in patients with ruptured intracranial aneurysms. METHODS: During a 1-year period, all patients who presented to the authors' hospital with subarachnoid hemorrhage demonstrated by unenhanced CT scanning or lumbar puncture underwent CT angiography. Two radiologists evaluated the CT angiography source images and maximum intensity projection slabs and arrived at a consensus. They categorized the quality of the CT angiography as adequate or inadequate and classified aneurysms that were detected as definitely or possibly present. The parent artery of anterior communicating artery aneurysms was identified by asymmetrical anterior cerebral artery size and asymmetrical aneurysm location. The parent artery was indicated by the larger A1 segment in cases of asymmetrical A1 size. Only CT angiograms of adequate quality that revealed aneurysms classified as definitely present and with an unequivocal parent artery were presented to the neurosurgeons, who decided whether preoperative digital subtraction (DS) angiography should still be performed. Forty-nine of the 100 studied patients did not undergo surgery because of poor clinical condition, nonaneurysmal cause of the hemorrhage, or endovascular treatment of the ruptured aneurysm. Of the 51 patients who underwent surgery, radiologists required DS angiography in 17 patients; the imaging technique provided greater certainty in 13 instances. The neurosurgeons required DS angiography 11 times; this provided additional information in two instances. Twenty-three (45%) of the 51 patients were surgically treated successfully on the basis of CT angiography findings alone. CONCLUSIONS: Computerized tomography angiography can replace DS angiography as the preoperative neuroimaging technique in a substantial proportion of patients with ruptured intracranial aneurysms.     

Three‐dimensional multislice spiral computed tomographic angiography: A potentially useful tool for safer free tissue transfer to complicated regions

Three‐dimensional multislice spiral computed tomographic angiography (3D‐MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer to complicated regions. 3D‐MSCTA was performed preoperatively in 26 patients scheduled for free tissue transfer, in whom the availability of the recipient vessels were considered to be uncertain, and 23 of these were operated on. Radiographic and operative findings regarding the availability of the recipient vessels for anastomosis were correlated in 21 of these 23 patients. 3D‐MSCTA yielded two false‐positive results; anastomosis was not possible because of widespread atherosclerotic plaques and poor flow observed in the recipient arteries despite the good caliber observed in 3D‐MSCTA images. 3D‐MSCTA provides a noninvasive means of preoperatively assessing recipient site vessels for anatomic variations and suitability before free tissue transfer and enables the surgeon to establish an appropriate treatment plan. But it is not 100% reliable yet and the possibility of false‐positive results should be kept in mind, especially inthe patients with peripheral vascular disease. 3D‐MSCTA has the potential to replace digital subtraction angiography for planning of microvascular reconstructions and newer devices with higher resolutions will probably increase the reliability of this technique. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.     

Carotid surgery without angiography is possible and safe

BACKGROUND: To evaluate the possibility to perform carotid surgery without angiography. METHODS: From January 1994 to June 1998, 514 patients with carotid obstructive disease were operated upon, 225 of them (43.8%) without previous angiography; 55 out of 68 (80.8%) during the last six months. Eighty-one (36.0%) had lateralizing symptoms, 50 aspecific ones (22.2%) and 94 were asymptomatic (41.8%). All patients were investigated by color-coded duplex sonography (CDS) of the arteries at the neck and by transcranial Doppler (TCD) and computed tomography (CT). One hundred eighty-eight patients were operated upon under local anaesthesia and 37 under general anesthesia; 204 had a carotid endartereotomy (90.7%) with patch angioplasty in 154 (75.5%), and 21 required a bypass graft (9.3%). In 26 patients (11.5%) an indwelling shunt was needed. RESULTS: Findings at surgery were consistent with CDS for plaque composition, ulcerations and degree of stenosis. There were no early deaths. Neurologic or ocular deficits occurred in 2 cases (0.9%). No strokes were observed in follow-up from 6 to 34 months. CONCLUSIONS: Carotid endarterectomy can be done without angiography in selected cases provided CDS plus TCD are of high quality. Under such conditions it can be considered a safer way to deal with carotid obstructive disease.     

Surgical anatomy of the cerebral arteries in patients with subarachnoid hemorrhage: comparison of computerized tomography angiography and digital subtraction angiography.

OBJECT: The purpose of this study was to compare computerized tomography (CT) angiography and digital subtraction (DS) angiography studies in patients with subarachnoid hemorrhage (SAH) to assess their vascular anatomy relevant to cerebral aneurysm surgery. METHODS: From a prospective series of 100 patients with SAH, the authors selected 73 patients whose CT angiography studies were of adequate quality and in whom DS angiography of both carotid arteries had been performed. Eleven patients with no DS angiographic studies of the vertebrobasilar artery were only evaluated for the anterior half of the circle of Willis. Anterior communicating arteries (ACoAs), both precommunicating anterior cerebral arteries (A1 segments), both posterior communicating arteries (PCoAs), and both precommunicating posterior cerebral arteries (P1 segments) were assessed on CT angiography and DS angiography by two independent observers. CONCLUSIONS: Computerized tomography angiography compares well with DS angiography for visualizing normal-sized arteries, and is superior for visualizing ACoAs and hypoplastic A1 and P, segments. Important preoperative aspects such as dominant A1 segments and PCoAs are equally well seen using either modality. Neither method enabled the authors to visualize more than 50% of PCoAs. Use of CT angiography can provide the required preoperative anatomical information for aneurysm surgery in most patients with SAH.     

Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms

OBJECT: The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed. METHODS: Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated. In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied. CONCLUSIONS: Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.