Microsurgical management of cerebral aneurysms based in CT angiography with three-dimensional reconstruction (3D-CTA) and without preoperative cerebral angiography

Summary  Objective. To study the posibilities of the microsurgical management of ruptured intracranial aneurysms with the sole preoperative information provided by computed tomography angiography with three-dimensional reconstruction (3D-CTA).  Methods. Patients were studied with 3D-CTA after diagnosis of subarachnoid hemorrhage. If the study had an adequate quality and revealed an aneurysm congruent with the clinical findings or neurological examination and/or with the location of the bleeding on computed tomography (CT) scan an early microsurgical clipping of the lesion was done. When the quality of the 3D-CTA study was not adequate or the quality being adequate displayed no lesions or the findings were not accurate enough to warrant direct microsurgical treatment, the patient was studied with cerebral digital substraction (DS) angiography. A total of 44 consecutive patients harbouring a total of 47 intracranial aneurysms diagnosed by 3D-CTA and without preoperative DS angiography were submitted to microsurgical clipping and included in the study.  Results. The overall mortality was 15.9% and the favourable results evaluated 6 months after discharge by means of the Glasgow Outcome Scale reached 70.4%. All lesions were successfully clipped. Surgery was done a mean of 4.1 days after the admission bleeding. A total of four microlesions undiagnosed by 3D-CTA were found at surgery and clipped. Postoperative DS angiography and necropsy findings were also used as control of the 3D-CTA findings but no additional information was provided excepting the finding in DS angiography of an asymptomatic intracavernous aneurysm. Therefore the sensitivity of the 3D-CTA for diagnosis of symtomatic aneurysms was 100% and the overall sensitivity 90.4%.  Conclusions. We have reached similar results in patients operated on with or without preoperative angiography. 3D-CTA provides very valuable anatomical information, which has an additional value in the microsurgical treatment of aneurysms of the anterior communicating artery complex. Finally, selected cases of ruptured intracranial aneurysms can be successfully managed with the preoperative information provided by 3D-CTA and without DS angiography.     

Utility of 320-detector row CT for diagnosis and therapeutic strategy for paraclinoid and intracavernous aneurysms

Background

The aim of this study was (1) to assess the diagnostic accuracy of 320-detector row computed tomography (CT) for paraclinoid and intracavernous aneurysms, and (2) to investigate whether this method provides sufficient information for surgery.

Methods

A total of 14 patients with 16 unruptured proximal ICA aneurysms underwent three-dimensional CT angiography (3D-CTA) fusion imaging, which was created by superimposing 3D-CT venography data and/or 3D-bone data onto 3D-CTA data using 320-detector row CT, magnetic resonance imaging (MRI), and 3D digital subtraction angiography (DSA). The images of each modality were assessed using intraoperative findings as the reference standard.

Results

All aneurysms were clearly visualized on 320-detector row CT. Bone subtraction and arterio-venous discrimination were accurate. On 3D-CTA fusion images, 11 aneurysms were diagnosed as “extracavernous” and five as “intracavernous”. No discordance in aneurysm location between the 3D-CTA fusion images and the intraoperative findings was found. In contrast, discordance between MRI and intraoperative findings were found in five of the 16 cases (31 %), which was significantly more frequent than with 3D-CTA (p?=?0.043). The findings DSA, which was performed in nine patients, were also in excellent agreement with the intraoperative findings. However, 3D-CTA fusion imaging provided more comprehensive information, including venous and osseous structures, than 3D-DSA. The 320-detector row CTA after surgery demonstrated a clear relationship between the clip and aneurysmal neck with notably few artifacts, which suggested the utility of this modality for postoperative assessment.

Conclusions

The 320-detector row CT provided high accuracy for the diagnosis of paraclinoid and intracavernous aneurysms. This technique also provided comprehensive depiction of the aneurysms and surrounding structures. Therefore, this modality might be useful for the diagnosis of the paraclinoid and intracavernous aneurysms and for developing a surgical treatment plan.     

The three-dimensional CT angiography findings of ruptured aneurysms hardly detectable by repeated cerebral angiography

We reported three cases of cerebral aneurysms hardly detectable by cerebral angiography, but easily detected by three-dimensional CT angiography (3D-CTA). These cases were ruptured aneurysms with subarachnoid hemorrhage. After detection of subarachnoid hemorrhage on CT scan, cerebral angiography was performed at first, but aneurysms were not detected. Subsequently 3D-CTA was carried out, and aneurysms were detected. In all cases, cerebral angiography was repeated, after the aneurysms had been found by 3D-CTA. This time aneurysms were all detected by cerebral angiography, but each case needed photographs from special direction. The aneurysms were small by usual cerebral angiography and they were almost invisible behind the artery near which they existed. 3D-CTA was very useful for detection of small aneurysms, but small perforating arteries around the aneurysms were invisible by 3D-CTA. To find these perforating arteries, cerebral angiography was needed.     

Perioperative evaluation of carotid endarterectomy by 3D-CT angiography with refined reconstruction: preliminary experience of CEA without conventional angiography

Three-dimensional CT angiography (3D-CTA) was employed for perioperative evaluation of carotid endarterectomy (CEA) as an alternative to conventional angiography. A total of 62 carotid arteries were examined before and after CEA, 26 with an early 3D-CT system and 36 with multidetector helical CT allowing sophisticated reconstruction by a personal workstation. In addition to patients who had undergone conventional angiography at other institutes, 10 subjects underwent CEA on the basis of 3D-CTA findings alone. The findings provided detailed information with an excellent view of carotid stenoses. Volume rendering images comprehensively visualized lesions and surrounding structures as well as calcifications, which were also well depicted by maximum intensity projection images. Evaluation of the cerebral circulation is one problem that still requires solution, although cerebral vessels were delineated by 3D-CTA. One patient experienced transient hemiparesis, but no significant permanent deficit. We conclude that 3D-CTA is a safe and accurate modality that is a practical alternative to conventional perioperative angiography.     

Can 3D-CTA Surpass DSA in Diagnosis of Cerebral Aneurysm?

Summary  After introducing of Helical scanning CT (HCT) and 3D-CTA (three-dimensional CT angiography), various improvements to these methods have been made every year to achieve better imaging quality. The current resolution permits visualisation of the internal structure of tumors, although as yet insufficiently clearly. We suggest that these improvements can be more efficient than conventional cerebral aneurysms angiography. In this study, we compared HCT and 3D-CTA with conventional cerebral angiography in patients with cerebral aneurysms at our facility. We also examined whether 3D-CTA has the possibility of independent clinical application and can surpass conventional DSA in diagnostic efficacy. In this paper, we found this information insufficient in clipping operations using 3D-CTA only when 1) It was difficult to distinguish a crooked infundibular dilation from an aneurysm, 2) Imaging threshold influenced the measured value of the vascular diameter and 3) It was also difficult to confirm whether the peripheral vessels adhere to the aneurysm. In conclusion, from the result of the comparison between 3D-CTA and DSA in this study, it was concluded that 3D-CTA is a reliable alternative method to conventional angiography in the diagnosis of anterior circulation and most aneurysms of regular size. In such cases it may be possible to obtain the same quality of preoperative information, but it is less invasive.     

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.     

Three-dimensional CT angiography for the surgical management of the vertebral artery-posterior inferior cerebellar artery aneurysms

Summary Background. Surgery of vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysms is not easy because there is a close anatomical relationship between aneurysms and the surrounding neurovascular structures, and bony structures in the lateral foramen magnum. The preoperative evaluation for a circumstantial comprehension of anatomical relationships is very important for the surgical treatment of the VA-PICA aneurysms. Our experience in using three-dimensional CT angiography (3D-CTA) for the surgical management of VA-PICA aneurysms is herein reported.Methods and findings. We successfully performed neck clipping in 5 cases of VA-PICA aneurysm using 3D-CTA. On 3D reconstructed images, we could see the characteristics of the aneurysms such as their relationships to the jugular tubercle and hypoglossal canal, the projecting direction of the dome, and the configuration of the neck in each case. 3D-CTA also provided a clear surgical view as well as the relationships of the aneurysms to the VA and origin of the PICA. Based on such information, we selected the most appropriate surgical approach among the transcondylar fossa approach, the transcondylar approach, or the far lateral approach with a C1 laminectomy.Conclusions. Since 3D-CTA demonstrates the surgical anatomy of VA-PICA aneurysms in detail, it is very useful for helping surgeons to select the optimal approach.     

The accuracy of CT scanning in the diagnosis of abdominal and thoracoabdominal aortic aneurysms

As CT scanning has evolved as a reliable clinical tool, the use of angiography in the diagnosis of aortic aneurysmal disease has diminished. Fewer than 25% of patients with aortic aneurysmal disease undergo aortic angiographic evaluation at our institution. A prospective clinical study was undertaken to assess the validity of this policy. One hundred patients with clinical or ultrasonographic evidence of aortic aneurysms were evaluated prospectively during the period July 1987 to December 1989. All patients underwent CT scanning as an initial evaluation. Patients were selected for angiography if they fulfilled any of the following criteria: radiographic evidence of thoracoabdominal or juxtarenal aneurysms, or horseshoe kidney; or clinical suggestion of renal artery stenosis, mesenteric arterial insufficiency, aortoiliac occlusive disease, or lower extremity aneurysmal disease. During this period 19 patients (19%) underwent both CT scanning and angiography. The indications for angiography were thoracoabdominal aneurysms (7), juxtarenal aneurysms (2), clinical evidence of mesenteric insufficiency (1) or renal insufficiency (2), evidence of lower extremity aneurysmal disease (3), or severe aortoiliac occlusive disease (4). Eighty-one patients (81%) underwent CT scanning as the only radiographic evaluation. No patient was adversely affected by elimination of angiographic evaluation. CT scanning revealed inflammatory aneurysms (4), retroaortic renal veins (2), and horseshoe kidney (1). This study suggests that most (81%) patients with aortic aneurysmal disease can be adequately evaluated by CT scanning, and that a very selective policy of angiographic evaluation is indicated.     

Improved identification of renal arteries in patients with aortic aneurysms by means of high-resolution computed tomography

Suprarenal extension of abdominal aortic aneurysms (AAAs) has been reported to be present in less than 10% of patients. Its preoperative demonstration is of value in planning the aneurysm repair; however, the most appropriate radiologic method of assessment remains controversial. Although many practitioners advocate angiography, recent advances in noninvasive techniques challenge this approach. To determine the optimal method of assessment, a retrospective study of CT, ultrasonography, and angiography was undertaken in a group of 101 patients with AAA. Conventional CT was used in all patients and high-resolution CT through the region of the renal vein was used in 45 of these patients. Ultrasonography was used in 27 patients and angiography in 23. Conventional CT detected the renal artery origins in 76% of the cases--results that improved to 98% when thin-section high-resolution CT was used. These improvements in CT make the delineation of the relationship of the renal arteries to the aortic aneurysms almost as accurate as angiography at approximately half the cost. Its accuracy, safety, and cost effectiveness make CT the modality of choice in the preoperative assessment of suprarenal aortic aneurysms.     

Efficacy of three dimensional CT angiography (3D-CTA) for a first diagnosis of occlusive cerebrovascular disorders]

Patients with cerebrovascular disorders generally undergo computerized tomography (CT), even though magnetic resonance imaging (MRI) is available. We investigated the efficacy of three dimensional CT angiography (3D-CTA) for a first diagnosis of occlusive cerebrovascular disorders. Sixty-two patients, who were suspected of occlusive cerebrovascular disorder on the basis of neurological findings or initial plain CT findings, were reviewed. 3D-CTA was performed at the first medical examination. As a result, two patients were diagnosed with ICA (internal carotid artery) occlusion, nine with MCA (middle cerebral artery) occlusion, and one with BA (basilar artery) occlusion. All twelve patients underwent cerebral angiography immediately after those 3D-CTA in every case. Angiographical findings were the same as 3D-CTA. Interventional superselective thrombolytic therapy was performed in ten of the twelve patients, and recanalization resulted in four of them. 3D-CTA may also be able to determine whether the occlusive vessel is the chief cerebral artery or the perforating artery.     

Paraplegia after endovascular repair of the thoracic and thoracoabdominal aorta

AIM: The aim of this study was to analyse the incidence and aetiology of paraplegia secondary to endovascular repair of the thoracic and thoracoabdominal aorta (TEVAR). METHODS: A retrospective study was conducted in the patients treated at our facility between March 1997 and April 2007. During this interval, 173 patients (163 men; median age: 62 years) underwent endovascular repair of the thoracic aorta. Indications for treatment were thoracic aortic aneurysms in 36 patients, thoracoabdominal aortic aneurysms in 33 patients, type B dissections in 43 patients, type A dissections in 5 patients, penetrating aortic ulcers in 31 patients, traumatic aortic transections in 9 patients, post-traumatic aortic aneurysms in 5 patients, aortobronchial fistulas in 8 patients, aortic patch ruptures in 2 patients, and an anastomotic aortic aneurysm in 1 patient. 101 procedures (58%) were conducted as emergency interventions while 72 were elective. Device design and implant strategy were chosen on the basis of an evaluation of morphology from a computed tomographic scan. Clinical assessment and imaging of the aorta (CT or magnetic resonance imaging) during follow up were performed prior to discharge, at 6 and 12 months, and then annually. RESULTS: A primary technical success was achieved in 170 patients (98%). The overall 30-day mortality rate was 9.2%. Length of follow-up ranged from 1 to 96 months, with a mean of 52 months. Paraplegia or paraparesis developed in 3 patients (1.7%). Two of these patients had a thoracoabdominal aortic aneurysm and the third a chronic expanding type B dissection, being treated with hybrid procedures. CONCLUSIONS: Endovascular repair of the thoracic and thoracoabdominal aorta is associated with a relatively low risk for postoperative paraplegia or paraparesis. Patients requiring long segment aortic coverage, and with prior aortic replacement are especially at risk.     

Existence of abdominal aortic aneurysms in patients with thoracic aortic dissections

OBJECTIVE: The objective of this study was to determine the coexistence or later development of pararenal and infrarenal abdominal aortic aneurysms (AAAs) in patients with thoracic aortic dissections. METHODS: One hundred forty-five patients (95 men, 50 women) encountered from 1992 to 2001 with thoracic aortic dissections-excluding those associated with trauma, those with Marfan's syndrome, and those with thoracoabdominal aortic aneurysms-were studied. The most common risk factors included hypertension (59%) and a history of tobacco use (52%). Type III dissections affected 86 patients (59%), and type I dissections affected the remaining 59 patients (41%). Aortic computed tomography (CT) scans were obtained annually. Data were assessed by univariate and multivariate analyses. RESULTS: Five patients (3%) had a history of AAA repair prior to their thoracic aortic dissection diagnosis-3 were type III dissections and 2 were type I dissections. Twelve patient's (8%) AAAs were diagnosed with the initial CT study of their thoracic aortic dissection. Type III dissections accounted for all but one of these (11 of 12, 92%). Ten additional AAAs (7%) developed in the 128 patients with no initial evidence of an AAA being recognized from 1 to 48 months (average 16 months) after the thoracic aortic dissection was diagnosed. Type III dissections affected 8 of these 10 patients. Among the total 27 AAAs noted in this series, 74% (20 AAAs) were not continuous with the thoracic aortic dissection. In the univariate analysis, age (P =.0002), male gender (P =.044), history of smoking (P =.01), chronic obstructive pulmonary disease (P <.001), duration of dissection (P =.05), and presence of type III dissection (P =.009) were associated with the presence of an AAA. In the multivariate analysis, both chronic obstructive pulmonary disease (odds ratio 5.4, 95% CI, 1.3 to 22.3; P =.02) and age (OR 1.06, 95% CI, 1.02 to 1.11; P =.004) were significant predictors of the development of AAAs. CONCLUSION: This study documented that patients with thoracic aortic dissections are at risk to harbor or develop a later AAA. This finding supports the tenet that abdominal CTs or ultrasound scanning should be mandatory in the follow-up of patients with known thoracic aortic dissections.     

Debatable questions in the surgical treatment of thoracic aortic aneurysms

Some controversies in the surgical approach to thoracic aortic aneurysms are discussed. The author recommends: to perform echocardiography in patients with aortic aneurysms for detection of intracardiac pathology which may complicate the postoperative course; to combine thoracic aortography with selective coronary angiography in patients with thoracic aortic aneurysm for diagnosis of coronary artery disease; to operate asymptomatic fusiform aneurysm that measure twice or more the size of the normal aorta; to resect and replace dissections of the ascending aorta during cardio-pulmonary bypass; and to use active shunts during resection of the descending and thoraco-abdominal aneurysm.     

CT动态血管成像术前评估脑膜瘤

目的探讨基于CT动态血管成像的4D-CTA对术前评估脑膜瘤的价值。方法对34例颅内脑膜瘤患者行颅脑CT动态容积扫描。分别对图像进行3D-CTA、4D-CTA相关后处理,对比3D-CTA、4D-CTA显示肿瘤大小、肿瘤供血动脉以及肿瘤与颅骨、过路动脉、周围静脉系统关系的差异。结果 3D-CTA、4D-CTA显示肿瘤大小及肿瘤供血动脉类型差异均无统计学意义(P均0.05)。3D-CTA显示70.59%(24/34)有明确引流静脉,低于4D-CTA所示94.12%(32/34,P0.05)。3D-CTA、4D-CTA显示肿瘤与颅骨关系的准确率分别为91.18%(31/34)和97.06%(33/34),肿瘤与过路动脉关系的准确率分别为87.50%(21/24)、95.83%(23/24),差异均无统计学意义(P均0.05)。结论 CT动态血管成像能够准确显示脑膜瘤大小、供血动脉及其与周围组织的关系,为术前评估脑膜瘤提供更全面的信息。     

Usefulness of three-dimensional CT angiography (3D-CTA) with a single bolus injection of contrast material for the examination of intracranial and cervical arteries in cerebrovascular disease screening]

Three-dimensional CT angiography (3D-CTA) has been gaining wide acceptance as a clinically useful tool in the field of neurosurgery. The great diagnostic value of 3D-CTA for cerebral aneurysm or other cerebrovascular diseases has been well established. However, images of the intracranial and cervical arteries have not been obtained simultaneously because of the limitation of the scanning area and the need for contrast material. In order to use 3D-CTA to screen for cerebrovascular disease, we used a helical CT scan with an intravenous single bolus injection of contrast material to perform 3D-CTA of the intracranial and cervical arteries simultaneously. A spiral computed tomographic scan was performed with a Hispeed Advantage RP (General Electric). After injection of 150 ml of nonionized contrast material at a rate of 3 mm/sec in an antecubital vein, an axial computed tomographic scan (120 kV, 200 mA) of the cranial region was performed with a delay of 20-25 seconds after starting the injection. Section thickness was 1 mm with table increments of 1 mm per rotation. The scan volume included 20-30 mm above and below the sella turcica. An axial computed tomographic scan (120 kV, 190 mA) of the cervical region was performed with a delay of 30 seconds after completion of cranial CTA. Section thickness was 3 mm with table increments of 3 mm per rotation. Image reconstruction was carried out through surface rendering and maximum intensity projection processing. From November 1995 to August 1998, we used this technique to screen 218 consecutive outpatients for cerebrovascular disease. Unruptured cerebral aneurysms were found in 20 cases (9.2%). Atherosclerotic diseases of the cervical carotid artery were found in 58 cases (26.6%), as follows: carotid artery occlusion in 2 cases, carotid bifurcation stenosis in 22 cases, and intramural calcification of the internal carotid artery in 50 cases. Atherosclerotic diseases of the intracranial artery were found in 99 cases (45.4%), as follows: middle cerebral artery occlusion in 2 cases, middle cerebral artery stenosis in 21 cases, internal carotid artery stenosis in 2 cases, and calcification of the carotid siphon in 78 cases. Although our method has various technical problems that require further improvement, we conclude that it is a useful and noninvasive diagnostic modality for screening patients for cerebral aneurysms and other cerebrovascular diseases.     

钝性外伤后胸主动脉扩张性病变的临床分析

目的 总结钝性外伤后胸主动脉扩张性病变诊疗经验.方法 回顾性分析12例钝性外伤后胸主动脉扩张性病变的临床资料,其中主动脉夹层(Stanford B型)8例以及降主动脉假性动脉瘤4例.术前螺旋CT血管造影及术中数字血管减影造影对病变进行评估,待严重合并症稳定后行腔内支架型人工血管植入术.术后3、6、12个月以及其后每年随访CTA明确治疗效果.结果 11例行腔内支架型人工血管植入术,另1例未及手术死亡.所有手术患者均获技术成功,完全或部分遮蔽左锁骨下动脉6例,支架释放后即刻造影发现内漏3例,2例球囊扩张后内漏消失,1例仅给予随访.共9例获随访(B型主动脉夹层6例、降主动脉假性动脉瘤3例),均正常生存,未出现左上肢缺血症状及神经系统阳性体征,CTA检查示近远端主动脉无新发夹层或动脉瘤,无内漏、截瘫以及支架移位等并发症.结论 钝性外伤后胸主动脉损伤多位于主动脉峡部,待重要脏器合并症稳定后行腔内支架型人工血管治疗有效可行,安全性高.     

3-Dimensional computed tomographic angiography for use of surgery planning in patients with intracranial aneurysms

Summary Background. After subarachnoid haemorrhage (SAH) diagnostic evaluation of the underlying cause is warranted since the rebleeding rate is high. The objective of the study was to answer the question, whether 3-Dimensional computed tomographic angiography (3D-CTA) is able to accurately determine the surgical indications in patients with intracranial aneurysms. Methods. After performing 3D-CTA the size of the aneurysm, direction of the aneurysmal dome, neck position and variants of the circle of Willis were analysed. Surgery was performed solely on CTA data in those cases, where the aneurysm was clearly visible. If the findings were negative or inconclusive, intra-arterial digital subtraction angiography (DSA) was also done. Findings. Between January 2001 and December 2002 100 patients (68 F, 32 M) were examined and 123 aneurysms (86 ruptured and 37 unruptured) were diagnosed. All patients received CTA preoperatively and in 27 patients selective DSA was additionally performed. Postoperatively in 34 patients the operative result was checked by DSA. A good correlation between CTA and the intra-operative findings was present in 92 of 100 patients. One aneurysm was not seen on CTA, but was on DSA. In four cases we could confirm DSA findings in CTA after re-evaluation of the data. In three cases neither CTA nor DSA clearly showed an aneurysm, but it was confirmed during surgery. A good correlation between CTA and DSA was found in 60 of 61 patients (98%). The correlation between CTA and intra-operative findings was good as expected in 92 patients, in 5 patients an aneurysm was detected on re-evaluation. Only one aneurysm could not be demonstrated by CTA but in DSA. Conclusion. CTA is less invasive, less time consuming, cheaper and easier to demonstrate the essential information regarding the aneurysm than DSA. We therefore recommend that following a careful analysis most aneurysms – 92% – can be operated solely on CTA data. Contributed equally.     

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.     

The usefulness of 3D-CTA for the diagnosis of a ruptured aneurysm at the origin of the duplicated middle cerebral artery: case report

Duplication of the middle cerebral artery is known as a rare anomalous vessel arising from the internal carotid artery and an aneurysm at the origin of the duplicated middle cerebral artery is very rare. We presented a case of ruptured aneurysm at the origin of the duplicated middle cerebral artery and discussed the usefulness of 3D-CTA (three-dimensional computed tomographic angiography) for its diagnosis. A 34-year-old female suffered from severe headache and was admitted to our hospital. CT scan revealed diffuse subarachnoid hemorrhage and angiography revealed duplication of the right middle cerebral artery and dilatation at its origin. We could not identify it as an aneurysm by angiography, so we performed 3D-CTA. 3D-CTA was able to demonstrate clearly the aneurysm at the origin of the duplicated middle cerebral artery and we performed neck clipping of the ruptured aneurysm. To our knowledge, previously there have been only 14 cases which reported such an aneurysm at the origin of a duplicated middle cerebral artery. We reviewed the 15 cases including ours and found that, in 4 cases, the aneurysm could not be detected by the initial angiography. We suspected that most of these aneurysms were small, so the detection of the aneurysms by angiography was difficult. We conclude that 3D-CTA is useful for diagnosing aneurysms at the origin of the duplicated middle cerebral artery even when thy can't be detected by angiography.     

Multi-Slice 3D-CTA – An Improvement Over Single Slice Helical CTA for Cerebral Aneurysms

Summary. Summary.   Background and Objective: The aim of this study was to demonstrate the utility of volume rendered multi-slice helical three-dimensional CT angiography in patients with cerebral aneurysm when compared with single slice CT angiography and formal digital subtraction angiography.   Methods: A prototype Toshiba Aquilon multi-slice CT scanner was employed with the following scan conditions: voltage 135 kV; current 300 mA; slice thickness 0.8 mm; scan speed 0.75 sec/cycle; couch speed 1 mm/sec; range 50 mm from foramen magnum; scan pitch 3; three dimensional images were reconstructed using multiple image projections and integral volume rendering algorithms on a Xlink/Xtension workstation. 80 cases of multi-slice CTA for cerebral aneurysm carried out at Fujita University from January 1999 to January 2001 were reviewed.   Results: The advantages of multi-slice imaging are illustrated with representative cases of cerebral aneurysm – good demonstration of three dimensional anatomy, appreciation of perforators down to 1 mm in size, delineation of the vessels around the aneurysm complex, relationship between the aneurysm and skull base, information on calcification, thrombus and blebs in the wall and eleven routine views for perusal.   Conclusion: Multi-slice CTA is a significant improvement over single slice CTA for cerebral aneurysms. It is our experience the superior and precise images produced by multi-slice technology displays anatomical information not readily available from standard DSA. Multislice 3D-CTA is relatively non-invasive and provides better and adequate detail for surgical planning. The basis of multi-slice CT angiography is described. Multi slice CTA is changing the way cerebral aneurysms are being managed nowadays. New advances in the technology of multi-slice CTA resulting in increased image resolution are outlined. Published online July 18, 2002