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.     

Surgical strategies for treatment of giant or large intracranial aneurysms: our experience with 139 cases.

Giant or large intracranial aneurysms are the vascular neurosurgeon's greatest challenge. At our department, we have treated one hundred and thirty nine patients with giant or large intracranial aneurysms between 1975 and 2001. These included 37 partially thrombosed giant aneurysms. 75 aneurysms were giant (> 2.5 cm) and 64 were large aneurysms (2-2.5 cm). Three-dimensional computed tomography angiograms were performed in patients besides MRI angiography and digital subtraction angiography. These were found to be very valuable in the preoperative assessment of surgical anatomy of the aneurysm with respect to the branch arteries and perforators origin besides knowing the relations to the skull base. With our experience in surgical treatment of these 139 cases, we find that the basic technique is trapping and evacuation and not just clipping of the aneurysm neck but also reconstruction of the artery bearing the aneurysm, especially with wide-necked aneurysms. Use of multiple clipping, tandem clipping or dome clipping as per the intraoperative situation, is very helpful in dealing with giant aneurysms as also is the use of different types of clips like fenestrated clip with straight clip (combination clipping), booster clip, dome clips etc. While selecting surgical strategy for partially thrombosed giant aneurysm, securing the neck is most important. If the neck is too narrow to reconstruct, aneurysmectomy with anastomosis is one of the surgical strategies. An extracranial intracranial bypass should be considered in cases where clipping or parent artery ligation is expected to be associated with compromise of cerebral circulation.     

双能量CT血管成像在颅内动脉瘤钛夹夹闭术后随访中的应用

目的探讨双能量CTA(DECTA)在颅内动脉瘤夹闭术后随访中的价值。方法对77例临床确诊为颅内动脉瘤并接受动脉瘤钛夹夹闭术的患者行DECTA检查,将原始数据传至后处理工作站进行图像重组,采用原始轴位图像与重建图像相结合的方式进行综合分析。结果 77例中,DECTA均能清晰显示动脉瘤夹闭情况、动脉瘤钛夹及载瘤动脉与其他颅内主要大血管的通畅情况;共84个动脉瘤接受手术夹闭,其中颅内动脉瘤完全夹闭82个,均未发生移位,动脉瘤颈残留2个;3例动脉瘤夹闭术后其他部位出现新发病灶,1例载瘤动脉血管纤细狭窄。结论 DECTA可作为颅内动脉瘤患者动脉瘤钛夹夹闭术后准确、无创的影像学随访方法。     

Assessment of brain aneurysms by using high-resolution magnetic resonance angiography after endovascular coil delivery

OBJECT: Digital subtraction (DS) angiography is the current gold standard of assessing intracranial aneurysms after coil placement. Magnetic resonance (MR) angiography offers a noninvasive, low-risk alternative, but its accuracy in delineating coil-treated aneurysms remains uncertain. The objective of this study, therefore, is to compare a high-resolution MR angiography protocol relative to DS angiography for the evaluation of coil-treated aneurysms. METHODS: In 2003, the authors initiated a prospective protocol of following up patients with coil-treated brain aneurysms using both 1.5-tesla gadolinium-enhanced MR angiography and biplanar DS angiography. Using acquired images, the subject aneurysm was independently scored for degree of remnant identified (complete obliteration, residual neck, or residual aneurysm) and the surgeon's ability to visualize the parent vessel (excellent, fair, or poor). RESULTS: Thirty-seven patients with 42 coil-treated aneurysms were enrolled for a total of 44 paired MR angiography-DS angiography tests (median 9 days between tests). An excellent correlation was found between DS and MR angiography for assessing any residual aneurysm, but not for visualizing the parent vessel (K = 0.86 for residual aneurysm and 0.10 for parent vessel visualization). Paramagnetic artifact from the coil mass was minimal, and in some cases MR angiography identified contrast permeation into the coil mass not revealed by DS angiography. An intravascular microstent typically impeded proper visualization of the parent vessel on MR angiography. CONCLUSIONS: Magnetic resonance angiography is a noninvasive and safe means of follow-up review for patients with coil-treated brain aneurysms. Compared with DS angiography, MR angiography accurately delineates residual aneurysm necks and parent vessel patency (in the absence of a stent), and offers superior visualization of contrast filling within the coil mass. Use of MR angiography may obviate the need for routine diagnostic DS angiography in select patients.     

Multislice computed tomography angiography screening for new aneurysms in patients with previously clip-treated intracranial aneurysms: Feasibility, positive predictive value, and interobserver agreement

OBJECT: Multislice computed tomography (CT) angiography may be useful for screening patients with intracranial aneurysms that are treated with clip occlusion. However, cobalt clips produce much more artifact on CT scans than titanium clips, which may hamper the evaluation of the image obtained at the clip site. METHODS: The authors screened 415 patients with previously ruptured aneurysms that had been treated using cobalt clips. Screening was performed using multislice CT angiography. The feasibility of this modality for screening these patients (based on the complication risk, CT angiography quality, and artifact avoidance) and interobserver agreement were evaluated. Patients in whom the presence of an aneurysm was suspected based on results of CT angiography studies underwent digital subtraction (DS) angiography. False-negative and false-positive findings were recorded, and the positive predictive value (PPV) was calculated. Eight patients (1.9%) had allergies to the contrast material. The quality of the CT angiography image was suboptimal in 14%. In 52%, clip artifacts hampered evaluation of the clip site. In 65 patients who underwent DS angiography, there were nine false-positive and eight false-negative reports related to aneurysms that were either small, located at the clip site, or were infundibula. The PPV on a per-patient basis was 86% (95% confidence interval [CI] 75-94%); for aneurysms at the clip site it was 83% (95% CI 61-95%); and for aneurysms at different locations it was 91% (95% CI 81-97%). The interobserver agreement was good (kappa = 0.69; 95% CI 0.60-0.78). CONCLUSIONS: Except for the evaluation of images from the clip site, CT angiography has good feasibility with good PPV and interobserver agreement. Drawbacks are that very small aneurysms can be missed and that visualization is poor at the clip site in patients in whom cobalt clips have been placed for occlusion. This second problem can be expected to resolve with the increasing use of titanium clips.     

Presurgical selection of the ideal aneurysm clip by the use of a three-dimensional planning system

Aneurysm occlusion rate after clipping is higher than after endovascular treatment. However, a certain percentage of incompletely clipped aneurysms remains. Presurgical selection of the proper aneurysm clips could potentially reduce the rate of incomplete clippings caused by inadequate clip geometry. The aim of the present study was to assess whether preoperative 3D image-based simulation allows for preoperative selection of a proper aneurysm clip for complete occlusion in individual cases. Patients harboring ruptured or unruptured cerebral aneurysms prior to surgical clipping were analyzed. CT angiography images were transferred to a 3D surgical-planning station (Dextroscope®) with imported models of 58 aneurysm clips. Intracranial vessels and aneurysms were segmented and the virtual aneurysm clips were placed at the aneurysm neck. Operating surgeons had information about the selected aneurysm clip, and patients underwent clipping. Intraoperative clip selection was documented and aneurysm occlusion rate was assessed by postoperative digital subtraction angiography. Nineteen patients were available for final analysis. In all patients, the most proximal clip at the aneurysm neck was the preselected clip. All aneurysms except one were fully occluded, as assessed by catheter angiography. One aneurysm had a small neck remnant that did not require secondary surgery and was occluded 15 months after surgery. 3D image-based preselection of a proper aneurysm clip can be translated to the operating room and avoids intraoperative clip selection. The associated occlusion rate of aneurysms is high.

     

Surgery for giant intracranial aneurysms using advanced technology

PURPOSE: Outcome of surgery for giant intracranial aneurysms is still unsatisfactory. The reason for complications is occlusion of perforators or parent arteries by the aneurysmal clipping itself or temporary occlusion of the main arteries. We report the surgical outcome of treatment of giant aneurysms using several advanced techniques which we devised to prevent these complications. MATERIALS AND METHODS: The subjects were eight patients with giant intracranial aneurysms who underwent surgery during the recent five years. Six patients had ruptured and two had unruptured aneurysms. Aneurysms were located at the ICA in five and the MCA in three patients. Aneurysmal sizes ranged from 25 to 50 mm. Preoperative 3DCTA was performed to investigate the aneurysm and the surrounding vessels in all cases. Patients with unruptured aneurysms at the ICA underwent balloon occlusion tests to check the potential for safe temporary occlusion of the parent artery, with SEP monitoring and Xe-SPECT. Intraoperative angiography and neuroendoscopes were used to prevent problems and complications which might be caused by aneurysmal clipping. RESULTS: In seven of eight cases, the aneurysmal neck was completely obliterated with clips and in one case the aneurysm was trapped with STA-MCA anastomosis. Glasgow Outcome Scale of the patients showed good recovery in six, moderately disabled (MD) in one and dead in one. The patient demonstrating MD developed hemiparesis due to vasospasm. One patient died from rebleeding of the aneurysm caused by slippage of the aneurysmal clip despite the confirmation of complete obliteration by intraoperative angiography. CONCLUSIONS: A better surgical outcome of treatment for giant aneurysms was obtained by temporary clips whose placement was based on the results of balloon occlusion test, as well as the use of intraoperative angiography and neuroendoscopes.     

Balloon-assisted microvascular clipping of paraclinoid aneurysms. Technical note

Paraclinoid aneurysms represent a significant surgical challenge. Multiple techniques have been developed to maximize the effectiveness and safety of excluding these aneurysms from the cerebral circulation. Endovascular balloons have been used for proximal control of parent arteries during the treatment of aneurysms. In this report the authors describe the technique of navigating an endovascular balloon across the neck of paraclinoid aneurysms in four patients to gain proximal control, improve the accuracy of clip placement, and reduce the risk of distal embolization of intraluminal thrombus. Six consecutive patients with giant or complex aneurysms of the ophthalmic or paraclinoid internal carotid artery that were not amenable to endovascular obliteration were retrospectively analyzed. In all six patients, the aneurysm was exposed and dissected for microsurgical clipping, and attempts were made to navigate a nondetachable, compliant silicone balloon across the neck of the aneurysm. If successfully placed, the balloon was inflated during clip placement. In four patients, the balloon was successfully navigated across the neck of the aneurysm and was inflated during clip application. Internal carotid artery tortuosity precluded navigation of the balloon into the intracranial circulation in two patients. All aneurysms were completely excluded from the parent vessel according to postoperative angiography studies. No complication occurred as a direct result of the endovascular portion of the procedure. Endovascular balloon stenting of complex paraclinoid aneurysms during microvascular clipping may provide an adjunctive therapy that facilitates safe and accurate clip placement.     

Optimizing computed tomography to reduce artifacts from titanium aneurysm clips: an in vitro study. Technical note

OBJECT: At many institutions digital subtraction angiography remains the standard imaging procedure for the postoperative evaluation of patients following placement of a cerebral aneurysm clip largely because of the artifacts produced by the clip on computed tomography (CT). The authors evaluated the effect of various imaging parameters on the quality of 3D reconstructions from CT scans while imaging a phantom to optimize the CT angiograms. METHODS: Using multidetector CT scanners with submillimeter detector collimation (0.625 mm), the authors scanned a silicone phantom with attached commercial aneurysm clips. Slice thickness, reconstruction overlap, kilovolt level, milliampere level, and pitch were varied. Neuroradiologists, who were blinded to the scanning parameters, rated the reconstructions for image quality and artifact reduction. RESULTS: Images of the titanium clip using 140 kV and 380 mA with 0.625-mm overlapping reconstructed slices provided excellent 3D visualization of both the clip and the aneurysm model, even when using two adjacent clips. CONCLUSIONS: Overlapping reconstructions combined with thin-section acquisition can provide detailed images of titanium clips and surrounding tissues without the use of low-pitch values.     

Volume-rendered helical computerized tomography angiography in the detection and characterization of intracranial aneurysms

OBJECT: The goal of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography in patients with intracranial aneurysms. The authors compared the abilities of CT angiography, digital subtraction (DS) angiography, and three-dimensional time-of-flight magnetic resonance (MR) angiography to characterize aneurysms. METHODS: Helical CT angiography was performed in 45 patients with suspected intracranial aneurysms by using volume-rendered multiplanar reformatted (MPR) images. Digital subtraction angiography was performed using biplane angiography. These studies and those performed using MR angiography were interpreted in a blinded manner. Two neurosurgeons and two interventional neuroradiologists independently graded the utility of CT angiography with respect to aneurysm characterization. Fifty-five aneurysms were detected. Of these, 48 were evaluated for treatment. Computerized tomography angiography was judged to be superior to both DS and MR angiography in the evaluation of the arterial branching pattern at the aneurysm neck (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.007), aneurysm neck geometry (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.001), arterial branch incorporation (compared with DS angiography, p = 0.021, and with MR angiography, p = 0.001), mural thrombus (compared with DS angiography, p < 0.001), and mural calcification (compared with DS angiography, p < 0.001, and with MR angiography, p < 0.001). For surgical cases, CT angiography had a significant impact on treatment path (p = 0.001), operative approach (p = 0.001), and preoperative clip selection (p < 0.001). For endovascular cases, CT angiography had an impact on treatment path (p < 0.02), DS angiography study time (p = 0.01), contrast agent usage (p = 0.01), and coil selection (p = 0.02). Computerized tomography angiography provided unique information about 39 (81%) of 48 aneurysms, especially when compared with DS angiography (p = 0.003). The sensitivity and specificity of CT angiography compared with DS angiography was 1. The sensitivity and specificity of CT and DS angiography studies compared with operative findings were 0.98 and 1, respectively. CONCLUSIONS: Computerized tomography angiography is equal to DS angiography in the detection and superior to DS angiography and MR angiography in the characterization of brain aneurysms. Information contained in volume-rendered CT angiography images had a significant impact on case management.     

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.     

三维数字减影血管造影血管虚拟内镜成像在颅内动脉瘤诊治中的作用

目的探讨三维数字减影血管造影（three dimensional digital subtraction angiography,3D DSA）血管虚拟内镜成像在颅内动脉瘤诊治中的作用。方法回顾性分析53例颅内动脉瘤三维DSA血管虚拟内镜成像资料并应用三维DSA血管虚拟内镜成像随访术后载瘤血管及瘤颈残留情况。三维的旋转数字图像由脑血管造影机球管和影像增强器的同步2次240°旋转获得,应用Volume Viewer软件对原始三维图像进行重建,固定密度值并选取感兴趣区,用Navigator软件进行血管虚拟内镜成像,观察血管腔内结构。结果 53例术前三维DSA血管虚拟内镜成像清晰,共检出动脉瘤62个,其中动脉瘤体有穿支血管发出19例（15例手术证实）,动脉瘤内有血栓形成7例（4例手术证实）,载瘤动脉内有动脉粥样硬化斑块5例（3例手术证实）。术后31例3D DSA随访：28例未见瘤颈残留,2例出现载瘤动脉轻度狭窄;2例弹簧圈突入载瘤动脉血管腔内;1例动脉瘤栓塞后瘤颈复发残留,再次开颅夹闭动脉瘤。结论三维DSA血管虚拟内镜成像是一种安全有效的评估颅内动脉瘤管腔结构的方法,不仅可以用于动脉瘤的术前判断,指导手术方式的选择,也可以用于动脉瘤术后的随访,为明确术后载瘤动脉及瘤颈情况提供依据。     

多技术联合应用于颅内巨大动脉瘤的显微外科治疗

目的 探讨神经电生理监测、术中超声、术中荧光造影、神经内镜多技术联合应用于颅内巨大动脉瘤的显微外科手术治疗的临床效果。方法 回顾性分析显微手术治疗颅内巨大动脉瘤17例的临床资料。术前采用3D-CTA、MRI和DSA,充分评估动脉瘤的位置、大小和形状。术中应用神经电生理监测评价动脉瘤夹闭前、后的神经功能保留和损害程度;通过微血管多普勒超声的定性和定量分析联合术中荧光造影评定动脉瘤和周围邻近血管的血液流速及通畅度;神经内镜观察动脉瘤区的局部解剖,辨认重要的穿支血管、瘤颈结构和动脉瘤夹情况。手术在手术显微镜下操作,采用载瘤动脉控制性技术、瘤颈成形技术、动脉瘤内减压和切除技术、多瘤夹夹闭技术和血管痉挛保护技术等进行联合治疗。 结果 在多技术联合监测下,显微外科手术成功夹闭巨大动脉瘤17个,术后恢复良好15例,出现轻偏瘫1例,重度偏瘫l例,无死亡病例。DSA复查示瘤颈夹闭完全,载瘤动脉通畅。远期随访仍在进行中。 结论 多技术联合显微手术技术,能有效提高颅内巨大动脉瘤的手术疗效。     

Open surgery of giant paraclinoid aneurysms improved by intraoperative angiography and endovascular retrograde suction decompression

Summary In three consecutive cases of giant left sided paraclinoid aneurysms we employed an endovascular retrograde suction decompression technique in combination with intra-operative angiography. A double-lumen balloon catheter was placed in the left internal carotid artery by the transfemoral route. After balloon inflation and placement of a temporary clip distal to the aneurysm blood was aspirated and the aneurysm collapsed. Thus further dissection of the aneurysm could easily be achieved and clips could be placed. Afterwards real-time digital subtraction angiography was performed. Intra-operative angiography led to clip repositioning in all cases either due to a clip induced stenosis of the parent vessel, or because of incomplete aneurysm obliteration. Afterwards successful clipping could be confirmed in all cases. Outcome was excellent in one case, good in the other. The third case, extremely complicated by an accompanying craniopharyngioma, showed a satisfactory outcome, but presented new neurological deficits.     

Routine intraoperative angiography during aneurysm surgery

OBJECT: The routine use of intraoperative angiography as an aid in the surgical treatment of aneurysms is uncommon. The advantages of the ability to visualize residual aneurysm or unintended occlusion of parent vessels intraoperatively must be weighed against the complications associated with repeated angiography and prolonged vascular access. The authors reviewed the results of their routine use of intraoperative angiography to determine its safety and efficacy. METHODS: Prospectively gathered data from all aneurysm cases treated surgically between January 1996 and June 2000 were reviewed. A total of 303 operations were performed in 284 patients with aneurysms; 24 patients also underwent postoperative angiography. Findings on intraoperative angiographic studies prompted reexploration and clip readjustment in 37 (11%) of the 337 aneurysms clipped. Angiography revealed parent vessel occlusion in 10 cases (3%), residual aneurysm in 22 cases (6.5%), and both residual lesion and parent vessel occlusion in five cases (1.5%). When compared with subsequent postoperative imaging, false-negative results were found on two intraoperative angiograms (8.3%) and a false-positive result was found on one (4.2%). Postoperative angiograms obtained in both false-negative cases revealed residual anterior communicating artery aneurysms. Both of these aneurysms also subsequently rebled, requiring reoperation. In the group that underwent intraoperative angiography, in 303 operations eight patients (2.6%) suffered complications, of which only one was neurological. CONCLUSIONS: In the surgical treatment of intracranial aneurysms, the use of routine intraoperative angiography is safe and helpful in a significant number of cases, although it does not replace careful intraoperative inspection of the surgical field.     

Complete neck clipping of internal carotid-posterior communicating artery aneurysms using bayonet-shaped aneurysm clips: technical note

Neck clipping for internal carotid-posterior communicating artery (IC-PC) aneurysms using standard straight, angled, or curved clip may result in remnant aneurysm neck. We describe complete neck clipping of IC-PC aneurysms using a bayonet-shaped clip. The bayonet-shaped clip is applied perpendicular to the long axis of the internal carotid artery (ICA), and the blades of the clip are inserted between the aneurysm neck and the ICA. Using the clip applicator, the clip is gradually rotated counterclockwise or clockwise for left or right ICA aneurysm, respectively, so that the distal and shank portions of the clip blade are located at the aneurysm neck in the posterior communicating artery (Pcom) and ICA, respectively. As a result, the distal flexure of the clip blade fits the junction of the ICA and Pcom. This technique was used in four patients with ruptured ICA aneurysms and five patients with unruptured ICA aneurysms. Postoperative cerebral angiography demonstrated no residual aneurysm neck and preservation of the Pcom in all patients. This technique is useful for cases of IC-PC aneurysm involving the origin of the Pcom.     

颅底Willis环前部大或巨大动脉瘤的手术治疗

目的 研究３Ｄ－ＣＴＡ的诊断技术和改进显微外科手术技术,以提高Ｗｉｌｌｉｓ环前部大或蔬大动脉瘤的手术疗效。方法 回顾性分析作者自１９８５年１０月至１９９８年１２月手术治疗Ｗｉｌｌｉｓ前部环大、巨大动脉瘤２８例。在诊断上,术前采用３Ｄ－ＣＴＡ以发现和勾划动脉瘤,并与ＤＳＡ对照。在手术上采用颅底入路、近准则载瘤动脉暂时性阻断、动脉瘤内减压、多瘤夹夹闭、瘤颈逐步缩窄、动脉瘤切除等技术。结果 出院时优良者     

Clinical application of 16-row multislice computed tomographic angiography in the preoperative and postoperative evaluation of intracranial aneurysms for surgical clipping

BACKGROUND: Sixteen-row multislice CTA has great potential for use in the studies of intracranial aneurysms. The aim of the study was to assess the clinical application of 16-row multislice CTA in the preoperative and postoperative evaluation of intracranial aneurysms for surgical clipping. METHODS: A total of 42 patients (45 aneurysms) underwent surgery using titanium clips. The CTA was performed with a 16-row multislice CT machine; detector slice, 0.75 mm; reconstruction interval, 0.40 mm; and timing determined by bolus trigger. The neuroradiologist independently evaluated the shape, size, and location of aneurysms; the relationship to other structures; and the presence of neck remnants and patency of the parent artery after clipping on MIP images, VR imaging, and thin-slab MIP and VR images. RESULTS: Sixteen-slice CTA clearly provided the shape and location of aneurysms, the size of the sac and the neck, and the relationship of aneurysms to bone structures and adjacent branch vessels; and this information would help the neurosurgeons find aneurysms and clip them successfully. Three clipped aneurysms with neck remnants were identified by the 16-slice CTA, and the parent artery could be reliably evaluated close to the clip. CONCLUSION: Sixteen-slice CTA is a useful reference for patients undergoing surgical clipping of aneurysms and can provide much effective information to clipped aneurysms.     

Intraoperative factors associated with surgical outcome in patients with unruptured cerebral aneurysms: the experience of a single surgeon

OBJECT: Some well-known predictors of clinical outcomes in patients with ruptured aneurysms are not useful for forecasting outcome in patients with unruptured aneurysms. The goal of this study was to analyze outcomes in patients harboring unruptured cerebral aneurysms in different locations and to create a predictive tool for assessing both favorable outcome and morbidity in a large series of unruptured aneurysms. METHODS: The authors analyzed data from 387 patients with nonruptured intracranial cerebral aneurysms who underwent surgery for clip placement. Intraoperative data were reviewed and seven factors that might influence outcomes were identified. These included the following: 1) aneurysm size larger than 10 mm; 2) presence of a broad aneurysm neck; 3) presence of plaque calcification near the aneurysm neck; 4) application of clips to more than one aneurysm during the same surgery; 5) temporary occlusion; 6) multiple clip applications and repositioning; and 7) use of multiple clips. The entire group of patients with unruptured aneurysms was divided into two subgroups on the basis of outcome. Each patient was subsequently assessed to formulate the factor accumulation index (FAI), the sum of different factors observed in a given patient. The subgroup of patients with expected outcomes was composed of 312 patients, whereas the subgroup of unexpected outcomes consisted of 31 patients. Depending on the anatomical locations of the aneurysms, the combined mortality-morbidity rate ranged from 5.7 to 25%, with the best results for patients harboring ophthalmic artery aneurysms and the worst results for those with vertebrobasilar system (VBS) aneurysms. The majority of patients with expected outcomes who harbored aneurysms of the middle cerebral artery, the internal carotid artery, and the VBS had a lower FAI, whereas the majority of patients with unexpected outcomes had a higher FAI. CONCLUSIONS: It is possible to predict outcomes in patients with unruptured cerebral artery aneurysms by calculating the FAI. The rate of postoperative morbidity increases with the FAI within the range of three to four factors.